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  • 1975-1979  (1,152)
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  • Chemical Engineering  (386)
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  • 1995-1999  (50)
  • 1975-1979  (1,152)
  • 1920-1924
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 61-67 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Risk assessments have been performed to determine the risk associated with the transportation of hazardous wastes through a city. In the course of these assessments, a number of modeling issues arose relating to transportation accident rates, the characterization of incidents, the effect of thermal radiation, the impact of exposure to toxic chemicals, and the threshold for acceptable risk. This paper discusses these issues.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 98-103 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents the design of ribbon wound pressure vessels useful for Ammonia, Urea and Methanol plants. The design is to create a thin shell of 1/5 the total wall thickness required, weld it to the end pieces, and wind 4 to 8 mm thick ribbons of 80 mm width at an angle of 15 to 30 degrees on the inner shell, using a prestress. The ribbons are welded at the ends and an even number of layers are wound cross-helically on to the shell. With more than 7000 vessels over the pressure range of 50 to 350 atmospheres in use in the various chemical industries in China over the past 30 years, their safety record has been excellent. Of particular interest has been the application of this technology in the Ammonia and Urea plants, where the design allows fabrication of these vessels at substantial reduction in cost, and early delivery, when compared to the mono wall technology.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 20-22 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Most audits try to look at a representative selection of the plant procedures and equipment. An alternative is a survey, a look in depth at selected procedures (such as those for testing alarms and trips, issuing permits-to-work, controlling modifications, taking samples or testing relief devices) or selected equipment (such as level glasses or equipment for handling LPG). If the procedure or equipment is well-chosen, surveys may make a bigger contribution to safety, per person-hour, than a conventional audit.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 39-42 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Under OSHA 1910.119, all Process Safety Management (PSM) facilities are required to keep their pressure relief system design information current. This article demonstrates why a pressure relief system design verification effort must be based on an equipment list, rather than a relief device list, in order to ensure that every piece of equipment is adequately protected. The formerly common practice of simply checking the design bases of all existing relief devices is deficient is deficient since this technique does not systematically ensure that every piece of equipment is protected.The “Berwanger Method” is a step by step process for designing or analyzing a pressure relief system to meet OSHA 1910.119 Process Safety Information (PSI) and Process Hazard Analysis (PHA) mandates. The method uses a relational database which tracks the relationships between protected equipment, potential overpressure scenarios, and protective devices.The challenge facing an operating company does not end once the design basis has been “verified” - the design basis information must also be maintained and be readily accessible to avoid costly reinvention of the wheel down the road. The “Berwanger Method” also addresses these maintenance issues.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 49-60 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper reports on a comprehensive literature search and small scale experimental work on the reaction characteristics of phosphorous trichloride and water. More than 30 tests were conducted, including both closed and open test cells. The water to phosphorus trichloride molar ratio was varied from 1 to 25. When in contact, water and phosphorus trichloride will form two liquid layers with a reaction starting at the interface. The impact of variables on reaction rates including the interface surface area, layer depth, and stirring were investigated experimentally. A reaction rate model that fits all the measured data is presented. Case studies illustrating the use of this data for emergency relief systems and vent containment design are presented in reference. [1].
    Additional Material: 10 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 68-73 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two major accidents in the 80's: the summit Tunnel Fire, England and Piper Alpha disaster, an offshore platform in the North Sea; and very recently, possible explosion of the Boeing, TWA flight 800 at New York, makes it imperative that further research into the mechonisms of the ignition of flammable vapor/air mixture in contact with hot surfaces needs to be done. There have been a number of studies of ignition by hot surfaces, but in all these studies the ignition sources were wire, sphere or strip, i.e., most of them were flat surfaces. But to the authors' knowledge, other variables which affect the ignition mechanism such as irregular geometrical shapes have not been studied. The purpose of this paper is to examine how the degree of confinement (or, configuration), size and orientation, of the heated surface affects the ignition temperature of the flammable vapors. The results were obtained by experimentnal and by computational fluid dynamics.
    Additional Material: 13 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 9-15 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The design and deflagration pressure relief vents is based on correlations developed for various types of combustible materials and for enclosures of different strengths. The primary guideline for deflagration vent design in the US is NFPA 68 Guide for Venting of Deflagrations [5]. That document gives guidance for the design of vents for enclosures containing flammable gases, specifically hydrogen, coke oven gas, propane, and methane. Application of the guide to other gases is achieved using the KG value. Values of KG are published for a relatively small number of gases, as seen in Table D-1 of NFPA 68. This work present KG data on several additional gases obtained in a laboratory scale test vessel along with analysis of the results with respect to published values of fundamental burning velocity.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 23-31 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In May 1996, the Flammable and Combustible Liquids Code Committee of the National Fire Protection Association (NFPA) proposed for adoption by the Association a new edition of NFPA 30, Flammable and Combustible Liquids Code. This new edition was the culmination of two and one-half years' work by the Committee and included one of the most significant changes to that document in some twenty years: the incorporation of mandatory fire protection criteria for warehouses and other inside areas that store flammable and combustible liquids in containers and portable tanks.
    Additional Material: 2 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 32-38 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper describes the development of a risk ranked Inspection Recommendation procedure that is used by one of Exxon's chemical plants to prioritize repairs that have been identified during equipment inspection.As part of the Company's Safety Management Practices initiative in the late 1980's a procedure was put into place to ensure that an Inspector's repair recommendations were properly addressed by the organization. The initial procedures were successful at “systematizing” the documentation and stewardship-to-completion of the Inspector's recommendation, however, there were complications with the original process: (1)The Inspector made a simple High, Medium or Low assessment of the priority/criticality of the recommendation. Frequently, this resulted in disagreements with Operations about the true priority of the recommendation.(2)If there was agreement on the priority of the recommendation, there was still disagreement on the relative rank within the priority-which high priority was the highest priority?(3)With limited funds to spend on repairs, it was (and is) important to make sure that the money was being spent on the highest risk items that had the greatest risk reduction/cost benefit ratio.To address these concerns, the procedure was modified to incorporate a risk assessment of the recommendation by both the Inspector and Operations. In the new procedure, the Inspector describes the deficiency that he/she finds and assesses the probability of failure within a certain time-frame. Operations must assess the consequences, from an environmental, safety and economics standpoint, were the failure to occur. These assessments are combined in the typical risk equation (risk = probability × consequences) to arrive at a severity index which serves to rank the recommendation relative to the other recommendations. Because Operations participates in the assessment there is very little disagreement about the priority of the recommendation. The severity index puts the recommendations in order so it is quite clear which are the highest priority recommendations. This process has helped to focus the entire organization on those deficiencies that represent the greatest risk with the result that less time and money is spent correcting items that have a low risk/cost benefit ratio, allowing these savings to be used to reduce the higher risks in the plant.
    Additional Material: 4 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 124-126 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple analytical method is presented for estimating the hybrid minimum ignition energy (HMIE) of dust-gas mixtures, based on the assumed generality of Bartknecht's well-known test data for mixtures of propane with a series of dusts in air. Since the HMIE equation requires input data which might be unavailable, the use of conservative default methods is discussed.
    Additional Material: 1 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 138-148 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A large and potentially hazardous decrease in aldehyde autoignition temperature (AIT) occurs with increased pressure. The AIT-pressure curve determined in a 5 L stainless steel sphere was similar for propionaldehyde and butyraldehyde in air, falling from about 185°C at atmospheric pressure to 90°C at 140 psia. Reduction of oxygen concentration had little effect on propionaldehyde AIT. At 100°C and 140 psia, autoignitions accompanied by at least a doubling of pressure were observed above 4% oxygen. In the presence of a few grams of free liquid, propionaldehyde vapor ignited in air at initial conditions significantly below the AIT. The mechanism appears to involve rapid Fe-catalyzed exothermic liquid-phase oxidation leading to autoignition of the adjacent heated gas layer. An acetaldehyde vapor-air mixture in the presence of free liquid and rust exploded at room temperature when air pressure was increased to 95 psia; this result is discussed with reference to a cylinder overpressurization that occurred while making up an ostensibly sub-LFL calibration mixture with compressed air. Propionaldehyde's limiting oxygen concentration (LOC) was investigated in the near-autoignition region using the same 5L apparatus; the findings are discussed with reference to an overpressurization incident in an air-liquid partial oxidation reactor. The general results are used to illustrate the application of LOC in partial oxidation processes subject to autoignition and to discuss elements of the current ASTM draft test method for LOC, which does not address test difficulties associated with condensable and/or reactive gas systems.
    Additional Material: 16 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. F3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 157-170 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Risk analysis in chemical process industries is an elaborate exercise involving several steps from preliminary hazard identification to development of credible accident scenarios, to preparation of strategies for prevention or control of damage.All this requires substantial inputs of time and money. In order to get an approximate yet workable assessment of risk at much lesser costs, indices have been developed which link typical findings of elaborate risk analysis to scales of risk. The scales, in turn, provide workable measures of hazards/risks/safety.In the past, indices have been reported for swift risk assessment - the noteworthy among them include Dow fire and explosion index, Mond fire, explosion and toxicity index, IFAL index, and mortality index. A few rapid ranking techniques have also been proposed.This paper presents a new system of methodologies for Hazard Identification and Ranking (HIRA). The system consists of two indices: one for fire and explosion hazards and another for the hazard due to likely release of toxic chemical. The magnitudes of these indices indicate the severity of the likely accident; in terms of the size of the impacted area.HIRA has been applied to a typical chemical process industry - a sulfolane plant - and its performance has been compared with that of the Dow's and the Mond's indices. The study reveals that HIRA is more sensitive and accurate than the other indices.
    Additional Material: 12 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 200-208 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 213-218 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: On October 31, 1987 a crane lifting a heat exchanger convection section failed and severed a 4″ loading line and a 2″ pressure relief line to an HF alkylation reactor settler drum at a petroleum refinery in Texas City, Texas. Vapors were emitted under pressure for about two hours and the vessel was plugged and drained aproximately 44 hours later. A plume from this accidental release passed through residential areas, damaging some vegetation (brown lawns), and spawning a class action law suit. An extensive analysis was conducted to determine the total inventory loss and to model the blowdown process and the concentrations of HF in the plume. Since the discharge rate was decreasing with time, a peak concentration of HF in the emitted vapors occurred just before the water spray mitigation system became fully operative. Consequently, the mitigation efforts were more effective late in the response when concentrations were already low. The predicted plume concentrations are consistent with observed vegetation damage effects, with concentrations below Emergency Response Planning Guideline Level 3 past 3/4 mile from the source. These results support a policy of sheltering in place during such an event.
    Additional Material: 8 Ill.
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  • 18
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fifty-five gallon steel drum of a liquid organic peroxide pressurized and ruptured in the mix room of a manufacturing plant. The head of the drum blew off and the ejected material ignited. The resulting fire was extinguished by the building sprinkler system and operating personnel. Although there were no injuries, the fire caused significant damage in the mix room. The investigation of this incident, its likely cause, and the corrective actions will be discussed.
    Additional Material: 9 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 238-242 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Brazoria County Petrochemical Council, 13 companies that are working together to enhance relations between industry and the community, united in a joint effort at complying with the EPA's Risk Management Program. One of the significant issues the group had to address was the need to develop meaningful hazard assessment for presentation to the public. The EPA's “Table Look-Up Approach” found in the Offsite Consequence Analysis Guidance document is certainly a good tool; however, the built-in conservatism results in over-estimates of potential hazard areas. Much more meaningful results are shown to be obtained using one of the hazard release models.The value of using a credible scenario with realistic meteorological data is demonstrated through the consistently smaller areas predicted by the PHAST Model for planning purposes. Realistic scenarios/failure modes and realistic model parameters are important so that the risk to the public is not overstated. Proprietary models such as PHAST are invaluable in providing more meaningful consequences for planning purposes.
    Additional Material: 2 Tab.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 263-271 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Some of the hazards encountered by process plant operators involve the operation of in-line valves to control, start, and to stop flow. Torque required to operate valves may vary according to valve wheel size, in-line pressure, and valve flange position (open/closed). This study determined how valve wheel size, in-line pressure and valve position (open/closed) affect torque required to actuate a valve. Data were gathered with each combination of size, pressure and position for 336 valves in an operating petrochemical process facility. The results indicate that the main effects of valve wheel size, the in-line pressure, and open/closed valve position significantly affect operational torque requirements. In addition, the interaction between position and pressure was significant for operational torque. The implication of these results is that operators are exposed to operational torque requirements that exceed maximum acceptable capabilities that have been determined in previous studies.
    Additional Material: 12 Ill.
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  • 21
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 288-296 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An ammonia storage tank was built at the BASF Antwerp site in 1969 on land reclaimed from the sea. After several years of operation uneven foundation settlement, of up 2, occurred. In order to assure stability of this area for the next operation period (at least 10 years) measures were taken to ensure continued safe operation. One key measure was strain gauge monitoring at the location of maximum stress.
    Additional Material: 19 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 297-301 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Baker-Strehlow methodology was developed to provide an objective approach to prediction of blast pressures from vapor cloud explosions. The complete methodology was first published in 1994 [1]. Since then, it has evolved through ongoing research and use in VCE hazard analyses, facility siting studies and accident investigations. This article gives a brief overview of a paper on recent developments in the Baker-Strehlow methodology presented at the 31st Loss Prevention Symposium in Houston on March 9-13, 1997. Because the entire paper is too lengthy to be presented here, the following discussions may be lacking in some details. A copy of the complete paper can be obtained from the American Institute of Chemical Engineers (AIChE).Since the Baker-Strehlow method was first published, it has been used extensively in VCE hazard assessments in refineries and chemical plants. As expected, many practical lessons have been learned during the course of the hazard assessments, and the Baker-Strehlow method has evolved as a result. The changes have been evolutionary, not revolutionary. In keeping with the goals of the original study in which the methodology was developed, all changes have been incorporated with the intent of achieving an objective methodology to provide consistent prediction of VCE blast effects.The revisions to the Baker-Strehlow method resulting from experience gained during plant walk-downs and hazard assessments include: Systematic identification of “potential explosion sites” or “PESs,”Selection of the level of confinement for mixed zones of 2D and 3D confinement,Deciding on flame expansion when confinement is elevated above the vapor cloud,Selecting the reactivity for a fuel that is a mixture of fuels with differing reactivities,Predicting blast loads when there are multiple PES's within a vapor cloud considering different ignition source locations.
    Additional Material: 4 Ill.
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  • 23
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 83-85 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Safety, health and loss prevention are major areas of interst for the American Institute of Chemical Engineers (AIChE). There has been an evolution of these concerns over the years in the Institute just as it has in industry. This article chronicles this evolution.
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  • 24
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 25
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 1-8 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Recent guidelines released by the U.S. EPA define a worst-case scenario as a release under stable atmospheric conditions defined as Pasquil-Gifford stability class F. Unfortunately, very few tests at F stability have been available heretofore to provide a basis for models. Recent test data with propane releases by the German research organization TUV provide a set of 60 experiments conducted specifically to define the effects of atmospheric stability class on dispersion. Of these, 25 tests were at F stability. A comparable number were at each other stability class A through E. In addition 23 tests were at wind speeds under 1.5 m/s in stable atmospheres. This paper reports on adjustments made to our models based on these new data by reducing the originally-postulated sensitivity to stability class. In spite of considerable scatter in the TUV data, particularly between two different types of propane analyzers, the model allows us to extract information by averaging over the tests.
    Additional Material: 15 Ill.
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  • 26
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 16-19 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A multi-disciplinary team developed a guideline for determining access restriction zones around vented solids handling equipment. The guideline provides a method for ensuring the discharge from a vented explosion will not cause injury to personnel. The steps in this method include: calculating the extent of external hazards from vented explosions; identifying potential areas where personnel could be exposed to a hazard; identifying ways to eliminate or reduce the hazard area; and establishing and documenting any access restrictions needed. Hazard zone calculations use the latest knowledge from research into fireball size, flame length and external pressure equations in VDI 3673. The guideline provides guidance for using this information. Options for mitigating or reducing external hazards from vented explosions are also described. As part of the project, the team audited several solids handling systems to look for potential oversights in existing restricted access areas. Some of the team's learnings from these audits are reviewed.
    Additional Material: 2 Ill.
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  • 27
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 43-48 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper defines situation awareness (SA) and discusses its importance to operator-machine system safety and functioning in the context of process control activities. Specifically, identified are relationships of human detection of critical process cues converying the status of automated control systems and operator interpretation of the meaning and relevance of such information to the potential for negative incidents in chemical processing. Beyond individual operator SA in interacting with control systems, intra- and inter- work team SA are discussed for supporting individual attainment of process control responsibilities. Factors critical to team SA are discussed. “Road blocks” to team SA are also analytically examined. Lastly, methods for assessing individual and team SA are reviewed and vehicles for relating outcomes of these methods to changes in process control operator and team behavior to improve human-machine system safety and performance are relayed.
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  • 28
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 29
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    Process Safety Progress 17 (1998), S. 74-81 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The knowledge of the ingition behavior of dust-air mixtures due to electrical sparks (MIE, Minimum Ignition Energy) and hot surfaces (MIT, Minimum Ignition Temperature) is important for risk assessments in chemical production plants. The ignition behavior determines the extent and hence the cost of preventive protection measures.This paper describes the use of the minimum ignition energy and minimum ignition temperature as very important safety indexes in practice.Based on the latest results from large scale experiments on pneumatic filling of silos with polymeric materials and new results of full scale filling tests using Flexible Intermediate Bulk Containers (FIBC) manufactured from a variety of materials, guidance can be given to ensure safe operation in different situations such as filling, emptying operations, type of powder handled.The aim of this paper is to assist people dealing with product. It reflects the present state of the art and current knowledge of the assessment and measures associated with powder handling.
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    Process Safety Progress 17 (1998), S. 104-106 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In mid-1997, an Advanced Process Control (APC) scheme was implemented at a resins manufacturing complex with the goal of minimizing flare fuel gas usage while maintaining sufficient energy (BTU/SCF flare gas) to be in environmental regulatory compliance. Prior to APC implementation, the flare system was manually controlled by plant operators with minor attention paid to the minimization of fuel gas usage. Since implementation, APC has saved the plant thousands of dollars in fuel gas costs and reduced unnecessary combusted fuel gas emissions.Hazard analysis techniques were used in the development of the control scheme. An overview of the APC used, the economic evaluation, and the hazard analysis techniques used in the project are presented here.
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    Process Safety Progress 17 (1998), S. 107-123 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the risk assessment parlance, especially with reference to chemical process industries, the term “domino effect” is used to denote “chain of accidents,” or situations when a fire/explosion/missile/toxic load generated by an accident in one unit in an industry causes secondary and higher order accidents in other units. The multi-accident catastrophe which occurred in a refinery at Vishakhapatnam, India, on September 14, 1997, claiming 60 lives and causing damages to property worth over Rs 600 million, is the most recent example of the damage potential of domino effect.But, even as the domino effect has been documented since 1947, very little attention has been paid towards modeling this phenomena. In this paper we have provided a conceptual framework based on sets of appropriate models to forecast domino effects, and assess their likely magnitudes and adverse impacts, while conducting risk assessment in a chemical process industry. The utilizability of the framework has been illustrated with a case study.
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  • 32
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    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 33
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    Process Safety Progress 17 (1998), S. 149-154 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article deals with fire protection for water miscible flammable liquids stored in plastic containers packaged in boxes located on pallets. A series of fire tests was conducted with palletized rack storage arrangements using in-rack sprinkler protection at various levels. The intent of the paper is to present data from this test series for these types of commodities. The paper will identify various existing water miscible flammable liquid products stored in this fashion and provide background information for protecting this type of storage as it relates to NFPA 30 Flammable and Combustible Liquids Code. The test data indicates that further research work is needed in the area of plastic containers for use with the storage of combustible and flammable liquids. Included in the paper are discussions concerning possible protection strategies and suggestions for future research which would benefit those involved in risk management of this type of commodity.
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  • 34
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    Process Safety Progress 17 (1998), S. 176-183 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The safest method to prevent fires and explosions of flammable mixtures in the first place. This method requires detailed knowledge of the flammability region as a function of the fuel, oxygen, and nitrogen concentrations. A triangular flammability diagram is the most useful tool to display the flammability region, and to determine if a flammable mixture is present during plant operations.This paper describes how to draw and use a flammability diagram. A procedure to estimate the flammability region using the available and sometimes limited data is discussed. The paper also shows how to use the flammability diagram with plant operations involving inerting and purging, and from bringing vessels into and out of service. A compilation of flammability diagrams for 30 materials, based on previously published data is provided.An automated apparatus for acquiring data for a flammability diagram is described. The apparatus consists of a 20-L sphere with an automated gas mixing system, a fuse-wire ignition system, and a high speed pressure measurement and data acquisition system. Data derived from the apparatus includes flammability limits, maximum pressure during combustion, and the maximum pressure rate. The effect of fuse-wire ignitor dynamics on the results is studied. A flammability diagram for methane drawn from data obtained from the apparatus, is presented.
    Additional Material: 18 Ill.
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  • 35
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    Process Safety Progress 17 (1998), S. 86-97 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Regulatory issues related to material safety have made the accurate measurement and/or prediction of flash points essential. The flash point is one of the major physical properties used to determine the fire and explosion hazards of a liquid. Flash points are used by virtually all governmental entities worldwide to define “flammable” and “combustible” materials for shipping and safety regulations.A model is described here for the calculation of closed cup flash points for multicomponent, single liquid phase, mixtures. The model is based upon rigorous vapor/liquid equilibrium calculations supplemented with information about the lower flammable limits (LFL's) and heats of combustion (ΔHc's) for the mixture's constituent components. The closed cup flash points predicted with this model are typically within ± 5°C of the experimentally reported values. Such a model is useful as a means of verifying experimental data and as a tool for screening product formulations prior to experimental flash point determination. The model should considerably enhance the safety evaluation portion of the product development cycle, thus leading to shortened product time-to-market cycles. While flash points calculated with this model are in excellent agreement with experiment, experimental determination is still encouraged for critìcal safety applications.
    Additional Material: 15 Ill.
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  • 36
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    Process Safety Progress 17 (1998), S. 134-137 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: National Advisory Committee's Acute Exposure Guideline Levels (AEGLs) for ammonia are critically evaluated. The technical bases for concern about AEGL-2 and AEGL-3 values derived by the committee are summarized recommendations made.
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  • 37
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    Process Safety Progress 17 (1998), S. 127-133 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An explosion and flash fire in a fixed bed reactor occurred at a municipal wastewater treatment plant (WWTP). Two employees were injured in the accident. The accident occurred in an ozone treatment building where ozone was used to treat odors from the offgas of the sludge concentration units. Excess ozone manually was routed to the fixed bed reactor (ozone destruct unit) where the ozone is catalytically transformed into oxygen before being discharged to the atmosphere.An investigation of the accident was conducted to determine the root cause of the explosion and flash fire and identify corrective actions which the WWTP management could undertake to prevent a recurrence. This investigation included site inspections, interview with the injured employees, sampling and analysis of various materials, an explosion dynamics analysis, and a root cause analysis.It was concluded that cooling oil from one of the ozone generation units entered the main ozone gas line due to a crack in one of the reactor's dielectric tubes. The cooling oil was vented into the ozone destruct unit when an employee opened a ball valve on the main ozone gas line. The cooling oil, essentially a saturated hydrocarbon mixture, reacted exothermically when it contacted the manganese dioxide catalyst. The exothermic reaction resulted in an explosion which propelled the access panel outwards and dispersed the catalyst pellets. A flash fire followed the explosion. The flash fire burned two employees and caused thermal damage to a nearby control panel.Although this accident was the first of its kind at this facility, this was not the first time that the ozone generator had experienced a failure of a dielectric tube. Thus, there was a significant probability that a dielectric tube failure could leak cooling oil into the main ozone gas line. This failure event could, in turn, result in another explosion and flash fire. The WWTP staff neither designed nor fabricated the ozone generator-destructor system. Therefore, it did not seem appropriate for the WWTP staff to modify the ozone system. Instead, it was recommended that the ozone destruct unit be taken out of service. The WWTP management acted on this recommendation.
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    Process Safety Progress 17 (1998), S. 171-175 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An explosion occurred in a petroleum product storage tank at a refinery. The liquid petroleum product was a heavy oil used as an asphalt extender. There were no injuries, but the cleanup was costly. The storage tank was one of several which received the product stream from a dehydration unit. The accident occurred shortly after the refinery was brought back on-line following a shutdown for schduled maintenance.This was the first incident of this kind to occur at this facility. Analysis of the process data and eyewitness observations indicated that the dehydration tower, which was supposed to be maintained at a minimum of 100°C during the shutdown, was allowed to drift below 100°C for an unknown period of time. This deviation enabled liquid water to enter the storage tank. Three operational factors contributed to the accident. Corrective actions were recommended to prevent a recurrence of a similar incident.
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  • 39
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    Process Safety Progress 17 (1998), S. 184-189 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dust explosions have been with us for a long time. The first record of a dust explosion occurred in Turin, Italy, on December 14, 1785 [1]. The detailed record of this event is left to us by Count Morozzo. The event took place in Mr. Giacomelli's bakery. We know from his account that the weather was unseasonably dry, that a boy who worked in the bakery was using a shovel to stir and transfer the flour to a chute from a store room to the bakery and he had a lighted lamp to work by. The rest, as the saying goes, is history. No one was killed, and the building was saved by the sagacious fact of having plenty of windows. Since that first record, of course, there have been many explosions with much loss of life and significant economic consequences.
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  • 40
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    Process Safety Progress 17 (1998), S. 190-195 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The RSST DIERS vent sizing methodology is revised to provide realistic design equations for reactive systems consistent with available large-scale experience. Using easy to obtain RSST data such as rate of temperature rise and rate of pressure rise excellent agreement is illustrated for hybrid, vapor and gassy reactive systems.
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  • 41
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    Process Safety Progress 17 (1998), S. 196-199 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: From the 1960s onwards, the chemical and oil industries developed and used a number of new safety techniques which, in time, became second nature to those who applied them. They included the use of QRA for deciding priorities, Hazop and audits for identifying problems, inherently safer design for avoiding hazards, and more thorough investigation of incidents for identifying underlying causes. However, it has not yet become second nature to remember the accidents of the past and the actions needed to prevent them happening again.I joined industry in 1944 and moved to production in 1952. Then, and for at least 15 years afterwards, safety was a non-technical subject that could be left to arts graduates and elderly foremen. There was concern that people should not be hurt - great attention was paid to the lost-time accident rate - but there was no realization, that it was a subject worthy of systematic study by experienced technologists.This view changed at the end of the 1960s. A new generation of plants had been built, operating at higher temperatures and pressures and containing larger inventories of hazardous chemicals; the result was a series of fires and explosions and a worsening fatal accident rate. Figure 1 shows the situation in ICI, at the time the UK, s largest chemical company. Other companies experienced a similar state of affairs.As a result in 1968, I was appointed one of the company's first technical safety advisers, an unusual appointment at the time for someone with my experience, and if the reason for my appointment had not been so obvious I would have wondered what I had done wrong. I and my colleagues tried to apply the same sort of systematic thinking to safety that we applied in our other professional work. We developed some new concepts and techniques and adopted others. A common feature of our ides, realized only in restrospect, was that they consisted of more than mere problem-solving techniques. Once people had got used to these new concepts and used them a few times, they began to look at a whole range of problems in a different way.
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  • 42
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    Process Safety Progress 17 (1998), S. W3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 43
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    Process Safety Progress 17 (1998), S. 259-262 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Case histories of 65 incidents in runaway reactions and emergency relief in Taiwan were analyzed and classified into several categories according to their causes, materials involved, equipment types, reaction types, and ignition sources. The cases in reactors and storage tanks were examined in more detail owing to the higher probability or larger potential hazard in these two types of equipments. The most common consequence of the incidents are explosions, fires, and atmospheric release of toxic chemicals. The most severe case was a thermal explosion from an organic peroxide storage area which caused the death of 33 persons. Popping and direct releasing of process chemicals to the atmosphere from relieving devices cause the greatest environmental concerns to the community close to the plants. Runaway reactions in batch type reactors occur frequently due to various operational mistakes. Heat of reaction is the most frequent ignition source of runaway reactions and emergency relief.
    Additional Material: 1 Ill.
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  • 44
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    Process Safety Progress 17 (1998), S. 272-277 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: EPA's Risk Management Program regulation, promulgated in June 1996 as 40 CFR Part 68 requires subject industries to submit Risk Management Plans by June 1999. This plan requires hazard assessment of the operations of a facility using worst case scenarios and alternative releases. EPA has provided an Off-site Consequence Analysis (OCA) guidance to help facilities in their hazard assessment.OxyChem will be significantly impacted by the RMP rule. This paper outlines OxyChem's general experience and its strategy in planning to comply with this rule. OxyChem's approach in the development of the scenarios required by the rule is described in this paper. Limitations involved in the use of EPA's look-up tables or a single modeling solution for conducting all of the OCA are discussed. A three tiered OCA approach is presented as a possible alternative.
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  • 45
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    Process Safety Progress 17 (1998), S. 209-212 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: HFC-227ea (CF3CHFCF3;1, 1, 1, 2, 3, 3, 3-heptafluoropropane) is an effective replacement for Halon 1301 in fire suppression systems, providing rapid extinguishment of flames through a combination of physical and chemical mechanisms. The vast majority of applications for HFC-227ea involve the protection of Class A hazards, which are characterized by low fuel loadings and low energy output, with fire sizes often in the range of 5-10 kW. Mid- and large-scale testing has demonstrated that HFC-227ea, at its minimum design concentration of 7.0% v/v, is effective at extinguishing fires typical of those expected to occur in electronic data processing (EDP) facilities, telecommunication facilities and anechoic chambers. The levels of HF produced following extinguishment of typical Class a fires with HFC-227ea were well below the estimated mammalian LC50 and the human Dangerous Toxic Load (DTL), and do not appear to present a threat to electronic equipment.
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  • 46
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    Process Safety Progress 17 (1998), S. 219-224 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sandia National Laboratories (Sandia) has refined a process for developing inherently safer system designs based on methods used by Sandia to design detonation safety into nuclear weapons. The process was created when Sandia realized that standard engineering practices did not provide the level of safety assurance necessary for nuclear weapon operations, with their potential for catastrophic accidents. A systematic approach, which relies on mutually supportive design principles integrated through fundamental physical principles, was developed to ensure a predictably safe system response under a variety of operational and accident-based stesses. Robust, safe system designs result from this thematic approach to safety, minimizing the number of safety critical features. This safety assurance process has two profound benefits: the process avoids the need to understand or limit the ultimate intensity of off-normal environments and it avoids the requirement to analyze and test a large array of accident environment scenarios (e.g., directional threats, sequencing of environments, time races, etc) to demonstrate conformance to all safety requirements.
    Additional Material: 3 Ill.
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  • 47
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    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 48
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    Process Safety Progress 17 (1998), S. 233-237 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new method is described to enhance the management of process safety risks such that the number and type of safety systems protecting against any hazard are consistently predicated upon risk. Further, that such an assignment of safety systems can be made consistent throughout an organization. This consistency is gained through standardization of qualitative risk ranking and by setting company guidelines.
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  • 49
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    Process Safety Progress 17 (1998), S. 243-258 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Research was carried out to develop improved protection guidelines for silane handling systems through enhanced understanding of the behavior of releases of this pyrophoric gas. The approach involved addressing three aspects of the problem: the prompt ignition behavior of silane; the reactivity characteristics of quiescent silane/air mixtures; and the rates of reaction of silane leaked into enclosures with and without explosion venting, in the presence of ventilation air flow. A first conclusion, reached from tests in a ventilated cabinet, was that, contrary to prevailing belief, the ventilation flow has no measurable effect on the prompt ignition of the release. From experiments in a 5.1-liter (311-in.3) sphere it was found that silane/air mixtures of concentrations between 1.4 and 4.1% (by volume) are explosive but stable. In this case, piloted ignition tests yielded laminar burning velocities up to 5 m/s (1000 ft/min). Mixtures between 4.5 and 38% (the maximum reached in the tests) were found to be metastable, and would undergo spontaneous ignition after a delay ranging from 15 to 120 seconds, with the shorter values corresponding to higher silane concentrations. Experiments were also performed in a 0.645-m3 (22.8-ft3) vessel both with and without explosion venting, to measure the rates of energy release associated with impulsively-started silane leaks from 1/8 and 1/4-in. (3.2 and 6.4-mm) lines. A method for the prediction of the venting requirements of partial-volume deflagrations (PVD) was evolved into a tool to quantify the pressure rise from ignition of silane leaks in enclosures. These results represent a significant step toward updating existing design recommendations which prescribe ventilation requirements that are based on outdated and, in some instances, misinterpreted data.
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    Process Safety Progress 17 (1998), S. 278-287 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas explosion simulators are often used as tools in process plant design. This article presents some properties of gas explosions found using the EXSIM simulation software on three offshore modules with a total of nearly 10,000 simulations. The selected results are chosen for their supposed applicability to structural design in the process industries.Generalized data are presented for the effect of gas cloud size, explosion impulse vs. explosion pressure, pressure and impulse vs. duration, the probability of a “short” explosion, loading rate, pressure-time “shape” function, and the effect of introducing louvers.
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  • 51
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1-11 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation of Succinimide During the Synthesis of the Insulin A Chain(14-21) OctapeptideDuring the synthesis of insulin A chain (14-21) fragments it was observed that alkaline treatment of Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut and Msc-Tyr-(But)-Gln-Leu-Glu(OBut)Asn-Tyr(But)-Cys(Trt)-Asn-OBut caused quantitative formation of succinimide in position 21.
    Notes: Bei der Synthese von Teilsequenzen der Insulin-A-Kette (14-21) wurde während der alkalischen Abspaltung der Msc-Gruppe von Msc-Cys(Trt)-Asn-OBut, Msc-Leu-Glu(OBut)-Asn-Tyr(But)-Cys-(Trt)-Asn-OBut und Msc-Tyr-(But)-Gln-Leu-Glu(OBut)-Asn-Tyr(But)-Cys(Trt)-Asn-OBut in allen Fällen Succinimidbildung in Position 21 beobachtet.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 37-48 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, IX. On the Reaction of Amide Acetals with HeterocumulenesDeprotonation of the (dimethylamino)methoxycarbenium ion (10) by NaH liberated the carbene 2, which was trapped by aryl isocyanate to give the hydantoin 6 and by phenyl isothiocyanate to yield 8. Hence, the carbene 2 is assumed to be also an intermediate in the corresponding reactions of the amide acetal 1 which lead to the hydantoins 6 and 8. The reaction of 1 with phenyl isothiocyanate yielded the products 4, 7, 8, or 12 depending on the reaction conditions. An equilibrium between 1 and the carbene 2 is suggested by the reaction of 1 with sulfur to give 16, and is the basis for mechanistic discussions.
    Notes: Das durch Deprotonierung des (Dimethylamino)methoxy-carbenium-Ions (10) mit NaH freigesetzte Carben 2 addierte sich an-Arylisocyanat zum Hydantoin 6, an Phenylisothiocyanat zu 8. Dies legt nahe, daß auch bei der Umsetzung des Amidacetals 1 mit Heterocumulenen zu den Hydantoinen 6 bzw. 8 das Carben 2 beteiligt ist. Bei der Umsetzung von 1 mit Phenylisothiocyanat entstanden je nach Reaktionsführung die Produkte 4, 7, 8 oder 12. Für deren Bildung werden Mechanismen diskutiert, die von einer Gleichgewichtseinstellung von 1 mit dem Carben 2 ausgehen. Diese Annahme wird durch Umsetzung von 1 mit Schwefel zu 16 gestützt.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 67-77 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Perhalomethylthio)heterocycles, VIII. (Perchlorofluoromethylthio)- and (Haloformylthio)-N-heteroaromaticsPyrrole reacts with Cl3-nFnC—SCl (n = 1-3) to give mixtures of 2- and 3-substituted pyrroles 1 a-c and 2a, b; CF3SCFCl—SCl and XC(O)SCl (X = F, Cl) merely yield 2-substituted derivatives 3. In the presence of excess CF3SCl also disubstituted products 4, 5 are available. Analogously pyrrole derivatives can be substituted directly, dependent on their reactivity (6-14). 1a is oxidized by 3-chloroperbenzoic acid to yield the sulfoxide 15 or the sulfone 16; the reaction with bromine and iodine results in the formation of the fully halogenated compounds 17, 18. Indole reacts with CF3SCl to give the 3-substituted 19, while carbazole yields the N-substituted product 20 in a Grignard reaction. 1H and 19F n. m. r. spectra are discussed.
    Notes: Pyrrol setzt sich mit Cl3-nFnC—SCl (n = 1-3) zu Isomerengemischen 2- und 3-substituierter Pyrrole 1a-c bzw. 2a, b, um; CF3SCFCl—SCl und XC(O)SCl (X = F, Cl) liefern lediglich 2-substituierte Derivate 3. In Gegenwart eines CF3SCl-Überschusses sind auch disubstituierte Produkte 4, 5 erhältlich. Analog sind Pyrrol-Derivate, je nach ihrer Reaktivität, einer direkten Substitution zugänglich (6-14). 1 a wird durch 3-Chlorperbenzoesäure zum Sulfoxid 15 bzw. Sulfon 16 oxidiert; die Umsetzung mit Brom bzw. Iod führt zu den vollständig halogenierten Verbindungen 17, 18. Indol reagiert mit CF3SCl zum 3-substituierten 19, während Carbazol in einer Grignard-Reaktion das N-Substitutionsprodukt 20 liefert. 1H- und 19F-NMR-Spektren werden diskutiert.
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  • 54
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 96-106 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Aldehydes and Ketones with the Makosza Dichlorocarbene ReagentPhase transfer-catalyzed reactions of aldehydes and ketones with trichloromethane and 50 per cent aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride (BTEA) at low temperatures result in the formation of α-(trichloromethyl)carbinols 7; in the presence of dimethyl sulfate the corresponding methyl ethers 8 are obtained. At 56 ± 2°C the α-hydroxy-11, α-chloro- 12 and α,β-unsaturated carboxylic acids 13 are formed. In this reaction the α-(trichloromethyl)carbinols 7 can be excluded as intermediates. An alternative reaction mechanism for the formation of 11, 12, and 13 is discussed, which involves direct addition of dichlorocarbene to the C=O double bond to form the dichlorooxiranes 5 followed by rearrangement and saponification.
    Notes: Aldehyde und Ketone reagieren mit Trichlormethan im Zweiphasensystem mit 50proz. wäßrigem Natriumhydroxid unter Phasentransfer-Katalyse durch Benzyltriethylammonium-chlorid (BTEA) (1) bei tiefer Temperatur zu α-(Trichlormethyl)carbinolen 7, in Gegenwart von Dimethylsulfat zu den entsprechenden Methylethern 8. Bei 56 ± 2°C entstehen α-Hydroxy- 11, α-Chlor- 12 und α,β-ungesättigte Carbonsäuren 13, wobei die α-(Trichlormethyl)carbinole 7 als Zwischen-stufen auszuschließen sind. Als Alternativmechanismus wird die direkte Addition von Dichlor-carben an die C=O-Doppelbindung zu Dichloroxiranen 5 und deren Umlagerung und Verseifung diskutiert.
    Additional Material: 2 Tab.
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  • 55
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 56
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 23-36 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, VIII. Selectivity of Nucleophilic Carbenes with Regard to HeterocumulenesThe selectivities of N-methylbenzothiazolinylidene (2) and 1,3-diphenylimidazolidinylidene (3) against aryl isocyanates and phenyl isothiocyanate have been determined. The selectivities increase from dimethoxycarbene (1) over 2 to 3. In contrast all three carbenes display equal selectivity with regard to different aryl isocyanates.
    Notes: Für N-Methylbenzothiazolinyliden (2) und 1,3-Diphenylimidazolidinyliden (3) wurden die Selektivitäten gegenüber verschiedenen Arylisocyanaten einerseits und Phenylisothiocyanat andererseits bestimmt. Diese nehmen vom Dimethoxycarben (1) über 2 zu 3 zu. Dagegen zeigen alle drei Carbene bei 140°C eine übereinstimmende Selektivität gegenüber Arylisocyanaten.
    Additional Material: 3 Ill.
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 12-22 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on Metabolites of Microorganisms, XII. Michigazone, a New Phenoxazone Pigment from Streptomyces michiganensis  -  Structure Determination and SynthesisBy spectroscopic methods and chemical degradation michigazone has been shown to possess structure 7. 7 and some further related phenoxazones have been synthesized by the Kehrmann-method.
    Notes: Spektroskopische Untersuchungen und chemischer Abbau führten für Michigazon zur Konstitution 7. 7 und einige weitere bisher noch nicht beschriebene Phenoxazone wurden durch Kehrmann-Synthese dargestellt.
    Additional Material: 1 Ill.
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 49-52 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbene Reactions, X. Ionic Intermediates in the Reaction of Trimethyl Orthoformate with Aryl IsocyanatesThe ion pair 2/3 is assumed to be the crucial intermediate in the reaction of trimethyl orthoformate with aryl isocyanates. The collapse of the ion pair to 4 is a fast subsequent reaction. The acid base reaction of the ion pair to the carbene 6 proceeds with a comparable rate. Methoxyl transfer of 2/3 to form 1 is considerably slower. Transalkylation of the ion pair to 8 has not been observed.
    Notes: Bei der Umsetzung von Orthoameisensäure-trimethylester mit Phenylisocyanat wird das Ionen-paar 2/3 als zentrale Zwischenstufe angenommen. Eine rasche Folgereaktion dieses Ionenpaares ist die Kombination zu 4. Vergleichbar schnell verläuft die Säure-Basen-Reaktion im Ionenpaar zum Carben 6. Eine Methoxyl-Übertragung aus 2/3 zu 1 ist erheblich langsamer. Die Umalkylierung zu 8 konnte nicht beobachtet werden.
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  • 59
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 86-95 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Activated Ethylenes, V. Reaction of Aromatic Compounds with Derivatives of Chloromethylenemalonic Acid. A new Synthesis of Aromatic AldehydesThe derivatives of chloromethylenemalonic acid 3 and 4 react with aromatic compounds in the presence of aluminium chloride to give the arylmethylenemalonic acid derivatives 5a-i and 6a-d. By hydrolysis of the C=C double bond the corresponding dinitriles 2a-g are converted into aldehydes.
    Notes: Chlormethylenmalonsäure-Derivate 3 und 4 lassen sich in Gegenwart von Aluminiumchlorid mit Aromaten umsetzen, wobei die Arylmethylenmalonsäure-Derivate 5a-i und 6a-d entstehen. Die entsprechenden Dinitrile 2a-g lassen sich durch Hydrolyse der C=C-Doppelbindung in Aldehyde überführen.
    Additional Material: 8 Tab.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 107-123 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemistry of the Norcaradiene-Norcaradiene Rearrangement, I. The Synthesis of Optically Active [Norcaradiene ⇌ Cycloheptatriene] DerivativesAnion 14 derived from treatment of 1,3,5-cycloheptatriene-7-carbonitrile (13) with n-butyllithium or lithium diisopropyl reacts with methyl iodide, deuterium oxide, and carbon dioxide to give the corresponding 7,7-disubstituted derivatives 2, 13-D, and 16. By a sequence of reactions 2 was transformed into the optically pure [norcaradiene ⇌ cycloheptatriene] systems 4 and 10. The equilibrium concentrations of the [norcaradiene ⇌ cycloheptatriene] systems 2-12 were determined by 1H n.m.r. mesurements at low temperatures.
    Notes: Das aus 1,3,5-Cycloheptatrien-7-carbonitril (13) mit n-Butyllithium oder Lithium-diisopropylamid erzeugte Anion 14 reagiert mit Methyliodid, Deuteriumoxid und Kohlendioxid ausschließlich zu den entsprechenden 7,7-disubstituierten Derivaten 2, 13-D, und 16. Aus 2 lassen sich durch eine Folge von Reaktionen die optisch reinen [Norcaradien ⇌ Cycloheptatrien]-Systeme 4 und 10 synthetisieren. Mit Hilfe der Tieftemperatur-1H-NMR-Spektroskopie wurden die Gleichgewichtskonzentrationen der [Norcaradien ⇌ Cycloheptatrien]-Systeme 2-12 ermittelt.
    Additional Material: 3 Ill.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 146-153 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 4-Acetoxy-2-cyclopenten-1-oneBy using 4-acetoxy-2-cyclopenten-1-one (8) as a synthone for the non-existent cyclopentadienone (5), Michael additions are performed that give rise to trans-disubstituted cyclopentanone derivatives (11,12). In the case of tert-butyl acetoacetate as Michael donator the addition to 11 is followed by an aldol-cyclisation to the trans-perhydroazulene system 22.
    Notes: Unter Verwendung von 4-Acetoxy-2-cyclopenten-1-on (8) als Synthon für das nicht existenzfähige Cyclopentadienon (5) wurden Michael-Additionen durchgeführt, die zu trans-disubstituierten Cyclopentanon-Derivaten (11, 12) führen. Bei Verwendung von tert-Butyl-acetacetat als Michael-Donator schließt sich an die Addition zu 11 eine Aldolcyclisierung zum trans-Perhydroazulensystem 22 an.
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  • 62
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 605-610 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with 3,3-Bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. Trapping Reactions of Nitrile Ylides with NitrosobenzeneTrapping reactions of bis(trifluoromethyl)-substituted nitrile ylides 2, generated by thermolysis of 3,3-bis(trifluoromethyl)-Δ4-1,4,2λ5-oxazaphospholines. 1, with nitrosobenzene yield 5,5-bis-(trifluoromethyl)-Δ3-1,2,4-oxadiazolines 3, 3,3-bis(trifluoromethyl)-Δ4-1,2,4-oxadiazolines 4, and 4,4-bis(trifluoromethyl)-1,4-dihydro-1-quinazolinols 5. The compounds 5 are products of a thermal rearrangement of first formed [3 + 2]-cycloadducts. I. r., 1H n. m. r., 19F n. m. r., and mass spectra of the new compounds are described.
    Notes: Abfangreaktionen von bis(trifluormethyl)-substituierten Nitril-yliden 2, die durch Thermolyse aus 3,3-Bis(trifluormethyl)-Δ4-1,4,2λ5-oxazaphospholinen 1 erzeugt werden, mit Nitrosobenzol liefern 5,5-Bis(trifluormethyl)-Δ3-1,2,4-oxadiazoline 3, 3,3-Bis(trifluormethyl)-Δ4-1,2,4-oxadiazoline 4 und 4,4-Bis(trifluormethyl)-1,4-dihydro-1-chinazolinole 5. Die Verbindungen 5 sind das Resultat einer thermisch ausgelösten Umlagerung primär erhaltener [3 + 2]-Cycloaddukte. IR-, 1H-NMR-, 19F-NMR- und Massenspektren der neuen Verbindungen werden beschrieben.
    Additional Material: 4 Tab.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 619-630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXIV. Benzo[12]annulenes: On the Annulene Character of Dibenzo- and Tribenzo[12]annulenesAs a contribution to the controversial discussion about the antiaromaticity of the [12]annulene system in the di- and tribenzo[12]annulenes 3 and 4 the compounds 5, 8, and 18 were prepared for comparison. The discussion of the 1H n. m. r. spectra with consideration of the anisotropy effect of the triple bonds led to the conclusion that in contrast to earlier assumptions the [12]annulene system in 3 and 4 in spite of the benzo-anellation is paratropic.
    Notes: Als Beitrag zu der kontroversen Diskussion über die Antiaromatizität des [12]Annulen-Systems in den Di- und Tribenzo[12]annulenen 3 und 4 wurden die Vergleichsverbindungen 5, 8 und 18 dargestellt. Die Diskussion der 1H-NMR-Spektren unter Berücksichtigung des Anisotropieeffektes der Dreifachbindungen ergab, daß entgegen früherer Auffassung das [12]Annulen-System in 3 und 4 trotz der Benzo-Anellierung paratrop ist.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 631-637 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Conjugation in Macrocyclic Systems, XXV. Benzo[12]annulenes: Synthesis and Properties of a Benzo-naphtho[12]annuleneThe benzo-naphtho[12]annulene 4, where in contrast to 1, 2, and 3 a planar twelve-membered ring is present, has been synthesized via 6-9. 1H n. m. r. absorption of the internal hydrogen is observed at δ = 13.13 ppm. The allotment of this considerable down-field shift to the paratropic effect of the annulene system and the anisotropy of the triple bonds is discussed. For this purpose, the twelve-ring system 5 in which the macrocyclic conjugation is interrupted has been synthesized from 9 via 10 and 11.
    Notes: Das Benzo-naphtho[12]annulen 4, bei dem im Gegensatz zu den Verbindungen 1, 2 und 3 eine ebene Zwölfring-Struktur fixiert ist, wurde über 6-9 synthetisiert. Die 1H-NMR-Absorption des inneren Wasserstoffatoms wird bei δ = 13.13 ppm beobachtet. Die Aufteilung dieser beträchtlichen Tieffeld-Verschiebung in den Paratropie-Effekt des Annulen-Systems und den Anisotropie-Effekt der Dreifachbindungen wird diskutiert. Hierzu wurde das Zwölfring-System 5, bei dem die makrocyclische Konjugation unterbrochen ist, von 9 über 10 und 11 synthetisiert.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 651-655 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XV. Reactions of trans,trans-1,3-Diphenyl-2-azaallyllithium with Heterocumulenestrans,trans-1,3-Diphenyl-2-azaallyllithium (1) reacts with phenylisocyanate, phenylisothiocyanate, and methylisothiocyanate to give an imidazolidine-4-one (2a) or imidazolidine-4-thione (2b, c), respectively. When reacting with carbon disulfide or dicyclohexylcarbodiimide (symmetrical heterocumulenes) the cycloaddition is followed by a fast secondary reaction (→ 4, 7).
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich regiospezifisch an die CN-Doppel-bindung des Phenylisocyanats sowie Phenyl- und Methylisothiocyanats unter Bildung eines Imidazolidin-4-ons (2a) bzw. -4-thions (2b, c). Bei entsprechenden Umsetzungen mit den symmetrischen Heterokumulenen Schwefelkohlenstoff und Dicyclohexylcarbodiimid folgt der Cycloaddition jeweils eine schnelle Sekundärreaktion (→4, 7).
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 667-676 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of trans-[Pt(CO2R)(CO)(PPh3)2]+BF4- with Alkynes: Formation of Alkynyl- and Alkenylplatinum(II) ComplexesThe alkoxycarbonyl complexes [Pt(CO2R)(CO)(PPh3)2]+ BF4- 1 react with alkynes HC≡CR to give the acetylides 2a-c. On the other hand, cationic β-methoxyvinyl 3 or β-hydroxyvinyl complexes 4, respectively, are obtained from the reactions of 1 with disubstituted acetylenes R1C≡CR2 under participation of the nucleophiles methanol and water. Compounds 3 and 4 are converted into neutral derivatives (5, 6, 8) by methoxide or azide ions. The synthesis of Ir(CO2CH3)(CO)(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 is described. Bonding is discussed for the new complexes by means of n. m. r. and i. r. data.
    Notes: Die Alkoxycarbonyl-Komplexe [Pt(CO2R)(CO)(PPh3)2]+BF4- 1 setzen sich mit Alkinen HC ≡ CR zu den Acetyliden 2a-c um. Dagegen entstehen aus 1 und disubstituierten Acetylenen R1C≡CR2 unter Beteiligung der Nucleophile Methanol und Wasser kationische β-Methoxyvinyl- 3, bzw. β-Hydroxyvinyl-Komplexe 4. Die Verbindungen 3 und 4 werden mit Methylat- oder Azid-Ionen in neutrale Derivate (5, 6, 8) umgewandelt. Ferner wird die Synthese von Ir(CO2CH3)(CO)-(CH3O2CC≡CCO2CH3)[P(CH3)Ph2]2 beschrieben. Die Bindungsverhältnisse werden mit Hilfe von NMR- und IR-Daten diskutiert.
    Additional Material: 3 Tab.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 703-716 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Bridged 5,6-Diamino-4,7-dialkyl-1,3-benzodioxoles as Intermediates for the Synthesis of Molecules with Knot StructureIn a reaction sequence involving metalation with butyllithium followed by alkylation. cyclohexanone pyrocatechol acetal 4 is converted to the 3,6-dialkylpyrocatechol 11. By subsequent acetalisation with 1,25-dichloro-13-pentacosanone (14), followed by nitration (19), reduction (20), acylation (26), renewed reduction (27), and cyclization, the double bridged benzodioxole 28 is obtained. The compound represents an intermediate in the projected synthesis of a molecule with knot structure.
    Notes: Ausgehend vom Cyclohexanon-brenzcatechinacetal 4 wird durch Metallierung mit Butyllithium und nachfolgende Alkylierung in einer mehrstufigen Reaktionsfolge das 3,6-Dialkylbrenzcatechin 11 synthetisiert. Durch nachfolgende Acetalisierung mit 1,25-Dichlor-13-pentacosanon (14), gefolgt von Nitrierung (19), Reduktion (20), Acylierung (26), erneuter Reduktion (27) und Cyclisierung wird das zweifach überbrückte Benzodioxol 28 erhalten. Es stellt ein Zwischenprodukt in der geplanten Synthese eines Moleküls mit Knotenstruktur dar.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notes: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 474-486 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 78 Further Constituents of South African Senecio SpeciesFrom representatives of the section Rigidi besides already known compounds four new benzofurans (3, 5, 6, and 10) as well as six new furanoeremophilanes (13, 15, 19-21, and 23) are isolated. From Senecio pterophorus a new type of a pyrrolizidine derivative (25) is isolated. Senecio cissampelinus contains similar compounds (34-37). The structures are elucidated by spectroscopic methods as well as by some chemical reactions. The chemotaxonomical aspects are discussed.
    Notes: Aus Vertretern der Sektion Rigidi werden neben bereits bekannten Verbindungen vier neue Benzofurane (3, 5, 6 und 10) sowie sechs neue Furanoeremophilane (13, 15, 19-21 und 23) isoliert. Aus Senecio pterophorus wird ein neuer Typ eines Pyrrolizidin-Derivats (25) isoliert. Ähnliche Verbindungen (34-37) enthält Senecio cissampelinus. Die Konstitutionen werden durch spektroskopische Methoden sowie durch einige chemische Reaktionen geklärt. Die chemotaxonomischen Aspekte werden diskutiert.
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 491-499 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Monohydrazones of Dicarbonyl Compounds, IV. New Syntheses of Pyrroles and PyrrolinesKetones and aldehydes with an active methylene group condense easily with monohydrazones of glyoxal (1 + 2 → 3). The hydrazonoethylidene derivatives thus obtained can be reduced to give pyrroles, pyrrolines, pyrrolidines, or N-aminopyrroles.
    Notes: Methylenaktive Ketone und Aldehyde lassen sich mit Monohydrazonen des Glyoxals zu Hydrazonoethyliden-Derivaten umsetzen (1 + 2 → 3). Durch Reduktion dieser Produkte sind Pyrrole, Pyrroline, Pyrrolidine sowie N-Aminopyrrole darstellbar.
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 522-539 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 78. Additions of C-(2,2′-Biphenylylene)-Nα-(4-chlorophenyl)-Nβ-cyano-azomethine Imine to Styrene, Alkenes, Enol Ethers and EnaminesThe cycloaddition of the title compound 1 to styrene at 70°C produces 95% of a pyrazolidine; the hydrogenolytic degradation to 9-phenethylfluorene as well as the n. m. r. spectrum reveal the addition direction. The 1-cyanopyrazolidine derivative shows reactions typical for cyanamides. - The azomethine imine 1 likewise accepts many nonconjugated alkenes, cycloalkenes and derivatives of styrene in high yield. The cycloadducts of butyl vinyl ether, cis- and trans-propenyl propyl ether, β-methoxystyrene and vinyl acetate suffer with dilute acids elimination of alkoxide or acetate, respectively, and of the N-cyano group to yield 2-pyrazolines. The electrophilicity of the azomethine imine carbon center determines the addition direction; substituents on the ethylenic dipolarophile which stabilize positive charge in the transition state of cycloaddition show up in position 5 of the pyrazolidine.
    Notes: Die Cycloaddition der Titelverbindung 1 an Styrol bei 70°C ergibt 95% eines Pyrazolidins; die Additionsrichtung geht aus der Hydrogenolyse zu 9-Phenethylfluoren ebenso wie aus dem NMR-Spektrum hervor. Das 1-Cyanpyrazolidin zeigt für Cyanamide typische Reaktionen. - Das Azomethin-imin 1 addiert viele nichtkonjugierte Alkene, Cycloalkene und Derivate des Styrols in hoher Ausbeute, wobei spektroskopische Daten die Addukt-Strukturen sichern. Die Cycloaddukte des Butylvinylethers, cis- und trans-Propenylpropylethers, β-Methoxystyrols und Vinylacetats erleiden schon mit verdünnter Säure eine Eliminierung des Alkoxyls bzw. Acetats und des N-Cyans unter Bildung von 2-Pyrazolinen. Die Additionsrichtung des 1,3-Dipols wird von der Elektrophilie des Azomethin-imin-Kohlenstoffs bestimmt; Substituenten am ethylenischen Dipolarophil, die positive Ladung im Übergangszustand der Cycloaddition zu stabilisieren vermögen, erscheinen in 5-Stellung des Pyrazolidins.
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  • 72
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 611-618 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 2,2,2-Trifluor-4,4,5,5-tetrakis(trifluormethyl)-1,3,2λ5-dioxaphospholanePF5 and PhPF4 react with 2-[bis(trimethylsilyl)amino]-2,2-difluoro-4,4,5,5-tetrakis (trifluoromethyl)-1,3,2λ5-dioxaphospholane (1b) to yield the trifluorophosphorane 2 or 3, respectively. 3 is the first known example of a stable fluorophosphazophosphorane. 2 reacts with methoxytrimethylsilane to give the thermally stable difluoromethoxyphosphorane4; with hexamethyldisiloxane 5 is obtained. PF5 easily converts 5 into 2. Diphenyl(trimethylsilyl)phosphine reduces 2 to the cyclic fluorophosphite 6, which displaces the coordinated cycloolefin in (C7H8)Mo(CO)4 (C7H8 = norbornadiene) with formation of the cis-complex 7. The spectroscopic data are discussed.
    Notes: Die Reaktion von PF5 bzw. PhPF4 mit 2-[Bis(trimethylsilyl)amino]-2,2-difluor-4,4,5,5-tetrakis-(trifluormethyl)-1,3,2λ5-dioxaphospholan (1b) ergibt das Trifluorphosphoran 2 bzw. 3, das erste stabile Fluorphosphazophosphoran. 2 setzt sich mit Methoxytrimethylsilan zu dem thermisch beständigen Difluormethoxyphosphoran 4 um, mit Hexamethyldisiloxan entsteht 5, das mit PF5 leicht in 2 umgewandelt werden kann. Diphenyl(trimethylsilyl)phosphin reduziert 2 zu dem cyclischen Fluorphosphit 6, das in (C7H8)Mo(CO)4 (C7H8 = Norbornadien) das Cycloolefin unter Bildung des cis-Komplexes 7 substituiert. Die spektroskopischen Daten werden diskutiert.
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  • 73
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 638-644 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Anionic Cycloadditions, XIII. endo-exo-Isomeric Cycloadducts of trans,trans-1,3-Diphenyl-2-azaallyllithium and Acenaphthylenetrans,trans-1,3-Diphenyl-2-azaallyllithium adds at O or -70°C to acenaphthylene with retention of configuration to give a mixture of N-lithio-syn- and N-lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrole (3a, 4a, R = Li) (ca. 1:1). The syn-isomer (endo-cycloadduct) rearranges to the anti-isomer (exo-cycloadduct) at +35°C.
    Notes: trans,trans-1,3-Diphenyl-2-azaallyllithium (1) cycloaddiert sich bei O oder -70°C unter Retention an Acenaphthylen zu einem Gemisch von N-Lithio-syn- und N-Lithio-anti-7,9-diphenyl-7,8,9,9a-tetrahydro-6bH-acenaphtho[1,2-c]pyrrol (3a, 4a, R = Li) (ca. 1:1). Das syn-Isomere (endo-Cycloaddukt) lagert sich bei +35°C in das anti-Isomere (exo-Cycloaddukt) um.
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  • 74
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 677-682 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Simple Phosphorus and Arsenic Ylides with Methylgermanium, -tin, and -lead SubstituentsThe syntheses of the ylides (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2, and (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 are reported. The relative substituent effect of all IVb elements on the carbanionic function of ylides is discussed in the light of the 13C and 31P n. m. r. spectra of these compounds and their Si and Sn analogues.
    Notes: Die Darstellung der Ylide (CH3)3P = C[Pb(CH3)3]2, (CH3)3P = C[Ge(CH3)3]2 und (CH3)2-[(CH3)3GeCH2]P = C[Ge(CH3)3]2 wird beschrieben. Der relative Substituenteneffekt aller IVb-Elemente auf die Carbanion-Funktion von Yliden wird an Hand der 13C- und 31P-NMR-Spektren dieser Verbindungen und ihrer Si- und Sn-Analoga diskutiert.
    Additional Material: 1 Ill.
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  • 75
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 717-720 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Alkyl and Aryl Compounds, XIX. Preparation and Crystal Structure of Methylrubidium and MethylcaesiumCH3Rb and CH3Cs are prepared from CH3Li and rubidium tert-butoxide or caesium 2-methyl-2-pentanolate, respectively. As shown by X-ray diffraction of the crystal powders the compounds possess a hexagonal structure of the NiAs type with isolated methyl anions and alkali cations like CH3K investigated earlier.
    Notes: CH3Rb und CH3Cs werden durch doppelte Umsetzung von CH3Li mit Rubidium-tert-butylat bzw. Caesium-2-methyl-2-pentanolat dargestellt. Nach röntgenographischen Untersuchungen der Kristallpulver besitzen die Verbindungen wie das bereits früher untersuchte CH3K eine hexagonale Struktur vom NiAs-Typ mit isolierten Methyl-Anionen und Alkali-Kationen.
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  • 76
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 730-736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometrical Investigations of Dicarbonyl(cyclopentadienyl)(thioamidato) Complexes of Molybdenum and TungstenThe mass spectra of several dicarbonyl(cyclopentadienyl)(thioamidato) complexes of Mo and W and of the corresponding free thioamides are reported and the fragmentation processes are discussed. The fragmentation modes of the ionized complexes reveal structural rearrangements of the organic ligands, which cannot be observed in the spectra of the free thioamides.
    Notes: Die Massenspektren einiger Dicarbonyl(cyclopentadienyl)(thioamidato)-Komplexe von Mo und W und die der zugehörigen freien Thioamide werden angegeben und die Fragmentierungsprozesse diskutiert. Der organische Ligand unterliegt im ionisierten Komplex tiefgreifenden strukturellen Umlagerungen, für die sich in den Spektren der freien Thioamide keine Parallele finden läßt.
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  • 77
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 744-748 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular Interactions of Triple Bonds, XVI. The Crystal and Molecular Structure of 5,6,12,13-Tetradehydro-8,9,10,11-tetrahydro-7H-dibenzo-[a,c]cyclotrideceneThe crystal structure of the title compound was solved by direct methods and has been refined to R = 0.056. The triple bonds are crossed by an angle of 64.0°. Their centres have a distance of 3.174 Å. Because of transannular repulsion within the thirteen-membered ring system the acetylene group deviates by 4.1° and 4.6° respectively in a cisoid manner from a linear arrangement. The other angles are enlarged. In the present conformation the length of the [CH2]5-bridge corresponds the length of the CH2—S—S—CH2-group. The chiral molecule lies on a crystallographic twofold axis.
    Notes: Die Kristallstruktur der Titelverbindung wurde mit direkten Methoden gelöst und bis zu einem R-Wert von 0.056 verfeinert. Die Dreifachbindungen sind unter einem Winkel von 64.0° gekreuzt angeordnet und zeigen einen Mittelpunktsabstand von 3.174 Å. Auf Grund der transannularen Abstoßung innerhalb des dreizehngliedrigen Ringsystems ist die Acetylengruppe um 4.1° bzw. 4.6° aus der linearen Anordnung cisoid deformiert. Die übrigen Winkel sind aufgeweitet. Die Länge der [CH2]5-Brücke entspricht in der vorliegenden Konformation der einer CH2—S—S—CH2-Gruppe. Das chirale Molekül liegt auf einer zweizähligen kristallographischen Achse.
    Additional Material: 1 Ill.
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  • 78
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 693-702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Question of Inner Hexacoordination with Pentaarylphosphoranes; Phosphorane Rearrangements at the Level of Coordination Number 5The spirocyclic pentaarylphosphoranes 13 and 18b containing hydroxy groups in the direct neighbourhood of the molecule centre, isomerize more or less readily to the oxyphosphoranes 14 and 22, resp., with retention of coordination number 5. Inner onium-ate complexations could not be detected with the starting materials.
    Notes: Die spirocyclischen Pentaarylphosphorane 13 und 18b, die in unmittelbarer Nachbarschaft zum Molekülzentrum Hydroxylgruppen aufweisen, isomerisieren mehr oder weniger leicht unter Beibehaltung des Koordinationsniveaus 5 zu den Oxyphosphoranen 14 bzw. 22. Innere Onium-At-Komplexierungen konnten bei den Ausgangsverbindungen nicht nachgewiesen werden.
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  • 79
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 683-692 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1,3,5-Trifluoro-1,3,5-trioxo-1λ6,3λ6,5λ6,2,4,6-trithiatriazine (Sulfanuric Fluoride) with AminesWhereas the reaction of the trithiatriazine 1 with diethylamine yields only mono- and disubstituted derivatives (2b, 3), the reaction with dimethylamine results in the replacement of one, two, or three fluorine atoms (→ 2a, 3a, 4). On the other hand, only mono- or trisubstituted compounds (5a, b or 9a, b, resp.), are formed by the reactions of 1 with primary amines such as methylamine and ethylamine. Ammonia reacts with 1 to give 10·NH3. The free compound 10 is formed by treatment with HCl gas. 10 reacts with P(C6H5)4Cl to yield the ionic compound 11 and with benzaldehyde to form the Schiff base 12. With secondary diamines 1 preferentially undergoes intermolecular linkage with formation of 13, but a bicyclic compound 14 could also be prepared in low yield. 1 reacts with silylamines such as RN(SiMe3)2 (R = CH3, C2H5) only after addition of RNH(SiMe3) (→ 15a, b). Sn—N cleavage reactions with 1 occur more readily. Only monosubstituted products (e. g. 16) are formed. Reaction of 1 with phenylhydrazine results in reduction of a sulfur atom and formation of the anion 17. A substituted anion (18) was also prepared from 2a by this method. The reaction behavior of 1 is discussed in detail.
    Notes: Während das Trithiatriazin 1 mit Diethylamin nur zu Mono- und Disubstitutionsderivaten (2b, 3b) reagiert, kann Dimethylamin ein, zwei oder auch drei Fluoratome austauschen (→2a, 3a, 4). Die Reaktion von 1 mit primären Aminen wie Methylamin und Ethylamin liefert hingegen nur Mono- und Trisubstitutionsprodukte (5a, b bzw. 9a, b). Ammoniak reagiert mit 1 zu 10·NH3, die freie Verbindung 10 entsteht nach Behandeln mit HCl-Gas. Mit P(C6H5)4Cl gibt 10 die ionische Verbindung 11, mit Benzaldehyd die Schiffsche Base 12. Mit sekundären Diaminen setzt sich 1 bevorzugt unter intermolekularer Verknüpfung (13) um, aber auch eine bicyclische Verbindung 14 ist in geringer Ausbeute darzustellen. Mit Silylaminen wie RN(SiMe3)2 (R = CH3, C2H5) reagiert 1 erst nach Zusatz von RNHSiMe3 (→ 15a, b). Sn-N-Spaltungsreaktionen mit 1 verlaufen erheblich leichter, wobei ausschließlich Monosubstitutionsprodukte (z. B. 16) gebildet werden. 1 gibt mit Phenylhydrazin unter Reduktion eines Schwefelatoms das Anion 17. Auch ein substituiertes Anion (18) konnte auf diesem Wege aus 2a dargestellt werden. Das Reaktionsverhalten von 1 wird ausführlich diskutiert.
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  • 80
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the 8-, 4′-, and 7-Monomethyl Ethers of Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavone) and Structure of Ranupenin from Ranunculus repens L.By synthesis of 8-, 4′- and 7-O-monomethylgossypetin via a modified Allan-Robinson condensation as well as directly from gossypetin (3,3′,4′,5,7,8-hexahydroxyflavone), it is shown that ranupenin from Ranunculus repens L., which occurs in the plant as an O-monogalactoside, has the structure not of 8-O-monomethyl- but of 7-O-monomethylgossypetin.
    Notes: Durch die Synthese von 8-, 4′- und 7-O-Monomethylgossypetin über eine modifizierte Allan-Robinson-Kondensation bzw. direkt aus Gossypetin (3,3′,4′,5,7,8-Hexahydroxyflavon) konnte geklärt werden, daß dem als O-Monogalactosid natürlich vorliegenden Ranupenin aus Ranunculus repens L. nicht die Konstitution eines Gossypetin-8-, sondern -7-methylethers zukommt.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 773-777 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Mechanics Calculations on the Stability of Bridgehead OlefinsEmpirical force field calculations were used to determine the limits of application of the rules proposed by Fawcett Wiseman and Köbrich for the stability of bridgehead olefins (Bredt compounds). The stability is ruled by the size of the trans-cycloolefin unit, whereas the sum of the number of atoms in the three bridges is of minor importance. With a given skeleton the double bond was found less favourable in the largest bridge than in the second largest in most cases studied.
    Notes: Mittels empirischer Kraftfeldrechnungen wird der Gültigkeitsbereich der Regeln von Fawcett, Wiseman und Köbrich zur Vorhersage der Stabilität von Brückenkopfolefinen (Bredt-Verbindungen) untersucht. Die Größe der trans-Cycloolefineinheit ist für die Stabilität ausschlaggebend, die Summe der Ringgliederzahl in den drei Brücken ist von untergeordneter Bedeutung. Bei gegebenem Gerüst ist in der Mehrzahl der untersuchten Moleküle die Doppelbindung in der größten Brücke weniger günstig als in der zweitgrößten.
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  • 82
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 816-819 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Borabenzene Derivatives, IX. Paramagnetic Chromium Complexes of 1-Methylborinate and 1-Phenylborinate IonsPotassium borinates, K[C5H5B-R] (R = CH3, C6H5), react with CrCl3 or CrCl2·THF to give paramagnetic bis(borinato)chromium complexes, Cr(C5H5B-R)2 (R = CH3, C6H5). For these a sandwich structure with a 16-electron valence shell is proposed.
    Notes: Durch Umsetzung von Kaliumborinaten, K[C5H5B-R] (R = CH3, C6H5), mit CrCl3 oder CrCl2·THF werden paramagnetische Bis(borinato)chrom-Komplexe, Cr(C5H5B-R)2 (R = CH3, C6H5), erhalten. Für diese wird eine Sandwich-Struktur mit einer 16-Elektronen-Valenzschale vorgeschlagen.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 994-999 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Reactions of Hydroxy-N,N-dimethylcarboxamides3-Hydroxy-N,N-dimethyl-1-carboxamides (2, 7) are converted into the corresponding γ-butyrolactones (3, 8) by treatment with an acidic ion-exchange resin in acetone or by thermolysis. 2-Hydroxy-N,N-dimethyl-1-carboxamides (10, 12, 14, 16b, 18) on the contrary form the corresponding carbonyl compounds (9, 11, 13, 15b, 17).
    Notes: 4-Hydroxycarbonsäure-dimethylamide (2, 7) lassen sich durch Behandlung mit saurem Ionenaustauscher in Aceton oder durch Thermolyse in die entsprechenden γ-Butyrolactone(3,8) überführen. 3-Hydroxycarbonsäure-dimethylamide (10, 12, 14, 16b, 18) bilden hingegen beim Erwärmen die entsprechenden Carbonylverbindungen (9, 11, 13, 15b, 17) zurück.
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  • 84
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Chemistry of Reactive Organic Compounds, XIV. The Reactions of Aliphatic Diazo Compounds with the Tricarbonyl(cyclopentadienyl) Hydrides of Molybdenum and TungstenDepending on their constitution, aliphatic diazo compounds 3 behave differently in their reactions with tricarbonyl(cyclopentadienyl)hydridomolybdenum (1) and -tungsten (2). Diazomethane (3a), diazoethane (3b), and 2-diazopropane (3c) are stabilized as alkane diazo ligands in complexes of the type C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7). Phenyl-, (4-nitrophenyl)-, (4-methoxyphenyl)diazomethane (3d, e, f), and 9-diazofluorene (3g) form in clean reactions the carbene insertion products C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), whereas ω-diazoacetophenone (3h) and diazodimedone (3i) yield the binuclear diazo complexes C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10). Diethyl diazomalonate (3h) is coordinated as an imino-amido ligand in the coordination compound 14 which arises from a 1,1-insertion of 3k into the polar tungsten-hydrogen bond of 2.
    Notes: In ihrer Reaktivität gegenüber Tricarbonyl(cyclopentadienyl)hydridomolybdän (1) und -wolfram (2) weisen Diazoalkane 3 starke konstitutionsbedingte Unterschiede auf: Diazomethan (3a), Diazoethan (3b) und 2-Diazopropan (3c) werden als Alkandiazo-Liganden in Komplexen vom Typ C5H5M(CO)2[N2CHR1R2] (M = Mo: 6; M = W: 7) stabilisiert; Phenyl-, (4-Nitrophenyl)-, (4-Methoxyphenyl)diazomethan (3d, e, f) sowie 9-Diazofluoren (3g) bilden in glatten Reaktionen die Carben-Insertionsprodukte C5H5M(CO)3CHR1R2 (M = Mo: 4; M = W: 5), während ω-Diazoacetophenon (3h) wie auch Diazodimedon (3i) die zweikernigen Diazoketon-Komplexe C5H5M(CO)3-M(CO)2C5H5[N2 = CR1R2] (M = Mo: 9; M = W: 10) ergeben. Diazomalonsäure-diethylester (3k) wird im Zuge einer zur Koordinationsverbindung 14 führenden 1,1-Insertion in die polare Wolfram-Wasserstoff-Bindung von 2 als Imino-amido-Ligand komplexiert.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 948-953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XXI. On Dehydro Amino Acids, VIII. N-Acyl-α,β-dehydro Amino Acids by Rearrangement of N-Acyl-α-imino AcidsAcetylation of 2-iminoisovaleric acid ester 1 gives the acetyl imino derivative 2. By addition of nucleophilic reagents the α-substituted valine esters 5 and 6 are obtained; base catalyzed rearrangement affords acetyl-α,β-dehydrovaline ester 7. The latter reaction opens a general approach to Boc-α,β-dehydroamino acids 11a-d and esters 9a-d.
    Notes: Durch Acetylierung von 2-Iminoisovaleriansäureester 1 wird die Acetyliminoverbindung 2 erhalten. Addition von nucleophilen Reagentien führt zu den α-substituierten Valinestern 5 und 6, basenkatalysierte Umlagerung zu Acetyl-α,β-dehydrovalinester 7. Letztere Reaktion eröffnet einen allgemeinen Weg zu Boc-α,β-Dehydroaminosäuren 11a-d und ihren Estern 9a-d.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 979-984 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Natural Dibenzo-α-pyrones, II. Synthesis of Alternariol and Alternariol 9-Methyl EtherThe synthesis of 3,7,9-trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-one (alternariol, 1) and the first synthesis of its 9-methyl ether (2) as well as an extension of the Hurtley condensation to o-bromobenzamides are reported.
    Notes: Die Synthese von 3,7,9-Trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-on (Alternariol, 1), die erste Synthese von Alternariol-9-methylether (2) und eine Erweiterung der Hurtley-Kondensation auf o-Brombenzamide wird beschrieben.
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  • 87
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1020-1026 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonylchlorobis(tri-tert-butylphosphine)rhodium(I)Tri-tert-butylphosphine reacts with tetracarbonyl-μ-dichlorodirhodium (1) to form carbonylchlorobis(tri-tert-butylphosphine)rhodium(I) (2), existing in an equilibrium with dicarbonyl-μ-dichlorobis(tri-tert-butylphosphine)dirhodium (3) in pentane solution, which can be seen in the i. r. and 31P-n. m. r. spectra. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 4 molecules in a unit cell of symmetry P21/n in the monoclinic system.
    Notes: Tri-tert-butylphosphin reagiert mit Tetracarbonyl-μ-dichlorodirhodium (1) unter Bildung von Carbonylchlorobis(tri-tert-butylphosphin)rhodium(I) (2), das in Pentanlösung mit Dicarbonyl-μ-dichlorobis(tri-tert-butylphosphin)dirhodium (3) im Gleichgewicht steht, was sich im IR- und 31P-NMR-Spektrum verfolgen läßt. Die Kristallstruktur von 2 wurde röntgenographisch aus Diffraktometer-Einkristalldaten bestimmt. Die Verbindung kristallisiert mit 4 Molekülen in der Elementarzelle der Symmetrie P21/n im monoklinen System.
    Additional Material: 4 Tab.
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  • 88
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1042-1046 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stable Mercury(I)-Sulfur Compounds, 3. Investigations on the Donor Capacity of Sulfur at the Mercury(I) IonNew mercury(I)-sulfur compounds have been prepared by reactions between mercury(I) nitrate, perchlorate or hexafluorosilicate solutions with methanol, water/benzene or water/methylene chloride solutions of the following sulfur donor ligands: 1,3-dithiolane, 2-phenyl-1,3-dithiolane, 2,2′-trimethylenebis(1,3-dithiolane), bis(benzylthio)methane, dibenzylsulfide. With mercury(I)-dinitrate, the products are the 1:1 adducts (1a), (4a), (6a), and (11a). With mercury(I)-perchlorate the 1:2 adducts (1b),(4b),(6b) or the 1:1 adducts (5b) and (11b) have been obtained. Dibenzylsulfide forms a 1:1 adduct (11c) with dimercury(I)-hexafluorosilicate.
    Notes: Neue Quecksilber(I)-Schwefel-Verbindungen wurden durch Umsetzung von Quecksilber(I)-nitrat, -perchlorat bzw. -hexafluorosilicat-Lösungen mit folgenden Schwefel-Donor-Liganden in methanolischen Lösungen bzw. im Zweiphasensystem wäßrige Lösung/Benzol oder Methylenchlorid hergestellt: 1,3-Dithiolan, 2-Phenyl-1,3-dithiolan, 2,2′-Trimethylenbis(1,3-dithiolan), Bis-(benzylthio)methan, Dibenzylsulfid. Mit Quecksilber(I)-nitrat werden 1:1-Addukte (1a), (4a), (6a) und (11a), mit Quecksilber(I)-perchlorat 1:2-Addukte (1b), (4b) und (6b) bzw. 1:1-Addukte (5b) und (11b) erhalten. Mit Diquecksilber(I)-hexafluorosilicat bildet das Dibenzylsulfid ein 1:1-Addukt (11c).
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  • 89
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1069-1085 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Reactions of Thiacyclanone-1,1-dioxides with DiazoalkanesThiacyclanone-1,1-dioxides 1a-e, 9, 13, 15a react with diazomethane and diazoethane to give the enol ethers 2a-j, epoxides 4c, h, 10a, 14a, 17a, α-alkyl-β-ketosulfones 3d, e, j, and ring-enlarged ketosulfones 5h, i, 7h, 11b, 12b, 15b, 16b and 18a, depending on the size of the ring and the position of the carbonyl and sulfonyl group to each other. The enol ethers are easily hydrolysed with mineral acids forming the β-ketosulfones 1a-e. In the presence of lewis acids ethyl diazoacetate yields ethoxycarbonylmethoxy compounds 2k, I, and ring-enlarged β-ketoesters 5k-o, 7m, n, 15c, 16c, and 18c. Only the γ-ketosulfone 9 with ethyl diazoacetate gives, in addition to the ring-enlarged product 11c, the glycidic ester 10c. The β-ketoesters undergo hydrolysis and decarboxylation to the ketosulfones in very good yield. In the ring-expansion of ketosulfones with diazoethane and ethyl diazoacetate the preferred insertion of the diazo compound occurs between the C-3 and C-4 atoms.
    Notes: In Abhängigkeit von der Ringgliederzahl und der Lage von Carbonyl- und Sulfonylgruppe zueinander reagieren Thiacyclanon-1,1-dioxide 1a-e, 9, 13 und 15a mit Diazomethan bzw. -ethan zu Enolethern 2a-j, Epoxiden 4c, h, 10a, 14a, 17a, α-Alkyl-β-ketosulfonen 3d, e,j oder zu ringerweiterten Ketosulfonen 5h,i, 7h, 11b, 12b, 15b, 16b und 18a. Die Enolether spalten leicht mit Mineralsäure zurück zu den β-Ketosulfonen 1a-e. Mit Diazoessigester in Gegenwart von Lewis-Säuren entstehen die Ethoxycarbonylmethoxy-Verbindungen 2k, I bzw. die ringerweiterten β-Ketoester 5k-o, 7 m, n, 15c, 16c und 18c; lediglich das γ-Ketosulfon 9 gibt mit Diazoessigester neben dem Ringerweiterungsprodukt 11c den Glycidester 10c. Die β-Ketoester lassen sich in guten Ausbeuten zu den Ketosulfonen verseifend decarboxylieren. Bei den Ringerweiterungen der Ketosulfone mit Diazoethan und Diazoessigester ist eine bevorzugte Insertion des Diazoalkanrestes zwischen C-3 und C-4 festzustellen.
    Additional Material: 2 Tab.
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  • 90
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1124-1129 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Four- and Five-membered Phosphorus Heterocycles, 15. The Products of Carbohydrazide/Phosphonic Chloride Reaction: 2,2′-Spirobi(1,3,4,2λ5-oxadiaza-phospholines)The products of the 2:1-condensation of carbohydrazides 1 with phosphonic dichlorides 2 are not cyclic anhydrides 4 of the phosphonic bis(acylhydrazides), as has been assumed until now. Instead they possess the structure of the spirocyclic phosphoranes 9 named in the title. Their formation is due to the unusual reaction of a P = O-bond involving elimination of water. With dimethylphosphinic chloride (14) the hydrazides 1 react in quite the same sense to give the dimers 17 of oxadiazaphospholes in which the pentacoordinate phosphorus (as a bridgehead) is again part of two small rings. The phosphoranes 9 are also obtained from the reaction of 1 with tetrachloro-phosphoranes 5 or thiophosphonic dichlorides 18 or even bis(dimethylamino)phosphines 19.
    Notes: Die 2:1-Kondensationsprodukte aus Carbonsäurehydraziden 1 und Phosphonyldichloriden 2 stellen nicht - wie bisher angenommen - durch Anhydridbildung cyclisierte Phosphonsäure-bis(acylhydrazide) 4 dar, sondern die im Titel genannten spirocyclischen Phosphorane 9. Ihr Entstehen beinhaltet das „Aufrichten“ einer P = O-Bindung unter Wasserabspaltung. Mit Di-methylphosphinylchlorid (14) reagieren die Hydrazide 1 im gleichen Sinn zu Oxadiazaphosphol-Dimeren 17 mit ebenfalls bicyclisch (als Brückenkopf) eingebautem Phosphoranphosphor. Die Phosphorane 9 entstehen auch aus 1 und Tetrachlorphosphoranen 5 oder Thiophosphonyl-dichloriden 18 oder auch Bis(dimethylamino)phosphinen 19.
    Additional Material: 1 Tab.
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  • 91
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1684-1690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Hydronium Tetrachloroaurate(III)-2,2-dimethyl-2H-benzimidazole 1,3-Dioxide, (C9H10N2O2)H3O+ [AuCl4]-1,2-Benzoquinone dioxime (1) reacts with tetrachlorogold(III) acid-trihydrate in dialkyl ketones as solvents to yield solids 5-7 which contain H3O+ and [AuCl4]- ions and neutral 2,2-dialkyl-2H-benzimidazole 1,3-dioxides (2-4). The organic, neutral molecule can easily be isolated from this solid by means of an ion-exchanger. The structure of hydronium tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazole 1,3-dioxide (5), which can be obtained from acetone solutions, is obtained by X-ray analysis.
    Notes: Die Reaktion von 1,2-Benzochinondioxim (1) mit Tetrachlorogold(III)-säure-trihydrat in Dialkyl-ketonen als Lösungsmittel führt zu Festkörpern 5-7, die aus H3O+- und [AuCl4]--Ionen sowie aus neutralen 2,2-Dialkyl-2H-benzimidazol-1,3-dioxiden (2-4) aufgebaut sind. Daraus läßt sich das organische neutrale Molekül mittels eines Ionenaustauschers abtrennen und in Substanz isolieren. Die Struktur des aus Aceton erhältlichen Hydronium-tetrachloroaurat(III)-2,2-dimethyl-2H-benzimidazol-1,3-dioxids (5) wird durch Röntgenstrukturanalyse ermittelt.
    Additional Material: 1 Ill.
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  • 92
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1744-1747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Photochemistry of Two Tribenzo-(CH)12-Valence IsomersA new synthesis of the tribenzo[12]annulene 1 and the photochemical transformations of 1 and of its valence isomer 2 are described. A reaction mechanism is proposed.
    Notes: Eine neue Synthese des Tribenzo[12]annulens 1 und die photochemischen Umwandlungen von 1 und seines Valenzisomeren 2 werden beschrieben. Ein Reaktionsmechanismus wird vorgeschlagen.
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  • 93
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1759-1762 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naturally Occurring Terpene Derivatives, 94. New Furanoeremophilanes from Ligularia vorobierii Worosh.L. vorobierii contains besides already known five new furanoeremophilane derivatives (5 and 7-10). Their structures have been elucidated by spectroscopic methods. The constituents show again a close relationship to the neighbouring genus Senecio.
    Notes: L. vorobierii enthält neben bereits bekannten fünf neue Furanoeremophilan-Derivate (5 und 7-10), deren Konstitutionen durch spektroskopische Methoden geklärt werden. Die Inhaltsstoffe zeigen erneut eine enge Verwandtschaft zu der Nachbargattung Senecio.
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  • 94
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
    Additional Material: 3 Ill.
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  • 95
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1833-1851 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Double Metallation of Benzyl- and Allylmercaptanes; the Thiobenzaldehyde and Thioacrolein DianionsDouble deprotonation of benzyl, allyl and 2-methylallyl mercaptane furnishes thiocarbonyl dianiones 2, 12, and 15, respectively. The novel nucleophiles react with alkyl halides, epoxides, and carbonyl derivatives to give good yields of products of type 3, 13/14, and 16/17, respectively. The doubly lithiated allyl mercaptanes are preferentially attacked by all of the employed electro-philes in the γ-position (60/40-90/10 γ/α-ratio) to lead to cis-vinyl sulfides 13 and 16. These can be converted into sulfur-free propanal derivatives 22-26 in high yields. 12 resembles synthetically the otherwise not available 3-lithiopropionaldehyde (18′, homoenolate).
    Notes: Thiocarbonyl-Dianionen lassen sich quantitativ durch doppelte Deprotonierung aus Benzyl-(→2), Allyl- (→12) und 2-Methylallylmercaptan (→15) erzeugen. Die neuen Nucleophile setzen sich mit Alkylhalogeniden, Epoxiden und Carbonylverbindungen in guten Ausbeuten zu Produkten vom Typ 3, 13/14 bzw. 16/17 um. Die doppelt metallierten Allylmercaptane reagieren mit allen bisher getesteten Elektrophilen bevorzugt in γ-Stellung (60/40—90/10 für γ/α) zu cis-Vinyl-sulfiden 13 und 16, die in guten Ausbeuten in schwefelfreie Propionaldehydderivate 22-26 übergefuhrt werden konnten. 12 entspricht damit synthetisch dem nicht direkt zugänglichen 3-Lithio-propionaldehyd (18′, Homoenolat).
    Additional Material: 4 Tab.
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  • 96
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1896-1907 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Branched-chain Sugars, XV. Glycoside Syntheses with L-StreptoseThe halogeno derivatives of the cyclic carbonates 11 a and 11 b are most suitably used in the synthesis of L-streptose β-glycosides. α-Glycosides are obtained from the benzylidene compound 20. The benzylidene group can be subsequently removed by catalytic hydrogenation. Using the glycosyl halide 16 a also α-glycosides are formed in high yields. However, it is difficult to cleave the isopropylidene group under acidic conditions. Acetylated halides of type 4 are very labile and therefore not useful in glycoside synthesis.
    Notes: Zur Herstellung β-L-glycosidischer Verknüpfungen der L-Streptose sind die Halogenide des cyclischen Carbonats 11 a und 11 b am besten geeignet. α-L-Glycosidische Verknüpfungen der L-Streptose werden am günstigsten mit der Benzylidenverbindung 20 erhalten. Die Benzylidengruppe ist anschließend hydrogenolytisch abspaltbar. Auch das Halogenid 16 a liefert hohe Anteile an α-Glycosid. Die Isopropylidengruppe ist aber schwierig sauer abspaltbar. Acetylierte Halogenide wie 4 sind wegen ihrer Empfindlichkeit zur Glycosidsynthese weniger geeignet.
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  • 97
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1925-1930 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, VI. Synthesis of StreptobiosamineA synthesis of 5-deoxy-2-O-(2-deoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-streptobiosamine) is described. The same synthesis was repeated with the corresponding L-sugars. It leads to 5-deoxy-2-O-(2-deoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-streptobiosamine), the disaccharide portion of streptomycin.
    Notes: Eine Synthese der 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-D-glucopyranosyl)-3-C-formyl-D-lyxofuranose (11) (D-Streptobiosamin) wird beschrieben. Die gleiche Synthese wurde auch mit den entsprechenden L-Zuckern durchgeführt. Sie lieferte 5-Desoxy-2-O-(2-desoxy-2-methylamino-α-L-glucopyranosyl)-3-C-formyl-L-lyxofuranose (1) (L-Streptobiosamin), das den Disaccharidbaustein des Streptomycins darstellt.
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  • 98
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1971-1977 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XIV. The Catalysed Reaction of Aldehydes with Mannich BasesAlkali cyanide- and thiazolium salt-catalysed addition of aldehydes to Mannich bases of saturated and unsaturated ketones leads to the formation of 1,4-diketones (1-6, 9-22).
    Notes: Alkalicyanid- und thiazoliumsalz-katalysierte Additionen von Aldehyden an Mannich-Basen von gesättigten und ungesättigten Ketonen führen zu 1,4-Diketonen (1-6, 9-22).
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  • 99
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mechanism of the Aluminium Chloride-catalysed Rearrangement of 7 H-Dibenzo[c,g]carbazole to 7 H-Dibenzo[a,g]carbazole and of Related Aromatic Skeleton RearrangementsOn an experimental basis a mechanism for the aluminium chloride-catalysed rearrangement of 7 H-dibenzo[c,g]carbazole (1) to 7 H-dibenzo[a,g]carbazole (2) is derived, that involves in the first step formation of the 5,6-dihydro derivatives 3 and 9 which rearrange via a spiro cation 14. This mechanism should also be valid for topologically analogous systems.
    Notes: Für die aluminiumchlorid-katalysierte Skelettumlagerung von 7 H-Dibenzo[c,g]carbazol (1) in 7 H-Dibenzo[a,g]carbazol (2) wird aus Experimenten ein Mechanismus abgeleitet, nach dem zunächst Bildung der 5,6-Dihydro-Derivate 3 und 9 erfolgt, die über ein Spirokation 14 umlagern. Dieser Mechanismus sollte auch für topologisch analoge Systeme zutreffen.
    Additional Material: 1 Tab.
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  • 100
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2019-2027 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclophosphates, III. Synthesis and Properties of Uridine 3′,5′-Cyclophosphate EstersThe uridine 3L′,5′-cyclophosphate esters 4-11 were synthesized by reaction of the free acid of uridine 3′,5′-cyclophosphate (1-3) with the appropriate diazoalkane. The configuration of the isomeric 1,3,2λ5-dioxaphosphorinanes is assigned on the basis of an X-ray analysis with the aid of 31P n. m. r. The stereoselectivity was influenced in part by the degree of reactivity of the diazo compound, by steric hindrance in the 2′-position of the ribose, and by variation in the reaction temperature. The newly synthesized compounds were characterized by u. v. and 31P n. m. r. spectra.
    Notes: Die Uridin-3′,5′-cyclophosphat-ester 4-11 wurden durch Reaktion der freien Säure des Uridin-3′,5′-cyclophosphates (1-3) mit den entsprechenden Diazoalkanen erhalten. Die Zuordnung der stereoisomeren 1,3,2λ5-Dioxaphosphorinane läßt sich mit Hilfe der 31P-NMR-Spektren aufgrund einer Röntgenstrukturanalyse zeigen. Eine stereoselektive Beeinflussung durch Variation der Reaktivität der Diazokomponente oder durch sterische Hinderung an der 2′-Position der Ribose, sowie in Abhängigkeit von der Temperatur, konnte partiell erzielt werden. Sämtliche synthetisierten Verbindungen wurden durch UV- und 31P-NMR-Spektren charakterisiert.
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