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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 61-67 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 98-103 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 20-22 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 39-42 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 49-60 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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].
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 68-73 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 9-15 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 23-31 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 32-38 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 124-126 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 138-148 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. F3 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 157-170 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 200-208 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 213-218 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 238-242 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 263-271 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 288-296 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 297-301 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 83-85 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 1-8 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 15 Ill.
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  • 26
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 16-19 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 43-48 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
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  • 28
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 74-81 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 104-106 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
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  • 31
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 107-123 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 149-154 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 176-183 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 35
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 86-97 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 15 Ill.
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  • 36
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 134-137 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
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  • 37
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 127-133 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
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  • 38
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 171-175 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
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  • 39
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 184-189 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 190-195 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 9 Ill.
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  • 41
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 196-199 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
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  • 42
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. W3 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 259-262 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
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  • 44
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 272-277 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Tab.
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  • 45
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 209-212 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
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  • 46
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 219-224 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
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  • 47
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 233-237 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 243-258 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 15 Ill.
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  • 50
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Process Safety Progress 17 (1998), S. 278-287 
    ISSN: 1066-8527
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 51
    ISSN: 0009-2940
    Schlagwort(e): Manganese-mediated cyclization ; Nine-membered carbocycles ; Manganese complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Photochemical Reactions of Transition Metal Organyl Complexes with Olefines, 31). - [4 + 5] Cycloaddition of Conjugated Dienes to Tricarbonyl(η5-2,4-dimethyl-2,4-pentadienyl)manganeseTricarbonyl(η5-2,4-dimethyl-2,4-pentadienyl)manganese [1] reacts photochemically with the acyclic conjugated dienes 1,3-butadiene [A], 2-methyl-1,3-butadiene [B], (E)-1,3-pentadiene (C), (E,E)-2,4-hexadiene (D), 2,4-dimethyl-1,3-pentadiene (E), 2,4-hexadien-1-ol (F), and methyl 2,4-hexadienoate (G) in a formal [4 + 5] cycloaddition to give tricarbonylmanganese complexes with η3:2-2,6-cyclononadien-1-yl ligands (2A-2G). In addition, the reaction of 1 with A yields thermolabile [η3:2:2-1-(3-butene-1,2-diyl)-1,3-dimethyl-2,6-cyclononadiene]dicarbonylmanganese (3A) and E,E and E,Z isomers of [η3-1-(2-butene-1,1-diyl)-1,3-dimethyl-2,6-cyclononadiene]tetracarbonylmanganese (4A, 4A] as byproducts. Similarly, 1 reacts with B to form tetracarbonyl[η3-1-(3-methyl-2-butene-1,1-diyl)-1,3,6-trimethyl1-2,6-cyclononadiene]manganese (4B) in a side reaction. The crystal and molecular structures of tricarbonyl(η3:2-1,3,5,5,7-pentamethyl-2,6-cyclononadien-1-yl]manganese (2E) and of 3A are determined by X-ray structure analyses. In each of the formally octahedral complexes unusual long manganese-carbon bonds are found for one coordinated CC double bond of the hydrocarbon ligands.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 17-23 
    ISSN: 0009-2940
    Schlagwort(e): (Borole)nickel complexes ; Nucleophilic substitution at boron ; 1H-Borole ; Dihydro-1H-borolediide ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Derivatives of Borole, XVI1), - Bis(borole)nickel Complexes2)The dilithium 1-(dialkylamino)dihydroborolediides Li2[C4H4-BNR2] 2a, b: R = Me, Et) react with NiCl2 · DME to give bis(borole)nickel complexes Ni(C4H4BNR2)2. Nucleophilic substitution reactions are used to produce a large variety of derivatives Ni(C4H4BR)2 1 (e.g. R = H, tBu, F, Cl, Br, I, OH, OMe). Treatment of Ni(C4H4BCl)2 (tg) with LiO(CH2)3OLi in THF produces a polymer and a dinuclear complex (μ-{η5:η5-[(CH2)3(OBC4H4)2]}2Ni2 (3) which crystallizes from CH2Cl2 as solvate 3 · CH2Cl2. The complexes 1g and 3 · CH2Cl2 are characterized by X-ray diffraction work. Barriers to internal ring-ring rotation are measured by variable-temperature NMR spectroscopy. The B - H bond of Ni(C4H4BH)2 (1a) is remarkably inert and does not react with H2O or with carboxylic acids in THF at room temperature. With PhCHO slow formation of the benzyloxy compound Ni(C4H4BOCH2Ph)2 (1 m) is observed at 100°C. For typical complexes such as the phenyl derivative 1e cyclic voltammetry in CH2Cl2 reveals an irreversible oxidation at 1.32 and a quasi-reversible reduction at -1.37 V vs. SCE.
    Zusätzliches Material: 1 Ill.
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  • 53
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 25-29 
    ISSN: 0009-2940
    Schlagwort(e): Borole complexes ; {η5-[1-(Diisopropylamino)borole]}metal complexes, internal rotation of, protonation of ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Derivatives of Borole, XVII1). - {η5-[1-(Diisopropylamino)borole]}metal Complexes: Syntheses, Protonation, Internal RotationNew complexes M(CO)4L (M = Cr, W), cis-M(CO)2L2 [M = Mo, W (not isolated)], and (COD)NiL have been prepared from the Diels-Alder dimer L2, where L is 1-(diisopropylamino)borole, C4H4BNiPr2. Complexes of L can be protonated at the nitrogen atom to give stable salts such as [Cr(CO)4(LH)]BF4, [Fe(CO)3(LH)]BF4, [(C6Me6)Ru(LH)]BF4, and [CpCo(LH)]BF4; B  -  N bond dissociation is not observed. Barriers to internal rotation have been determined by variable temperature NMR spectroscopy for Cr(CO)4L, (COD)NiL, and NiL2. Three processes have been identified: rotation of the NiPr2 group around the B  -  N bond, gear-mesh rotation of the isopropyl groups around the C  -  N bonds, and rotation of L with respect to the counter ligands.
    Zusätzliches Material: 1 Ill.
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  • 54
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 51-61 
    ISSN: 0009-2940
    Schlagwort(e): Selenocarbonyl compounds, perfluorinated ; 1,3-Diselenetanes, perhalogenated ; 2-Selenabicyclo[2.2.1]hept-5-enes ; 1,3-Diselenetan-2-ylium hexafluoroarsenates ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Preparation of (Perfluoroalkyl)halogeno-1,3-diselenetanes from the Corresponding Selenocarbonyl Fluorides and Reactions with Boron Trichloride or Arsenic Pentafluoride1)Reactions of Hg(SeRt)2 (Rt = C2F5, C3F7, CF3) with (C2H5)2 All or All3 in octamethylcyclotetrasiloxane produce the unstable perfluoroalkaneselenocarbonyl fluorides 1 [R1 = CF3 (1 a), C2F5 (1 b), CF3Se (1 c)]. These compounds are very reactive and polymerize to rubberlike products. On heating the polymers decompose almost quantitatively to the monomers or dimers. In CFCl3 solution 1 dimerizes at 20°C in sunlight to the corresponding cis/trans-1,3-diselenetanes 2. The structure of 2 b is determined by single crystal X-ray diffraction. Different selenocarbonyl derivatives add to unsymmetrically substituted 1,3-diselenetanes 3. 1 a and 1 b react with cyclopentadiene to form the [4 + 2] cycloaddition products 4a and 4c. Halogen exchange reactions take place between 2a  -  d and BCl3. The cis-isomers react much faster than the trans-isomers to give a mixture of cis-, trans-forms of 5. When 2c,d is treated with BCl3 it is possible to isolate and characterize the pure trans-isomer 2d, which is separated by preparative gas chromatography from 5c,d. Fluorine abstraction with formation of 1,3-diselenetan-2-ylium ions (6a  -  f) are accomplished by reactions of 2 or 3 with AsF5 in SO2.
    Zusätzliches Material: 1 Ill.
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  • 55
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 87-88 
    ISSN: 0009-2940
    Schlagwort(e): Alkylidenesulfur difluoride oxide ; Carbon-sulfur double bond ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hg[C(COF) = SF2 = O]2 is prepared by the reaction of FCO — CH = SF2 = O with HgF2. This compound represents the third known example of an alkylidenesulfur difluoride oxide. Its molecular structure is the same as that of the most abundant of the three isomers of FCO-CH = SF2 = O. This is assumed to be the result of weak intramolecular Hg… O contacts. With the exception of the fluorine atoms bound to sulfur, all atoms lie approximately in one plane.
    Zusätzliches Material: 1 Ill.
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  • 56
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 103-109 
    ISSN: 0009-2940
    Schlagwort(e): Asteranes ; Cage compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Asteranes, XXII1).  -  Synthesis of a Double Tetraasterane: Nonacyclo[10.8.0.02,11.04,9.04,19.06,17.07,16.09,14.014,19]eicosane1,4,5,8-Tetrahydronaphthalene-2,3-dicarboxylic anhydride (9) is dimerized by UV light in dioxane yielding four isomeric [2 + 2] adducts whose methyl ester derivatives are elucidated spectroscopically. The structures of the major products 14 and 16 have been confirmed by X-ray structure analysis. Degradation of the carboxylic groups of 14 afforded the title compound 5.
    Zusätzliches Material: 2 Ill.
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  • 57
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 157-162 
    ISSN: 0009-2940
    Schlagwort(e): Fluoro compounds, aromatic ; Nitrite exchange by fluoride ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of Aromatic Fluoro Compounds by Nucleophilic Exchange of Nitro Groups by FluorideThe synthesis of aromatic fluoro compounds from the respective nitro compounds by nucleophilic substitution of nitrite by fluoride is described. Reasonable yields in case of nonactivated nitro compounds are only obtained if the nitrite formed in the reaction is eliminated by acylation. 1-Fluoro-3-nitrobenzene (2) was obtained from 1,3-dinitrobenzene (1), and 1-fluoro-3,5-dinitrobenzene (9) as well as 1,3-difluoro-5-nitrobenzene (10) from 1,3,5-trinitrobenzene (8) in yields up to 92% by reaction of nitro compounds with potassium fluoride in sulfolane at 180 - 200°C in the presence of phthaloyl dichloride (6); 1,2-difluoro-4-nitrobenzene (12) was formed in 58% yield from 2,4-dinitro-1-fluorobenzene (11) in the presence of pyromellitoyl tetrachloride (13).
    Zusätzliches Material: 2 Tab.
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  • 58
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 13-16 
    ISSN: 0009-2940
    Schlagwort(e): Diphosphines, tetrakis(diisopropylamino) ; Phosphinous anhydrides ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Structure of Bis[bis(diisopropylamino)phosphino]chalcogenidesPhosphorodiamidous chalcogeno-anhydrides [(R2N)2P]2X (R = Me2CH; X = S, Se, Te) (2a-c) have been obtained by insertion of elemental sulfur, selenium, or tellurium into the P-P bond of the corresponding diphosphane (1). The structure of 2a and 2c has been confirmed by an X-ray diffraction.
    Zusätzliches Material: 3 Ill.
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  • 59
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 31-38 
    ISSN: 0009-2940
    Schlagwort(e): Fluorosulfonium salts, reaction with nucleophiles ; (Perfluoroakyl)(dimethylamino)sulfonium salts, preparation and structures of ; Methoxysulfinyl hexafluoroarsenate, alkylation with ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (Perfluoroalkyl)(dimethylamino)sulfonium HexafluoroarsenatesMeN = S(CF3)2 (5) is alkylated by Me3O⊕ AsF⊖6 to Me2N-S(CF3)⊕2 AsF⊖6 (4). From 5 and MeOSO⊕ AsF⊖6 (6) MeOS(O)-N(Me)S(CF3)⊕2 AsF⊖6 (7) is formed as a relatively stable primary product. Decomposition of 7 gives the expected 4 only in poor yield. Nucleophilic substitution of the sulfur-bonded fluorine in CF3SF⊕2 AsF⊖6 (8) by Me3SiNMe2 yields CF3S(NMe2)⊕2 AsF⊖6 (9). Similarly, (CF3)2CFSF⊕2 AsF⊖6 (10) reacts with dimethyl(trimethylsilyl)amine to give (CF3)2CFS(NMe2)⊕2 AsF⊖6 (11). The structures of 4 and 9 are elucidated by X-ray analyses, and the influence of the substituents on the bonding is discussed.
    Zusätzliches Material: 7 Ill.
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  • 60
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 63-67 
    ISSN: 0009-2940
    Schlagwort(e): Dinuclear gold complex ; Silyl complex ; Gold-gold interaction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Transition-Metal Silyl Complexes, 361).  -  On the Question of Gold-Gold Interactions in Ph2P[CH2]t(2)PPh2-Bridged Dinuclear Gold Silyl ComplexesDinuclear silyl gold complexes of the type dppm(AuSiR3)2 (1) or dppe(AuSiR3)2 (2) are prepared by the reaction of dppm-(AuCl)2 or dppe(AuCl)2 with two equivalents of LiSi(aryl)3 or LiSi(SiMe3)3 The complex dppe[AuSi(SiMe3)3]2 (2 c) exhibits crystallographic inversion symmetry, and therefore the distance between both gold atoms is a maximum. In dppm-(AuSiPh3)2 (1b) a gold-gold interaction between both gold atoms is observed [Au  -  Au 316.80(3) pm].
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 149-156 
    ISSN: 0009-2940
    Schlagwort(e): Cyclobutene, ring-opening ; Poly Diels-Alder reaction ; Molecules, double-stranded ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Cyclobutene Ring Opening: A Useful Reaction for the Synthesis of Double-Stranded MoleculesSyntheses and ring-opening reactions of the compounds endo-5a - e and 9a - c, all containing cyclobutene rings, are described. From these experiments it is concluded that compound 9a is a useful AB-type Diels-Alder monomer for the synthesis of well-defined double-stranded molecules. The stereochemistry of the adducts endo-4b and endo-5d is determined by X-ray structure analysis.
    Zusätzliches Material: 1 Ill.
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  • 62
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 175-184 
    ISSN: 0009-2940
    Schlagwort(e): α-Enones, regioselective 1,2-addition of dimethyl phosphite to ; Allylic rearrangement of dialkyl (1-hydroxy-2-alkenyl)phosphonates ; 1-Alkenylphosphonates, 3-acetyloxy- ; 1-Alkenylphosphonates, 3-hydroxy- ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of Dialkyl Phosphites with α-Enones, I. - Synthesis and Allylic Rearrangement of Dimethyl (1-Hydroxy-2-alkenyl)- and (1-Hydroxy-2-cycloalkenyl)phosphonatesVarious β,γ-unsaturated α-hydroxyphosphonates 3 are prepared in good yields by NaOCH3-catalyzed regioselective 1,2-addition of dimethyl phosphite to acyclic and cyclic α-enones at -35°C. On acid-catalyzed acetylation, the allylic α-hydroxyphosphonates 3 (R1, R2 + H) rearrange under thermodynamic control; yielding the new 3-acetyloxy-1-(cyclo)alkenyl derivatives 8, from which the transposed allylic alcohols 11 are readily obtained. Using shorter reaction times, acetylation of compounds 3 affords mixtures of 1- and 3-acetylated products, 10 and 8, respectively.
    Zusätzliches Material: 4 Tab.
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  • 63
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 207-212 
    ISSN: 0009-2940
    Schlagwort(e): 2,3,6-Trioxypentafulvenes ; Keto-enol tautomerism ; Push-pull system ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Syntheses of 2,3,6-trioxypentafulvenes with a free position at the ring are described, in which the protection of the C-3 hydroxy group as methoxy or acetoxy derivative has been required. The difference in the behavior of the title compounds in relation to the previously reported 1,4-disubstituted 2,3,6-trihydroxypentafulvenes 2a-e, which only exhibit enol forms, is discussed and attributed to the disappearance of the push-pull system formed by the C-3 enol group and the C-4 electron-withdrawing substituent.
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  • 64
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 233-235 
    ISSN: 0009-2940
    Schlagwort(e): Hexaoxacyclotriacontadodecaenes ; Macrocycles ; 2,2-Bis(2-furyl)propane ; 2,5-Bis[1-(2-furyl)-1-methylethyl]furan ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New O6 Macrocycles with 2,2-Bis(2-furyl)propane UnitsThe macrocycles 3a and 6 are prepared in 29 and 16% yield by cyclization of dilithiated 2,2-bis(2-furyl)propane (1) and 2,5-bis[1-(2-furyl) 1-methylethyl]furan (5), respectively, with ethyl N,N-dimethylcarbamate (2).
    Zusätzliches Material: 1 Tab.
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  • 65
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 237-240 
    ISSN: 0009-2940
    Schlagwort(e): Bicyclo[3.2.1]oct-6-yl cations ; Wagner-Meerwein rearrangements ; Alkyl-bridged ions ; Conformational effects ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Rearrangements of 1,4,4- and 2,2,5-Trimethylbicyclo[3.2.1]oct-6-yl Cations1,4,4-Trimethylbicyclo[3.2.1]oct-6-yl cations (18) are generated from the tosylhydrazone 7, by nitrous acid deamination of the amines 6 and 8, and by acetolysis of the brosylates 21 and 24. The product distributions are but slightly affected by the configuration (exo vs. endo) of the leaving groups. The predominant product, 1,4,4-trimethylbicyclo[3.2.1]octan-exo-6-ol (11) is formed without significant redistribution of a 6-2H label. The degenerate Wagner-Meerwein rearrangement of the parent bicyclo[3.2.1]oct-6-yl cation is virtually eliminated by the presence of two methyl groups at C-4. Enhanced conformational strain, raising the barrier to ring flipping, accounts for these observations. Minor products (12, 13) arise from a 7,6-hydride shift of 18, followed by Wagner-Meerwein rearrangement. When the 2,2,5-trimethylbicyclo[3.2.1]oct-6-yl cation (19) is generated directly from the tosylhydrazone 17, the tertiary alcohol 13 is obtained as the major product. The conformational barrier to Wagner-Meerwein rearrangement is compensated by the incipient stabilization of the tertiary carbocation 20.
    Zusätzliches Material: 1 Tab.
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  • 66
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 403-405 
    ISSN: 0009-2940
    Schlagwort(e): 1,2-Dihydropentalenes ; 1,5-Dihydropentalenes ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An efficient one-pot synthesis of 3-substituted 1-phenyl-1,2-dihydropentalenes from α,β-unsaturated ketones is described. These compounds can be rearranged to their 1,5-dihydro isomers using different methods such as acid catalysis and vacuum-flash thermolysis or by chromatography on alumina.
    Zusätzliches Material: 4 Tab.
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  • 67
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 417-421 
    ISSN: 0009-2940
    Schlagwort(e): Methylenephosphines ; Voltammetry, cyclic ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Electrochemical investigations on a selection of methylenephosphines 1 and related systems are reported. They are shown to possess an irreversible oxidation and reduction wave. An exception is diaminodiphosphene, which reversibly forms a radical anion. A relative ordering of frontier orbitals is possible, based on the redox properties of these systems.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 321-327 
    ISSN: 0009-2940
    Schlagwort(e): Trifluororthocarbonates of potassium, rubidium, cesium ; Phase transitions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Crystal Structures of Potassium, Rubidium, and Cesium Trifluororthocarbonate and a Remark Concerning the Barium Sulfate Type1)Crystals of potassium, rubidium, and cesium trifluororthocarbonate (9a, 9b, and 9c) have been grown by Ostwald ripening in CH3CN applying a COF2 pressure of 3 bar. According to X-ray single-crystal structure analysis, 9a, 9b, and 9c belong to the baryte-structure family with an pseudotetrahedral anion being dynamically disordered at room temperature. All of the title compounds undergo a phase transition into a monoclinic, completely ordered low-temperature form, which has been refined for 9c. The C - O bond seems to be shortened by polar interactions. The results obtained with 9a, 9b, and 9c at room temperature indicate that the type of disorder found in 9 might be generally present in baryte-type compounds.
    Zusätzliches Material: 2 Ill.
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  • 69
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 339-345 
    ISSN: 0009-2940
    Schlagwort(e): Photoadditions ; Caffeine derivatives ; Calculations, AM1 ; Diradicals ; Propellanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Selectivities in Photoadditions with Multifunctional Caffeine DerivativesElectronically excited stilbene (21*), 4,4′-dichlorostilbene (1*), and 4,4′-dimethoxystilbene (18*) are trapped by caffeine derivatives 2, 13, or 22 with variable results. While 1* and 2 react predominantly at the imino double bond (substitutive and fragmentating additions), 1* or 18* and 13 produce mostly propellanes by [2 + 2] photocycloaddition, which hydrolyze or may be hydrolyzed. 21* and the relatively electron-poor compound 22 produce mostly propellanes, which always show a preponderance of the syn-10, anti-11 stereoisomers. These selectivities as well as the competition with reactions at the imino double bonds are rationalized on the basis of diradical mechanisms with the aid of semiempirical AM1 calculations. Earlier results on closely related transformations are also discussed.
    Zusätzliches Material: 1 Ill.
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  • 70
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 377-381 
    ISSN: 0009-2940
    Schlagwort(e): Phosphorus compounds, organic ; Phosphorus heterocycles ; Arbuzov rearrangement ; Mechanism, SN2, SN1 ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Addition Reactions of Phosphorus Nucleophiles to BenzothieteTrialkyl phosphites 4 add to the o-quinoid form 2 of benzothiete (1) to yield the phosphonates 6. An intermolecular migration of an alkyl group from oxygen to sulfur is the most important feature of this transformation. The rearrangement - related to the Arbuzov reaction - can be avoided in a two-step process by the subsequent action of PCl3 and alcohol; thus the phosphonates 10 are generated. Analogous to 2 → 6, dimethyl phenylphosphinate (11) furnishes 13. In contrast, the cyclic esters 14a-d form 2:1 adducts, namely the 12- to 15-membered heterocyclic compounds 17a - d. An intramolecular rearrangement in a 1:1 adduct is only observed for the 1,3,2-dioxaphosphepine 14e, a benzylic system which allows an SN1 process generating the 1,6,2-oxathiaphosphecine 18e. A similar rearrangement at a tertiary carbon center is prevented by the competitive addition of water (1 + 14f → 20).
    Zusätzliches Material: 2 Tab.
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  • 71
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 391-396 
    ISSN: 0009-2940
    Schlagwort(e): Ozonolysis ; Cycloalkylidenecycloalkanes ; Dispiro-1,2,4-trioxolanes ; Thermolysis ; Photolysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dispiro-1,2,4-trioxolanes by Ozonolysis of Cycloalkylidenecycloalkanes on PolyethyleneOzonolyses of symmetrical (1b - d) and of unsymmetrical cycloalkylidenecycloalkanes (8a, b) afforded the dispiro-1,2,4-trioxolanes 4b - d and 9a, b, respectively. Their thermal decompositions gave mixtures of the cyclic ketones (3) and lactones (6). Photolyses afforded in addition to 3 and 6 the cyclic anhydrides 13, which are isomeric with the corresponding dispiro-1,2,4-trioxolanes.
    Zusätzliches Material: 1 Ill.
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  • 72
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 665-669 
    ISSN: 0009-2940
    Schlagwort(e): Semideltic acid ; Cyclopropenylium cations ; Pseudooxocarbon anions ; Semideltate anions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Pseudooxocarbon Anions of Semideltic AcidNovel pseudooxocarbon anions of semideltic acid (2) can easily be obtained by stepwise substitution of the dimethylamino groups of the cyclopropenium perchlorate 8. Treatment of 8 with cyanamide or malononitrile in the presence of triethylamine leads to the triafulvenes 9 and 13. Two cyanoimino groups are successfully introduced into the cyclopropenylium system by treating 9 with excess cyanamide/potassium ethoxide. Under the same conditions malononitrile reacts with 13 to yield the potassium salts 14 and 17. The thioamide 26 of semideltic acid is obtained by treating the triphenylphosphonium salt 24 with H2S/pyridine and subsequent hydrolysis of the intermediate 25. With the anions of cyanamide or malononitrile ring-opening reaction of the cyclopropenylium system of 24 occurs to yield the push-pull phosphonium salts 28 and 29.
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  • 73
    ISSN: 0009-2940
    Schlagwort(e): Ethylene-bridged metal complexes ; Ethanediyl complexes ; Manganese, Rhenium, Ruthenium, Osmium carbonyls ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hydrocarbon-Bridged Metal complexes, XVIII. - Heterometallic Ethylene-Bridged Complexes (OC)5ReCH2CH2Mn(CO)5, (OC)5ReCH2CH2Ru(CO)2Cp, (OC)5ReCH2CH2Os(CO)4CH2CH2Re(CO)5 and (OC)5ReCH2CH2CH2Os(CO)4Os(CO)4(CO)4Os(CO)4CH2CH2Re(CO)5Addition of [(OC)5Re(C2H4)]+ to the carbonylmetallates [Mn(CO)5]-, [RuCp(CO)2]-, [Os(CO)4]2-, [Os3(CO)12]2- affords the title complexes in a directed way. The dynamic behaviour of (OC)5ReCH2CH2Mn(CO)5 in solution is attributed to a dyotropic exchange of the pentacarbonylmetal groups on the CH2CH2 bridge.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 74
    ISSN: 0009-2940
    Schlagwort(e): [2.2.2]Paracyclophane ligand ; (η6)π Complexes ; Arsenic(III) complexes ; Antimony(III) complexes ; Bismuth(III) complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Arsenic(III), Antimony(III), and Bismuth(III) Trihalide Complexes of [2.2.2]Paracyclophane: From Weak van der Waals Coordination to Strongly Directional π Complexation with Single or Double External η6 Coordination[2.2.2]Paracyclophane forms the adducts C24H24·AsCl3 (1), C24H24·(SbCl3)2·1/2 C6H6 (2), and C24H24·(BiCl3)3·C6H6 (3). For solutions in polar solvents NMR spectra indicate extensive dissociation and/or fluxionality. In the crystals adduct 1 features a weak addition of the AsCl3 molecule to one open side of a paracyclophane molecule with long intermolecular contacts approaching C3v symmetry. - Crystalline 2 shows SbCl3 coordination to two of the benzene rings of the hydrocarbon in a quasi-centered η6 mode, while one of the benzene rings remains uncoordinated. Chlorine-bridging between antimony atoms leads to tetrameric units (SbCI3)4 in the lattice. - In the bismuth compound 3 each benzene ring of the hydrocarbon is engaged in centroid (η6)π complexation, with the BiCl3 units crosslinked by chlorine bridges. The average of the Bi-ring distances (3.08,2.98, and 2.99 Å) is shorter than for the Sb-ring distances in 2 (3.047 and 3.050 Å), indicating stronger bonding. The crystal benzene is not coordinating.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 75
    ISSN: 0009-2940
    Schlagwort(e): Metallacyclic organoaluminium, -gallium and -indium compounds ; MOVPE precursors ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Intramolecularly base-stabilized four-coordinated metallacyclic organoaluminium, -gallium, and -indium compounds C5H10-Al(CH2)3NMe2 (4), C4H8Ga(CH2)3NMe2 (5), C5H10Ga(CH2)3N-Me2 (6), C5H10GaCH2CH(Me)CH2NMe2 (7), C4H8Ga(CH2)4NMe2 (8), C5H10Ga(CH2)4NMe2 (9), EtAl[(CH2)3]2NMe (10), MeGa-[(CH2)3]2NMe (11), EtGa[(CH2)3]2NMe (12), MeIn[(CH2)3]2NMe (13), and (14) have been synthesized by the reaction of [3-(dimethylamino)propyl]aluminium dichloride (1), [3-(dimethylamino)propyl]gallium dichloride (2), [3-(dimethylamino)-2-methylpropyl]gallium dichloride (3), or [4-(dimethylamino)butyl)gallium dichloride with the respective bis-Grignard reagents or by the reaction of the organometal dichlorides RMCl2 with bis[3-(chloromagnesio)propyl]methylamine or with N,N′-bis[3-(chloromagnesio)propyl]-N,N′-dimethyl ethylenediamine. Aluminium or gallium trichloride reacts with tris[3-(chloromagnesio)propyl]amine to give Al[(CH2)3]3N (15) and Ga[(CH2)3]3N (16). The 1H-, 13C-NMR and mass spectra of the new compounds as well as the X-ray crystal structure of 16 are discussed. 4, 6, and 12 have been tested successfully as MOVPE precursors.
    Zusätzliches Material: 2 Ill.
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  • 76
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1143-1148 
    ISSN: 0009-2940
    Schlagwort(e): Ironcarbonyl complexes ; ortho-Metallation ; o-Semidine rearrangement ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Iron Carbonyl Induced o-Semidine Rearrangement of 1-Alkyl-2-aryldiazenesIrradiation of pentacarbonyl iron in the presence of Me3C - N=N - Ar (Ar=phenyl, p-tolyl, p-CH3OC6H4) produces in the first step ortho-metallated complexes of the type Me3C - N - N(H)RC6H3Fe(CO)3Fe(CO)3 (2a-c, R=H, Me, MeO). In a thermal consecutive step these intermediates undergo an o-semidine rearrangement to Me3C - NFe(CO)3 - Fe(CO)3N(H)RC6H3 (1a-c). The structure of 1a has been elucidated by X-ray structure analysis. Dynamic 13C-NMR spectra indicate restricted rotation of the Me3C group and hindered carbonyl scrambling for the latter and former complexes, respectively.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1161-1162 
    ISSN: 0009-2940
    Schlagwort(e): Semiconductor ; Photocatalysis ; Carbon dioxide ; Formate ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbon dioxide is catalytically reduced to formate in a suspension of zinc sulfide in water/2,5-dihydrofuran when irradiated (λ ≥ 290 nm). Turnover rates are in the range of 1.5 monolayers CO2/h. No reaction occurs at pH=12, and a very slow one at pH=3.2,5-Dihydrofuran functions as reducing agent which is oxidized to dehydro dimers. When it is substituted by 2-propanol, no CO2 reduction is observed. Semiconductor photocatalysis by a two-electron transfer from zinc sulfide to adsorbed hydrogen carbonate is assumed as the key step of CO2 fixation.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1181-1186 
    ISSN: 0009-2940
    Schlagwort(e): Stereoselective cyclizations ; Ethers, cyclic ; Dipolar cycloaddition ; Nitro olefins ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A convenient conversion of aldehydes via nitroolefins 2 into cyclic ethers 6 fused to an isoxazoline ring involves formation of unsaturated nitroalkyl ethers 4 and subsequent intramolecular cycloaddition of an in situ-formed nitrile oxide olefin. The cyclization proceeds with stereoselective formation of trans over cis isomers in the tetrahydrofuran series and opposite stereoselectivity in the tetrahydropyran and hexahydrooxepine series, depending on the substituent R in the original nitro compound, thus providing access to stereoselectively functionalized cyclic ethers.
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  • 79
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1223-1227 
    ISSN: 0009-2940
    Schlagwort(e): Cesium effect ; Clathrate ; Cyclophanes ; Acetylene, diphenyl ; Rigid-group principle ; Tolane ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Intra- and Extraannularly Functionalized [2.2.2]Phanes: Syntheses and PropertiesThe severely strained new cyclophanes 7b-f, consisting of bridged tolane subunits and bearing intraannular substituents R, were prepared mainly to study steric interactions of R with the “π cloud” of the triple bond. These compounds exist in a rigid twisted conformation, whereas the unsubstituted reference compound 7a and the extraannularly functionalized azo compound 9 show C2 symmetry. 9 forms a 1 : 1 clathrate with toluene.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 80
    ISSN: 0009-2940
    Schlagwort(e): Carbenoids ; Bromine-lithium exchange ; Asymmetric induction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bromine-lithium exchange in 1,1-dibromo-3-(trimethylsilyl-oxy)alkanes 4 and 6 affords the carbenoids 8 and 14, which have been added to ketones, aldehydes, arylboronates, and silylating agents. Diastereoselectivity in the generation and trapping of the carbenoids ranged between 70 - 90% for 8 and 〉90% for 14.
    Zusätzliches Material: 1 Tab.
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  • 81
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1271-1289 
    ISSN: 0009-2940
    Schlagwort(e): Dibenzo compounds, rigid face-to-face ; Photocycloadditions, [6 + 6] Benzo, Benzo ; Pagodanes, 4,9,14,19-tetrafunctionalized ; Functional Group Manipulations ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Various 4,9,14,19-tetrafunctionalized pagodanes are prepared by a de novo route commencing from appropriately substituted isodrin analogues (3, 4). With the 14,19-dimethoxypagodane-4,9-dicarboxylic esters 30/31, isolated after 16 one-pot operations (ca. 40 functional changes) in ca. 6.5% overall yield (ca. 84% per operation, ca. 93% per functional change), the scope for further functional group manipulations on the pagodane sphere is explored (e.g. diketone dicarboxylic ester 35, dimethoxy diketone 37, tetraketone 41). In two face-to-face dibenzo substrates (17, 49), clean photoequilibration with the corresponding syn-o,o'-dibenzo isomers (19, 50) (75: 25 and 80: 20, resp.) is observed upon direct excitation (λ=254 nm).
    Zusätzliches Material: 1 Ill.
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  • 82
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1311-1312 
    ISSN: 0009-2940
    Schlagwort(e): Anthracene adducts ; Sulfine, chloro(trichloromethyl)- ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of Chloro(trichloromethyl)sulfine, Cl3C(Cl)C=SOThe unstable trichlorothioacetyl chloride (2) could be trapped by a Diels-Alder reaction with anthracene to form the adduct 3, which in turn could be oxidized to the corresponding sulfine adduct 4. Finnaly, chloro(trichloromethyl)sulfine (5) was prepared in good yield by vacuum thermolysis (retro Diels-Alder reaction) of 4.
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  • 83
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1207-1213 
    ISSN: 0009-2940
    Schlagwort(e): Diazirines ; Phosphaalkynes ; Carbenes ; Phosphirenes ; [2 + 1] Cycloaddition ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Organophosphorus Compounds, 48. - 1-Halogen-1H-phosphirenes from Phosphaalkynes and ChlorocarbenesHalogen-substituted carbenes (7a - i), generated by thermolysis of diazirines (11a-i), add onto phosphaalkynes (8a-c) to form the title compounds (10a-1). Initially formed 2H-phosphirenes (9) could not be detected as their subsequent conversion to the 1H-isomers 10 by a 1,3-halogen shift is very fast. Hydrolysis of 10c,e,g-i and k yields vinylphosphonous acids (17a - e). 1-Chloro-1H-phosphirenes are transformed by nucleophilic substitution into fluoro (10a,c,e → 19a-c), bromo (10c,e → 20a,b), and iodo analogs (10c,e → 21a,b) with the help of silver tetrafluoroborate, trimethylsilyl bromide, and trimethylsilyl iodide, respectively. A crystal structure analysis of 10c is reported.
    Zusätzliches Material: 1 Ill.
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  • 84
    ISSN: 0009-2940
    Schlagwort(e): Carbene complexes of chromium and tungsten ; 1-Metalla-1,3,5-trienes ; 1-Metalla-1,3-dien-5-ynes ; Insertion of alkynes into M=C and C=C bonds ; [2 + 2] Cycloaddition reactions of carbene complexes and alkynes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Organic Syntheses via Transition Metal Complexes, 51. - 1-Metalla-1,3,5-trienes and 1-Metalla-1,3-dien-5-ynes of Chromium and Tungsten by Insertion of Alkynes into M=C and C=C Bonds of 1-Metalla-1,3-dienes and 1-Metalla-1-en-3-ynes, respectively1-Metalla-1,3,5-trienes LnM=C(NEt2)-C(Me)—C(OEt)-CH=CHPh (3,4) and LnM=C(OEt)- CH=C(NEt2) - C(Me)=CHPh [5, LnM=Cr(CO)5 (a), W(CO)5 (b)] are obtained for the first time from the corresponding 1-metalla-1,3-dienes LnM=C(OEt) - CH=CHPh (1a, b) under very mild conditions by the insertion of the electron-rich alkyne Et2N-C ≡ C - Me (2) into the M=C and the C=C bonds, respectively, of 1. The chelate complex (6b) and the cyclobutenyl carbene complex 7b are isolated as minor side products. 1-Metalla-1,3-dien-5-ynes LnM=C(NEt2) - C(Me)=C(OEt) - C ≡ CPh [9, 10, LnM=Cr(CO)5 (a), W(CO)5 (b)] are formed with high regio- and stereoselectivity on insertion of 2 into the M=C bonds of 1-metalla-1-en-3-ynes 8. X-ray data are given for the tungsten complex 3b.
    Zusätzliches Material: 1 Ill.
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  • 85
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1265-1270 
    ISSN: 0009-2940
    Schlagwort(e): Gas-phase pyrolysis ; Tandem mass spectrometry ; Carbonates ; Alkyl migration ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Gas-phase pyrolysis of dimethyl carbonate and its mono-, di-, and trithio analogs has been performed in the temperature range from 1253 to 1404 K applying the gas phase Curie-point pyrolysis technique. Real-time analyses have been carried out by means of mass-spectrometric techniques. The possible isomerizations of the ester functions have been studied by collisional activation mass spectrometry in combination with appropriate D, 18O, and 34S labeling. It is demonstrated that methyl group migrations can be induced pyrolytically in cases where oxygen-to-oxygen or oxygen-to-sulfur isomerizations are involved; in contrast, sulfur-to-oxygen as well as sulfur-to-sulfur isomerizations apparently do not take place.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991) 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1379-1395 
    ISSN: 0009-2940
    Schlagwort(e): Vinyl anions, chiral ; Umpolung ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The vinyllithium reagent 13 and its enantiomer are generated by a bromine/lithium exchange reaction starting from dibromoalkenes 11 and 12, both available from the corresponding enantiomer of alkyl lactate. When 13 is allowed to react with aldehydes or with acetophenone, a highly stereoselective addition to the Re face of the carbonyl compounds occurs to give predominantly the diastereomers 15. Alkenes 25a,c, accessible by another bromine/lithium exchange reaction of 15a,d and subsequent protonation, can be cleaved by ozonolysis followed by reduction to afford carbinols 27a, b in 〉 98% ee. The sequence corresponds to a stereoselective introduction of a methanol d1 synthon (⊖CH2OH) or, as shown by other examples, of acyl and formyl d1 synthons (⊖CRO and ⊕CHO) into prochiral carbonyl compounds. As a consequence, 13 and its enantiomer may be regarded as highly stereoselective reagents for "carbonyl umpolung". A series of further vinyllithium reagents, 38a-g and 54/55, is treated with benzaldehyde, but none of those displays comparable enantiofacial selectivity. The prerequisites to the highly stereoselective reactions of 13 and its enantiomer are briefly discussed.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1411-1414 
    ISSN: 0009-2940
    Schlagwort(e): Propane-1,2,3-trione, 1,3-diphenyl- ; Electron diffraction ; Gas-crystal structure comparison ; Conformation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The molecular structure of 1,3-diphenylpropane-1,2,3-trione (diphenyl triketone) has been determined by gas-phase electron diffraction at 130°C nozzle temperature. It has been found that the phenyl rings are nearly coplanar with the adjacent carbonyl groups, and the two Cph-C(O)-C(O)-C(O) dihedral angles are - 129.5 ± 0.8 and - 107.1 ± 0.8° (0° corresponds to the syn form). Bond distances (rg, Å) and bond angles (deg) with estimated total errors are C—H 1.105 ± 0.006, O = C 1.213 ± 0.003, 〈 Cph-Cph〉 1.404± 0.003, Cph-C(O) 1.478 ± 0.005, C(O)-C(O) 1.558 ± 0.004, Cph-C(O)-C(O) 120.0 ± 0.3, Cph—C(O)=O 120.8 ± 0.4, C(O)-C(O)-C(O) 117.3 ± 0.4, Cph-Cph(CO)-Cph 119.8 ± 0.6. Although there is a general agreement between the gas-phase and crystal molecular structures there are some notable differences. One of the benzene rings is slightly turned about the Cph-C(O) axis in the opposite direction in the gas molecule as compared to the crystal. This causes a marked shortening of the O… H intramolecular contact (to 2.18 Á) between the central oxygen and an ortho-hydrogen.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1431-1434 
    ISSN: 0009-2940
    Schlagwort(e): Proton transfer ; Fragmentation of rings ; Aryllithium ; Carbanions ; Imines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The title carbanions 1 are shown to lose nitrogen to afford ortho-carbiminophenyl anions 4 which can be protonated by inter- or intramolecular proton transfer or react inter- or intramolecularly with other types of electrophilic center.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1453-1460 
    ISSN: 0009-2940
    Schlagwort(e): Shock tube technique ; Oxygen scavanger ; Heat of formation ; Allyl resonance energy ; Radical disproportionation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Heat of Formation of the Allyl and Methallyl RadicalThe decomposition of 1,5-hexadiene (1), 2-methyl-1,5-hexadiene (7), and 2,5-dimethyl-1,5-hexadiene (5) into allyl- (2) and methallyl radicals (6) was studied by means of the shoke tube technique with and without oxygen as scavanger. From these data and from the temperature dependence of the equilibria 1 ⇌ 2 and 5 ⇌ 6, measured between 600 and 800°C, the heat of formation of the allyl (2) and methallyl radical (6) as well as the activation parameters for the recombination and disproportionation of these radicals have been deduced.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1461-1470 
    ISSN: 0009-2940
    Schlagwort(e): Allyl stabilisation energy ; Calculations, force field ; Rotational barrier, intrinsic ; Gas-phase kinetics ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Rotational Barriers of Vinyl-Substituted OlefinesFor the vinyl-substituted olefines 1 - 14 activation parameters for the geometrical isomerisation have been determined in the gas-phase. By comparison of these barriers with the corresponding ones of the isolated double bonds, each corrected by the contribution of the steric energy to the ground and transition state, a value of 13.5 ± 1.1 kcal mol-1 for the allyl stabilisation energy (ASE), defined as replacement of alkyl by vinyl, has been derived.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1471-1475 
    ISSN: 0009-2940
    Schlagwort(e): Polyacetylenes ; Cross conjugation ; Alkenes, tetraethynyl ; π-Systems, planar ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New Planar π-Systems, II1). - On the Preparation and Structure of Tetrakis(phenylethynyl)etheneThe preparation of tetrakis(phenylethynyl)ethene (1 b) has been repeated. Among various routes to this highly unsaturated cross-conjugated π-system, the dimerization of bromide 2 via the carbene 3 is the most simple one. Full spectroscopic data for 1 b are reported for the first time, as is its X-ray structural analysis at - 95°C.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1485-1487 
    ISSN: 0009-2940
    Schlagwort(e): Thioketenes ; Flash-vacuum pyrolysis ; Diels-Alder reaction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Flash-vacuum pyrolysis of 2,4-bis(dichloromethylene)-1,3-dithietane (1) at 820°C furnishes dichlorothioketene (2a) which may be trapped with cyclopentadiene (3) in a [4+2] cycloaddition. The constitution 4a of the product is confirmed by an X-ray structural analysis of the related cycloadduct 4b.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 94
    ISSN: 0009-2940
    Schlagwort(e): Spirosilicates, zwitterionic ; Bond cleavage, Si - C ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bis[2,3-naphthalenediolato(2 - )](pyrrolidiniomethyl)silicate Acetonitrile Solvate: Synthesis and Crystal and Molecular Structure of a Zwitterionic λ5-SpirosilicateThe zwitterionic spirocyclic bis[2,3-naphthalenediolato[2-)](pyrrolidiniomethyl)silicate (3) was synthesized and the crystal and molecular structure of its acetonitrile solvate 3 · CH3CN investigated. 3 was prepared by reaction of trimethoxy(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (9) with 2,3-dihydroxynaphthalene in acetonitrile. Reaction 9 → 3 involves a remarkable Si - C cleavage with formation of CH4. The pentacoordinate silicon atom of 3 · CH3CN is surrounded by 4 oxygen atoms and 1 carbon atom, the latter being in an equatorial position. The coordination polyhedron can be described as a distorted trigonal bipyramid (the structure is displaced by 20.5% from the trigonal bipyramid towards the square pyramid). The crystal lattice of 3·CH3CN contains centrosymmetric dimers of 3, built up by intermolecular N - H … O hydrogen bonds.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1517-1520 
    ISSN: 0009-2940
    Schlagwort(e): Diiminosuccinonitrile ; 2H-Imidazoles ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chemistry of Cyanogen: Reactions of Diiminosuccinonitrile (DISN) with Sulfenyl Chlorides, Chlorotrimethylsilane and Ring Closure to Trifluoromethyl-Substituted 2H-Imidazoles4,5-Dicyano-2-hydroxy-2-(trifluoromethyl)-2H-imidazole (1) is easily prepared by treating DISN with trifluoroacetic anhydride. In the presence of 4-(dimethylamino)pyridine, however, the O-acylated derivative 2 is formed in excellent yield, while the reaction of 1 with chlorotrimethylsilane affords the O-silylated product 6. A bi-1,2,5-thiadiazole of the formula S2(CN)4Cl2 (5) is the final reaction product, when DISN is treated with sulfur dichloride in the presence of “naked” chloride ions. On the other hand the non-heterocyclic N-sulfenyl derivative 4 has readily been obtained, when DISN is treated with F3CSCl instead. Finally a procedure is described to convert DISN into the corresponding N-silylated diimine 3.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1575-1577 
    ISSN: 0009-2940
    Schlagwort(e): Oxidative coupling of cyclopentadienide anion ; Dihydrofulvalene, molecular structure ; Migration of trimethylsilyl group ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of 1,2,4-tris(trimethylsilyl)cyclopentadienyllithium with ferric chloride in THF at -95°C leads to the formation of a thermally sensitive iron(III) complex which decomposes to the new dihydrofulvalene derivative 3,7-dihydro-1,3,3,5,7,7-hexakis(trimethylsilyl)fulvalene (1).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1677-1678 
    ISSN: 0009-2940
    Schlagwort(e): Cyclopentadienes, chiral ; Quinone adducts ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Diels-Alder adduct obtained by addition of quinone to the chiral cyclopentadiene 2 undergoes regioselective and stereoselective reduction after hydrogenation. The 4-hydroxy ketone 3 thus formed yields the title compound 1 in a thermal retro Diels-Alder process.
    Materialart: Digitale Medien
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  • 98
    ISSN: 0009-2940
    Schlagwort(e): P - P bond ; Alkyne insertion ; Diphosphamolybdacyclopentene ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Metal-Containing Heterocycles: Preparation, Properties, Reactions, LXXV1).  -  Synthesis of a Diphosphamolybdacyclopentene by Alkyne Insertion into the P - P Bond of a DiphosphamolybdacyclopropaneInsertion of the alkyne RC≡CR (R = CO2Me) into the P - P bond of the diphosphamolybdacyclopropane (5-C5H5)-(OC)2Mo-PPh2-PAr (2) [Ar = 2,4,6-(tBu)3C6H2] results in the formation of the thermally and kinetically stable diphosphamolybdacyclopentene (η5-C5H5)(OC)2Mo-PPh2-RC = CR-PAr (3), which is characterized on the basis of mass, IR, 31P{1H}-, 1H-, and 13C{1H}-NMR spectra.
    Materialart: Digitale Medien
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  • 99
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1733-1738 
    ISSN: 0009-2940
    Schlagwort(e): Phthalocyanine ; Ruthenium complexes ; Pyridines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Soluble Bisaxially Substituted (Phthalocyaninato)ruthenium ComplexesSeveral attempts to prepare (tBu4Pc)Ru only led to an impure product (tBu4Pc)RuLx. This reacts quantitatively with pyridine to form (tBu4Pc)Ru(py)2, easily purified by chromatography. In addition the preparation of (tBu4Pc)RuL2 with L = pyridine, 2-picoline (2-pic), 3-picoline (3-pic), 4-picoline (4-pic), 2,5-lutidine (2,5-lut), and 2,6-lutidine (2,6-lut), respectively, is described. All complexes are characterized by spectroscopic methods including 1H-NMR spectroscopy. Not even in the cases of (tBu4Pc)RuL2 with L = 2-pic and 2,5-lut, a careful removal of the ligands L by thermogravimetric methods (TG/DTA) leads to pure (tBu4Pc)Ru. For comparison, the bisadducts PcRuL2 with L = pyridine, picolines (2-pic, 3-pic, 4-pic), lutidines (2,3-lut, 2,5-lut, 2,6-lut), and chloropyridines (2-Clpy and 3-Clpy), respectively, are prepared by treatment of PcRu with an excess of the ligand. For the first time (phthalocyaninato)iron complexes PcFeL2 with sterically hindered axial ligands, e.g. PcFe(2-pic)2, are prepared and characterized by 57Fe Mößbauer spectroscopy.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1809-1817 
    ISSN: 0009-2940
    Schlagwort(e): Lithiation ; Mannich reaction ; Alkylation ; Grignard reaction ; Condensation ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phenols and naphthols are benzotriazolylmethylated by 1-(hydroxymethyl)-1H-benzotriazole (13) (a formaldehyde derivative) in the o- or (if both o-positions are occupied) in the p-position. The reaction can be extended to other aldehydes in the case of the naphthols. The methylene group in the o-(benzotriazolylmethyl)phenols can be lithiated (but only after trimethylsilyl protection of the hydroxy group) and then substituted by various electrophiles. The benzotriazole residues in both the primary products and in their substituted derivatives can be displaced by the alkyl anions of Grignard reagents or by hydride ions allowing the elaboration of many new types of substituted phenols.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
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