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  • 1960-1964  (12)
  • 1950-1954
  • 1935-1939
  • 1920-1924
  • 1880-1889
  • 1963  (7)
  • 1962  (5)
  • 1886
  • 1883
  • Alkenes  (4)
  • Phosphorus  (4)
  • Reaction mechanisms  (4)
Material
Years
  • 1960-1964  (12)
  • 1950-1954
  • 1935-1939
  • 1920-1924
  • 1880-1889
Year
  • 1963  (7)
  • 1962  (5)
  • 1886
  • 1883
  • 1964  (4)
  • 1
    ISSN: 0570-0833
    Keywords: Kinetics ; Dipolar cycloaddition ; Cycloaddition ; Heterocycles ; Reaction mechanisms ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Criteria for the mechanism of 1,3-dipolar cycloadditions which lead to 5-membered rings are provided by the stereoselectivity observed with cis-trans isomeric dipolarophiles, by the effect of solvent and substituents on the rate constants, by the activation parameters, and by orientation phenomena. A concerted addition, which can also be described in terms of molecular orbitals and in which the two new σ-bonds are formed simultaneously, although not necessarily at equal rates, offers the best explanation of the experimental facts.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0570-0833
    Keywords: Koch carboxylic acid synthesis ; Carboxylic acids ; Alkenes ; Isomerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When straight-chain mono-olefins, from pentene to decene, are subjected to the Koch carboxylic acid synthesis by the addition of CO and H2O or CH3OH in the presence of strongly acidic catalysts, not only the expected secondary acids, but also mixtures of a specific type of tertiary acids or their methyl esters are formed. When the catalysts contain boron trifluoride, the secondary acids are formed in ratios of isomers which are, within the scope of this investigation, independent of the experimental conditions and which agree well with the values calculated from the isomer equilibria of the corresponding n-olefins. Using concentrated sulfuric acid as catalyst, a larger proportion of tertiary acids is obtained than with BF3-catalysis, and amongst the secondary acids, those isomers predominate in which the COOH group is situated near the centre of the molecule.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 723-735 
    ISSN: 0570-0833
    Keywords: Phenol oxidation ; C-C coupling ; Reaction mechanisms ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of well-known phenol oxidation reactions for the preparation of compounds arising from C—C and C—O coupling has recently received increased attention. A selection from the large number of products obtainable by oxidation of mono- and polyhydric phenols and a discussion of the reaction mechanisms indicate the scope of this method. The formation of hydroxyphenylquinones and orceine dyes from resorcinol derivatives is explained. The synthesis of natural products by way of phenol oxidations is briefly discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 295-308 
    ISSN: 0570-0833
    Keywords: Emulsion polymerization ; Polymerization ; Polymerization ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionizing radiation induces the polymerization of some vinyl monomers in aqueous emulsion with high radiation yields. With identical emulsion compositions, the kinetics of this reaction and the kinetics of emulsion polymerization induced by water-soluble initiators are very similar. The rate of reaction in emulsion polymerization is about one hundred times greater than in bulk polymerization. The initiation of emulsion polymerization by means of ionizing radiation permits uniform “illumination” of the reacting volume, as well as almost any desired variation in the frequency of initiation during the reaction. The sharp decrease in the overall rate of reaction when initiation is interrupted during emulsion polymerization of styrene induced by γ-rays contradicts the earlier concept of sharply separated reaction zones.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 523-530 
    ISSN: 0570-0833
    Keywords: Semimetals ; Metallic structure ; Nonmetallic structure ; Antimony ; Arsenic ; Bismuth ; Phosphorus ; Tellurium ; Tin ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements on semimetals have been continued. Studies of the dependence on temperature of various properties have provided details regarding the transition from the nonmetallic to the more metallic structure. A second-order transition has been found for tin at 170 °C, in which the c-axis remains unchanged, while the a-axis undergoes a small, discontinuous elongation.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 646-654 
    ISSN: 0570-0833
    Keywords: Polyphosphanes ; Phosphanes ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: While silicon and sulfur, which are situated to the left and to the right of phosphorus in the periodic table, from numerous chain and cyclic Si-Si and S-S-compounds with varying numbers of members, until recently the polyphosphance chemistry has been limited to the two-membered compounds diphosphane P2H4 and its derivatives. A number of results obtained in studies on polyphosphanes carried out in recent years will therefore be discussed, which, together with some more recent work by other authors, have led to an expansion of our knowledge of the prepration and properties of straight and branched-chain as well as of cyclic and polycylic -P-P-systems.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    ISSN: 0570-0833
    Keywords: Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low temperatures, ethylene and α-olefins (Δ1-olefins or 1-alkenes) are rapidly converted into oligomrs by the two-component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium-carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium-carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium-carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium-carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin-cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance of hydride transfers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 80-88 
    ISSN: 0570-0833
    Keywords: Oxidation ; Palladium ; Catalysis ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of olefins to carbonyl compounds with palladium compounds, especially the oxidation of ethylene to acetaldehyde, is at present carried out on a technical scale. The reaction takes place via a palladium-olefin complex, the formation of which is inhibited by halide ions. Hydrolysis to the carbonyl compound is inhibited by hydrogen ions. The knowledge gained by studying the reaction of olefins with pure solutions of palladium salts allows important conclusions to be drawn concerning the action of technical catalyst solutions containing copper and palladium chloride.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0570-0833
    Keywords: Elimination ; Reaction mechanisms ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In bimolecular β-elimination (E 2 mechanism), several bonds are ruptured or formed in one concerted reaction step. However, the various aspects of bond-making or -breaking need not be completely synchronous. In the E 2 transition state for elimination HX, rupture of the C—X bond may be more advanced than that of the C—H linkage, or vice versa. Factors influencing the relative extents of rupture of these two bonds at the transition state are discussed, and the consequences of non-synchroneity in one sense or the other are developed from theory and illustrated from experiment. This treatment provides an understanding of the Hofmann-vs.-Saytzeff orientation problem.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 617-621 
    ISSN: 0570-0833
    Keywords: Isocyanates ; Phosphorus ; Silicon ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several aminoaryl esters of phosphoric and thiophosphoric acids were prepared by the reaction of phosphorus pentahalides with nitrophenols, followed by catalytic hydrogenation, or by treating aminophenols with phosphorus trihalides and oxidation to pentavalent phosphorus. These amino esters were then converted into isocyanato esters by the action of phosgene. Isocyanates of phosphonates have been synthetized on the same principle, as well as via the Arbusov reaction of halogen-substituted isocyanates with trialkyl phosphites. The reaction of silicon halides or alkylhalogenosilanes with aminophenols yielded aminoaryl esters of silicic acid or its derivatives, which could also be treated with phosgene to convert them into isocyanato esters.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 652-656 
    ISSN: 0570-0833
    Keywords: β-Chloroethanephosphonic dichloride ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylene, phosphorus trichloride, and oxygen react together to give β-chloroethylphosphonic dichloride in good yields. Being a bifunctional acid chloride, this compound undergoes polycondensation reactions with other, at least bifunctional, compounds affording polyesters, polyamides, epoxy resins, etc. β-Chloroethylphosphonic dichloride also may be converted into vinylphosphonic dichloride, thus serving as a starting material for the preparation of vinylphosphonic acid and its derivatives. These undergo both homopolymerization and copolymerization with compounds containing olefinic double bonds. The products are used in the field of synthetic resins, for dressing textiles, and as protective surface coatings.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 382-393 
    ISSN: 0570-0833
    Keywords: Electrophilic reactions ; Reaction mechanisms ; Substitution ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results obtained in recent years from investigations into the mechanisms of electrophilic substitution reaction at sp3-hybridized carbon atoms are reviewed.
    Type of Medium: Electronic Resource
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