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  • 1
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of azobenzene formation (1975)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 97 (1975), S. 368-373 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00835a025
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Solvent effects on aromatic nucleophilic substitution reactions. Part 7. Determination of the empirical polarity parameter ET(30) for dipolar hydrogen bond acceptor-co-solvent (chloroform or dichloromethane) mixtures. Kinetics of the reactions of halonitrobenzenes with aliphatic amines (1997)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 10 (1997), S. 849-860 
    Details
    ISSN: 0894-3230
    Keywords: solvent effects ; aromatic nucleophilic substitutions ; empirical polarity parameter ; halonitrobenzenes ; aliphaticamines ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Empirical solvent polarity parameters ET(30) were determined by UV/VIS spectroscopy, using Dimroth-Reichardt's betaine dye, as a function of composition, for several binary solvent mixtures [i.e. polar hydrogen bond acceptor (PHBA) solvents+chloroform or dichloromethane]. Each solvent system was analyzed according to its deviations from additivity due to preferential solvation of the chemical probe and also from complicated intermolecular interactions of the mixed solvents. The ET(30) parameter of many of these mixtures has presented synergism. The synergetic effects were more significant for those binary solvent systems in which chloroform is the co-solvent. These results were related to the solvent effects on some aromatic nucleophilic substitution reactions. The kinetics of the reactions between 1-halo-2,4-dinitrobenzenes and primary or secondary aliphatic amines were studied in three solvent systems (PHBA+chloroform) where the synergism for the ET(30) polarity parameter is the rule. In all the aminodehalogenation reactions discussed the formation of the intermediate is the rate-determining step. The kinetic data show a tendency to decrease with decrease in the overall solvation capability of the binary mixture. In general, the reaction rates presented a gradual decrease in the PHBA solvent-rich zone and a large decrease at high co-solvent concentrations. The ET(30) values corresponding to binary dipolar hydrogen bond acceptor-hydrogen bond donor mixtures may be not generally valid for interpreting solvation effects on the reactions under consideration. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Solvent effects on aromatic nucleophilic substitutions. Part 6. Kinetics of the reaction of 1-chloro-2, 4-dinitrobenzene with piperidine in binary solvent mixturesPresented in part at the XX Congreso Argentino de Química, Córdoba, Argentina 1994. (1996)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 9 (1996), S. 459-470 
    Details
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the reaction between 1-chloro-2,4-dinitrobenzene and piperidine was studied in several completely non-aqueous binary solvent mixtures where the preferential solvation is the rule at 15, 25 and 40°C. The reaction was chosen as the simplest example of aromatic nucleophilic substitutions (ANS). For (aprotic solvent + aprotic co-solvent) binary systems the co-solvent was toluene, and the rest of the solvents used were selected with different structural characteristics and an extensive range of polarity. In this kind of mixture a property of mixed binary solvents would be defined by means of ET(30) values and the solvent effects on this simple model of ANS reactions are similar to those of aprotic pure solvents, especially if hydrogen-bond donor solvent mixtures are excluded from the analysis. For (aprotic solvent + protic co-solvent) binary systems the co-solvent used was methanol. The presence of a protic solvent in the mixture strongly determines the solvent effects on the reaction. In this type of binary mixture, the chemical probe under consideration may not be generally valid to interpret solvation effects. Additionally, empirical solvent polarity parameters ET(30) were determined UV-VIS spectrophotometrically for some pure aprotic solvents and, as a function of the composition, for (dimethylformamide + toluene), (toluene + methanol) and (1,1,1-trichloroethane + methanol) at 15 and 40°C, with the purpose of extending the studies on the empirical polarity indices in binary solvent mixtures to the thermo-solvatochromic area.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Determination of the empirical polarity parameter ET(30) for binary solvent mixturesSee Ref. 1. (1995)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 8 (1995), S. 617-625 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Empirical solvent polarity parameters ET(30) were determined by UV-visible spectrophotometry using Dimroth- Reichardt's betaine dye, as a function of composition, for (aprotic + aprotic) and (aprotic + protic) binary solvent mixtures. For (aprotic + aprotic) solvent systems the cosolvent was toluene, and the other solvents used were selected with different structural characteristics and an extensive range of polarity: chloroform, 1,4-dioxane, ethyl acetate, tetrahydrofuran, acetone, nitromethane and N,N-dimethylformamide. For (aprotic + protic) solvent systems, the protic cosolvent used was methanol, and the aprotic solvents selected were toluene, chloroform, 1,1,1-trichloroethane, tetrahydrofuran, acetone, N,N-dimethylformamide, and dimethyl sulphoxide. Each system was analysed according to its deviations from additivity due to selective solvation of the betaine. A preliminary application of these empirical solvent polarity parameters was related to the solvent effects in a simple example of a nucleophilic aromatic substitution reaction.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610080908
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    Paper (German National Licenses)
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