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  • 1
    Electronic Resource
    Electronic Resource
    Mathematical model for the optimization of the reaction between 2,3-bis(m-tolyl)quinolizinium bromide and piperidine using a factorial design (1992)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 6 (1992), S. 1-10 
    Details
    ISSN: 0886-9383
    Keywords: Derivatization reaction ; Factorial design ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of nucleophiles have been successfully identified and quantified using the Kröhnke reaction with 2,3-diphenyl derivatives of quinolizinium salts. Optimization of the reaction conditions by means of a mathematical model involving analysis of the response surface has led to a better understanding of the factors exerting an influence on the above reaction.The parameters chosen were temperature, reaction time, base concentration, water concentration and nucleophile concentration. The reaction was developed in polar aprotic solvents (acetone, acetonitrile). To facilitate the nucleophilic attack, the presence of an organic base (triethylamine) was necessary, although concentrations in excess of 0·15M did not alter the development of the reaction. Since pharmaceutical solutions are often aqueous, the influence of water on the reaction was studied. Low water volumes have no significant influence on the opening of the quinolizinium ring by the nucleophilic reagent. However, when the water proportion exceeded that of the organic solvent, the fluorescence intensity was lower than expected. Development of the fluorescent reaction product was first detected 5 min after the reaction started. The fluorescence intensity reached its optimum value after 138 min.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180060102
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Dynamic mechanical and dielectric behavior of erucamide (13-cis-docosenamide), isotactic poly(propylene), and their blends (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1473-1482 
    Details
    ISSN: 0887-6266
    Keywords: poly(propylene) ; erucamide ; erucamide/poly(propylene) blends ; dynamic mechanical relaxations ; dielectric relaxations ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends of erucamide (13-cis-docosenamide) and isotactic poly(propylene) were analyzed by means of dynamic mechanical (at 3, 10, and 30 Hz) and dielectric (at 1, 6, and 20 kHz) techniques. The dependence of tan δ with temperature for each one of the blends has been fitted to Gaussian functions in order to deconvolute the overlapped relaxations. Three relaxations for i-PP, αi-PP, βi-PP, γi-PP, three for erucamide, αERU, βERU, and γERU, and five for their blends have been observed and assigned. They do not vary appreciably with composition, suggesting that the components are incompatible either as globules in the matrix or in the amorphous regions of the spherulites, and/or in their surroundings. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1473-1482, 1997
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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