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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 34 (1995), S. 1536-1538 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 5 (1998), S. 95-103 
    ISSN: 1572-8935
    Keywords: Copolymerization ; Phosphazene ; Thermal analysis ; Reaction kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The radical copolymerizations of I (2-allylphenoxyorganocyclotriphosphazene) with chloride, phenoxy, 2,2,2-trifluoroethoxy side group reacting with II (styrene, methyl methacrylate and vinylbenzyl chloride) using AIBN, n-BuLi and ultraviolet as initiator were investigated. The type of the copolymerization, reaction time, temperature were evaluated to obtain the optimum reaction condition. The incorporation of organophosphazene units into an organic polymer backbone decreased the glass transition temperature and increased the thermal stability of the copolymers. The weight conversion and the molecular weight had a maximum value at reaction temperature of around 70 °C. The order for both weight conversion of the copolymerization and the thermal stability of phosphazene polymer with the co-monomer was VBC 〉 STY 〉 MMA, and with the side group Cl-〉 C6H5O-〉 CF3CH2O-. The phosphazene copolymer is of conductivity and crystallization.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 20 (1997), S. 17-22 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mass transfer with chemical reaction by liquid/liquid phase tranfer catalysis (LLPTC) for an isothermal batch reactor was analyzed. The results for the phase transfer catalyzed reaction system can be generally described by a pseudo first-order hypothesis, whereas the reaction system can be controlled by simultaneous mass transfer of the catalysts between two liquid phases and chemical reaction in the organic phase. The mass transfer limitation is mainly from the mass transfer step of QX from the organic phase to the aqueous phase. The concept of catalyst-effectiveness vs. physically meaningful parameters in a liquid/liquid phase transfer catalyzed reaction is introduced. The catalyst effectiveness is increased as the mass transfer factors increase, the ratio of reaction rate coefficients of aqueous forward reaction to organic increases, and the equilibrium constant in the aqueous solution increases.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 64 (1995), S. 325-330 
    ISSN: 0268-2575
    Keywords: reaction kinetics ; phase-transfer catalysis ; synthesis ; acetals ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reactions of phenol with dichloromethane using quaternary ammonium salts as a liquid-liquid phase-transfer catalyst in an organic solvent/alkaline solution were investigated. The technique of phase-transfer catalysis had a dramatic accelerating effect on the reaction and increased the yield of diphenoxymethane by more than 95%. The effects of catalysts, temperature, and basic concentration on reaction rate were studied in order to find the optimum operating conditions for this reaction. Experimental results indicated that a potassium hydroxide was preferred over sodium hydroxide in order to enhance the reactivity of the reaction. The reaction rate constant and the distribution coefficient of the intermediate product were obtained. During the reaction, the concentration of the intermediate product was also measured in order to study its behavior in the liquid-liquid system.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 67 (1996), S. 381-387 
    ISSN: 0268-2575
    Keywords: reaction kinetics ; phase-transfer catalysis ; organometallics ; carbonylation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The carbonylation of α-Bromo-p-xylene (BrCH2C6H4CH3, BX) with iron pentacarbonyl (Fe(CO)5) by phase-transfer catalysis was studied in an organic solvent/alkaline solution. The reaction mechanism was corrected and clarified. The concentrations of base, reactant and catalyst, volume ratio, the kind of catalysts, organometals and solvents were evaluated to find the optimum condition in this reaction. The technique of phase-transfer catalysis has a dramatic accelerating effect on the reaction. In examining eight kinds of phase-transfer catalysts, tetra-n-butylammonium cation and tetra-n-butylphosphonium cation were found to be the best for increasing the yield of bis(p-methylbenzyl) ketone ((p-CH3C6H4CH2)2CO, BMBK). The amount of phase-transfer catalyst, the concentration of NaOH, the molar ratio of BX to Fe(CO)5 and the volume ratio of aqueous to organic phase affected the product selectivity.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 1309-1318 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The substitution reaction of hexachlorocyclotriphosphazene, N3P3Cl6, with phenol was performed to synthesize the partially substituted (phenoxy) chlorocyclotriphosphazenes, N3P3Cl6 - i(OC6H5)i, i = 1 - 6 by phase-transfer catalysis (PTC) in an organic phase/alkaline solution. The steric hindrance effect plays a crucial role in this reaction. The reaction system was controlled by both chemical kinetics and mass-transfer effects. The mass transfer of the catalyst between two phases was investigated by a pseudosteady-state liquid-liquid PTC (LLPTC) model. Also, the intrinsic reaction-rate constants of the series substitution and the overall mass-transfer coefficient of the catalyst from the organic phase to the aqueous phase were determined by a combined model. In addition, the corresponding energies, enthalpies, and entropies of activation of the series substitution were also estimated.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1351-1358 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The monomer 2-allylphenoxyorganocyclotriphosphazene I with phenoxy (or 2,2,2-trifluoroethoxy) side group was synthesized on reacting hexachlorocyclotriphosphazene with phenol (or 2,2,2-trifluoroethanol) and 2-allylphenol with phase-transfer catalysis in a dichloromethane/alkaline solution. The synthesis had a large yield (〉80%) and narrow product distribution and proceeded under mild condition. The radical copolymerization of I with II (styrene, methyl methacrylate, and vinylbenzyl chloride) using azobis(isobutyrylnitrile) (AIBN) as an initiator was investigated. Reactivity ratios and Alfrey-Price parameters for copolymers were obtained. Organophosphazene monomer I was less reactive than II. The thermal stability of the copolymer with phenoxy side group was greater than that with 2,2,2-trifluoroethoxy side group. The incorporation of organophosphazene units into an organic polymer backbone decreased the glass transition temperature and increased the thermal stability of the copolymers. Tensile measurement showed that Young's modulus tended to decrease and the polymer became softer and ductile when the incorporated amount of I increases. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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