Heterogeneous catalysis by new bead‐shaped polymer‐supported multisite phase transfer catalysts |
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Authors: | Eagambaram Murugan Prakash Gopinath |
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Institution: | Department of Physical Chemistry, School of Chemical Sciences, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India |
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Abstract: | Three different new insoluble bead‐shaped polymer‐supported multisite phase transfer catalysts containing two, four and six active sites have been prepared and characterized by FTIR, TGA, chloride ion] and SEM analyses. The presence of number of active sites in each catalyst and their corresponding catalytic ability were studied by determining pseudo‐first order rate constants for C‐alkylation of phenylacetonitrile (PAN) and four different substituted PAN as the substrate using a low concentration of NaOH (25% w/w) at 50 °C. The observed rate constants were compared with rate constants of same reactions catalyzed by single‐site catalyst under identical reaction conditions. From comparative study, the efficiency of catalysts were found to be in the order six‐site>four‐site>two‐site>single‐site thus confirming number of active sites in each catalyst. Further, the detailed kinetic profile of C‐alkylation of PAN has been investigated using the superior six‐site catalyst by varying stirring speed, substrate], catalyst], NaOH], and temperature. Based on the observed kinetic and activation parameters, an interfacial mechanism was proposed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 771–785, 2009 |
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Keywords: | FTIR interfacial mechanism phase transfer catalysis phenylacetonitrile recycling |
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