N-vinylcarbazole polymerization by 13X molecular sieve exchanged with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) |
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| Institution: | 1. Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India;2. Materials Science Centre, Indian Institute of Technology, Kharagpur 721302, India;1. Department Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry and Materials Science, International Joint Research Center and Lab for Catalytic Technology, Heilongjiang University, Harbin 150080, Heilongjiang, China;2. School of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, Heilongjiang, China;3. State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China |
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| Abstract: | The polymerization of N-vinylcarbazole by 13X molecular sieves modified by five different transition metal ions, viz. Mn(II), Co(II), Ni(II), Cu(II) and Zn(II), has been studied under various conditions. The order of reactivity follows the trend: Mn(II) ≈ Cu(II) > Co(II) > Zn(II) > Ni(II) at pH ∼ 3.55 and an exchange level of 30% of the metal ion. The polymerizations are believed to occur by a dual-ion-initiation mechanism in which both metal ions and proton centres participate. The overall energy of activation (Ea) for each system decreases with decreasing pH of the exchanging salt solution. Average activation energy on proton centre (EH) and that on metal ion centre (Ea) have been evaluated for each system. Ea, EH and Ec have been shown to correlate with one another. The molecular weights and their distributions are affected by the nature of the metal ion and also by the protonic centres. The possibility of a correlation of the catalytic activity of the modified 13X with ionic radius, electronegativity and normal co-ordination number has been examined. |
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