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Thermodynamics and kinetics of Novozym 435 catalyzed ring-opening polymerization of 1,4-dioxan-2-one

Author:
Dong, Feng-Xia, Xu, Chen, Tong, Xiao-Zuo, Wang, Xiu-Li, Song, Fei, Wang, Yu-Zhong
Source:
Journal of Molecular Catalysis. B, Enzymatic 2013 v.96 pp. 40-45
ISSN:
1381-1177
Subject:
activation energy, catalysts, catalytic activity, enthalpy, entropy, nuclear magnetic resonance spectroscopy, polymerization, tin
Abstract:
In this paper thermodynamics and kinetics of bulk ring-opening polymerization (ROP) of 1,4-dioxan-2-one (PDO) catalyzed by Novozym 435 were investigated. Results showed that the polymerization reached equilibrium after 12h at 60°C in the presence of 5wt% Novozym 435 (based on PDO). The calculated thermodynamic parameters, enthalpy and standard entropy of the polymerization, are −19kJmol−1 and −66JK−1mol−1, respectively. The kinetic plot of ln{([M]0−[M]e)/([M]t−[M]e)} vs time is linear, indicating that the polymerization is first order with respect to the monomer concentration. The calculated apparent activation energy (Eapp) is 45.3kJmol−1, which is lower than that using Sn(Oct)2 and La(OiPr)3 as catalysts. According to 1H NMR and GPC analysis, the ROP of PDO with Novozym 435 catalyzed follows monomer activated mechanism.
Agid:
855305