Reaction kinetics of p-dichlorobenzene with sodium N-methyl-4-aminobutyrate

In order to investigate the effect of p-dichlorobenzene (DCB) and sodium N-methyl-4-aminobutyrate (SMAB) reaction on the polymerization of polyphenylene sulfide (PPS), reaction kinetics of DCB and SMAB under conditions similar to the preparation of PPS was studied. After the analysis of reaction network and simplifications of reaction processes, kinetic models of the formation of sodium N,N′-(1,4-phenylene)-N,N′-dimethyl-4,4′-diaminobutyrate and sodium N,N′-(1,3-phenylene)-N,N′-dimethyl-4,4′-diaminobutyrate (both denoted as d-SPMAB), sodium N-(3-chlorophenyl)-N-methyl-4-aminobutyrate (m-SCMAB), sodium N-(4-chlorophenyl)-N-methyl-4-aminobutyrate (p-SCMAB), and sodium p-chlorophenolate (p-SCP) were established. Following mass action law and steady state theory, the kinetic equations were derived and fitted with experiment data through linear regression. The fitting results show that the apparent activation energies for the formation of d-SPMAB, m-SCMAB, p-SCMAB, p-SCP are 168.8, 154.5, 120.3 and 131.6 kJ⋅mol⁻¹, respectively. A higher ratio of SMAB to DCB can accelerate the reaction but don′t change the reaction mechanism. Moreover, water is favorable to the hydrolysis of DCB, while the solvation of water hinders the substitution reaction between DCB and SMAB.