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The synthesis of methylene diphenyl dimethylcarbamate(4,4’-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) as dual solvent-catalyst.The influences of the kind of anion in the ionic liquids,reaction conditions and the recycle of the ionic liquid on 4,4’-MDC synthesis reaction were investigated.In addition,the acid strength of ILs was determined by the Hammett method with UV-visible spectroscopy,and the acid strength-catalytic activity relationship was correlated.The activity estimation results showed thatHSO3-bmimCF3SO3 was the optimal dual solvent-catalyst.Under the suitable reaction conditions of 70°C,40 min,molar ratio of nMPC/nHCHO=10/1 and mass ratio of WILs/WMPC=4.5/1,the yield of 4,4’-MDC based on HCHO was 89.9% and the selectivity of 4,4’-MDC with respect to MPC was 74.9%.Besides,HSO3-bmimCF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.
The synthesis of methylene diphenyl dimethylcarbamate (4,4’-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) as dual solvent- influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4’-MDC synthesis reaction were investigated.In addition, the acid strength of ILs was determined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that HSO3-bmimCF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70 ° C, 40 min, molar ratio of nMPC / nHCHO = 10 / 1 and mass ratio of WILs / WMPC = 4.5 / 1, the yield of 4,4’-MDC based on HCHO was 89.9% and the selectivity of 4,4’-MDC with respect to MPC was 74.9% .esides, HSO3 -bmimCF3SO3 was reused four times after being purified and no significant loss in the catalytic a ctivity was observed.