Zinc Carboxylate Functionalized Mesoporous SBA-15 Catalyst for Selective Synthesis of Methyl-4,4 '-di(phenylcarbamate)

Mesoporous SBA-15 functionalized with zinc carboxylate (ZC/SBA-15) was used as a heterogeneous catalyst for the selective synthesis of methyl-4,4'-di(phenylcarbamate) (MDC) from dimethyl carbonate (DMC) and 4,4'-methylenedianiline (MDA). ZC/SBA-15 was prepared in three steps: first, SBA-15 grafted with -CN group was synthesized via the conventional one-pot route; then the -CN group was converted into -COOH group in H2SO4 solution; lastly, Zn2+ ions were introduced into the material by a facile ion-exchange process. The catalyst ZC/SBA-15 exhibits high MDA conversion (near 100%) and MDC selectivity (about 86.5%) with good recyclability in the MDC synthesis; this may provide a new approach for the non-phosgene synthesis of isocyanates.