Synthesis of Methylene-Bis-(4-Phenylcarbamic Acid Esters) via the Condensation of Methyl Phenylcarbamate Catalysed by a Solid Sulfonated Polystyrene Acid Catalyst

Polystyrene-based solid acid catalysts were synthesized via suspension polymerization, followed by sulfonation with chlorosulfonic acid, the sulfonic acid groups are chemically bonded to the polystyrene matrix to produce solid sulfonated polystyrene acid.Preparation of a solid sulfonated polystyrene acid catalyst for the catalytic condensation of methyl phenylcarbamate (MPC) and formaldehyde (HCHO) to produce methylene-bis-(4-phenylcarbamic acid esters) (MDC). The systematic investigation was conducted on the preparation methods of polystyrene-based solid acid catalysts to elucidate their acidic properties and catalytic performance. Using a combination of characterization techniques, including FT-IR、XPS、SEM、TG、EA, the study revealed that the catalyst prepared with chlorosulfonic acid as the sulfonating agent exhibited high catalytic efficiency in the synthesis of MDC. Specifically, when MPC reacted with formaldehyde at 80 °C for 3 h, it achieved an MDC yield of 45.6% and MDC selectivity of 79.8%.