Preparation of a novel poly(vinylsulfonic acid)-grafted solid phase acid catalyst and its use in esterification reactions

摘要

A high-density sulfonic acid polymer, grafted onto a carrier surface, was synthesized from the acid form of vinylsulfonic acid monomer, and its catalytic activity as a new class of heterogeneous acid catalyst demonstrated in esterification reactions.rnPoly(vinylsulfonic acid) (PVS) has a high acid density (ion-exchange capacity; IEC = 9.2 meq g~(-1)) and is the solid-state analogue of sulfuric acid. PVS is expected to have various applications, such as strong cationic exchange, for water retention, and as an acid catalyst. Hitherto, the preparation of PVS in very high acid-purity and metal-free state from vinylsulfonic acid (VSA) has presented constraints due to difficulties in the purification of the acid form of the VSA monomer and in the cation exchange of the sodium form of PVS. We have recently succeeded in polymerizing vinylsulfonic acid (VSA) of very high acid-purity (>98.1 wt%) and metal-free (<20 ppb) in water to yield PVS (Scheme la).