Poly(styrene-divinylbenzene) sulfonic acid resin (PDVB–PS-SO3H) is widely recognized as an excellent solid acid catalyst and cation exchange material, owing to its large specific surface area, tunable mesoporous structure, uniform strong acid active sites, and high thermal stability. In this study, a series of porous aromatic polymers (PDVB–PSs) were synthesized via a one-step hydrothermal copolymerization of styrene (ST) and divinylbenzene (DVB) with varying cross-linker contents, followed by sulfonation with concentrated sulfuric acid to obtain the corresponding sulfonic acid functionalized resins, PDVB–PS-SO3Hs. The dealkylation of 2,6-di-tert-butyl-p-cresol, with a molecular dynamic diameter of 1.19 nm, was employed as a probe reaction to investigate the influence of the resin structure and properties on the catalytic performance in Brønsted acid-catalyzed dealkylation. The specific surface area, pore volume, and average pore size of PDVB–PS-SO3Hs increased with the enhancement of DVB content. Under consistent sulfonation conditions, the sulfur content first increased and then decreased, reaching a maximum of 3.93 mmol/g for the 50 wt % DVB sample (50 wt % denotes the mass percentage of DVB in the resin). A linear correlation was observed between the sulfur content of the resins and the yield of dealkylation products. The 50 wt % PDVB–PS-SO3H exhibited the highest activity, selectivity, and stability, giving 97.7% yield of p-cresol. Moreover, it retained high performance with a p-cresol yield of 93.5% even after five consecutive cycles, which can be ascribed to its well-balanced mesoporous structure and optimal distribution of sulfonic acid groups. This work provides theoretical and methodological support for the design and synthesis of stable and efficient mesoporous resin-based solid acid catalysts applicable to high-temperature reactions.
Yang et al. (Thu,) studied this question.
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