MCM‐49 Zeolite: Enhanced Synthesis and Catalytic Performance Through Seed Crystal Addition–A Case Study in 1,2,4‐Trimethylbenzene Isomerization

Abstract MCM‐49 zeolites were synthesized under static conditions through seed‐assisted, two‐step variable‐temperature method, with cyclohexylamine (CHA) employed as the organic structure‐directing agent (OSDA). The effects of seed crystals on zeolite formation were systematically investigated through multiple characterization techniques. The results demonstrated that seed introduction effectively facilitated MCM‐49 synthesis, with crystallinity progressively enhancing as seed dosage increased. When the seed addition was 20%, the crystallinity reached maximum and the formation of impurity phase was effectively restrained. The catalytic performances of the synthesized samples were evaluated through isomerization of 1,2,4‐trimethylbenzene. The reaction results demonstrated that the sample with a 20% seed crystal addition exhibited the best catalytic performance: the mass conversion rate of 1,2,4‐trimethylbenzene, mass yield of 1,3,5‐trimethylbenzene, and selectivity for 1,3,5‐trimethylbenzene reaching 41.80%, 25.21%, and 60.30%, respectively.