Zeolite Cs-X is an acknowledged representative basic catalyst useful for side-chain alkylation of toluene with methanol. In spite of numerous investigations, still there has been long lasting challenge for achieving high selectivity for side-chain alkylated products rather than ring alkylated products. In an effort to improve the yields of side-chain alkylated products, CO₂ was introduced during the toluene side-chain alkylation with methanol at 425 °C over Cs loaded faujasite catalyst. The CO₂ addition facilitated in removing the formed hydrogen by reverse water-gas shift reaction and enhanced the product yield. Interestingly, CO₂ addition helped in obtaining higher yields of side-chain alkylation products including styrene/ethylbenzene and α-methylstyrene/iso-propylbenzene. The CO₂ introduction resulted in less H₂ formation in the product stream during the reaction. Mesoporosity was also introduced to the zeolite X to improve the activity and product selectivity.

Cs-X沸石是公认的代表性碱性催化剂，可用于甲苯与甲醇的侧链烷基化。尽管进行了许多研究，但是对于实现对侧链烷基化产物而不是环烷基化产物的高选择性仍然存在着长期的挑战。为了提高侧链烷基化产物的收率，在负载Cs的八面沸石催化剂上于425℃用甲醇在甲苯侧链烷基化过程中引入了CO ₂。添加CO ₂有助于通过逆水煤气变换反应除去形成的氢，并提高了产物收率。有趣的是，CO ₂添加有助于获得更高收率的侧链烷基化产物，包括苯乙烯/乙苯和α-甲基苯乙烯/异丙基苯。引入CO ₂导致反应期间产物流中更少的H ₂形成。介孔率也被引入到沸石X中以改善活性和产物选择性。