Ammonia pools effect in Cs modified X zeolites for side-chain alkylation of toluene with methanol

The strategy of in situ ammonia production from ammonia pools can modulate the Lewis acid-base pairs and distribution of alkali metal states in FAU zeolite, thereby constructing a superior catalyst for toluene side-chain alkylation. [Display omitted] •The ammonia pools effect (APE) modulates the Lewis acid-base pairs and Cs states in Cs-X zeolite.•The strategy of APE significantly promotes the performances for toluene side-chain alkylation.•the APE reduction contributes to the formation of the active intermediates of m-HCOO*. Side-chain alkylation of toluene with methanol is a potential route for producing styrene. However, there are several challenges that prevent its industrialization, comprising the decomposition of methanol to CO and H2, and unavoidable by-products of ethylbenzene. Herein, we disclose that X zeolite after ion exchange of ammonium have an interesting and unexpected feature. It can modulate the Lewis acid-base pairs, via in situ ammonia production from ammonia pools, meanwhile, lead to more Cs+ species left in the zeolite, thereby constructing a superior catalyst for toluene side-chain alkylation. Especially for CsX-ex-AP catalyst, the ammonia pools effect (APE) in CsX-ex can achieve both higher toluene conversion and styrene selectivity. Furthermore, the methanol utilization efficiency increases significantly after APE reduction, indicating the selective catalysis for non-oxidative methanol dehydrogenation by in situ NH3 production from ammonia pools. In addition, the APE reduction contributes to the formation of the active intermediates of m-HCOO* species, which is another reason responsible for the superior performance.