| abstract |
The present invention relates to the technical field of catalysts, and in particular, to a combined catalyst and a preparation method therefor, and a method for preparing dimethylbenzene by carbon dioxide hydrogenation coupled toluene alkylation. The combined catalyst provided in the present invention comprises a metal oxide and a molecular sieve. In the present invention, the metal oxide is mainly used for reducing carbon dioxide into methanol, the molecular sieve is mainly used for reacting toluene and methanol to produce dimethylbenzene. Dimethylbenzene is prepared by using the catalyst provided in the present invention, so that carbon dioxide and hydrogen can be used as raw materials to replace methanol; compared with traditional methods for toluene alkylation with methanol, methanol-to-olefin side reaction caused by an inappropriate feed ratio of methanol/toluene can be avoided, and production efficiency of dimethylbenzene is improved; and moreover, isomerization reaction of dimethylbenzene can be suppressed to improve the selectivity of dimethylbenzene in a product. |