苯与合成气的烷基化反应旨在利用非石油资源生产甲苯、二甲苯等烷基苯，本工作采用甲醇蒸气预积炭制备一系列的ZSM-5分子筛，并与ZnCrO_x复合形成双功能催化剂，探索对苯和合成气烷基化制烷基苯的影响。通过对预积炭时间的考察，发现适当的预积炭能显著提高ZSM-5分子筛的催化性能。在450 ℃、4.0 MPa的反应条件下，预积炭改性24 h的催化剂苯转化率达到20.18%。对预积炭改性的ZSM-5分子筛和反应后的复合催化剂进行分析，表明预积炭改变了分子筛的酸性。预积炭覆盖了ZSM-5分子筛上的一些B酸位点，降低了B/L酸比，从而提高苯的转化率。最后，通过烃池机理对苯与合成气烷基化反应的失活机理进行合理推测。

Toluene, xylene and other alkylbenzenes are important basic chemical raw materials, which mainly come from the petrochemical industry. With the increasing foreign dependence of petroleum resources in China, the development of coal-to-aromatics technology can not only alleviate the problem of shortage of petroleum resources in China, but also promote the transformation and upgrading of consumption in the traditional coal chemical industry and promote the clean and efficient use of coal. In this paper, methanol-modified ZSM-5 molecular sieves were used and mechanically milled with ZnCrO_x in a mass ratio of 3∶1 as a composite catalyst, so as to investigate the catalytic effect of pre-preg carbon modified ZSM-5 molecular sieves. Under the reaction conditions of 450 ℃ and 4.0 MPa, the catalytic performance of the catalyst modified with pre-built carbon for 24 h was the best, in which the conversion of benzene reached 20.18% and that of CO reached 46.55%. It was found that the catalytic performance of the pre-built carbon modified ZSM-5 sieve was mainly affected by the B acid/L acid ratio, and the pre-built carbon covered some B acid sites on the ZSM-5 sieve, which reduced the B acid/L acid ratio and led to an increase in the benzene conversion, while the crystalline and pore structures of the pre-built carbon modified ZSM-5 sieve did not undergo significant changes. changed significantly. In order to better understand the deactivation mechanism of the carbon-modified ZSM-5 catalyst, TG-MS, Raman and GC-MS were used to further analyze the carbon species, and it was found that the carbon species of the carbon-modified ZSM-5 molecular sieves were mainly low-temperature carbon, which was mainly due to the fact that the strong acid was partially covered by the carbon-modified composite catalyst with the reduced amount of acid, and the carbon species were alkanes, olefins, aromatics and other oligomers mainly. Soluble carbon, high-temperature carbon and graphitic carbon are less, so as to avoid the reduction of catalyst activity caused by excessive carbonisation, while the carbon species on the composite catalyst after the reaction are mainly high-temperature carbon, which is mainly because the carbon species after the reaction of the composite catalyst are mainly large-molecule aromatic hydrocarbons and olefins, and even insoluble carbon such as graphitic carbon. In addition, the deactivation mechanism of ZSM-5 molecular sieve in the alkylation reaction of benzene and syngas was speculated based on the hydrocarbon pool mechanism: in the alkylation reaction of benzene and syngas, syngas firstly forms methanol in the active site of metal oxides, and then the methanol migrates in the acidic site of the molecular sieve to generate alkylbenzene with benzene, but as the reaction proceeds, the alkylbenzene will be alkylated deeply in the molecular sieve to form heavy polycyclic aromatic hydrocarbons or graphitic. However, as the reaction proceeds, alkylbenzene will be deeply alkylated on the molecular sieve, forming heavy polycyclic aromatic hydrocarbons or graphite carbon, etc. Such substances are not easy to diffuse in the pores and will continuously cover the acid centre and pores of the molecular sieve, which will ultimately lead to catalyst deactivation.