A new catalytic process for the synthesis of para-xylene through benzene methylation with CH3Br

Progress of Methylation of C6-8~Arene with Methanol: Mechanism, Catalysts, Kinetic/Thermodynamics and Perspectives

“…It has been reported [16] that the PX selectivity can be improved by reducing the effective pore size of ZSM-5, because it could suppress the disproportionation reaction and change the product diffusion rate [49]. Tan et al [1] also considered the effects of SiO 2 , P 2 O 5 and MgO on the catalyst activity, and the results showed that the optimal pore structure was the main reason for the high selectivity of PX (Figure 10). Zheng [45] et al found that increasing the content of Pt and Pd could improve the selectivity of PX due to the reduction in pore size.…”

“…Meanwhile, the inner and outer surface acidities of the catalyst have a very important influence on the selectivity and activity of the catalyst. In situ experimental studies have shown [1,57] that the adsorption of methanol on the acid active site of zeolite can indeed generate methoxy intermediate species, which could easily be methylated with aromatic molecules. The methylation reaction is first activated by acid active sites, which show that the mesoscopic microstate of the catalyst surface is the key point for benzene activation.…”

“…At the same time, the electrostatic field generated by the cation has a certain influence on the product selectivity. Zhang [1] et al modified ZSM-5 with MgO and applied it in the methylation reaction, and the selectivity of xylene increased from 27% to 67%. It has also been reported that the modification of Mg and Ca [49] can improve the selectivity of PX due to the basicity and size of basic cations that determine its catalytic performance.…”

“…Aromatic hydrocarbon products can be widely used in synthetic resins, synthetic fibers, synthetic rubbers, detergents, plasticizers, dyes, medicines, spices, pesticides and other industries. Meanwhile, they play an important role in developing the national economy and improving people's lives [1][2][3][4][5]. Under the background of "carbon reduction", the rational distribution of light hydrocarbon and aromatic hydrocarbon industries could improve the competitiveness of PX and TMB and actively promote the realization of green, low-carbon and high-quality development of the industry.…”

Highly Effective Transformation of Methanol and RFCC Gas to Propylene and Paraxylene with Tungsten Hydride and Cerium Oxide Comodified HZSM-5 Zeolite

“…Paraxylene is one of the most valuable aromatic compounds, required as a raw material for polyester and terephthalate. The formation of paraxylene in the alkylation of toluene with methanol, the disproportionation of toluene, and the transalkylation of methylbenzenes has been studied over acidic zeolites such as ZSM-5, zeolite X, zeolite Y, mordenite, MCM-22, mesoporous aluminum silicate Al-MCM-41, and zeolite Beta. , ZSM-5 is very interesting because its pore size is suitable for separating paraxylene from a mixture of xylene isomers. The past few decades have brought many reports on the pore modification of ZSM-5 to enhance its selectivity for paraxylene and techniques for the impregnation of MgO, boron, and phosphorus.…”