应用分子模拟技术研究了甲苯歧化反应中的产物二甲苯各同分异构体在MFI、MEL和CAN分子筛孔道中的扩散特性,得到二甲苯各同分异构体与不同分子筛之间的相互作用能,以及吸附位和扩散特性等相关信息。计算结果表明,吸附质分子扩散的难易程度受到孔径和孔道结构的共同影响。MFI分子筛对于p-xylene有很好的选择性,不论是直孔还是弯孔,均有此特性,但弯孔中的扩散能垒较直孔中高,因此吸附质分子更倾向于在MFI分子筛直孔中进行扩散；MEL分子筛的孔径略小于MFI分子筛,各吸附质的扩散能垒较在MFI分子筛孔道中高,二甲苯各同分异构体中p-xylene的扩散能垒远小于m-xylene和o-xylene,因此,MEL分子筛也表现出对于p-xylene的选择性；在CAN分子筛的孔道中,二甲苯各种同分异构体的扩散能垒按p-xylene＜m-xylene＜o-xylene的顺序依次升高,但由于数值整体偏低,所以CAN分子筛不能够表现出对于p-xylene的择形性。 Molecular dynamics simulation was used to study the diffusion properties of xylene isomers in the toluene disproportionation reaction in the MFI, MEL and CAN molecular sieves. The interaction between isomers of xylene and different molecular sieves was obtained Can, and adsorption sites and diffusion characteristics and other related information. The calculation results show that the difficulty of diffusing adsorbate molecules is affected by the pore size and pore structure. MFI molecular sieve has good selectivity for p-xylene, both straight and curved, but the diffusion barrier in curved hole is higher than that in straight hole. Therefore, The pore size of MEL molecular sieve is slightly smaller than that of MFI zeolite. The diffusion barrier of each adsorbate is higher than that of MFI zeolite. The diffusion barrier of p-xylene in each isomer of xylene is much smaller than that of m-xylene and Therefore, the molecular sieves of MEL also show the selectivity to p-xylene. In the channels of CAN molecular sieves, the diffusion barriers of various isomers of xylene are in the order of p-xylene