Catalyst Design for Shape Selective Methylation of 2-Methylnaphthalene

研究了2-甲基萘与甲醇的形状选择性烷基化反应制备2,6-二甲基萘。在各种沸石中，MFI型沸石ZSM-5对2,6-二甲基萘具有较高的选择性。因此，对HZSM-5分子筛与MFI结构的金属硅酸盐进行了详细的烷基化反应研究。对具有MFI结构的催化剂进行了改性，改变了催化剂的酸强度和孔径。此外，还对催化剂进行了单外表面失活改性。2,6-二甲基萘在硅铁表面的形成具有很高的选择性，特别是当表面选择性地被2,4-二甲基喹啉毒害时。此外，为了制备高性能的选择性生成2,6-二甲基萘的催化剂，降低酸强度是有效的，保持MFI结构的孔径恒定，如果可能的话，扩大孔径。

Shape selective alkylation of 2-methylnaphthalene with methanol to produce 2,6-dimethylnaphthalene was studied. Among various zeolites, MFI type zeolites, ZSM-5, exhibited a high selectivity to 2,6-dimethylnaphthalene. Therefore, detailed study on the alkylation over HZSM-5 zeolites and metallosilicates with MFI structure was carried out. The catalysts with MFI structure were modified to vary the acid strength and pore dimension. Moreover, the modification of the catalysts for inactivation of solely external surfaces of zeolite crystallites was performed. A high selectivity for the formation of 2,6-dimethylnaphthalene was achieved on ferrisilicate especially when the external surfaces were selectively poisoned by 2,4-dimethylquinoline. Moreover, in order to prepare a high performance catalysts for selective formation of 2,6-dimethylnaphthalene it is effective to weaken the acid strength keeping the pore dimension of MFI structure constant, or if possible, wider.