Alkylation of Isobutane and Butene on BrOnsted-Lewis Conjugated Solid Superacids

摘要

A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 was synthesized by a two-step method. This B-L acid shows high acid strength, high activity, good selectivity and moderate stability in alkylation of isobutane/butene due to strong interaction between the BrOnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Under a mild reaction condition (30℃, 15-35xl0~5 Pa), the conversion of butene was maintained at 100% for 110 hours on stream and the main products were C_8 and TMP. The results of alkylation conducted under various operating conditions indicated that the activity was improved by increasing the loading content of HPW and SbF_5. The selectivity of TMP in the products was enhanced when the isobutane/butene ratio in the feedstock was increased. The existence of some intermediates was also reported.