Promoting di-isobutene selectivity over ZnO/ZrO2-SO4 in isobutene oligomerization

Isooctane attracts great interest in recent years because of its promising potential as friendly-environmental gasoline, which is obtained by dimerization of isobutene with a hydrogenation step. Herein, a solid acid catalyst sulfated zirconia modified by ZnO was prepared. The oligomerization of isobutene had been investigated over ZrO 2 -SO 4 and ZnO( X )/ZrO 2 -SO 4 catalyst in order to find efficient catalysts for the production of isobutene oligomers . The presence of ZnO obviously enhanced the dimerization of isobutene and ZnO( X )/ZrO 2 -SO 4 exhibited the highest di-isobutene yield of 60%. Kinetic studies showed the higher trimerization-to-dimerization activation energy ratios of ZnO( X )/ZrO 2 -SO 4 than those of ZrO 2 -SO 4 from 353 to 393 K. In addition, reaction rate of dimerization was higher than trimerization over ZnO( X )/ZrO 2 -SO 4 . The high L/B ratio manifested the capability to enhance the selectivity of C 8 in isobutene dimerization. Furthermore, ZnO( X )/ZrO 2 -SO 4 exhibited stable conversion for the dimerization of isobutene.