Trimerization of isobutene over cation exchange resins: Effect of physical properties of the resins and reaction conditions

Oligomerization of isobutene was studied using several cation exchange resins to produce triisobutene that is useful feedstock for heavy alkylates and neo-acids. Trimer selectivity increased with increasing isobutene conversion. High isobutene conversion was obtained at high temperature and low space velocity using macroporous cation exchange resins having high concentration of sulfonic acid groups. Under selected conditions (isobutene WHSV: 10/hr; temperature: 70 oC; catalyst: Amberlyst-35), the isobutene was quantitatively oligomerized with ≥ 70% selectivity for trimer. The wet resin catalysts containing water or ethanol showed very high stability for the oligomerization up to about 70 hr contrary to the gradual decrease of the conversion with dehydrated catalysts. This is an abstract of a paper presented at the AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).