Highly Selective Production of Renewable 1,3-Pentadiene from 1,4-Pentanediol over an Acid–Base (K–Ce/ZrSi) Catalyst by Adjusting the Parallel-Reaction Pathway

Selective synthesis of 1,3-pentadiene without 1,4-pentadiene formation is challenging as well as rewarding because of the widespread use of 1,3-pentadiene in adhesive, paint, and curing agent production. Herein, modified K–Ce/ZrSi catalysts with acid–base sites were synthesized for the production of 1,3-pentadiene from 1,4-pentanediol. The overall 1,3-pentadiene yield was 74.7%, while the 1,4-pentadiene yield was 1.3%. On the catalyst, two parallel routes (direct dehydration and dehydra-decyclization) for the conversion of 1,4-pentanediol to 1,3-pentadiene were disclosed. The 4-position hydroxyl group was first activated and then eliminated on the acid sites. It was considered that the acid–base sites of catalysts exhibited a synergistic effect for the selective dehydration of 1,4-pentanediol to 1,3-pentadiene, where the medium strength Lewis acid sites and weak base sites were responsible for the elimination of the hydroxyl group and the corresponding β1-H, thereby inhibiting the formation of 1,4-pentadiene. Furthermore, a plausible reaction network was proposed.