Selective Dehydration of Polyols to Commodity Chemicals

Synthesis of commodity chemicals from biorenewable sources is an important component of a sustainable society. Due to the very different chemical nature of bio-based feedstocks, a fundamental understanding of the chemical conversion of bio-derived molecules will be necessary for production of biorenewable chemicals. One reaction of interest for biorenewable chemicals is the selective removal of oxygen from polyols. In this presentation, acid-catalyzed dehydration of a biorenewable model compound, 1,2,6-hexanetriol, to selectively produce precursors of 1,6-hexanediol, which is a large volume commodity chemical, will be discussed. To investigate the fundamental chemistry pathways leading to the desired product, the model compound was converted via gas phase dehydration over a wide variety of heterogeneous acid catalysts. Acid strength was found to have an important effect on activity regardless of catalyst morhphology, but did not necessarily impact selectivity. Interestingly, a pathway to ε-caprolactone was found, which is proposed to be through an intermediate generated in the reaction. This talk will include a discussion of catalytst properties leading to selective dehydration of the polyol, proposed reaction mechanisms and initial results from mechanistic studies. Finally, possible catalyst surface effects and self-reactions that could be applied to other polyol systems will be presented.