Isomerization of c<i>is</i>-2,5-Di(hydroxymethyl)tetrahydrofuran to its t<i>rans</i>-Isomer and the Effect of the c<i>is</i>/t<i>rans</i> Ratio on the Properties of its Polyester with 1,12-Dodecanedioic Acid

2,5-Di(hydroxymethyl)tetrahydrofuran (DHMTHF) was prepared by the Raney-nickel-catalyzed hydrogenation of biobased 5-hydroxymethylfurfural. It was obtained as mainly the cis isomer which could be partially converted to its trans isomer via a ruthenium-catalyzed borrowing hydrogen-type reaction. After acetylation of the cis/trans-DHMTHF mixture, the trans isomer was found to selectively precipitate from a diethyl ether solution at −15 °C. DHMTHF was used as a polyol building block, and the influence of its stereochemistry on the properties of polyester polyols and polyurethanes (PUs) that are suitable for adhesive applications was investigated. A polyester polyol derived from 100% biobased material was prepared using dodecanedioic acid. The polymer with a high trans isomer content (85%) exhibited a higher crystallinity than the two polyester polyols containing a lower amount of the trans isomer. In contrast, the PU synthesized from the cis/trans (57/43) DHMTHF-derived polyester polyol showed superior mechanical properties as compared to those of the corresponding PUs containing cis- and trans-enriched analogues.