Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Abstract

Ethylene glycol (EG), synthesized from biomass, frequently contains refractory 1,2‐propanediol (PDO) and 1,2‐butanediol (BDO). Selective removal of PDO and BDO was realized herein by catalytic dehydration to form volatile aldehydes, ketones, and acetals. Various acidic and basic catalysts were screened under a range of conditions for the conversion of a mixture containing 73 wt % EG, 20 wt % PDO, and 7 wt % BDO. Over H‐Beta 26 zeolite, the most selective catalyst among tested, PDO and BDO conversions reached 99.1 and 99.3%, respectively, after 4 h reaction at 453 K, with separation factors over 2. The activation energies for EG, PDO, and BDO dehydration were ca. 99.3, 69.9, and 54.0 kJ/mol, respectively, accounting for the high reactivity of PDO and BDO. The dehydration largely proceeded in the micropores of H‐Beta and depended on the number of strong Brønsted acid sites, but excessively strong acid sites enhanced the polymerization of EG. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4032–4042, 2017

Production of 1,2-Cyclohexanedicarboxylates from Diacetone Alcohol and Fumarates

“…Compared to NMR spectrum of fresh EG, that of used EG contained some new unidentified peaks (Figures S17 and S18 in the Supporting Information), suggesting that EG was unstable under the investigated conditions. According to literature reports, the strong solid acids could lead to polymerization of EG at high temperature, which may be one reason for the deactivation of Amberlyst-15 resin.…”

Advances in porous and nanoscale catalysts for viable biomass conversion

“…To address this issue, a selective dehydration step catalyzed by zeolites was realized, which can convert 1,2-PDO and 1,2-BDO to volatile aldehydes, ketones, and acetals in liquid phase. 111 Micropores of H-b zeolite provide the active sites i.e. Brønsted acid sites for the selective dehydration of a mixture containing 73 wt% ethylene glycol, 20 wt% 1,2-PDO, and 7 wt% 1,2-BDO, resulting in 99% and 99.3% conversions of 1,2-PDO and 1,2-BDO, respectively.…”

Toward Replacing Ethylene Oxide in a Sustainable World: Glycolaldehyde as a Bio‐Based C2 Platform Molecule

“…In particular, MEG and 1,2‐butanediol form an azeotrope at a molar ratio of 1:1 [82] . Zhang and co‐workers have, therefore, investigated a chemical approach based on catalytic dehydration followed by subsequent acid‐induced rearrangements to separate MEG from other diols [82, 83] . This approach is based on MEG and the other diols dehydrating to aldehydes at different rates over strong Brønsted acid catalysts such as H‐Beta.…”