New catalysts for carboxylation of propylene glycol to propylene carbonate via high-throughput screening

José A. Castro-Osma, James W. Comerford, Richard H. Heyn*, Michael North, Elisabeth Tangstad

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


High throughput methodologies screened 81 different metal salts and metal salt combinations as catalysts for the carboxylation of propylene glycol to propylene carbonate, as compared to a 5 mol% Zn(OAc)2/p-chlorobenzene sulfonic acid benchmark catalyst. The reactions were run with added acetonitrile (MeCN) as a chemical water trap. Two new catalysts were thereby discovered, zinc trifluoromethanesulfonate (Zn(OTf)2) and zinc p-toluenesulfonate. The optimal reaction parameters for the former catalyst were screened. Zn(OTf)2 gave an overall propylene carbonate yield of greater than 50% in 24 h, twice as large as the previous best literature yield with MeCN as a water trap, with 69% selectivity and 75% conversion of propylene glycol at 145 °C and 50 bar CO2 pressure.

Original languageEnglish
Pages (from-to)19-30
Number of pages12
Publication statusPublished - 23 Sept 2015

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