Combining Bio- and Chemo-Catalysis for the Conversion of Bio-Renewable Alcohols: Homogeneous Iridium Catalysed Hydrogen Transfer Initiated Dehydration of 1,3-Propanediol to Aldehydes

Authors: Yue-Ming Wang,a,b Fabio Lorenzini,a Martin Rebros,c Graham C. Saunders,d
and Andrew C. Marr.a,b

a School of Chemistry and Chemical Engineering, Queen’s University of Belfast, UK.
b Queen’s University Ionic Liquids Laboratories (QUILL), UK.
c Institute of Biotechnology and Food Science, Faculty of Chemical and Food Technology,
Slovak University of Technology, Bratislava, Slovakia.
d School of Science, The University of Waikato, Hamilton 3240, New Zealand.

Type of publication: Article
Date: November 2015
Journal: Green Chemistry, 2015, DOI: 10.1039/C5GC02157J
Main partner: QUB and STUBA

Abstract: Combining whole cell biocatalysis and chemocatalysis in a single reaction sequence
avoids unnecessary separations, and the associated waste and energy consumption. Bacterial
fermentation has been employed to convert waste glycerol from biodiesel production into
1,3-propanediol. This 1,3-propanediol can be extracted selectively from the aqueous
fermentation broth using ionic liquids. 1,3-propanediol in ionic liquid solution was converted
to propionaldehyde by hydrogen transfer initiated dehydration (HTID) catalysed by a
Cp*IrCl2(NHC) (Cp* = pentamethylcyclopentadienyl; NHC = carbene ligand) complex. The
use of an ionic liquid solvent enabled the reaction to be performed under reduced pressure,
facilitating the isolation of the product, and improving the reaction selectivity. The Ir(III)
catalyst in ionic liquid was found to be highly recyclable.

The paper is available in the Royal Society of Chemistry website here.