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Synthesis of isoidide through epimerization of isosorbide using ruthenium on carbon.

ChemSusChem (2013-03-05)
Jérôme Le Nôtre, Jacco van Haveren, Daan S van Es
ABSTRACT

A highly efficient procedure for obtaining resin-grade isoidide through catalytic epimerization of isosorbide using a ruthenium-on-carbon (Ru/C) catalyst is reported. A comprehensive reaction-parameter variation study involving substrate concentration, catalyst (type of metal, support, and loading), initial pH value, hydrogen pressure, solvent, and reaction temperature demonstrates that superior performance and high selectivity can be achieved. Epimerization of isosorbide in water (pH 8) at 220 °C, under 40 bar of hydrogen, and using a Ru/C catalyst (5 % Ru) for 2 h results in a thermodynamic equilibrium mixture containing 55 % isoidide, 40 % isosorbide, and 5 % isomannide. In comparison with previously reported nickel-based catalysts, the Ru/C catalyst is advantageous because it is highly active (as low as 360 ppm Ru) and recyclable. High purity isoidide is obtained by high-vacuum distillation of an equilibrium mixture on a 200 g scale. The high substrate loading (50 wt % in water), high selectivity, and the possibility for substrate reuse makes this procedure highly atom efficient and therefore, highly attractive for industrial use.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ruthenium, powder, 99.99% trace metals basis
Sigma-Aldrich
Ruthenium, powder, −200 mesh, 99.9% trace metals basis
Sigma-Aldrich
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Sigma-Aldrich
Dianhydro-D-glucitol, 98%
Sigma-Aldrich
Ruthenium black