Glycerol upgrading by ketalization in a zeolite membrane reactor

Solketal, a valuable green solvent, has been produced from glycerol and acetone in a catalytic system, using K 10 montmorillonite as a heterogeneous catalyst. The use of a zeolite membrane to remove water formed during the reaction gives rise to a significant improvement in the achievable glycerol conversion with a reduction in the excess of acetone needed because of the low equilibrium constant. Several zeolite membranes are compared, showing that the quality of the membrane is a key factor for this improvement, and that water/acetone separation is more difficult to achieve than the commonly used ethanol/water separation test. This method is compatible with a mixture of glycerol and fatty esters, showing the possible future application in an integrated system of biodiesel and solketal production. (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.