Patent ID: 8563783

Claim:
A gas phase reaction process for converting glycerol to a product at high selectivity to propylene glycol and low selectivity to ethylene glycol, comprising: providing a gas phase reaction mixture that is essentially free of liquid and contains glycerol with a partial pressure of glycerol in a range from 0.01 bars and 0.5 bars of glycerol, and hydrogen with a partial pressure of hydrogen between 0.01 and 5 bars of hydrogen, wherein the partial pressure of glycerol in the reaction mixture is less than glycerol's dew point partial pressure in the reaction mixture, and greater than one fourth the dew point partial pressure in the reaction mixture; maintaining the reaction mixture a total pressure between 0.02 and 5 bars; contacting the reaction mixture with heterogeneous catalyst containing one or more elements of the subgroups from Group I, Group VI, and/or Group VIII of the Periodic Table at a temperature between 150° C. and 280° C. to form propylene glycol.