Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT
 This invention was made with Government support under Contract DE-AC06-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.