ABSTRACT

PNNL-SA-39754 Abstract PNNL, in cooperation with the USDOE and CRADA partners, National Corn Growers Association and Archer Daniels Midland, has evaluated a new class of catalysts based on nickel and rhenium with effective performance for highly selective, high conversion hydrogenolysis of five-carbon sugar alcohols to industrially useful glycols. The Ni/Re catalyst appears to exhibit preferential reductive cleavage of the carbon-carbon bonds of secondary carbons over primary carbons of the 5-carbon sugar alcohols tested. In addition, the catalyst has demonstrated the ability to produce glycerol and 1,2-propylene glycol in a controllable ratio. The rhenium containing catalysts are found to have higher activity and better selectivity to desired glycols than previously reported catalysts. A continuous flow reactor lifetime test of over 1500 hours also demonstrated the requisite high stability for an industrially attractive process. Introduction Use of renewable resources for production of valuable chemical commodities is becoming a topic of great national interest and importance. Catalytic hydrogenolysis of sugar alcohols to glycols fits this goal. However, previous demonstrations of the chemistry mainly has been focused on six carbon sugar alcohols [1,2,3,4,5]. Five carbon sugars and their alcohols, e.g. xylitol and arabitol, while merely mentioned in many of these patents, are an attractive alternative to six carbon sugar alcohols as they are potentially inexpensive materials available from controlled hydrolysis of very cheap corn fiber and other agricultural wastes.