Catalysts for glycerol hydrogenolysis: production of glycols from biomass derivatives

Abstract

The conversion of biomass and other renewable sources to higher-valued chemicals is one of the strategic goals of the 21th century. It is also a requirement concerning the challenges to be overcome related to environment and energy. Glycerol, a major byproduct of biodiesel production, is one of the main examples of low-cost, large-volume market product that can be used as a starting material for chemical transformation. The "glycerochemistry”, which search for routes to process glycerol into more valuable commodity chemical, has become an intense area of research. An industrially relevant route involves the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PG) and ethylene glycol (EG). Both chemicals are widely used for manufacturing important products, from fibers to antifreeze and pharmaceuticals. In the hydrogenolysis reaction, hydrogen gas reacts with glycerol in the presence of a catalyst in several coupled steps, producing intermediates that are finally converted to EG or 1,2-PG. It is a complex reaction that is usually carried out under high pressure of hydrogen (500-1050 psi), high temperature (180-2500C) and for long reaction times (4-20 h), and alternatives routes and optimized catalysts are still desirable for large scale applications. As part of the partnership between Brazilian Synchrotron Light Laboratory (LNLS) and OXITENO S/A, the presented project co-funded by FAPESP aims the development of selective catalysts for hydrogenolysis of glycerol to glycols and the comprehension of the physicochemical characteristic that determine their performance. One of the main parameters guiding this work is the optimization of the selectivity to EG or 1,2-PG in a batch reactor, taking into account requirements for scaling up process. Studies on model systems and reactions supported by advanced characterization of catalysts using synchrotron techniques and electron microscopies will help to speed up the understanding of the system. (AU)