Submitted to: Organic Process Research & Development
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/23/2014
Publication Date: 7/23/2014
Publication URL: http://handle.nal.usda.gov/10113/61132
Citation: Schweitzer, D., Mullen, C.A., Boateng, A.A., Snell, K. 2014. Bio-based n-butanol prepared from poly-3-hydroxybutyrate: optimization of the reduction of n-butyl crotonate to n-butanol. Organic Process Research & Development. 19:710-714. Interpretive Summary: The petroleum refinery produces a large number of products including fuels, chemicals and chemical building blocks for plastics and other materials. Because of the social and environmental issues associated with petroleum recovery, transportation and usage including energy security and climate change concerns, biobased alternatives for these products are desirable. Pyrolysis, a process where a material is heated in the absence of oxygen so it does not burn, is capable of producing bio-crude oils from “cellulosic” biomass such as wood, switchgrass or agricultural byproducts. These bio-crude oils can be used as feedstocks to produce bio-fuels that are indistinguishable from petroleum based fuels or used to make bio-based chemicals. Because bio-based plastic alternatives are also of interest, switchgrass that is capable of producing a bio-degradable polyester plastic, poly-3-hydroxybutyrate, has been developed. This plastic can also be pyrolyzed and one of the products is crotonic acid, a chemical that can be converted to many other valuable chemicals, which could replace some produced form petroleum. Crotonic acid can be converted to butanol, a potential fuel or commodity chemical product via a two step chemical pathway. We screened catalysts and conditions to achieve this transformation in the highest possible yield. We found that a certain commercial copper based material could produce butanol in about 90% yield. This information will be useful to those interested in biorefining of renewable resources for fuels and chemicals.
Technical Abstract: Using metabolic engineering approaches, the biopolymer poly-3-hydroxybutyrate (P3HB) can be over-produced in organisms such as bacteria and plants such as switchgrass. Thermolysis of P3HB, either in isolated form or within biomass, yields crotonic acid. It is a potential bio-derived platform chemical, whose reduction provides n-butanol, which has value as a fuel and as a commodity chemical. Herein, we report our optimization work on the hydrogenation of the n-butyl ester of crotonic acid to n-butanol, and the potential of this chemistry to be incorporated into the production of bio-n-butanol from P3HB containing biomass.