Acrylonitrile from Biomass: Still Far from Being a Sustainable Process

The production of acrylonitrile from biomass is in its infancy. We have reviewed the most pertinent literature in this area and find that the highest yields of acrylonitrile (60 %, on 5 cc microreactor scale) are obtained from glycerol as the biomass derived feed material. Unfortunately, because glycerol is derived from a food-biomass source, its use for industrial purposes is rather unacceptable to the general public and most governments. A more palatable biomass feed, derived from non-food sources, would be propionic acid or glutamic acid. Unfortunately, the acrylonitrile yields achieved thus far from these starting materials are rather miniscule. Yet, if in the future, a biomass based acrylonitrile process were to be desired, it will have to be based on non-food biomass derived feeds. Therefore, it will be necessary to develop novel catalysts to achieve this desired goal. With the price of crude oil being at decade low levels ($30–$35/barrel) it will be a formidable challenge for bio-based acrylonitrile processes to compete, not to mention replace, the world leading SOHIO acrylonitrile ammoxidation process using propylene as feed. In excess of 7 billion kg/year of acrylonitrile (1 kg/year for each person on earth) are produced worldwide by this process using advanced Bi-Mo-Ox based catalysts, which give acrylonitrile yields of 80+ % on commercial scale. While not impossible, it will require a great deal of scientific and engineering prowess to develop a non-food bio-based acrylonitrile process, and it will require a substantial commitment and generous subsidies from interested governments to achieve this desired goal.