The Biodiesel Factor
Preceding the development of biobased PG was the broad effort in the 1990s to replace petroleum products with fuels from renewable sources, such as ethanol as a supplement for gasoline. A prime target was a biobasedreplacement for diesel fuel. Because diesel yields better mileage than comparable gasoline engines, it has long been popular for long-distance transportation — more than 90 percent of freight is shipped in diesel-powered trucks, trains and boats.
Flexible Feedstocks
The PNNL/ADM team did better. PNNL’s initial focus was a catalyst that would make PG from sorbitol, but it turned out it could make PG out of glycerol as well. ADM joined the project, both in research and funding, with an immediate goal of developing a formula that would enable commercialization. They ended up working on the glycerol byproduct from biodiesel.
“The ADM team participated in additional collaborative work to improve the technology,” Lund notes, “and once they felt it would be commercially deployable, we entered into a licensing agreement with the company in 2006 granting them rights to manufacture propylene glycol.”
Adds Bloom: “We went with glycerol as our initial starting point but we approached the research targeting a number of potential sources, including corn sugars. Our goal for the long-term is to be able to work with flexiblefeedstocks — not just glycerol but also multiple carbohydrates including sucrose, dextrose, carbohydrates, corn stover and other cellulosic feedstocks.”