PNNL Provides Catalyst to Sustainable Propylene Glycol Production

PNNL Provides Catalyst to Sustainable Propylene Glycol Production

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Propylene glycol is used to manufacture chemicals that are needed to produce industrial and consumer products found in every household in America and beyond. Liquid detergents, antifreeze, deicers, paints, polyesters, cosmetics, personal care products, pharmaceuticals, and even certain food additives, things we use every day, all contain propylene glycol.

And, until recently, propylene glycol has been dependent on a nonrenewable source, petroleum, for its production. In fact, each year over two billion pounds of petroleum are consumed to make enough propylene glycol to meet worldwide demand.

Now, propylene glycol can be cost-effectively made from renewable sources using a new catalytic process developed at Pacific Northwest National Laboratory (PNNL) and commercialized by Archer Daniels Midland Company (ADM).

This new safe, sustainable, cost-competitive, and commercially viable alternative to petroleum-based propylene glycol production, called the propylene glycol from renewable sources, or PGRS process, converts plant-based glycerol or plant sugar alcohols to propylene glycol, which can then be purified to meet a variety of market specifications. The feedstock for this new process is primarily derived from the processing of a variety of crops, including corn and oilseed crops such as soybeans, sunflowers, jatropha, and Canola¨, as well as from crop residues.

Another excellent source of raw materials for the PGRS process is the glycerol byproduct from biodiesel production. For every 100 pounds of biodiesel produced, 10 pounds of glycerol are formed. The PGRS process can use this byproduct glycerol as feedstock to produce propylene glycol, a more valuable commodity. This adds significant value to the biodiesel production process, the current U.S. market for which is estimated at one to two billion pounds per year.

Development of the PGRS process began a decade ago with a Cooperative Research and Development Agreement (CRADA) between PNNL and the National Corn Growers Association (NCGA). The collaboration, which was intended to explore a possible process to convert sorbitol to propylene glycol and ethylene glycol, resulted in the development of a new set of catalysts to test for the proposed process. In doing so, the researchers discovered they were able to convert glycerol to propylene glycol, an exciting result that would enable production of propylene glycol entirely from renewable sources.

Although NCGA exercised its option rights and executed a license for the process, it became clear on the heels of this discovery that a commercial partner from the chemical manufacturing sector would be best suited to bring such a product to market. One of the PNNL scientists then introduced ADM to the collaboration.

After a large-scale collaborative effort to optimize the catalyst, PNNL technology transfer staff reached an agreement with NCGA to regain rights to the intellectual property they had licensed, including appropriate compensation to recognize NCGA's early role, so that work with ADM could continue toward a commercial end.

Around this time, direct funding from the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy was obtained to accelerate the research with an intensified focus, along with a new CRADA between ADM and PNNL beginning in 2006, on exploring viable ways to bring the process to market. During that same year, ADM licensed the process from Battelle, which operates PNNL for DOE.

The company constructed and operated a pilot plant in 2009, followed by construction of a full-scale production facility in Decatur, Illinois, for the sole purpose of commercially producing PGRS. The new manufacturing facility, which has an annual production capacity of 200 million pounds, was officially commissioned in 2011, and is now producing propylene glycol that meets USP specifications entirely from renewable sources.

Overall, using glycerol-derived propylene glycol from the PGRS process in place of petroleum-derived propylene glycol represents a significant contribution to reducing U.S petroleum consumption and, ultimately, our nation's dependence on foreign oil.

PNNL won a 2011 FLC Award for Excellence in Technology Transfer for the PGRS process, and shares a 2010 R&D 100 award from R&D Magazine with ADM.