Dow Plans Propylene Glycol From Renewable Feedstock

Dow Chemical plans to start making propylene glycol from a renewable raw material rather than from the propylene oxide it uses today.

More than 1 billion lb of propylene glycol are consumed in the U.S. each year in everything from pet food to aircraft deicing fluids. Dow will use what it calls "breakthrough technology" to manufacture it from glycerin generated during the manufacture of biodiesel. Glycerin is also known as 1,2,3-propanetriol, whereas propylene glycol is 1,2-propanediol.

The company refers to the new product as propylene glycol renewable, or PGR, because the glycerin raw material is created as a by-product when vegetable and seed oils such as soybean, sunflower, and canola are transesterified into the blend of methyl esters known as biodiesel. Propylene oxide, in contrast, is produced from the petrochemical propylene.

Dow says it has contracted with its Dow Haltermann Custom Processing business to carry out the conversion at a facility in Houston. The company says it is conducting PGR trials with customers and anticipates having limited commercial quantities available in mid-2007.

"Using PGR will enable customers to exercise their commitment to technologies that consume less fossil fuel and other finite resources," says Mady Bricco, Dow's global product director for propylene oxide and propylene glycol.

Dow calls itself the world's largest producer and marketer of propylene glycol. Another propylene glycol producer, Huntsman Corp., has said it is exploring making the chemical from glycerin. In addition, the agribusiness companies Cargill and Archer Daniels Midland have both announced plans to make propylene glycol from glycerin.

All of these companies are responding to rapid growth in biodiesel production throughout the world, which has created a surplus of glycerin. Although glycerin has numerous direct applications, companies now have the incentive to use it as raw material for other products. Dow and Solvay, for example, have both announced plans to build plants that make the epoxy raw material epichlorohydrin out of glycerin rather than allyl chloride.