Catalysis of Organic..

Sanders et al. 37742. Producing Polyurethane Foamfrom Natural OilAaron Sanders, David Babb, Robbyn Prange, Mark Sonnenschein, Van Delk,Chris Derstine and Kurt OlsonAbstractThe Dow Chemical Company, 2301 N Brazosport Blvd., Freeport, TX, 77541awsanders@dow.comAs part of the effort to reduce our dependence on fossil fuels, The Dow ChemicalCompany has been developing a seed oil based polyol to be used as a replacement toconventional petrochemical based polyether polyols in the production of flexiblepolyurethane foam. The general process for making natural oil polyols consists offour steps. In the first step, a vegetable oil (triglyceride) is transesterified withmethanol, liberating glycerin, and forming fatty acid methyl esters or FAMEs. In thesecond step the FAMEs are hydroformylated giving a complex mixture of FAMEsthat contain 0-3 formyl groups per chain. In the third step, the aldehydes and theremaining unsaturates are hydrogenated to yield a mixture of FAMEs that contain0-3 hydroxymethyl groups. Finally, the poly(hydroxymethyl)fatty esters aretransesterified onto a suitable initiator to produce the natural oil polyol.IntroductionThe preparation of polyester polyols from seed oils for the production of a variety ofpolyurethane products has been previously reported (1,2). The development ofprocess and product technology that is sufficiently robust to compensate for inherentvariability in products derived from natural resources is key to successfulimplementation. Product variability is primarily due to genetic variety in feedstocksand seasonal inconsistency, such as regional rainfall totals or pests and disease.Process technology that may be applied to a wide variety of potential feedstockswould be highly desirable.Dow’s process for producing natural oil polyols consists of four steps and isshown in Figure 1. In the first step, a vegetable oil (triglyceride) is transesterifiedwith methanol, liberating glycerin and forming fatty acid methyl esters (FAMEs). Inthe second step the FAMEs are hydroformylated to create a complex mixture ofFAMEs that contain 0-3 formyl groups per chain. In the third step, the aldehydesand the remaining unsaturation are hydrogenated to yield a mixture of FAMEs thatcontain 0-3 hydroxymethyl groups. In the final step the poly(hydroxymethyl)fattyesters are transesterified onto a suitable initiator to produce the natural oil polyol.This paper will review the process, emphasizing the catalysts employed in each step.