Transesterification of soybean oil with zeolite and metal catalysts

Transesterification of soybean oil with methanol was carried out at 60, 120, and 150degreesC in the presence of a series NaX faujasite zeolite, ETS-10 zeolite, and metal catalysts. The stock zeolites were exchanged with potassium and cesium; NaX containing occluded sodium oxide (NaOx/NaX) and occluded sodium azide (NaOx/NaX*). The catalysts were calcined at 500degreesC prior to use in order to increase activity. The ETS-10 catalysts provided higher conversions than the Zeolite-X type catalysts. The increased conversions were attributed to the higher basicity of ETS-10 zeolites and larger pore structures that improved intra-particle diffusion. Methyl ester yield increased with an increase in temperature from 60 to 150degreesC. The metal catalysts increased conversion by one to over two orders of magnitude over the homogeneous reaction with several of the zeolite catalysts performing better than the metal catalysts. The catalyst was reused without observed loss of activity. A preliminary design assessment shows that these catalysts are sufficiently active to be commercially viable contingent upon the costs of the catalysts achieving conversions in excess of 90% at temperatures below 125 degreesC. (C) 2003 Elsevier B.V. All rights reserved.