(160b) Heterogeneous Catalytic Activities Of Anion Exchange Resins On The Transesterification Of Soybean Oil With Methanol
Traditional fossil energy resources are limited. One of the promising approaches is the conversion of vegetable oils. Most of the commercial biodiesel comes from the transestrification of soyoil using caustic homogeneous base catalysts. Although homogeneous processes are relatively fast, they are still not fully cost-competitive because of the purification cost and side reaction caused by caustic catalysts dissolved in the products In order to solve these problems, the development of insoluble and reusable heterogeneous catalyst is required. Anion exchange resins were tested as heterogeneous base catalysts in the transesterification of soybean oil with methanol. The catalytic activities of the resins were measured by the yield of the fatty acid methylester in the products with a GC-mass spectrometer. All of the anion-exchange resins catalyzed the transesterification and produced fatty acid methyl esters. Especially, the resins of type I (DOWEX marathon A , MSA, and SBR LCNG) having benzyl-trimethylamine functionality showed very good catalytic activities compared to the resin of type II having benzyl-dimethylethanolamine (DOWEX 22) or polyamines functionalities (Weak base anion exchanger: Marathon WBA). Transestrification reactions were completed after 13hr at 55°C when 10g of type I resin catalysts were used in the mixture of 10.8g methanol and 30.0g of soybean oil. However, 76% conversion was obtained from the weak base anion exchanger (Marathon WBA) at the same condition. A new ion exchange method using a NaOH solution (1.0M) in methanol instead of aqueous solution of NaOH was attempted in order to eliminate the negative effects of water on the deactivation of catalyst and side reactions. Catalytic activities of anion exchange resins that are different in base strength, degree of cross-linking, matrix structure, and particle sizes will be discussed.