Synthesis and Properties of Highly Branched Jatropha Oil Derivatives

Pure plant oil from Jatropha curcas L. is a potentially very attractive source for green chemicals [1]. It is toxic and as such does not compete with the food chain. We here report exploratory studies on the synthesis of highly branched Jatropha oil derivatives using epoxidation/dihydroxylation/esterification methodology (Scheme 1). The products may find applications as biolubricants or as cold-flow improvers in biofuel applications [2]. Two different routes were explored, i.e. esterification of epoxides (Route 1 and 4), and esterification of dihydroxyl groups (Route 2 and 5). Epoxidation was performed using a catalytic Sharpless system, dihydroxylations by either a Swern trans-dihydroxylation or an Upjohn cis-dihydroxylation. The products were characterized using NMR, GC-MS, GPC, DSC, Cloud/Pour Point Analyses (low temperature properties), and Rancimat analyses (oxidative stability). Compared to virgin Jatropha oil (pour point of about -1 to -3 oC), the branched products showed improved low temperature behaviour. The cold properties of the branched products are a function of the synthetic methodology. The compound from the route 2, 5 showed a pour point of -18 oC, whereas that of route 1, 4 was only -3 oC. Synthetic details, an overview of product properties and explanations for the differences in cold flow properties of the branched derivatives will be provided.

References
[1] Gübitz, G.M., Mittelbach, M., and Trabi, M. Bioresource Technology 67 (1999) 73-82.
[2] Kenneally, C.J. and Connor, D.S. U.S. Patent no. 6,455,716 B2.