Isolation and melting properties of branched-chain esters from lanolin

摘要

Saturated branched FA and their derivatives are both biodegradable and stable to oxidation. Their m.p. are expected to be enough lower than their straight-chain counterparts to make them ideal as biolubricants. But physical property data for branched fatty esters are limited. In this study, a complex mixture of branched methyl esters was obtained from lanolin through saponification, extraction of unsaponifiables, and methylation. Hydroxy compounds were removed by chromatography on alumina. Vacuum spinning-band distillation separated the mixture roughly by chain length. Countercurrent urea complex formation and low-temperature crystallization separated even-chain isoand odd-chain anteiso-methyl esters of chain lengths 14 through 18 at > 95% purity. Transesterification was used to convert methyl esters to isopropyl esters. The m.p. and heat of fusion of each ester were determined by DSC.NMR was used to verify the structure of branched esters.