Efficient and green synthesis of biological wax mono esters

Biological wax monoesters are important commercial products used in various industrial and medicinal fields. Obtaining these valuable compounds from sperm whale is prohibited, and some tropical plant sources are used to obtain these esters. Therefore, these valuable compounds can be synthesized via several chemical and enzymatic reactions which have some advantages and more disadvantages. In the present study easily accessible [C16ImSO3H]Cl was screened as a Brønsted acid metal free catalyst for the chemical esterification or transesterification of equimolar amounts of long chained fatty acids or fatty acid methyl esters respectively with fatty alcohols in solventless medium. The various parameters affecting the yield of the wax ester were optimized, catalyst reuse and large scale synthesis was also carried out. According to this alternative practical and green process, a series of wax esters (17 examples) were produced readily in good to excellent yields. There was no undesirable geometric cis-trans isomerization in unsaturated fatty acids under the reaction conditions used. The catalyst is also quite effective when triglycerides are converted directly to the wax esters via transesterification reaction.