Selective hydroxyalkoxylation of epoxidized methyl oleate by an amphiphilic ionic liquid catalyst

Authors: Winfield, Demichael; Moser, Bryan

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2022
Publication Date: 12/13/2022
Citation: Winfield, D.D., Moser, B.R. 2023. Selective hydroxyalkoxylation of epoxidized methyl oleate by an amphiphilic ionic liquid catalyst. Journal of the American Oil Chemists' Society. 100(3):237-243. https://doi.org/10.1002/aocs.12672.
DOI: https://doi.org/10.1002/aocs.12672

Interpretive Summary: Oleic acid is a naturally occurring fatty acid found in plant oils. It has been used as a biobased starting material for fuels, plastics, and many other materials. Harsh chemicals are generally used to modify oleic acid so that it can be used for different applications. In this work, we employed an ionic liquid for modifying oleic acid. Ionic liquids are greener and a more environmentally sustainable catalyst compared to their conventional counterparts. The products obtained from our ionic liquid catalyst were comparable to or better than the products obtained from less environmentally friendly catalysts. These results provide a more sustainable method for modifying biobased compounds.

Technical Abstract: Oleic acid is an attractive biobased platform chemical. Precursors for biobased materials can be accessed by epoxidation and subsequent hydroxyalkoxylation of oleic acid. The hydroxyalkoxylation step is conventionally performed with sulfuric acid or a metal catalyst. Due to their high polarity, many ionic liquid catalysts are ineffective for hydroxyalkoxylation of fatty acid derivatives with non-polar alcohols. In this work, we utilized an amphiphilic ionic liquid catalyst to perform hydroxyalkoxylations of epoxidized methyl oleate. An ionic liquid catalyst based on dimethyl lauryl amine was synthesized and evaluated for this reaction due to its long alkyl group. The amphiphilic nature of the ionic liquid allowed for better miscibility and reactivity compared to other ionic liquids. Several alcohols were used with high yields (greater than or equal to 80%) and selectivity (greater than or equal to 92%), including nonpolar alcohols with longer alkyl chains such as octanol and dodecanol. The high selectivity of these conditions could be advantageous for applications in lubricants, biofuels, or polyol preparation. This work demonstrates a greener alternative to conventional hydroxyalkoxylation catalysts.