Selective Synthesis of Fatty Alcohols over Mild Reaction Conditions via Non-Catalytic Liquid-Phase Fatty Acid Methyl Esters’ Reduction

ALEJANDRO VALLEJO ORREGO; CRISTIAN FERRETTI; VERONICA DIEZ

Chemistry Proceedings

Multidisciplinary Digital Publishing Institute (MDPI)

Año: 2023 vol. 14

The upgrading of fatty alcohols synthesis from natural fatty acid methyl esters’ reduction using alumina-supported NaBH4 without H2 supply was investigated. It was possible to synthesize fatty alcohols efficiently with high yields. By using pure NaBH4 or alumina-supported NaBH4 and methanol as co-reactants, 100% selectivity towards fatty alcohols was achieved. The purpose of supporting the metal hydride is to increase its stability and ensure the recovery of the product at the end of the reaction. A high final fatty alcohol yield was obtained when alumina-supported NaBH4 was used. The use of more than stoichiometric amounts of methanol and NaBH4 is important to produce alkoxyborohydride anions that act as better reducing species than NaBH4. The reaction conditions effect was investigated and the role of short carbon chain alcohol structure was explained. The effect of fatty acid methyl ester structure was also examined. Saturated fatty acid methyl esters (methyl laurate, methyl myristate) with short carbon chains can be easily reduced using NaBH4/Al2O3 and methanol, thus obtaining high conversion and selectable fuel alcohol. Unsaturated fatty acid methyl ester (methyl oleate) with longer carbon shows steric hindrance, which is not suitable for the interaction of esters and reduces the surface area, meaning that the conversion of fatty acid methyl ester is lower.