Selective hydroconversion of coconut oil-derived lauric acid to alcohol and aliphatic alkane over MoOx-modified Ru catalysts under mild conditions

Abstract

Molybdenum oxide-modified ruthenium on titanium oxide (Ru–(y)MoO_x/TiO₂; y is the loading amount of Mo) catalysts show high activity for the hydroconversion of carboxylic acids to the corresponding alcohols (fatty alcohols) and aliphatic alkanes (biofuels) in 2-propanol/water (4.0/1.0 v/v) solvent in a batch reactor under mild reaction conditions. Among the Ru–(y)MoO_x/TiO₂ catalysts tested, the Ru–(0.026)MoO_x/TiO₂ (Mo loading amount of 0.026 mmol g⁻¹) catalyst shows the highest yield of aliphatic n-alkanes from hydroconversion of coconut oil derived lauric acid and various aliphatic fatty acid C6–C18 precursors at 170–230 °C, 30–40 bar for 7–20 h. Over Ru–(0.026)MoO_x/TiO₂, as the best catalyst, the hydroconversion of lauric acid at lower reaction temperatures (130 ≥ T ≤ 150 °C) produced dodecane-1-ol and dodecyl dodecanoate as the result of further esterification of lauric acid and the corresponding alcohols. An increase in reaction temperature up to 230 °C significantly enhanced the degree of hydrodeoxygenation of lauric acid and produced n-dodecane with maximum yield (up to 80%) at 230 °C, H₂ 40 bar for 7 h. Notably, the reusability of the Ru–(0.026)MoO_x/TiO₂ catalyst is slightly limited by the aggregation of Ru nanoparticles and the collapse of the catalyst structure.