Hydrolysis of vegetable oils and fats to fatty acids over solid acid catalysts

Solid Fe-Zn double-metal cyanide (DMC) complexes exhibit high catalytic activity for hydrolysis of edible and non-edible vegetable oils and animal fat. In a batch reaction, complete conversion of vegetable oil triglycerides to fatty acids with selectivity greater than 73 wt% was obtained at temperatures as low as 463 K, autogenous pressure and with 5 wt% of catalyst. Catalytic activity of DMC was superior to Amberlyst™70, SAPO-11, H-β, HY, MoOx/Al2O3 and sulfated zirconia. Rates of hydrolysis were greatly enhanced when solvents (tetrahydrofuran or N,N-dimethylformamide), phase transfer agents (tetrapropyl ammonium bromide) and products (a mixture of mono-/diglycerides and fatty acids) or fatty acid was added to the feed. Surface hydrophobicity which enables high wettability and activation of glycerides on active, acidic sites of reusable DMC is attributed to be the major cause for its superior catalytic activity.

Graphical abstractSolid Fe-Zn double-metal cyanide (DMC) complex exhibits high catalytic activity for hydrolysis of vegetable oils and animal fat. Complete conversion of oil with fatty acids selectivity >73 wt% was obtained at temperatures as low as 463 K and autogenous pressure. Superior activity of DMC compared to known solid acid catalysts is attributed to its surface hydrophobicity.Figure optionsDownload full-size imageDownload high-quality image (53 K)Download as PowerPoint slide