1-O-Alkyl (di)glycerol ethers synthesis from methyl esters and triglycerides by two pathways: catalytic reductive alkylation and transesterification/reduction

From available and bio-sourced methyl esters, monoglycerides or oleic sunflower refined oil, the corresponding 1-O-alkyl (di)glycerol ethers were obtained in both high yields and selectivity by two different pathways. With methyl esters, a reductive alkylation with (di)glycerol was realized under 50 bar hydrogen pressure in the presence of 1 mol% of Pd/C and an acid co-catalyst. A second two step procedure was evaluated from methyl esters or triolein and consisted of a first transesterification to the corresponding monoglyceride with a BaO/Al2O3 catalyst, then its reduction to the desired glycerol monoether with a recyclable heterogeneous catalytic system Pd/C and Amberlyst 35 under H2 pressure. In addition, a mechanism for the reaction was also proposed.