Process for preparing biodegradable lubricant base oils

A process for preparation of fatty acid esters with 100 mol % selectivity as biodegradable lubricant base oils wherein the said process comprising the steps of:

• (a) providing recyclable, solid, hydrophobic, acido-basic bifunctional, phosphonate catalyst of molecular formula
• M(X)2-nYn.mH2O
• wherein X refers to phenyl phosphonate, Y refers to HPO42− or HPO32−, M refers to a metal ion, said metal being of Zr, the value of n varies from 0.2 to 1.8 and the value of m varies from 0 to 5;
• (b) contacting a fatty compound with an alcohol in a molar ratio ranging between 0.3 and 9 in presence of 3 to 10% catalyst by weight of fatty compound as provided in step (a);
• and
• (c) subjecting the reaction mixture as obtained in step (b) to a temperature in the range of 110 to 200° C. and for a period in the range of 0.5 to 8 h followed by separating the catalyst from liquid products and separating the fatty acid esters from unreacted starting materials.