The present paper describes the use of an easily accessible polymer-grafted sulfonated carbon composite catalyst for the synthesis of α-hydroxy ethers as bio-lubricants from waste vegetable oil via chemical modification involving esterification, epoxidation, and ring-opening reaction. A variety of α-hydroxy ethers were synthesized using different fatty alcohols for the evaluation of physicochemical properties. The bio-lubricants synthesized from 2-ethyl hexanol and dodecanol were found to be most promising as they exhibited lower pour point (< − 27 °C) and higher viscosity index (VI) 97 and 143, respectively. High VI and a lower pour point indicate ROP-3 and ROP-5 to be the most promising candidates as bio-lubricant for various applications.