Selective mono-isopropylation of 1,3-propanediol with isopropyl alcohol using heteropoly acid supported on K-10 clay catalyst

Abstract

Catalytic hydrogenolysis/hydrogenation of bioglycerol leads to 1,2 and 1,3-propanediols, which can be further valorized to industrially important products through a variety of reactions such as etherification, esterification and cyclization through acetalization. In the current work, selective mono-etherification of 1,3-propanediol (PDO) with isopropanol to 3-isopropyl-1-propanaol was systematically studied, using 20% w/w Cs_2.5H_0.5PW₁₂O₄₀/K-10 catalyst in an autoclave at 170 °C. In a typical reaction, using 1:6 mol ratio of 1,3-PDO to isopropanol at 0.03 g/cm³ catalyst loading and 1000 rpm, 60% conversion was achieved with 100% selectivity to the product. The catalyst was prepared by incipient wetness technique and characterized by various techniques such as X-ray diffraction, surface area measurement by N₂ adsorption–desorption, FTIR, and SEM. Effect of various reaction parameters on conversion and selectivity was studied to establish kinetics and mechanism. The catalyst is robust and reusable. The overall process is green and clean.