Catalytic Hydrogenolysis of Solketal on Bifunctional Catalysts with Production of High Octane Components of Motor Fuels

Abstract

The possibility of implementing the concept of converting bioglycerin into a blend of oxygenates, potentially applicable as components of gasoline by ketalization with acetone (T = 30–40°C, atmospheric pressure), accompanied by mild hydrogenolysis of ketal [T = 100–140°C, p(H2) = 2 MPa] to obtain a mixture of of glycerol and solketal isopropyl ethers. It was shown that the preferred method of conversion is the separate performing of ketalization and hydrogenolysis, since when these stages are combined, the side reaction of the formation of free isopropyl alcohol is highly selective. The regularities in the influence of the composition of the catalytic system (Pd/C + para-toluenesulfonic acid) on its activity were found in the reaction of catalytic hydrogenation of solketal to a mixture of glycerol and solketal isopropyl ethers (optimal ratio of Pd/para-toluenesulfonic acid = 0.811 mol). It was shown that the addition of 4–5% glycerol to raw materials makes it possible to increase the yield of target hydrogenation products from 25 to 36%. Using a flow unit, the catalytic hydrogenation of solketal was optimized. In the optimal mode [T = 170°C, p(H2) = 4 MPa, v = 0.5 h−1, H2/feedstock = 660 nL L−1], the conversion of solketal to a mixture of target products (glycerol monoisopropyl ether, glycerol diisopropyl ethers, and solketal isopropyl ether) reaches 98%. The possibility of carrying out the reaction on heterogeneous bifunctional catalysts of the Pd/sulfonated coal type is shown.