One-pot catalytic production of 1, 3-propanediol and γ-valerolactone from glycerol and levulinic acid

Abstract

1,3-propanediol (1,3-PDO) and γ-valerolactone (GVL) were simultaneously obtained via the hydrogenolysis of glycerol in levulinic acid (LA) using Ru/C catalysts. Ru/C catalyst exhibited a high LA conversion (∼99%) and a high GVL selectivity (∼99%) for the hydrogenation of LA; while a low conversion (∼11%) and little selectivity of 1,3-PDO for the hydrogenolysis of glycerol. LA promoted the hydrogenolysis of glycerol over Ru/C catalyst, in which LA catalyzed dehydration of glycerol into acetol (precursor of 1,2-propanediol (1,2-PDO)), and glycerol acetalization with the hydrogenated GVL into cyclic acetals, resulting in the formation of 1,3-PDO. A reaction scheme involves the formation of cyclic acetal ethers between GVL and glycerol was proposed to explain the product distributions in the one-pot synthesis of 1,3-PDO and GVL. 64.5% conversion of glycerol and 35.8% selectivity of 1,3-PDO together with 99.1% conversion of LA and 85.8% selectivity of GVL were obtained during one-pot converting glycerol and LA with 3.0MPa H2 at 200°C for 6h. We reported an effective strategy for the preparation of 1,3-PDO by selective hydrogenolysis of dioxan originated from glycerol with aldehydes or ketones.