Aqueous phase hydrogenolysis of glycerol to bio-propylene glycol over Pt-Sn catalysts

Abstract

PtSn supported on SiO 2 obtained via surface organometallic chemistry techniques catalyzes hydrogenolysis of glycerol to obtain bio-propylene glycol (PG). Bimetallic catalysts with Sn contents between 0.1% and 1% wt were carefully prepared by selective hydrogenolysis of Sn(n-C 4H 9) 4 on Pt. TEM, TPR, H 2 and CO chemisorptions, and XPS studies have shown that tin selective deposition on the metallic phase is obtained. At 200°C under N 2 or H 2 pressure, the presence of tin increases drastically: both the selectivity and the activity of the glycerol conversion into PG. During 2h batch runs; it could be observed that PtSn catalysts with Sn/Pt ratio=0.2 showed the best performance (PG selectivity=59% and 83% under N 2 and H 2 pressure respectively). The increase in activity and selectivity could be explained by the presence of Sn +n species "acid Lewis sites" which would facilitate the C-OH adsorption and its subsequent C-O cleavage favoring the propylene glycol production.