RESUMO
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(4)H(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.
