Reactions of gaseous H atoms with propylene oxide monolayers adsorbed on graphite covered Pt(111) surfaces

Monolayers of propylene oxide were prepared on graphite monolayers an Pt(11 1) surfaces at 90 K and their reactions with gaseous H(D) atoms investigate d using TDS and HREELS. I-propanol, n-propanol, acetone, water, propane, an d propene were observed as reaction products. This rich chemistry is possib le since Il addition to propylene oxide leads to two radical intermediates via splitting of the C-O-C ring on either side of the oxygen. H addition to these radicals results in overall alcoholysis of propylene oxide. N-propan ol is favored as a product over i-propanol due to the higher stability of t he intermediate. Alternatively, via split-off of water, propene is formed f rom the radicals. These primary products undergo further reactions with H a toms: propene is hydrogenated towards propane, i-propanol reacts via a sequ ence of two H-abstractions to acetone. The reaction cross-section of H addi tion to propylene oxide of only 0.03 Angstrom(2) indicates that the ring sp litting is compatible with a direct, Eley-Rideal type reaction, (C) 1999 El sevier Science B.V, All rights reserved.