Reactivity of crotonaldehyde and propene over Au/Pd(111) surfaces

Abstract

The surface chemistry of crotonaldehyde and propene, primary and secondary reaction products in the aerobic selective oxidation of crotyl alcohol, has been studied by temperature-programmed reaction over Au/Pd(111) surface alloys. Gold strongly promotes desorption versus reaction at mole fractions ≥0.3 (crotonaldehyde) and ≥0.8 (C₃H₆); only ∼5% of the chemisorbed aldehyde or alkene react over Au-rich alloys. Surprisingly, co-adsorbed oxygen strongly suppresses crotonaldehyde decomposition over both clean Pd(111) and alloy surfaces, while C₃H₆ combustion, an important undesired side-reaction over unpromoted Pd(111), is also moderated by Au.