Surface intermediates, mechanisms and selectivities of reactions of alcohols, aldehydes, and carboxylic acids on clean and modified palladium(111) surfaces.

摘要

he interactions of a wide range of alcohols, aldehydes, and carboxylic acids were studied on both clean and chemically-modified Pd(111) surfaces through the combined use of Temperature Programmed Desorption (TPD) and High Resolution Electron Energy Loss Spectoscopy (HREELS). The adsorbates were chosen in order to gain an understanding of the manner in which coordination geometry and substituent effects influence reaction selectivity. Emphasis was placed on elucidation of the intermediates involved in oxygenate reactions on the clean Pd(111) surface, and the influence of adsorbed oxygen upon the reactivity of these species. The implications of this study for the synthesis of oxygenated hydrocarbons from CO and H;The reaction selectivity for oxygenates adsorbed on Pd(111) was found to depend upon the coordination geometry. ;The presence of adsorbed oxygen altered the chemistry of oxygenates on Pd(111) in a number of ways. Electronic factors resulting from the presence of the electronegative oxygen adlayer favored coordination of aldehydes and ketones in the