Adsorption and reaction of benzaldehyde on porous glass

COLL 469

Shoshanna R. Coon, Steven M. Badger II, and Alexander B. Nepomnyashchii. Department of Chemistry, University of Northern Iowa, Cedar Falls, IA 50614-0423
The surface chemistry of benzaldehyde on porous borosilicate glass was studied by transmission FTIR and by TPD. The average pore diameter of the glass was measured by AFM to be approximately 40 nm. After benzaldehyde was adsorbed at 50 K, temperature dependent FTIR showed disappearance of the C=O stretches beginning at 205 K and reaching maximum loss at 325 K. Carbon monoxide desorbed at 315 K in the TPD of adsorbed benzaldehyde, compared to 260 K for directly adsorbed CO, indicating that decomposition to CO and benzene occurs at approximately 315 K. However, no masses larger than 44 were desorbed at temperatures up to 500 K. The decomposition mechanism and the fate of the benzene decomposition product will be discussed.