T. Nguyen, J. Lavalley, J. Saussey
Feb 1, 1980
Citations
0
Influential Citations
11
Citations
Journal
Journal of Catalysis
Abstract
Infrared and Raman spectra from 3-phenyl-1-propyne (C6H5CH2CCH) and 1-phenyl-1-propyne (C6H5CCCH3) adsorbed on zinc oxide are reported. Isomerization between these adsorbates occurs via the formation of phenylallene, the third isomeric compound (C6H5CHCCH2). Both adsorbates have a common behavior over zinc oxide in that each gives rise to two types of dissociative chemisorption to yield acetylide species and propargyllic species; the former results from dissociation of the acetylenic hydrogen and the latter from removal of a proton attached to a carbon atom in an α-position to the triple bond. The propargyllic species are considered to be intermediates in the isomerization reactions, and their two possible structures C6H5CHCCH]− and C6H5cCCH2]− are characterized by intense infrared absorptions identically positioned at 1862 cm−1 which are assignable to the ν(CC) modes. The acetylide species C6H5CH2CC…Zn(surface) are characterized by the ν(CC) bands in the region 2080 to 2110 cm−1 in both infrared and Raman spectra. Infrared spectra from C6H5CD2CCD adsorbed on ZnO pretreated with D2O were also recorded to help to assign the infrared bands of propargyllic species from adsorbed non-deuterated compounds. They provide evidence for the two types of propargyllic species [C6H5CDCCD]− and [C6H5CCCD2]− in the form of absorption bands at 1830 and and 1857 cm−1, respectively.