CHEMISORPTION OF BENZENE ON CU-MONTMORILLONITE AS CHARACTERIZED BY FTIR AND C-13 MAS NMR

Sorption of benzene onto Cu-montmorillonite was characterized by Fouri er transform infrared (FTIR) spectroscopy and C-13 magic angle spinnin g nuclear magnetic resonance (MAS NMR). Under anhydrous conditions, ch emisorption of benzene in the interlamellar region of Cu-montmorilloni te led to the formation of a dark red surface complex that exhibited a vibrational spectrum similar to that of doped poly-p-phenylene. When the benzene sorption reaction was carried out under high relative humi dity conditions, polymerization of benzene did not occur. The FTIR spe ctrum of the surface complex formed under wet conditions exhibited vib rational bands that could not be assigned to those of the parent benze ne molecule or to those of previously observed chemisorbed Type I or T ype II complexes. C-13 MAS NMR spectra of C-13-enriched benzene sorbed onto Cu-montmorillonite powder showed the presence of two groups of p eaks that could be assigned to aromatic and aliphatic carbon respectiv ely.