Reactivity of Anisoles on Clay and Pillared Clay Surfaces

Kathleen A. Carrado, Ryoichi Hayatsu, Robert E. Botto and Randall E. Winans
Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439

Abstract: Pillared bentonites were found to be efficient catalysts for the O-methyl bond cleavage of anisoles (e.g., m-methylanisole, guaiacol, and creosol) under very mild, static conditions (150°C, a few hours, inert atmosphere). The O-methyl bond cleavage led to phenolic products. Gas chromatographymass spectrometry and solid-state 13C nuclear magnetic resonance (NMR) techniques used to probe 13C-labeled anisoles revealed that dealkylation and transalkylation reactions occurred to a large extent, and that conversion was efficient at >95% after two days. Ortho- and para-isomers were observed exclusively, without any evidence of meta-substitution. Volatile products were determined by mass spectrometry to be 13CH3OH and (13CH3)2O. Magic-angle spinning 13C NMR experiments showed that the molecules were fairly mobile in the clay micropores prior to catalysis. After catalysis, cross-polarization NMR showed that molecular motion had decreased markedly. Ultraviolet-visible spectroscopy of the colored complexes suggested some quinone formation. The trend of clay reactivity was found to be: pillared bentonite ≫ acid-washed montmorillonite > untreated bentonite > pillared fluorhectorite ≃ untreated fluorhectorite.

Key Words: Anisoles • Bentonite • Catalysis • Fluorhectorite • Montmorillonite • Nuclear magnetic resonance • Pillared clay • Quinones

Clays and Clay Minerals; June 1990 v. 38; no. 3; p. 250-256; DOI: 10.1346/CCMN.1990.0380303
© 1990, The Clay Minerals Society
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