REACTIVITY OF ANISOLES ON CLAY AND PILLARED CLAY SURFACES

Pillared bentonites were found to be efficient catalysts for the O-methyl bond cleavage of anisoles under very mild, static conditions. The O-methyl bond cleavage led to phenolic products. Gas chromatography-mass spectrometry and nuclear magnetic resonance (NMR) techniques 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. 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. -from Authors