Montmorillonite clay catalysis. Part 10. K-10 and KSF-catalysed acylation of alcohols, phenols, thiols and amines: scope and limitation

Montmorillonite K-10 and KSF are highly efficient catalysts for the acetylation of a variety of alcohols, thiols, phenols and amines with acetic anhydride. Amino groups can be selectively acetylated in the presence of hydroxy groups, while the hydroxy groups can be preferentially acetylated in the presence of thiol groups. No selectivity is observed between primary and secondary hydroxy groups in the presence of K-10 and KSF. The catalysts are found not to be efficient for acetylation of tertiary alcohols. This method is simple and convenient with minimum environmental impact. The catalysts are also effective for the acylation of alcohols; thiols, phenols and amines with acetyl chloride and benzoyl chloride. Cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic: anhydride and p-toluene sulfonyl chloride show less reactivity than acetic anhydride and acyl chlorides.