Acid-catalysed carboxymethylation, methylation and dehydration of alcohols and phenols with dimethyl carbonate under mild conditions

Abstract

Dimethyl carbonate (DMC) chemistry has been extended to include acid-catalysed reactions of different aliphatic alcohols and phenols. For the first time, p-toluenesulfonic acid (PTSA), H₂SO₄, AlCl₃ and FeCl₃ have been shown to aid carboxymethylation for primary aliphatic alcohols at catalytic loadings with quantitative conversion and selectivity. For carboxymethylation of secondary alcohols, stoichiometric PTSA and catalytic AlCl₃ both gave quantitative conversion and selectivity. Stoichiometric FeCl₃ and H₂SO₄ promoted dehydration of linear aliphatic alcohols. Additionally FeCl₃ catalysed methylation of cyclohexanol, whilst AlCl₃ resulted in methylation of phenolic compounds. This research expands the range of potential application for DMC in green chemistry.