Kinetic Study and Degradation Mechanism of Landrin in Aqueous Media

Abstract

The alkaline hydrolysis of landrin (2,3,5-trimethylphenyl-N-methylcarbamate) into 2,3,5-trimethylphenol was examined for various buffers and sodium hydroxide solutions ranging from pH 11.8 to 13.6. This work was carried out by reversed phase liquid chromatography and UV spectrophotometry. The positive activation entropy A Δ S#= +38.40 J mol −1 K −1 and the absence of general basic catalysis indicated an ElcB hydrolytic mechanism involving the formation of methyl isocyanate. This result was confirmed by the finding that landrin fits well into Brönsted and Hammett plots, obtained for a series of substituted N- methylcarbamates whose decomposition in aqueous media was established to follow an El cB mechanism.