Methyl esters of benzoic and mesitoic acid have been prepared with high yields (>98 wt%) from the corresponding carboxylic acids + methanol in aprotic solvents over samples of H2SO4/SiO2 at 60 C. The results show a high catalytic efficiency of the solids but also suggest an acid strength comparable to that observed in concentrated aqueous H2SO4 (range >90 wt%) when the acid requirements for the esterification of analogous compounds in aqueous acid solutions are taken into account. Indeed, different reacting species, i.e., ArC(OH)+2 from benzoic acid and 2,4,6-triMe-ArC=O+ from mesitoic acid are involved in the esterification, but the mesitoyl cation can be formed and esterified in the acidity ranges between 92 and 98 wt% H2SO4.
On the acidity of liquid and solid acid catalysts. Part 3. Esterification of benzoic and mesitoic acids / N.C. Marziano, C. Tortato, L. Ronchin, C.L. Bianchi. - In: CATALYSIS LETTERS. - ISSN 1011-372X. - 64:1(2000), pp. 15-22.
On the acidity of liquid and solid acid catalysts. Part 3. Esterification of benzoic and mesitoic acids
C.L. BianchiUltimo
2000
Abstract
Methyl esters of benzoic and mesitoic acid have been prepared with high yields (>98 wt%) from the corresponding carboxylic acids + methanol in aprotic solvents over samples of H2SO4/SiO2 at 60 C. The results show a high catalytic efficiency of the solids but also suggest an acid strength comparable to that observed in concentrated aqueous H2SO4 (range >90 wt%) when the acid requirements for the esterification of analogous compounds in aqueous acid solutions are taken into account. Indeed, different reacting species, i.e., ArC(OH)+2 from benzoic acid and 2,4,6-triMe-ArC=O+ from mesitoic acid are involved in the esterification, but the mesitoyl cation can be formed and esterified in the acidity ranges between 92 and 98 wt% H2SO4.
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