Solvent-assisted Carboxylation of Alkali Metal Phenoxide with Carbon Dioxide

Abstract

The carboxylation of alkali metal phenoxide with carbon dioxide gives not only ortho-but also para-hydroxybenzoic acids at room temperature, unlike the well-known Kolbe±Schmitt reaction.

Voltammetric study of the reaction of the 2-cyanophenoxide anion with carbon dioxide in dimethylformamide

“…Similarly, it has been reported that the IR spectrum of a sodium phenoxide-carbon dioxide complex displays the carbonyl band at 1684 cm À1 . [30][31][32] The results suggest the rapid complexation of the cyanophenoxide anion with carbon dioxide in DMF, consistent with the findings of Kosugi et al [6][7][8] Again, this supports the electrochemical reduction mechanism given in Scheme 1 where the reaction/complexation of 2-cyanophenoxide with carbon dioxide occurs. The UV/visible spectroscopic analysis and the voltammetric results demonstrate the reversibility upon carbon dioxide removal.…”

“…120 1C. [6][7][8][9][10][11][12] Kosugi et al have recently found that on the introduction of carbon dioxide at room temperature to potassium phenoxide the direct carboxylation is competitive with the formation of the alkali metal phenoxide complex, 7 carbon dioxide at atmospheric pressure yielding predominantly the complex. In the mechanism for the electrochemical reduction of 2-cyanophenol, the parent molecule is reduced to the radical anion species, which is then rapidly protonated by the parent molecule to form a protonated radical species and 2cyanophenoxide.…”

“…The formation of a complex between the alkali metal phenoxide and carbon dioxide complex is the believed intermediate of the reaction. [6][7][8][9][10][11][12] A p-complex type structure is assumed for the alkali metal phenoxide-carbon dioxide complex, with the oxygen atom of carbon dioxide forming a weak bond with the potassium cation. 13,14 Mori and Sataki have investigated the uptake of carbon dioxide by potassium phenoxide in DMF at various carbon dioxide pressures and found that potassium phenoxide binds strongly with carbon dioxide and considerable amounts of carbon dioxide are absorbed even at low carbon dioxide pressures.…”

Synthesis of Diphenyl Carbonate from Phenol and Carbon Dioxide in the Presence of Carbon Tetrachloride and Zinc Chloride

“…In the first stage of the reaction of phenol with CO 2 , salicylic acid-like compounds 1, which would change into DPC and PS, p-hydroxybenzoic acid-like compounds 2 and metal phenoxide-CO 2 complex 3 should be formed, as illustrated in Scheme 1 [40]. The latter 3 should not transform into 1 (or 2) at low temperatures [41], but, at high temperatures, 3 may thermally decompose back to the phenoxide [42] and it can have a chance of changing into the desired product of DPC and PS. This may explain that the selectivity to DPC increased with temperature as observed at \100°C (Fig.…”