Abstract
Carboxylation reactions of sodium phenoxide under carbon dioxide pressure in a liquid state were studied. The effects of the physical and chemical properties of solvents on the yield of hydroxy carboxylic acids and the ratio of p-isomer/o-isomer were clarified.
On the whole, the yield of the desired product attained by this treatment was poorer than that by the gas-solid state reaction, though the p-isomer/o-isomer ratio remained almost unchanged. However, when water-miscible aprotic polar solvents, such as DMF, DMA, NMP, and HMPA, were used at a temperature below 180°C, the p-isomer/o-isomer ratio was markedly increased. Such effects were not noted with other types of solvents.
