Verfahren zur Herstellung von p-Hydroxybenzoesäure

p-Hydroxy benzoic acid is prepared by reacting potassium phenolate, in the form of granules or briquettes having a maximum diameter or side length of 30 mms., with a mixture of CO2 and an inert gas at 100-210 DEG C. and up to 6 atmospheres pressure, the inert gas being present in an amount sufficient for removing the exothermic heat of reaction and the phenol produced, the phenol being condensed out and the CO2 replenished before the gas mixture is returned to the reactor. The inert gas is preferably nitrogen. The inert gas may be introduced into the reactor first and the partial pressure of CO2 then increased by stages.