| 摘要 |
PURPOSE:To obtain the titled compound economically in a yield equal to that in the conventional method, by reacting resorcinol with a small amount of an inexpensive alkali metal carbonate in an aqueous solution in the presence of CO2 gas, and reutilizing a gas generated in the acid coagulation treatment. CONSTITUTION:Resorcinol is reacted with an alkali metal carbonate in an aqueous solution in the presence of CO2 gas under heating at 80-100 deg.C, and the reaction solution after the completion of the reaction is cooled to 0-50 deg.C to deposit the alkali and separate the alkali from the aqueous layer. The separated alkali is then used together with the above-mentioned alkali metal carbonate. The aqueous layer separated in an acid solution, e.g. sulfuric acid, is then continuously added thereto to carry out the acid coagulation treatment, and deposited crystals of beta-resorcylic acid are separated. CO2 gas generated in the step is reused as part or all of the CO2 gas to be used in the thermal reaction step, and the rate of addition of the separated aqueous layer to the acid solution is preferably adjusted to give the desired feed rate. USE:A raw material for ultraviolet light absorbers.
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