Preparation of 2,6-dihydoxybenzoic acid by direct carboxylation of resorcinol with CO2 in solvent under low pressure was studied. The optimum reaction parameters were determined as follows: reaction pressure of 0.4-0.5MPa, reaction temperature of 140℃, reaction time of 6-7 hours, molar ratio of resorcinol to potassium hydroxide of 1:2.05 and toluene as solvent. Under the optimized conditions, after washing, acidification, decolonization and recrystallization, the yield of 2,6-dihydroxybenzoic acid could be up to 70% with the purity of more than 99 % (HPLC).%研究了间苯二酚低压溶剂羧化法合成2,6-二羟基苯甲酸.适宜的反应条件为:反应压力0.4MPa.～0.5MPa反应温度140℃,反应时间6h～7h,n(同苯二酚)/n (氢氧化钾)=1/2.05,溶剂为甲苯.在适宜的条件下,产物经洗涤、酸化、脱色和重结晶等后处理工序,产品收率达70％,纯度大于99％ (HPLC).
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