【摘要】 为优化2,6-二氟苯甲酸(DFBA)的合成工艺,以2,6-二氯苯腈(DCBN)和氟化钾为原料,N,N-二甲基酰胺(DMF)为溶剂,在聚醚类催化剂A的催化下氟代合成中间体2,6-二氟苯腈,然后中间体在碱性条件下水解制得(DFBA)。试验结果表明,合成DFBN的最佳条件为:DCBN在DMF中的质量浓度为0.38g/mL,KF的量为DCBN的量的2.3～2.4倍,反应时间10h,最高收率93.5%;合成DFBA时,以质量分数为20%的NaOH为介质,反应时间9h,收率≥92%。收率93.5%,纯度99.7%。该工艺收率高、三废排放少,可节省成本,有望工业推广。更多还原

【Abstract】 In order to optimize synthesis process of 2,6-difluorobenzoic acid (DFBA), 2,6-difluorobenzonitrile is fluorization synthesized from 2,6-dichlorobenzonitrile (DCBN) and potassium fluoride with N,N-dimethylformamide (DMF) as a solvent over the polyether catalyst A, and then the intermediate 2,6-difluorobenzonitrile is hydrolyzed under the alkali conditions to get DFBA.Experiment results show that the best conditions for DFBN are as follows: quality concentration of DCBN in DMF 0.38 g/mL, KF amount 2.3-2.4 tims over DCBN, reaction time 10 h, the highest yield 93.5%; in the synthesis of DFBA, 20% by quality fraction NaOH is used as a medium with reaction time 9 h and yield≥92%. Yield is 93.5%, purity is 99.7%. Yield in this technology is high with little discharge of ″three wastes″, which can reduce the cost and be adopted in industry.更多还原