液相空气氧化法制备氟代苯甲酸工艺研究

从氟代甲苯出发,以醋酸为溶剂,采用液相空气氧化法,在钴锰盐和1,1,2,2-四溴乙烷催化体系存在下,合成了氟代苯甲酸,采用升华方法进行精制。探讨了反应压力、催化剂配比及用量、溶剂比及溶剂浓度对氧化反应的影响,当反应压力为0.8～1.0 MPa、反应温度160～220℃、溶剂比4:1,钴锰催化剂质量比为2:1时,反应转化率接近100％;在真空度98 kPa下升华,总质量收率大于97％。

PREPARATION OF FLUOROBENZOIC ACID BY LIQUID PHASE AIR OXIDATION

Fluorobenzoic acids were prepared from fluorotoluenes through liquid phase air oxidation with acetic acid as solvent and Co~(2+)-Mn~(2+)-1, 1,2,2-tetrabromoethane as catalyst. The raw product was refined by sublimation. The effects of reaction pressure, catalyst and solvent were studied. The optimal conditions for this reaction were found as follows, reaction pressure 0.8-1.0 MPa, reaction temperature 160 - 220 ~C, weight ratio of solvent to fluorotoluene 4:1, mass ratio of Co~(2+) to Mn~(2+) 2:1. convertion of fluorotoluene is close to 100%. The total yield of refined product is 97% by weight.