摘要
以七水硫酸钴、浓硫酸、硫酸铵为原料,电氧化合成Co^3+,用Co^3+氧化对甲砜基甲苯合成对甲砜基苯甲酸。考察了电极材料、电解温度、电流密度、硫酸浓度以及电解液循环套用对电极反应和硫酸浓度、Co^3+与对甲砜基甲苯物质的量比对氧化反应的影响。结果表明,在选用阳极二氧化铅、阴极铅为电极板,陶瓷膜作为阳离子交换膜,电解液浓度为c(Co^2+)=0.5 mol/L、c (硫酸)=4.0 mol/L、c (硫酸铵)=0.15 mol/L,电极间距(d)为2 cm、电流密度(J)为350 A/m2、电解温度(T)为10℃时,电解液Co^2+转化率可达80%,电解氧化电流效率达67.5%。在进行对甲砜基甲苯的氧化时,控制电解液浓度为c(Co^3+)=0.4 mol/L、c(硫酸)=4.0 mol/L、c(硫酸铵)=0.15 mol/L,n(Co^3+)∶n(对甲砜基甲苯)=6∶1,使得反应温度为30℃,反应时间为30 min,对甲砜基苯甲酸的收率可达97.8%,精制后纯度在98.5%以上。
Co^3+ was synthesized by electrooxidation using cobalt sulfate heptahydrate, concentrated sulfuric acid and ammonium sulfate as raw materials and used for the oxidation of 1-methyl-4-(methylsulfonyl)benzene to p-methylsulfonylbenzoic acid. The influences of electrode materials, electrolysis temperature, current density, sulfuric acid concentration and electrolyte circulation on the electrode reaction were investigated. Moreover, the influences of sulfuric acid concentration, reaction temperature, reaction time, electrolyte concentration, ammonium sulfate concentration and molar ratio of materials on the oxidation reaction were studied. The results showed that the electrolyzer was consisted of lead dioxide anode, cathode lead electrode plates and ceramic membrane as a cation exchange membrane with electrolyte concentration c(Co^2+)=0.5 mol/L, c(sulfuric acid)=4.0 mol/L, c(ammonium sulfate)= 0.15 mol/L. When electrode spacing d=2 cm, current density J=350 A/m2 and electrolysis temperature T=10 ℃, the electrolyte Co^2+ conversion could reach 80% and the electrolytic oxidation current efficiency was 67.5%. When the conditions was controlled at concentration of electrolyte c(Co^3+)=0.4 mol/L, c(sulfuric acid)= 4.0 mol/L, c(ammonium sulfate)=0.15 mol/L, n(Co^3+)︰n〔1-methyl-4-(methylsulfonyl)benzene〕= 6∶1, reaction temperature 30 ℃ and reaction time 30 min, the yield of p-methylsulfonylbenzoic acid could reach 97.8% and its purity was over 98.5% after refining.
作者
冯柏成
初晓东
董静静
金岩
FENG Bai-cheng;CHU Xiao-dong;DONG Jing-jing;JIN Yan(College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042,Shandong,China)
出处
《精细化工》
EI
CAS
CSCD
北大核心
2019年第11期2330-2335,共6页
Fine Chemicals
关键词
电氧化
对甲砜基苯甲酸
绿色化工
精细化工中间体
electrooxidation
p-methylsulfonylbenzoic acid
green chemical industry
fine chemical intermediates
