化工学报 ›› 2020, Vol. 71 ›› Issue (3): 1045-1052.DOI: 10.11949/0438-1157.20190952

• 催化、动力学与反应器 • 上一篇    下一篇

超重力强化O3/H2O2氧化甲苯合成苯甲酸的研究

高文强1,2,焦纬洲1(),刘有智1   

  1. 1.中北大学超重力化工过程山西省重点实验室,山西 太原 030051
    2.吕梁学院化学化工系,山西 吕梁 033000
  • 收稿日期:2019-08-21 修回日期:2019-10-22 出版日期:2020-03-05 发布日期:2020-03-05
  • 通讯作者: 焦纬洲
  • 基金资助:
    国家自然科学基金项目(U186210097);山西省三晋学者支持计划项目(201707);山西省优秀人才科技创新项目(201705D211011);山西省研究生教育创新项目(2019BY/06)

Oxidation of toluene to benzoic acid by O3/H2O2 process enhanced usinghigh-gravity technology

Wenqiang GAO1,2,Weizhou JIAO1(),Youzhi LIU1   

  1. 1.Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan 030051, Shanxi, China
    2.Department of Chemistry and Chemical Engineering, Luliang University, Luliang 033000, Shanxi, China
  • Received:2019-08-21 Revised:2019-10-22 Online:2020-03-05 Published:2020-03-05
  • Contact: Weizhou JIAO

摘要:

提出一种超重力环境下甲苯合成苯甲酸的新方法,对比不同臭氧化工艺合成苯甲酸的收率,研究了反应溶剂、臭氧气相浓度、过氧化氢与甲苯的摩尔比、超重力因子、液体流量对苯甲酸收率的影响规律。研究结果表明:RPB (rotating packed bed)-O3/H2O2较其他工艺具有更高的反应性能;得到优化的工艺条件是反应溶剂为乙腈、臭氧气相浓度为80 mg·L-1、过氧化氢与甲苯的摩尔比为0.15、超重力因子为40、液体流量为120 L·h-1,在优化的工艺条件下得到苯甲酸收率为45%。通过电子顺磁共振仪 (EPR)对反应过程中产生的活性自由基进行表征,结果表明,O3/H2O2体系中存在·OH。另外,用气相色谱-质谱联用仪(GC-MS)分析了中间产物,结果表明反应过程中生成的中间产物包括苯甲醇和苯甲醛。基于ERP实验和GC-MS表征结果,探索臭氧/双氧水氧化甲苯合成苯甲酸可能的反应历程。

关键词: 甲苯, 苯甲酸, 旋转填料床, 臭氧, 双氧水, 羟基自由基

Abstract:

The synthesis of benzoic acid using ozone combined with hydrogen peroxide in a rotating packed bed (RPB) was proposed in this study. Firstly, the process (RPB-O3/H2O2) was compared with other ozonation processes, such as BR (bubbling reactor)-O3/H2O2,RPB-O3,BR-O3, and RPB-O3/H2O2 exhibited higher oxidation property for the synthesis of benzoic acid. Secondly, effects of different operating conditions including solvents, ozone gas concentration, molar ratio of hydrogen peroxide to toluene, high gravity factor, liquid flow rate, solvents and reaction time were investigated. The results revealed that the optimal operation conditions were solvent of acetonitrile, the ozone gas concentration of 80 mg·L-1, molar ratio of hydrogen peroxide to toluene 0.15, high gravity factor of 40, liquid ?ow rate of 120 L·h-1. Under the optimal conditions, the benzoic acid is obtained in 45% yield. The active radical generated in the reaction process was characterized by electron paramagnetic resonance (EPR), and ·OH was only found. Besides, the main intermediates of benzyl alcohol and benzaldehyde were identified by gas chromatography-mass spectrometry (GC-MS). Based on the results of ERP experiment and GC-MS characterization, the possible reaction process of benzoic acid synthesis by oxidation of toluene with ozone / hydrogen peroxide was explored.

Key words: toluene, benzoic acid, rotating packed bed, ozone, hydrogen peroxide, hydroxyl radical

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