Yi Qingfeng, Liu Xiaoping, Shi Hongwen, Song Hefu, Zhao Honggang
(Chemical Engineering Department of Xiangtan Polytechnic University, Hunan Xiangtan 411201)

Abstract Toluene is oxidized into benzaldehyde by V⁵⁺ in acidic solutions. Effects of H₂SO₄ concentrations, molar ratios of V⁵⁺ to toluene, reaction temperature and time on the yield of benzaldehyde are studied and discussed. Results show that for lower H₂SO₄ concentrations where oxidation potentials of V⁵⁺ decrease, it will lead to low yields of benzaldehyde. However, when H₂SO₄ concentrations are more than 11mol·L, the yield of benzaldehyde decreases. Under the conditions that H₂SO₄ concentration is 11mol·L, molar ratio of V⁵⁺ to toluene is 1:11, reaction temperature is 80°C and reaction time is 180 min, the yield of benzaldehyde reaches to 71.32%. It is indicated from kinetic research of the reaction that apparent reaction order of oxidation of toluene by V⁵⁺ into benzaldehyde is 1.
Key words Toluene, Benzaldehyde, V⁵⁺/V⁴⁺, Electrosynthesis of organic compound

用V⁵⁺/V⁴⁺媒质电对实现苯甲醛的间接电合成研究
Ⅰ酸性溶液中用V⁵⁺氧化甲苯生成苯甲醛^*

易清风 刘小平 史红文 宋和付 赵红钢
(湘潭工学院化学工程系 湖南湘潭 411201)

摘要 研究了在硫酸溶液中，以V⁵⁺为氧化剂将甲苯氧化为苯甲醛。探讨了硫酸浓度、V⁵⁺与甲苯的摩尔比、反应温度以及反应时间等因素对苯甲醛产率的影响。结果表明，硫酸浓度较低时，苯甲醛产率也较低，这是因为溶液酸度较低时，V⁵⁺的氧化性较弱；但硫酸溶液浓度超过11mol·L时反应产率下降，可能与反应的副产物增加有关。在硫酸浓度为11mol·L、甲苯与V⁵⁺物质的量之比为11:1、反应温度80°C以及反应时间为180 min等条件下，苯甲醛产率可达71.32%。动力学研究表明, V⁵⁺氧化甲苯为苯甲醛的表观反应级数为1。
关键词 甲苯 苯甲醛 V⁵⁺/V⁴⁺ 有机电合成

易清风 男，39岁，博士，教授，从事电化学与热力学研究。
湖南省教育厅科研项目资助
2001-10-24收稿，2002-02-02修回

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