Indirect Electrosynthesis of Benzaldehyde from Toluene Using a Mediate Couple V5+/V4+ PartⅠ:Oxidation of Toluene into Benzaldehyde by V5+ in Acidic Solutions Yi Qingfeng, Liu Xiaoping, Shi Hongwen, Song H e fu, 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 (PDF全文下载c02056)