大学化学 >> 2020, Vol. 35 >> Issue (4): 103-111.doi: 10.3866/PKU.DXHX201912001

所属专题： 全国大学生化学实验创新设计竞赛

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苯甲醇和苯甲酸制备实验的改进与创新设计

全晓塞(), 门秀琴, 王军旗, 周颖, 姚俊   

  • 收稿日期:2019-12-02 录用日期:2019-12-16 发布日期:2020-02-17
  • 通讯作者: 全晓塞 E-mail:XsQUAN@nxu.edu.cn
  • 基金资助:
    宁夏回族自治区教育厅本科教育教学改革研究与实践项目(nxbjy-19);宁夏高等学校一流学科建设资助项目(NXYLXK2017A04)

Improvement and Innovative Design on Preparation of Benzyl Alcohol and Benzoic Acid

Xiaosai Quan(), Xiuqin Men, Junqi Wang, Ying Zhou, Jun Yao   

  • Received:2019-12-02 Accepted:2019-12-16 Published:2020-02-17
  • Contact: Xiaosai Quan E-mail:XsQUAN@nxu.edu.cn

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摘要：

以苯甲醛为原料，通过Cannizarro反应制备苯甲醇和苯甲酸是有机化学实验教学中的经典内容。鉴于现有实验方案已难满足日益提升的教学要求，对其进行了改进与创新设计：采用微波辐射法合成，引入正交设计优化条件；采用紫外分光光度法定量测定粗产品中苯甲醇的含量；采用柱层析法分离得到苯甲醇。改进结果表明：KOH溶液浓度50%（质量百分比），微波功率500 W时，反应15 min完成。光度法定量显示苯甲醇产率可达82.0%。萃取分离后的粗产品用50：1和15：1石油醚/乙酸乙酯（体积比）梯度洗脱，柱层析分离后可得苯甲醇纯品，水相酸化重结晶后得到苯甲酸。产物的相关测试与表征结果与文献吻合良好。与传统方案相比，新方案时间锐减99%，产率提高约15%，萃取剂更安全，产率测定快速准确，产物纯化方法优化。将之用于教学，可通过各要点功能的分别承载，综合实现研究性思维与方法的培养目标。

关键词: 微波辐射, 正交试验, 分光光度法, 改进与创新

Abstract:

The preparation of benzyl alcohol and benzoic acid from benzaldehyde by Cannizarro reaction was the common content of organic chemistry laboratory teaching. Nevertheless, due to its time consuming, low yield and inefficient isolating method, this experimental design was far from satisfactory in teaching. The following improvements have been made:Microwave radiation method was introduced, and the synthesis conditions was optimized by orthogonal test design. Under optimized conditions which was 50% KOH, microwave radiation at 500 W for 15 min, the reaction was completed. The yield of benzyl alcohol could reach 82.0%. Benzyl alcohol was isolated by column chromatography instead of distillation, to avoid the formation of distillation by-products. The yield of benzyl alcohol in crude products was determined quickly and accurately by spectrophotometry without separation. The comparison showed that the improved method could reduce the time by 99% and increase the yield by 15%. In addition, the extraction agent was more safe. The improvement was more responsive to the increasing requirements of laboratory training development.

Key words: Microwave radiation, Orthogonal test, Spectrophotometry, Improvement and innovation