无水硝酸的制备方法与应用进展

Progress of preparation and application of anhydrous nitric acid

无水硝酸是目前应用较为广泛的硝化试剂之一,但存在不稳定、难保存等缺点,导致其制备和使用受限。本文按二氯甲烷萃取法、电化学合成法、低温真空蒸馏法、脱水制备法和气相反应法对无水硝酸的制备方法进行了介绍,并比较各方法的优缺点及适用范围。同时简述了无水硝酸参与的不同硝化体系,包括单一无水硝酸体系、无水硝酸-硫酸体系、无水硝酸-乙酸酐体系、无水硝酸-固体酸体系和无水硝酸-N2O5体系,指出了各体系的性质、优缺点及主要应用,分析表明无水硝酸有望通过进一步工艺优化实现工业生产,并能与其他试剂形成性能更优异、更加环境友好的硝化体系,使其作为硝化剂在有机合成反应中发挥重要作用。

Anhydrous nitric acid is one of the widely used nitrate reagents. But it is unstable and difficult to store,which limits its preparation and application. The preparation methods of anhydrous nitric acid are summarized in this paper including extraction with dichloromethane,electrochemical synthesis,the low temperature vacuum distillation,dehydration and gas phase reaction. In addition,the advantages,disadvantages and the applicable scope of each method are compared. At the same time,this paper introduces different nitration systems with anhydrous nitric acid involved,including single anhydrous nitric acid system,anhydrous nitric acid-sulfuric acid system,anhydrous nitric acid-acetic anhydride system,anhydrous nitric acid-solid acid system and anhydrous nitric acid-N_2O_5 system,and points out the properties,advantages and disadvantages of each system as well as the main applications. The analysis shows that industrial production of anhydrous nitric acid is expected to be realized through further process optimization. The combination of anhydrous nitric acid with other reagents can form more excellent-performance, more environmentally friendly nitration systems, which will make anhydrous nitric acid continue to serve as an important nitrating agent and play a significant role in organic synthetic reactions.