五氧化二氮硝化机理研究

发布时间：2018-03-29 01:10

本文选题：五氧化二氮　切入点：机理　出处：《武汉科技大学》2016年硕士论文

【摘要】：采用五氧化二氮作为硝化剂的新工艺是当前具代表性的新型硝化技术。五氧化二氮/硝酸体系在含能材料方面应用广泛,如硝解3,7-二硝基-1,3,5,7-四氮杂双环[3,3,1]壬烷(DPT)制备1,3,5,7-四硝基-1,3,5,7-四氮杂环辛烷(HMX)。随着五氧化二氮电解制备的成熟化,五氧化二氮/硝酸体系有望将来在工业上得到大规模的应用,相关硝化机理的研究显得越来越重要。本文主要研究了五氧化二氮/硝酸体系硝解DPT制备HMX的机理,主要分两个方面进行研究:一是底物DPT的断键方式,二是五氧化二氮以什么形式进攻DPT。通过利用液相色谱-质谱联用仪来监测反应过程中产生的中间产物,推断出了DPT可能的断键路线,同时也得出,在低温和低酸度且体系的硝化能力不能过强的条件才有利于HMX的生成。通过几组实验直接和间接地确定了五氧化二氮在硝酸中是以硝酰阳离子的形式进攻DPT:五氧化二氮/硝酸硝化对氯硝基苯为一级反应,反应速率与共价五氧化二氮分子没有关系,排除了共价五氧化二氮分子硝化机理;五氧化二氮/硝酸硝化萘,没有1,3-二硝基萘和2,3-二硝基萘生成,排除了自由基硝化机理;五氧化二氮/硝酸拉曼光谱有硝酰阳离子的特征吸收峰,并且随着五氧化二氮浓度增加,硝酰阳离子特征峰面积增大,五氧化二氮/硝酸硝化对氯硝基苯的产物的量会随着硝酸铵的加入,而逐渐减少,当对氯硝基苯和对硝基甲苯同时加入体系中,会先硝化对硝基甲苯,然后再硝化对氯硝基苯,这几组实验都证明了硝酰阳离子硝化机理。根据五氧化二氮/硝酸体系硝解DPT制备HMX的机理的研究结果,提出了五氧化二氮/硝酸/有机溶剂体系。在已研究的四种有机溶剂中,同比例条件下,五氧化二氮/硝酸/乙酸酐体系符合硝化能力适中、低酸度条件,制备HMX的收率最好,其中当乙酸酐和硝酸体积比为2:3,时,五氧化二氮/硝酸/乙酸酐硝解DPT制备HMX的收率为87.9%。
[Abstract]:The new process of nitrification using nitrogen pentoxide as nitrifying agent is a representative new nitrification technology. Nitrogen pentoxide / nitric acid system is widely used in energetic materials. For example, the synthesis of HMXX by nitriolysis from 3HN 7- DPTs (3 DPTs). With the maturation of electrolysis of nitro pentoxide, the system of nitrogen pentoxide / nitric acid is expected to be applied on a large scale in the future, and the system is expected to be widely used in industry with the development of the electrolysis of nitro 2 pentabicylic acid (HMXX), and the synthesis of HMXX is expected to be carried out in a large scale in the future, and the results show that the HMXX system is suitable for the production of HMXX in the future. The study of nitrification mechanism is becoming more and more important. In this paper, the mechanism of nitration of DPT in nitrite / nitric acid system has been studied in two aspects: first, the bond breaking method of DPT substrate. The second is the form in which nitrogen pentoxide attacks. By using liquid chromatography-mass spectrometry to monitor the intermediate products produced in the reaction process, the possible bond breaking route of DPT is inferred, and the possible bond breaking route is also obtained. The formation of HMX was facilitated by low temperature and low acidity, and the nitrification ability of the system could not be too strong. It was determined directly and indirectly by several experiments that nitrogen pentoxide attacks HMX in nitric acid as nitroyl cationic acid: pentoxide. Nitration of p-chloronitrobenzene by nitration of diazo / nitric acid was a first-order reaction. The reaction rate was not related to the covalent dinitrogen pentoxide molecule, and the nitration mechanism of the covalent nitrogen pentoxide molecule was excluded, while nitration naphthalene pentoxide / nitration of naphthalene nitrate did not produce 1o 3-dinitronaphthalene and 2o 3-dinitronaphthalene, which excluded the mechanism of free radical nitration. The characteristic absorption peaks of nitrate cations were found in the Raman spectra of nitrogen pentoxide / nitric acid, and the area of the characteristic peaks increased with the increase of nitrogen pentoxide concentration. When p-chloronitrobenzene and p-nitrotoluene were added into the system, p-nitrotoluene and p-chloronitrobenzene were first nitrated and then nitration of p-chloronitrobenzene. These experiments have proved the nitration mechanism of nitrate cationic acid. According to the mechanism of nitration of DPT in nitration of nitrogen pentoxide / nitric acid system, In this paper, the nitrogen pentoxide / nitric acid / organic solvent system was proposed. In the four organic solvents studied, under the same proportion, the nitrification ability of the nitrogen pentoxide / nitric acid / acetic anhydride system was moderate, and the yield of HMX was the best under the condition of low acidity. When the volume ratio of acetic anhydride to nitric acid was 2: 3, the yield of HMX was 87.9% when the ratio of acetic anhydride to nitric acid was 2: 3, and the yield of HMX was 87.9% when the ratio of acetic anhydride to nitric acid was 2: 3.
【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ126.23

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