【作者】 张静；

【导师】 王莅；

【作者基本信息】 天津大学 ， 化学工艺， 2006， 硕士

【摘要】 新型绿色硝化剂N₂O₅较传统硝化剂具有反应热效应小,温度容易控制;产物分离简单;对多官能团的物质选择性高,可用于对酸敏物质的硝化等优点,逐渐成为人们关注的热点。本文采用拉曼光谱法、核磁共振光谱法和化学滴定法建立了三种N₂O₄-N₂O₅-HNO₃体系的分析方法;采用浊点法测定了该体系液液和固液平衡数据;在间歇反应器中研究了N₂O₅与环氧丙烷硝化反应。低温拉曼光谱分析结果表明,N₂O₅浓度不超过21%时,浓度与NO²⁺衍射峰面积呈近似线性关系,因此,该方法可用于N₂O₄电氧化制备N₂O₅的过程监控。氧化还原和酸度两步滴定与氧化还原滴定结合核磁共振光谱法的分析结果表明,两种方法的分析结果吻合良好,精确度良好,两种方法都可用于N₂O₄-N₂O₅-HNO₃体系各组分的全浓度分析。在两步滴定过程中,适宜的分析条件是采用硫酸铈为氧化剂;纯水作为溶剂;采用安瓿球取样。在258.2～281.2 K温度范围内,测定了N₂O₄-N₂O₅-HNO₃三元体系的液液和固液平衡数据,得到了液液和固液平衡的临界点及N₂O₄和HNO₃中N₂O₅溶解度等数据。采用拉曼光谱仪、核磁共振光谱仪和气相色谱-质谱联用仪对N₂O₅和环氧丙烷硝化的主副产物进行了结构鉴定。结果表明,N₂O₅和环氧丙烷硝化的主产物是1,2-丙二醇二硝酸酯,副产物是1,2-丙二醇单硝酸酯。同时考察了反应溶剂、反应温度、N₂O₅中N₂O₄和HNO₃杂质对1,2-丙二醇二硝酸酯收率和纯度的影响,结果表明,适宜的溶剂是CHCl3;适宜的反应温度为10～15℃;在适宜条件下,1,2-丙二醇二硝酸酯的收率和纯度可分别达到99.01%和95.89%;N₂O₄和HNO₃对产物的收率和纯度均有不利影响,但当N₂O₅中N₂O₄含量小于1.00%,HNO₃含量小于5.53%时,对产物收率和纯度的影响不大。更多还原

【Abstract】 Advantages of new green nitrating agent of dinitrogen pentoxide in comparison to conventional nitrating agents are: ease of temperature control, simple isolation of the product, high selectivity in position of attack with multifuctional substrates, fasibility towards the reaction in acidic medium to offer strong nitrating system. So it receives more and more concerns.In this study, the N2O4-N2O5-HNO3 system was analyzed by the methods of Raman spectrum, nuclear magnetic resonance spectrum (NMR) and chemical titration. Cloud-point method was used to obtain the data of Liquid-Liquid and Solid-Liquid equilibrium. The nitration reaction of propylene oxide with dinitrogen pentoxide was conducted in a batch reactor.The results of low-temperature Raman spectrum indicated that the integrated intensity of the nitronium cation (NO2+) at 1400cm-1 with the concentrations of pentoxide dinitrogen was approximately linear. Thus this method could be applied to monitor the process of producing dinitrogen pentoxide by electrochemical oxidation of dinitrogen tetroxide in nitric acid.The results from the two-step titration method of redox titration combined with acidity titration were well consistent with that from the method of redox titration combined with NMR. Both analytic methods had high accuracy and were good to analyze the N2O4-N2O5-HNO3 system. In the two-step titration, optimum conditions were cerium sulfate as oxidant, sampling using ampoule ball and distilled water as solvent.Liquid-Liquid and Solid-Liquid equilibrium data for the N2O4-N2O5-HNO3 system was obtained at 258.2K ~281.2 K. The critical points and the solubility of dinitrogen pentoxide in dinitrogen tetroxide and nitric acid, respectively, were determined. The structures of the reaction products in the nitration of propylene oxide were identified by Raman, NMR and GC-MS. The results indicated that 1,2-propanediol dinitrate was the main product in the nitration reaction, 1,2-propanediol nitrate the major byproduct. The effect of reagents, reaction temperature, dinitrogen tetroxide and nitric acid on the yield and purity of 1,2-propanediol dinitrate were also investigated. The results indicated that CHCl3 was optimum reagent and the reaction temperature was better controlled at 10~15℃. Dinitrogen tetraoxide and nitric acidhad a detrimental effect on the yield and purity of 1,2-propanediol dinitrate. When the concentrations of dinitrogen tetroxide and nitric acid were below 1.00% and 5.53% respectively, these detrimental effects could be neglected. Under the optimum conditions, the yields and the purity of 1,2-propanediol dinitrate were 99.01% and 95.89%, respectively.更多还原