微通道反应器在硝化反应中的应用

发布时间：2018-12-08 14:14

【摘要】：硝化反应在有机化合物的合成反应中占有重要地位,但是该反应却存在很多问题,如安全生产问题,区域选择性问题等,为此本文将微通道反应器引入到硝化反应中,旨在利用微反应器的独特优势达到硝化反应的安全生产,同时提高目标产物的选择性。本文研究了脂肪醇和简单芳烃的硝化,主要以异辛醇和邻二甲苯为硝化对象,将微通道反应器应用到硝酸酯和硝基芳烃化合物的合成反应中。(1)以硝硫混酸作硝化剂,通过考察反应温度、硝硫混酸的配比、硝酸浓度、异辛醇流速、硝酸与异辛醇的摩尔比以及惰性溶剂的使用对异辛醇硝化反应的影响,得到硝酸异辛酯在微通道反应器内合成的最佳条件。实验结果表明,在常温下,以n(HNO3):n(H2SO4)=1:2.5,硝酸浓度为55%,硝酸与异辛醇的摩尔比为1.4：1,此时硝酸异辛酯的纯度高达99.6%,收率也达到了99.5%。论述了微通道反应器内硝硫混酸硝化合成硝酸酯的反应机理。(2)对比HNO3、HNO3-H2SO4以及N205对邻二甲苯的硝化,我们最终选择使用绿色硝化剂五氧化二氮。以邻二甲苯为研究对象,系统研究了微通道反应器内反应温度、反应停留时间、五氧化二氮的用量以及不同溶剂的选择等因素对反应的影响,从邻二甲苯转化率、4-硝基邻二甲苯选择性两个方面出发,得到最佳反应条件。实验结果表明,选择乙腈作溶剂,在30℃下反应29.6s,当五氧化二氮摩尔量是邻二甲苯的1.1倍时,反应转化率达到87.6%,4-硝基邻二甲苯的选择性高达57.3%。(3)将微通道反应器应用到其他脂肪醇和简单芳烃的硝化反应中,与常规反应器相比,发现无论是转化率,还是选择性,都得到了明显的提高。
[Abstract]:Nitrification plays an important role in the synthesis of organic compounds, but there are many problems in the reaction, such as safety in production, regional selectivity and so on. The aim is to make use of the unique advantages of microreactors to achieve the safety of nitrification and to improve the selectivity of the target products. The nitration of fatty alcohol and simple aromatics was studied in this paper. The nitration of iso-octanol and o-xylene was studied. The microchannel reactor was applied to the synthesis of nitrates and nitroaromatic compounds. The effects of reaction temperature, the ratio of nitrate-sulfur mixed acid, the concentration of nitric acid, the flow rate of isooctanol, the molar ratio of nitric acid to isooctanol and the use of inert solvent on the nitration of isooctanol were investigated. The optimum conditions for synthesis of isooctyl nitrate in microchannel reactor were obtained. The experimental results show that at normal temperature, n (HNO3): n (H2SO4) = 1: 2.5, the concentration of nitric acid is 55 and the molar ratio of nitric acid to isooctanol is 1.4: 1. The purity of isooctyl nitrate is 99.6%. The yield was 99.5%. The reaction mechanism of nitration of nitrate-sulfuric acid to nitrate ester in microchannel reactor was discussed. (2) compared with the nitration of HNO3,HNO3-H2SO4 and N205 for o-xylene, we finally chose to use green nitrifying agent nitrogen pentoxide. The effects of reaction temperature, residence time, amount of nitrogen pentoxide and different solvents on the reaction of o-xylene in microchannel reactor were systematically studied. The optimum reaction conditions were obtained from the selectivity of 4-nitro-o-xylene. The experimental results show that when acetonitrile is used as solvent and reaction temperature is 30 鈩，

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