【作者】 刘周恩；

【导师】 章亚东；

【作者基本信息】 郑州大学 ， 化学工艺， 2006， 硕士

【摘要】 2，4-二硝基氯苯是一种重要的精细化工中间体，具有广泛的用途，其市场前景广阔；同时，其传统生产工艺存在污染环境、浪费能源等缺陷。为此，本课题采用连续绝热硝化法开展了由氯苯合成2，4-二硝基氯苯生产工艺的研究，具体工作如下：设计了连续绝热硝化反应装置——四釜串联硝化反应装置，并用水模拟实验及反应原料对该装置进行了调试和校正，使其达到了实验要求。采用正交实验探索了硝酸比（φ）、硫酸质量分数（S）、硝酸质量分数（N），反应物料体积流量（Q）等主要因素对反应的影响，影响顺序为：N>Q>φ>S。通过单因素法对各因素的影响性进行了深入的研究，得出了较佳的工艺条件，即：φ=2.22，S=0.680，N=0.220，W=0.100（W：混酸中水的质量分数），Q=16mL·min^-1[Qc=3.46mL·min^-1（Qc：氯苯的体积流量）]，t=40 min（t：反应停留时间）。在该工艺条件下，氯苯转化率可达100％，反应选择性为95.4％，以氯苯量计，产率为95.4％，粗产品中2，4-二硝基氯苯含量为96.39％；对粗产品的熔点和结晶点进行了测定，其熔点为49.8℃，结晶点为47.48℃；对合成实验的重复性和稳定性进行了验证，其产率均在95％以上，实验的稳定性和重复性较好。采用熔融结晶法对粗产品进行了结晶，优化出了较佳的结晶工艺条件，即：结晶降温速率在47～45℃区间内为3℃·（15min）^-1，在45～22℃区间内为4.5℃·（15min）^-1，结晶时间τc为140 min；发汗升温速率在22～43℃区间内为6℃·（15min）^-1，在43～46℃区间内为3℃·（15min）^-1，发汗时间为248 min，整个结晶实验时间为388 min。在该工艺条件下，结晶、提纯后的成品的2，4-二硝基氯苯含量可达99.10％，以粗产品的质量计，收率为91.91％；对结晶实验的重复性和稳定性进行了验证，实验的误差<0.03％，结晶实验的稳定性和重复性较好；对成品的熔点和结晶点进行了测定，熔点为50.9℃，结晶点为48.61℃，产品达到了国家规定的行业标准HG／T 2553-2003中的优级品的要求。对废酸的处理和再利用进行了研究，首先，采用氯苯萃取的方法来处理废酸中的硝酸和有机物，然后，采用蒸馏浓缩的方法以除去过量的水。处理后，废酸中的硝酸质量分数<0.010，有机物的质量分数<0.010，硫酸的质量分数约为0.920，水的质量分数约为0.06～0.07，废酸中的硫酸达到了重复使用的要求。使用由处理过的废酸中的硫酸配制的混酸进行反应时，氯苯的转化率为100％，反应的选择性≥93.8％，产率≥93.8％；与使用由新鲜原料配制的混酸进行反应时相比，氯苯转化率相同，选择性差值<2％，产率差值<2％，废酸的利用效果较好。更多还原

【Abstract】 2,4-dinitrochlorobenzene is an important kind of fine chemicals intermediate, and is used extensively in many fields. So, it has a great developmental future of market. Additionally, there are some disadvantages in the traditional processes, such as environment pollution and energy waste. Therefore, the process of chlorobenzene nitrated to 2,4-dinitrochlorobenzene with continuous and adiabatic nitration was studied. The results are as follows:A set of continuous and adiabatic nitration equipment which included four reactors in series were designed. The equipment was debugged and revised with aqueous simulation experiment, then was debugged and revised with reactants. It fitted in with experimental needs for the process of 2,4-dinitrochlorobenzene.The main influencing factors were investigated with orthogonal test, these factors included: molar ratio of nitric acid to chlorobenzene （φ）, mass fraction of sulfuric acid （S） and quality fraction of nitric acid （N） in mixed acid, volume flux of reactants （Q）. Their influencing order on the reaction was that: N＞Q＞φ＞S.Effects of the above-mentioned each factors on reaction were investigated seriatim with single factor method. The optimal synthesis conditions were obtained, that was:φ=2.22, S=0. 680, N=0.220, W=0. 100（W: mass fraction of water in mixed acid）, Q=16mL.min^-1(Qc=3.46 mL.min^-1（Qc: volume flux of chlorobenzene）), t=40min（t: reaction residence time）. In the optimal condition, conversion rate of chlorobenzene was 100%, selectivity of reaction was 95.4%, yield of products was 95.4%, based on chlorobenzene, content of 2,4-dinitrochlorobenzene in the raw products was 96.39%. Melting point and crystallization point of the raw products were measured, melting point 49.8℃, crystallization point 47.48℃. The stability and repetition of the synthesis experiment were measured and were satisfying, average yield of products in these experiments was over 95%.The crystallization process was studied for raw products to be crystallized with melting crystallization method, the crystallization process was studied, the optimal conditions of crystallization were obtained, that was: in the range of crystallization temperature 47～45℃, descending velocity of crystallization temperature was 3℃.（15.min）^-1, in the range of crystallization temperature 45～22℃, descending velocity of crystallization temperature was 4.5℃.（15.min）^-1, crystallization timeτc was 140min; in the range of exudation temperature 22～43℃, ascending velocity of exudation temperature was 6℃.（15.min）^-1, in the range of exudation temperature 43～46℃, ascending velocity of exudation temperature was 3℃.（15.min）^-1, exudation timeτE was 248min, the whole time of the crystallization experiment was 388min. In the condition, content of 2,4-dinitrochlorobenzene in the end product was 99.10%, based on the quality of the raw product, yield was 91.91%. The stability and repetition of the crystallization experiment were measured and were satisfying, error of these crystallization experiments was not more than 0.03%. Melting point and crystallization point of the end products were measured, melt point was 50. 9℃, crystallization point was 48.61℃. The end products met the national chemical industry criterion of high-grade product HG/T 2553-2003.The disposal and recycle of waste acid were studied. First of all, nitric acid and organic compounds in the waste acid were disposed by the method that chlorobenzene was added into the waste acid and reacted with nitric acid at first, then the outgrowth was extracted. After that, the excess water was removed with distillation and concentration.Both mass fraction of nitric acid and mass fraction of organic compounds in the waste acid disposed were not more than 0.01, mass fraction of sulfuric acid in the waste acid disposed was about 0.92, mass fraction of water in the waste acid disposed was 0.06～0.07. It met the requirement of reuse.In the process which used mixed acid prepared by waste acid disposed, conversion of chlorobenzene was 100%, selectivity was 93.8%. Based on chlorobenzene, yield was 93.8%. In comparition with the process which used the mixed acid prepared with fresh materials, conversion rate of chlorobenzene was the same, difference of their selectivity was not more than 2%, difference of their yield was not more than 2%, the result was satisfying.更多还原