Study on synthesis of m-dinitrobenzene based on continuous flow reaction
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摘要: 采用微通道反应器进行硝基苯硝化工艺的探索.通过调节硫酸质量分数、硝酸与硫酸摩尔比、硝酸与硝基苯摩尔比、反应温度和停留时间等参数，优化各实验参数后，得到最佳反应条件：硫酸质量分数为92%，硝酸与硫酸摩尔比为1∶5.3，硝基苯和硝酸摩尔比为1∶1.15，反应温度为85 ℃，停留时间为70 s.实验结果：硝基苯的平均转化率为99.2%，主产物间二硝基苯的平均收率为85.5%，对二硝基苯的平均收率为3.5%，邻二硝基苯的平均收率为10.2%. 利用微反应器进行硝基苯硝化时，通过补加浓硫酸和发烟硝酸，可实现废酸的循环利用，使其更加绿色安全环保.Abstract: The process of nitrobenzene nitration was explored by using microchannel reactor. By adjusting concentration of sulfuric acid, molar ratio of nitric acid to sulfuric acid, molar ratio of nitric acid to nitrobenzene, reaction temperature and residence time, the optimal reaction conditions were obtained as follows: the concentration of sulfuric acid was 92%, molar ratio of nitric acid to sulfuric acid was 1∶5.3, molar ratio of nitrobenzene to nitric acid was 1∶1.15, reaction temperature was 85 ℃, and residence time was 70 s. The experimental result shows that average conversion of nitrobenzene is 99.2%, average yield of m-dinitrobenzene is 85.5%, average yield of p-dinitrobenzene is 3.5%, and average yield of o-dinitrobenzene is 10.2%. When nitrobenzene is nitrated in micro reactor, the waste acid can be recycled by adding concentrated sulfuric acid and fuming nitric acid, which will make it more green, safe and environmentally friendly.
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Key words:
- microchannel reactor /
- nitrobenzene /
- nitrification
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图 2 间二硝基苯制备的连续流程图
Figure 2. Continuous-flow process diagram for the preparation of m-dinitrobenzene
图 3 硫酸浓度对NB转化率和产物产率的影响
Figure 3. Effect of sulfuric acid concentration on conversion of NB and product productivity
图 4 n(H2SO4)∶ n(HNO3)对NB转化率和产物产率的影响
Figure 4. Effect of molar ratio of H2SO4 and HNO3 on conversion of NB and product productivity
图 5 n(HNO3)∶ n(NB)对NB转化率和产物产率的影响
Figure 5. Effect of the molar ratio of HNO3 and NB on conversion of NB and product productivity
图 6 反应温度对NB转化率和产物产率的影响
Figure 6. Effect of reaction temperature on conversion of NB and product productivity
图 7 保留时间对NB转化率和产物产率的影响
Figure 7. Effect of retention time on conversion of NB and product productivity
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