【作者】 张海江；

【导师】 陈新志；

【作者基本信息】 浙江大学 ， 化学工程， 2008， 硕士

【摘要】 有机胺是重要的有机化工中间体，在医药、农药等方面有着广泛的应用。本文研究了管道化反应器中以二氯乙烷和氨水为原料合成了乙二胺的工艺。在内径4mm，长度13m的管道反应器中，较适宜工艺条件为：氨水浓度60％（质量分数），氨与二氯乙烷摩尔比为30：1，体积流量2L／h，温度160℃，压力6MPa，二氯乙烷单程转化率98．7％，乙二胺收率51．6％。本文假设：（1）反应过程中氨的浓度为一常数；（2）反应主产物为乙二胺，副产物为二乙烯三胺，不考虑其它多胺；（3）反应器内的流动状态为理想平推流，由此建立了二氯乙烷氨化反应的表观动力学模型。结合不同温度下反应中各组分浓度随时间变化的实验数据，得到下列表观速率方程式：其中C_A为二氯乙烷的浓度，C_B为乙二胺的浓度，C_C二乙烯三胺的浓度。主反应速率常数k₁=1．3211×10⁶×e^-53144／RT，主反应活化能为53144J／mol，副反应速率常数k₂=1．5594×10⁸×e^-73997／RT，副反应活化能为73997J／mol。从动力学方程可知主反应的活化能要小于副反应。根据化学反应动力学原理，高温对于活化能高的反应有利，因此采用变温工艺对提高目标产品收率有利。具体工艺为：前期反应温度较高，提高主反应的反应速率；后期反应温度较低，抑制副反应速度。基于得到的动力学方程，对变温反应工艺进行了模拟计算。结果表明变温反应工艺与等温反应工艺相比，在相同的管道长度下提高了产品收率。将一段式等温管道化反应器改进为两段式变温管道化反应器，在内径4mm，总长度27m的反应器中，较适宜工艺条件为：第一段管道反应温度为160℃，反应时间1．5min，第二段管道温度130℃，反应时间8．5min，其它工艺条件（物料配比、体积流量和体系压力等）与等温反应工艺一致。在此工况下，二氯乙烷的单程转化率可达98．6％，乙二胺收率60．1％。如在等温反应工艺中要达到相同的收率，其较适合工艺为：反应温度130℃，反应时间15min（对应管道长度为40m）。比较可知，变温反应工艺在相同产品收率的条件下将管道长度缩短了33％，减少了设备投资。反应粗产品液经过闪蒸脱氨、中和、蒸水、共沸蒸馏、萃取除水等后处理步骤得到了浓度为96％的乙二胺溶液。更多还原

【Abstract】 Amines are important intermediates for organic chemical industry. A large number of drugs, pesticides and dyes are made from them.Ethylenediamine was prepared by aminolysis of dichlorethane with a tubular reactor in this paper.The effects of several factors were investigated and the optimized conditions in the isothermal tubular reactor with inner diameter of 4mm and length of 13m were: the molar ratio of ammonia and dichlorethane 30:1, the concentration of the ammonia 60%, the volume velocity 2L/h, the reaction temperature 160℃, the system pressure 6MPa. Thus the conversion of dichlorethane was 98.7% per pass and the yield was 51.6%.The apparent kinetics of the reaction was studied on some assumed conditions as follows: the only by-product of the reaction is diethylenetriamine; the concentration of ammonia is regarded as constant; the fluid state in the reactor is ideal plug flow. The apparent kinetics equations were established as follows:in which C_A was the concentration of dichlorethane, C_B was the concentration of ethylenediamine, C_C was the concentration of diethylenetriamine. The rate constant of main reaction k₁=1.3211×10⁶×e^-53144/RT, the rate constant of side reactionk₂=1.5594×10⁸×e^-73997/RT.The activity energy of the main and side reaction were53144J/mol and 73997J/mol respectively.The activity energy of the main reaction was lower than that of the side reaction according to the kinetics equations. It was known that higher temperature was favorable to the reaction which had higher activity energy. Therefore the non-isothermal reaction was considered to be suitable to improve the selectivity of ethylenediamine. High temperature was adopted in early period to improve the main reaction rate and low temperature was adopted in later period to restrain the side reaction. Compared to the isothermal reaction with the same length of the reactor pipe, the yield of the target product was increased by caculations based on the kinetics equations obtained above.By investigating the effects of several factors in the non-isothermal tubular reactor with inner diameter of 4mm and the overall length of 27m, the optimized conditions were: the temperature of the first reaction pipe 160℃, the reaction time 1.5min. The temperature of second reaction pipe 130℃, the reaction time 8.5min. The other conditions were the same as in isothermal reaction. Thus the conversion of dichlorethane was 98.6% per pass and the yield was 60.1%. To achieve the same yield in isothermal reaction, the suitable conditions were: the temperature 130℃, the reaction time 15min （the length of the pipe was 40m correspondingly）. The length of the reactor pipe was shortened by 33% compared to the isothermal reaction.The ethylenediamine solution with the concentration of 96% was obtained from the crude product through flash evaporation, neutralization, dehydration, azeotropic distillation and extraction.更多还原