醇氨法制备吡啶及烷基吡啶
发布时间：2019-06-20 03:00
【摘要】：吡啶碱是吡啶及烷基吡啶的总称，它是化学工业特别是精细化工的极为重要的原料，在农药、医药、饲料等众多领域内具有极为重要而广泛的应用，并且近年来其应用领域仍在不断的扩大。吡啶碱的生产包括焦油提取法和化学合成法。前者因能耗和环保问题巨大而几乎被国外所淘汰，但我国仍主要采用此法；后者是国外的主流化工业生产方法，其主要的工艺路线是甲醛-乙醛/氨法，也存在着原料有毒且成本高等问题。目前，国内只有少数几家外企和合资企业正采用甲醛-乙醛/氨法生产吡啶碱，且生产量很低，远不能满足市场需求，每年需要大量从国外进口。因此，研究开发更为有效的制备吡啶碱的技术显得非常必要和迫切。 基于上述背景，本论文研究中探索研究了以乙醇/甲醇为碳源，氨水为氨源制备吡啶碱的醇/氨法技术路线。甲醇、乙醇、氨水是大宗化工基本原料，国内供应充足，且价格低廉，以其合成吡啶碱有着极大的市场前景，对我国精细化工行业的可持续发展有着重要意义。 本文主要采用浸渍法制备了一系列催化剂，并用制备的催化剂开展了醇氨法制备吡啶及吡啶碱反应的研究。主要研究结果如下： 1.发现无定形的催化剂对于目标反应几乎没有催化作用，而规整度很好的ZSM-5系列的催化剂的催化性能较好，其中氢型的ZSM-5沸石分子筛表现最佳,吡啶碱的收率为6.12%。在固定载体的情况下，利用金属盐采用浸渍法制备不同的改性催化剂，发现铋盐的改性效果最好，吡啶碱的收率为21.66%。采用浸渍法制备了相同负载量、硅铝比不同的一系列改性的HZSM-5沸石分子筛催化剂。研究表明硅铝比为100的HZSM-5分子筛作为催化剂的载体最合适，吡啶碱的收率为30.42%。同样采用单因素法，发现铋盐的负载量为20%左右时的催化效果最理想，吡啶碱的收率为39.04%。 2.对反应的工艺条件进行了优化，目前探索出的最佳工艺条件为：以20%wtBi/HZSM-5(Si/Al=100)作为催化剂，原料配比为乙醇：甲醇：液氨=2：1：3（摩尔比），反应温度为410℃，载气为空气且流速为10ml/min，LHSV=0.81h~(-1)。采用上述工艺条件，吡啶、2-甲基吡啶、3/4-甲基吡啶的收率分别为29.88%、2.27%、7.62%。 3.采用XRD、FT-IR、NH3-TPD、低温氮气物理吸附法等多种技术对所制备的催化剂进行表征。发现以HZSM-5(100)为载体，铋盐负载量在5%~30%区间时，随着铋盐负载量的增加，，催化剂的酸量先减小而后增加，酸强度是先减弱再增强，孔径先减小后增大，比表面积及孔体积随之减小。 4.初步探索了醇氨法制备吡啶碱的反应机理，发现很可能是原料中的醇类先氧化为醛，然后再与氨反应生成吡啶和烷基吡啶。
[Abstract]:Pyridine base is the general name of pyridine and alkyl pyridine. It is a very important raw material in chemical industry, especially in fine chemical industry. It has a very important and extensive application in many fields, such as pesticides, medicine, feed and so on. In recent years, its application field is still expanding. The production of pyridine base includes tar extraction and chemical synthesis. The former is almost eliminated by foreign countries because of the huge energy consumption and environmental protection problems, but the latter is still mainly used in China, the latter is the mainstream chemical industry production method abroad, its main process route is formaldehyde-acetaldehyde / ammonia method, and there are also some problems, such as toxic raw materials and high cost. At present, only a few foreign enterprises and joint ventures are using formaldehyde-acetaldehyde / ammonia method to produce pyridine base, and the production is very low, far from meeting the market demand, a large number of imports from abroad are needed every year. Therefore, it is very necessary and urgent to study and develop a more effective technology for the preparation of pyridine base. Based on the above background, the alcohol / ammonia method for the preparation of pyridine base with ethanol / methanol as carbon source and ammonia as ammonia source was studied in this paper. Methanol, ethanol and ammonia are the basic raw materials of bulk chemical industry. The domestic supply is sufficient and the price is low. Because of its great market prospect for the synthesis of pyridine base, it is of great significance to the sustainable development of fine chemical industry in China. In this paper, a series of catalysts were prepared by impregnation method, and the reaction of pyridine and pyridine base prepared by alcohol-ammonia method was studied. The main results are as follows: 1. It was found that amorphous catalysts had little catalytic effect on the target reaction, while ZSM-5 series catalysts with good regularity had better catalytic performance, among which hydrogen type ZSM-5 zeolites were the best, and the yield of pyridine base was 6.12%. Under the condition of fixed support, different modified catalysts were prepared by impregnation of metal salt. It was found that bismuth salt had the best modification effect, and the yield of pyridine base was 21.66%. A series of modified HZSM-5 molecular sieves catalysts with the same loading and different Si-Al ratio were prepared by dipping method. The results show that HZSM-5 molecular sieves with Si / Al ratio of 100 are the most suitable catalysts, and the yield of pyridine base is 30.42%. It was also found that the catalytic effect of bismuth salt was the best when the loading of bismuth salt was about 20%, and the yield of pyridine base was 39.04%. two銆
本文编号：2502861
[Abstract]:Pyridine base is the general name of pyridine and alkyl pyridine. It is a very important raw material in chemical industry, especially in fine chemical industry. It has a very important and extensive application in many fields, such as pesticides, medicine, feed and so on. In recent years, its application field is still expanding. The production of pyridine base includes tar extraction and chemical synthesis. The former is almost eliminated by foreign countries because of the huge energy consumption and environmental protection problems, but the latter is still mainly used in China, the latter is the mainstream chemical industry production method abroad, its main process route is formaldehyde-acetaldehyde / ammonia method, and there are also some problems, such as toxic raw materials and high cost. At present, only a few foreign enterprises and joint ventures are using formaldehyde-acetaldehyde / ammonia method to produce pyridine base, and the production is very low, far from meeting the market demand, a large number of imports from abroad are needed every year. Therefore, it is very necessary and urgent to study and develop a more effective technology for the preparation of pyridine base. Based on the above background, the alcohol / ammonia method for the preparation of pyridine base with ethanol / methanol as carbon source and ammonia as ammonia source was studied in this paper. Methanol, ethanol and ammonia are the basic raw materials of bulk chemical industry. The domestic supply is sufficient and the price is low. Because of its great market prospect for the synthesis of pyridine base, it is of great significance to the sustainable development of fine chemical industry in China. In this paper, a series of catalysts were prepared by impregnation method, and the reaction of pyridine and pyridine base prepared by alcohol-ammonia method was studied. The main results are as follows: 1. It was found that amorphous catalysts had little catalytic effect on the target reaction, while ZSM-5 series catalysts with good regularity had better catalytic performance, among which hydrogen type ZSM-5 zeolites were the best, and the yield of pyridine base was 6.12%. Under the condition of fixed support, different modified catalysts were prepared by impregnation of metal salt. It was found that bismuth salt had the best modification effect, and the yield of pyridine base was 21.66%. A series of modified HZSM-5 molecular sieves catalysts with the same loading and different Si-Al ratio were prepared by dipping method. The results show that HZSM-5 molecular sieves with Si / Al ratio of 100 are the most suitable catalysts, and the yield of pyridine base is 30.42%. It was also found that the catalytic effect of bismuth salt was the best when the loading of bismuth salt was about 20%, and the yield of pyridine base was 39.04%. two銆
本文编号：2502861
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