醇氨法制備吡啶及烷基吡啶
發(fā)布時(shí)間：2019-06-20 03:00
【摘要】：吡啶堿是吡啶及烷基吡啶的總稱，它是化學(xué)工業(yè)特別是精細(xì)化工的極為重要的原料，在農(nóng)藥、醫(yī)藥、飼料等眾多領(lǐng)域內(nèi)具有極為重要而廣泛的應(yīng)用，并且近年來其應(yīng)用領(lǐng)域仍在不斷的擴(kuò)大。吡啶堿的生產(chǎn)包括焦油提取法和化學(xué)合成法。前者因能耗和環(huán)保問題巨大而幾乎被國外所淘汰，但我國仍主要采用此法；后者是國外的主流化工業(yè)生產(chǎn)方法，其主要的工藝路線是甲醛-乙醛/氨法，也存在著原料有毒且成本高等問題。目前，國內(nèi)只有少數(shù)幾家外企和合資企業(yè)正采用甲醛-乙醛/氨法生產(chǎn)吡啶堿，且生產(chǎn)量很低，遠(yuǎn)不能滿足市場需求，每年需要大量從國外進(jìn)口。因此，研究開發(fā)更為有效的制備吡啶堿的技術(shù)顯得非常必要和迫切。 基于上述背景，本論文研究中探索研究了以乙醇/甲醇為碳源，氨水為氨源制備吡啶堿的醇/氨法技術(shù)路線。甲醇、乙醇、氨水是大宗化工基本原料，國內(nèi)供應(yīng)充足，且價(jià)格低廉，以其合成吡啶堿有著極大的市場前景，對我國精細(xì)化工行業(yè)的可持續(xù)發(fā)展有著重要意義。 本文主要采用浸漬法制備了一系列催化劑，并用制備的催化劑開展了醇氨法制備吡啶及吡啶堿反應(yīng)的研究。主要研究結(jié)果如下： 1.發(fā)現(xiàn)無定形的催化劑對于目標(biāo)反應(yīng)幾乎沒有催化作用，而規(guī)整度很好的ZSM-5系列的催化劑的催化性能較好，其中氫型的ZSM-5沸石分子篩表現(xiàn)最佳,吡啶堿的收率為6.12%。在固定載體的情況下，利用金屬鹽采用浸漬法制備不同的改性催化劑，發(fā)現(xiàn)鉍鹽的改性效果最好，吡啶堿的收率為21.66%。采用浸漬法制備了相同負(fù)載量、硅鋁比不同的一系列改性的HZSM-5沸石分子篩催化劑。研究表明硅鋁比為100的HZSM-5分子篩作為催化劑的載體最合適，吡啶堿的收率為30.42%。同樣采用單因素法，發(fā)現(xiàn)鉍鹽的負(fù)載量為20%左右時(shí)的催化效果最理想，吡啶堿的收率為39.04%。 2.對反應(yīng)的工藝條件進(jìn)行了優(yōu)化，目前探索出的最佳工藝條件為：以20%wtBi/HZSM-5(Si/Al=100)作為催化劑，原料配比為乙醇：甲醇：液氨=2：1：3（摩爾比），反應(yīng)溫度為410℃，載氣為空氣且流速為10ml/min，LHSV=0.81h~(-1)。采用上述工藝條件，吡啶、2-甲基吡啶、3/4-甲基吡啶的收率分別為29.88%、2.27%、7.62%。 3.采用XRD、FT-IR、NH3-TPD、低溫氮?dú)馕锢砦椒ǖ榷喾N技術(shù)對所制備的催化劑進(jìn)行表征。發(fā)現(xiàn)以HZSM-5(100)為載體，鉍鹽負(fù)載量在5%~30%區(qū)間時(shí)，隨著鉍鹽負(fù)載量的增加，，催化劑的酸量先減小而后增加，酸強(qiáng)度是先減弱再增強(qiáng)，孔徑先減小后增大，比表面積及孔體積隨之減小。 4.初步探索了醇氨法制備吡啶堿的反應(yīng)機(jī)理，發(fā)現(xiàn)很可能是原料中的醇類先氧化為醛，然后再與氨反應(yīng)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
本文編號(hào)：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
本文編號(hào)：2502861
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