TAPO-5分子篩催化環(huán)己酮氨肟化反應(yīng)性能的研究
發(fā)布時間：2019-05-25 00:01
【摘要】：環(huán)己酮肟是尼龍-6纖維和工程塑料產(chǎn)業(yè)鏈的主要組成部分。目前工業(yè)上主要采用環(huán)己酮-羥胺法生產(chǎn)環(huán)己酮肟,該工藝存在制備過程復(fù)雜、產(chǎn)率較低、設(shè)備易受損、環(huán)境污染嚴(yán)重等問題。為提高工業(yè)生產(chǎn)的經(jīng)濟(jì)與環(huán)境效益,研究者一直探索開發(fā)新型合成路線。環(huán)己酮肟液相氨肟化合成法是新型綠色合成工藝,但反應(yīng)過程中使用的催化劑TS-1因生產(chǎn)成本高、易失活、難回收等問題限制了該工藝的推廣。設(shè)計、開發(fā)新型高效催化劑體系來替代TS-1,仍是研究者關(guān)注的焦點。過渡金屬鈦原子取代的磷酸鋁分子篩(TAPO-5),由于結(jié)構(gòu)規(guī)整、組成均勻、同時具有Lewis酸和反應(yīng)活性中心,成為最有研究前景的催化劑。本文采用水熱法進(jìn)行TAPO-5分子篩的制備,系統(tǒng)考察了鈦含量、晶化時間、焙燒氣氛等因素對TAPO-5分子篩物化性質(zhì)及催化性能的影響。采用XRD、XRF、N2物理吸附、DR UV-Vis、Raman、Py-FTIR等方法對分子篩的晶體結(jié)構(gòu)、比表面積、酸性質(zhì)、分子篩骨架中的鈦含量及不同鈦物種等物化性質(zhì)進(jìn)行表征,考察不同條件下制備的TAPO-5分子篩催化環(huán)己酮液相氨肟化性能,并對其催化活性及影響因素進(jìn)行分析探討。主要結(jié)論有以下方面:(1)Ti作為催化反應(yīng)的活性中心,TAPO-5分子篩中隨著Ti含量的增加,環(huán)己酮液相氨肟化反應(yīng)的收率逐漸增大,但同時分子篩中鈦含量的增加造成了結(jié)晶度降低,微孔、介孔孔道結(jié)構(gòu)減少;(2)在TAPO-5分子篩中,引入的Ti原子主要有三種存在形式:骨架Ti,非骨架Ti及銳鈦礦型TiO2。Py-FTIR的分析表明,非骨架Ti能產(chǎn)生相應(yīng)的L酸性,在一定程度上有助于催化環(huán)己酮氨肟化;(3)使用模板法,在(N_2-H_2)混合氣氛中焙燒模板劑,以此對分子篩進(jìn)行碳改性,并用于催化環(huán)己酮氨肟化,結(jié)果表明:隨焙燒溫度的升高,模板劑碳化程度逐漸增加,在氨肟化反應(yīng)中,反應(yīng)的選擇性也逐漸增大,最高為91.7%。
[Abstract]:Cyclohexanone oxime is the main part of nylon-6 fiber and engineering plastic industry chain. At present, Cyclohexanone oxime is mainly produced by cyclohexanone-hydroxyamine method in industry. There are some problems in this process, such as complex preparation process, low yield, easy damage of equipment, serious environmental pollution and so on. In order to improve the economic and environmental benefits of industrial production, researchers have been exploring and developing a new synthetic route. The liquid phase ammonia oximation synthesis of cyclohexanone oximate is a new green synthesis process, but the catalyst TS-1 used in the reaction process is limited because of its high production cost, easy deactivation and difficult recovery. The design and development of a new type of high efficiency catalyst system to replace TS-1, is still the focus of researchers. Aluminum phosphate molecular sieves (TAPO-5) replaced by transition metal titanium atoms have become the most promising catalyst because of their regular structure and uniform composition, as well as Lewis acid and reactive sites. In this paper, TAPO-5 molecular sieves were prepared by hydrothermal method. The effects of titanium content, crystallization time and calcination atmosphere on the physical and chemical properties and catalytic properties of TAPO-5 molecular sieves were investigated systematically. The crystal structure, specific surface area, acid properties, titanium content in molecular sieves skeleton and physical and chemical properties of different titanium species were characterized by XRD,XRF,N2 physical adsorption and DR UV-Vis,Raman,Py-FTIR. The catalytic performance of TAPO-5 molecular sieves in liquid phase ammoximation of cyclohexanone under different conditions was investigated, and its catalytic activity and influencing factors were analyzed and discussed. The main conclusions are as follows: (1) Ti is used as the active center of catalytic reaction. With the increase of Ti content in TAPO-5 molecular sieves, the yield of liquid phase aminooximation of cyclohexanone increases gradually. At the same time, the increase of titanium content in molecular sieves resulted in the decrease of crystallinity, micropores and mesoporous pore structures. (2) in TAPO-5 molecular sieves, there are three main forms of Ti atoms: skeleton Ti, non-skeleton Ti and anatase TiO2.Py-FTIR analysis show that non-skeleton Ti can produce corresponding L acidity. To a certain extent, it is helpful to catalyze the ammoximation of cyclohexanone. (3) the molecular sieves were modified by using template method and calcined in (N_2-H_2) mixed atmosphere. The results showed that with the increase of calcination temperature, the molecular sieves were modified by carbon and used to catalyze the ammonia oximation of cyclohexanone. The carbonation degree of template increased gradually, and the selectivity of the reaction increased gradually in the ammoximation reaction, the highest was 91.7%.
【學(xué)位授予單位】：山西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O621.251
本文編號：2485306
[Abstract]:Cyclohexanone oxime is the main part of nylon-6 fiber and engineering plastic industry chain. At present, Cyclohexanone oxime is mainly produced by cyclohexanone-hydroxyamine method in industry. There are some problems in this process, such as complex preparation process, low yield, easy damage of equipment, serious environmental pollution and so on. In order to improve the economic and environmental benefits of industrial production, researchers have been exploring and developing a new synthetic route. The liquid phase ammonia oximation synthesis of cyclohexanone oximate is a new green synthesis process, but the catalyst TS-1 used in the reaction process is limited because of its high production cost, easy deactivation and difficult recovery. The design and development of a new type of high efficiency catalyst system to replace TS-1, is still the focus of researchers. Aluminum phosphate molecular sieves (TAPO-5) replaced by transition metal titanium atoms have become the most promising catalyst because of their regular structure and uniform composition, as well as Lewis acid and reactive sites. In this paper, TAPO-5 molecular sieves were prepared by hydrothermal method. The effects of titanium content, crystallization time and calcination atmosphere on the physical and chemical properties and catalytic properties of TAPO-5 molecular sieves were investigated systematically. The crystal structure, specific surface area, acid properties, titanium content in molecular sieves skeleton and physical and chemical properties of different titanium species were characterized by XRD,XRF,N2 physical adsorption and DR UV-Vis,Raman,Py-FTIR. The catalytic performance of TAPO-5 molecular sieves in liquid phase ammoximation of cyclohexanone under different conditions was investigated, and its catalytic activity and influencing factors were analyzed and discussed. The main conclusions are as follows: (1) Ti is used as the active center of catalytic reaction. With the increase of Ti content in TAPO-5 molecular sieves, the yield of liquid phase aminooximation of cyclohexanone increases gradually. At the same time, the increase of titanium content in molecular sieves resulted in the decrease of crystallinity, micropores and mesoporous pore structures. (2) in TAPO-5 molecular sieves, there are three main forms of Ti atoms: skeleton Ti, non-skeleton Ti and anatase TiO2.Py-FTIR analysis show that non-skeleton Ti can produce corresponding L acidity. To a certain extent, it is helpful to catalyze the ammoximation of cyclohexanone. (3) the molecular sieves were modified by using template method and calcined in (N_2-H_2) mixed atmosphere. The results showed that with the increase of calcination temperature, the molecular sieves were modified by carbon and used to catalyze the ammonia oximation of cyclohexanone. The carbonation degree of template increased gradually, and the selectivity of the reaction increased gradually in the ammoximation reaction, the highest was 91.7%.
【學(xué)位授予單位】：山西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O621.251
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