由苯胺和乙二醇一步催化合成吲哚的研究
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摘要
吲哚作为一种重要的有机原料和精细化工产品在工业、农业和医药等领域中应用非常广泛。一步法由苯胺和乙二醇合成吲哚是吲哚众多合成方法中最为经济的一种。本论文以浸渍-程序升温焙烧-原位还原方法制备用于苯胺和乙二醇一步合成吲哚的Ag／SiO_2催化剂，通过XRD、TEM、TG、DSC及XPS等表征手段对银催化剂进行了深入研究，并对二氧化硅担载的铜催化剂进行了探讨。主要得到了如下实验结果：
1 通过浸渍-程序升温焙烧-原位还原制备的Ag／SiO_2催化剂，当银微晶小于10纳米时，催化剂活性和选择性较高，其吲哚收率为78％，达到了通过共沉淀方法制备的、已工业应用的银催化剂的最好水平。
2 Ag／SiO_2催化剂在反应过程中存在失活现象。催化剂的TG、XRD和TEM表征表明，Ag／SiO_2催化剂失活的主要原因是反应过程中催化剂表面的积碳和银粒子的烧结。向反应体系加入水蒸气和氢气能有效减少催化剂表面的积碳。加入水蒸气还能抑制乙二醇的分解，促使吲哚从催化剂表面快速脱附，从而使吲哚选择率大大提高。
3 ZnO作为一种结构助剂能高度分散活性组分银，有效抑制反应过程中银粒子的烧结，其结果大大提高了催化剂的稳定性。加入CeO_2助剂及FeO助剂不仅可以较大程度地提高吲哚收率，而且能显著增强催化剂的稳定性。以分步浸渍法制备的Ag-FeO／SiO_2-ZnO-CeO_2催化剂，反应第10小时，吲哚收率能达到87％以上，该结果比文献报道的已工业应用的银催化剂的最好水平高出近10％。
4 根据量化计算和实验结果提出二氧化硅担载的银催化剂上苯胺和乙二醇合成吲哚的反应历程为：
摘 要
A．。；，＾。。，。，AftwMCHodHgOH r。llJ＋11 rha－一
月丫HO－HZC 陀．【圆 ／、一一——‘’“－‘卜g Iw 厂I厂河
4v－xNH，HO－HZ6－HZOlx＝，ar－HZO·－hZ WtN－
‘”t—－NhZ H
I
首先，乙二醇上的一个羟基与苯胺分子氨基邻位的碳上的氢反应脱去一分子水生成中间
产物邻一氨基苯乙醇OX 然后邻一氨基苯乙醇经过脱水环化、脱氢生成目的产物悄跌。其
中苯胺和乙二醇生成邻一氨基苯乙醇的过程是一慢反应，邻一氨基苯乙醇生成阿跌的过程
较快。
5 以等体积浸渍制备的Cu／SIOZ催化剂活性很高，其悄吸收率可以达到88％，但催
化剂在反应中也存在失活。催化剂的EA、XRD及TG表征表明，CujsiO。催化剂失活的
主要原因是反应过程中催化剂表面上的积碳。向反应体系加水蒸气和氢气可以减少催化
剂表面上的积碳。向 Cu／SIOZ催化剂中加入ZnO助剂和 Fe、Co、Ni等过渡金属助剂都
不能使催化剂性能得到提高。加入zno助剂导致二氧化硅上的cuo难以还原。
Indole, which is an important raw organic material and fine chemical product, has many uses in the fields of industry, agriculture and medicine. There are many known methods to produce indole. One of the most promising routes, from an economic point of view, seems to be the direct catalytic synthesis from aniline and ethylene glycol. In this dissertation, the synthesis of indole from aniline and ethylene glycol catalyzed by Ag/SiO2 catalyst , prepared by impregnation-programm heating calcination-insitu reduction method, has been investigated by means of some characterizations such as XRD, TEM. TG. DSC and XPS. Copper-based catalyst was also studied for this reaction. The main results are summarised as follows:
catalyst prepared by impregnation-programm heating calcination-insitu reduction method exhibits high activity and selectivity in the synthesis of indole when the silver crystallite size is smaller than 10 nm. And the yield of indole could reach 78%, which is as high as the best result in the literature reported for the industrialized silver catalyst prepared by co-deposition method.
2 It has been found that the activity of Ag/SiOz catalyst declined with reaction time. The characterization of the catalyst by TG. XRD and TEM indicates that the main reasons for the deactivation are the carbon-deposition on the catalyst surface and the sintering of silver particle during the reaction. And the carbon-deposition could be decreased efficiently by introducing steam and hydrogen into the reaction system. The other effect of the steam in the reaction is that it could restrain glycol breaking up and enhance desorption of indole from the catalyst surface, therefore greatly increase the indole selectivity.
3 As a structure promoter, ZnO in the catalyst could efficiently improve the dispersion of silver on the support and block the sintering of silver crystallite during the reaction process. Consequently the stability of the catalyst is increased. The addition of CeO2 and FeO to the silver-based catalyst could increase not only the yield of indole, but also the stability of the
in
ABSTRACT
catalyst. For Ag-FeO/SiO2-ZnO-CeO2 catalyst prepared by step-by-step impregnation method. the yield of indole still keeps higher than 87% after the reaction for 10 h. This is about 10% higher than the best result in the literature for the industrialized silver catalyst.
4 Based on the quantum chemistry calculation and the experimented results, the pathway of iodole synthesis from aniline and ethylene glycol on the silver catalyst supported on silica can be proposed schematically as follows:
HO-H2C fcgUSlow] x0"20"20" Kg!. [Fast] HO.H2i -H2?
First, Glycol and aniline reacts by dehydration and produce the intermediate product of (1) o-amino-phenylethanol. Then the intermediate 1 could produce the target product of indole by dehydration and dehydrogenation. Comparing the two steps, the first step for producing o-amino-phenylethanol from glycol and aniline is slow, namely, this step is the rate-determining step. And the step for producing indole from the intermediate 1 is the fast.
5 It has been also found that Cu/SiC>2 catalyst prepared by incipient impregnation method shows very high activity with the yield of indole up to 88%, but this catalyst is also deactivated during the reaction. The main reason for the deactivation of Cu/SiCh catalyst is the carbon-deposition on the catalyst surface during the reaction. Introducing hydrogen and steam into the reaction system could decrease the carbon-deposition. Addition of Zn, Fe, Co and Ni oxides to Cu/SiC>2 catalyst negtively affects the performance of the catalyst. And CuO/SiC>2 is hard to be reduced when ZnO is added to it.
1 通过浸渍-程序升温焙烧-原位还原制备的Ag／SiO_2催化剂，当银微晶小于10纳米时，催化剂活性和选择性较高，其吲哚收率为78％，达到了通过共沉淀方法制备的、已工业应用的银催化剂的最好水平。
2 Ag／SiO_2催化剂在反应过程中存在失活现象。催化剂的TG、XRD和TEM表征表明，Ag／SiO_2催化剂失活的主要原因是反应过程中催化剂表面的积碳和银粒子的烧结。向反应体系加入水蒸气和氢气能有效减少催化剂表面的积碳。加入水蒸气还能抑制乙二醇的分解，促使吲哚从催化剂表面快速脱附，从而使吲哚选择率大大提高。
3 ZnO作为一种结构助剂能高度分散活性组分银，有效抑制反应过程中银粒子的烧结，其结果大大提高了催化剂的稳定性。加入CeO_2助剂及FeO助剂不仅可以较大程度地提高吲哚收率，而且能显著增强催化剂的稳定性。以分步浸渍法制备的Ag-FeO／SiO_2-ZnO-CeO_2催化剂，反应第10小时，吲哚收率能达到87％以上，该结果比文献报道的已工业应用的银催化剂的最好水平高出近10％。
4 根据量化计算和实验结果提出二氧化硅担载的银催化剂上苯胺和乙二醇合成吲哚的反应历程为：
摘 要
A．。；，＾。。，。，AftwMCHodHgOH r。llJ＋11 rha－一
月丫HO－HZC 陀．【圆 ／、一一——‘’“－‘卜g Iw 厂I厂河
4v－xNH，HO－HZ6－HZOlx＝，ar－HZO·－hZ WtN－
‘”t—－NhZ H
I
首先，乙二醇上的一个羟基与苯胺分子氨基邻位的碳上的氢反应脱去一分子水生成中间
产物邻一氨基苯乙醇OX 然后邻一氨基苯乙醇经过脱水环化、脱氢生成目的产物悄跌。其
中苯胺和乙二醇生成邻一氨基苯乙醇的过程是一慢反应，邻一氨基苯乙醇生成阿跌的过程
较快。
5 以等体积浸渍制备的Cu／SIOZ催化剂活性很高，其悄吸收率可以达到88％，但催
化剂在反应中也存在失活。催化剂的EA、XRD及TG表征表明，CujsiO。催化剂失活的
主要原因是反应过程中催化剂表面上的积碳。向反应体系加水蒸气和氢气可以减少催化
剂表面上的积碳。向 Cu／SIOZ催化剂中加入ZnO助剂和 Fe、Co、Ni等过渡金属助剂都
不能使催化剂性能得到提高。加入zno助剂导致二氧化硅上的cuo难以还原。
Indole, which is an important raw organic material and fine chemical product, has many uses in the fields of industry, agriculture and medicine. There are many known methods to produce indole. One of the most promising routes, from an economic point of view, seems to be the direct catalytic synthesis from aniline and ethylene glycol. In this dissertation, the synthesis of indole from aniline and ethylene glycol catalyzed by Ag/SiO2 catalyst , prepared by impregnation-programm heating calcination-insitu reduction method, has been investigated by means of some characterizations such as XRD, TEM. TG. DSC and XPS. Copper-based catalyst was also studied for this reaction. The main results are summarised as follows:
catalyst prepared by impregnation-programm heating calcination-insitu reduction method exhibits high activity and selectivity in the synthesis of indole when the silver crystallite size is smaller than 10 nm. And the yield of indole could reach 78%, which is as high as the best result in the literature reported for the industrialized silver catalyst prepared by co-deposition method.
2 It has been found that the activity of Ag/SiOz catalyst declined with reaction time. The characterization of the catalyst by TG. XRD and TEM indicates that the main reasons for the deactivation are the carbon-deposition on the catalyst surface and the sintering of silver particle during the reaction. And the carbon-deposition could be decreased efficiently by introducing steam and hydrogen into the reaction system. The other effect of the steam in the reaction is that it could restrain glycol breaking up and enhance desorption of indole from the catalyst surface, therefore greatly increase the indole selectivity.
3 As a structure promoter, ZnO in the catalyst could efficiently improve the dispersion of silver on the support and block the sintering of silver crystallite during the reaction process. Consequently the stability of the catalyst is increased. The addition of CeO2 and FeO to the silver-based catalyst could increase not only the yield of indole, but also the stability of the
in
ABSTRACT
catalyst. For Ag-FeO/SiO2-ZnO-CeO2 catalyst prepared by step-by-step impregnation method. the yield of indole still keeps higher than 87% after the reaction for 10 h. This is about 10% higher than the best result in the literature for the industrialized silver catalyst.
4 Based on the quantum chemistry calculation and the experimented results, the pathway of iodole synthesis from aniline and ethylene glycol on the silver catalyst supported on silica can be proposed schematically as follows:
HO-H2C fcgUSlow] x0"20"20" Kg!. [Fast] HO.H2i -H2?
First, Glycol and aniline reacts by dehydration and produce the intermediate product of (1) o-amino-phenylethanol. Then the intermediate 1 could produce the target product of indole by dehydration and dehydrogenation. Comparing the two steps, the first step for producing o-amino-phenylethanol from glycol and aniline is slow, namely, this step is the rate-determining step. And the step for producing indole from the intermediate 1 is the fast.
5 It has been also found that Cu/SiC>2 catalyst prepared by incipient impregnation method shows very high activity with the yield of indole up to 88%, but this catalyst is also deactivated during the reaction. The main reason for the deactivation of Cu/SiCh catalyst is the carbon-deposition on the catalyst surface during the reaction. Introducing hydrogen and steam into the reaction system could decrease the carbon-deposition. Addition of Zn, Fe, Co and Ni oxides to Cu/SiC>2 catalyst negtively affects the performance of the catalyst. And CuO/SiC>2 is hard to be reduced when ZnO is added to it.
引文
1 王大全主编《精细化工词典》，化学工业出版社，1998年，1页
2 实用精细化学品手册编写组，章思规主编《实用精细化学品手册》，化学工业出版社，1996年，1529页
3 王世椿编著《染料化学》下册，化学工业出版社，1954年，413页
4 精细化学品辞典编辑委员会，禹茂章等译校《精细化学品辞典》，化学工业出版社，1987年，590页
5 花文廷编著《杂环化学》，北京大学出版社，1990年，264页
6 化工百科全书编辑委员会，陈冠荣主编《化工百科全书》，化学工业出版社，1990年，987页
7 同4，911页
8 Telang N.T., Katdare M., Bradlow H.L., Osborne M.P., Fishman J., "Inhibition of proliferation and modulation of estradiol metabolism: novel mechanisms for breast cancer prevention by the phytochemical indole-3-carbinol" ,Proc. Soc.Exp. Biol.Med., 1997, 216 (2):246
9 Kodera Y., Ukegawa K., Mito Y., etc.," Solvent extraction of nitrogen compounds from coal liquids", Fuel,1991,70 (6):765
10 清浦忠光，“触媒使用制造，触媒，1998，40(2)：92
11 Eur. Pat. Appl. EP., 427, 287(1991)
12 石雷，王新平，蔡天锡，“吲哚环化合物合成方法的进展”，有机化学，2001，21(3)：200
13 Eur.Pat.Appl.EP.,69,242(1983)
2 实用精细化学品手册编写组，章思规主编《实用精细化学品手册》，化学工业出版社，1996年，1529页
3 王世椿编著《染料化学》下册，化学工业出版社，1954年，413页
4 精细化学品辞典编辑委员会，禹茂章等译校《精细化学品辞典》，化学工业出版社，1987年，590页
5 花文廷编著《杂环化学》，北京大学出版社，1990年，264页
6 化工百科全书编辑委员会，陈冠荣主编《化工百科全书》，化学工业出版社，1990年，987页
7 同4，911页
8 Telang N.T., Katdare M., Bradlow H.L., Osborne M.P., Fishman J., "Inhibition of proliferation and modulation of estradiol metabolism: novel mechanisms for breast cancer prevention by the phytochemical indole-3-carbinol" ,Proc. Soc.Exp. Biol.Med., 1997, 216 (2):246
9 Kodera Y., Ukegawa K., Mito Y., etc.," Solvent extraction of nitrogen compounds from coal liquids", Fuel,1991,70 (6):765
10 清浦忠光，“触媒使用制造，触媒，1998，40(2)：92
11 Eur. Pat. Appl. EP., 427, 287(1991)
12 石雷，王新平，蔡天锡，“吲哚环化合物合成方法的进展”，有机化学，2001，21(3)：200
13 Eur.Pat.Appl.EP.,69,242(1983)