Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts
The production of vinyl chloride (VCM) by pyrolysis of 1,2-dichloroethane (DCE) is an important process in the ethylene-based poly(vinyl chloride) industry. The pyrolysis is performed at temperatures above 500 °C, gives low conversions, and has high energy consumption. We have shown that N-doped car...
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MDPI AG
2020-06-01
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| Series: | Catalysts |
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| author | Zhaobing Shen Yejun Han Yue Liu Yejun Qin Ping Xing Hong Zhao Biao Jiang |
| author_facet | Zhaobing Shen Yejun Han Yue Liu Yejun Qin Ping Xing Hong Zhao Biao Jiang |
| author_sort | Zhaobing Shen |
| collection | DOAJ |
| description | The production of vinyl chloride (VCM) by pyrolysis of 1,2-dichloroethane (DCE) is an important process in the ethylene-based poly(vinyl chloride) industry. The pyrolysis is performed at temperatures above 500 °C, gives low conversions, and has high energy consumption. We have shown that N-doped carbon catalysts give excellent performances in DCE dehydrochlorination at 280 °C. The current understanding of the active sites, mechanism, and kinetics of DCE dehydrochlorination over N-doped carbon catalysts is limited. Here, we showed that pyridinic-N on a N-doped carbon catalyst is the active site for catalytic production of vinyl chloride monomer from DCE. The results of CO<sub>2</sub> and DCE temperature-programmed desorption experiments showed that the pyridinic-N catalytic sites are basic, and the mechanism of dehydrochlorination on a N-doped carbon catalyst involves a carbanion. A kinetic study of dehydrochlorination showed that the surface reaction rate on the N-doped carbon catalyst was the limiting step in the catalytic dehydrochlorination of DCE. This result enabled clarification of the dehydrochlorination mechanism and optimization of the reaction process. These findings will stimulate further studies to increase our understanding of the relationship between the base strength and catalytic performance. The results of this study provide a method for catalyst optimization, namely modification of the amount of pyridinic-N and the base strength of the catalyst, to increase the surface reaction rate of DCE dehydrochlorination on N-doped carbon catalysts. |
| first_indexed | 2024-03-10T18:56:25Z |
| format | Article |
| id | doaj.art-81ceafb52cbb48848326e8cb68c97005 |
| institution | Directory Open Access Journal |
| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-10T18:56:25Z |
| publishDate | 2020-06-01 |
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| series | Catalysts |
| spelling | doaj.art-81ceafb52cbb48848326e8cb68c970052023-11-20T04:46:37ZengMDPI AGCatalysts2073-43442020-06-0110670710.3390/catal10060707Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon CatalystsZhaobing Shen0Yejun Han1Yue Liu2Yejun Qin3Ping Xing4Hong Zhao5Biao Jiang6Shanghai Green Chemical Engineering Research Center, Shanghai Institute of Organic Chemistry, No. 345 Lingling Road, Shanghai 200032, ChinaGreen Chemical Engineering Research Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Zhangjiang Hi-Tech Park, Pudong, Shanghai 201210, ChinaGreen Chemical Engineering Research Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, No. 99 Haike Road, Zhangjiang Hi-Tech Park, Pudong, Shanghai 201210, ChinaShanghai Green Chemical Engineering Research Center, Shanghai Institute of Organic Chemistry, No. 345 Lingling Road, Shanghai 200032, ChinaShanghai Green Chemical Engineering Research Center, Shanghai Institute of Organic Chemistry, No. 345 Lingling Road, Shanghai 200032, ChinaShanghai Green Chemical Engineering Research Center, Shanghai Institute of Organic Chemistry, No. 345 Lingling Road, Shanghai 200032, ChinaShanghai Green Chemical Engineering Research Center, Shanghai Institute of Organic Chemistry, No. 345 Lingling Road, Shanghai 200032, ChinaThe production of vinyl chloride (VCM) by pyrolysis of 1,2-dichloroethane (DCE) is an important process in the ethylene-based poly(vinyl chloride) industry. The pyrolysis is performed at temperatures above 500 °C, gives low conversions, and has high energy consumption. We have shown that N-doped carbon catalysts give excellent performances in DCE dehydrochlorination at 280 °C. The current understanding of the active sites, mechanism, and kinetics of DCE dehydrochlorination over N-doped carbon catalysts is limited. Here, we showed that pyridinic-N on a N-doped carbon catalyst is the active site for catalytic production of vinyl chloride monomer from DCE. The results of CO<sub>2</sub> and DCE temperature-programmed desorption experiments showed that the pyridinic-N catalytic sites are basic, and the mechanism of dehydrochlorination on a N-doped carbon catalyst involves a carbanion. A kinetic study of dehydrochlorination showed that the surface reaction rate on the N-doped carbon catalyst was the limiting step in the catalytic dehydrochlorination of DCE. This result enabled clarification of the dehydrochlorination mechanism and optimization of the reaction process. These findings will stimulate further studies to increase our understanding of the relationship between the base strength and catalytic performance. The results of this study provide a method for catalyst optimization, namely modification of the amount of pyridinic-N and the base strength of the catalyst, to increase the surface reaction rate of DCE dehydrochlorination on N-doped carbon catalysts.https://www.mdpi.com/2073-4344/10/6/707kineticsmechanismdehydrochlorination of 1,2-dichloroethaneN-doped carbon |
| spellingShingle | Zhaobing Shen Yejun Han Yue Liu Yejun Qin Ping Xing Hong Zhao Biao Jiang Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts Catalysts kinetics mechanism dehydrochlorination of 1,2-dichloroethane N-doped carbon |
| title | Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts |
| title_full | Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts |
| title_fullStr | Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts |
| title_full_unstemmed | Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts |
| title_short | Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts |
| title_sort | understanding surface basic sites of catalysts kinetics and mechanism of dehydrochlorination of 1 2 dichloroethane over n doped carbon catalysts |
| topic | kinetics mechanism dehydrochlorination of 1,2-dichloroethane N-doped carbon |
| url | https://www.mdpi.com/2073-4344/10/6/707 |
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