甲烷等离子体转化合成碳二烃反应过程和过渡态理论

• REACTION KINETICS, CATALYSIS AND…… • 上一篇下一篇

甲烷等离子体转化合成碳二烃反应过程和过渡态理论

王保伟^a; 杨恩翠^b; 许根慧^a; 郝金库^b

^a Key Laboratory for Green Chemical Technology of State Education Ministry, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China ^b College of Chemistry and Life Sciences, Tianjin Normal University, Tianjin 300074, China

收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2007-02-28 发布日期:2007-02-28
通讯作者: 王保伟

Theoretical study of reaction paths and transition states on conversion methane into C₂hydrocarbons through plasma

WANG Baowei^a; YANG Encui^b; XU Genhui^a; HAO Jinku^b

^aKey Laboratory for Green Chemical Technology of State Education Ministry, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China ^b College of Chemistry and Life Sciences, Tianjin Normal University, Tianjin 300074, China

Received:1900-01-01 Revised:1900-01-01 Online:2007-02-28 Published:2007-02-28
Contact: WANG Baowei

摘要/Abstract

摘要： The direct synthesis of C2 hydrocarbons (ethylene, acetylene and ethane) from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be realized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths (1)—(4) were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap (MNDO)] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond order and intrinsic reaction coordinate. The reaction heat results indicate that the reactions (2) and (4) are exothermic, while reactions of (1) and (3) are endothermic. The activation energy results show that activation energy for reac-tions (1) and (2) was much lower than that of reaction paths (3) and (4). Therefore, paths (1) and (2) is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated (IRC) of the reaction paths (1) and (2), it is found that the variations of bond lengths in reaction path (1) has a crucial effect on the poten-tial energy, while in reaction path (2), the adjustment of the system geometry also contributes to the whole potential energy of the system.

关键词: reaction path;transition state;methane;plasma;PM3

Abstract: The direct synthesis of C2 hydrocarbons (ethylene, acetylene and ethane) from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be realized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths (1)—(4) were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap (MNDO)] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond order and intrinsic reaction coordinate. The reaction heat results indicate that the reactions (2) and (4) are exothermic, while reactions of (1) and (3) are endothermic. The activation energy results show that activation energy for reac-tions (1) and (2) was much lower than that of reaction paths (3) and (4). Therefore, paths (1) and (2) is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated (IRC) of the reaction paths (1) and (2), it is found that the variations of bond lengths in reaction path (1) has a crucial effect on the poten-tial energy, while in reaction path (2), the adjustment of the system geometry also contributes to the whole potential energy of the system.

Key words: reaction path, transition state, methane, plasma, PM3

王保伟, 杨恩翠, 许根慧, 郝金库. 甲烷等离子体转化合成碳二烃反应过程和过渡态理论[J]. , DOI: .

WANG ,Baowei, YANG ,Encui, ,XU ,Genhui, HAO ,Jinku. Theoretical study of reaction paths and transition states on conversion methane into C₂hydrocarbons through plasma[J]. , DOI: .

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