摘要
利用Benson基团贡献法计算了乙烯齐聚制α-烯烃反应各物质的标准摩尔生成焓、标准摩尔熵和摩尔定压热容,在298～700 K温度范围内对乙烯齐聚制α-烯烃反应体系的反应热、吉布斯自由能以及反应平衡常数进行了详尽的计算,分析了不同反应步骤的热力学平衡与限度,对不同反应发生的热力学可能性与顺序进行了判断,考察了反应温度和压力对乙烯齐聚制α-烯烃反应化学平衡的影响,确定了乙烯齐聚制α-烯烃反应体系适宜的工艺条件.结果表明:乙烯齐聚制α-烯烃反应为放热反应;从热力学上看,温度低于546 K时,乙烯齐聚生成直链α-烯烃反应为自发过程,且比α-烯烃异构化和烯烃歧化反应更容易进行;低温、高压有利于乙烯齐聚制α-烯烃反应的进行;乙烯齐聚制α-烯烃反应体系适宜的工艺条件为温度323～473 K,压力5～20 MPa,且在SHOP法的工艺条件下(温度363 K,压力10.3 MPa),乙烯齐聚生成直链α-烯烃反应的热力学平衡转化率接近于100%.
The standard molar enthalpy of formation, the standard molar entropy and isobaric molar heat capacity of ethylene oligomerization products were estimated with Benson group contribution method. The reaction heat, Gibbs free energy change and equilibrium constant of ethylene oligomerization to t^-olefin reaction system were calculated in detail as a function of the temperature from 298 K to 700 K. The thermodynamic equilibrium and the limit of dif- ferent reaction steps were analyzed. The thermodynamic possibility and formation sequences of ethylene oligomeriza- tion reaction system were also judged. The effects of temperature and pressure on the equilibrium conversion were investigated. The appropriate process conditions of ethylene oligomerization to ct-olefin reactions were determined according to thermodynamic calculations. The results show that ethylene oligomerization to ct-olefin reactions are ex- othermic reactions, which are spontaneous when the temperature is lower than 546 K. The ethylene oligomerization to linear c^-olefin reactions are easier than t^-olefin isomerization and internal olefin disproportionations. Low tem- perature and high pressure are favored to ethylene oligomerizations to ct-olefin reactions from the thermodynamic view point. The appropriate process conditions of ethylene oligomerization to ct-olefins are 323 -473 K, 5 -20 MPa. The equilibrium conversions of ethylene oligomerization to linear a-olefin reactions approach 100% in the process conditions of 363 K, I0.3 MPa from SHOP method.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2013年第4期385-391,共7页
Journal of Molecular Catalysis(China)
基金
国家重点基础研究发展计划(973计划
2012CB723603)
关键词
乙烯齐聚
Α-烯烃
热力学
平衡常数
ethylene oligomerization
ct-olefin
thermodynamics
equilibrium constant
