2-庚烯碳正离子移位及环化反应的分子模拟  

Molecule Simulation of Transpositions and Cyclization Reactions for 2-Heptene Carbonium

作　　者：于宁[1] 龙军[1] 马爱增[1] 周涵[1] 代振宇[1] 赵晓光[1] 赵毅[1] 

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油学报（石油加工）》2013年第4期549-554,共6页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石油化工股份有限公司项目(110096)资助

摘　　要：采用基于密度泛函理论的量子化学方法，研究了催化重整过程中2-庚烯生成碳正离子及碳正离子的移位和环化过程。结果表明，在L酸活性中心作用下，2-庚烯中与双键相连的仲碳上CH键优先发生异裂反应，主要产物为2-庚烯-4-碳正离子；随碳正离子的位置从Cm向cm、C（6]、cm逐步移动，烯烃碳正离子能量逐渐增高，碳正离子移位的反应能垒在104．88～120．80kJ／moI。2-庚烯-4-碳正离子和2-庚烯-5-碳正离子中的碳正离子容易发生移位，生成2-庚烯-6-碳正离子；2-庚烯6-碳正离子和2庚烯-7-碳正离子容易发生五元环环化或六元环环化反应，反应能垒为54．89～59．05kJ／mol。相对碳正离子继续移位生成2-庚烯-7-碳正离子，2-庚烯-6-碳正离子优先发生环化反应，因此2-庚烯催化重整的主要产物具有五元环分子结构。Based on density functional theory （DFT） quantum chemical methods, the process of carbonium transposition and cyclization reactions of 2-heptene carbonium was studied. The results showed that in the exist of Lewis acid the heterolytic dissociation of the C H bond on the secondary carbon next to the double bond in 2-heptene molecule occurred preferentially to obtain the main product of 2-heptene-4-carbonium. With the carbonium transposition step by step from C（4） to C（5）, C（6） , C（7） in 2-heptene carbonium, the energy of heptene-carboniums gradually increased, and the energy of reaction barrier of carbonium transpositions was in the range of 104.88--120.80 kJ/mol. 2-Heptene-4-carbonium and 2-heptene-5-carbonium could easily become 2-heptene-6-carbonium by the carbonium transposition, and 2-heptene-6-carbonium and 2-heptene-7-carbonium could easily become five membered ring or six mcmbered ring products by cyclization with the energy of reaction barrier in the range of 54.89-- 59.05 kJ/mol. 2-Heptene-6-carbonium preferred to cyclize to five membered ring product rather than to transpose to 2-heptene-7-carbonium, so the main product of the catalytic reforming of 2-heptene was of five membered ring structure.

关 键 词：2-庚烯 碳正离子 环化反应 分子模拟 

分 类 号：TE624[石油与天然气工程—油气加工工程]