改性咪唑啉类缓蚀剂缓蚀机理的分子模拟  

Molecular simulation of imidazoline corrosion inhibition by modification

作　　者：魏晓静[1,2] 石鑫 葛鵬莉[1] 高多龙[1] 闻小虎 WEI Xiao-jing;SHI Xin;GE Peng-li;GAO Duo-long;WEN Xiao-hu(SINOPEC Northwest Company of China Petroleum and Chemical Corporation,Urumqi 830011,China;Key Laboratory of Enhanced Oil Recovery in Carbonate Fractured-vuggy Reservoirs,SINOPEC,Urumqi 830011,China)

机构地区：[1]中国石油化工股份有限公司西北油田分公司,新疆乌鲁木齐830011 [2]中国石油化工集团公司碳酸盐岩缝洞型油藏提高采收率重点实验室,新疆乌鲁木齐830011

出　　处：《分子科学学报》2021年第4期352-359,共8页Journal of Molecular Science

基　　金：中国石油化工股份有限公司顺北一区矿山运输系统防腐技术研究与应用资助项目(P18022-5)。

摘　　要：基于密度泛函理论和分子动力学分别研究了油酸咪唑啉(C17)、季铵化改性咪唑啉(QI)和环氧乙烷改性咪唑啉(EOI)的反应活性、吸附方式、吸附强度和最优吸附构型,揭示了3种缓蚀剂的缓蚀机理.结果表明:3种缓蚀剂分子的反应活性区域主要分布在咪唑环、头基的N原子以及苯环上;3种缓蚀剂分子的缓蚀能力大小为QI>EOI>C17;根据缓蚀剂与金属成键原子态密度可知,咪唑环中N原子的s轨道和p轨道与Cu原子的d轨道发生杂化耦合,形成化学键.本文评价了3种咪唑啉类缓蚀剂的缓蚀性能,明确了咪唑啉类缓蚀剂的缓蚀机理,提供了一种高效的缓蚀剂设计、评价和筛选思路.In this article, density functional theory and molecular dynamics are used to study the molecular activity and adsorption mechanism of three imidazole molecular corrosion inhibitors including traditional imidazoline oleic acid imidazoline(C17), quaternized modified imidazoline(QI) and ethylene oxide modified imidazoline(EOI). The molecular frontier orbital energy, Fukui index and atomic charge of the three corrosion inhibitor molecules are obtained through DMol3 quantum chemistry calculation, showing that the reactive regions of the three corrosion inhibitor molecules are mainly distributed on the imidazole ring, the N atom of the head group and the benzene ring. The order of the corrosion inhibition performance of three corrosion inhibitor molecules is QI>EOI>C17. Through the calculation of the optimal configuration, we find that the three corrosion inhibitor molecules get attached to the surface of metal mainly relying on the N atoms on the imidazoline ring, and the adsorption strength is consistent with the corrosion inhibition performance of the corrosion inhibitor. According to the density of state of the bond atom between corrosion inhibitors and the surface of metal, s orbital and p orbital of N atom on imidazole ring and d orbital of Cu atom are hybridized and coupled to form chemical bond, i.e., corrosion inhibitor molecules form a film on the surface of metal. Using molecular dynamics simulation, the interaction between corrosion inhibitor molecules and the surface of metal was studied, and the corrosion inhibition performance and mechanism of conventional imidazoline and modified imidazoline were compared. The results show that the corrosion of metal is due to the interaction balance between H2O molecules in the dense layer of water on the surface of metal and the corrosive medium. When there are corrosion inhibitor molecules in the system, the corrosion inhibitor molecules replace part of the H2O molecules in the dense water layer on the surface of metal, i.e., reduce the number of particles for the i

关 键 词：咪唑啉 缓蚀剂 分子动力学模拟 密度泛函理论 

分 类 号：O639[理学—高分子化学]