分子内氢键对屏蔽酚抗氧化活性的影响  

Influence of Intramolecular Hydrogen Bond on the Antioxidant Activity of Hindered Phenols

作　　者：苏朔[1] 龙军[1] 段庆华[1] 周涵[1] 武志强[1] 赵毅[1] 王立华[1] 李新华[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）》2014年第5期772-778,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石油化工股份有限公司项目(S112015)基金资助

摘　　要：采用基于密度泛函理论的量子化学从头算法计算了不同分子结构屏蔽酚的O—H键解离能(EBD),采用压力差示扫描量热仪测定了屏蔽酚在润滑油基础油中的抗氧化活性,考察了屏蔽酚的EBD与其抗氧化活性之间的关系,并重点探究了结构因素对邻位桥联屏蔽双酚EBD的影响。结果表明,屏蔽酚的活性构象EBD越小,其抗氧化活性越高。分子内氢键对邻位桥联屏蔽双酚的EBD可以产生显著影响。对于邻位桥联屏蔽双酚分子而言,其最低能量构象存在2个O—H┅π氢键,EBD较高,并非抗氧化活性构象;存在1个O—H┅O氢键的局部最低能量构象,EBD相对较低,为抗氧化活性构象。邻位亚甲基桥联屏蔽双酚分子的内旋转能垒较低,容易形成EBD较低的活性构象,这是其抗氧化效果突出的主要原因。Quantum chemistry method based on density functional theory was applied to calculate the bond dissociation energy（EBD）of the O—H bond of different types of hindered phenols.The antioxidant activity of hindered phenols in lubricating base oil was verified by using pressurized differential scanning calorimeter.The relationship between the EBD of hindered phenols and their antioxidant activity was investigated,and the influences of structure factors on the EBDof hindered orthobisphenols were analyzed.Results indicated that activity conformations of hindered phenols with lower EBD had higher antioxidant activity in lubricating base oil.The intramolecular hydrogen bond had a significant impact on the EBD of hindered ortho-bisphenol.For hindered ortho-bisphenols,their lowest energy conformations had higher EBDand were not antioxidant activity conformations due to the formation of two O—H┅πbonds,while the local minimum energy conformations with a O—H┅O hydrogen bond and much lower EBDwere their antioxidant activity conformations.In addition,the lower intramolecular rotation energy barrier played a main role in lowering EBDof methene bridged ortho-bisphenol,which was the main reason for its excellent antioxidant performance.

关 键 词：屏蔽酚 键解离能 密度泛函理论 抗氧化活性 分子内氢键 内旋转 

分 类 号：TE626[石油与天然气工程—油气加工工程]