嘧啶类缓蚀剂对酸性介质中奥氏体不锈钢的缓蚀量化构效影响研究

目的使用基于密度泛函(DFT)的量子化学法,研究嘧啶类缓蚀剂的分子结构和在酸性介质中对碳钢的缓蚀效率之间的关系。方法通过计算前线轨道能量(最高占据轨道和最低空轨道)、电荷分布、绝对电负性(χ)、偶极矩(μ)和转移电子数(ΔN)等量化参数,确定与缓蚀效率之间的关系。结果DHPMs缓蚀剂的缓蚀效率随着EHOMO值的增大而提高,随着ELUMO值的减小而提高,随着前线轨道能级差值(ELUMO-EHOMO)的减小而提高,随着转移电子数ΔN增大而提高。含有N原子的区域最有可能失电子并吸附在金属铁表面活性位置。结论由于DHPMⅠ的嘧啶环供电子能力较强,致使DHPMⅠ比DHPMⅡ的缓蚀效率高。

Effects of Pyrimidine Derivative Corrosion Inhibitors on the Anti-corrosion Quantitative Structure-activity Relationship of Austenitic Stainless Steel in Acidic Media

ABSTRACT:Objective Quantum chemical calculations based on DFT method was used to study the relationship between the mo-lecular structure and inhibition efficiency of pyrimidine derivatives ( DHPMs) used as corrosion inhibitors for carbon steel in acidic media. Methods The quantitative parameters, such as the frontier molecular orbital energy HOMO ( highest occupied molecular or-bital) and LUMO ( lowest unoccupied molecular orbital) , the charge distribution of the studied inhibitors, the absolute electroneg-ativity (χ) values, dipole moment(μ) and the fraction of electrons (△N) transferred from inhibitors to carbon steel were calculated and correlated with inhibition efficiencies. Results The results showed that the inhibition efficiency of DHPMs increased with the increase in EHOMO , the decrease in ELUMO , the decrease in ELUMO-EHOMO , and the increase in the number of the fraction of electrons (△N) transferred from inhibitors to carbon steel. The areas containing N atoms were the most possible sites for bonding the active sites on the metal iron surface by donating electrons to the metal. Conclusion Compound DHPMⅠhad higher inhibition efficiency than DHPM II, because the pyrimidine ring of DHPMⅠ had stronger electron donating capacity.