Abstract

The structure–activity relationship of ten mercaptoalcohol molecules as corrosion inhibitors for carbon steel was investigated through quantum chemistry calculation and molecular dynamics simulation (MD). Quantum chemical parameters including the energy of the highest occupied molecular orbital (E_HOMO) and the lowest unoccupied molecular orbital (E_LUMO), energy gap (ΔE), electronegativity (χ) have been calculated to investigate the relationship between the corrosion inhibition performance and the molecular structure. Quantum chemical parameters show the corrosion inhibition performance is strengthened with the lengthening of the carbon chain. The theoretical inhibition efficiency increases with the increasing of the length of carbon chain. As a result, the C_11 molecule presents the best corrosion inhibition performance among the studied molecules. At the same time, molecular dynamics simulation results indicate that both the –SH and –OH can be adsorbed onto the Fe (1 1 0) surface and the molecular plane is parallel to the Fe (1 1 0) surface. The absolute values of the adsorption energy increases with the lengthening of the carbon chain. According to the adsorption energy, the longer of the carbon chain is, the easier it is for molecule to be adsorbed onto the Fe (1 1 0) surface. As a result, the corrosion inhibition performance of the mercaptoalcohol molecules becomes better with the lengthening of the carbon chain, and the C_11 molecule is the best one.

中文翻译：

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用第一性原理和分子动力学模拟研究巯基醇作为缓蚀剂的缓蚀性能

摘要

通过量子化学计算和分子动力学模拟（MD）研究了十种巯基醇分子作为碳钢缓蚀剂的构效关系。量子化学参数包括最高占据分子轨道（E _HOMO）和最低未占据分子轨道（E _LUMO）的能，能隙（ΔE），已计算出电负性（χ）以研究缓蚀性能与分子结构之间的关系。量子化学参数表明，随着碳链的延长，缓蚀性能增强。理论上的抑制效率随着碳链长度的增加而增加。结果，在所研究的分子中，C_11分子表现出最佳的缓蚀性能。同时，分子动力学模拟结果表明–SH和–OH均可以吸附到Fe（1 1 0）表面，并且分子平面平行于Fe（1 1 0）表面。吸附能的绝对值随着碳链的延长而增加。根据吸附能，碳链越长，分子更容易被吸附到Fe（1 1 0）表面上。结果，随着碳链的延长，巯基醇分子的腐蚀抑制性能变得更好，并且C_11分子是最好的。