The corrosion of mild steel pipelines is a tough issue during the extraction of oil and gas. In this work, two novel thiadiazole derivatives, 5-(benzylthio)-1,3,4-thiadiazol-2-amine (BTTA) and 5,5′-disulfanediylbis (1,3,4-thiadiazol-2-amine) (DSTA), were synthesized as inhibitors for the corrosion of mild steel in the CO₂-saturated oilfield produced water. Their inhibitive effects and mechanisms were studied by electrochemical measurements, surface characterization, quantum chemical calculations and molecular dynamics (MD) simulations. It is shown that both DSTA and BTTA exhibit high inhibition efficiencies. Especially for DSTA, the inhibition efficiency reaches 98.7% even in a fairly low concentration of 0.0025 mM, and reaches 99.37% with a concentration of 0.025 mM. DSTA presents a better inhibitive performance than BTTA in low concentration. These two thiadiazole derivatives act as mixed type inhibitors with predominant anodic effectiveness, and their adsorptions on mild steel surface follow the Langmuir adsorption isotherm. According to the experimental results and theoretical calculations, the inhibitive mechanisms of BTTA and DSTA are discussed.

在开采石油和天然气期间，低碳钢管道的腐蚀是一个棘手的问题。在这项工作中，两个新颖的噻二唑衍生物5-（苄硫基）-1,3,4-噻二唑-2-胺（BTTA）和5,5'-二硫代二磺基双（1,3,4-噻二唑-2-胺）（合成DSTA）作为低碳钢在CO _2中的腐蚀抑制剂饱和油田采出水。通过电化学测量，表面表征，量子化学计算和分子动力学（MD）模拟研究了它们的抑制作用和机理。结果表明，DSTA和BTTA均显示出高抑制效率。特别是对于DSTA，即使在相当低的0.0025 mM浓度下，抑制效率也达到98.7％，而在0.025 mM浓度下则达到99.37％。在低浓度下，DSTA具有比BTTA更好的抑制性能。这两种噻二唑衍生物作为混合型抑制剂具有主要的阳极效力，它们在低碳钢表面的吸附遵循Langmuir吸附等温线。根据实验结果和理论计算，探讨了BTTA和DSTA的抑制机理。