双子型咪唑啉季铵盐缓蚀剂的制备及缓蚀机理

Preparation and inhibition mechanism of gemini imidazoline quaternary ammonium salt inhibitor

为了减缓油气集输过程中管线设备腐蚀的问题,以油酸、羟乙基乙二胺和1,6-二氯己烷为原料合成了双子型咪唑啉季铵盐。利用傅里叶变换红外光谱仪(FTIR)和核磁共振波谱仪(^(1)H NMR)对缓蚀剂结构进行表征;采用静态失重法和电化学法评价了缓蚀剂的缓蚀性能;利用X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和电子能谱仪(EDS)对腐蚀产物进行表征和分析,并对该缓蚀剂的缓蚀机理进行了探讨。静态失重实验表明,当双子型咪唑啉季铵盐浓度为100mg/L时,在40℃、5%NaCl饱和CO_(2)水溶液中能使N80碳钢的腐蚀速率降至0.0569mm/a,缓蚀率达90.74%;极化曲线结果表明,该缓蚀剂属于混合抑制型缓蚀剂,电化学腐蚀电流密度从122μA/cm^(2)减小到14.5μA/cm^(2),缓蚀率达88.11%;交流阻抗谱结果表明,该缓蚀剂能吸附在金属表面改变其金属/溶液的界面性质,从而减缓腐蚀反应的进行,缓蚀率达88.95%且与静态失重和极化曲线测试结果具有较好的一致性;XPS、SEM和EDS测试结果证明,双子型咪唑啉季铵盐缓蚀剂能在N80碳钢表面形成吸附膜以减缓腐蚀。

In order to alleviate the corrosion of pipeline equipment in the process of oil and gas gathering and transportation,the gemini imidazoline quaternary ammonium salt was synthesized from oleic acid,hydroxyethyl ethylenediamine and 1,6-dichlorohexane.The structure of the inhibitor was characterized by FTIR and ^(1)H NMR.The inhibition performance of the inhibitor was evaluated by static weight loss method and electrochemical method.The corrosion products were characterized and analyzed by X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and electronic energy spectroscopy(EDS),and the inhibition mechanism of the inhibitor was discussed.The static weight loss experiment showed that when the concentration of gemini imidazoline quaternary ammonium salt was 100mg/L,the corrosion rate of N80 carbon steel could be reduced to 0.0569mm/a at 40℃in 5%NaCl saturated CO_(2) aqueous solution and the corrosion inhibition rate could reach 90.74%.The polarization curve results indicated that the inhibitor belonged to a mixed inhibition inhibitor and the electrochemical corrosion current density was reduced from 122μA/cm^(2) to 14.5μA/cm^(2) with the corrosion inhibition rate of 88.11%.The results of AC impedance spectroscopy found that the inhibitor could adsorb on the metal surface and change the interface property of the metal/solution,and thus slowing down the corrosion reaction.The inhibition rate was 88.95%,which was in good agreement with the results of static weight loss and polarization curve tests.XPS,SEM and EDS test results showed that the gemini imidazoline quaternary ammonium salt inhibitor could form an adsorption film on the surface of N80 carbon steel to slow down the corrosion.