摘要
目的研究生物基甘氨基酸衍生物系列缓蚀剂,N-辛基甘氨酸钠(OCT)和N-十二烷基甘氨酸钠(DOD)在CO_(2)饱和盐水中对N80碳钢的缓蚀效果。方法合成了2种不同碳链长OCT(C8)和DOD(C1_(2))的甘氨基酸型缓蚀剂。通过傅里叶变换红外光谱(FTIR)和核磁共振(NMR)对缓蚀剂的结构进行了表征。利用电化学测试(交流阻抗和极化曲线)、失重法、表面分析技术以及量子化学计算,比较了2种缓蚀剂对N80碳钢的缓蚀性能。结果通过光谱确定了OCT和DOD缓蚀剂结构。腐蚀失重和电化学测试结果显示,OCT和DOD缓蚀剂能够提高N80碳钢在CO_(2)饱和盐水中的抗腐蚀性,随着缓蚀剂浓度的增加,其缓蚀效率逐渐提高。在加入100 mg/L DOD时,缓蚀效率超过94%。扫描电镜(SEM)结果显示,添加DOD缓蚀剂后,N80碳钢表面腐蚀程度显著降低。X射线光电子能谱(XPS)分析表明,OCT和DOD缓蚀剂通过化学吸附作用,在N80碳钢表面形成了保护膜,从而有效延缓了腐蚀过程。量子化学计算结果显示,DOD的最高占据分子轨道(HOMO)与最低未占据分子轨道(LUMO)之间的能量差较小,表明其具有较高的电子转移能力,更易在钢表面吸附形成保护膜,显著降低了腐蚀速率。结论DOD缓蚀剂具有优异的腐蚀防护效果,且随着碳链长度的增加,甘氨基酸缓蚀剂的缓蚀性能增强,使其在N80碳钢表面易吸附并形成有效的保护膜。因此,碳链长的DOD甘氨基酸型缓蚀剂,其缓蚀效果更好。
The work aims to investigate the corrosion inhibition properties of two bio-based amino acid-derived inhibitors,N-octylglycine sodium(OCT)and N-dodecylglycine sodium(DOD),on N80 carbon steel in CO_(2)-saturated brine environments.The two inhibitors with C8 and C1_(2) alkyl chains were synthesized.The structures of the inhibitors were characterized with Fourier-transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR)spectroscopy.The corrosion inhibition properties of OCT and DOD were evaluated through electrochemical tests of electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization curves(PDP),weight loss measurements,surface analysis techniques,and quantum chemical calculations.The FTIR spectra exhibited characteristic absorption peaks corresponding to the functional groups present in both inhibitors,indicating the successful incorporation of the desired chemical structures.NMR spectra provided further information on the molecular structure,confirming the presence of alkyl groups and amino acid functional groups,which supported the successful synthesis of the inhibitors.These results verified that the OCT and DOD inhibitors were synthesized with the intended molecular structures,confirming their potential as effective corrosion inhibitors.The corrosion inhibition properties characterized through weight loss measurements and electrochemical techniques showed that OCT and DOD enhanced the corrosion resistance of N80 carbon steel in CO_(2)-saturated brine.The inhibition efficiency increased with the concentration of the inhibitors,reaching over 94%at 100 mg/L of DOD.EIS results showed that the capacitive arc radius increased with the concentration and carbon chain length of the amino acid-based inhibitors.The potentiodynamic polarization curves indicated that the amino acid-based inhibitors behaved as mixed-type inhibitors in the test environment,with the corrosion current density significantly decreasing as the inhibitor concentration and carbon chain length increased.The trends in inhibition efficiency obtained from both the weight loss method and electrochemical tests were consistent.Scanning electron microscopy(SEM)images showed that the corrosion on the N80 carbon steel surface was significantly reduced after the addition of the DOD inhibitor.The surface appeared smooth and flat,with clear grinding marks visible.This result demonstrated that the amino acid-based inhibitor with a C1_(2) carbon chain provided superior corrosion protection compared to those with C8 carbon chain lengths.In addition,X-ray photoelectron spectroscopy(XPS)analysis confirmed that both OCT and DOD inhibitors formed a protective film on the surface of N80 carbon steel through chemisorption.This protective film served as a barrier,preventing further corrosion and protecting the steel surface from degradation,thereby effectively slowing the corrosion process.Quantum chemical calculations showed that the energy gap between the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)of DOD was less than that of OCT,suggesting that DOD has a higher electron transfer capability.DOD formed a more effective adsorption layer on the surface of N80 carbon steel,leading to a significant reduction in the corrosion rate.The results indicated that DOD with a longer alkyl chain exhibited a higher electron-donating capacity.This enhanced electron donation not only strengthened its adsorption on the steel surface but also facilitated the formation of a more stable and protective film.In conclusion,DOD demonstrates superior corrosion inhibition compared to OCT.DOD with a C12 chain forms a more effective adsorbed film onto the steel surface,which gives higher corrosion resistance.Therefore,cytosine amino acid-based corrosion inhibitors with longer alkyl chains give better performance in CO_(2)-saturated brine environments.
作者
闫坤凤
杨江
赵晓龙
马舒樊
王业飞
杨振
YAN Kunfeng;YANG Jiang;ZHAO Xiaolong;MA Shufan;WANG Yefei;YANG Zhen(College of Petrochemical Engineering,Liaoning Petrochemical University,Liaoning Fushun 113001,China;China Petroleum University(East China),Shandong Qingdao 266000,China)
出处
《表面技术》
北大核心
2025年第12期49-60,共12页
Surface Technology
基金
国家自然科学基金面上项目(52074339)
辽宁省“兴辽英才计划”项目(XLYC1902053)。
关键词
N80碳钢
CO_(2)腐蚀
缓蚀剂
电化学
量子化学计算
N80 carbon steel
CO_(2)corrosion
corrosion inhibitor
electrochemistry
quantum chemical computation
