(1. 桂林理工大學(xué) 化學(xué)與生物工程學(xué)院，桂林 541004；2. 陜西咸陽化學(xué)工業(yè)有限公司，咸陽 712000)
摘 要: 利用鄰氧乙酸苯甲醛縮對氨基苯磺酸鉀鹽席夫堿(K2L)緩蝕劑在20#碳鋼表面制備自組裝單分子膜(SAMs)，并通過電化學(xué)方法研究緩蝕劑自組裝膜的最佳組裝時間；采用電化學(xué)測試技術(shù)和表面分析技術(shù)研究K2L- SAMs對碳鋼在飽和CO2油田水介質(zhì)中的緩蝕行為；采用密度泛函理論分析緩蝕劑分子的前線軌道、Mulliken電荷和分子靜電勢。結(jié)果表明：緩蝕劑在碳鋼表面自組裝3 h后，可以形成穩(wěn)定、致密的緩蝕膜；在碳鋼表面形成的K2L-SAMs能有效抑制碳鋼的陰極還原過程，最高緩蝕效率達87.55%；K2L的吸附行為符合Langmuir吸附等溫式，吸附機理為典型的化學(xué)吸附。量子化學(xué)計算結(jié)果表明：羧基是K2L分子的主要吸附活性區(qū)域，能與碳鋼表面鐵原子作用形成穩(wěn)定的配位鍵。
關(guān)鍵字: 碳鋼；自組裝膜；席夫堿；電化學(xué)測試；緩蝕機理；量子化學(xué)計算
（1. College of Chemical and Biological Engineering, Guilin University of Technology, Guilin 541004, China;
2. Shaanxi Xianyang Chemical Industrial Co., Ltd., Xianyang 712000, China）
Abstract:The self-assembled monolayers (SAMs) were prepared on the surface of 20# carbon steel by using 2-[(4-sulfonic potassium phenyl imino) methylene] phenoxyacetic acid potassium salt (K2L) as corrosion inhibitor, and the best self-assembled time of the SAMs on the surface of carbon steel was investigated by electrochemical methods. The inhibition behavior of the K2L-SAMs with the carbon steel in CO2-saturated oilfield water was studied by electrochemical test technology and surface analysis technique. The frontier orbitals, Mulliken charges and molecular electrostatic potential of the corrosion inhibitor were analyzed by the density functional theory. The results show that the corrosion inhibitor can form stable and compact corrosion SAM on the surface of carbon steel after 3 h immersion in the aqueous solution of the corrosion inhibitor. The processes of cathodic reduction are restrained by the steady K2L-SAMs on the surface of carbon steel, and the highest inhibition efficiency is 87.55%. The adsorption behavior of the K2L-SAMs on the carbon steel surface follows the Langmuir adsorption isotherm, and the adsorption mechanism is typically chemical adsorption. Quantum chemistry calculation results show that carboxyl is mainly active area of the adsorption of K2L molecule, which can interact with Fe atoms on the carbon steel surface by the stable coordination bonds.
Key words: carbon steel; self-assembled monolayer; Schiff base; electrochemical test; inhibition mechanism; quantum chemistry calculation
