【作者】 杨瑞；

【导师】 郭兴蓬；

【作者基本信息】 华中科技大学 ， 应用化学， 2009， 硕士

【摘要】 4，6-二甲基-2-巯基嘧啶是一种含巯基的氮杂环化合物，有多种互变异构体。其嘧啶环上的双键、N原子以及巯基上的S原子存在孤对电子，可与具有空轨道的金属表面配位，形成金属表面配合物，从而起到缓蚀作用。本文首先参照文献的方法以乙酰丙酮和硫脲为原料合成了一种巯基嘧啶类缓蚀剂A：4，6-二甲基-2-巯基嘧啶。然后通过失重法、动电位扫描技术及红外和红外反射实验研究了缓蚀剂A的吸附行为和缓蚀性能。结果表明，缓蚀剂A在CO2饱和的1%NaCl体系中对N80钢的腐蚀具有较好的抑制作用，在所研究的浓度范围内，其缓蚀效率随缓蚀剂浓度的增加而增加。其在N80钢表面的吸附满足Langmuir吸附等温式，是一种以控制阳极为主的混合型缓蚀剂。随着体系温度的升高，缓蚀剂的缓蚀性能有所下降；在含有0.1 mol/L CH3COOH的CO2饱和1%NaCl体系中，4，6-二甲基-2-巯基嘧啶较咪唑啉类缓蚀剂有更好的缓蚀效率。为了进一步改善缓蚀剂A的缓蚀性能，通过动电位扫描技术及电化学阻抗谱研究了其与一种咪唑啉中间体B的缓蚀协同效应。结果表明，缓蚀剂A与B在复配比为3∶1时具有很好的协同作用，复配后能够显著提高缓蚀剂A的缓蚀性能。协同机理是缘于小分子的4，6-二甲基-2-巯基嘧啶与大分子的咪唑啉中间体在复配后能够在N80钢表面形成更为完整致密的吸附膜。相比于单独使用缓蚀剂A时，复配后的缓蚀剂在抗电偶腐蚀、点蚀及渗氢能力方面都有所提高。更多还原

【Abstract】 4, 6-dimethyl-2-mercaptopyrimidine (Inhibitor A) is a heterocyclic substance containingnitrogen atoms in the pyrimidine ring with a–SH substituent in the lateral chain, it has severalkinds of tautomer. This compound can act as a corrosion inhibitor by adsorbing on the metalsurface through a process of chemisorption forming donor/acceptor interactions between theinhibitor molecules and the vacant d orbital of the iron surface atoms.Inhibitor A was synthesized from acetyl acetone and thiourea following a previouslypublished procedure. Weight-loss method has been applied with potentiodynamic polarizationtechnique to investigate the inhibition efficiency and mechanism. Fourier transform infrared(FTIR) was used to characterize the adsorbed inhibitor film on the N80 steel surface. The resultsindicated that inhibitor A has a good inhibiting efficiency for N80 steel in saturated CO2, 1%NaCl, and the inhibition effect increased gradually with the increasing concentration within therange of concentration studied. Inhibitor A is a mixed inhibitor that mainly restrains the anodicprocess via adsorption on the metal surface, which follows Langmuir adsorption isotherm. Theinhibition efficiency of inhibitor A decreased with the increasing temperature. Inhibitor A has abetter inhibiting efficiency than an imidazoline inhibitor in saturated CO2 solution containing0.1 mol/L CH3COOH and1% NaCl.The synergistic inhibitive effect of inhibitor A and an intermediate (Inhibitor B) wasalso investigated by the potentiodynamic polarization and electrochemical impedancespectroscopy. A synergistic inhibitive effect of the combined inhibitor on the corrosion ofN80 steel was observed. The optimal concentration ratio of inhibitor A to B was 3∶1, andthe inhibitive activity of inhibitor A was greatly improved. The mechanism of thesynergistic effect can be attributed to the form of a more compact inhibiting film when thetwo inhibitors were combined used. The inhibitive activity of the combined inhibitor on thegalvanic corrosion, pitting corrosion and hydrogen permeation, has been greatly improved,when compared with the single use of inhibitor A.更多还原