Abstract:

Alanine hydrochloride was prepared from alanine, then its derivative was synthesized by amidation. The structure of the synthesized product was characterized by infrared and ¹H nuclear magnetic resonance. The corrosion inhibition effect of alanine and alanine derivative on carbon steel at 30 ℃ in 0.5 mol/L sulfuric acid medium was studied by weight loss method, electrochemical method and scanning electron microscope. The results showed that alanine derivative had better corrosion inhibition than alanine due to the hydrophobic alkane long chain. The weight loss method and electrochemistry showed that the corrosion inhibition rate reached more than 90% at the alanine derivative dosage of 300 mg/L. The adsorption of corrosion inhibitor on carbon steel surface conformed to Langmuir adsorption model. Alanine derivative at low mass concentrations(50-100 mg/L) could inhibit the oxidation of anode metal,which was anode corrosion inhibitor. At higher mass concentrations(200-500 mg/L), the rate of hydrogen evolution reaction at the cathode and metal oxidation reaction at the anode was reduced at the same time, thus reducing the overall corrosion reaction rate, so alanine derivative was a mixed corrosion inhibitor.

Key words: corrosion inhibitor, alanine, alanine derivatives, carbon steel

摘要：

以丙氨酸为原料制备丙氨酸盐酸盐，再通过酰胺化反应，合成丙氨酸衍生物，采用红外和核磁共振氢谱对产物结构进行了表征。利用失重法、电化学方法和扫描电镜研究了丙氨酸及丙氨酸衍生物在30 ℃、0.5 mol/L硫酸介质中对碳钢的缓蚀效果。结果表明，丙氨酸衍生物由于增加了疏水烷烃长链，缓蚀效果明显优于丙氨酸。失重法和电化学法缓蚀性能测试均表明在丙氨酸衍生物投加量300 mg/L时，缓蚀率即可达到90%以上。缓蚀剂在碳钢表面的吸附符合Langmuir吸附模型。丙氨酸衍生物在较低质量浓度（50~100 mg/L）时对阳极金属氧化反应起到抑制作用，为阳极型缓蚀剂；在较高质量浓度（200~500 mg/L）时会同时降低阴极析氢反应和阳极金属氧化反应的速率，从而降低整体腐蚀反应的速率，为混合型缓蚀剂。

关键词: 缓蚀剂, 丙氨酸, 丙氨酸衍生物, 碳钢

CLC Number: 

• TG174.42