哌嗪类曼尼希碱壳聚糖缓蚀剂的制备及缓蚀性能研究

目的 解决海底采油设备酸化腐蚀问题，合成一种绿色的哌嗪类曼尼希碱壳聚糖衍生物缓蚀剂CS-NMB，并研究其在15%（质量分数）盐酸溶液中对N80钢的缓蚀性能，计算研究其在金属表面的作用机理。方法 以曲酸和N–甲基哌嗪为原料，经过曼尼希反应，合成曼尼希碱（MB），再将该曼尼希碱接枝到壳聚糖分子上。采用红外光谱表征所合成产物，利用电化学法和静态失重法评价CS-N-MB在该强酸环境中对N80钢的缓蚀能力。基于密度泛函理论，研究壳聚糖（CS）和CS-N-MB的反应活性，明确活性位点，并通过分子动力学计算缓蚀剂的吸附能以及体系中水分子的均方位移。结果 在15%盐酸环境中，CS-N-MB对N80钢具有良好的缓蚀作用，且当缓蚀剂添加量小于200mg/L时，随着浓度的增加，N80钢的腐蚀速率逐渐减小。当缓蚀剂添加量大于200 mg/L时，短时间内，随着浓度的增加，N80钢的腐蚀速率又略微增大，而72 h后N80钢的腐蚀速率略微减小并趋于稳定。电化学研究表明，CS-N-MB能够同时抑制腐蚀的阴极反应和阳极反应，是混合型缓蚀剂。分子模拟结果表明，CS-N-MB的主要活性位点集中在N、O以及环状结构处，且加入...

Preparation and Corrosion Inhibition of Piperazine Mannich Base Chitosan Corrosion Inhibitors

In order to solve the problem of acidification and corrosion of subsea oil production equipment, a green piperazine Mannich base chitosan derivative corrosion inhibitor CS-N-MB was synthesized in this paper, and its corrosion inhibition performance on N80 steel in 15wt.% hydrochloric acid solution was studied, and its mechanism of action on the metal surface was calculated. Using kojic acid and N-methylpiperazine as raw materials, Mannich base (MB) was synthesized through Mannich reaction, and then the Mannich base was grafted onto chitosan molecules. The synthesized products were characterized by infrared spectroscopy, and the corrosion inhibition ability of CS-N-MB on N80 steel in this strong acid environment was evaluated by electrochemical method and static weight loss method. The reactivity of chitosan (CS) and CS-N-MB was studied based on density functional theory, the active sites were clarified, and the adsorption energy of the corrosion inhibitor and the mean square displacement of water molecules in the system were calculated by molecular dynamics. The corrosion inhibition effect of N80 steel was good in the environment of 15 wt% hydrochloric acid, and when the corrosion inhibitor dosagewas less than 200 mg/L, the corrosion rate of N80 steel decreases gradually with the increase of concentration. When the addition of corrosion inhibitor was more than 200 mg/L, the corrosion rate of N80 steel increases slightly with the increase of concentration in a short time, but after 72 h, the corrosion rate of N80 steel decreases slightly and tends to be stable. Electrochemical studies showed that CS-N-MB can inhibit both cathodic and anodic reactions of corrosion simultaneously, and was a mixed inhibitor. Molecular simulation results show that the main active sites of CS-N-MB were concentrated in N, O and ring structures, and the movement of water molecules in the system was slowed down after adding CS-N-MB, which inhibits the occurrence of metal corrosion. CS-N-MB was a green corrosion inhibitor with good corrosion inhibition effect in strong acid environment. Multiple active centers can form a dense protective film on the metal surface, thereby effectively inhibiting the corrosion of metal.