曼尼希碱CO2盐水缓蚀剂的合成及其性能

Synthesis and Performance of Mannich Base CO2 Saline Corrosion Inhibitor

以水杨醛和二乙烯三胺为原料,合成了席夫碱中间体,并与甲醛和丙酮通过Mannich反应合成了含亚胺结构的曼尼希碱（ISMB）缓蚀剂。对ISMB结构采用红外和核磁进行了表征。通过静态失重法和电化学方法,考察了在质量分数为3%盐水（质量分数为3%的NaCl水溶液,下同）的饱和CO2水溶液中对N80钢片的缓蚀性能。通过TGA评价了ISMB缓蚀剂的耐高温性能。对缓蚀剂分子在碳钢表面的吸附行为、腐蚀形貌进行了考察,应用量子化学对ISMB的缓蚀机理进行了研究。结果表明：在70℃下,ISMB质量浓度为500 mg/L,腐蚀时间为72 h时,缓蚀剂的缓蚀率为90.4%。缓蚀剂自身在220℃以下时热稳定性良好,ISMB能自发吸附在钢片表面,且吸附类型是以化学吸附为主的混合吸附。通过原子力显微镜（AFM）观察N80钢片表面腐蚀形貌,结果表明：ISMB的缓蚀效果良好。通过量子化学得到全局反应活性参数,结果表明：ISMB分子能隙低,反应活性区域主要集中在苯环和氮氧原子。

A Schiff base intermediate was synthesized by using salicylaldehyde and diethylenetriamine as starting materials. Then, the Mannich reaction among Schiff base intermediate, formaldehyde and acetone led to a Mannich base （ISMB） corrosion inhibitor. The product was characterized by FTIR and 1HNMR. The corrosion inhibition performance of N80 steel sheet in 3% （mass fraction） saline water saturated by CO2 was investigated by static weight loss method and electrochemical methods. Its high temperature-resistance was also evaluated by thermogravimetric analysis （TGA）. The adsorption behavior and corrosion morphology of inhibitor on carbon steel surface were investigated. The inhibition mechanism of ISMB was discussed by quantum chemistry. The results showed that at 70℃, when the mass concentration of ISMB was 500 mg/L and the corrosion time was 72 h, the inhibition rate reached 90.4%. The inhibitor had an excellent thermal stability below 220℃. In addition, ISMB could spontaneously adsorb on the surface of steel sheet, and the adsorption process was a mixed model adsorption process and mainly a chemical adsorption process. The corrosion morphology of N80 steel sheet surface was observed by atomic force microscopy （AFM）. The results revealed that the corrosion inhibitor had quite satisfactory corrosion inhibition performances. The global reactivity parameters were obtained by quantum chemistry. It was found that the reactive region of low energy gap ISMB molecule was mainly concentrated on benzene ring, nitrogen atom and oxygen atom.