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

摘要:

以水杨醛和二乙烯三胺为原料，合成席夫碱中间体，其与甲醛和丙酮通过Mannich反应合成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%盐水的饱和CO2水溶液中对N80钢片的缓蚀性能。通过热重分析（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的缓蚀机理进行了计算。结果表明：在70℃下，ISMB质量浓度为500 mg/L，腐蚀时间为72h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，合成缓蚀剂的缓蚀效果良好。最后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。

Abstract:

Synthesis of Schiff base intermediates using salicylaldehyde and diethylenetriamine as starting materials. After that, the Schiff base intermediate was supposed to react with formaldehyde and acetone, which would synthesize Mannich base (ISMB) corrosion inhibitor containing the imine by Mannich reaction. The structure of the product was determined by FTIR and 1H-NMR spectroscopic methods. The corrosion inhibition performance of N80 steel sheet in mass fraction of 3% saline water saturated by CO2 was investigated by static weight loss method and electrochemical methods. The corrosion inhibitor was also evaluated by thermogravimetric analysis (TGA) to investigate its resistance to high temperature. The adsorption behavior and corrosion morphology of the inhibitor molecules on carbon steel surface were investigated. The inhibition mechanism of ISMB was calculated by quantum chemistry. The resoults show that, at 70℃, when the dosage of corrosion inhibitor reached 500 mg/L and the corrosion time was 72h, the inhibition rate of the corrosion inhibitor is 90.4%. The inhibitor had an excellent thermal stability in below 220℃, ISMB can be spontaneously adsorbed on the surface of steel sheet, and the adsorption type is a chemical adsorption based mixed adsorption. The corrosion morphology of N80 steel sheet surface was observed by atomic force microscopy (AFM). The results showed that the corrosion inhibition performance of corrosion inhibitor was quite satisfactory. Finally, the global reactivity parameters were obtained by quantum chemistry. The results showed that the energy gap of ISMB molecules was low, and the reactive region was mainly concentrated on benzene ring, nitrogen atom and oxygen atom.