本文選題：緩蝕劑 + 曼尼希堿��； 參考：《陜西科技大學》2017年碩士論文

【摘要】：金屬的腐蝕問題已經(jīng)成為一個嚴重的社會問題,不僅造成了大量的經(jīng)濟損失,更帶來了巨大的安全隱患。使用緩蝕劑是減緩金屬腐蝕的有效手段。曼尼希堿緩蝕劑由于較好的穩(wěn)定性和分散性、低毒高效等,而受到廣泛應用。但是,目前使用的緩蝕劑大多有添加量較大,在高酸度條件下緩蝕效果不明顯等缺點。曼尼希堿中含有氮、氧等雜原子,這些雜原子中都有未被共用的孤對電子,可以進入金屬原子的空軌道,在金屬表面形成吸附。本課題為了制備緩蝕性能較好的緩蝕劑,依據(jù)緩蝕劑緩蝕機理,選取曼尼希反應需要的醛、酮、胺,對它們進行相互組合反應,測定所得產(chǎn)物緩蝕效率。實驗結果表明以甲醛、鄰甲苯胺、芐叉丙酮為反應物和以甲醛、鄰甲苯胺、對甲氧基苯乙酮為反應物所制備的緩蝕劑緩蝕效率較高,分別命名為MNX-A和MNX-B。通過單因素實驗和正交實驗考察了反應溫度、反應時間、反應pH、醛酮胺摩爾比對緩蝕劑緩蝕效率的影響,篩選緩蝕劑MNX-A和MNX-B的最佳制備條件。緩蝕劑MNX-A的最佳制備條件為反應溫度70℃、反應時間2h、反應pH為3、醛酮胺摩爾比為1:1:1,此條件下緩蝕劑對N80鋼的緩蝕效率為93.95%,分離產(chǎn)率為83.14%。MNX-B的最佳制備條件為反應溫度60℃、反應時間3h、反應pH為2、醛酮胺摩爾比為1:1:1,此條件下緩蝕劑對N80鋼的緩蝕效率為92.45%,分離產(chǎn)率為86.34%。借助核磁共振確定了MNX-A和MNX-B的主產(chǎn)物的結構,與目標產(chǎn)物一致。通過掛片失重法,測定了緩蝕劑的緩蝕效率隨腐蝕溫度、腐蝕時間、鹽酸濃度、緩蝕劑濃度的變化。緩蝕劑MNX-A和MNX-B的緩蝕效率隨腐蝕溫度的升高和鹽酸濃度的增大,先增大后減小;隨緩蝕劑濃度的升高和腐蝕時間的延長,先增大后基本不變;在N80鋼表面的吸附都符合Langmuir等溫吸附模型,吸附ΔG0分別為-33.49kJ/mol和-32.64k J/mol,都位于-20kJ/mol~-40kJ/mol之間,表明緩蝕劑在金屬表面既有化學吸附又有物理吸附。分散性實驗表明,在測定條件下緩蝕劑濃度低于1500mg/L時,緩蝕劑分散性良好。通過極化曲線分析可知緩蝕劑MNX-A和MNX-B腐蝕電位位移都小于85mV,表明為陰極抑制為主的混合型緩蝕劑;依據(jù)腐蝕電流密度計算出的緩蝕效率與掛片失重法得到的緩蝕效率基本一致。通過分析交流阻抗圖,模擬出緩蝕劑在鹽酸溶液中的電路圖,分析溶液中緩蝕劑分布狀態(tài),推測緩蝕機理。通過掃描電鏡觀察金屬表面形態(tài),發(fā)現(xiàn)添加緩蝕劑后,N80鋼表面的腐蝕得到了有效的控制。選取多種復配劑對緩蝕劑MNX-A和MNX-B進行復配,討論了在緩蝕劑添加量為10mg/L、20mg/L、50mg/L時,復配劑濃度對復合緩蝕劑緩蝕效率的影響。其中KI、六次甲基四胺、硫脲對MNX-A和MNX-B均表現(xiàn)出了良好的協(xié)同作用。鉬酸鈉在緩蝕劑濃度為20mg/L時表現(xiàn)出良好的協(xié)同作用。
[Abstract]:The corrosion of metals has become a serious social problem, which not only causes a lot of economic losses, but also brings huge hidden dangers to safety.The use of corrosion inhibitor is an effective way to reduce metal corrosion.Mannich base corrosion inhibitor is widely used because of its good stability and dispersion, low toxicity and high efficiency.However, most of the corrosion inhibitors used at present have some disadvantages, such as large amount of corrosion inhibitor and low inhibition effect under high acidity.There are nitrogen, oxygen and other hetero-atoms in Mannich base, all of which have unshared lone pairs of electrons, which can enter the empty orbit of metal atoms and form adsorption on metal surface.In order to prepare corrosion inhibitor with good corrosion inhibition performance, according to the corrosion inhibition mechanism of the inhibitor, the aldehyde, ketone and amine needed for Mannich reaction were selected, and the corrosion inhibition efficiency of the products was determined.The experimental results show that the corrosion inhibitor prepared with formaldehyde, o-toluidine, benzyl acetone as reactant, formaldehyde, o-toluidine and p-methoxyacetophenone as reactants has higher corrosion inhibition efficiency, and is named MNX-A and MNX-B, respectively.The effects of reaction temperature, reaction time, reaction pH, molar ratio of aldehyde, ketone and amine on the corrosion inhibition efficiency of corrosion inhibitor were investigated by single factor experiment and orthogonal experiment. The optimum preparation conditions of inhibitor MNX-A and MNX-B were selected.The optimum preparation conditions of corrosion inhibitor MNX-A were as follows: reaction temperature 70 鈩，

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