甲叉膦酸类缓蚀剂缓蚀机理的量子化学研究

Quantum chemistry studies on the corrosion inhibition mechanism of methylene phosphonic acid

运用密度泛函论(DFT),在B3LYP/6-31G*水平上,计算氨基三亚甲基膦酸(ATMP)、甲胺二亚甲基膦酸(MADMP)、乙二胺四亚甲基膦酸(EDTMP)及己二胺四亚甲基膦酸(HDTMP)等4种甲叉膦酸类缓蚀剂分子的前线轨道能量、最高占有轨道、最低空轨道的组成及N、O、P杂原子的自然电荷分布、亲核Fukui指数和亲电Fukui指数。结果,这4种甲叉膦酸的缓蚀性能与其分子的能级间隙△E密切相关,△E越小,其缓蚀性能越好。其次,通过分析分子最高占有轨道、最低空轨道的组成及原子的Fukui指数,探讨此类缓蚀剂分子的反应活性位点,发现这4种甲叉膦酸是通过N、O及P原子与金属形成配位键及反馈配位键而具有缓蚀效果。为判断缓蚀剂性能的优劣,合成新型、高效的缓蚀剂及研究药剂间的协同效应提供理论指导。

Some quantum chemical parameters（front line orbital energy,composi tion of the highest occupied molecular orbital,the lowest unoccupied molecular orbital,natural charge of nitrogen atom,oxygen atom,phosphorus atom,nucleophilic fukui indice,electrophilic fukui indice） of amino trimethylene phosphonic acid（ATMP）,methylamine methylene phosphonic acid（MADMP）,ethylenediamine tetramethylene phosphonic acid（EDTMP） and hexanediamine tetramethylene phosphonic acid（HDTMP） were obtained at B3LYP/6-31G＊ level by means of Density Functional Theory（DFT） methods.It is found that the rates of methylene phosphonic acids have a certain relation to the energy gap（△E）.The smaller the energy gap,the better corrosion performance.Secondly,the reaction active sites were also discussed by analysising composition of the highest occupied molecular orbital,the lowest unoccupied molecular orbital and fukui indice of atoms.It is found that corrosion perfor mance of the four corrosion inhibitors was reached by N,O and P atoms and the metal coordination bond formation and feedback coordination bond.It provides theoretical guidance to judging the performance of corrosion inhibitors,to synthesizing new,highly effective corrosion inhibitors,to studying the synergistic effect of water treatment agents.