膦酰基羧酸调聚物缓蚀性能的量子化学研究

Quantum chemistry study of corrosion inhibition performance of phosphono carboxylic acid telomer

研究中发现膦酰基羧酸调聚物(POCA)对碳钢的缓蚀作用良好,而丙烯酸与2-丙烯酰胺-2-甲基丙基磺酸的共聚物(AA- AMPS共聚物)则几乎无缓蚀作用。量子化学方法计算表明POCA调聚物的前线HOMO分子轨道能量较AA-AMPS共聚物大,所以POCA更容易为铁的空d轨道提供电子;AA-AMPS共聚物中对HOMO轨道电荷密度贡献较大的主要是AMPS分子中酰胺基团的N和O原子,O原子的电子轨道布居数虽然较大,但贡献却比N原子小(10%左右),而N原子贡献虽然较大(75%左右),但电子轨道布居数小,因此很难在酰胺基团处与金属吸附。POCA分子中膦酰基基团的P原子和O原子对HOMO轨道电荷密度贡献分别达到70%和20%,且其轨道电子布居数较大,因此较容易通过膦酰基与金属配位吸附而缓蚀性能良好。POCA的缓蚀功能由引入链分子中的膦酰基基团获得,羧酸基团和磺酸基团基本无作用。

The lab study shows Phosphono carboxylic acid telomer（POCA） has good corrosion inhibition effect on mild steel but AA- AMPS copolymer has no effect. The quantum chemistry calculations indicate that the HOMO orbital energies of POCA telomer are higher than AA-AMPS copolymer＇ s which mean POCA can offer electron more easily to empty d orbital of metal iron. The N and O atoms of amide groups of AA-AMPS copolymer have more contribution to the density of the electronic charge in HOMO orbital, but it is difficult to form absorb site between amide group and metal because O atom has bigger electron gross orbital population and less contribution （about 10% ） to the density of the electronic charge whereas N atom is reverse（about 75% ）. The contribution to the density of the electronic charge in HOMO orbital of P and O of phosphono group is differently 70% and 20% and the electron gross orbital population is bigger, so it has good corrosion inhibition effect result from the coordination adsorption. The corrosion inhibition performance of POCA is gained by phosphono group, carboxylic acid groups and sulfonic acid groups have no contribution to corrosion inhibition.