The corrosion inhibitor studied hexa methylene diamine tetra methyl-phosphonic acid (HMDTMP) was synthesized by the micro-wave technique. The obtained product is purified and characterized by 1H NMR, 13C NMR, 31P NMR and IR spec- troscopic methods. The molecular structure is shown in Fig. 1.
The aggressive solutions made of AR grade 37% HCl. Appropriate concentrations of acid were prepared using dou- ble distilled water. The inhibitors were added to freshly pre- pared 0.5M HCl in the concentration range of 5·10