Inhibition of corrosion of Cu(II) in HNO3 using substituted hydroxytriazene

Inhibition effect of some hydroxytriazenes on copper in nitric acid medium has been studied using weight loss technique at temperature range between 303 to 343 K. The used hydroxytriazene compounds are 3-Hydroxy-3-phenyl-1-(4-sulphonato(sodium salt) phenyl) triazene(HPST), 3-Hydroxy-3-(3-methylphenyl)- 1-(4-sulphonato(sodium salt) phenyl) triazene(HMMPST), 3-Hydroxy-3-(4-methylphenyl)-1-(4-sulphonato (sodium salt) phenyl) triazene (HPMPST), 3-Hydroxy-3-(3-chloroplenyl-(4-sulphonato (sodiumsalt) phenyl) triazene (HMCPST), 3-Hydroxy-3-(4-chloroplenyl-(4-sulphonato (sodiumsalt)phenyl) triazene (HPCPST). Results reveal that inhibition efficiency increases with increasing concentration of hydroxytriazenes from 0.0005 to 0.002 M in following order HPMPST > HPST > HMMPST > HPCPST > HMCPST. HPMPST compound in 0.002M concentration show maximum inhibition efficiency of ~90 at % 303 K temperature. Effect of temperature on inhibition efficiency and thermodynamic parameters have also been reported. The adsorption of hydroxytriazenes obeyed Langmuir Adsorption Isotherm.