3-[(4-amino-2-methyl-5-pyrimidinyl) methyl]-5-(2-hydroxyethyl)-4-methyl thiazolium chloride hydrochloride as green corrosion inhibitor of copper in HNO3 solution and its adsorption characteristics

The inhibitory effect of 3-[(4-amino-2-methyl-5-pyrimidinyl) methyl]-5-(2-hydroxyethyl)-4-methyl thiazolium chloride hydrochloride (thiamine hydrochloride) or vitamin B-1 hydrochloride on acid corrosion of copper in 2.5 M nitric acid (HNO3) solution was investigated using a weight loss method. Thiamine hydrochloride inhibited the corrosion of copper in 2.5 M HNO3 solutions. The inhibition efficiency increased with increasing concentration of thiamine hydrochloride but decreased with increasing exposure. Adsorption of thiamine hydrochloride molecules on copper surface was found to obey Langmuir adsorption isotherm with standard free energy of adsorption (Delta G(ad)(o)) -30.55 kJ mol(-1). The inhibition mechanism was characterized from trends of inhibition efficiency, thermodynamic, and kinetic parameters.