Thiamine Hydrochloride as Copper Corrosion Inhibitor in 1M HNO3

3-((4-Amino-2-methyl-5-pyrimidinyl) methyl)-5-(2-hydroxyethyl)-4-methylthiazolium chloride hydrochloride also known as Thiamine hydrochloride (Vitamin B1 hydrochloride) was used as copper corrosion inhibitor in 1.0M HNO3 solution. The study was performed using weight loss and Density Functional Theory (DFT) methods. Copper dissolution was found to be temperature and Thiamine concentration dependent. The thermodynamic functions related to the adsorption of the molecule on the copper surface and that of the metal dissolution were determined. The results show a spontaneous adsorption and an endothermic dissolution processes. Adsorption models, including Langmuir, El-Awady and Flory-Huggins isotherms were examined. The Dubinin Raduskhevich isotherm was used to distinguish between physisorption and chemisorption. Furthermore, the global and local reactivity parameters of the molecule were analysed. Experimental and theoretical results were found to be in good agreement.