Synthesis And Properties Of Alkyl Triazole Corrosion Inhibitors

In the petrochemical, oil well acidizing and acid industrial operation process, acid medium can produce serious corrosion of the equipment. Adding corrosion inhibitors as a cheap and efficient means of corrosion inhibition has been widely applied in the actual production operation process. Triazoles corrosion inhibitor is one of the hot spots in the research of corrosion inhibitor both at home and abroad in recent years.However, the corrosion inhibition performance of long chain alkyl substituted triazole compounds in hydrochloric acid medium has not yet been reported, the corrosion inhibitor synthesis process is simple and high yield, the corrosion inhibitor is low toxicity, efficient and environmentally friendly, therefore, proceed from the angle of corrosion inhibitor molecular structure design, developed a series of green triazole corrosion inhibitors possess better adsorption and water-soluble ability with excellent corrosion inhibition efficiency is of great significance.Based on the above theory, this paper discussed the synthesis procedure of a series new type triazole corrosion inhibitors, using bromoalkane with three different length of carbon chain, trimethyl azide silane and propargyl alcohol as the main raw material, through the nucleophilic and substitution dipole cycloaddition reaction, N, N-dimethyl formamide was used as the main solvent, successfully synthesized three triazole corrosion inhibitors with three different length of carbon chain, fetch reaction yield as the main index, the single factor method is adopted to the synthesis process optimization include reaction raw material ratio, reaction temperature and reaction time, the determined optimum synthesis conditions of alkyl triazole are as follows:the first step is the nucleophilic substitution reaction, the mole ratio of reactant amount (trimethyl azide silane:alkyl bromine) is1:1.3, the reaction temperature is80℃, reaction time is20h, the second step is the dipole cycloaddition reaction, optimum reaction mole ratio (azide alkanes:propiolic alcohol) is1:1.2, the reaction temperature was50℃, the reaction time is7h, the target product yield is higher than95%. The product’s chemical structure is confirmed by elemental analysis, infrared spectrum(FT-IR) and1H NMR method. The study of corrosion inhibition efficiency of the target products is carried out using weight-loss method, electrochemical impedance spectroscopy (EIS) and Talfel polarization curve method. The adsorption mechanism of the target product has been discussed in a preliminary way.Weight loss results show that the triazole and compound corrosion inhibitors in20%hydrochloric acid for N80steel has excellent corrosion inhibition efficiency. The corrosion inhibition efficiency of three different corrosion inhibitors is proportional to the corrosion inhibitor dosage. When the addition amount is300mg/L, the corrosion rate reached99%. Under the condition of low temperature, the longer the carbon chain the higher inhibition efficiency can be achieved, and under the condition of high temperature, corrosion inhibitor with shorter length of carbon chain is more effective. When achieve the same inhibition efficiency, the compound inhibitor can effectively reduce the dosage of the main agent, thus reduce the cost of corrosion inhibitor. The compound inhibitor has better corrosion inhibitor performance relative to the single product under the condition of high temperature. Tafel polarization curve measurement results showed that the triazole corrosion inhibitor belongs to cathode inhibitor and the inhibition efficiency increased with the increase of carbon chain length, and decreased the corrosion current, caused a corrosion potential negative shift as well. Ac impedance test results show that join inhibitor can significantly increase the charge transfer resistance Rct, suppressed the corrosion, the higher the concentration of corrosion inhibitor, the bigger the charge transfer resistance Rct, result in smaller electric double layer capacitance Cdl, the decrease of electric double layer capacitance Cdi molecular adsorption is mainly due to the corrosion inhibitor molecule adsorb onto the carbon steel surface which reduces the dielectric constant. Isothermal adsorption results showed that the adsorption of triazole compound on the surface of N80steel obey the Langmuir adsorption isotherm.