Study On The Synthsis Naphthenate Imidazoline Borates And Corrosion Inhibition Performance

Firstly the mid-pruduct imidazoline was produced by reaction of naphthenic acid and Hydroxyethyl-ethylenediamine.Then with Toluene being the carrying agent, Naphthenate imidazoline borates(NIB) was synthesized from the intermediate and Boric acid. Weight method and electrochemical polarization curves were used to evaluated the corrosion inhibition performance of NIB for metals in HCl and H2S solution and hydrochloric acid,sulfate,phosphate.In the process of the synthesis,the method of singer factor of multi-level was used in order to get the optimum reaction condition,and the optimum reaction condition was got through tests:the ratio of imidazoline to Boric acid is 1:1.2,the maximum temperature is about 190-200℃,the reaction time is about 5h.the amount of toluene is 30% of reactant mass.The inhibition efficency is increasing as the concentration of NIB increase in the HCl and H2S solution. As the pH of the solution decreased, the inhibition effeet increased at first and then decreased. When the pH value of solution is acidic, the inhibition effect was better obviously than in alkaline solution. Corrosion inhibition rate decreased with the increase of the concentration of H2S, When the concentration of H2S reached a certain value, the corrosion inhibition rate was almost not change.the result showed that the corrosion inhibition rate on mild steel,aluminum coupon,stainless steel was high.The inhibition efficency inereased as the concentration of inhibitor increased. When the concentration of inhibitor reached a certain value, the corrosion inhibition rate was almost not change. The results obtained from electrochemical polarization are consistent with the results obtained form weight loss. Experiments in the phosphate shows that when the concentration of inhibitor increased, the corrosion inhibition rate increased in first and then decreased. There was an optimal dose of inhibitors;The experiments in sulfate show that: The inhibitor can inhibit the corrosion of carbon steel greatly, when the dosage is 300g / L, the corrosion inhibition rate was highest, and the surface was bright . Higher inhibition efficiency can be obtained with a small dose of inhibitor in exprements of stainless steel. The corrosion inhibition performance of NIB became better in first and then worse as the exprement tempreture rised, the corrosion inhibition rate inereased and then decreased when the experiment time extended.