Imidazoline Sulfate Salt Synthesis And Performance Research

Acid treatment used in oilfield can increase the permeability of reservoir, improving oil production and development effect of oilfield, so it’s widely used as a plugging removal and yield-increased measure. But different kinds or concentrations of acidification liquid system used in oilfield(hydrochloric acid, hydrofluoric acid, mud acid which is mix by hydrochloric acid and hydrofluoric acid in proportion, and fluoroboric acid) may cause serious corrosion to acidizing units and pipeline as acid treatment is executed through high-pressure pump truck and pipelines connecting wellhead on well sites. To avoid corrosion accidents of acid treatments, corrosion must be solved in the process of acid treatment and plugging removal.Organic heterocyclic compound and quaternary ammonium salt may easily be absorbed to metal surface and overlap to be a membrane, restraining metal’s corrosion process, so these are of good corrosion inhibition property, and are wildly used in metal corrosion protection area. Imidazoline is a kind of corrosion inhibitor with excellent performance that arise in recent decades. Because of its advantages (low-level toxicity, innocuity, good stability and simple structure), Imidazoline corrosion inhibitor is largely used in various areas of crude oil production.Therefore, in consideration of designing inhibitor molecule, by combine imidazoline heterocyclic ring with sulfuric ester, developing a new type of imidazoline corrosion inhibitor which has good water solubility and good corrosion inhibition. Use the corrosion inhibitor above as the main agent, complex with propargyl alcohol and OP-10, then a new highly efficient, fine dispersion acidification inhibitor can be obtained.The synthesis of target product is divided into tow steps:The first step is using oleic acid and N-(2-hydroxyethyl) ethylene diamine as raw materials and dimethylbenzene as azeotropic agent to synthesize1-hydroxyethyl-2-oleic acid imidazoline. The second step is the quaternary ammoniation of1-hydroxyethyl-2-oleic acid imidazoline, during which aminosulfonic acid is used as quaternization agentia. The process is the reaction of1-hydroxyethyl-2-oleic acid imidazoline and aminosulfonic acid with urea as catalyzator, and then1-hydroxyethyl-2-oleic acid imidazoline sulfuric ester is obtained.When discussing synthesis optimum conditions of the tow compounds in this paper, L16(4(?)5) and L9(3(?)4) orthogonal array were used to arrange experiments. Then the results were input into the adjusted orthogonal experimenal tables, and these results were analyzed respectively to get the orthogonal experiment variances, thus the optimization of experimental conditions can be deduced.In this paper, infrared spectrums was adopted to to characterize structures of target compound (1-hydroxyethyl-2-oleic acid imidazoline sulfuric ester) and the intermediate(1-hydroxyethyl-2-oleic acid imidazoline). The results indicate that the target compound and intermediate are in conformity with their theory structures. It is proved that the synthetic product is the target product which is needed.In this thesis, the corrosion inhibition about the intermediate (HEAI) and the target product (ISES) in hydrochloric acid medium have been discussed by static weight loss method. This article also discussed the impact about the inhibitor concentration, corrosion temperature and acid concentration on the corrosion performance.There are two inhibitor complex systems which have been studied by weight loss method in this thesis too. The first one is made up of HEAI and BCC, and the second one is made up of ISES and BCC. Both of the two systems’inhibition performance are the best when the concentration of HEAI—BCC is100mg/L-100mg/L and the concentration of ISES-BCC is50mg/L-150mg/L respectively. Based on the inhibitor complex system, synergized action is also studied with adding OP-10surfactant into the inhibitor complex system. In the hydrochloric acid, when the concentration of OP-10is30mg/L, the synergistic effect to the first system achieve the best, then continue increasing the concentration, the effect decreased slightly. So it is with the second system when the concentration of OP-10is20mg/L. Thus, the optimal ternary complex system for HEAI-BCC-OP-10is100-100-30mg/L, and the optimal one for ISES-BCC-OP-10is50-150-20mg/L.Choose N80steel as working eletrode, the corrosion medium is15%hydrochloric acid and the temperature is50℃. The protective ability of the inhibitors (HEAI, ISES, and their complex system with propargyl alcohol and OP-10in corrosive solutions) are investigated by potentiodynamic polarization spectroscopy curves (Tafel curves) and electrochemical impedance spectrum (EIS) methods. The Tafel curves are measured by CS300and the electrochemical impedance spectrum are measured by CHI660C electrochemical workstation. The EIS shows that the equivalent electric circuit belongs to Rs(LRL)(CPERt), the capacitive reactance increases along with the increase of corrosion inhibitor concentration. The electrochemical kinetics parameters are analyzed by different softwares. According to the formula of inhibitory efficiency, the inhibiting rate can be obtained.In this thesis, the inhibition mechanism of the imidazoline was discussed. The research of corrosion mechanism reflects that HEAI and ISES belong to the mixed corrosion inhibitor. The absorption of ISES on the steel surface conforms to Langmuir absorption at constant temperature formula.This thesis also investigate cooperative mechanism about ISES with propargyl alcohol in the acid medium and the synergistic mechanism with surfactant OP-10.