Synthesis And Performance Evaluation Of Imidazoline Type Corrosion Inhibitors

CO2 and other corrosive gases that causing serious corrosion and hazards for the equipments were included in the oil and gas field production.By studaying the characteristics of CO2 corrosion and and high salinity of oil gas fields produced fluid, The imidazoline corrosion inhibitors has been synthesized for controling CO2 corrosion effectively in this paper. It has been found that the imidazoline intermediate can be directly used in the crude oil to inhibit corrosion of carbon steel through experiments. And the imidazoline quaternary can be used in the simulant gas water to inhibit CO2 corrosion. The main work was as follows:Palmitic acid and tetraethylenepentamine were the raw materials of the reaction reacted by using the method of solvent,and its final product was the imidazoline intermediate.Using orthogonal experiments and electrochemistry polarization curve to select the reaction conditions of the imidazoline intermediate initially. So the initial conditions can be got.The temperature of acylation reaction was at 165?.The time of acylation reaction was 3h.The proportion of acid and amine was 1:1.1. The temperature of cyclization was at 220?. By using single factor variable method and the weight loss test method to select the optimal reaction conditions. The optimal reaction conditions were as follow:the temperature of acylation reaction was at 165?.The time of acylation reaction was 4h.The proportion of acid and amine was 1:1.3. The temperature of cyclization was at 220?.These reaction conditions as the final synthesis conditions. Then capric acid,stearic acid, cinnamic acid,erucic acid and tetraethylenepentamine were synthesized four kinds of imidazoline intermediate. The molecular structure of five kinds of imidazoline intermediate were analyzed by IR.And through the method of electrochemistry polarization curve to compare the performance of intermediates.It turns out that palmitic acid was the best selection. And intermediate were analyzed by 1HNMR.And four kands of quaternary were synthesized with four kands of quaternization reagent. It turns out that the best quaternization reagent was benzyl chloride. By using single factor variable method to select the optimal quaternization reaction conditions were as follow:the proportion of intermediate and benzyl chloride was 1:1.1. The temperature of quaternization reaction was at 90?. The time of reaction was 4h.Finally, The molecular structure of imidazoline quaternary was analyzed by IR and 1HNMR.It turns out that imidazoline intermediate can be dissolved in the crude oil through experiment.So imidazoline intermediate can be used in the crude oil to control corrision.The inhibition rate of imidazoline intermediate was 80.94%.Through experiments to study the performance of imidazoline quaternary in the mock water includeing saturated CO2 gas at 50?.Its pH was 7.86.Its temperature of open flash was more than 80?.It has a good water-dispersible.Its emulsifying tendency was little. The best amount of corrosion inhibitor was 0.1%. The inhibition rate of imidazoline intermediate was 86.13%. The imidazoline quaternary conforms Langmuir isotherm equation.Through SEM to observe surface morphology of steel. And it can be found that inhibitor molecules adsorbed on the steel surface but uneven. Increasing Cl- concentration will weaken the adsorption of inhibitor molecules, so that the performance of corrosion inhibitor was reduced. And as the temperature increased, the the performance of corrosion inhibitor was reduced.Finally,it through experiments to study the performance of corrosion inhibitor compelx with thiourea,anhydrous sodium sulfate,potassium phosphate monobasic,bromohexadecyl pyridine, hexamethylenetetramine, iso-propyl alcohol,OP-10, CPI-W. CPI-W was the best selection found in the experiment through the weight loss test method in the mock water including saturated CO2 gas.