Synthesis And Property Evaluation Of High Temperature Acidification Corrosion Inhibitor

At present,most of the high-temperature corrosion inhibitors used in the field of oil reservoir reconstruction have some shortcomings such as poor solubility,coking easily.And the high-temperature acidification corrosion inhibitors used widely are mainly acetylenic alcohols inhibitors.Although alkyne alcohols can improve greatly the corrosion resistance of corrosion inhibitors,but it is expensive and highly toxic.Thus,the corrosion inhibitors with good solubility,more adsorption center and less toxicity have broad application prospect.In recent years,diquaternary ammonium salts with the above advantages have aroused great interest in the field of corrosion protection.In this paper,nine symmetrical diquaternary ammonium salts were prepared by quaternization of quinolone,pyridine,?-methylpyridine with 1,4-dibromobutane,1,6-dibromohexane,1,8-dibromooctane,respectively.The synthesized compounds were characterized using NMR and FTIR.And their inhibition performances for N80 steel in 15% HCl solution were investigated by weight loss measurements.The results indicated that quinoline diquaternary ammonium salts had better inhibition performances than pyridine diquaternary ammonium salts and ?-methylpyridine diquaternary ammonium salts.And for the same series productions,the protection for N80 steel increased gradually with the increase of the length of hydrophobic chain.1,8-octane-bis-(quinoidine bromide)had the best corrosion inhibition performances.To further improve the inhibition efficiency,a new synergistic inhibitor QC-8 was prepared from 1,8-octane-bis-(quinoidine bromide)(Q-8-Q)and cinnamaldehyde(CA).Through the optimization experiment,the best synergistic ratio was obtained.Its inhibition efficiency for N80 steel in 15% HCl solution were systematically investigated on the basis of weight loss,electrochemical test and surface analysis.At the same time,the effects of the temperature and inhibitor dose on the inhibition efficiency were also discussed.The results of electrochemical test indicated that QC-8 was a mixed type inhibitor mainly to inhibit the cathodic reaction.A protective film was formed on the surface of N80 steel to inhibit the corrosion reaction.After 4 h of immersion in 15% HCl at 90?,the inhibition efficiency of QC-8 could reach up to 99.5% at the concentration of 5×10-3M,which could confirm that QC-8 had excellent corrosion inhibition for metal in acid medium.Hydroxyl is effective adsorption center,so it can promote the inhibiton effect of corrosion inhibitor.In this paper,three diquaternary ammonium salts containing hydroxyl named 1,3-bis-(quinoidine chloride)-2-propanol,1,3-bis-(pyridine chloride)-2-propanol,1,3-bis-(?-methylpyridine chloride)-2-propanol were synthesized.The synthesized compounds were characterized by NMR and IR spectrum.The effects of various factors on the inhibition efficiency were investigated.The experimental results showed the existence of hydroxyl largely improved the performance of the corrosion inhibitor.The synthesized diquaternary ammonium salts containing hydroxyl belonged to mixed type organic corrosion inhibitors,which could form a protective film on metal surface to inhibit the corrosion reaction through adsorption.The inhibition mechanism on the N80 steel surface was best fitted by Langmuir adsorption mode,including both physical sorption and chemical sorption process.