Performance Variation of Quaternary Amine Corrosion Inhibitors as a Function of Hydrocarbon Chain Length with Respect to Temperature

SPE International Conference on Oilfield Chemistry

Renzhuo

et al. 2019

A novel indolizine derivative inhibitor for acidization was introduced. It could exhibit effective corrosion inhibition at a much lower concentration without propargyl alcohol and shows economic and environmental advantages. From quinoline, benzyl chloride, and chloroacetic acid, two indolizine derivatives were prepared under certain conditions. These inhibitive indolizine derivatives were both synthesised from benzyl quinoline chloride (BQC), which one of the conventional quaternary ammonium corrosion inhibitors used for acidising. The target compound was purified and instrumental analysis methods including elemental analysis, high-resolution mass spectrometry (HRMS), and NMR were used to characterise the chemical structure. The inhibition performance of the indolizine derivatives in 15 wt.% HCl, 20 wt.% HCl, and mud acid (12%HCl + 3%HF) for N80 steel was investigated by weight loss measurement, electrochemical method (potentiodynamic polarization and EIS), and SEM surface morphology assessment. When 0.1 wt.% indolizine derivative was added, the inhibition efficiency of N80 steel in 15 wt.% HCl at 90 °C increased to 98.8 % and 99.1 % respectively without the synergistic effect of propargyl alcohol: however, in terms of BQC, even at a dosage of 1.0 wt.%, the inhibition efficiency of N80 steel only reached 83.3 % under the same conditions. The novel derivative could impart an improved corrosion resistance effect. Compared with BQC, there are more active adsorption sites in the derivative and therefore the inhibitor could be better fastened to the steel surface. The firmly adsorbed inhibitors would thereby prevent the metal surface from making contact with H+ ions and finally increase the inhibitory effect. As a high-efficiency corrosion inhibitor, the novel indolizine derivatives may offer a new strategy for corrosion protection in acidising.

High-efficiency Corrosion Inhibitor for Acidizing: Synthesis, Characterization and Anti-corrosion Performance of Novel Indolizine Derivative

Wang

SPE International Conference on Oilfield Chemistry

Renzhuo

et al. 2019

Dimer Indolizine Derivatives of Quaternary Salt Corrosion Inhibitors: Enlightened High-Effective Choice for Corrosion Prevention of Steel in Acidizing

SPE Production &Amp; Operations

Wang

Finšgar

et al. 2020

Summary For decades, increasingly severe downhole conditions call for superior and less-expensive corrosion inhibitors (CIs) for acidizing in petroleum production. Inhibitors that exhibit satisfactory protective ability at relatively low concentration are of great interest to most scholars in this area. In this work, two newly obtained dimer indolizine derivatives that were derived from the conventional quaternary quinolinium salts were introduced as potential highly efficient acidizing CIs. The indolizine derivatives could perform well alone, even without any synergistic component, in concentrated hydrochloric acid (HCl). Two quinoline ammonium salts, ethyl acetate quinolinium chloride (EAQC) and n-butyl quinolinium chloride (BuQC), were synthesized in advance by means of the quaternarization process. Afterward, in the presence of alkali, the ammonium salts could then get converted into the corresponding novel dimer indolizine derivatives easily by means of a 1,3-dipolar cycloaddition reaction in a relatively high yield. The derivatives were purified and their accurate chemical structures were confirmed by elementary analysis, nuclear magnetic resonance (NMR), and mass spectrometry (MS). Dimer derivatives of two quinoline salts were prepared successfully and characterized separately as C26H23N2O4Cl and C26H27N2Cl. Corrosion-inhibition performance of the quaternary quinoline salts as well as the related dimer indolizine derivatives in concentrated HCl for N80 steel was investigated by gravimetric research, electrochemical method, and scanning electron microscopy (SEM) energy dispersive X-ray analysis. The thermodynamic aspect of the inhibition was also discussed. The structure of EAQC and BuQC are very close to the quinolinium salt inhibitors that are commonly used as key components in commercially accessible acid CI products. However, under alkaline condition, EAQC and BuQC would easily be transformed to dimer indolizine derivatives that possess a general “indolizine” structure. That is the reason why the targeted molecules are recognized as “dimer indolizine derivatives.” Both the derivatives have good thermal stability at approximately 248°F and are easily soluble in acid solution. The surprising difference in the anticorrosion effect between the original quinoline salts and their dimer derivatives was proved by weight-loss experiments in 15 wt% HCl at 194 and 248°F with dosage ranges from 0.01 to 0.5 wt%. The derivatives could retard the corrosion of steel considerably at a much lower concentration compared with their precursors. A 0.1-wt% dosage of indolizine derivatives could increase the inhibition efficiency (IE) of N80 steel remarkably, to approximately 99.0% in 15 wt% HCl at 194°F. Results obtained from gravimetric tests and electrochemical methods are in good agreement and confirmed the well-behaved inhibition of the derivatives. We predict that the inhibition will be enhanced apparently when similar quinoline or pyridine ammonium salt are converted via the similar 1,3-dipolar cycloaddition mechanism. We have determined that the use of dimer indolizine derivatives provides a creative new choice for low-cost corrosion prevention, and the protective compounds can be applied as main component of acidizing CIs in the coming years.

Novel High-Effective Component for Acidizing Corrosion Inhibitors: Indolizine Derivatives of the Quaternary Quinolinium Salts

SPE Asia Pacific Oil &Amp; Gas Conference and Exhibition

Yefei

Finšgar

et al. 2020

Acidizing is a widely used method for the well stimulation and Corrosion inhibitors (CIs) are essential in acidizing fluid to mitigate corrosion of metallic equipment. This calls for high-effective CIs as the demands for oil and gas still increases. This paper introduces several new protective indolizine derivative compounds with remarkable inhibition effectiveness under high-temperature acidizing condition. The indolizine derivatives were obtained facilely through the cycloaddition (at about 80 °C, alcohol as a solvent) procedure from the conventional quinolinium salt. Chemical structures of the derivatives were confirmed by instrumental analysis methods including NMR, MS etc. The corrosion inhibition properties of the indolizine derivatives were investigated and evaluated by weight loss test, electrochemical methods (Tafel curve and EIS), in comparison with their quaternary quinolinium precursors. Corrosion inhibition behavior of the derivatives in acid was simulated by DFT study. The thermodynamic aspect of the inhibition were also investigated. Experimental results showed that very low dosage of indolizine derivatives exhibit excellent inhibition efficiencies for the N80 steel in corrosive medium. Apart from the good solubility and thermo-stability in aqueous acid solution, the indolizine derivatives even showed eco-friendly advantages by presenting a much lower EC50 values than the other CIs. Compared with the conventional acidizing CIs, the composite indolizine derivative derived inhibitor mixture can dramatically mitigate the corrosion even at low amount of the mixture added, especially for those tests conducted at the bottom-hole elevated temperatures. The amazing inhibition of novel indolizine derivative with organic or inorganic components reveals that the mixture could be utilized as new effective CI for acidizing in concentrated hot acid. The inhibition of series traditional quinolinium salts would get greatly improved after they have get converted into the corresponding indolizine derivative inhibitors, which provides enlightening thoughts for developing novel high-effective CIs. The use of these compounds may offer a creative new choice for strong acid medium corrosion in petroleum engineering and showing good prospects in replacement of the current main components of acidizing CIs in the near future.