Synthesis and evaluation of some new cationic surfactants as corrosion inhibitors for carbon steel pipelines in oil and gas production "
Ahmed Hussien Ahmed Youssif;
Abstract
The work discusses the corrosion inhibition of carbon steel metal in 1M HCl solution and formation water by different synthesized cationic surfactants I(4N), II(4N) and IV(4N). In this work, the inhibition effects of those compounds have been studied by several experimental methods.
This work contains three chapters:
Chapter 1:"Introduction"
This chapter includes a general introduction about corrosion (definition, the economic cost, forms, factors, prevention and types of inhibitors) and surfactants (definition, classification and applications).
Chapter 2: "Materials and experimental techniques"
The experimental part includes complete description of chemicals used, preparation of solutions, metal composition, synthesis of cationic surfactants and description of their application as the following:
• Synthesis of new cationic surfactants
The desired cationic surfactants were synthesized through two main steps, the first step was formation of the main Schiff base by reaction N1,N1'-(ethane-1,2-diyl)bis(ethane-1,2-diamine) with isonicotinaldehyde while the second step was quaternization reaction of the prepared Schiff base with different number of dodecyl bromide compounds to obtain the desired cationic surfactants.
• Confirmation the chemical structure of prepared Schiff base and cationic surfactants using FTIR, 1HNMR and Mass spectroscopes.
• Evaluation the inhibition efficiency for the synthesized cationic surfactants as corrosion inhibitors for carbon steel pipelines in both 1M HCl solution and formation water by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques.
• Determination of activation and adsorption thermodynamic parameters of the cationic surfactants on the carbon steel surface in 1M HCl solution and formation water.
• Determination of synergistic effect between KI, ZnCl2 and the cationic surfactants in formation water.
• Determination of the surface parameters of the synthesized cationic surfactants.
Chapter 3: "Results and discussion"
This chapter included the following parts:-
1. Characterization of the synthesized Schiff bases:
The chemical structure of the synthesized cationic surfactants was confirmed by spectroscopy analysis include: FTIR, 1HNMR, and Mass Spectra.
2. Evaluating of the synthesized cationic surfactants as corrosion inhibitors for carbon steel in 1M HCl solution and formation water by
2.1. Weight loss measurements
The prepared compounds I(4N), II(4N) and IV(4N) were tested as corrosion inhibitors for carbon steel in 1M HCl solution at four different temperatures 25, 40, 55 and 70oC and in formation water at 25oC only. The data revealed that, the inhibition efficiency of the synthesized cationic surfactants increases with increasing the cationic surfactant concentration in both media, also it was found that inhibition efficiency decreases with increasing the temperature in 1M HCl.
Synergistic effect between KI, ZnCl2 and cationic surfactants in formation water was studied. The experimental data showed that, after adding various concentrations of KI and ZnCl2 to the cationic surfactants at 25 oC, the inhibition efficiency increases by increasing the concentration of inorganic salts. This behaviour indicating that, the synergism phenomenon exists between cationic surfactant and KI or ZnCl2 leading to increasing the inhibition efficiency
2.2. Potentiodynamic polarization measurements
The data indicated that:-
The presence of the synthesized cationic surfactants in both 1M HCl solution and formation water slightly shifted the corrosion potential (Ecorr) to both negative and positive directions. This indicates that the synthesized cationic surfactants acted as a mixed type inhibitor
For all synthesized cationic surfactants,(icorr) decreased whereas (ηp) increased with increasing the inhibitor concentration. This could be related to the adsorption of the inhibitor over the cathodic and anodic active corroded surface. The increase in corrosion inhibition efficiency of the studied surfactant indicated that the synthesized cationic surfactant had efficient inhibitive properties for the metal surface.
2.3. Electrochemical impedance spectroscopy (EIS)
In both 1M HCl solution and formation water, the data showed that the increase of charge transfer resistance (Rct) and decrease of the pseudo capacity, (Cdl), with increasing the inhibitor concentration indicated that, these compounds have the ability to inhibit the corrosion rate of carbon steel according to adsorption mechanism (formation of a surface film). It was found that the order of the inhibition efficiencies of the cationic surfactants decrease in the following arrangement:
IV(4N) > II(4N) > I(4N)
and these results were in good agreement with those obtained from weight loss and potentiodynamic polarization methods
This work contains three chapters:
Chapter 1:"Introduction"
This chapter includes a general introduction about corrosion (definition, the economic cost, forms, factors, prevention and types of inhibitors) and surfactants (definition, classification and applications).
Chapter 2: "Materials and experimental techniques"
The experimental part includes complete description of chemicals used, preparation of solutions, metal composition, synthesis of cationic surfactants and description of their application as the following:
• Synthesis of new cationic surfactants
The desired cationic surfactants were synthesized through two main steps, the first step was formation of the main Schiff base by reaction N1,N1'-(ethane-1,2-diyl)bis(ethane-1,2-diamine) with isonicotinaldehyde while the second step was quaternization reaction of the prepared Schiff base with different number of dodecyl bromide compounds to obtain the desired cationic surfactants.
• Confirmation the chemical structure of prepared Schiff base and cationic surfactants using FTIR, 1HNMR and Mass spectroscopes.
• Evaluation the inhibition efficiency for the synthesized cationic surfactants as corrosion inhibitors for carbon steel pipelines in both 1M HCl solution and formation water by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques.
• Determination of activation and adsorption thermodynamic parameters of the cationic surfactants on the carbon steel surface in 1M HCl solution and formation water.
• Determination of synergistic effect between KI, ZnCl2 and the cationic surfactants in formation water.
• Determination of the surface parameters of the synthesized cationic surfactants.
Chapter 3: "Results and discussion"
This chapter included the following parts:-
1. Characterization of the synthesized Schiff bases:
The chemical structure of the synthesized cationic surfactants was confirmed by spectroscopy analysis include: FTIR, 1HNMR, and Mass Spectra.
2. Evaluating of the synthesized cationic surfactants as corrosion inhibitors for carbon steel in 1M HCl solution and formation water by
2.1. Weight loss measurements
The prepared compounds I(4N), II(4N) and IV(4N) were tested as corrosion inhibitors for carbon steel in 1M HCl solution at four different temperatures 25, 40, 55 and 70oC and in formation water at 25oC only. The data revealed that, the inhibition efficiency of the synthesized cationic surfactants increases with increasing the cationic surfactant concentration in both media, also it was found that inhibition efficiency decreases with increasing the temperature in 1M HCl.
Synergistic effect between KI, ZnCl2 and cationic surfactants in formation water was studied. The experimental data showed that, after adding various concentrations of KI and ZnCl2 to the cationic surfactants at 25 oC, the inhibition efficiency increases by increasing the concentration of inorganic salts. This behaviour indicating that, the synergism phenomenon exists between cationic surfactant and KI or ZnCl2 leading to increasing the inhibition efficiency
2.2. Potentiodynamic polarization measurements
The data indicated that:-
The presence of the synthesized cationic surfactants in both 1M HCl solution and formation water slightly shifted the corrosion potential (Ecorr) to both negative and positive directions. This indicates that the synthesized cationic surfactants acted as a mixed type inhibitor
For all synthesized cationic surfactants,(icorr) decreased whereas (ηp) increased with increasing the inhibitor concentration. This could be related to the adsorption of the inhibitor over the cathodic and anodic active corroded surface. The increase in corrosion inhibition efficiency of the studied surfactant indicated that the synthesized cationic surfactant had efficient inhibitive properties for the metal surface.
2.3. Electrochemical impedance spectroscopy (EIS)
In both 1M HCl solution and formation water, the data showed that the increase of charge transfer resistance (Rct) and decrease of the pseudo capacity, (Cdl), with increasing the inhibitor concentration indicated that, these compounds have the ability to inhibit the corrosion rate of carbon steel according to adsorption mechanism (formation of a surface film). It was found that the order of the inhibition efficiencies of the cationic surfactants decrease in the following arrangement:
IV(4N) > II(4N) > I(4N)
and these results were in good agreement with those obtained from weight loss and potentiodynamic polarization methods
Other data
| Title | Synthesis and evaluation of some new cationic surfactants as corrosion inhibitors for carbon steel pipelines in oil and gas production " | Other Titles | " تحضير وتقييم بعض المواد ذات النشاط السطحى الكاتيونية الجديدة كمثبطات لتآكل أنابيب الصلب الكربونى المستخدم فى إنتاج الزيت والغاز" | Authors | Ahmed Hussien Ahmed Youssif | Issue Date | 2016 |
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