New Schiff Base Cationic Surfactants: Surface and Thermodynamic Properties and Applicability in Bacterial Growth and Metal Corrosion Prevention

A new series of cationic Schiff bases was synthesized and their chemical structures were confirmed using elemental analysis, infrared spectra and nuclear magnetic resonance. The surface properties of the surfactant solutions including surface tension, effectiveness, efficiency, critical micelle concentration, maximum surface excess and minimum surface area were calculated using surface tension-log concentration profiles. The surface parameters were strongly dependent on the hydrophobic chain length. The thermodynamic properties of the surfactants in their solutions showed the spontaneous behavior of both adsorption and micellization processes. The thermodynamic data revealed that the adsorption of the surfactant molecules at the air/water interface was more favorable than the micellization in the bulk of their solutions. The synthesized surfactants were evaluated with regard to their preventing the corrosion reaction of carbon steel in acidic media and also their acting as antibacterial biocides to inhibit bacterial growth. The data of corrosion and antibacterial evaluations showed the high efficiency and applicability of these compounds in these uses.     

Synthesis of Quaternary,Long-Chain N-Alkyl Amides and Their Corrosion Inhibition in Acidic Media

New cationic surfactants were synthesized by the quaternization of a number of straight-chain amide derivatives with triethylamine or pyridine. The corrosion inhibition tests of the surface-active compounds were performed at room temperature for 24 h on carbon steel coupons in acidic media using the gravimetric method. The acidic media used were 1.5 M HCl and 1.5 M H₂SO₄. Almost all of the synthesized cationic surfactants showed efficient inhibition of corrosion in the test. To establish the inhibition efficiencies of the inhibitors, surface characterization studies (contact angle measurements, SEM analysis and optical profilometer images) of the metal coupons used were performed.     

Novel Imidazolium-Based Gemini Surfactants: Synthesis, Surface Properties, Corrosion Inhibition and Biocidal Activity Against Sulfate-Reducing Bacteria

Three novel imidazolium-based gemini surfactants had been synthesized and characterized using different spectroscopic techniques. The surface properties of the synthesized surfactants were determined using surface tension measurements at 20 °C. The surface parameters including critical micelle concentration (CMC), π _CMC, Pc₂₀, Γ_max and A _min were determined. The synthesized compounds were evaluated as corrosion inhibitors for carbon steel in 0.5 M HCl solution using the weight loss and polarization techniques. The biological activity of these surfactants was evaluated against sulfate reducing bacteria using most probable number method. The results indicate that the synthesized compounds have good surface properties and are proper corrosion inhibitors for low carbon steel, with a high inhibition efficiency observed around their CMC. These compounds exhibit a significant biocidal activity against sulfate reducing bacteria.     

Some Schiff Base Surfactants as Steel-Corrosion Inhibitors

Two series of Schiff base amphiphiles were prepared by condensation of benzaldehyde or anisaldehyde with three different alkyl chain length fatty amines namely: dodecyl, hexadecyl and octadecyl amine. The chemical structures of the prepared Schiff bases were confirmed by using different techniques, (elemental analysis, FTIR and ¹H-NMR spectra). The data of structural analysis for these compounds were confirmed by the purity of the synthesized amphiphiles. The synthesized Schiff bases were evaluated as corrosion inhibitors for low carbon steel (mild steel) in various acidic media (HCl and H₂SO₄) using a weight loss technique. The corrosion inhibition measurements of these inhibitors showed high protection against corrosion process in the tested acidic media at different doses (50, 100, 150 and 200 ppm) as well as their having a good biocidal effect against sulphate reducing bacteria. The discussion correlated the efficient corrosion inhibition of these inhibitors to their chemical structures.     

Enhancing of Corrosion Inhibition and the Biocidal Effect of Phosphonium Surfactant Compounds for Oil Field Equipment

It is well known that tetra hydroxymethyl phosphonium sulfate (THPS) is commonly used in oil fields as a biocide for sulfate-reducing bacteria (SRB), but it has low corrosion inhibition. In this study, four phosphonium surfactant compounds were synthesized via a coupling reaction between THPS and different fatty acids namely: decanoic, dodecanoic, palmitic and stearic acids to produce the corresponding surfactants. The chemical structure of the synthesized surfactants was confirmed using FTIR and ¹H-NMR spectroscopy. The surface activity of the prepared compounds was determined by surface tension measurements. The critical micelle concentration (CMC) of each surfactant compound was determined. The corrosion inhibition of the synthesized compounds on carbon steel in 0.5 M HCl was studied by weight loss measurements, potentiodynamic and electrochemical impedance spectroscopy. The effect of the inhibitor concentration and hydrophobic chain length on the their efficiency was also studied. It was found that the CMC of each compound depends on its chemical structure. It was also found that the corrosion inhibition efficiency depends on both of concentration and molecular structure of the inhibitors. Polarization curves revealed that the inhibitors used represent mixed-type inhibitors, which hinder the cathodic and anodic parts of the corrosion reaction in acidic media. Adsorption of used inhibitors leads to a reduction in the double layer capacitance and an increase in the charge transfer resistance. Also the biocidal effect of these compounds was enhanced.     

Synthesis and Evaluation of Nonionic Surfactants Derived from Tannic Acid as Corrosion Inhibitors for Carbon Steel in Acidic Medium

Nonionic Schiff base surfactants were synthesized by chemical modification of tannic acid. The surface activities of the synthesized surfactants were determined using surface tension, interfacial tension, and emulsification properties. Thermodynamic parameters of adsorption and micellization of these surfactants showed their tendency towards the two processes with greater predominance of adsorption over micellization. Electrochemical polarization and impedance measurements showed that the surfactants exhibited good tendency towards inhibiting the dissolution of carbon steel in acidic medium. The inhibition efficiencies depend on the chemical structure and concentration of the compounds.     

Corrosion Inhibition Efficiency,Electrochemical and Quantum Chemical Studies of Some New Nonionic Surfactants for Carbon Steel in Acidic Media

In this work, three types of nonionic surfactant as corrosion inhibitors were synthesized. The chemical structure of the prepared inhibitors was confirmed using FT‐IR and ¹H‐NMR spectroscopy. The surface tension and thermodynamic properties of these inhibitors were investigated. The corrosion inhibition efficiency of these surfactants was investigated on a carbon steel surface in 1 M HCl solution by weight loss and electrochemical measurements. Untreated and treated steel surfaces were characterized by scanning electron microscopy. Results show that the inhibition efficiency of the prepared inhibitors increases with increasing the ethylene oxide units. Also, the potentiodynamic polarization curves indicated that the investigated inhibitors behave as a mixed type inhibitor. Adsorption of these surfactants on the carbon steel surface was found to obey Langmuir's adsorption isotherm. The computed quantum chemical properties viz., electron affinity (EA), highest occupied molecular orbital (E_HOMO), the lowest unoccupied molecular orbital (E_LUMO), energy gap ΔE = E_HOMO ? E_LUMO, dipole moment (μ), polarizability and total energy (E_T) show good correlation with experimental inhibition efficiency.     

Some Imidazoline Derivatives as Corrosion Inhibitors

In this study, cationic surfactants having different alkyl chain lengths were prepared by amidation of lauric, myristic, palmitic, stearic, oleic acids with diethylene triamine. The products were quaternized using chloroacetic acid. The chemical structure of the prepared compounds was elucidated using different spectroscopic techniques. The critical micelle concentration (CMC) and the free energy of the micellization and adsorption of these compounds were determined by surface tension and conductivity measurements. The products were evaluated as surface-active agents as well as corrosion inhibitors for steel alloy in 1 M hydrochloric and sulfuric acid, the results indicate that these materials have a high efficiency as corrosion inhibitors and as surface active agents. These results were correlated with the chemical structure of the prepared compounds.     

Corrosion Inhibition by Some Cationic Surfactants in Oil Fields

Two cationic surfactants, namely, tetradecyl dimethyl benzyl ammonium chloride (TDBAC) and tributyl tetradecyl phosphonium chloride (TTPC) were supplied from the local market and characterized. The adsorption tendency of the two surfactants was estimated from the values of the depression of surface tension of the water at the critical micelle concentration. The studied surfactants were evaluated as antimicrobial agents against sulfate-reducing bacteria. These cationic surfactants showed good antimicrobial activities against the tested microorganisms. It was also found that these compounds are good corrosion inhibitors for carbon steel in 0.5?M HCl at doses of 25?C600?ppm.     

Synthesis and Characterization of Multifunctional Surfactants in Oil-Field Protection Applications

A series of cationic surfactants was prepared using economical raw materials. The chemical structures of the prepared compounds were confirmed using elemental analysis, FTIR and ¹H-NMR spectra, and melting point determination. The synthesized surfactants were evaluated as oil-field protective additives. In this regard, several surface properties of the synthesized surfactants were studied including surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area. The results obtained from the surface activity measurements were correlated to their chemical structures. The emulsification power measurements for solutions of these surfactants showed their low emulsifying tendency towards paraffin and crude oil. The synthesized surfactants also exhibited high biocidal activity towards gram-positive and gram-negative bacteria and fungi. This activity was increased by increasing the hydrophobic chain length. The corrosion inhibition measurement of these surfactants for mild steel alloys in acidic media using a weight loss technique showed good protection of mild steel alloys against acidic environments. These properties qualify the synthesized compounds as economical oil-field protective additives.

Screening for Potential Antimicrobial Activities of Some Cationic Uracil Biocides Against Wide-Spreading Bacterial Strains

Eight novel uracil-based cationic surfactants containing Schiff base species were synthesized and characterized using elemental analysis, FTIR, ¹H-NMR and ¹³C-NMR spectroscopy. The surface activities of the synthesized Schiff bases and their cationic derivatives were determined based on interfacial tension measurements and partition coefficient values in water/octanol system. The synthesized Schiff bases and their cationic derivatives were evaluated as novel biocides against different bacteria and fungi strains. The results showed that the biocidal activity of the synthesized Schiff bases was considerably increased by quaternization. The influence of the cationic surfactants as biocides was increased by increasing the hydrophobic chain length and the presence of the methoxy groups. The biocidal activity was also increased by increasing the partition coefficient in water/octanol system. The structure and surface activity/biocidal activity of the different compounds were discussed.     

Synthesis of Bis[<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-(alkylamideethyl)ethyl] Triethylenediamine Bromide Surfactants and Their Oilfield Application Investigation

Bis[N,N′-(alkylamideethyl)ethyl] triethylenediamine surfactants are quaternary ammonium salt Gemini surfactants with amide, which are synthesized from fatty acid (dodecanoic, hexadecanoic, tetradecanoic and octadecanoic) methyl esters, triethylene tetramine and ethyl bromide. The chemical structures of the prepared compounds were characterized by elemental analysis, FTIR and ¹H-NMR spectra, melting point and Krafft point. Several properties of the synthesized surfactants were studied including surface tension, critical micelle concentration, interfacial tension, emulsification power, salt effect, corrosion inhibition efficiency and biological activity. The results show that the surface activity, critical micelle concentration and interfacial activity are correlated to their chemical structures. The emulsification power measurements of these surfactants show their low emulsifying tendency towards Tazhong’s crude oil from Tarim Oilfield. The synthesized surfactants also exhibit high biocidal activity towards Gram-positive and Gram-negative bacteria and fungi. This activity increases with the increase of alkyl chain length. The corrosion measurement of these surfactants in acidic media with a weight loss technique show good protection of mild steel alloys against acidic environments. These properties suggest that the synthesized compounds have potential for application in the oilfield area.     

Novel Amide-Based Cationic Surfactants as Efficient Corrosion Inhibitors for Carbon Steel in HCl and H2SO4 media

A variety of surface active compounds were synthesized by the quaternization of some straight chain amide derivatives with triethylamine or pyridine. Their structure FT-IR and ¹H-NMR spectra were recorded. In addition their physical properties and corrosion prevention efficiencies were investigated. All compounds were tested with steel coupons in acidic media by the gravimetric method. As acidic media 1.5 M HCl and 1.5 M H₂SO₄ were used and the corrosion inhibition tests fulfilled at room temperature for 24 h. Almost all prepared cationic surfactants showed efficient inhibition around their critical micelle concentrations. The effects of HCl concentration on corrosion inhibition of some synthesized compounds were also investigated. The corrosion tests were supported by contact angle measurements.     

Corrosion inhibition and Biocidal effect of some cationic surfactants based on Schiff base

The three cationic surfactants based on Schiff base were laboratory prepared, (E)-decyl-4-[(2-hydroxyethylamino) methyl]-N,N-dimethyl benzenaminium bromide (I), (E)-dodecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (II) and (E)-hexadecyl-4-[(2-hydroxyethylamino)methyl]-N,N-dimethyl benzenaminium bromide (III) were evaluated as corrosion inhibitors for carbon steel in acid medium and antimicrobial agents against sulfate reducing bacteria, SRB. Three techniques were used for the corrosion inhibition evaluation, namely; weight loss, polarization and electrochemical impedance. The serial dilution method was used to evaluate the inhibiting effect of these compounds on the sulfate reducing bacteria growth. The results showed that the prepared compounds have good antimicrobial activities against the SRB as well as they have high efficiency as corrosion inhibitors for carbon steel in 1 M HCl.     

Characterization,surface properties and biological activity of new prepared cationic surfactants

Three cationic surfactants were prepared. A condensation reaction between dimethylaminopropylamine (DMAPA) and benzaldehyde was performed. The produced Schiff base was quaternization with three fatty alkyl bromide with different carbon chain length separately to form the desired cationic surfactants. The chemical structure of synthesized cationic surfactants was confirmed by FTIR, ¹H NMR and mass spectroscopy. It was found that the chemical structure of prepared compounds has an effect on surface properties, where increasing the hydrophobic chain length decrease the values of CMC, Г_max while A_min value was increased. The thermodynamic parameters showed that adsorption and micellization processes are spontaneous. It is clear that the prepared cationic surfactants at first tend to adsorb at surface, then it aggregate to form micelle. The prepared surfactants showed good biological activity against gram positive and negative bacteria and fungi in the following order of II (C12) > I (C10) > III (C16). The serial dilution method was used to evaluate the inhibiting effect of these compounds on the sulfate reducing bacteria growth.     

Evaluation of Some Nonionic Surfactants Derived From Vanillin as Corrosion Inhibitors for Carbon Steel During Drilling Processes

Four eco‐friendly nonionic surfactants based on vanillin were investigated as corrosion inhibitors against carbon steel dissolution during the drilling process in the oil field. The corrosion inhibition efficiencies of the tested compounds were determined using weight loss, electrochemical polarization, and electrochemical impedance techniques. The data obtained show that the nonionic surfactants prevent the corrosion of drilling tools and their inhibition efficiency increased with an increase in their concentration. Tafel curves revealed that the surfactants under study act as mixed inhibitors. The adsorption of the inhibitors on carbon steel surface decreases the double‐layer capacitance. The inhibition efficiencies of the surfactants were influenced by their chemical structure and surface activity.     

Effectiveness of some non ionic surfactants as corrosion inhibitors for carbon steel pipelines in oil fields

The ability of new synthesized non ionic surfactants (I and II) to protect carbon steel in acid chloride solution was investigated using potentiostatic polarization, open circuit potential, weight loss and surface tension measurements. The experimental results showed that these inhibitors revealed a very good corrosion inhibition even at low concentrations. The percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (cmc) is reached. It was found that, the adsorption ability of the surfactant molecules on carbon steel surface increased with the increase of the molecular size of the surfactant. Potentiostatic polarization curves indicate that the inhibitors under investigation act as mixed type. Finally, the mechanism of carbon steel dissolution in acidic medium was discussed both in absence and presence of the inhibitor molecules.     

Retracted: Synthesis,Characterization, and Surface Activities of Polymeric Cationic Thiol Surfactants in Aqueous Medium

A series of cationic polyurethane surfactants [PQ_8-18] were synthesized by the reaction of alkyl bromoacetate (namely: octyl-, decyl-, dodecyl-, tetradecyl-, hexadecyl-, and octadecyl bromoacetate) as quaternizing agents and modified polyurethane contains tertiary amine species. Modified polyurethane was prepared by the reaction of toluene diisocyanate (TDI) and triethanol amine monomercaptoacetate. The chemical structures of the prepared surfactants were confirmed using elemental analysis, Fourier transform infrared spectroscopy (FTIR), and Proton nuclear magnetic resonance (¹H NMR) spectroscopy. The molecular weight measurements of the prepared polymers showed that the segments of each polymer contain average 10 units of the urethane-triethanol amine mercaptoacetate. The surface activities of the prepared surfactants including: surface tension (γ), effectiveness ( π_cmc), concentration at micelle formation (CMC), efficiency (Pc₂₀), maximum concentration at the interface (Γ_max), and the average area occupied by each surfactant molecule at the interface at equilibrium ( A _min) of surfactants solutions were established at 25°C. The surface tension and the critical micelle concentration values of the prepared surfactants were gradually decreased by the gradual increase of their alkyl chain length. The prepared cationic surfactants showed efficient activity as inhibitors for dissolution of carbon steel in an acidic medium and also as a biocide against the growth of bacteria, fungi, and yeast.     

Synthesis,Surface Properties,and Inhibiting Action of Novel Nonionic Surfactants on Carbon Steel Corrosion in 1 M Hydrochloric Acid Solution

In the present study novel nonionic surfactants were synthesized, characterized, and tested as corrosion inhibitors for carbon steel in 1 M HCl solution. The inhibiting performances of these surfactants were studied by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The adsorption of these inhibitors was well described by Langmuir adsorption isotherm, and the kinetic parameters were calculated and discussed. The inhibition efficiency (IE) was found to rise with increasing the concentration of these inhibitors. Polarization measurements revealed that the inhibitors acted as mixed-type inhibitors. The efficiencies obtained from the impedance measurements were in good agreement with those obtained from the weight loss and potentiodynamic polarization techniques which prove the validity of these tools in the measurements of the tested inhibitors. The surface parameters of the synthesized nonionic surfactants were investigated and the results showed that these surfactants have lower values of surface tension and are effective as wetting and emulsifying agents.     

Corrosion inhibition of some novel hydrazone derivatives

A novel series of surfactants was synthesized via direct interaction of the hydrogen-accepting benzyl monophenyl hydrazone and different hydrogen-donating sulfate, sulfonate, sulfosuccinate, or taurate species in their acid form. The double salt surfactants produced had a benzyl monophenyl hydrazonium (PH) moiety as the cation, and lauryl sulfate, dodecylbenzene sulfonate, dioctyl sulfosuccinate, N-cetyloxycarbonyl ethyltaurate (COCET), and N-stearyloxycarbonyl ethyltaurate as the anion. The structural elucidation of the synthesized compounds was carried out using different analytical tools such as elemental analyses, sharp melting points, and Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy. Surface properties of these synthesized hydrazonium derivatives, including surface tension and emulsion stability, were measured and correlated with their chemical structure. The corrosion inhibition efficiency of these hydrazonium derivatives at different concentrations (20, 40, 60, 80, and 100 ppm) was measured in brine containing 5% H₂S as the corrosive medium. The inhibition efficiency results were discussed according to the inhibitor concentrations in the corrosive medium, chemical structures, surface properties, and hydrophile-lipophile balance of these inhibitors. The corrosion inhibition measurements of these compounds showed that PH-COCET exhibits good efficiency at all concentration ranges.