Adsorption of some anionic surfactants on barite and at solution/Air interfaces

The adsorption behavior of synthesized anionic surfactants with the chemical structure RO-Ph-N=N-Ph-SO₃Na, where R is an octyl, dodecyl, or cetyl group, was analyzed by using a modified version of the Frumkin adsorption isotherm. The values of thermodynamic parameters (including free energy of micellization, ΔG _mic, and of adsorption, ΔG _ads) at the solution/air interface and the solid/liquid interface were calculated, and the relation between the adsorption of the surfactants at these interfaces was investigated. Studies of the surface properties of these synthetic surfactants showed that the length of the hydrocarbon chain of these surfactants plays a major role in determining their surface and thermodynamic properties and that there is a good relationship between the effectiveness of adsorption of the surfactant and its efficiency as a collector.     

Synthesis,Characterization, Surface and Biological Activity of Diquaternary Cationic Surfactants Containing Ester Linkage

Two series of diquaternary cationic surfactants designated as E9Nm and E11Nm having two different alkyl chains in their chemical structure were synthesized. The chemical structures of these surfactants were confirmed using elemental analysis, FTIR and ¹H‐NMR spectra. The surface activities of the different surfactants were determined using surface and interfacial tension at 25 °C. The surface parameters including: critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area were determined. The surface activities of the cationic surfactants were correlated with their chemical structure. The surface activities of the surfactants increased with increasing the hydrophobic chain length. The adsorption and micellization tendencies of the surfactants in solution were determined using the free energies of adsorption and micellization. The synthesized surfactants were evaluated as biocides against bacteria and fungi. Biocidal activity data showed that a gradual increase in the hydrophobic chain length of the surfactant molecules gradually increases the efficiency of these surfactants as biocides.     

Synthesis and surface activity of poly(maleic diester) surfactants

A series of maleic diester monomers have been prepared by esterification of maleic anhydride with a series of n-alkanols and poly(ethylene glycol) with different molecular weights. These monomers were polymerized in acetic anhydride solution in the presence of cumene hydroperoxide as initiator. The synthesized polymers have been characterized by IR and ¹H NMR spectroscopy, and their surface and thermodynamic properties as non-ionic surfactants is investigated. The surface tension as a function of concentration of the surfactant in aqueous solutions was measured at 298, 308, 318 and 328 K. The surface parameters are calculated. The data reveal that the CMC value of the polymeric surfactant is lower than that of the monomeric surfactant. It is also found that the CMC value decreases with increasing temperature and the number of ethylene oxide units in the surfactant molecule. The thermodynamic parameters of micellization and adsorption are also determined. The structural effectiveness of surface tension is discussed in terms of these parameters. © 1999 Society of Chemical Industry     

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.     

Synthesis,Biological Study and Complexation Behavior of Some Anionic Schiff Base Amphiphiles

A novel series of anionic Schiff base amphiphiles were synthesized. The chemical structures of these compounds were elucidated using different spectroscopic tools. The surface and thermodynamic properties of the prepared Schiff bases were studied using classical measurements including surface and interfacial tensions. The surface parameters of these compounds, e.g., surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess, minimum surface area, and interfacial activity showed their good surface activity. Their thermodynamic parameters of adsorption and micellization including free energy change of micellization and adsorption showed their tendency toward adsorption at the interfaces and also micelle formation at lower concentrations. The complexation behavior of the synthesized Schiff bases were study through the interaction of the Schiff base (IIIa; SBSD) with nickel chloride hexahydrate. All synthesized compounds in addition to NiCl₂·6H₂O and Ni Schiff Base complex have been evaluated for their antibacterial activity against Gram-positive and Gram-negative bacteria. The results of the biocidal activities showed high potent action of (Ni-III_a; Ni-SBSD) complex more than Schiff base IIIa; SBSD.     

Synthesis, Surface, Thermodynamic Properties of Some Biodegradable Vanillin-Modified Polyoxyethylene Surfactants

Four water-soluble non-ionic ethoxylated surfactants based on vanillin were synthesized (VE₁₅, VE₂₀, VE₄₀, and VE₆₀). The chemical structures of these surfactants were confirmed using FT-IR and ¹H-NMR spectra. The molecular weights of the compounds were determined using viscosity measurements and gel permeation chromatography. Surface tension as a function of the concentration of the surfactant in aqueous solution was measured at 25, 40 and 55?°C. From these measurements, the critical micelle concentration (CMC), effectiveness (??_cmc), efficiency (pC₂₀), maximum surface (??_max) excess and minimum surface area (A _min), were calculated. The surface activity measurements showed their high tendency towards adsorption and micellization and their good surface tension reduction, and low interfacial tension. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The thermodynamic parameters of micellization (??G _mic, ??H _mic, ??S _mic) and adsorption (??G _ads, ??G _ads, ?S _ads) showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The biodegradability of the prepared surfactants was tested in river water using die-away method and showed their readily biodegradation in the open environment.     

Environmentally Friendly Nonionic Surfactants Derived from Tannic Acid: Synthesis, Characterization and Surface Activity

In order to discover new and safe surfactants with regard to the environment, new environmentally friendly nonionic surface active agents were synthesized by the reaction of tannic acid (as a natural product presents in several plants) and polyethylene glycol fatty acids containing different numbers of ethylene glycol units. The fatty acids were dodecanoic, hexadecanoic, octadecanoic and oleic acids. The chemical structures of the synthesized surfactants were confirmed using elemental analysis, infrared and ¹H-NMR spectroscopy. The molecular weights of the synthesized surfactants were determined using viscosity measurements and gel permeation chromatography. The surface properties of these surfactants were determined using surface tension measurements. The chemical structure?Csurface activity relationship of these surfactants showed a strong dependence of the surface activity on their chemical structures including the hydrophobic chains and the number of ethylene glycol units incorporated in the molecules. The free energy of micellization of the surfactants in their solutions showed their tendency towards micellization in the bulk of their solutions, while the free energy of adsorption showed their high tendency towards adsorption at the air?Cwater interface.     

Synthesis,Surface Properties and Effect of an Amino Acid Head Group of 11-(2-Methoxy-4-vinylphenoxy)undecanoicacid-Based Anionic Surfactants

Our present research describes the surface properties of three biobased anionic surfactant synthesized from vinylguaiacol and 11-bromo undecanoic acid. To further improve its hydrophobicity and bioavailability, amino acid head group incorporation was carried out. All these synthesized compounds were thoroughly characterized using NMR and mass spectroscopy. The performance properties such as foaming, wetting, emulsification value and calcium tolerance were evaluated. The studied surfactants possess excellent emulsion stability and moderate calcium tolerance as compared to commercially available surfactant sodium lauryl sulfate (SLS). The micelle formation and the thermodynamics involved at the air–water interface were estimated from surface tension measurements. These surfactants showed a higher tendency towards adsorption at the air–water interface than micellization. Dynamic light scattering and steady state fluorescence anisotropy study were carried out to shed light on the bulk micellization properties of the synthesized surfactant. Along with spherical micelles of <5 nm size, larger aggregates (35–84 nm) were observed with higher anisotropy values. FESEM images further confirmed the larger spherical micelles formed by these surfactants. The surfactants formed chiral aggregates above the critical micelle concentration as indicated by circular dichroism spectra. These surfactants may be suitable candidates for additives to detergents to improve their calcium tolerance especially in the case of hard water. Furthermore, a low foaming ability along with high emulsion stability may find these surfactants to be better replacement of the conventional surfactant used as emulsifiers in many industrial applications.     

Development of an electrodeposition nickel polymer composite by a zwitterionic surfactant

A nickel-fluoropolymer composite was produced by electrodeposition. This composite offers many attractive properties that make it ideal for a wide range of industrial applications; it offers very low friction and wear properties on sliding contact surfaces. Several studies were carried out with aqueous zwitterionic surfactant solutions. Critical micelle concentrations, area occupied per molecule, surface excess concentration, free energy of micellization, adsorption, and efficiency were investigated at the solution-air interface. The relationship between the adsorption isotherm at the solution-air interface and at the solid-solution interface was studied. Moreover, the mechanism of incorporation of polytetrafluoroethylene was suggested, and the relationship between thermodynamic parameters of the surfactant and the development of a composite coating was investigated. The results are discussed according to the critical micelle concentrations of the zwitterionic surfactants.     

The Effect of Non Ionic Surfactants Containing Triazole, Thiadiazole and Oxadiazole as Inhibitors of the Corrosion of Carbon Steel in 1M Hydrochloric Acid

In the present investigation novel nonionic surfactants were synthesized, characterized and tested as inhibitors of the corrosion of carbon steel in 1M HCl solution. The inhibition action of these surfactants was studied by weight loss, galvanostatic polarization and electrochemical impedance spectroscopy. The adsorption of the inhibitors was well described by the Langmuir adsorption isotherm and the adsorption isotherm parameters were determined at different temperatures. The inhibition efficiency was found to rise when increasing the concentration of these compounds and decreasing the temperature. The effect of temperature on the inhibition efficiency of the corrosion process was studied and the values of some activated thermodynamic parameters were calculated to elaborate the mechanism of inhibition. The synthesized nonionic surfactants exhibit good surface and antimicrobial properties.     

Characterization,surface properties and biological activity of some synthesized anionic surfactants

In this study, esterification reaction between four different fatty alcohols (octyl, dodecyl, hexdecyl and octadecyl alcohol) and phosphoric acid was performed. The produced compound was reacted with polyethylene glycol-400. Then, the reaction product was quenched using sodium hydroxide to form the desired anionic gemini surfactants. The chemical structures of the synthesized surfactants were recognized by FT-IR and ¹H NMR spectroscopy. The synthesized surfactants showed higher surface activity. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The foaming power measurements showed the synthesized surfactants have low ability to foam formation. The thermodynamic parameters showed their tendency toward adsorption at the interfaces and also micellization in the bulk of their solutions. The studied surfactants were evaluated as antimicrobial agents against pathogenic bacteria using inhibition zone diameters. The synthesized surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The promising inhibition efficiency of these compounds against the pathogenic bacteria facilitates them to be applicable in the petroleum field as new categories of biocides.     

Novel Gemini Cationic Surfactants: Thermodynamic,Antimicrobial Susceptibility,and Corrosion Inhibition Behavior against Acidithiobacillus ferrooxidans

The Egyptian oil and gas industry is suffering from severe metal corrosion problems, particularly microbial-induced corrosion. There is limited knowledge on the corrosion inhibition of carbon steels in the presence of an acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans. Therefore, in this study, novel Gemini cationic surfactants, in three forms depending on variation in alkyl chains of 8, 12, and 16 carbon atoms named FHPAO, FHPAD, and FHPAH, respectively, were synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopy. The surface parameters and the thermodynamic of the synthesized surfactants were evaluated at three different temperatures, 20, 40, and 60 °C. The synthesized Gemini cationic surfactants were tested as broad-spectrum antimicrobial, antibacterial and anticandida agents. They evaluated as biocides and corrosion inhibitors against Acidithiobacillus ferrooxidans. FHPAD showed higher adsorption ability at the solution interface and higher affinity to construct micelles than FHPAO and FHPAH. Both adsorption and micellization processes were hydrophobic and temperature dependent. FHPAO, FHPAD and FHPAH exhibited wide-spectrum antimicrobial activities, and the highest activity and the lowest minimum bactericidal/fungicidal inhibitory concentrations were attributed to FHPAD. Furthermore, synthesized FHPAD demonstrated the highest metal corrosion inhibition efficiency of 95.5% at 5 mM in comparison to 87.5% and 81.7% for FHPAO and FHPAH, respectively. In conclusion, this study provides novel synthesized cationic surfactants with many applications in the oil and gas industry, such as broad-spectrum antimicrobial, biocides, and corrosion inhibitors for acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans.     

Synthesis and Properties of Quaternary Ammonium Surfactants Based on Alkylamine,Propylene Oxide,and 2‐Chloroethanol

New quaternary ammonium salts are synthesized by octylamine, nonylamine, dodecylamine, and hexadecylamine reacting with propylene oxide at a mole ratio of 1:2, followed by reaction with 2‐chloroethanol. By tensiometric measurements of aqueous solutions, their surface activity has been determined. Using the results of these measurements and electroconductometric studies, important parameters such as critical micelle concentration (CMC), efficiency of surfactant adsorption, surface pressure at the CMC, changes of Gibbs free energies for micelle formation, and adsorption were estimated. By application of the Gibbs adsorption isotherm, indices such as maximum surface excess concentration and minimum surface area/molecule at the air–water interface were also calculated. Petroleum‐collecting properties of these surfactants were investigated. Among these quaternary ammonium surfactants, the surfactant based on dodecylamine, propylene oxide, and 2‐chloroethanol exhibits the highest petroleum‐collecting capacity.     

Surface Activity,Thermodynamics of Micellization and Adsorption Properties of Quaternary Salts Based on Ethanolamines and Decyl Bromide

The surface-active properties of ionic-liquid type salts synthesized by the interaction of ethanolamines and decyl bromide have been studied. Surface tension as a function of concentration of the surfactant in aqueous solution was measured at 10, 20, 30 and 40 °C using a drop volume stalagmometer. From these measurements, the maximum surface excess concentration and the minimum area per molecule at the aqueous solution/air interface, the critical micelle concentration (CMC), the surface pressure at the CMC, and the standard thermodynamic parameters of adsorption and micellization were calculated. The structural effects on adsorption, micellization, and the effectiveness of surface tension reduction are discussed in terms of these parameters.     

CORROSION INHIBITION OF STEEL PIPELINES IN OIL WELL FORMATION WATER BY A NEW FAMILY OF NONIONIC SURFACTANTS

A new family of nonionic surfactants was synthesized and evaluated as corrosion inhibitors for steel pipelines in oil well formation water. Polarization data show that the selected surfactants act as mixed-type inhibitors. EIS results show that the change in impedance parameters (R_t and C_dl) with the concentration of the surfactants studied is indicative of the adsorption of surfactant molecules on carbon steel surface, leading to formation of a good protective film. The properties of this film were studied by various surface analysis tools. Finally, the relation between the surface properties of the inhibitor molecules and corrosion inhibition efficiency is discussed.     

Gemini Cationic Surfactants: Synthesis and Influence of Chemical Structure on the Surface Activity

Three cationic gemini surfactants were synthesized and characterized using different methods. Their surface activities were measured using surface and interfacial tension measurements. The effect of the spacer chain length on the surface activity, emulsification power and interfacial tension was studied. The thermodynamic parameters showed the tendency towards micellization and adsorption. The results showed that longer spacers increased the micellization tendencies of the surfactants, while shorter spacers increased the adsorption tendency at the air–water interface.     

The effect of type of self-assembled system and pH on the efficiency of corrosion inhibition of carbon-steel surfaces

In this work, three surfactants were used in the preparation of self-assembled systems to inhibit acidic corrosion on API5LX Gr X52 carbon-steel surfaces: CTAB (a cationic surfactant), SDS (an anionic surfactant), and C₁₂E₉ (a non-ionic surfactant). These surfactants were used in the form of aqueous solutions and in microemulsions. Pseudoternary diagrams were constructed using aqueous phases consisting of 0.5 M NaCl at pH = 2, 4 and 7, butan-1-ol as co-surfactant and kerosene as oil phase. The values of c.m.c., maximum surface excess, minimum surfactant cross-sectional area and free energy of micellization were determined using surface tensiometry. The distinct effects of pH and type of self-assembled system on the efficiency of corrosion inhibition have been elucidated by electrochemical techniques (polarization and Tafel curves). It has been demonstrated that these parameters can significantly affect the results, which depend largely on the mechanism of aggregate adsorption on the metal surface and droplet stability. By establishing the optimal conditions, excellent corrosion efficiencies were found for these systems, even at low surfactant concentrations.     

Synthesis,Characterization and Surface Activities of Cationic Polysaccharide (Aloe) Schiff Base Surfactants

Synthesis of cationic polysaccharide (Aloe) Schiff base surfactants was described and their chemical structures were confirmed by using FTIR spectroscopic, H‐NMR and UV analysis. The surface activities of these surfactants were measured, including surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area at 25 °C, interfacial tension and emulsification power at 25 °C. Adsorption and micellization free energies of these amphiphiles in their solutions showed a good tendency towards adsorption at the interfaces.     

Synthesis of Animal Fats Ethylolamides,Ethylolamide Phosphates and Their Petroleum-Collecting and Dispersing Properties

Ethylolamides of animal (beef and mutton) fats have been synthesized and modified with H₃PO₄. The identity of these products was confirmed by IR and NMR spectroscopy. The physical properties of the synthesized surfactants including interfacial tension and critical micelle concentration (CMC) were studied. From these measurements, the maximum surface excess concentration and the minimum area per molecule at the kerosene solution/water interface, the surface pressure at the CMC, and the standard thermodynamic parameters of adsorption and micellization were calculated. Ethylolamides and ethylolamide phosphates were obtained and tested as petroleum-collecting and petroleum-dispersing reagents. Some correlations between these parameters of the ethylol units and their ability to collect thin petroleum films from the water surface were revealed.     

Surface Properties and Thermodynamic Parameters of Some Sugar-Based Ethoxylated Amine Surfactants: 1—Synthesis,Characterization, and Demulsification Efficiency

Several ethoxylated sugar-based amine surfactants have been synthesized and characterized by IR and ¹HNMR spectroscopy. The surface activity of the prepared compounds has been thoroughly studied and some of their surface properties (such as CMC, Γ_max, and A _min) have been calculated. The surface properties of the prepared compounds were correlated to their chemical structure. It was found that CMC decreases when increasing the molecular weight of polyethylene glycols, whereas A _min increases. Furthermore, the thermodynamic parameters of adsorption and micellization were also calculated. They include ΔG, ΔH, and ΔS of micellization and adsorption. The data show that the synthesized surfactants favor adsorption, so that they can be used as demulsifiers for crude oil emulsions. In this respect, the demulsification test was carried out and the results of demulsification efficiency were correlated to the chemical composition of the investigated compounds. Some factors that affect the demulsification efficiency were also considered.