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,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,Characterization and Surface Activity of New Eco-friendly Schiff Bases Vanillin Derived Cationic Surfactants

Three eco-friendly cationic surface active agents were synthesized from the chemical modification of vanillin. The chemical structures of these surfactants were confirmed using elemental analysis, IR and NMR spectra. The surface activity measurements showed their high tendency towards adsorption and micellization and their good surface tension reduction, low interfacial tension. The emulsion stability measurements showed acceptable efficiency as emulsifying agents for short term emulsions. The biodegradability tests revealed that these compounds are eco-friendly and had completely degraded in 30 days.     

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, 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, Characterization, Biodegradation and Evaluation of the Surface Active Properties of Nonionic Surfactants Derived from Jatropha Oil

Four nonionic surface active agents were synthesized using the fatty acids obtained from the hydrolysis of Jatropha oil. The fatty acids obtained contained different fatty acids including: palmitic, stearic, oleic, linoleic and linolenic acids in different proportions. The chemical structures of the obtained surfactants were characterized using elemental analysis and FTIR spectroscopy. The surface activities of the different surfactants were determined using surface and interfacial tension measurements. The surfactants showed good surface and interfacial activities, which are dependent on their chemical structures. Thermodynamic parameters of adsorption and micellization confirmed these results. The biodegradation tests in river water showed that the surfactants are readily biodegradable, and reached the European standards after 24 days. Surfactants containing longer nonionic chains formed stable emulsions with paraffin oil, while shorter chains exhibit a lower emulsion stability performance.     

Surface Parameters and Biological Activity of <Emphasis Type="Italic">N</Emphasis>-(3-(Dimethyl Benzyl Ammonio) Propyl) Alkanamide Chloride Cationic Surfactants

Three cationic surfactants containing amide groups were prepared by quaternization of dimethylaminopropylamine with benzyl chloride. FTIR and ¹H-NMR spectroscopy were used to confirm the chemical structure of the prepared cationic surfactants. The surface parameters were estimated using surface tension measurements at three different temperatures. The prepared cationic surfactant showed a lower CMC than conventional cationic surfactants. Thermodynamic parameters of adsorption and micellization depend mainly of alkyl chain length and temperature. The adsorption process is more favorable than micellization. The biological activity of the three surfactants was estimated using inhibition zone showing that amidoamine cationic surfactants have good activity and the surfactants C12Bn is the most effective one.     

Micellization and Interfacial Interaction Behaviors of Gemini Cationic Surfactants–CTAB Mixed Surfactant Systems

The interfacial and micellization behaviors of binary mixtures of two gemini cationic surfactants and conventional the cetyl trimethyl ammonium bromide surfactant were studied at various molar ratios. From the equilibrium surface tension measurements, the critical micelle concentrations (CMC) data were obtained as functions of the composition. Values of the CMC were analyzed according to the regular solution model developed by Rubingh for mixed micelles. Two interaction parameters were obtained for each system, the interaction at the interface, and in the micellar phase. The results showed that micellization and adsorption properties of the studied mixed systems depend on the spacer chain lengths of the gemini surfactants and their ratio in the mixed systems.     

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 and Antimicrobial Activities of Cationic Gemini Surfactants with Semi-Rigid Spacers

Four cationic gemini surfactants featuring semi-rigid spacers were synthesized via a two-step process. The surface-active properties of these surfactants were investigated through surface tension and electrical conductivity measurement. The thermodynamic parameters of micellization were evaluated from electrical conductivity measurements at temperatures ranging from 293 to 313 K. The aggregation behavior of these synthesized gemini surfactants in water were investigated using dynamic light scattering and transmission electron microscopy. Further, the antimicrobial activities of these synthesized gemini surfactants against both Gram-positive and Gram-negative bacteria were also investigated.     

Surface Properties,Thermodynamic Aspects and Antimicrobial Activity of Some Novel Iminium Surfactants

Novel iminium compounds namely p-benzylidene benzyldodecyl iminium chloride (I), p-benzylidene benzylhexadecyl iminium chloride (II), p-benzylidene benzyloctadecyl iminium chloride (III) were prepared and characterized using FTIR, ¹H-NMR and mass spectroscopy. The surface properties such as surface and interfacial tension, and biological activity of these surfactants were investigated. The surface parameters including critical micelle concentration, maximum surface excess, and minimum surface area. Efficiency and effectiveness were calculated, as well as free energies of micellization and adsorption. The prepared cationic surfactants exhibit a better biological activity than the used reference cetyl trimethyl ammonium bromide.     

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, Surface and Thermodynamic Properties of Substituted Polytriethanolamine Nonionic Surfactants

Three series of nonionic surfactants derived from polytriethanolamine containing 8, 10, and 12 units of triethanolamine were synthesized. Structural assignment of the different compounds was made on the basis of FTIR and ¹H‐NMR spectroscopic data. The surface parameters of these surfactants included critical micelle concentration (CMC), surface tension at the CMC (γ_CMC), surfactant concentration required to reduce the surface tension of the solvent by 20 mN m^?1 (pC₂₀), maximum surface excess (Γ_max), and the interfacial area occupied by the surfactant molecules (A_min) using surface tension measurements. The micellization and adsorption free energies were calculated at 25 °C.     

Influence of Nonionic Rosin Surfactants on Surface Activity of Silica Particles and Stability of Oil in Water Emulsions

Rosin as a natural product has become a source for production of less toxic bio-surfactants to produce emulsions which are widely used in various agriculture and food products, cosmetic, and pharmaceutical industries. In this respect, a nonionic surfactant was prepared from reaction of rosin acids and rosin maleic anhydride adduct with poly(ethylene glycol) monomethyl ether 750 (MPEG 750) to produce a rosin ester (RMPEG 750). The surface activity parameters of the prepared surfactants, such as surface excess concentration (Γ _max), the area per molecule at interface (A _min), and the effectiveness of surface tension reduction, were measured to determine the micellization and adsorption characteristics of the prepared surfactants at the water/air interface. The adsorption of the prepared surfactants on the surface of either hydrophilic or hydrophobic silica particles was determined using a spectrophotometric method. Interfacial tension between water and toluene were measured to select the best condition to obtain toluene/water emulsion in the presence of modified solid silica particles. The effects of silica particle hydrophilicity and the surfactant concentrations on the surface, interfacial activity, and on the emulsion drop size were also investigated.     

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.     

The Tail Effect of Some Prepared Cationic Surfactants on Silver Nanoparticle Preparation and Their Surface,Thermodynamic Parameters,and Antimicrobial Activity

The surface parameters of some cationic surfactants having different hydrophobic alkyl chains were assessed in aqueous solution using different techniques; surface tension, ultraviolet-Visible (UV–Vis) spectroscopy, and conductivity measurements. The obtained critical micelle concentration (CMC) for N-(2-((3,4-dimethoxybenzylidene)amino)ethyl)-N,N-dimethyloctan-1-aminium bromide (DBAO), N-(2-((3,4-dimethoxybenzylidene)amino)ethyl)-N,N-dimethyldodectan-1-aminium bromide (DBAD), and N-(2-((3,4-dimethoxybenzylidene)amino)ethyl)-N,N-dimethylhexadectan-1-aminium bromide (DBAH) in aqueous solution using three techniques are nearly the same. Increasing the hydrophobic chain length enhances micelle formation. Raising the solution temperature from 25 to 65 °C also shows the same trend. The thermodynamic calculations outlined the adsorption propensity of the surfactants at the surface compared to their affinity to form micelles. Both micellization and adsorption processes are enhanced with both the hydrocarbon elongation and with raising the solution temperature. The effect of the surfactant tail on the preparation process of the silver nanoparticles (AgNP) was assessed and confirmed using transmission electron microscope (TEM), dynamic light scattering (DLS), and UV–Vis spectra. Increasing the surfactant tail leads to a smaller particle size with a narrow distribution. The stability of the prepared AgNP is enhanced with hydrophobic surfactant tail elongation as proved with increasing the zeta-potential of the prepared AgNP colloid. The foaming power, interfacial tension, and emulsification stability of the DBAO, DBAD, and DBAH surfactants were determined. The DBAO, DBAD, and DBAH surfactants showed good antimicrobial activities against both bacteria (Gram positive and negative) and fungi, which have been enhanced because of incorporation of AgNP.     

Surface Activity of Monomeric and Polymeric (3-alkyloxy aniline) Surfactants

ABSTRACT

The adsorption and micellization processes of 3-alkyloxy aniline namely [3-decyloxy aniline (C10M), 3-dodecyloxy aniline (C12M) and 3-cetyloxy aniline (C16M)] and their polymers [C10P, C12P and C16P] have been investigated using surface tension (γ) measurements at different temperatures. The synthesized monomers and polymers have been characterized by IR and elemental analysis. The surface and thermodynamic parameters of these monomeric and polymeric surfactants are investigated. The results show that the critical micelle concentration (CMC) of the polymeric surfactants is lower than that of monomers. The CMC values decreases as the hydrophobic chain lengthens for both monomeric and polymeric surfactants. The surface parameters show the ability of monomeric and polymeric surfactants to adsorb at the air/water interface and decrease the surface tension. The thermodynamic parameters reveal that the micellization process is spontaneous for all investigated surfactants. The specific conductance measurements show that the specific conductance increases with increasing chain length of the substituted alkyl groups, the synthesized polymeric surfactants have higher values of specific conductance than the corresponding monomers and the specific conductance increases with rising solution temperature.     

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.     

Synthesis and Micellization Properties of New Anionic Reactive Surfactants Based on Hydrogenated Cardanol

We report the synthesis, characterization and micellization properties of two anionic reactive surfactants based on 3-pentadecyl phenol obtainable from a renewable resource, cardanol. The synthesis is achieved through simple chemical transformations, first converting the phenol to the acrylate that is sulfonated in a second step. The products were characterized by elemental analysis and spectroscopic techniques. The surfactant properties of the sulfonated acrylates were measured and compared with the standard non-reactive anionic surfactant sodium dodecyl sulfonate. The micellization behavior of aqueous solutions was studied using conductivity, surface tension measurements, and the fluorescence probe technique based on diphenyl hexatriene. Characterization by surface tension measurements facilitated the determination of basic surfactant properties like the critical micelle concentration (CMC), the surface tension at the CMC, surface excess and area per surfactant molecule. The Gibbs free energy of micellization showed a negative value suggesting spontaneous micellization in aqueous solution. The micellization of the surfmer with an ethylene spacer between the phenyl ring and the acrylate group seems to be enhanced as indicated by the lower surface excess and lower free energy. Its CMC was also lower.