Amino Acid Surfactants Research Articles

Experimental investigation into l-Arg and l-Cys eco-friendly surfactants in enhanced oil recovery by considering IFT reduction and wettability alteration

Surfactant flooding is an important technique used to improve oil recovery from mature oil reservoirs due to minimizing the interfacial tension (IFT) between oil and water and/or altering the rock wettability toward water-wet using various surfactant agents including cationic, anionic, non-ionic, and amphoteric varieties. In this study, two amino-acid based surfactants, named lauroyl arginine (l-Arg) and lauroyl cysteine (l-Cys), were synthesized and used to reduce the IFT of oil–water systems and alter the wettability of carbonate rocks, thus improving oil recovery from oil-wet carbonate reservoirs. The synthesized surfactants were characterized using Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses, and the critical micelle concentration (CMC) of surfactant solutions was determined using conductivity, pH, and turbidity techniques. Experimental results showed that the CMCs of l-Arg and l-Cys solutions were 2000 and 4500 ppm, respectively. It was found that using l-Arg and l-Cys solutions at their CMCs, the IFT and contact angle were reduced from 34.5 to 18.0 and 15.4 mN/m, and from 144° to 78° and 75°, respectively. Thus, the l-Arg and l-Cys solutions enabled approximately 11.9% and 8.9% additional recovery of OOIP (original oil in place). It was identified that both amino-acid surfactants can be used to improve oil recovery due to their desirable effects on the EOR mechanisms at their CMC ranges.

Interfacial Dilational Rheology of Sodium Lauryl Glycine and Mixtures with Conventional Surfactants

AbstractAmino acid‐based surfactants are environmentally friendly surfactants, which have aroused increasing interest. In the application of amino acid‐based surfactants, they are often compounded with other kinds of surfactants to obtain formulations that meet certain requirements. Herein, sodium lauroyl glycinate (C12‐Gly‐Na) was selected as a representative amino acid‐based surfactant to compound with an anionic surfactant (sodium dodecyl sulfate [SDS]), a cationic surfactant (dodecyl trimethyl ammonium Bromide), and a nonionic surfactant (Triton X‐100: p‐octyl polyethylene glycol phenyl ether). Surface tension measurements and interfacial dilational rheological experiments were performed to study the interfacial behaviors of C12‐Gly‐Na and its mixtures. The results show that mixture systems have better interfacial activity than individual C12‐Gly‐Na and there is an obvious synergy between C12‐Gly‐Na and C12TAB under strong electrostatic attraction. Thus, the C12‐Gly‐Na/C12TAB mixture shows lower critical micelle concentration (CMC) and γCMC and higher dilational modulus than the individual surfactants. Besides, the film formed by the C12‐Gly‐Na/C12TAB mixture has higher viscoelasticity than single C12‐Gly‐Na and its mixtures with SDS and TX‐100. With the increase of bulk concentration, the dilational moduli of C12‐Gly‐Na, C12‐Gly‐Na/SDS, and C12‐Gly‐Na/TX‐100 run through two maxima, while, due to stronger electrostatic attraction, only one maximum appears in the C12‐Gly‐Na/C12TAB system. The study of the interfacial properties of amino acid surfactant and its mixtures with other surfactants provides a theoretical foundation for potential applications in cosmetic, food processing, and daily chemical industries.

Ajinomoto to boost amino acid surfactants

Ajinomoto will spend more than $20 million to build a facility in Brazil for amino acid–based surfactants. Set to open in the fall of 2020, the plant will increase the firm’s capacity for the materials by about 20%. Demand for the mild, biodegradable surfactants has been growing at 15% annually, Ajinomoto says.

Study on foaming properties of N-acyl amino acid surfactants: Sodium N-acyl glycinate and sodium N-acyl phenylalaninate

A detailed study on the foaming properties of sodium N-acyl glycinate(N-CnG, n = 12, 14,16,18)and sodium N-acyl phenylalaninate(N-CnP, n = 12, 14,16,18)with different carbon chain lengths were performed. The effects of hydrophilic group, hydrophobic group, surfactant concentration and temperature were evaluated on the foamability, foam morphology and foam stability by foam scanning method. The results showed that the foamability and foam stability of N-C12G were better than that of N-C12P. In addition to N-C14P, with the increase of alkyl carbon chain, the foamability of sodium N-acyl amino acid decreased, but the foaming stability gradually increased. With the increase of concentration, the foamability of the two kinds of surfactants increased first and then decreased. The increase of temperature was beneficial to the foamability of N-CnP, but the foam stability decreased. At higher temperatures, the longer alkyl chain was, the stronger the foamability and foam stability of N-CnP were. With the increasing of alkyl carbon, the maximum liquid carrying capacity and liquid drainage rate of N-CnG decreased. At the same concentration and alkyl carbon number, N-CnP had higher maximum liquid carrying capacity than N-CnG. The number of bubbles initially increased and then decreased, and the morphology of bubbles gradually changed from sphere to polyhedron.

Preparation and surface activity study of amino acid surfactants

Quaternary ammonium cationic surfactants are widely applied in many different fields, such as textile, cosmetic, and petrochemical industries. However, little research has been done on the effects of anion on cationic surfactants. In this study, two new surfactants, cetyltrimethylammonium glycine (CTAG) and octadecyltrimethylammonium glycine (OTAG), were prepared in a simple way using cetyltrimethylammonium chloride (CTAC), octadecyltrimethylammonium chloride (OTAC), and glycine. Then the surface activities were evaluated and compared with the two raw materials. The surface activity of CTAG and OTAG, including surface tension, foaming ability, and emulsification, is better than that of CTAC and OTAC in each case. With the glycine, the corrosion inhibition efficiencies of CTAG and OTAG are 91.12% and 97.89%, respectively, which are more effective than that of CTAC and OTAC. The superior performance of the two surfactants will be very helpful for developing an effective solution in the future.

Micellization of Carboxylic Acid Gemini Surfactant and Its Interaction with Amino Acid Surfactant in Aqueous Solution

AbstractThe carboxylic acid‐type Gemini surfactant (CGS12) was synthesized, and its micellization in aqueous solution at different pH values at 25.0 °C was investigated. The results show that the critical micelle concentration (CMC) of CGS12 at different pH values is only 10−6 order of magnitude, and the pH has little effect on the CMC. Moreover, the interaction of CGS12 with amino acid surfactant of sodium N‐lauroyl sarcosinate (SLS) at 25.0 °C and pH 7.0 was investigated using surface tension, dynamic light scattering (DLS), cryogenic transmission electron microscopy (Cryo‐TEM), and Ross–Miles foam measurements. The CGS12/SLS mixture shows a low CMC, and as a whole the CMC value becomes smaller with increasing molar fraction of CGS12 (XCGS12). Under different XCGS12, the mixtures form soluble aggregates with different hydration radii (Rh). Moreover, the mixture aggregates are mainly in the form of vesicles. The foaming height of CGS12 is worse than that of SLS, but the CGS12/SLS mixture has good foaming stability. This work reveals that the surfactant mixture has good surface activity and good foam stability.

Interfacial activities and aggregation behaviors of N-acyl amino acid surfactants derived from vegetable oils

The development of amino acid surfactants which are considered to be biodegradable and less toxic than traditional surfactants has been a subject of growing interests among chemists for the past 20 years. Within this category, N-acyl amino acid surfactants are popular due to their excellent interfacial properties and antimicrobial activities. In the present work, six new N-acyl amino acid surfactants were synthesized using vegetable oils (castor oil and cottonseed oil) and amino acids (glycine, alanine, and serine). Surface active properties of these surfactants were investigated. With the amide bonds acting as hydrogen bond donors and acceptors, globular and tubular vesicles were observed in the aqueous solutions of some prepared surfactants. The results indicated that hydroxyl groups on the hydrophobic tails for castor oil derivatives were associated with spherical vesicles formation, whereas serine residues bearing hydroxyl groups may be associated with the tubular vesicles.

Cleaning Efficiency of Amino-Acid Surfactants with Polyoxyethylene Ether and Isopropanol in Liquid Carbon Dioxide

Although anionic surfactants have a distinct positive influence on the removal of particulate soil, the removal of particulate soils is insufficient in CO2 compared to perchloroethylene. A series of amino-acid surfactants was selected as main surfactants to study the influence of polyoxyethylene ether and cosolvent on the cleaning effect. Glu-C12 and C16(3) gave the best cleaning results, which increased from a detergency value of 4.6 when no surfactants were used to 8.32 when surfactants were used. In all experiments, charged anionic surfactant particles were formed, which are responsible for the removal of particulate soil from fabric by electrostatic repulsion. The use of a cosolvent (Isopropanol [IPA]) had a positive effect on the removal of particulate soil when using Glu-C12 and TX-45. However, for other compounding combinations, the addition of IPA had a negative effect on particulate soil removal. Of the cosolvents investigated, IPA was the most suitable. With the polarity of the system increasing after adding IPA, the ethylene oxide groups of TX-45 were partially extended to CO2. Through the steric effects of branched methyl groups, the cleaning effect was improved.

A comparison of the self-assembly behaviour of sodium N-lauroyl sarcosinate and sodium N-lauroyl glycinate surfactants in aqueous and aqueo-organic media

Self-assembly of surfactants is influenced by various intermolecular interactions and molecular structure, which dictate packing of molecules in the aggregate and its microstructure. Hydrogen-bonding between amide groups plays a key role in the self-assembly process of N-acyl amino acid surfactants (NAAS). The self-assembly properties of two NAAS, sodium N-lauroyl sarcosinate (SLS) and sodium N-lauroyl glycinate (SLG) that differ only in the head-group structure were compared in aqueous and aqueo-organic media by using a number of methods, including surface tension fluorescence, dynamic light scattering, calorimetry, and microscopy. It was observed that aggregate formation is more favoured in SLG. Studies revealed that while SLS formed small spherical micelles, SLG produced unilamellar vesicles in pH 7 buffer above critical micelle concentration at 25 °C. The stability of SLG vesicles with respect to pH and temperature was also investigated. Furthermore, both SLG and SLS were found to gelify aquo-organic mixtures of varying composition upon heat-cool treatment. Their gelation behaviour was compared by measuring minimum gelation concentration, molecular packing, and morphology and mechanical stability of the thermoreversible gels. The difference in self-assembly behaviour in water as well as in aqueo-organic mixtures was attributed to the steric repulsion and hydrogen-bonding interaction at the head-group of the molecules.

Synthesis, chemistry, physicochemical properties and industrial applications of amino acid surfactants: A review

Surfactant use throughout mankind is extensive, from their initial applications as detergents extending to use in medicine, lubricant, cosmetics and even enhanced oil recovery. However, the image of surfactant use has in the past been tarnished by issues with low biodegradability and their synthesis from nonsustainable resources. Amino acid–based surfactants are a class of surfactants derived from a hydrophobe source coupled with simple amino acids, mixed amino acids from synthesis or from protein hydrolysates, and as such can be derived solely from renewable resources. There are several pathways for their synthesis and this allows for extensive structural diversity in this class of surfactants, resulting in widespread tuneable functionality in their physiochemical properties. This review includes the details of most of the available routes of synthesis for amino acid surfactants (AASs) and the impact of the diverse routes on their final physiochemical properties, including solubility, dispersability, toxicity and biodegradability. The diversity offered by the structural variation in AASs offers many exciting commercial opportunities for this ever-growing class of surfactants. It also includes a discussion on current and future potential uses of AASs.

Physicochemical Properties of Amino Acid Surfactants and Their Use in Dyeing with Natural Plant Dyes

Abstract Environment-friendly green amino acid surfactants were prepared by the reaction of glutamic acid with various fatty acids (C2–C14). These green amino acid surfactants have been found to exhibit good surface activities i.e. surface tension, foaming, wetting power and emulsifying ability. The critical micelle concentration (CMC) increases with an increase of the alkyl chain of amino acid surfactants. After 5 days the biodegradation of these amino acid surfactants was larger than 60% and consequently, the surfactants should be regarded as readily biodegradable. Finally, the green amino acid surfactants were added to natural plant dyes to test their applicability for dyeing wool fibers. The surfactant developed in this study will contribute to green and sustainability chemistry.

Biosafety Evaluation of Three Sodium Lauryl N‐Amino Acids Synthesized from Silk Industrial Waste in Mice

AbstractIn this study, three amino acid mixtures recovered from silk industry waste were reacted with lauryl chloride to synthesize three sodium laurel N‐amino acid surfactants. The three types of anionic surfactants are referred to as silk fibroin surfactant, silk sericin surfactant, and silkworm pupae surfactant. All three surfactants showed good surface properties. To evaluate biological safety, we added these three surfactants to the normal diet of mice for 8 weeks. Blood indices, blood lipid, antioxidant capacity (GSH‐PX, MDA, T‐AOC, and T‐SOD), and lipid metabolism key enzyme mRNA (PPAR‐γ, SREBP, FASN, and C/EBP‐α) levels in the liver were measured. No evident histopathological changes were found in the liver and kidney. The results showed no significant difference in their indexes between the surfactant‐fed and normal diet‐fed mice. Thus, the three amino acid surfactants are biologically safe and can be used in daily chemical cleaning products. These surfactants will not only help to reduce wastage of resources and damage to the environment, but also yield economic benefits to the silk industry in the future.

Binding interaction of sodium-N-dodecanoyl sarcosinate with hemoglobin and myoglobin: Physicochemical and spectroscopic studies with molecular docking analysis

The interaction of an amino acid surfactant, sodium-N-dodecanoyl sarcosinate (SDDS), with two heme proteins, hemoglobin (Hb) and myoglobin (Mb), has been studied employing various physicochemical and spectroscopic techniques like tensiometry, UV–Vis spectroscopy, steady-state fluorometry, time-resolved fluorometry, circular dichroism (CD) spectroscopy, calorimetry and stopped flow kinetics at physiological pH of 7.2 and 298K. Tensiometric and fluorometric analysis suggest that the interaction between SDDS and protein starts with the monomer form of the surfactant which produces small induced micelles. The micelles bind to protein backbone causing denaturation of the protein structure, and finally free micelles are formed on further addition of surfactant. Life-time measurements have been performed to shed light on the binding of surfactant around the tryptophan moieties present in the heme proteins. The changes in protein secondary structure induced by AAS collected from CD measurements reveals that the proteins are quite perturbed upon action of SDDS. The enthalpy change values of each stepwise interaction process have been found from isothermal titration calorimetry (ITC). The kinetics of the protein-surfactant interaction process has been studied using stopped flow technique. Quantum mechanical calculations involving density functional theory (DFT) and molecular docking analysis have been performed to highlight the interactive phenomenon between the surfactant and heme proteins. Thus the entire study shows a total inspection of an amino acid surfactant–heme protein interaction.

Lichenysin-geminal amino acid-based surfactants: Synergistic action of an unconventional antimicrobial mixture

Recently it has been demonstrated that catanionic mixtures of oppositely charged surfactants have improved physicochemical-biological properties compared to the individual components. Isotherms of mixtures of an anionic biosurfactant (lichenysin) and a cationic aminoacid surfactant (C3(LA)2) indicate a strong interaction suggesting the formation of a new “pseudo-surfactant”. The antimicrobial properties of the mixture lichenysin and C3(LA)2 M80:20, indicate a synergistic effect of the components. The mechanism of action on the bacterial envelope was assessed by flow cytometry and Transmission Electron Microscopy.

Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery

Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N⿿-dialkyl-N,N⿿-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H+ and double NCH2COO⿿ groups (generating NH+CH2COO⿿), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca2+ and double ⿿COO⿿ groups, nano-VD3-capsules with Ca2+ coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level.

Temperature-Induced Aggregate Transitions in Mixtures of Cationic Ammonium Gemini Surfactant with Anionic Glutamic Acid Surfactant in Aqueous Solution.

The aggregation behaviors of the mixtures of cationic gemini surfactant 1,4-bis(dodecyl-N,N-dimethylammonium bromide)-2,3-butanediol (C12C4(OH)2C12Br2) and anionic amino acid surfactant N-dodecanoylglutamic acid (C12Glu) in aqueous solution of pH = 10.0 have been studied. The mixture forms spherical micelles, vesicles, and wormlike micelles at 25 °C by changing mixing ratios and/or total surfactant concentration. Then these aggregates undergo a series of transitions upon increasing the temperature. Smaller spherical micelles transfer into larger vesicles, vesicles transfer into solid spherical aggregates and then into larger irregular aggregates, and entangled wormlike micelles transfer into branched wormlike micelles. Moreover, the larger irregular aggregates and branched micelles finally lead to precipitation and clouding phenomenon, respectively. All these transitions are thermally reversible, and the transition temperatures can be tuned by varying the mixing ratios and/or total concentration. These temperature-dependent aggregate transitions can be elucidated on the basis of the temperature-induced variations in the dehydration, electrostatic interaction, and hydrogen bonds of the headgroup area and in the hydrophobic interaction between the hydrocarbon chains. The results suggest that the surfactants carrying multiple binding sites will greatly improve the regulation ability and temperature sensitivity.

Extended studies on molecular interactions of SDBS and DTAB in aqueous solutions of amino acid at T = 293.15–313.15 K

The volumetric properties for this mixture of amino acid–surfactant system have already been discussed in an earlier published article, but to go further into the details on molecular interactions, different acoustical parameters viz. relative association (RA), intermolecular free length (Lf), molar sound number ([U]), specific acoustic impedance (Z), free volume (Vf), molar volume (Vm), internal pressure (πi) and molar cohesive energy (MCE) have been evaluated from the parent data of density, speed of sound and viscosity. The variation of these parameters with concentration of surfactant helps us in understanding the nature and extent of interactions present among the molecules in the mixture. The effect of amino acid concentrations on the micellization behavior of these surfactants has also been discussed through these parameters.

Synthesis of diacyl amino acid surfactant and evaluation of its potential for surfactant–polymer flooding

Diacyl amino acid surfactant was prepared using lauroyl chloride and l-lysine. The structure of the synthesized surfactant was confirmed by infrared spectroscopy and mass spectroscopy. The ultralow interfacial tension could be achieved when the diacyl amino acid surfactant is mixed with sulfonate in the presence of polymer as well as absence of polymer. Core flood experiments showed that 17.8 % additional oil could be recovered by injection of 0.3 pore volume of surfactant–polymer solution, making the total oil recovery reach 66.1 %.

Surface and Antimicrobial Properties of N-Palmitoyl Amino Acid–Based Surfactants

Synthesized sodium N-pamitoyl amino acids were evaluated for surface and antimicrobial properties and compared with sodium lauryl sulfate (SLS). Emulsion stability of the amino acid surfactants and calcium tolerance of the sodium N-palmitoyl isoleucine were better as compared to SLS. Wetting ability and foaming properties of the palmitic acid-based surfactants were inferior to SLS. N-Acyl amino acids exhibited better antibacterial activity compared to sodium salts of N-acyl amino acids and standard compounds against Staphylococcus aureus MLS-16 and Bacillus subtilis. These studies revealed that the palmitoyl amino acid surfactants can be exploited in household, skin care formulations, and industrial applications.

Binding interaction of an anionic amino acid surfactant with bovine serum albumin: physicochemical and spectroscopic investigations combined with molecular docking study

Exploration of binding interaction between anionic amino acid surfactant and BSA.