Sodium Sulfosuccinate Research Articles

Effect of Reverse Micelles Size on the Electron Transfer Reaction within the Ion Pair of Co (III)/Fe (II) Complexes

The electron transfer process between pentammineaquacobalt (III) and hexacyanoferrate (II), [Co(NH3)5H2O]3+/Fe(CN)6]4− ion pair was investigated in water/dioctyl sodium sulfosuccinate (AOT)/Isooctane reverse micelles. The study observed that the electron transfer rate depends on the size of the reverse micelles. The concentrations of Fe (II) ions were varied in different-sized (Wo) reverse micelles of Wo = [H2O]/[AOT] = 10 to 30, but the concentration of Co (III) ions was kept constant. The rate of electron transfer in the ion pair [Co(NH3)5H2O]3+/[Fe(CN)6]4− increased with decreasing size (Wo) of reverse micelles. The smallest reverse micelles Wo = 10 demonstrated the fastest electron transfer rate, and the biggest Wo = 30 reverse micelles showed the slowest electron transfer rate. The change of reaction environment and the location of the reactants in the reverse micelles due to confinement are considered the factors responsible for the results.

Pulsed Laser Ablation on Polymethylmethacrylate (PMMA) Surfaces for Capillary Driven Flows

Developing a surface modification technique that can be applied to a variety of thermoplastic polymers is of great practical importance. Laser surface treatment is one of effective ways to modify the surface property that can be used for various biomedical applications. In this research, we employed a controllable laser ablation technique on a polymethylmethacrylate (PMMA) surface that can improve the surface wetting property. The ablated hierarchical micro- and nano-structures and surfactant coating of dioctyl sulfosuccinate sodium salt induced controllable capillary driven flows. Morphology and wetting properties of laser ablated PMMA surface have been investigated from the perspective of possible applications in lateral flow assay. We also carried out an experimental investigation on controlling the flow rate and dynamics of capillary driven flow influenced by the ablated surface, channel width, aspect ratio, laser pulse step size, and viscosity of test fluids. While the capillary driven flow was found to follow the modified Lucas-Washburn dynamics, we also observed that the distance of advancing front contact line scaled by the hydraulic radius was inversely proportional to capillary number.

Integrative description of changes occurring on zebrafish embryos exposed to water-soluble crude oil components and its mixture with a chemical surfactant

The effects of crude oil spills are an ongoing problem for wildlife and human health in both marine and freshwater aquatic environments. Bioassays of model organisms are a convenient way to assess the potential risks of the substances involved in oil spills. Zebrafish embryos (ZFE) are a useful to reach a fast and detailed description of the toxicity of the pollutants, including both the components of the crude oil itself and substances that are commonly used for crude oil spill mitigation (e.g. surfactants). Here, we evaluated the survival rate, as well as histological, morphological, and proteomic changes in ZFE exposed to Water Accumulated Fraction (WAF) of light crude oil and in mixture with Dioctyl Sulfosuccinate Sodium (DOSS, e.g. CEWAF: Chemically Enhanced WAF), a surfactant that is frequently used in chemical dispersant formulations. Furthermore, we compared the hydrocarbon concentration of WAF and CEWAF of the sublethal dilution. In histological, morphological, and gene expression variables, the ZFE exposed to WAF showed less changes than those exposed to CEWAF. Proteomic changes were more dramatic in ZFE exposed to WAF, with important alterations in spliceosomal and ribosomal proteins, as well as proteins related to eye and retinal photoreceptor development and heart function. We also found that the concentration of high molecular weight hydrocarbons in water was slighly higher in presence of DOSS, but the low molecular weight hydrocarbons concentration was higher in WAF. These results provide an important starting point for identifying useful crude-oil exposure biomarkers in fish species.

Molecular Dynamics Simulation and Cryo-Electron Microscopy Investigation of AOT Surfactant Structure at the Hydrated Mica Surface

Structural properties of the anionic surfactant dioctyl sodium sulfosuccinate (AOT or Aerosol-OT) adsorbed on the mica surface were investigated by molecular dynamics simulation, including the effect of surface loading in the presence of monovalent and divalent cations. The simulations confirmed recent neutron reflectivity experiments that revealed the binding of anionic surfactant to the negatively charged surface via adsorbed cations. At low loading, cylindrical micelles formed on the surface, with sulfate head groups bound to the surface by water molecules or adsorbed cations. Cation bridging was observed in the presence of weakly hydrating monovalent cations, while sulfate groups interacted with strongly hydrating divalent cations through water bridges. The adsorbed micelle structure was confirmed experimentally with cryogenic electronic microscopy, which revealed micelles approximately 2 nm in diameter at the basal surface. At higher AOT loading, the simulations reveal adsorbed bilayers with similar surface binding mechanisms. Adsorbed micelles were slightly thicker (2.2–3.0 nm) than the corresponding bilayers (2.0–2.4 nm). Upon heating the low loading systems from 300 K to 350 K, the adsorbed micelles transformed to a more planar configuration resembling bilayers. The driving force for this transition is an increase in the number of sulfate head groups interacting directly with adsorbed cations.

Gemini Surfactant Mediated Catansomes for Enhanced Singlet Oxygen Generation of Rose Bengal and Their Phototoxicity against Cancer Cells.

Photodynamic therapy (PDT) is an innovative technique for cancer treatment with minimal side effects, based on the use of a photosensitizer, oxygen, and light. Photosensitizers (PSs) have several limitations, that may limit their clinical use, like poor solubilization, self-aggregation, and lack of specific targeting, which can be addressed with the use of nanomaterials. Herein, a unique type of catansomes (CaSs) was prepared using a gemini imidazolium-based surfactant (1,3-bis[(3-octadecyl-1-imidazolio)methyl]benzene dibromide (GBIB) and a double chain surfactant, diaoctyl sodium sulfosuccinate or Aerosol OT (AOT). The formation of CaS GBIB/AOT was optimized in various ethanol/water (E/W) solvent ratios by employing a facile, quick, and most reliable solution-solution mixing method. The CaS was characterized by dynamic light scattering (DLS) and field emission gun scanning electron microscopy (FEG-SEM) techniques. The experimental results reveal that stable CaSs with a spherical shape were obtained at lower concentration (100 μM). Rose Bengal (RB), a PS of the xanthene family, was incorporated into these prepared CaSs, as proven by fluorescence spectroscopy, UV-visible absorption spectroscopy, and confocal laser scanning microscopy. Singlet oxygen (1O2) generation studies revealed the relevant role of the E/W solvent ratio as there was a 4-fold boost in the 1O2 production for GBIB/AOT in E/W = 50:50 and around 3-fold in E/W = 30:70. Also, the GBIB-rich 80:20 fraction was more efficient in increasing the 1O2 generation as compared to the AOT rich fraction (20:80). Further, their phototoxicity was tested in a water-rich solvent ratio (E/W = 30:70) against MCF-7 cells. Upon irradiation with a 532 nm laser (50 mW) for 5 min, RB@GBIB/AOT(20:80) fraction caused 50% decrease in the metabolic activity of MCF-7 cells, and RB@GBIB/AOT(80:20) fraction produced a maximum 85% decrease in cell viability. Furthermore, the enhancement in intracellular 1O2 generation by RB@GBIB/AOT, as compared to pure RB, was confirmed with singlet oxygen sensor green (SOSG). This new type of CaS based on gemini surfactants exhibiting a large amount of 1O2 generation, holds great interest for several applications, such as use in photomedicine in future.

The surfactant Dioctyl Sodium Sulfosuccinate (DOSS) exposure causes adverse effects in embryos and adults of zebrafish (Danio rerio)

Dioctyl Sodium Sulfosuccinate (DOSS, CAS 577-11-7) is a chemical emulsifying surfactant that is widely used in the food and the cosmetic industry, and it is also the major component of the crude oil chemical dispersant Corexit™. Despite of its wide use, the studies related to its negative effect have been evaluated mainly in marine environments showing that DOSS is highly bioactive, extremely low volatile, and potential to persist in the environment longer than other dispersant components. Up to date, there is no available information of DOSS concentration in freshwater environments, little is known about its downstream fate after excretion and its effect on freshwater organisms. The objective of this study was to evaluate the effect of DOSS at different concentrations in embryos and adults of zebrafish Danio rerio in an acute-static bioassays of 96 h. The median lethal concentration in embryos was 33.3 mg/L. Malformations started to be observed at 10 mg/L. In adults, the gene expression analysis in gill tissues showed a deregulation in genes associated with the antioxidant system and the nucleotide excision repair mechanism. Additionally, Micronuclei (DNA damage) in erythrocytes, and fat degeneration in liver, hypertrophy and hyperplasia in gills, and hyaline drops in kidney tissues were also observed. In conclusion, the concentrations of DOSS evaluated here would be of health relevance to fish based on morphological alterations in embryos and changes in the gene expression profile, DNA damage and tissue impairment in adults.

The study of ultralow interfacial tension SiO2-surfactant foam for enhanced oil recovery

Surfactant selection and formulation are key factors in technological and economic success in chemically enhanced oil recovery (cEOR) applications. In this study, the silica nanoparticle (SNP) was added in an ultralow interfacial tension foam (ULIFT), called SNP-ULIFT foam, which was successfully prepared by ternary surfactant systems. The Carboxylate-based extended surfactant (Carboxylate), Dioctyl Sulfosuccinate Sodium salt (AOT), and Sodium Diphenyl Oxide Disulfonate (DODS) at a 0.48:0.48:0.04 wt ratio were conducted as the surfactant system. Remarkable results in the selected surfactant system were observed in terms of the ability to form foaming and ultralow interfacial tension (IFT) at 60 ± 2 °C with the ADNOC crude oil (Abu Dhabi National Oil Company) as model oil. The optimum salinity of the surfactant system was found at 2.5 wt% (8:2 Na:Ca by weight), indicating a minimum IFT of 0.0019 mN/m. The adsorption capacities at the optimum salinity condition of each surfactant in the mixture onto the SNP's surface were 1.4, 7.3 and 19.4 molecule/nm2 for the DODS, Carboxylate and AOT surfactants, respectively; the calculated total surfactant adsorption was 2.6 mg surfactant/mg nanoparticles. While in the presence of SNP, the surfactant adsorption of the ternary surfactant foam system onto the sand surface was significantly reduced by 16.2% at 200 psi and 60 °C when compared with the neat ULIFT foam system. It was remarkably noted that the adsorption of the surfactant onto the SNP surface could result in a reduction of surfactant adsorption onto the sand surface. The oil recovery performance in the core flood by ULIFT foam was the greatest with 43% of Original Oil in Place (OOIP), and it further increased by 13% in the presence of 200 ppm SNP. In addition, the stress and viscosity of ULIFT microemulsion significantly decreased with SNP. This suspension exhibited the most non-Newtonian behavior with shear-thinning behavior over different ranges of shear rate. Therefore, SNP-ULIFT foam with the appropriate surfactant selection was a successful method for improving oil recovery performance.

Silica nanofluid in low salinity seawater containing surfactant and polymer: Oil recovery efficiency, wettability alteration and adsorption studies

Production of crude oil from a matured oil reservoir is challenging due to the low recovery factor. Hybrid methods have demonstrated potential in oil recovery from the matured crude oil reservoir. In recent years, the low salinity water with chemicals (viz., surfactant, polymer) and nanoparticles have brought the attention of the researchers due to their ability in altering the interfacial properties of the rock-oil-water systems favorable for crude oil recovery. The current interest by industries in injection fluid (i.e., low salinity water injection) has prompted the invention of a hybrid oil recovery agent for matured crude oil reservoirs. In the current study, a novel silica-based hybrid nanofluids (NFs) of variable silica nanoparticles (NPs) concentration in low salinity seawater with anionic surfactant (AOT: dioctyl sodium sulfosuccinate) and polymer (PVP–K30: polyvinylpyrrolidone) (sometimes referred to as SMART LowSal) are used as an injection fluid in a sand-pack reactor. Oil recovery from oil saturated sand-pack reactor is observed to enhance due to NFs (hybrid) injection after secondary recovery. The characteristic study of relative permeability curves discloses that sand surface was initially water-wet and converted to strongly water-wet in the presence of NFs. A nuclear magnetic resonance (1H NMR) study reveals that adsorption of the chemical appeared on the sand surfaces, which could be the reason for wettability alteration, and thereby enhanced oil recovery. Similarly, the scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) of the sand samples before and after injection disclosed desorption of hydrocarbon from the sand surfaces after NFs injection. An additional 5–10% oil recovery is achieved after chemical flooding due to the injection of NFs. Adsorption isotherm study well agreed with the monolayer adsorption of surfactant on the sand surface.

Simultaneous Quantitation of Salt Dioctyl Sodium Sulfosuccinate (Doss) and Fingerprinting Analysis of Dispersed Oil in Aqueous Samples

Simultaneous Quantitation of Salt Dioctyl Sodium Sulfosuccinate (Doss) and Fingerprinting Analysis of Dispersed Oil in Aqueous Samples

Vesicle formation of disodium lauryl sulfosuccinate

Disodium lauryl sulfosuccinate (diSLSS) is an anionic surfactant, wherein a dodecyl chain and sodium sulfosuccinate are ester-bonded. The surfactant has two hydrophilic groups—sulfonic and carboxylic acid. The diSLSS reduced the surface tension of water to 26 mN m−1. However, an inflection point indicating the critical micelle concentration in the surface-tension curve was not observed. According to dynamic light scattering measurements, the diSLSS formed ca. 160 nm of aggregates, and its zeta potential changed from − 80 to − 55 mV in the concentration range of 0.1–15 mmol L−1. The aggregate exhibited a vesicle shape when imaged with a transmission electron microscope. In general, single-chain hydrocarbon-based surfactants rarely form vesicles in aqueous solutions. Therefore, the vesicle membranes were analyzed via small-angle X-ray scattering. The interlayer distance with the water layer for multilamellar vesicles was estimated to be 3 nm in a 15 mmol L−1 diSLSS solution. Because the molecular length of diSLSS is approximately 2.2 nm, the molecular membrane for multilamellar vesicles is considered as an alternate layer, rather than an extended bilayer structure. Additionally, the strong electrostatic repulsion between the large hydrophilic groups indicates the existence of an alternate layer. The diSLSS has the merit that vesicles can be easily formed with the one component of surfactant from low concentration to 17 mmol L-1.

Intramolecular charge transfer of coumarin dyes confined in methanol-in-oil reverse micelles

The reverse micelles (RMs) of bis(2-ethylhexyl)sulfosuccinate sodium salt (AOT) are considered as a model system for the molecular dynamics investigation of small chromophores, where the micelle-size-dependent dynamics are interpreted as the unique solvent properties in the core of RMs. The sizes of RMs are practically proportional to the molar ratio between polar solvent and surfactant. However, the formation of RMs with nonaqueous polar solvents methanol or acetonitrile is not clearly understood yet. In this work, we have shown that the formation of RMs with methanol core depends strongly on the concentration of surfactant AOT by the experimental evidence of the absorption, emission, and Raman spectroscopic measurements. In addition, the intramolecular charge transfer dynamics of coumarin 481 (C481) and coumarin 153 in methanol RMs were investigated by steady-state and time-resolved electronic spectroscopy, where the differences of the excited-state dynamics in the RMs are understood as the effect of the molecular rotation of diethylamino group of C481.

Synthesis, Characterization and Sorption Ability of Epoxy Resin-Based Sorbents with Amine Groups.

Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). Triethylenetetramine (TETA) was applied as a cross-linking agent in the amounts of 1 g (6.67 wt %), 1.5 g (10 wt %), and 2 g (13.33 wt %). The use of a compound with amino groups allows for the simultaneous functionalization of the obtained material. The reaction was carried out in an environment of ethylene glycol, with the addition of a porophore solvent (toluene) and bis(2-ethylhexyl)sulfosuccinate sodium salt (S). The attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) revealed the existence of a strong band in the 828–826 cm−1 range corresponding to the second-order amine group, which indicates their incorporation into the epoxy structure. The glass transition and decomposition temperatures of the resins decreased with the increasing amounts of amine in the material. The thermogravimetry (TGA) analysis demonstrated that all products are thermally stable up to 340 °C. The surface morphology and microstructural properties of the obtained sorbents were determined using scanning electron microscopy (SEM) images and showed an irregular star shape, with dimensions ranging from 400 to 1000 µm. The adsorption capacities of Ep5-TETA1, Ep5-TETA1.5, Ep5-TETA2 and Ep5-TETA1.5 + S for AV1 evaluated during batch experiments were found to be 2.92, 3.76, 7.90 and 3.30 mg/g, respectively.

Evaluation of interfacial properties due to the effect of dispersing agents on Brazilian medium crude oil

Through the Deepwater Horizon oil spill accident in 2010, around 7.000 m3 of chemical dispersants were applied to a subsea blowout until the release of crude oil to the environment was ended. Since then, chemical dispersion has become one of the major capabilities for oil spill response around the world. Because of this relevancy, this article aims at expanding the current knowledge of interfacial phenomena related to chemical dispersants application at oil spills, with focus in a representative Brazilian crude oil which has never before been assessed with this purpose. Therefore, first this oil was characterized, and a weathering process was simulated by preparing samples with different distillation and emulsification features. After this, samples dispersion effectiveness’s was evaluated using a low-energy method and a commercial product: Corexit EC9500A. Because only the fresh oil condition result was considered satisfactory, its interfacial behavior was investigated with more details. First, the interfacial tension was investigated as a function of water salinity and dispersant concentration. Dynamic interfacial tension was measured individually for dioctyl sodium sulfosuccinate (DOSS), Tween 80 and Span 80, the main components many of current commercial chemical dispersants. Finally, the partition coefficients and dilational rheology parameters were evaluated for different concentrations and conditions. The individual surfactants behavior assessment results published in this paper will allow further comprehension of the interfacial behavior in this specific oil-water system, thus providing data for future researches aimed at optimizing chemical dispersion effectiveness for similar crudes produced in maritime sea basins of Brazil and also supporting regulators in the decision-making process necessary for protecting environmental resources during an oil spill. A future paper will explore mathematical correlations between chemical dispersion effectiveness and surfactants’ mixture ratios, emulsions’ stabilities and other interfacial properties of some Brazilian crude oils.

In vitro study on the immunomodulatory effects of differently functionalized silver nanoparticles on human peripheral blood mononuclear cells.

The interaction of silver nanoparticles (AgNPs) with the immune system has not yet been sufficiently elucidated even though they belong to the most investigated and exploited group of nanomaterials. This study aimed to evaluate immunomodulatory effect of four different AgNPs on human peripheral blood mononuclear cells (hPBMCs). Fresh hPBMCs were exposed to the small sized (~ 10 nm) AgNPs immediately after isolation from the whole blood of healthy volunteers. The study considered coating-, time- and dose-dependent response of hPBMSc and stimulation of both early and intermediate activation of lymphocytes and monocytes using flow cytometry. The AgNPs differed in surface charge and were stabilised with polyvinyl pyrrolidone (PVP), poly-L-lysine (PLL), bis(2-ethylhexyl) sulfosuccinate sodium (AOT) or blood serum albumin (BSA). Response of hPBMCs to coating agents and ionic Ag form was evaluated to distinguish their effect from the AgNPs action as they may be released from the nanosurface. There was no significant effect of any tested AgNPs on relative count of hPBMCs subpopulations. The T-cells and monocytes were not activated after treatment with AgNPs, but the highest concentration of PLL- and BSA-AgNPs decreased density of CD4 and CD8 markers on T-helper and T-cytotoxic cells, respectively. The same AgNPs activated B- and NK-cells. Ionic Ag activated T-, B- and NK-cells, but at very higher concentration, whereas only PLL exhibited immunomodulatory activity. This study evidenced immunomodulatory activity of AgNPs that may be fine-tuned by the design of their surface functionalization.Graphic abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s00775-021-01898-0.

Tuning the Mechanical and Thermal Properties of Hydroxypropyl Methylcellulose Cryogels with the Aid of Surfactants.

The mechanical and thermal properties of cryogels depend on their microstructure. In this study, the microstructure of hydroxypropyl methylcellulose (HPMC) cryogels was modified by the addition of ionic (bis (2-ethylhexyl) sodium sulfosuccinate, AOT) and non-ionic (Kolliphor® EL) surfactants to the precursor hydrogels (30 g/L). The surfactant concentrations varied from 0.2 mmol/L to 3.0 mmol/L. All of the hydrogels presented viscous behavior (G″ > G′). Hydrogels containing AOT (c > 2.0 mmol/L) led to cryogels with the lowest compressive modulus (13 ± 1 kPa), the highest specific surface area (2.31 m2/g), the lowest thermal conductivity (0.030 W/(m·°C)), and less hygroscopic walls. The addition of Kolliphor® EL to the hydrogels yielded the stiffest cryogels (320 ± 32 kPa) with the lowest specific surface area (1.11 m2/g) and the highest thermal conductivity (0.055 W/(m·°C)). Density functional theory (DFT) calculations indicated an interaction energy of −31.8 kcal/mol due to the interaction between the AOT sulfonate group and the HPMC hydroxyl group and the hydrogen bond between the AOT carbonyl group and the HPMC hydroxyl group. The interaction energy between the HPMC hydroxyl group and the Kolliphor® EL hydroxyl group was calculated as −7.91 kcal/mol. A model was proposed to describe the effects of AOT or Kolliphor® EL on the microstructures and the mechanical/thermal properties of HPMC cryogels.

Evidence of formation of dye–surfactant ion pair micelle in the anionic surfactant mediated alkaline fading of methyl violet carbocation

AbstractIn the submicellar solution of anionic surfactants sodium dodecyl sulfate (SDS) and dioctyl sodium sulfosuccinate (AOT), the alkaline fading of methyl violet (MV+) carbocation has been studied spectrophotometrically in the temperature range 293–308 K. The interaction behavior of the dye carbocation with the anionic surfactant and the observed submicellar rate retardation is consistent with the ion pair and subsequent ion‐pair micelle formation. The change in the spectral pattern along with a change in the peak intensity and shoulder intensity with increasing surfactant concentrations indicates the shifting of the equilibrium between the helical and distorted helical isomers of MV+ owing to the existence of dye–surfactant ion pair, ion‐pair micelles, and dye‐embedded micelles. This dynamic dye–surfactant ion‐ion interaction has been corroborated by the tensiometric studies. The decrease in the fading rate and the change in the spectral pattern in the presence of anion, especially I–, support the existence of the dye–anion interaction. The premicellar rate inhibition and the corresponding interaction have been accounted for by the use of two kinetic models namely, Olson–Simonson and Piszkiewicz cooperativity models. The cooperativity index value suggested a 1:1 dye–surfactant association in both the surfactants. The ratio of the concentration of the premicellar complex and the free dye cation indicates appreciable binding. The kinetic and thermodynamic parameters associated with the dye–surfactant complex have been explained in terms of dye–surfactant, dye–water, and surfactant–water interactions.

Effects of AOT reverse micelle extraction on structure and emulsifying properties of soybean protein

AbstractThe present study aimed to investigate the forward and backward extraction efficiency, structure, and emulsifying properties of soybean proteins obtained through bis (2‐ethylhexyl) sulfosuccinate sodium salt (AOT) reverse micelle, as well as their relationship. The results showed that the extraction efficiency was the highest with the forward extraction time of 25 min, pH of 3.0, temperature of 45°C, KCl concentration of 0.0 mol L−1, and the backward extraction time of 10 min, pH of 4.0, temperature of 30°C, KCl concentration of 0.5 mol L−1. Significant changes in the secondary structure and fluorescence intensity of soybean protein after AOT reverse micelle extraction were observed. More β‐sheet structure and higher fluorescence intensity corresponded to the higher emulsion stability of soybean protein. The results indicated that reverse micelle extraction shows great application in food industry.

Alterations induced in the micellization behavior of dioctyl sodium sulfosuccinate in the presence of imidazolium-based surface-active ionic liquids in aqueous medium

The present work describes the effect of 1-nonyl-3-methylimidazolium bromide [C9mim][Br] and 1-dodecyl-3-methylimidazolium bromide [C12mim][Br] on aggregation behavior of anionic surfactant dioctyl sodium sulfosuccinate (NaAOT) in aqueous medium by employing different techniques such as conductivity measurement, UV–Visible spectroscopy and FT-IR spectroscopy. The conductivity data of anionic surfactant in the aqueous solution of surface-active ionic liquids is taken experimentally in the temperature range from 293.15 to 308.15 K with the interval of 5 K at various concentrations that is, (0.04, 0.08, 0.12, and 0.16) wt.% of both the SAILs. The critical micelle concentration (CMC) of NaAOT is detected to alter in the presence of both the SAILs. Temperature dependence of CMC obtained from conductivity measurements is utilized to evaluate various thermodynamic parameters of micellization such as, standard free energy of micellization (), standard enthalpy of micellization (), and standard entropy of micellization (). The UV–Visible spectroscopic study is utilized to confirm CMC values obtained from conductivity measurements, which are found to be in good agreement. FT-IR Spectra are recorded to analyze the structural changes that prevailed in both systems.

Kinetics of Non-Enzymatic Synthesis of Dipeptide Cbz-Phe-Leu with AOT Reversed Micelles

The non-enzymatic synthesis of N-benzyloxycarbonyl-L-phenylalanyl-L-leucine (Cbz-Phe-Leu) from lipophilic N-benzyloxycarbonyl-L-phenylalanine (Cbz-Phe) and hydrophilic L-leucine (Leu), by N, N’-dicyclohexylcarbodiimide (DCC) as a condensing agent, was carried out using a reversed micellar system composed of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) as a surfactant and isooctane. We successfully synthesized Cbz-Phe-Leu in a short time and investigated the effects of its operational conditions, the DCC concentration, w0, and the pH on the kinetic parameters and the maximum yields. For dipeptide synthesis, we had to add an excess of DCC with the substrates because of the side reactions of Cbz-Phe. From the pH dependency of the reactivity, a partially cationic form of Leu was better for a synthesis reaction because of the enrichment of Leu at the interface by anionic AOT. The optimum water content on the dipeptide synthesis was w0 = 28 due to the competition of the peptide synthesis and the side reactions. The maximum yield of Cbz-Phe-Leu was 0.565 at 80 h under optimum experimental conditions.

Bioremediation of phenolic pollutant bisphenol A using optimized reverse micelles system of Trametes versicolor laccase in non-aqueous environment.

The online version contains supplementary material available at 10.1007/s13205-021-02842-4.