Sodium P-toluenesulfonate Research Articles

Stabilizing zinc anodes by a solvation sheath modification with toluenesulfonate additive

As an advanced electrochemical energy storage device, aqueous zinc-ion batteries offer high theoretical capacity and energy density, employing water-based electrolytes to reduce fire and explosion risks. However, zinc tends to form dendrites during charge-discharge processes, leading to reduced electrode surface area and shortened cycling lifespan. In this study, we propose the use of a commonly used and cost-effective additive, sodium p-toluenesulfonate (OTM), to stabilize zinc anodes. Experimental and theoretical simulations demonstrate that OTM can enter the solvation sheath of Zn2+, reduce the activity of nearby H2O molecules, facilitate uniform Zn2+ deposition, and suppress zinc dendrite formation. Therefore, Zn//Zn symmetric batteries utilizing ZnSO4 (ZSO) electrolytes containing OTM achieved outstanding long-term performance exceeding 1700 h at 1 mA cm−2, significantly surpassing those employing ZSO electrolytes. Additionally, Zn//VO2 full batteries with OTM additives exhibited enhanced cycling stability and an initial discharge capacity of 180 mAh g−1 at 3 A g−1, demonstrating its superior application potential.

Simultaneous regulation of the solvation shell and electrode interface via a multifunctional and low-cost additive enabling long-life aqueous Zn metal batteries

Zinc metal batteries have great potential for energy storage applications in smart grids. However, the Zn metal anode presents significant challenges, such as the irrepressible growth of zinc dendrites on the anode’s surface, the accumulation of inert products, and the hydrogen evolution reaction. These issues can lead to the decreased cycling stability of the anode. To solve these problems, we developed a method of adding sodium p-toluenesulfonate to the electrolyte to protect the zinc metal anode. Density functional theory calculations show that the −SO3 functional group in sodium p-toluenesulfonate can alter the solvation structure of Zn2+ and adsorb onto the surface of the Zn metal anode. Thus, the Zn||Zn symmetric cell could be cycled stably for over 2000 h, whereas the Zn||Cu half-cell could be cycled stably for over 5000 cycles, with an average Coulombic efficiency of 99.87 %. The Zn||I2 full cell could be cycled stably for 10,000 cycles under test conditions of 1A/g, and the capacity retention rate was 95.49 %. This study provides insights into the use of additives in the electrolytes of zinc metal batteries.

Enhancing Optical and Thermal Stability of Blue-Emitting Perovskite Nanocrystals through Surface Passivation with Sulfonate or Sulfonic Acid Ligands.

This study aims to enhance the optical and thermal properties of cesium-based perovskite nanocrystals (NCs) through surface passivation with organic sulfonate (or sulfonic acid) ligands. Four different phenylated ligands, including sodium β-styrenesulfonate (SbSS), sodium benzenesulfonate (SBS), sodium p-toluenesulfonate (SPTS), and 4-dodecylbenzenesulfonic acid (DBSA), were employed to modify blue-emitting CsPbBr1.5Cl1.5 perovskite NCs, resulting in improved size uniformity and surface functionalization. Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the successful anchoring of sulfonate or sulfonic acid ligands on the surface of perovskite NCs. Moreover, the photoluminescence quantum yield increased from 32% of the original perovskite NCs to 63% of the SPTS-modified ones due to effective surface passivation. Time-resolved photoluminescence decay measurements revealed extended PL lifetimes for ligand-modified NCs, indicative of reduced nonradiative recombination. Thermal stability studies demonstrated that the SPTS-modified NCs retained nearly 80% of the initial PL intensity when heated at 60 °C for 10 min, surpassing the performance of the original NCs. These findings emphasize the optical and thermal stability enhancement of cesium-based perovskite NCs through surface passivation with suitable sulfonate ligands.

Ultrasound assisted hydrotropic extraction of polyphenols from green tea leaves in aqueous media

A green approach of combining hydrotrope assisted extraction with ultrasound was adopted to extract the polyphenols from tea leaves. This process significantly reduced extraction time and solvent quantity, while enhancing the quality of the final product. Sodium cumenesulfonate (NaCuS), sodium p-toluenesulfonate (NaPTS) and sodium xylenesulfonate (NaXS) were chosen for solubilizing tea polyphenols. Among the hydrotropes used, NaCuS proved to be efficient particularly in solubilizing tea polyphenols. The extraction process was thoroughly studied by varying factors such as the solid to solvent ratio (S/N), ultrasonic duration and temperature. Comprehensive solubility studies of polyphenols were conducted across different solvents, pH levels, temperatures, treatment durations and solid loadings. To optimize the experimental parameters, a central composite design (CCD) of response surface methodology (RSM) was employed. The results demonstrated that a polyphenol extraction efficiency of 68.429% was achieved at a solid to solvent ratio of 0.05, ultrasonic time of 3.2 h and temperature of 49.9 °C. This research firmly established the effectiveness of ultrasound assisted extraction for obtaining polyphenols from green tea in a highly efficient manner.

Smart Implant with Bacteria Monitoring and Killing Ability for Orthopedic Applications.

Bacterial infections around implants constitute a significant cause of implant failures. Early recognition of bacterial adhesion is an essential factor in preventing implant infections. Therefore, an implant capable of detecting and disinfecting initial bacterial adhesion is required. This study reports on the development of an intelligent solution for this issue. We developed an implant integrated with a biosensor electrode based on alternating current (AC) impedance technology to monitor the early growth process of Escherichia coli (E. coli) and its elimination. The biosensor electrode was fabricated by coating polypyrrole (PPy) doped with sodium p-toluenesulfonate (TSONa) on titanium (Ti) surfaces. Monitoring the change in resistance using electrochemical impedance spectroscopy (EIS), combined with an equivalent circuit model (ECM), enables the monitoring of the early adhesion of E. coli. The correlation with the classical optical density (OD) monitoring value reached 0.989. Subsequently, the eradication of bacteria on the electrode surface was achieved by applying different voltages to E. coli cultured on the electrode surface, which caused damage to E. coli. Furthermore, in vitro cellular experiments showed that the PPy coating has good biocompatibility and can promote bone differentiation.

Dopant Engineering of Flexible MNPs/TPU/PPy Core-Shell Films for Controllable Electromagnetic Interference Shielding.

Intrinsically conductive polymers have attracted much attention in the electromagnetic interference (EMI) shielding field because of their high conductivity and favorable flexibility. Delocalized π-electrons migrating along the conjugated long-chain structures can form a current. Based on this special conductive mechanism, the doping process significantly influences the conductivity and EMI shielding efficiency (SE). However, it is challenging to investigate the influence of the doping process on EMI shielding performance, which would enable the optimization of dopant selection. In this study, dopant engineering was explored for controllable conductivity, EMI SE, and mechanical properties. Polypyrrole (PPy) doped with various dopants serves as a conductive coating owing to its adjustable conductivity and abundant functional groups. Elastic thermoplastic polyurethane was chosen as the porous framework because of its high tensile strength, and magnetic nanoparticles supplied the magnetic loss in the 3D network. Eventually, the composite film showed the best properties when PPy was doped with sodium p-toluenesulfonate. The film exhibited an average SE of 26.3 dB in the X band and a specific SE of 1563.17 dB cm2 g-1 with a thickness of merely 0.2 mm. This film withstood a tensile stress of 16.0 MPa, while the breaking elongation ratio reached 538.0%. After 10,000 cyclic bending, 92.3% of the EMI shielding property was retained. In summary, this study highlights the most suitable dopant for EMI shielding applications and provides a prospective alternative for advanced, flexible, and smart devices.

Extraction of mangiferin and pectin from mango peels using process intensified tactic: A step towards waste valorization

Simultaneous extraction of mangiferin and pectin from the waste mango peels was attempted with the aim of reducing the number of processing steps, minimizing the operation time and avoiding the requirement of harsh acids. Microwave-assisted extraction has been employed along with different hydrotropes (sodium cumene sulfonate, sodium salicylate, and sodium p-toluene sulfonate) and methanol with varying concentrations. The highest yield of mangiferin (10.43 mg/g) was attained using sodium cumene sulfonate at 80 W microwave power, 10 min time, 0.5 M concentration, 80 °C temperature and 1:50 g/mL solid-liquid ratio. The mangiferin recovery was 20 % higher using hydrotropic solution in comparison to methanol (50 %, v/v). The hydrotropes have concurrently extracted pectin (25.38 %, w/w), which was not possible using methanol. Thus, the incorporation of hydrotropes has led to the avoidance of acidic solution for the recovery of pectin. Pectin has a higher methoxy content (∼ 74 % degree of esterification) and a higher percentage of D-galacturonic acid. The extraction time was further reduced in the range of 50–70 % by embedding sonication with microwave-assisted extraction. Moreover, the extract has exhibited good antioxidant activities (> 70 % DPPH and> 90 % ABTS). A symbiotic effect of hydrotrope, microwave and sonication has resulted in the simultaneous extraction of mangiferin and pectin along-with better processing conditions thereby providing a sustainable option which can be explored at a higher scale. In addition, the present study has presented a judicious utilization of mango waste.

A novel triple responsive smart fluid for tight oil fracturing-oil expulsion integration

The traditional multi-process to enhance tight oil recovery based on fracturing and huff-n-puff has obvious deficiencies, such as low recovery efficiency, rapid production decline, high cost, and complexity, etc. Therefore, a new technology, the so-called fracturing-oil expulsion integration, which does not need flowback after fracturing while making full use of the fracturing energy and gel breaking fluids, are needed to enable efficient exploitation of tight oil. A novel triple-responsive smart fluid based on “pseudo-Gemini” zwitterionic viscoelastic surfactant (VES) consisting of N-erucylamidopropyl-N,N-dimethyl-3-ammonio-2-hydroxy-1-propane-sulfonate (EHSB), N,N,N′,N′-tetramethyl-1,3-propanediamine (TMEDA) and sodium p-toluenesulfonate (NaPts), is developed. Then, the rheology of smart fluid is systematically studied at varying conditions (CO2, temperature and pressure). Moreover, the mechanism of triple-response is discussed in detail. Finally, a series of fracturing and spontaneous imbibition performances are systematically investigated. The smart fluid shows excellent CO2-, thermal-, and pressure-triple responsive behavior. It can meet the technical requirement of tight oil fracturing construction at 140 °C in the presence of 3.5 MPa CO2. The gel breaking fluid shows excellent spontaneous imbibition oil expulsion (∼40%), salt resistance (1.2 × 104 mg/L Na+), temperature resistance (140 °C) and aging stability (30 days).

Phosphine-Functionalized Core-Crosslinked Micelles and Nanogels with an Anionic Poly(styrenesulfonate) Shell: Synthesis, Rhodium(I) Coordination and Aqueous Biphasic Hydrogenation Catalysis.

Stable latexes containing unimolecular amphiphilic core-shell star-block polymers with a triphenylphosphine(TPP)-functionalized hydrophobic core and an outer hydrophilic shell based on anionic styrenesulfonate monomers have been synthesized in a convergent three-step strategy by reversible addition-fragmentation chain-transfer (RAFT) polymerization, loaded with [RhCl(COD)]2 and applied to the aqueous biphasic hydrogenation of styrene. When the outer shell contains sodium styrenesulfonate homopolymer blocks, treatment with a toluene solution of [RhCl(COD)]2 led to undesired polymer coagulation. Investigation of the interactions of [RhCl(COD)]2 and [RhCl(COD)(PPh3)] with smaller structural models of the polymer shell functions, namely sodium p-toluenesulfonate, sodium styrenesulfonate, and a poly(sodium styrenesulfonate) homopolymer in a biphasic toluene/water medium points to the presence of equilibrated Rh-sulfonate interactions as the cause of coagulation by inter-particle cross-linking. Modification of the hydrophilic shell to a statistical copolymer of sodium styrenesulfonate and poly(ethylene oxide) methyl ether methacrylate (PEOMA) in a 20:80 ratio allowed particle loading with the generation of core-anchored [RhCl(COD)TPP] complexes. These Rh-loaded latexes efficiently catalyze the aqueous biphasic hydrogenation of neat styrene as a benchmark reaction. The catalytic phase could be recovered and recycled, although the performances in terms of catalyst leaching and activity evolution during recycles are inferior to those of equivalent nanoreactors based on neutral or polycationic outer shells.

Exploring synergistic fire suppression of siloxane-glycoside firefighting foam using sulfonated hydrotrope additives to alter surfactant aggregation in solution

Synergism between siloxane 502W and alkylpolyglycoside Glucopon 225DK surfactants in a mixture has resulted in a foam with firefighting potential. This synergism is not well understood, therefore additives were utilized to alter performance. Hydrotropes sodium benzene sulfonate and sodium p-toluene sulfonate were introduced to alter micelle size while keeping other solution properties constant and their effects were assessed for the individual surfactants and the mixture. Solution properties including micelle size (via dynamic light scattering) were measured along with the heptane vapor transport rate through a foam layer, foam expansion ratio, and fire extinction performance on a 19 cm heptane pool fire using a CO2 absorption measurement. Increased micelle size with hydrotrope addition did not directly correlate with improved fire suppression. Hydrotropes destabilized G225 aggregation, possibly due to G225 inter-surfactant hydrogen bonding potentials, which is limited for 502W. Hydrotropes inhibit the mixture G225 contribution while 502W remains. 502W is less effective individually, resulting in increased fire extinction times for the mixture with hydrotropes. Previously reported mixture synergism may be related to collaboration of individual surfactant contributions. Surfactant roles and inter-surfactant hydrogen bonding potentials are supported by the collected data, but have not been directly measured and require further evaluation.

Electrochemical Fabrication and Characterization of Organic Electrochemical Transistors Using poly(3,4-ethylenedioxythiophene) with Various Counterions

Organic electrochemical transistors (OECTs) are promising bioelectronic devices, especially because of their ability to transport charge both ionically and electronically. Conductive polymers are typically used as the active materials of OECTs. Crosslinked, cast, and dried films of commercially available poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) suspensions are commonly and widely used for OECTs so far. Electrochemical polymerization of PEDOT from 3,4-ethylenedioxythiophene (EDOT) monomer can also be used to fabricate OECTs; however, this approach has not been investigated in as much detail. In particular, the role of various counterions that can be incorporated into the PEDOT films of OECTs has not been systematically studied. Here, we report the electrochemical fabrication and characterization of OECTs using PEDOT with several different counterion salts including lithium perchlorate (LiClO4), sodium p-toluene sulfonate (pTS), and poly(sodium 4-styrene sulfonate) (PSS). We found that the characteristic dimensions of PEDOT films deposited on the electrodes could be precisely controlled by total charge density, with a nominal thickness of about one micron requiring a current density of about 0.6 C/cm2 regardless of the choice of counterion. The films with the PSS counterion were relatively smooth, while PEDOT films prepared with the pTS and LiClO4 were much rougher due to the sizes of counterions. The PEDOT films with pTS and PSS grew along the substrate surface (in-plane direction) much faster than with LiClO4. The maximum transconductance (gm) of a PEDOT OECT was 46 mS with pTS as the counterion with the high on-current level (>10 mA) based on the large channel area. These results provide an effective and efficient way to fabricate OECTs with various monomers and additives as active materials in order to modify the device characteristics for further applications.

A novel property enhancer of clean fracturing fluids: Deep eutectic solvents

Fracturing fluid properties are closely related to the oil recovery of unconventional reservoirs. In the meantime, deep eutectic solvents (DESs) have provided a new method to improve the properties of clean fracturing fluids (CFFs) due to their low-toxicity raw materials and mild synthesis conditions. In this work, DESs were developed as the enhancers to intensify rheological characteristics and spontaneous imbibition performance of CFFs. The adjustment of hydrogen bond donors (HBDs) can effectively regulate the rheological characteristics of CFFs. The DES composed of choline chloride (ChCl) and malonic acid (MA) can significantly increase the viscosity of CFF from 38.1 mPa·s to 60.1 mPa·s, the shear resistance and viscoelastic modulus were both improved. The interactions between HBDs and sodium p-toluenesulfonate (TsONa) anion has an influence on the electrostatic shielding of TsONa anion for OAHSB, which further determines the strength of micelle networks. For the spontaneous imbibition of CFFs, DESs improved the imbibition efficiency from 33.0% in 98 h to 40.1–47.2% in 78–90 h through the reduction of oil–water interfacial tension and oil viscosity, change of oil-contacting surface wettability and the increase of core porosity and permeability. The DESs here provide a novel strategy to enhance CFF properties in an environmentally friendly and efficient way.

The effect and enhancement mechanism of hydrophobic interaction and electrostatic interaction on zwitterionic wormlike micelles

The effects of hydrophobic interaction and electrostatic interaction on the structure of zwitterionic wormlike micelles (WLMs) were studied. The change of the hydrocarbon chain length and addition of cetyl trimethyl ammonium chloride (CTAC) were employed to explore the effect of hydrophobic interaction and electrostatic interaction on the wormlike micelles constructed by zwitterionic viscoelastic surfactants and sodium p-toluene sulfonate (NaPts). The experimental results show that increasing hydrocarbon chain length of zwitterionic surfactant and the addition of CTAC can increase the viscoelasticity and zero-shear viscosity of the system. The calculated length of wormlike micelles also increases. This shows that the enhancement of hydrophobic interaction and electrostatic interaction can promote the growth and entanglement of wormlike micelles. In addition, scanning electron microscope (SEM) images confirmed that CTAC makes the connection between the zwitterionic micellar layer closer. This is undoubtedly beneficial to the growth of micellar structure. Finally, this work explores the enhancement mechanism of the hydrophobic interaction and electrostatic interaction on the micelle structure.

Dual sulfur-doped sites boost potassium storage in carbon nanosheets derived from low-cost sulfonate

• Dual S-doped carbon sheets are obtained by one-step low-cost pyrolysis. • C-S bonds and ultrafine sulfate are tailored on enlarged d-spacing carbon sheets. • High-capacity, long-life and high-rate K-ion battery is obtained. • Ex-situ XPS and capacity-contribution analysis reveal storage mechanism. As a new energy storage system, K-ion batteries (KIBs) have the advantages of low price and competitive high energy density. However, due to the large radius of K + , in the process of intercalation/deintercalation, the traditional carbon anode materials usually display insufficient cycle life and poor rate performance in KIBs. In this work, inexpensive and widely-sourced sodium p-toluenesulfonate (CH 3 C 6 H 4 SO 3 Na) is used as raw material to synthesize dual sulfur-doped carbon nanosheets (DS-CN) by a simple one-step carbonization method. The nanosheets possess an enlarged interlayer distance (4.25 Å) which allows large K + to intercalate. C-S bonds and the embedded ultrafine sulfate provide active sites to enhance capacity and accelerate kinetics. Moreover, a high S/O ratio would reduce the irreversible reactions caused by oxygen functional groups. The high reversible specific capacity (331.9 mA h g −1 at 50 mA g −1 ), good rate performance (165.3 mA h g −1 at 1000 mA g −1 ) and long cycle stability (0.011% capacity decay per cycle) are attributed to the multiple synergistic effects of enlarged layer spacing, reaction between C-S bonds and K + , as well as more active -C-SO 2 - bonds, as confirmed by ex-situ XPS and electrochemical analysis. Our work shows a feasible and effective way to develop low-cost, high-performance carbon anode materials for KIBs.

Surface mechanism and optimization of catalytic ozonation with CoxFe oxides as catalyst for degradation of sodium p-toluenesulfonate in water.

In this study, the removals of sodium p-toluenesulfonate (NaTSA) by catalytic ozonation with two different cobalt-iron compounds, CoxFe oxides prepared by co-precipitation/calcination (CPO) and CoxFe oxides prepared by direct calcination (DCO), as the catalysts, had a difference of about 12%. It was found that the CPO surface contained active type c water, which was generally adsorbed on the oxygen vacancy. The test of oxygen temperature-programmed desorption (O2-TPD) showed that the surface of CPO was rich in oxygen vacancy. Through the electrochemical oxygen evolution reaction (OER) detection, a pair of Co valence redox peaks were detected from the CV curves, and the results of XPS test showed the replacement of octahedral Co3+ with Fe3 + in the Co3O4 during preparation of CPO. The enriched oxygen vacancy could be used as active sites for ozone adsorption and improve the charge transfer capacity. The number of hydroxyl radicals was detected by electron spin resonance (EPR) and it indicated that CPO contained more hydroxyl radicals, so it had higher effect in catalytic ozonation for organic pollutant degradation. In this paper, the relationship between oxygen vacancy and reactive center in the microstructure of the catalysts was established to discuss their working mechanism. The influence of the initial pH value, catalyst dosage, and ozone concentration on the removal of NaTSA was investigated by response surface design, and the optimal experimental conditions were predicted and verified.

Modulation of micellization behavior of imidazolium based surface active ionic liquids by aromatic anions in aqueous medium

Surface active ionic liquids (SAILs) represent a class of ionic surfactants that many times display better surface-active properties as compared to conventional ionic surfactants. The micellization of SAILs can be further tailored by the addition of salts, and aromatic salts comprising hydrotropic anions have never been explored for altering the micellization of SAILs in low concentration range. Considering this, we have investigated the effect of addition of three aromatic salts i.e. Sodium 4-hydroxy benzenesulfonate, sodium benzenesulfonate, and sodium p-toluenesulfonate on the micellization of 1-dodecyl-3-methylimidazolium chloride, [C12mim][Cl] and its amide functionalized counterpart, 3-(2-(dodecylamino)−2-oxoethyl)−1-methyl-1H-imidazol-3-ium chloride, [C12Amim][Cl]. The surface-active behavior of SAILs has been investigated by tensiometry, whereas micellization in bulk has been probed through conductivity, steady-state fluorescence, dynamic light scattering (DLS) and zeta-potential measurements. The possible location of aromatic anions adsorbed on the micellar surface has been probed using 1H NMR measurements. Isothermal titration calorimetry has been utilized to gain insights into the thermodynamic aspects of micellization. The inferences gained from different techniques have been correlated and found to be in good agreement with each other. It has been observed that the functionalization of alkyl chain length of SAIL along with relative hydrophobicity and bulkiness of the aromatic anions control the characteristic properties of micellization.

Interfacial properties of novel surfactants based on maleic and succinic acid for potential application in personal care

Hemiesters and Hemiamides of maleic and succinic acid viz. sodium lauryl succinate (C12SE), sodium lauryl maleate (C12ME), sodium lauryl succinamide (C12SA), sodium lauryl maleamide (C12MA), sodium hexadecyl succinate (C16SE) and sodium hexadecyl maleate (C16ME) were synthesized and investigated as surfactants in the pure water and aqueous hydrotrope [sodium p-toluene sulfonate (NaPTs)] solution. The chemical structures of the prepared surfactants were established by FTIR and 1H NMR spectroscopy. The surface tension measurements depicted low CMC and a high adsorption efficiency (pC20) which is highly beneficial for creating personal care formulations. The dynamic light scattering (DLS) technique indicated the formation of larger micelles which was important for skin care as larger micelles cannot penetrate the skin layer. Moreover, these surfactants depicted good foamability and stability attributed to faster monomer adsorption and small bubble size which was preferred for cleansing application. Additionally, low protein/lipid solubilization by these surfactants indicated its mild behaviour on skin as compared to other commonly used conventional anionic [sodium lauryl sulfate (SLS)], zwitterionic [cocamidopropyl betaine (CAPB)] and nonionic [decyl glucoside (DG)] surfactants. Viscosity measurements suggested decent thickening ability of surfactants in the presence of co-surfactant like lauramine oxide. Basis of all the properties discussed, these novel hemiesters and hemiamides seem promising as surfactants for improving various characteristics in potential personal care formulations.

‘In water’ exploration of Alpinia zerumbet-fabricated CuO NPs in the presence of NaPTS at room temperature: green synthesis of 1,8-dioxooctahydroxanthene derivatives

The biogenic synthesis of copper oxide nanoparticles (CuO NPs) from the leaf extract of Alpinia zerumbet was investigated in this protocol. The basic nature of A. zerumbet leaf extract helps in CuO NPs synthesis. The catalytic activity of A. zerumbet-fabricated CuO NPs is explored in water at room temperature only in the presence of NaPTS hydrotrope. The green catalytic protocol is investigated via synthesis of 1,8-dioxooctahydroxanthene. The biogenic leaf extract fabricated CuO NPs are efficiently reactive, stable and recyclable in aqueous solution of sodium p-toluenesulfonate (NaPTS) hydrotrope. CuO/NaPTS proved to be the best catalytic system as synergistic nanotrope in terms of yield and time of reaction in water at room temperature. The green synthetic approach of CuO NPs, greener medium, easy workup and proficient recyclability are advantages in the said protocol. This is first time report of catalytic activity of biogenic CuO NPs in water at room temperature in the presence of NaPTS.

Association behavior of the amphiphilic drug and sodium p-toluenesulfonate mixtures: Effect of additives

The interaction between an amphiphilic phenothiazine drug—promethazine hydrochloride (PMT)—and anionic hydrotrope sodium p-toluenesulfonate (NaTS) mixtures was analyzed and the effect of different mole fractions (α1) of NaTS along with the variation of temperature was also investigated in three different media, water/NaCl (50 mmol.kg−1)/urea (U) (300 mmol.kg−1), using a conductometric method. Drug PMT is mainly utilized to cure allergic symptoms. From the study of pure components along with solution mixtures of components, various physicochemical parameters were evaluated and discussed thoroughly. The obtained results show that the experimental critical micelle concentrations (cmcs) are less than their corresponding ideal cmc (cmcid) values, showing the interaction amongst the constituents (PMT and NaTS). Mixing of dissimilar kinds of amphiphiles has an opportunity to bring about additional valuable acts owing to their attractive interaction. As hydrophobicity of the PMT + NaTS mixtures increased, therefore the cmc values remarkably decreased. The degree of dissociation (g) of the studied system was also evaluated and found to increase with a rise in temperature and decrease via an increase in α1 of NaTS. In salt (NaCl) solution, cmc and g-value of PMT and PMT+ NaTS at all compositions were decreased compared with an aqueous system while in U solution their value was found to be greater than in aqueous solution. Various theoretical models were also considered to estimate the fraction of hydrotrope in mixed micelles PMT + NaTS, the parameter is named the micellar mole fraction (X1Rb (Rubingh model), X1Rd (Rodenas model) and their ideal value is X1id), and the obtained value shows the higher composition of NaTS in mixed micelles along with their value increasing through an increase of α1 of NaTS in the solution mixture. One other parameter, called the interaction parameter (β), was observed as negative throughout the study, also proving the attractive interaction/synergism amongst the components of the solution mixture (PMT + NaTS). Assessed activity coefficients were all below one, showing the nonideality of the studied system. Several thermodynamic parameters of micellization, such as Gibbs free energy (ΔGm0), enthalpy (ΔHm0), and entropy (ΔSm0) have been determined in all studied media and compositions. UV–visible spectroscopy also confirmed the interaction amongst PMT and NaTS. Scanning electron microscope (SEM) images depicted a clear-cut interaction of PMT and NaTS interaction. The outcomes from the current study are significant in the expansion of the operative model drug delivery process.

Retraction

The development of a precipitation or crystallization step requires knowing the solubility of the target protein and its crystallization behavior in aqueous solutions at different pH, temperatures and in the presence of precipitating agents, especially salts. Within this work, a solubility model for proteins based on the second osmotic virial coefficient B22 is developed. For this, a relation between protein solubility and B22 was combined with the extended DLVO model. This solubility model was then used to model and also predict the protein solubility of lysozyme and monoclonal antibody for different salts, salt concentrations, and pH. The modeled as well predicted B22 and protein solubility data of lysozyme in the presence of sodium chloride and sodium p-toluenesulfonate and of a monoclonal antibody in the presence of ammonium sulfate at different pH shows good agreement with experimental data. This article is protected by copyright. All rights reserved.