P-toluene Sulfonate Research Articles

Au surface plasmon resonance promoted charge transfer in Z-scheme system enables exceptional photocatalytic hydrogen evolution

Highly efficient photocatalytic water reduction to evolve hydrogen can be achieved by the construction of Z-scheme systems that mimics natural photosynthesis. However, coupling appropriate semiconductors with suitable water reduction potential still remains challenging. Herein, we report a novel Z-scheme system, based on the Au decorated 5,10,15,20-tetrakis(4-trimethylammoniophenyl) porphyrin tetra(p-toluene sulfonate) functionalized iron-doped carbon nitride. We prepared carbon nitride by varying the amount of iron dopant and then functionalized with porphyrin to obtain heterostructure photocatalyst. Owing to the strong interfacial contact and proper band alignment, a Z-scheme system is fabricated. Finally, we deposited Au nanoparticles over the surface of the as-fabricated Z-scheme system to promote the surface redox properties via efficient charge carrier’s separation and transfer. The 3Au-3 P/30Fe-CN photocatalyst achieved excellent H2 evolution activity by producing 3172.20 µmol h−1 g−1 under UV–visible irradiation. The calculated quantum efficiencies for 3Au-3 P/30Fe-CN photocatalyst at 365 and 420 nm irradiation wavelengths are 7.2% and 3.26%, respectively. The experimentally observed efficiency of our photocatalyst is supported by the density functional theory simulations in terms of the lowest work function and strong electrostatic interaction among the constituents of Z-scheme system.

Separation of Polar Compounds using Poly(Ethylene Oxide) Bonded Stationary Capillary Liquid Chromatography

Poly(ethylene oxide) (PEO) bonded stationary phase has been synthesized by a single and simple step reaction. Poly(ethylene glycol monomethyl ether p-toluene sulfonate) (tosylated-PEO, molecular weight 900, n ≈ 18) was chemically bonded to 3-aminopropyl silica (TSKgel NH2-60, 5 µm particle size, and 60 Å mean pore diameter). The prepared stationary phase was able to separate polar compounds such as phenolics and nucleobases in capillary liquid chromatography. The retention and separation of phenolics and nucleobases could be achieved under isocratic elution condition. Nucleobases such as thymine, adenine, uracil, uridine, cytidine and toluene and phenolics (phenol, pyrocatechol, pyrogallol) were baseline separated in less than 6 min using 98% acetonitrile and less than 7 minutes using 80% acetonitrile, respectively. We demonstrated that the retention of nucleobases as analyte decreased with decreasing eluent concentration. The retention of these polar compounds was believed to be based on dipole-dipole and/or hydrogen-bonding interactions.

Study of the Distribution of Acetaminophen and Its Metabolites in Rats, from the Whole-Body to Isolated Organ Levels, by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging after On-Tissue Chemical Derivatization.

During drug development, detailed investigations of the pharmacokinetic profile of the drug are required to characterize its absorption, distribution, metabolism, and excretion properties. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is an established technique for studies of the distribution of drugs and their metabolites. It has advantages over autoradiography, which is conventionally used for distribution studies: it does not require the radiolabeling of drugs and can distinguish between the drug and its metabolites directly in the tissue. However, its lack of sensitivity in certain cases remains challenging. Novel procedures, such as on-tissue chemical derivatization (OTCD), could be developed to increase sensitivity. We used OTCD to enhance the sensitivity of MALDI-MSI for one of the most widely used drugs, acetaminophen, and to study its distribution in tissues. Without derivatization, this drug and some of its metabolites are undetectable by MALDI-MSI in the tissues of treated rats. We used 2-fluoro-1-methylpyridinium p-toluene sulfonate as a derivatization reagent, to increase the ionization yield of acetaminophen and some of its metabolites. The OTCD protocol made it possible to study the distribution of acetaminophen and its metabolites in whole-body sections at a spatial resolution of 400 μm and in complex anatomical structures, such as the testis and epididymis, at a spatial resolution <50 μm. The OTCD is also shown to be compatible with the quantification of acetaminophen by MALDI-MSI in whole-body tissues. This protocol could be applied to other molecules bearing phenol groups and presenting a low ionization efficiency.

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.

Integrable all-optical switch for photonic integrated circuits

A completely new model of an all-optical switch (AOS) is proposed using a silicon photonic crystal (PhC) slab based nonlinear Mach–Zehnder interferometer (NMZI). Both arms of the NMZI are designed using p-toluene sulfonate (PTS) based slotted PhC waveguides (PTS-SPCWs). Extreme optical confinement in SPCW is used here to intensify optical nonlinearities of PTS. The intensified nonlinearity produces significant phase changes in optical pulses within a small waveguide length, even when the optical power is sufficiently small. One arm of the NMZI is coupled with a control wave to incur additional phase shift compared to the other due to cross-phase modulation, in addition to self-phase modulation, which is a common phenomenon for both. The differential phase shift originates destructive/constructive interference, leading to a successful switching operation of the AOS. Switching characteristics of the AOS are evaluated for a variety of parameters. A typical example shows that the AOS can switch off 12.55 mW probe power with an extinction ratio of ≈ 50.5 d B by applying 5.65 mW control power, while the device footprint is merely 259 µ m 2 . The low-power and high-speed operation makes this small footprint AOS device suitable for applications in photonic integrated circuits.

Protic/aprotic ionic liquids for effective CO2 separation using supported ionic liquid membrane

Four ionic liquids (ILs) namely, 1-butylsulfonate-3-methylimidazolium P-toluene sulfonate ([BSmim][tos]), 1-butylsulfonate pyridine P-toluene sulfonate ([BSmpy][tos]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and 1-butylpyridine chloride ([Bpy][Cl]) were synthesized for the effective separation of gases CO2/N2 and CO2/CH4 through supported ionic liquid membranes (SILMs). ILs were confirmed by NMR and FTIR spectroscopy, and their characteristics and physical properties were studied. The ILs were immobilized on the porous hydrophobic 200 μm thick polyvinylidene difluoride (PVDF) support. Pure and mixed gas separation performances of the prepared SILMs were analyzed in a custom-built gas permeation unit. The SILMs were stable up to 0.6 MPa at room temperature without leaching the ionic liquid. [BSmim][tos] was recorded to have the highest solubility coefficient and permeability for CO2, among other ILs. At 0.5 MPa, for pure CO2/N2 and CO2/CH4, IL [BSmim][tos] was observed with selectivities of 56.2 and 47.5, respectively. Based on the SILMs separation performance, the ILs synthesized for this work can be ranked as [BSmim][tos] > [BSmpy][tos] > [Bmim][Cl] > [Bpy][Cl]. Moreover, the exceptionally high selectivity values of [BSmim][tos] and [BSmpy][tos] confirms the potential use of ILs for CO2 separation through SILMs.

Fitting of experimental viscosity to temperature data for deep eutectic solvents

Seven new deep eutectic solvents (DESs) based on tetrabutylammonium bromide (TBAB) and tetraethylammonium p-toluene sulfonate (TEAPTS) were prepared and their viscosity determined between 298.15 and 323.15 K. The effect of temperature was modeled using an appropriate fitting procedure, proposed in this work, with a coefficient of determination R2 > 0.99 for all DES. The fitting procedure used of pre-existing experimental data in which 70 DESs were collected from the literature and refined on the basis of R2 and root mean square error (RMSE); ~10% of the data was rejected. Furthermore, about half of the refined data was fitted with a three-parameter Vogel–Fulcher–Tammann (VFT) equation with an R2 higher than 0.99. The remaining data were more adequately fitted with a two-parameter Arrhenius equation. The adjusted parameters of both models for 62 DESs were determined to estimate the viscosity. Based on R2, the VFT model was more accurate than the Arrhenius model. Moreover, additional in-lab experiments were performed for model validation at six temperatures (from 298.15 to 323.15 K). In some cases, the experimental measurements were different from those in the literature with an R2 below 0.95 indicating a large scatter in the viscosity data. Most of the highly viscous DESs considered in this study showed a rapid decay when temperature increases. Hence, the limitation of using these solvents for applications such as absorption could be overcome by operating at slightly higher temperature (i.e., 313.15 to 333.15 K).

An elaborate investigation on the transition of rod-like micelle of cetyltrimethylammonium p-toluenesulfonate in presence of different additives

Abstract The noticeable change in self-aggregation nature (rod-like micelle) of cetyl trimethylammonium p-toluene sulfonate (CTAT) in presence of various electrolytes and non-electrolytes was probed using tensiometry, conductometry, isothermal titration calorimetry and fluorimetry. The impact of electrolytes and non-electrolytes on the critical micelle concentration (CMC) of the surfactant was found to be opposite of each other. The non-electrolytes having lower dielectric constants than water increased the repulsion between the surfactant head groups, thereby increasing the CMC. Less negative value of ΔG0m with increase in solvent concentration indicated delayed process of micellization. On the contrary, electrolytes decreased the CMC by a large extent due to suppression of the repulsion between the charged head groups by supplying more counter ions from the salts. The aggregation number of CTAT solution in presence of electrolytes increased with increase in salt concentration but decreased in presence of non-electrolytes, with increase of its concentration. The packing parameter value indicated the transition towards spherical shape with increase in concentration of non-electrolytes and increase in more non-spherical shape with increase in concentration of electrolytes for rod-like micelles of CTAT.

Optimization of soybean oil transesterification using an ionic liquid and methanol for biodiesel synthesis

Fatty acid methyl esters (FAME) were synthesized through the transesterification of soybean oil with methanol using an ionic liquid as a catalyst. The ionic liquid 3-(N, N-dimethyldocecyl ammonium) propane sulfonic acid p-toluene sulfonate ([DDPA] [Tos]) was synthesized, characterized and used for the transesterification of soybean oil for biodiesel synthesis. Factors affecting the reaction, including the soybean-oil-to-methanol ratio (1:2 v/v), the ionic liquid catalyst concentration of 8.0 %w/v, the reaction time of 4 h, the agitation speed of 300 rpm, and the constant refluxing reaction temperature were optimized. A 75 % yield of biodiesel was obtained under the optimized conditions. The biodiesel was purified using an ion exchange resin and then the analyzed by GC–MS. The properties of the biodiesel such as kinematic viscosity at 40 ºC, the density at 25 ºC, the cloud point and pour points were also determined. The biodiesel met the quality standard defined under ASTM D6751-02. In this research study, a novel method for biodiesel synthesis under mild conditions using methanol and an ionic liquid was developed.

Lignin Conversion Using Catalytic Ionic Liquids: Understanding the Role of Cations, Anions, and Hammett Acidity Functions

Because it is undisputable that lignin depolymerization is a must to make the biorefinery concept economically feasible, several efforts are put toward it; however, a lot of catalyst designing is required to achieve efficient depolymerization activities. In this work, we show a systematic approach in the synthesis and characterization of ionic liquids (ILs) with varying combinations of cations (imidazole, benzimidazole, phosphonium, and ammonium) and anions (HSO4, PTS (p-toluenesulfonate), Cl, H2PO4, SnCl3, FeCl4, and CuCl3) for the depolymerization of lignin into low-molecular weight aromatic fractions (<220 g/mol) under mild reaction conditions (120 °C, 1 h, ambient pressure). In a methodical approach, effects of various reaction parameters such as temperature (70–170 °C), time (15–360 min), pressure (N2, 0.5–3 MPa), solvents and substrate, and so forth were studied to achieve best activity. Among all the catalysts, IL with the imidazolium cation and HSO4 as the anion showed best activity (78% yield). Subsequent to depolymerization, three aromatic monomers (5 wt % pure vanillin) were isolated using flash column chromatography. These aromatic monomers were characterized using gas chromatography (GC), GC–mass spectrometry, and NMR techniques for their purity. Hammett acidity functions (H0) of ILs were measured using UV–vis photo-spectroscopy, and values are correlated with lignin depolymerization results. Lignin and tetrahydrofuran-soluble products were thoroughly characterized using assorted physicochemical techniques such as NMR (1H and 13C), gel permittivity chromatography, thermogravimetric analysis, and so forth. The catalyst was recycled up to six runs and showed similar results in consecutive reactions.

Catalytic synthesis of n-butyl carboxylate with immobilized ionic liquid based on response surface methodology optimization.

Four kinds of functional ionic liquids (ILs) ([C3SO3Hnmp]HSO4), 1-(3-sulfopropyl)-1-methylpyrrolidone phosphate ([C3SO3Hnmp]H2PO4), 1-(3-sulfopropyl)-1-methylpyrrolidone p-toluene sulfonate ([C3SO3Hnmp]CH3SO3H) and 1-(3-sulfopropyl)-1-methylpyrrolidone methyl sulfonate ([C3SO3Hnmp]C6H6SO3H)) were prepared and the catalytic activity of these ILs during esterification of carboxylic acids (formic acid, acetic acid, propionic acid, butyric acid) with alcohols was investigated. The results indicated that the IL ([C3SO3Hnmp]HSO4) exhibited an optimal catalytic performance. And then the IL ([C3SO3Hnmp]HSO4) was immobilized to the silica gel. The immobilized IL performed more excellent catalytic activity than the unsupported [C3SO3Hnmp]HSO4. The effects of reaction temperature, reaction time, molar ratio of acid to alcohol and catalyst dosage were investigated. The response surface methodology based on the Box–Behnken design (BBD) was used to explore the best reaction condition of different experimental variables. Accordingly, a high n-butyl butyrate yield of 97.10% under the deduced optimal reaction conditions was obtained, in good agreement with experimental results and that predicted by the BBD model. The immobilized IL [C3SO3Hnmp]HSO4 maintained high catalytic activity after five cycles.

Ionic liquid crystals derived from dl-Phenylalanine: Mesomorphism, optical behavior and evaluation of toxicological profile

Methane sulfonate and p-toluene sulfonate (4-methyl benzene sulfonate) salts of esters of racemic 2-Amino-3-phenylpropanoic acid (dl-Phenylalanine) and fatty alcohols were synthesized in good yields and investigated for their liquid crystalline properties using Polarizing Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC). Six out of seven derivatives were found to be liquid crystalline from the first series while four out of twelve derivatives were found to be ionic liquid crystals from the second series. The refractive indices of one of the ionic liquid crystals were measured at variable wavelengths and temperatures and found to exhibit a high Abbe number and low dispersive power. For evaluation of the toxicological profile, binding interactions of hsDNA with one of the derivatives from each series were recorded under physiological conditions. The experimental studies by UV–Visible and Fluorescence spectroscopy suggested a weak interaction between the ionic liquid crystals and hsDNA and, that too, mainly through minor grooves. As the strength of binding seems to be weak, a safe nature of the reported ionic liquid crystals could be expected.

Studies on the third order nonlinear optical properties of a novel o-Phenylenediaminium p-Toluenesulfonate single crystal

Organic nonlinear optical o-Phenylenediaminium p-Toluene sulfonate single crystal was grown by slow evaporation solution growth method. The crystal system and lattice parameters were confirmed by single crystal X-ray diffraction studies. Thermal stability (246 °C) of the system was observed by thermal studies. UV-Vis spectral studies revealed the lower cut-off wavelength transparency and corresponding band gap. Photoluminescence emission peak of the crystal occurred in yellow region. Third order nonlinear optical properties were elucidated by Z-scan technique and found that the crystal possesses saturable absorption and the self-defocusing effect.

Aqueous hydrotropic solution: green reaction medium for synthesis of pyridopyrimidine carbonitrile and spiro-oxindole dihydroquinazolinone derivatives

From the green chemistry point of view, water is one of the most sustainable solvents for chemical transformations, but there are some limitations to its use as a reaction medium due to the lack of solubility of organic compounds. To overcome this difficulty, we used aqueous hydrotropic solution, which increases the solubility of organic compounds in water by 200-fold. We report an environmentally efficient method for synthesis of pyridopyrimidine carbonitriles and spiro-oxindole dihydroquinazolinones by using 50 % aqueous sodium p-toluene sulfonate (NaPTS) solution at ambient reaction condition. The merits of the present protocol include short reaction time, excellent product yield with high purity, easy workup procedure and reusability of reaction medium.

Electrochemically controlled transport of anions across polypyrrole-based membranes

Electrosynthesized polypyrrole (PPy) films on PVDF/Pt support membranes were used to study electrochemically controlled transport of monovalent and divalent anions across the PPy-based membranes. The PVDF/Pt/PPy membrane separated two compartments in a transport cell and served simultaneously as the working electrode allowing electrochemical switching of PPy between its oxidized and reduced forms during the transport experiments. PPy was electrosynthesized in presence of p-toluene sulfonate, camphorsulfonate and hexafluorofosfate (doping ions) and the ion transport properties of the resulting PPy-based membranes were investigated. The morphology and elemental composition of PPy before and after the anion transport studies were studied by SEM and EDXA. The anion fluxes obtained during transport of a mixture of Cl−, NO3−, SO42− and HAsO42− across the PPy-based membranes were found to decrease in the following order: NO3− > Cl− » SO42− > HAsO42−. PPy films with the same composition as for the transport studies were also electrodeposited on glassy carbon electrodes (GC/PPy) and studied by potentiometry. The potentiometric selectivity of the GC/PPy electrodes towards Cl−, NO3− and SO42− was found to correlate with the ion transport characteristics of the corresponding PPy membranes used in the transport cell. The PPy-based membranes allowed separation of monovalent from divalent anions.

Photodynamic inactivation of non-enveloped RNA viruses

We recently reported the photodynamic inactivation (PDI) of bacteriophage MS2 with a photosensitiser- 5, 10, 15, 20-tetrakis (1-methyl-4-pyridinio) porphyrin- tetra- p-toluene sulfonate (TMPyP) in solution and concluded that the A-protein of the virus is the main target of inactivation. Here, we have extended these studies and carried out PDI of bacteriophage Qβ, bovine enterovirus 2 (BEV-2) and type 1 murine norovirus (MNV-1). The rate of inactivation observed was in the order MS2 > Qβ > MNV-1 > BEV-2. Data suggested that TMPyP-treatment could also target the viral genome as well as result in disintegration/disassembly of viral particles. Although emergence of viral drug resistance is a well-documented phenomenon, it was not possible to generate PDI-resistant MS2. However, emergence of a mutation in the lysis protein was detected after serial exposure to PDI.

Novel 3-Methyl-2-alkylthio Benzothiazolyl-Based Ionic Liquids: Synthesis, Characterization, and Antibiotic Activity

Three series of novel 3-methyl-2-alkylthio benzothiazolyl ionic liquids (ILs) were synthesized for the first time. After structural identification, their melting point, solubility, and thermostability together with antibiotic activity were determined successively. As a result, 3-methyl-2-alkylthio benzothiazolyl p-toluene sulfonate was found to have the highest antibacterial activity among the three series of ILs. Meanwhile, it has a good solubility in water as well. On the basis of comprehensive comparison with similar compounds, the effect of cations and anions of these benzothiazolium ILs on typical physical properties together with antibiotic performance was explored and discussed, which is very beneficial to take the greatest advantage of their structural designability for various purposes. Furthermore, the experiment data preliminarily discovered the relationships of the structure-properties/activities of the above three kinds ILs to a certain extent, which can provide useful references for future research and for the potential application of these new ILs as surfactant antiseptics or agricultural chemicals.

Slow Light Propagation in Photonic Crystal-Based Meandering Delay Lines Using the PTS Material

In this paper, rectangular and triangular photonic crystal (PC) delay lines are designed using PTS (p-toluene sulfonate) at 1550 nm. PTS possesses a high nonlinear refractive index; consequently, when it interacts with an incident light, it provides slow light propagation in a PTS-based device due to the Kerr effect. First, a PC waveguide (PCW) is designed by introducing a line defect made of PTS bars. Such a defect, by using PTS, provides two significant advantages; these include slow group velocity and extremely high optical confinement for a propagating wave through the PCW. Then, two similar PCWs are placed next to each other to investigate the crosstalk phenomenon between them. By choosing an appropriate distance between them, the rectangular and triangular PC reflective meandering delay lines are realized. The rectangular lattice PC reflective meandering delay line exhibits lower propagation losses because this lattice shows a higher transmission coefficient at the corners in comparison with the triangular one. On the other hand, the triangular lattice PC reflective meandering delay line provides very low group velocity for a propagating light wave at the wavelength of 1550 nm; as a consequence, a higher slowing factor is achieved for the triangular lattice PC reflective meandering delay line due to the stronger light–PTS interactions. Simulations are performed using LUMERICAL FDTD SOLUTION v8.15.

Reply to “Comment on ‘Determination and Correlation of Dipyridamole p-Toluene Sulfonate Solubility in Seven Alcohol Solvents and Three Binary Solvents’”

The Comment on “Determination and Correlation of Dipyridamole p-Toluene Sulfonate Solubility in Seven Alcohol Solvents and Three Binary Solvents” is appreciated. According to the comments, we make a deep analysis and discussion of our article again. The reason for large deviations between the back-calculated value presented in our paper and the back-calculated value calculated by Acree is that we mixed up the coefficients calculated by two programs and the wrong Apelblat equation coefficients were submitted in our paper instead of the corrected ones. Therefore, the model parameters of the Apelblat equation and the calculated mole fraction solubilities of dipyridamole p-toluene sulfonate in all solvents at the temperature ranging from 288.15 to 328.15 K were recalculated by the corrected program and show satisfactory correlation results with the experimental values.

The Initial Comparison Study of Sodium Lignosulfonate, Sodium Dodecyl Benzene Sulfonate, and Sodium p-Toluene Sulfonate Surfactant for Enhanced Oil Recovery

Surfactant (surface active agent) exhibit numerous interesting properties that enable their use as additional component in mobilising of residual oil from capillary pore after secondary recovery process using gas injection and water flooding. In this study, Sodium Lignosulfonate (SLS) surfactant was successfully synthesized by applying batch method using lignin from oil palm empty fruit bunches as precursor. Furthermore, its performance in reducing interfacial tension of crude oil and formation water colloidal system was compared with commercial available surfactant including Sodium Dodecyl Benzene Sulfonate (SDBS) and Sodium p-Toluene Sulfonate (SpTS). The synthesized SLS surfactant was characterized by using Fourier Transform Infrared (FTIR) spectroscopy. Meanwhile, its performance in reducing interfacial tension of crude oil and formation water colloidal system was analyzed by using compatibility test, phase behaviour analysis, and interfacial tension (IFT) measurement. The compatibility test shows that SLS, SDBS, and SpTS surfactants were compatible with formation water. In addition, the phase behaviour analysis shows that SLS surfactant was better than SpTS surfactant, while SDBS surfactant generates the highest performance proved by the best microemulsion formation resulted by SDBS. Furthermore, the optimum concentration of SLS, SDBS, and SpTS surfactants in reducing the interfacial tension of crude oil and formation water was 1.0%. The IFT measurement indicates that the performance of SLS with the value of 1.67 mN/m was also better than SpTS surfactant with the value of 3.59 mN/m. Meanwhile, SDBS surfactant shows the best performance with the IFT value of 0.47 mN/m.