4-sulfophthalic Acid Research Articles

Antimicrobial potential and protein binding affinity of a hybrid ternary nanocomposite matrix: Zinc oxide functionalization with poly(vinyl alcohol)-sulphonated graphene oxide-poly pyrrole

The present study focuses on the application of a ternary PVA/sGO/ZnO-NP/PP nanocomposite as an antibacterial and antifungal agent. The process involved utilizing a solution casting technique to fabricate the inorganic–organic blend material, where 4-sulfophthalic acid (SPTA) was used in the sulfonation of graphitic oxide (GO) sheets. The amalgamation of polyvinyl alcohol polymer (PVA) and sulphonated GO (sGO) was achieved through a chemical oxidation polymerization process carried out in a water-based environment. This process developed a PVA/sGO film, in which zinc oxide nanoparticles (ZnO-NP) and pyrrole monomers were introduced. The PVA/sGO film served as the initial stage for the in-situ deposition and formation of polypyrrole (PP), leading to the fabrication of PVA/sGO/ZnO-NP/PP membrane. The structure was stabilized by hydrogen bonding and electrostatic interactions between the components, while SPTA acted as a cross-linker and a sulphonating agent. The Fourier transform infrared (FTIR) spectra of the quad-component composite unraveled the presence of distinctive functional groups, including PVA, sGO, PP, and Zn-O bands. The UV–visible spectra of PVA/sGO/ZnO-NP/PP nanocomposite membrane revealed a peak in the UV-B region, while in-depth X-ray diffraction (XRD) analyses provided strong evidence of its amorphous nature. The scanning electron microscopy (SEM) image showed that the top surface of the organic film was adorned with PP polymeric chains. The membrane exhibited great water retention capabilities due to its high ion exchange capacity (IEC) value.Additionally, the minimal water loss observed underscores its extended shelf life. Due to their inherent hydrophilic properties, the ternary nanocomposite membranes exhibited enhanced hydrophilicity, porosity, zeta potential, and water uptake. The BET and BJH analyses revealed that PVA/sGO/ZnO-NP/PP nanocomposites had a substantial surface area. Remarkably, the nanocomposite membrane exhibited significantly improved antimicrobial efficacy against bacteria and fungi. The type of interactions between Human serum lysozyme (HSL) and nanocomposite at the molecular level was studied through fluorescence spectroscopy. Stern-Volmer plot revealed the occurrence of both static and dynamic quenching. However, the precise mechanisms underlying the antimicrobial and protein binding (HSL) studies of PVA/sGO/ZnO-NP/PP-based nanocomposites require further investigation.

Water-soluble ozonated lignin as a hydrophilic modifier for poly(vinyl alcohol) membranes for pervaporation desalination

Poly (vinyl alcohol) (PVA)-based membranes are widely applied to pervaporation desalination. Further modification of the PVA-based membranes with suitable additives is attractive for increasing the water permeation fluxes. In this work, water-soluble ozonated lignin (Ws-OL) was prepared and used as an additive for preparation of Ws-OL-modified PVA membranes, which showed relatively high surface hydrophilicity, reduced crystallinity, and small crystallite sizes compared to the neat PVA membrane. The Ws-OL modification brought a 2.1 times of water permeation flux to the PVA membrane in pervaporation desalination on a 3.5 wt% NaCl(aq) solution at 25 °C. Under an optimum condition, the modified PVA membrane possessing 50 wt% Ws-OL and being crosslinked with 4-sulfophthalic acid (SPTA) exhibited a water permeation flux and a salt rejection of 78,630 g m-2 h-1 and 99.91%, respectively. The high efficiency of Ws-OL in modifying hydrophilic membranes is noteworthy and could be potentially applied to other membranes for pervaporation separation and oil-water separations.

Porous PVA-g-SPA/PVA-SA Catalytic Composite Membrane via Lyophilization for Esterification Enhancement.

A catalytic composite membrane was developed for the enhancement of esterification by lyophilization for the first time. The catalytic composite membrane was composed of a poly(vinyl alcohol) (PVA)-sodium alginate (SA) separation layer and a spongy porous catalytic layer cross-linked by PVA and 4-sulfophthalic acid (SPA). Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) results indicated the successful synthesis of the catalytic composite membrane. The membrane properties were evaluated by ethanol dehydration and esterification. The conversion rate of acetic acid reached 95.9% after 12 h. Compared with batch reactions, the conversion rate increased by 24.4%. After five cycles, the membrane still maintained outstanding catalytic activity. The resistance of mass transfer was analyzed, and the results showed that the porous structure reduced the catalytic layer resistance to total resistance from 70.27 to 32.88%. The composite membrane with a spongy porous catalytic layer exhibited superior dehydration and catalytic performance.

Influences of crosslinked carboxylic acid monomers on the proton conduction characteristics of chitosan/SPVA composite membranes

This work aims to study the effect of using sulfosuccinic acid (SSA) and 4-sulfophthalic acid (SPTA) to crosslink the chitosan/poly(vinyl)alcohol (CS/PVA) composite membrane on the proton conduction properties for fuel cell applications. The CS/SPVA membranes were prepared with different CS to PVA ratios with a fixed mass of crosslinker. The results indicated that SSA, with the presence of –SO3 groups, is more effective in crosslinking the composite membrane. The ionic conductivity SSA crosslinked membrane is of one order higher than that with SPTA. Composite membrane with CS:SPVA ratio of 15:85 crosslinked with SSA has the highest ionic conductivity of 6.58 mS/cm and a IEC value of 1.4556 mequiv/g, respectively. In addition, it exhibits stable ionic conductivity over the temperature range of 25–80 °C with minimal weight loss below 100 °C, indicating its potential application as proton exchange membrane for fuel cell applications. Calculated activation energy Ea of 12.696 kJ/mol in comparison to Nafion membrane (9.34 kJ/mol), suggesting the proton transport through Grotthuss mechanisms.

Synthesis and Characterization of Novel Green Hybrid Nanocomposites for Application as Proton Exchange Membranes in Direct Borohydride Fuel Cells

Organic–inorganic nanocomposite membranes for potential application in direct borohydride fuel cells (DBFCs) are formulated from sulfonated poly(vinyl alcohol) (SPVA) with the incorporation of (PO4-TiO2) and (SO4-TiO2) nanotubes as doping agents. The functionalization of PVA to SPVA was done by using a 4-sulfophthalic acid as an ionic crosslinker and sulfonating agent. Morphological and structural characterization by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) confirmed the successful synthesis of the doping agents and their incorporation into the polymer. The influence of PO4-TiO2 and SO4-TiO2 doping and their content on the physicochemical properties of the nanocomposite membranes was evaluated. Swelling degree and water uptake gradually reduced to 7% and 13%, respectively, with increasing doping agent concentration. Ion exchange capacity and ionic conductivity of the membrane with 3 wt.% doping agents were raised 5 and 7 times, respectively, compared to the undoped one. The thermal and oxidative stability and tensile strength also increased with the doping content. Furthermore, lower borohydride permeability (0.32 × 10−6 cm2 s−1) was measured for the membranes with higher amount of inorganic doping agents when compared to the undoped membrane (0.71 × 10−5 cm2 s−1) and Nafion®117 (0.40 × 10−6 cm2 s−1). These results pave the way for a green, simple and low-cost approach for the development of composite membranes for practical DBFCs.

Elucidating the impact of polymer crosslinking and fixed carrier on enhanced water transport during desalination using pervaporation membranes

Crosslinking is a well-established technique to enhance chemical stability of polymer membranes but at the expense of lower flux. We previously demonstrated that this trade-off between chemical stability and separation performance can be overcome through the judicious selection of a crosslinking agent, 4-sulfophthalic acid (SPTA), which also functioned as a fixed carrier site. The mechanism underpinning this breakthrough remained unknown. Through molecular dynamic simulations and a series of complementary experiments, here we reveal that higher crosslinking degree can increase local water concentration close to the sulfonic acid groups, and enhance both long-distance water-sulfonic acid-interactions and water molecule mobility. These underpinned the significant increase in water flux of crosslinked pervaporation membranes during desalination. These results show that the dependence of water diffusivity on water concentration is reduced with higher crosslinking degree. More importantly, water diffusivity at the “dry membrane region” determined the overall water transport behaviour. These findings can potentially impact on the design of pervaporation membranes for production of potable water from brackish, sea and brine water.

Water permeance, permeability and desalination properties of the sulfonic acid functionalized composite pervaporation membranes

In spite of the great promise of pervaporation (PV) in production of fresh water from salty water, major challenge still lies in the developments of PV membranes with high water flux to compete reverse osmosis membranes. Here, we fabricated composite PV membranes consisting of a porous polyacrylonitrile (PAN) substrate and a dense selective layer of polyvinyl alcohol (PVA) crosslinked by 4-sulfophthalic acid (SPTA) of which sulfonic acid groups acted as facilitate transport agents to water molecules. Effects of the SPTA concentration and thickness of the PVA layer to the desalination performance were studied at temperatures from 30 to 70 °C and NaCl concentrations up to 100,000 ppm. A high water flux of 46.3 kg/(m2·h) with a salt rejection of 99.8% was achieved when separating a 35,000 ppm NaCl solutions at 70 °C. However, water permeance only increased 5.3 times as the PVA layer thickness decreased 95 times (from 76 μm to 800 nm). Our study showed that water permeability of the PVA layer significantly decreased with thickness of the PVA layer. This phenomenon indicated that a thin and dried region close to the downstream side of the PVA layer governed the water transport property.

Mechanism of oxidation of 3-hydroxy-2,7-naphthalenedisulfonic acid disodium salt with oxygen in subcritical water

The article presents the results of studies on the oxidation mechanism of 3-hydroxy-2,7-naphthalenedisulfonic acid disodium salt (R-salt) with oxygen in subcritical water. To this aim, a series of experiments were carried out which showed that at a temperature of 413 K and pH > 9 the oxidation reaction of a substrate with oxygen was relatively quick and after approximately 40 min the R-salt oxidation yield exceeded 95%. In an acidic medium (pH < 7), the rate of R-salt oxidation is small.In order to identify the mechanism of R-salt oxidation, experiments were carried out at 413–569 K in solutions with pH = 10.0 and at partial oxygen pressure pO2 = 1.73 MPa. As a result of these experiments, a stable oxidation product was isolated from the reaction mixture and subjected to spectroscopic analysis. The analysis of HNMR of this product proved that a stable intermediate product of R-salt oxidation was 4-sulfophthalic acid sodium salt.The results of the experiments have shown that destructive oxidation of R-salt can easily be obtained at a temperature of 413 K, but satisfactory reduction of TOC in wastewater containing this substrate requires the use of very high temperature: at 569 K only 60% reduction of TOC was achieved.

Efficient synthesis of bis(indolyl)methanes, bispyrazoles and biscoumarins using 4-sulfophthalic acid

4-Sulfophthalic acid (4-H3SPA) solution 50 wt% in H2O has been effectively catalyzed the synthesis of a series of biologically relevant bis(indolyl)methanes by the electrophilic substitution of indole derivatives on aldehyde compounds and 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s by condensing 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with various aldehydes under aqua conditions at room temperature. 3,3′-(Arylmethylene)-bis-4-hydroxycoumarins have also been synthesized in the presence of 0.1 mL (0.262 mmol) of 4-H3SPA solution 50 wt% in H2O at 80 °C. The procedure is simple and the expected bis-heterocyclic compounds were isolated in good to excellent yields. The present protocol provides the benefits of convenience, mild reaction conditions, eco-friendliness, and no use of hazardous organic solvents.

An approach of balancing the ionic conductivity and mechanical properties of PVA based nanocomposite membrane for DMFC by various crosslinking agents with ionic liquid

Nano composite membranes of polyvinyl alcohol (PVA) have been synthesized to investigate their applicability as a proton conducting membrane for direct methanol fuel cell. These membranes consist of PVA, sulfonated organic modified montmorillonite nanoclay (SMMt) and 1-butyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide (BMIM TFSI) with different crosslinking agents such as sulfosuccinic acid (SSA), 4-sulfophthalic acid (SPA) and dodecanedioic acid (DDA). FTIR spectroscopy, scanning electron microscope (SEM) and thermogravimetric analysis (TGA) have been used to investigate the structure property relationship. The water uptake behavior of the membranes shows variation with the dosage of SMMt. The good dispersion of the nanoclay in the PVA matrix is detected by using ionic liquid. The improved tensile strength of the membrane comprising 3 wt% of SMMt is achieved. The proton conductivities of the membranes are dependant on the compositions and are in the range of 0.003–0.008 Scm−1 at room temperature and 100% relative humidity. A maximum proton conductivity of 0.017 Scm−1 has been obtained for the membrane comprising of 3 wt% SMMt at 80 °C. Furthermore, the peak power density of the direct methanol fuel cell fabricated with 3 wt% SMMt based membrane in 2 M methanol is 7.02 mW cm−2 at 70 °C.

Polymer electrolyte membranes based on sulfonated polysulfone and functionalized layered silicate for direct methanol fuel cell applications

Polymer electrolyte membranes (PEMs) of sulfonated polysulfone (SPSf) and sulfonated montmorillonite (SMMT) have been developed. Sodium montmorillonite (NaMMT) has been sulfonated with 4-sulfophthalic acid and incorporated into the SPSf matrix for further enhancement of proton conductivity. Sulfonation of NaMMT has been confirmed using Fourier transform infrared spectroscopy and X-ray diffraction (XRD) analysis. The XRD patterns proved that the SMMT layers were completely exfoliated within the SPSf matrix. The performances of the PEM in terms of their liquid uptake, oxidative stability, and proton conductivity were investigated. The morphological characterizations have been carried out using scanning electron microscopy and atomic force microscopy. SPSf/SMMT membrane with 5 wt% of SMMT loading showed adequate thermal stability and an improved proton conductivity. The reduction in methanol permeability from 8.9 ×10−5 cm2 s−1 to 2.4 × 10−5 cm2 s−1 has been observed when SMMT loading content increased from 1 wt% to 5 wt%. Direct methanol fuel cell (DMFC) performance showed a power density value of 49 mW cm−2for SPSf/SMMT membrane, indicating its candidature for DMFC applications.

Non-stoichiometric complexes of cationic starch and 4-sulfophthalic acid and their flocculation efficiency

Non-stoichiometric complexes with an excess of free charges (NIC) were obtained during electrostatic interaction between quaternary ammonium groups of N-(2-hydroxyl)-propyl-3-trimethyl ammonium starch chloride (CS) and multifunctional 4-sulfophthalic acid (SPH). The formation of NIC was confirmed by equilibrium adsorption, FT-IR and luminescence spectroscopy experiments. The Langmuir, Freundlich, Dubinin–Radushkevich and Temkin adsorption models have been used to describe the equilibrium adsorption isotherms. The ratio between the negative and positive charges (n−/n+) calculated from the values of the Langmuir sorption capacity QL showed that the anionic charges were predominant in the complexes after equilibrium adsorption. NIC with an excess of positive charges were obtained during complex formation between the cationic groups of CS and the anionic groups of SPH. The NIC formed between CS and 25mol% (according to the cationic groups of CS) of SPH trianions showed the higher flocculation efficiency in destabilization of kaolin suspension in comparison with that of CS only.

Exploratory syntheses, structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse PbII coordination complexes, [Pb3O(OH)(4-sphth)]2(H2O) (1), [Pb(3,5-Hdhb)]H2O (2), and [Pb3(4-nphth)2(OH)2] (3) (4-H3sphth, 4-sulfophthalic acid; 3,5-H2dhb, 3,5-dihydroxybenzoic acid; 4-H2nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb4O4] cubanes, based on which ladder-shaped structure is built via 4-H3sphth bridge. This is the first Pb4O4-containing polymer. The Pb2O2 units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb3O units, which are linked through Pb corners to form a hexagonal unit. Each PbO6 polyhedron is connected to three polyhedra (Pb3O) via sharing an edge (two μ 3-oxygen atoms) and two faces (three μ 3-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.

First Water-Soluble μ-Nitrido Dimer of Iron Phthalocyanine

The μ-nitrido dimer of Fe-phthalocyanine μ-N(FePc)2 was first reported and actively studied in the middle of the 1980s.[1,2] Recently it was established that its tert-butyl substituted derivative μ-N(FePcBu4)2 catalyses the oxidation of methane by H2O2 under very mild conditions (25-60 oC),[3] and then a high catalytic activity was also demonstrated in the oxidation of other organic substrates.[4] It has been shown in theoretical work[5] that the ability of the μ-nitrido moiety to serve as a remarkable charge reservoir and to stabilise the lower spin-states can enhance the catalytic activity of μ-nitrido dimers of Fe-porphyrazines in comparison with the corresponding μ-oxo species. The water-soluble FeIIItetrasulfophthalocyanine in its μ-oxo form, μ-O(FeTSPc)2, catalyses various redox-reactions in aqueous medium.[6] Among μ-nitrido dimers so far only μ-N(FePcBu4)2 and other species well-soluble in organic solvents due to presence of alkyl residues were studied, including alkoxy[7] and alkylsulfonyl[8] substituted derivatives. We report here the synthesis of the first water-soluble derivative – the μ-nitrido dimer of Fe-tetrasulfophthalocyanine, μ-N(FeTSPc)2, which was prepared by two alternative routes (Scheme 1). In the first approach Fe-tetrasulfophthalocyanine, which was prepared by cyclotetramerization of 4-sulfophthalic acid,[9] was used as a starting material. In neutral or basic water solutions this species exists as μ-oxodimer μ-O(FeTSPc)2, [6]

Separation of isomers of sulfophthalic acid by guest induced host framework formation with 4,4′-bipyridine

The selective inclusion of aromatic guest molecules in host frameworks formed by 3-sulfophthalic acid or 4-sulfophthalic acid and 4,4'-bipyridine has been effectively utilized for the separation of sulfophthalic acid isomers.

Didecyl ester of 4-sulfophthalic acid as a plast dopant and emulsifier in the chemical polymerization of aniline into polyaniline salt

Polyaniline salt was synthesized through the chemical oxidation of aniline with sodium persulfate as the oxidant and didecyl ester of 4-sulfophthalic acid via three different polymerization pathways (aqueous, emulsion, and interfacial). In these polymerization processes, the ester acted as a novel plast dopant and as an emulsifier. The yield, conductivity, and number of ester units present in the polyaniline salts were determined. A polyaniline salt prepared by emulsion polymerization was soluble in chloroform and showed excellent solution-processing properties. Polyaniline samples prepared by aqueous or interfacial polymerization were not soluble in chloroform. A soluble polyaniline salt was successfully synthesized through the washing of an organic layer containing the polyaniline salt with water in emulsion polymerization. X-ray diffraction spectra of polyaniline salts prepared by the three different methods showed an ordered, layer-type supramolecular structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis, crystal structures, and characterization of three coordination compounds constructed from 4-sulfophthalic acid ligand

Three new coordination compounds with 4-sulfophthalic acid (H 3SPA) ligand, namely {[Pb 3(4-SPA) 2(H 2O)](H 2O)} n ( 1), [Mn(4,4′-bpy) 2(H 2O) 4][Mn 2(4-SPA) 2-(4,4′-bpy) 4(H 2O) 4]·7.5(H 2O) ( 2) and Cu 2(4-HSPA) 2(2,2′-bpy) 2(H 2O) 2 ( 3) (4,4′-bpy = 4,4′-bipyridine and 2,2′-bpy = 2,2′-bipyridine), have been synthesized. The structures exhibit different dimensionality depending on the nature of the metal ions and/or the ancillary ligands. Compound 1 has a 2D layered architecture constructed from one-dimensional inorganic lead(II) oxygen chains containing tetranuclear [Pb 4(μ 2-O) 4] cluster. Compound 2 has a dinuclear manganese [Mn 2(4-SPA) 2(4,4′-bpy) 4(H 2O) 4] motif charged with mononuclear [Mn(4,4′-bpy) 2(H 2O) 4] 2+ cation. Compound 3 is a discrete dinuclear copper(II) structure that linked by extensive hydrogen bonds to form a three-dimensional supramolecular structure. In the solid state, compound 1 exhibits blue photoluminescence with the maximum at 432 nm upon excitation at 350 nm. The temperature-dependent magnetic susceptibility data of 2 have been investigated. The Curie constant C and Weiss constant θ are 3.14 emu K mol −1 and −2.09 K, respectively, revealing antiferromagnetically magnetic interactions between the Mn 2+ ions. In addition, these compounds are characterized by powder X-ray diffraction, IR, elemental analysis, and thermogravimetric analysis.

UV–vis absorption properties of polyazomethine in base and protonated with 1,2-(di-2-ethylhexyl)ester of 4-sulfophthalic acid form

The UV–vis absorption properties of undoped and doped 1,4-phenylenemethylidynenitrilo-1,4-phenylenenitrilomethylidyne (PAZ) in various temperatures are reported. It is demonstrated that the absorption spectra can be modified not only by changing the temperature from 193 K to 413 K, but also via acid–base doping involving the protonation of nitrogen atom in imine group. The use of special protonating agent, i.e. 1,2-(di-2-ethylhexyl)ester of 4-sulfophthalic acid (PSA) lead to the modification of the absorption spectrum of the PAZ. The imine band in UV–vis spectrum of the doped with the PSA polyazomethine is 85 nm red shifts in comparison with unprotonated one. The thermochromism of PAZ included the conformational changes in the conjugating backbone structure of the undoped and doped polyazomethine.

Effect of Chain Structure and Dopant on the Thermal and Optical Properties of Conjugated—non-conjugated Isomeric Polyketanils

Two aryl-substituted, isomeric polyazomethines, termed polyketanils (PKs), were synthesized from 1,4-phenylenediamine or 1,8-diaminooctane and two different diketones, p-dibenzoylbenzene or 1,8-disebacoylbenzene via melt polycondensation with the purpose of obtaining new materials with tunable spectroscopic properties, mainly photoluminescence. It was found that the arrangement of the atoms in the diamine/diketone aliphatic sub-unit in the PKs influences their thermal and spectroscopic properties. It was demonstrated that the photoluminescence spectra can be modified not only by chain engineering but also via acid—base doping involving the protonation of ketimine groups. By combining these two methods it was possible to precisely tune the emission spectra of PKs in the spectral range of 480 to 550 nm. Furthermore, the use of bifunctional protonating agent 1,2-(di-2-ethylhexyl)ester of 4-sulfophthalic acid (DEHEPSA), containing plasticizing groups decreased the glass transition temperature ( T g) and also improved the flexibility of the polymer films. A concept for using the protonating agent, DEHEPSA, to achieve self-organization of PKs is introduced. The ordered structure of the (PKs)1(DEHEPSA) 2 complexes is discussed on the basis of Fourier transform infrared analysis, UV-vis absorption and photoluminescence.

Microwave synthesis and photophysics of new tetrasulfonated tin(II) macrocycles

This work reports on the microwave synthesis of tetrasulfonated tin phthalocyanine and tetrasulfonated tin α,β,γ-tetrabenzcorrole. The latter was only formed at low ratios (&lt;1:8) of 4-sulfophthalic acid to urea. Both complexes are aggregated in aqueous media, but can be partly or fully disaggregated by the addition of Triton X-100. The α,β,γ-tetrabenzcorrole complex has lower triplet life times and yields, while the binding constant and quenching (of bovine serum albumin) constant are lower for α,β,γ-tetrabenzcorrole compared to tetrasulfonated tin phthalocyanine.