Introduction Of Sulfonic Groups Research Articles

Sulfonated Graphene‐Based Materials as Heterogeneous Acid Catalysts for Solketal Synthesis by Acetalization of Glycerol

AbstractAcid catalysis plays a pivotal role in the industrial landscape due to its multifaceted contributions to various chemical processes in numerous sectors, including petrochemicals, polymers, food processing, and biodiesel production, among others. Sulfonated graphenes hold notable relevance as heterogeneous acid catalysts due to their unique combination of graphene's structural properties and the introduction of sulfonic groups as catalytic acid sites. Herein, we report the preparation of three sulfonated graphene‐based materials – sulfonated reduced graphene oxide (rGO‐SO3H), chlorosulfonated reduced graphene oxide (rGO‐HSO3Cl) and sulfonated graphene oxide (GO‐SO3H) – by different synthetic approaches. Physicochemical, textural, morphological, and acidic properties of all materials were characterized in detail by different instrumental techniques. Innovatively, these materials have been evaluated as heterogeneous acid catalysts in the solketal synthesis by acetalization of glycerol, which is considered an interesting building block to produce added‐value products. The density of acidic active sites and hydrophobicity were found to be conditioning parameters of the resulting catalytic activity in terms of conversion and selectivity. The best catalytic performance was obtained by rGO‐SO3H, reaching the maximum conversion towards solketal in 15 minutes under mild reaction conditions. The reusability and stability of all materials were also examined after three consecutive acetalization reactions with only a slight loss of catalytic activity.

Carbonyl‐Based Narrowband Emitters Peripherally Decorated by Sulfone‐Containing Spiro Structures

AbstractSulfone group plays a pivotal role in narrowing emission spectra, while, precise modification with sulfone group for carbonyl‐based narrowband emitters that maintain high color purity remains challenging. Herein, a comprehensive exploration of the function of the sulfone group is performed with various sulfur valences and positions fused into traditional carbonyl‐based narrowband emission unit QAO, namely SpiroS‐QAO, SpiroSO2‐QAO, SpiroO‐QAO, and SpiroOSO2‐QAO. A rigid molecular skeleton with a spiro structure as an intramolecular lock enables the four emitters to exhibit narrowband emissions. After full oxidization of sulfur, the emission band of SpiroSO2‐QAO is further narrowed, with full width at half maximum of 32 nm, compared to that of 43 nm for sulfane‐decorated SpiroS‐QAO, which is attributed to the suppressed C─S bond‐length variation by the introduction of sulfone group. Nearly identical spectra of SpiroO‐QAO and SpiroOSO2‐QAO suggest that the sulfone group should be directly linked to the emission core to maximize its function. Maximum external quantum efficiencies of 30.8%, 30.3%, and 29.2% are achieved for SpiroO‐QAO, SpiroOSO2‐QAO, and SpiroS‐QAO‐based sensitized organic light‐emitting diodes with highly efficient thermally activated delayed fluorescence assistant host. These results offer a comprehensive understanding of the sulfone group embedded into the narrowband emission core with respect to the narrowing emission band.

Fe3O4@SiO2 core/shell functionalized by gallic acid: a novel, robust, and water-compatible heterogeneous magnetic nanocatalyst for environmentally friendly synthesis of acridine-1,8-diones.

In this study, we conveniently prepared a novel robust heterogeneous magnetic nanocatalyst using a Fe3O4@SiO2 core/shell stabilized by gallic acid. The catalyst was completely characterized by various physicochemical techniques, including infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), potentiometric titration, energy dispersive X-ray microanalysis (EDX), vibrating sample magnetometer (VSM), zeta potential analysis, and BET. The potential ability of the newly developed sulfonated nanocatalyst was then exploited in the multicomponent synthesis of acridine-1,8-dione derivatives by considering the green chemistry matrix and under mild conditions. Various aldehydes and amines were smoothly reacted with dimedone, affording the desired products in good to excellent yields. The introduction of sulfonic groups using gallic acid allowed the development of a water-compatible and highly recyclable catalytic system for reactions in an aqueous environment. The prepared catalyst can be readily magnetically separated and reused eight times without significant loss of activity. High synthetic efficiency, using a recyclable and eco-sustainable catalyst under mild conditions, and easy product isolation are salient features of this catalytic system, which makes this protocol compatible with the demands of green chemistry.

Design of bioactive and biomimetic scaffolds based on chitosan-alginate polyelectrolyte complexes for tissue engineering

The replacement and regeneration of biological tissues by fabricating three-dimensional functionalized constructs that can improve material interaction with cells is an important challenge of tissue engineering. In this study, bioactive and biomimetic scaffolds based on chitosan-alginate polyelectrolyte complexes (PECs) were fabricated by freeze-drying method and then crosslinked with CaCl2. Various chitosan-alginate (CS-AL) molar ratios were used to obtain PECs with different structural and mechanical properties. The CS1-AL2.3 scaffold showed to possess the best mechanical properties (8 MPa) and good pore morphology with an average size of 100–150 μm. After the crosslinking process, a less porous structure but with higher elastic modulus (30 MPa) was obtained. To make matrix bioactive and biomimetic, the CS1-AL2.3 system was first functionalized with 3,4-dihydroxyhydrocinnamic acid (HCAF) and then with PySO3 or Heparin to introduce groups/molecules mimicking the extracellular matrix. While the antioxidant properties of the scaffolds containing HCAF improved by 3 orders of magnitude, compared to the non-functionalized matrix, the introduction of sulfonic groups into the bioactive scaffold made the structure more porous and hydrophilic with respect to the heparinized one also favoring the penetration and proliferation of fibroblasts into the scaffold. These results indicate the potential of these novel systems for tissue engineering.

Preparation and Properties of Sulfonated Poly(phthalazinone ether ketone) Membranes for Electrodialysis.

Sulfonated poly(phthalazinone ether ketones) (SPPEK) with ion exchange capacities from 0.77 to 1.82 mmol·g−1 are synthesized via an electrophilic substitution reaction. Nuclear magnetic resonance and infrared absorption spectroscopy are used to characterize the chemical structure of the obtained polymers for confirming the successful introduction of sulfonic groups. SPPEKs show excellent thermal stability; their temperature required to achieve 5% weight loss is about 360 °C. Accordingly, the obtained membranes possess high ion perm-selectivity, proton conductivity, and low area resistance. Regarding the electrodialysis-related performance of the membranes, the SPPEK-4 membrane has the highest limiting current density (39.8 mA·cm2), resulting from its high content of sulfonic groups. In a desalination test of standard solution, SPPEK-3 and SPPEK-4 membranes exhibit both better salt removal rate and acceptable energy consumption than commercial membrane. Additionally, SPPEK-3 membrane shows outstanding performance in terms of high concentration rate and low energy consumption during saline water treatment, which indicates the feasibility of novel membranes in electrodialysis application.

Sustainable biofuel production from non-edible oils utilizing modified montmorillonite based porous clay heterostructures

ABSTRACT Surface modification was performed for montmorillonite clay by grafting phenyl triethoxy silane moiety followed by sulfonation to obtain the heterogeneous acidic catalyst. The prepared catalyst was recognized using numerous analytical procedures. FTIR spectra inspected the functional groups of the original clay and gave an insight view on the sulfonated clay. XRD provided information on sulfonation of original clay by the shifting of signals at 2θ at 18.5°, 26.55°, and 61.89° peaks to 17.8° (003), 25.5° (003). TPD profile showed the presence of different acidic sites on the surfaces of the studied compounds identified as weak, moderate, and strong types; further, the sulfonation step generated high intensity of the strong acidic sites on the clay surface. Surface area analysis showed that the introduction of sulfonate moieties within the clay framework crowded the pores and decreased their effective area and volume to 66.31 m2/g and 0.11 cm3/g. TGA identification indicated that the introduction of sulfonate groups within the clay framework increased its thermal stability by up to 600°C, due to the hydrogen bonding between the hydroxyl groups of clay and sulfonate groups. The analyses pointed out the successful grafting and sulfonation on the clay. The prepared catalyst was employed during catalytic conversion of used cooking oil and Jatropha oil into their corresponding biofuels. B10 blends of Jatropha oil and used cooking oil by petroleum Jet A-1 have exhibited densities at 0.8037 and 0.8040 g/cm3, while flashpoints were 46°C and 46°C, also the freeze points were also identical at −54 oC. The yield % of Jatropha oil and used cook oil biofuels using the optimum catalyst ratio (0.8% by weight) were 95% and 86%. The biofuels and their blend specifications were measured and compared using the fossil diesel Jet A-1.

Post-oxidation of a fully conjugated benzotrithiophene-based COF for photocatalytic detoxification of a sulfur mustard simulant

Through the introduction of sulfone groups, BTT-TPh-O-COF shows a 5-fold enhancement for the photocatalytic detoxification of a sulfur mustard simulant, and was further used to fabricate highly active composite protective films.

Recent Progress on the Synthesis of Chiral Sulfones.

Chiral sulfones extensively exist in drugs, agricultural chemicals, chiral organic intermediates, and functional materials. Their importance causes the rapid development of their synthetic methods in recent years. Many transition metal complex catalysts with chiral ligands and chiral organocatalysts are adopted in synthesis of chiral sulfones. Most of the methods to construct chiral sulfones are based on the reduction of unsaturated sulfones and the introduction of sulfone groups into unsaturated hydrocarbons. This review describes all classes of asymmetric reactions for synthesis of chiral sulfones.

Sorption Properties of Polydivinylbenzene Polymers Towards Phenolic Compounds and Pharmaceuticals

Highly cross-linked polymers are commonly used in purification and separation techniques because of their many useful features. In order to better adjust their porosity to adsorption of specific compounds, methods like surface functionalization or imprinting are used. In this work, a series of highly cross-linked polydivinylbenzenes (pDVB) were prepared using a suspension method. Toluene was applied as a pore-forming diluent. Some part of toluene (1 mL) was replaced with phenol (F), 2,4,6-trichlorophenol (T) or their mixture (M) to prepare polymers with porosity more suitable for phenols sorption. Another approach was an introduction of sulfone groups onto the polymer surface (pDVB-SO3H). The physicochemical characteristics of the synthetized adsorbents included CHN, FTIR, DSC and porosimetric analyses. Afterwards, to evaluate sorption properties of the prepared adsorbents towards phenols, ibuprofen and salicylic acid the solid phase extraction (SPE) experiments were performed. The polymers had the specific surface areas of about 440–560 m2/g created mainly by mesopores with widths ca. 3.75 and 4.75–7.15 nm. Materials obtained with the addition of porosity modifiers (phenol, trichlorophenol, mixture) had more uniform porous structure and their sorption capacity toward phenols increased ca. 5%. Similar sorption capacities were obtained for ibuprofen. Salicylic acid had low affinity to the surface of the tested polymers.

Mechanical Properties and Wear Resistance of Sulfonated Graphene/Waterborne Polyurethane Composites Prepared by In Situ Method.

In order to improve the dispensability of graphene oxide (GO) in waterborne polyurethane (WPU), sulfonated graphene (SGO) with superior dispersity was prepared by modifying graphene oxide with sodium 2-chloroethane sulfonate to introduce hydrophilic sulfonic groups into the structure. SGO/WPU composites were prepared using isophorone diisocyanate (IPDI), polytetramethylene ether glycol (PTMEG 2000), dimethylolpropionic acid (DMPA) and SGO as raw materials. The influence of SGO content on composite properties were investigated. The structure and morphology of SGO and SGO/WPU composites were characterized by infrared spectroscopy, X-ray diffractometry and transmission electron microscopy etc. Their mechanical properties and wear resistance were analyzed as well. The experimental results showed that SGO was successfully grafted onto polyurethane macromolecule by an in situ method and, with the introduction of sulfonic groups, the interfacial compatibility of GO and PU was improved significantly so that SGO evenly dispersed into WPU. The SGO that was grafted onto WPU macromolecules exhibited layered morphology with nanometers in the WPU matrix. With increasing SGO content, the tensile strength and the wear resistance of the film increased, but the addition of more than 0.8 wt % SGO yielded unfavorable results. When the added amount of SGO was 0.8 wt % of WPU, the tensile strength of the composite film was 46.53% higher than that of the blank group, and the wear resistance of the film was remarkably improved, which was due to a strong interaction between the SGO and WPU phases. Thus, the conclusion can be drawn that appropriate amount of SGO addition can enhance the mechanical properties of SGO/WPU composite film.

Chemically Modified Polyvinyl Chloride for Removal of Thionine Dye (Lauth's Violet).

The chemical modification of hydrophobic polymer matrices is an alternative way to elchange their surface properties. The introduction of sulfonic groups in the polymer changes the surface properties such as adhesion, wettability, catalytic ability, and adsorption capacity. This work describes the production and application of chemically modified polyvinyl chloride (PVC) as adsorbent for dyes removal. Chemical modification of PVC was evaluated by infrared spectroscopy and elemental analysis, which indicated the presence of sulfonic groups on PVC. The chemically modified PVC (PVCDS) showed an ion exchange capacity of 1.03 mmol−1, and efficiently removed the thionine dye (Lauth’s violet) from aqueous solutions, reaching equilibrium in 30 min. The adsorption kinetics was better adjusted for a pseudo second order model. This result indicates that the adsorption of thionine onto PVCDS occurs by chemisorption. Among the models for the state of equilibrium, SIPS and Langmuir exhibited the best fit to the experimental results and PVCDS showed high adsorption capacities (370 mg−1). Thus, it is assumed that the system presents homogeneous characteristics to the distribution of active sites. The modification promoted the formation of surface characteristics favorable to the dye adsorption by the polymer.

The effect of sulfonate groups on spectral-luminescent and photovoltaic properties of squarylium dyes

Abstract Squarylium dye with sulfonate groups has been synthesized and its spectral-luminescent and photovoltaic properties have been studied in comparison with its non-functionalized analogue. It has been demonstrated that the introduction of sulfonate groups in the indolenine heterocycle of squarylium dyes results in the bathochromic shifts of the absorption and fluorescence band. In so doing, the fluorescence quantum efficiency and extinction coefficients of the dyes are virtually independent of the functional groups presence. A fluorescent quantum yield of dyes has been measured on the semiconductor and dielectric surface. It has been shown that the introduction of anchor sulfonate groups in the structure of the dye provides a more intimate contact with TiO 2 nanoparticles which increases the number of charge carriers transferred from the dye to the semiconductor. This phenomenon can be effectively used for the dye-sensitized solar cells (DSSC).

Friedel-Crafts arylmethylation: A simple approach to synthesize bipolar host materials for efficient electroluminescence

Abstracts In order to simplify the synthesis of bipolar host materials of OLEDs, a facile synthetic approach was developed and a series of sulfone-contained bipolar host materials were synthesized via mild one-step Friedel-Crafts arylmethylation. Due to π-conjugate-interrupted connection between donor moiety and sulfone moiety, those materials keep high triplet energy and separate the HOMO and LUMO levels. Furthermore, the introduction of sulfone group can significantly lower LUMO level. Based on newly synthesized sulfone-based bipolar host materials, efficient solution-processed sky-blue phosphorescent OLEDs were fabricated with high current efficiency of 16.5 cd/A. Our results demonstrate Friedel-Crafts arylmethylation is powerful synthetic strategy to construct bipolar host materials.

Blood protein adsorption on sulfonated chitosan and κ-carrageenan films

Many strategies have been reported to improve compatibility of biopolymers using chemical and physical modifications. One possibility is the introduction of sulfonate groups (R-SO3−) in the chitosan chain. Another biopolymer with similar characteristics to those of heparin is κ-carrageenan. This study proposed to investigate the application of these two polymers, based on their potential for globular protein adsorption (BSA and fibrinogen). Polymeric films of chitosan and κ-carrageenan were prepared; all films were characterized by elemental analyses, FTIR, XPS and SEM. Characterization techniques showed that the chitosan chain was modified and confirmed the existence of sulfonate groups, as well as in the κ-carrageenan chain, indicating surfaces with similar chemical properties to those of heparin. The effect of charge density was observed for each adsorption condition (BSA at pH 5.0 and 7.4). A more pronounced adsorption rate was observed at pH 5.0 than at pH 7.4 and equilibrium adsorption was achieved, in both cases, after approximately 20min. The equilibrium data indicate a lower adsorption rate for the sulfonated chitosan film, in comparison to the other films. These results confirm the potential of modified chitosan for use in applications in which globular protein adsorption should be avoided.

Effect of copolymerization and semi-interpenetration with conducting polyanilines on the physicochemical properties of poly( N-isopropylacrylamide) based thermosensitive hydrogels

Thermosensitive hydrogels are made by radical homopolymerization of N-isopropylacrylamide (NIPAAM) or copolymerization of NIPAAM with 2-acrylamido-2-methyl-propane sulfonic acid (AMPS). The networks are semi-interpenetrated (s-IPN) with linear conducting polymers: polyaniline (PANI) or poly( N-methylaniline) (PNMANI). The semi-interpenetration affect slightly the phase transition temperature (measured by DSC) of the hydrogels, while water uptake capacity is strongly affected and depends on the relative hydrophobicity of the conducting polymer. Since polyanilines can be protonated in aqueous media, the swelling capacity of the s-IPN hydrogel depends strongly on pH unlike the unmodified hydrogel. The release of a model compound (tris(2,2′-bipyridine)ruthenium (II), Ru ( bpy ) 3 + 2 ), driven by swelling or temperature, is also strongly affected both by the introduction of sulfonic groups, by copolymerization of NIPAAM with AMPS, semi-interpenetration and on the hydrophobicity of the conducting polymer. In that way, composite materials with quite different ion exchange behavior can be made by copolymerization and conducting polymer interpenetration.

Zeolite beta-filled chitosan membrane with low methanol permeability for direct methanol fuel cell

Zeolite beta particles with different sizes and narrow size distribution were hydrothermally synthesized and incorporated into chitosan (CS) matrix to prepare CS/zeolite beta hybrid membranes for direct methanol fuel cell (DMFC). It was found that the chitosan membrane filled by zeolite beta particles about 800 nm in size exhibited the lowest methanol permeability, which can be ascribed to their optimum free volume and methanol diffusion characteristics. To further improve the performances of CS/zeolite beta hybrid membranes, zeolite beta particles about 800 nm in size were sulfonated via three different approaches. The results indicated that the introduction of sulfonic groups could reduce the methanol permeability further as a result of the enhanced interfacial interaction between zeolite beta and chitosan matrix. Furthermore, in terms of the overall selectivity index, CS/zeolite beta hybrid membranes were comparable to Nafion ® 117 membrane at low methanol concentration (2 mol L −1) and much better at high methanol concentration (12 mol L −1).

Hybrid membranes based on block co-polymer ionomers and silica gel. Synthesis and characterization

This work reports on the synthesis (via heterogeneous sulfonation) structural and electrical characterization of hybrid membranes based on block co-polymer ionomers (HSBR and EPDM) and silica gel prepared by sol–gel reaction.The structural characterization consisted of the analysis of their thermal and mechanodynamical transitions by DSC and DMA, respectively. The ion-exchange capacity of each polymer was determined by both titration and elemental analysis (EA). The introduction of sulfonic groups was verified by means of infrared spectroscopy (ATR). The electrical characterization was made using ac impedance at different hydration times, the conductivity being calculated from the corresponding impedance spectra. Finally, methanol crossover through the membranes was carried out, comparing the results obtained with Nafion 117.The results indicate the existence of a complex microstructure formed by different phases corresponding to both ionic and non-ionic blocks of the co-polymer as well as the aggregates or clusters owed to the electrostatic interaction among ion pairs. Conductivity values are similar to Nafion and they improve with hydration time for hybrid membranes due to the absorbent nature of the inorganic filler. Likewise, methanol crossover is lower than in Nafion, probably due to the barrier effect exerted by the non-sulfonated blocks of the co-polymer.

Rheological and mechanical properties of DGEBA-S epoxy copolymer initiated byN-benzylquinoxalinium hexafluoroantimonate

The rheological and mechanical properties of the DGEBA-S epoxy copolymer initiated by N-benzylquinoxalinium hexafluoroantimonate (BQH) as a cationic latent thermal catalyst were investigated. The rheological properties of the DGEBA-S/BQH system were investigated using a rheometer under isothermal conditions, and the mechanical properties of the casting specimens, involving flexure and impact tests, were also performed. The crosslinking activation energy and mechanical properties of the DGEBA-S/BQH system were higher than those of the DGEBA/BQH system. This could be attributed to the introduction of sulfone groups with a polar nature to the main chain of the epoxy resins which led to a decrease of molecular motion and an improvement in the toughness of the cured epoxy copolymers. Copyright © 2005 Society of Chemical Industry

Processing, characterization and properties of conducting polyaniline-sulfonated SEBS block copolymers

Incorporation of polyaniline (PAni) into thermoplastic elastomers can be used to produce materials that potentially combine the good mechanical properties and processability of thermoplastic elastomers with electrical, magnetic and optical characteristics of PAni. In this work, a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene copolymer (SEBS) was chemically modified by grafting a sulfonic group onto the chain backbone in order to promote higher levels of compatibility between the thermoplastic elastomer and polyaniline. The sulfonation process was performed by reacting SEBS with acetyl sulfate. Infrared spectroscopy and titration were used to monitor the amount of sulfonic groups successfully grafted on SEBS. Mechanical tests performed in sulfonated SEBS showed that sulfonation levels lower than 15% did not reduce substantially the mechanical properties of SEBS. PAni doped with dodecylbenzenesulfonic acid (PAni·DBSA), used in the preparation of the blends, was prepared by the “ in situ doping polymerization” method. PAni·DBSA was then blended in solution with SEBS having different levels of sulfonation. The introduction of sulfonic group into the structure of SEBS improved coulombic interactions between the phases in the blend and enhanced compatibility. As a consequence, higher values of electrical conductivity (measured by the four-probe method) were achieved in blends with sulfonic groups grafted onto polymer chains. Concentrations as low as 20 wt% of PAni were able to lead to electrical conductivities of PAni·DBSA/sulfonated SEBS blends close to 1.2 S/cm. Optical micrographs of the blends showed that PAni·DBSA/sulfonated SEBS microstructure is composed of a very disperse group of small conducting particles. This type of microstructure would then be responsible for the enhanced electrical conductivity and low percolation threshold of PAni·DBSA/sulfonated SEBS, when compared to PAni·DBSA/SEBS blends.

Physical and Mechanical Interfacial Properties of Epoxy Copolymers Initiated by Latent Thermal Catalysts

AbstractSummary: The epoxy copolymers containing sulfone groups, diglycidyl ether of bisphenol‐A – Bisphenol‐S (DGEBA‐S) were synthesized by a hot‐melt method. The thermal properties of the epoxy systems initiated by two cationic latent catalysts, i.e., N‐benzylpyrazinium hexafluoroantimonate (BPH) and N‐benzylquinoxalinium hexafluoroantimonate (BQH), were investigated by using a dynamic DSC, DMA, and TGA. The mechanical properties were measured by single‐edge‐notched (SEN) beam fracture toughness tests. As a result, the thermal stability and mechanical interfacial properties of the DGEBA‐S/catalyst system were found to be higher than those of the DGEBA/catalyst. This was probably due to the fact that the introduction of sulfone groups with a polar nature to the main chain of the epoxy resins led to an improvement of thermal stability and toughness of the cured epoxy copolymers.Conversion of the epoxy/catalyst systems as a function of curing temperature.imageConversion of the epoxy/catalyst systems as a function of curing temperature.