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The reaction of hydrazinium sulfate and chlorosulfonic acid in pyridine leads to the pyridinium salt of the hydrazine disulfonate anion, [(SO3)HNNH(SO3)]2−. The salt is the starting material for the preparation of further hydrazine disulfonates, for example of alkaline metals and barium. In all compounds, the [(SO3)HNNH(SO3)]2− anion adopts the gauche conformation. The conformer is chiral but all of the investigated compounds crystallize as racemates. The disulfonate anion can occur in another constitution with the two sulfonate groups attached to only one nitrogen atom. This so‐called hydrazine iso‐disulfonate, [H2NN(SO3)2]2−, has been prepared through a substitution reaction between potassium imidodisulfonate, K2[HN(SO3)2], and hydroxylamine‐O‐sulfonic acid, H2NOSO3H. The hydrazine iso‐disulfonate anion has been crystallized as potassium and barium compound, respectively. The compounds were characterized by XRD, vibrational spectroscopy, DFT calculations and thermal analyses. [ABSTRACT FROM AUTHOR]

The reaction of hydrazinium sulfate and chlorosulfonic acid in pyridine leads to the pyridinium salt of the hydrazine disulfonate anion, [(SO3)HNNH(SO3)]2−. The salt is the starting material for the preparation of further hydrazine disulfonates, for example of alkaline metals and barium. In all compounds, the [(SO3)HNNH(SO3)]2− anion adopts the gauche conformation. The conformer is chiral but all of the investigated compounds crystallize as racemates. The disulfonate anion can occur in another constitution with the two sulfonate groups attached to only one nitrogen atom. This so‐called hydrazine iso‐disulfonate, [H2NN(SO3)2]2−, has been prepared through a substitution reaction between potassium imidodisulfonate, K2[HN(SO3)2], and hydroxylamine‐O‐sulfonic acid, H2NOSO3H. The hydrazine iso‐disulfonate anion has been crystallized as potassium and barium compound, respectively. The compounds were characterized by XRD, vibrational spectroscopy, DFT calculations and thermal analyses. [ABSTRACT FROM AUTHOR]

A Z-scheme heterojunction photo(electro)catalyst was fabricated by coupling sulfonic acid-modified graphitic carbon nitride (SA-g-CN) with bismuth oxyiodide (BiOI). The SA-g-CN component was prepared via wet-impregnation, while BiOI was synthesized through a hydrothermal method. Comprehensive characterization elucidated the structural and morphological properties of the resulting composite. The SA-g-CN/BiOI exhibited exceptional performance in both photocatalytic degradation of tartrazine (TTZ) and photoelectrochemical oxygen evolution reaction (OER). Notably, 98.26% TTZ removal was achieved within 60 min of irradiation, while an OER onset potential of 0.94 V (vs. Ag/AgCl) and a high photocurrent density of 6.04 mA were recorded under AM 1.5G illumination. Band energy calculations based on Mott–Schottky measurements confirmed the formation of a Z-scheme heterojunction, which facilitated efficient charge separation and transfer, thereby enhancing catalytic activity. These findings establish the SA-g-CN/BiOI composite as a promising candidate for sustainable energy generation and environmental remediation applications. [ABSTRACT FROM AUTHOR]

In this paper, the design, synthesis and catalytic application of a magnetic covalent organic framework modified with sulfonic acid (Fe3O4@COF-SO3H) in the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives, were studied. The structure of the prepared catalyst was confirmed by various techniques including Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy, thermo-gravimetric analysis, field emission scanning electron microscopy, vibrating-sample magnetometer and Brunauer–Emmett–Teller porosimetry. The structure of the prepared derivatives was also confirmed using FT-IR and nuclear magnetic resonance (1HNMR and 13CNMR) spectroscopy. Facile synthesis, solvent-free conditions, high yield, short reaction time, eco-friendly procedure, and straightforward work-up are among the advantages of this research. [ABSTRACT FROM AUTHOR]

Fe3O4@APIDSO3H as a novel and magical magnetic nanocatalyst was designed, synthesized, and characterized by different spectroscopic techniques such as Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x‐ray diffraction (XRD), energy‐dispersive x‐ray (EDX), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The loading percentage of sulfonic acid on the magnetic nano catalyst was calculated using CHNS analysis. Then, the potential use of it was investigated for the synthesis of various coumarins by Pechmann condensation. The corresponding products were synthesized and isolated in 60%–99% yields. The catalyst was recycled and reused for four times without loss in catalytic activity. [ABSTRACT FROM AUTHOR]

Understanding and controlling the sintering behaviour of gold nanoparticles is important in the field of ligand-protected nanoparticles for their use as precursors for thin film fabrication. Lowering the temperature of the sintering event of gold nanoparticles by facilitating desorption of the ligand through oxidation can provide compatibility of sintered gold nanoparticle thin films onto heat-sensitive substrates. Here we examine the processes by which 1-butanethiol-protected gold nanoparticles sinter under an ozone-rich environment. Upon heating, an ozone-rich environment significantly reduces the temperature of the sintering event when compared to sintering under ambient conditions. At room temperature, exposure to an ozone-rich environment induces sintering over a period of 2.5 h. Upon exposure to ozone, the surface-bound butanethiol ligands are oxidised to 1-butanesulfonic acid which facilitates sintering. [ABSTRACT FROM AUTHOR]

New polyfunctional compounds of the pinane series, 2-carboxy-3-thioacetate, 2-carboxy-3-sulfonyl chloride, and 2-carboxy-3-sulfonic acid that are promising intermediate products in organic synthesis, were synthesized for the first time by the reaction of S-(1S,2R,3S,5R)-(6,6-dimethyl-2-formylnorpinan-3-yl) thio-acetate with chlorine dioxide. The major reaction pathway in nonpolar solvents involves oxidation of the aldehyde group to carboxy, whereas oxidation of the sulfur atom, followed by deacetylation, occurs in highly polar solvents. The effect of VO(acac)2 as catalyst on the reaction chemoselectivity in weakly polar diethyl ether was revealed. [ABSTRACT FROM AUTHOR]

Sonochemistry under controlled conditions has proven effective in medicinal chemistry and drug development. It can substantially shorten reaction timelines from days or hours to minutes. A convenient one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazole derivatives catalyzed by PTSA and benzenesulfonic acid in ethanol as solvent, under ultrasonic irradiation and without ultrasound irradiation at 50° C has been achieved successfully. These 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazole derivatives synthesis were also accomplished using different solvents viz., Methanol, Ethanol, DCM, DMF, Acetonitrile and THF and PTSA as the catalyst. This method yielded the highest % synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazole derivatives with PTSA as the catalyst in solvent ethanol. These reactions were also optimized for % of PTSA catalyst required to obtain the maximum yield of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazole derivatives with and without ultrasound irradiation at 50° C. Synthesis of 2,4,5-trisubstituted Imidazole derivatives reaction follows first-order rate kinetics while that of 1,2,4,5-tetrasubstituted Imidazole derivatives reaction follows the second-order rate kinetics. Furthermore, sonochemistry has higher yields, lower cost, easier workups, and higher purity than conventional thermal organic synthesis, which has lower yields, tedious workups, longer reaction periods, lower purity, and numerous byproducts. [ABSTRACT FROM AUTHOR]

A Z-scheme heterojunction photo(electro)catalyst was fabricated by coupling sulfonic acid-modified graphitic carbon nitride (SA-g-CN) with bismuth oxyiodide (BiOI). The SA-g-CN component was prepared via wet-impregnation, while BiOI was synthesized through a hydrothermal method. Comprehensive characterization elucidated the structural and morphological properties of the resulting composite. The SA-g-CN/BiOI exhibited exceptional performance in both photocatalytic degradation of tartrazine (TTZ) and photoelectrochemical oxygen evolution reaction (OER). Notably, 98.26% TTZ removal was achieved within 60 min of irradiation, while an OER onset potential of 0.94 V (vs. Ag/AgCl) and a high photocurrent density of 6.04 mA were recorded under AM 1.5G illumination. Band energy calculations based on Mott–Schottky measurements confirmed the formation of a Z-scheme heterojunction, which facilitated efficient charge separation and transfer, thereby enhancing catalytic activity. These findings establish the SA-g-CN/BiOI composite as a promising candidate for sustainable energy generation and environmental remediation applications.

Betulin is a biologically active triterpenoid substance, which can be isolated from birch bark. We report on a new approach to the synthesis of betulin sulfamate with sulfamic acid and ammonium sulfamate in the presence of solid catalysts, including Amberlyst 15® and Sibunit (granules) oxidized at 500 °C, Sibunit (powder) oxidized at 400 °C, Sibunit-sulfated, TiO2, and ɣ-Al2O3. It is shown that the synthesis with both sulfamic acid and ammonium sulfamate in the presence of an Amberlyst 15® catalyst yields sulfur derivatives of betulin. This catalyst has been proven to remain active at the repeated (up to four cycles) use. A reaction scheme for the catalytic production of sulfur derivatives of betulin is proposed. The obtained sulfur derivatives of betulin have been examined by Fourier transform infrared and ultraviolet visible spectroscopy, scanning electron and optical microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, and elemental analysis. It has been found by Fourier transform infrared spectroscopy that the use of sulfamic acid with an Amberlyst 15® catalyst ensures the formation of betulin sulfates, while when using ammonium sulfamate with the same catalyst, the sulfate and other betulin derivatives are obtained along with sulfates. It has been established from the X-ray diffractometry data that sulfation of betulin causes its stronger amorphization. [ABSTRACT FROM AUTHOR]

Porous polytetrafluoroethylene (PTFE) reinforced sulfonic acid-based proton exchange membranes (PEMs) are widely used for proton exchange membrane fuel cells (PEMFCs) due to their superior mechanical durability compared with pristine/free-standing sulfonic acid-based PEMs. However, the development of advanced porous PTFE reinforced sulfonic acid-based PEMs (PTFE-PEMs) still faces some technical challenges, including poor ionomer filling, poor interface bonding between PTFE skeleton and ionomer, limited chemical durability, inferior performance at low humidity, limited interface combination between PTFE-PEMs and catalyst layers, and unclear effect of the number of PTFE skeleton layers. Extensive research has been implemented to overcome these scientific issues, thus realizing the practical prospects of PTFE-PEMs. Nevertheless, relevant summary about these studies is scarce. On this basis, this paper highlights the technical challenges of PTFE-PEMs and reviews the research advances in solving these scientific issues of PTFE-PEMs. In addition, the challenges and future perspectives of PTFE-PEMs are also discussed. The systematic summary and proposed directions can trigger thoughts and provide ways to reasonably design PTFE-PEMs for PEMFCs in the near future. [Display omitted] • Fundamentals of porous PTFE reinforced SA-PEMs are introduced. • Technical challenges of PTFE-PEMs are summarized. • Research advances in PTFE-PEMs are reviewed. • Challenges and future development on PTFE-PEMs are discussed. [ABSTRACT FROM AUTHOR]

The reaction of hydrazine hydrate, N2H4 ⋅ H2O, and SO3 leads to hydrazine sulfonic acid (Pca21, a=849.59(4) pm, b=482.18(2) pm, c=832.17(4) pm). Structure elucidation reveals the zwitter‐anionic nature of the compound according to NH3NH(SO3). With the barium salt Ba[NH2NH(SO3)]2(H2O), a first salt of hydrazine sulfonic acid has been prepared (P1‾ $\bar 1$ , a=489.75(5) pm, b=737.52(7) pm, c=1317.4(1) pm, α=88.238(4)°, β=84.761(4)°, γ=79.701(4)°). The compounds were characterized by vibrational spectroscopy, DFT calculations and thermal analyses. [ABSTRACT FROM AUTHOR]

Highly sulfated malto-oligomers, similar to heparin and heparan-sulfate, have good antiviral, antimetastatic, anti-inflammatory and cell growth inhibitory effects. Due to their broad biological activities and simple structure, sulfated malto-oligomer derivatives have a great therapeutic potential, therefore, the development of efficient synthesis methods for their production is of utmost importance. In this work, preparation of α-(1→4)-linked oligoglucosides containing a sulfonatomethyl moiety at position C-6 of each glucose unit was studied by different approaches. Malto-oligomeric sulfonic acid derivatives up to dodecasaccharides were prepared by polymerization using different protecting groups, and the composition of the product mixtures was analyzed by MALDI-MS methods and size-exclusion chromatography. Synthesis of lower oligomers was also accomplished by stepwise and block synthetic methods, and then the oligosaccharide products were persulfated. The antiviral, anti-inflammatory and cell growth inhibitory activity of the fully sulfated malto-oligosaccharide sulfonic acids were determined by in vitro tests. Four tested di- and trisaccharide sulfonic acids effectively inhibited the activation of the TNF-α-mediated inflammatory pathway without showing cytotoxicity. [ABSTRACT FROM AUTHOR]

Current work reports the highly selective, solvent‐free synthesis of an endorsed bioactive compound, Bis benzylidine cyclohexanone (BBC) through solid acid catalysed cross aldol condensation route and checks its in‐vitro bio activity. The catalytic support (Multiwalled carbon nanotube) employed was synthesized through the highly sophisticated catalytic chemical vapor deposition (CVD) method and simple mechanical grinding strategy was adopted to decorate sulfonic acid on the support. The C1s X‐ray photoelectron peak of at 290.3 eV confirms the effective interaction of sulfonic acid with MWCNT. The sharp and intense desorption peaks observed at approximately 528.7 °C and 655.15 °C in the TPD analysis unmistakably substantiate the strong acidity of the synthesized system. The alpha amylase inhibition activity of the synthesized compound was calculated to be around 88.5 %, which is in par with the commercial drug as it could inhibit only 96 %. Further, the in‐silico (Docking and Molecular Dynamic Simulation) investigations unveiled a new target site for the compound and this can further be studied in detail to advance the applications in drug design. Detailed scrutiny of various parameters was conducted to validate the bioactivity and pharmaceutical potential of the synthesized compound. [ABSTRACT FROM AUTHOR]

The present work describes an advanced cross‐coupling reaction of vinyl sulfonates for the synthesis of sulfonic acid salts and sulfonic acids under mild reaction conditions. The regioselectivity of the double Negishi reaction was achieved by means of the different reactivity of the C−Br and activated C−O bonds. The cross‐coupling reaction leads to a mixture of alkenes and sulfonic acid salts. The separation of alkenes and sulfonic acid salts is achieved through the low solubility of sulfonic acid sodium salts after workup. In addition, the developed procedure is also used for the atom‐economical preparation of cyclooxygenase‐2 inhibitors (COX‐2). [ABSTRACT FROM AUTHOR]

Developing polymer carrier catalysts is an important topic for effectively addressing catalyst utilization and green synthetic chemistry. As a monomer, allylamine hydrochloride is polymerized with initiation to obtain polyallylamine which is cross-linked with epichlorohydrin to obtain cross-linked polyallylamine hydrochloride. Using cross-linked polyallylamine as a carrier, a solid acid catalyst with high loading is prepared by reacting with chlorosulfonic acid. The cross-linked polyallylamine sulfonic acid catalyst is stable up to 150 ℃, indicating its excellent thermal stability. This catalyst is used to catalyze the reaction of benzoic acid and n-butanol to produce n-butyl benzoate. The optimal reaction conditions are: the molar ratio of n-butanol to benzoic acid of 2∶1, the catalyst dosage of 20 g/mol BA, reaction temperature of 120 ℃ and reaction time of 6 h. The esterification rate of benzoic acid is 95%. This catalyst can be reused up to 4 times while maintaining high catalytic performance. [ABSTRACT FROM AUTHOR]

To expand the application of novel nanomaterial based solid phase extraction technology in complex food matrices, a sulfonic acid based covalent organic framework (TpPa-SO3H) was prepared as solid phase extraction adsorbents for the rapid analysis of three fluoroquinolones (FQs) antibiotics in milk by using high performance liquid chromatography (HPLC). TpPa-SO3H was rapidly prepared by mechanical grinding, and its merits as novel solid phase adsorbents with high efficiency were fully explored in the detection towards FQs antibiotics. The effect of adsorbent dosage, pH of sample solution, adsorption time and desorption conditions were investigated to determine the effect of nanomaterial structure and properties on the solid phase extraction efficiency and the reproducibility with quantitative analysis capacity of this method. The results showed that TpPa-SO3H possessed large specific surface area and abundant sulfonic acid functional sites, which could combine with FQs antibiotics efficiently and selectively. Under optimal operation conditions, the extraction recovery of three FQs antibiotic were in the range of 94.23%～98.68% within 4.0 min, which was significantly better than the national standard method. Thus a new high performance liquid chromatography (HPLC) method for the rapid analysis of FQs antibiotics in milk was established based on TpPa-SO3H solid phase extraction, and the method owned the advantages of high sensitivity, excellent anti-interference ability, good repeatability, simplicity and rapidity. The detection limit of the three FQs antibiotics were in the range of 0.002～0.004 mg/kg, indicating that the method could be used for the detection of ultra-trace FQs antibiotics in real samples. In conclusion, the solid phase extraction combined with HPLC based on TpPa-SO3H has realized the rapid detection of trace FQs antibiotics in milk with high sensitivity and selectivity, which indicating its great potential in scientific research and practical application.

Ammonia is a promising carbon-free fuel, but current methods to produce ammonia are energy intensive. New methods are thereby needed, with one promising method being electrochemical nitrogen reduction cells. Efficient cell operation requires robust catalysts but also efficient membrane separators that permit the selective transport of ions while minimizing the transport of the products across the cell. Commercial membranes have an unknown morphology which makes designing improved cells challenging. To address this problem, we synthesized a series of membranes with controlled crosslinking density and chemical composition to understand their impact on ammonium transport. Higher crosslinking density led to lower ammonium permeability. At the highest crosslinking density, similar ammonium permeability was observed independent of the water volume fraction and hydrophobicity of the monomers. These results suggest new directions to develop membranes with reduced ammonium crossover to improve the efficiency of these electrochemical cells.

A simple and straightforward synthetic strategy has been established toward furnishing of promising bis-heterocyclic pyrazole containing substituted tetrazole derivatives which might be proved as valuable molecules because of the presence of medicinally and biologically important pyrazole and tetrazole entities. Sulfonic acid decorated graphene oxide (GO-SO3H), a new class of heterogeneous carbo-catalyst was first time reported for synthesis of tert-butyl/ethyl acetate and pyrazole-substituted tetrazole through one-pot 4-C reaction. The synthesized GO-SO3H catalyst offered more than 95% yields of tetrazoles with a broad range of substrates including different substituted aldehyde, isocyanide, and amine within 15–20 min under mild reaction conditions. In addition, sulfonic acid decorated graphene oxide (GO-SO3H) was reused up to five reaction cycles without considerable drop in its catalytic efficiency. The formation of all synthesized pyrazole containing substituted tetrazole derivatives was confirmed by various spectroscopic techniques. [ABSTRACT FROM AUTHOR]

In this study, three types of sulfonic acid group functionalized ionic liquids (SAILs) with a different number of catalytic groups and lipophilicity were synthesized and characterized by FT-IR, NMR, and MS analyses. Their catalytic activities were studied in a model esterification of oleic acid with ethanol; heating in a microwave reactor was also used. The experimental results indicated that SAIL, with the lipophilic alkyl chain, performed the best due to its increased solubility in the reaction mixture. Microwave heating was found to be more effective than conventional heating. Recycling experiments show that these novel SAILs can be reused without significant loss of the catalytic activity. [ABSTRACT FROM AUTHOR]

The sustainable process and direct synthesis of 5-hydroxymethylfurfural (5-HMF), a valuable renewable biofuel and biochemical, was systematically studied using inexpensive catalysts and recyclable magnetic nanocatalysts. Fe 3 O 4 @SBA-16-SO 3 H was obtained by the synthesis of SBA-16 and was modified by MPTES and H 2 O 2. After that, Fe 3 O 4 was synthesized via chemical precipitation and mixed with SBA-16-SO 3 H for easy separation and recovery (using five cycles of catalysts with excellent yield for the synthesis of 5-HMF) and a new magnetic heterogeneous catalyst for the synthesis of 5-HMF that was found to have 95% glucose and fructose conversion and 97% yield of 5-HMF, respectively. The prepared catalyst was characterized by FT-IR, EDAX, XRD, FE-SEM, TEM, VSM, BET, and TGA techniques. The experiments were carried out with good yields and implied that the catalytic method was effective, convenient, and promising for the synthesis of 5-HMF. The present study opens a new avenue for the renewable one-pot synthesis of 5-HMF, a precious product. The efficient conversion of biomass into value-added compounds under mild and safer conditions is a cornerstone of our current research efforts to meet the needs of the chemical industry with sustainable development. [Display omitted] [ABSTRACT FROM AUTHOR]

Sulfonated-silica-coated cobalt ferrite (CoFe2O4) magnetic nanoparticles (MNPs-SiCoFe-SO3H) are efficient heterogeneous catalysts for the synthesis of 3,4-dihydropyrimidin-2(1H)-one and octahydroquinazoline derivatives in the absence of solvent. The effects of solvent, temperature, and catalyst amount on the reaction are investigated. The easy separation, reusability of the catalyst, simplicity of the procedure, mild reaction conditions, and good yields (68–95%) within short reaction times (15–70 min) are the advantages of this method. The catalyst can be reused up to eight times with not much loss of activity. Scanning electron microscopy images, X-ray diffraction spectra, and elemental analysis of the recycled catalyst show that the catalyst is stable after the reaction. [ABSTRACT FROM AUTHOR]

In this work, two catalysts based on polyethylene glycol (PEG) containing sulfonic acid group and the −COOH group of citric acid (CA) were synthesized. Characterization of the −SO3H functionalized PEG and citric acid functionalized PEG has been carried out using FT–IR. The acidity of PEG–SO3H and PEG–CA has been explored to investigate their catalytic efficiency towards eco-friendly production of methyl salicylate via esterification of salicylic acid using methanol as a reactant as well as solvent. Methanol to acid molar ratios of 4:1, 6:1, 8:1, and 10:1 was applied. The sulfonated PEG is found to be a very active solid acid catalyst giving high yields (82%) under the optimized reaction conditions (10:1 M ratio of methanol to acid; reaction temperature, 65 °C; reaction time, 150 min with catalyst loading of 1.5%. In comparison with the catalytic activity of H2SO4, PEG–SO3H, and PEG-CA; the PEG–SO3H surpassed the catalytic activity of both H2SO4 and PEG–CA. The IEC of PEG–SO3H was 4 meq/g. And the maximum water uptake of PEG-SO3H was 8.25%. [ABSTRACT FROM AUTHOR]

As a new alternative to perfluorooctane sulfonic acid (PFOS), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) has been widely produced and used in recent years, and its concentration and frequency of detection in the aquatic environment and aquatic organisms are increasing. However, studies of its toxicity in aquatic biological systems are alarmingly scarce, and the relevant toxicological information needs to be improved. In this study, we investigated AB wild-type zebrafish (Danio rerio) embryos subjected to acute 6:2 FTSA exposure for immunotoxicity using immunoassays and transcriptomics. Immune indexes showed significant decreases in SOD and LZM activities, but no significant change in NO content. Other indexes (TNOS, iNOS, ACP, AKP activities, and MDA, IL-1β, TNF-α, NF-κB, TLR4 content) all showed significant increases. These results indicated that 6:2 FTSA induced oxidative stress and inflammatory responses in zebrafish embryos and exhibited immunotoxicity. Consistently, transcriptomics showed that genes involved in the MAPK, TLR and NOD-like receptor signaling pathways (hsp70, hsp701, stat1b, irf3, cxcl8b, map3k8, il1b, tnfa and nfkb) were significantly upregulated after 6:2 FTSA exposure, suggesting that 6:2 FTSA might induce immunotoxicity in zebrafish embryos through the TLR/NOD-MAPK pathway. The results of this study indicate that the safety of 6:2 FTSA should be examined further. [ABSTRACT FROM AUTHOR]

Sulfonic acid carbon‐(bio)based and natural clays‐based catalysts were prepared and investigated for the first time as heterogeneous catalysts for amide bond synthesis by a Ritter reaction. The different SO3H‐catalysts were screened using benzyl alcohol and acetonitrile as model substrates, and MWCNT‐CSP revealed to be an efficient catalyst, affording the amide in 75 % yield. The practical utility of the catalysts was demonstrated by a diverse range of amides, obtained from alcohols and nitriles, in moderate to good yields. Biomass derived platform alcohols, such as 5‐HMF and furfuryl alcohol, were also tested as potential building blocks for the synthesis of biopolymers. The SO3H‐catalysts revealed to be a highly efficient and environmentally friendly alternative to the conventional acid catalysts commonly used in the Ritter reaction. [ABSTRACT FROM AUTHOR]

Sulfonic acid-functionalized covalent organic frameworks (COF-SO3) as a coating of stir bar sorptive extraction (SBSE) for capturing three fluoroquinolones from milk have been developed. The COF-SO3 material was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. Milk without any typical treatments like protein precipitation and defatting was only diluted five times with water for test. Combined with high-performance liquid chromatography (HPLC), a SBSE-HPLC method was established for detecting fluoroquinolones in milk samples. The corresponding wide linear ranges (4.00–500.0 µg L−1), low detection limits (1.20–2.62 µg L−1), good test repeatability (RSD < 5.2%), and acceptable enrichment factors (56.2–61.5) were implemented for three fluoroquinolones. The analytical method was applied to determine trace targets and provided satisfactory results. Furthermore, the research displayed satisfied reproducibility for bar-to-bar (RSD < 6.5%) and batch-to-batch (RSD < 8.6%) tests. [ABSTRACT FROM AUTHOR]

• UAOD of nC 7 containing tert‑butyl mercaptan, dipropyl sulfide and benzothiophene was studied at 30 bar. • The CCD was utilized to obtain the optimal ultrasonication time for a certain amount of sulfur compounds. • Adsorptive UAOD was investigated for various WHSVs, initial sulfur concentrations and pressures (1 and 30 bar) on breakthrough. • The CCD was applied to study the zeolite-13X regeneration using elution with hot water followed by air drying. The sulfurous compounds in natural gas liquids should be reduced to the extent of satisfying the standard recipes due to corrosion, poisoning of catalysts in downstream processes, reduction in the quality of hydrocarbon products and environmental issues. Ultrasound-assisted oxidative desulfurization is an emerging method for sulfur removal from natural gas liquids. Since natural gas liquids exist in the liquid form of hydrocarbons at high pressures and ambient temperature (25 °C), this work aims to investigate the optimal conditions governing ultrasound-assisted oxidative desulfurization for various sulfurous compounds including mercaptan, sulfide and thiophene at high pressure and finally to appraise the adsorption of oxidized sulfurs and the regeneration of the adsorbent using elution with hot water. So, the effects of sulfur content and ultrasonication time were evaluated at 30 bar. Results showed that as the initial sulfur concentration in normal heptane was increased from 0.00 to 3000 ppmS, the sulfur removal efficiency was enhanced by less than 2 % of 95.9 % and of course, the increased ultrasonication time improved the sulfur removal efficiency. Next, results of the sulfone adsorption using zeolite-13X at 30 bar in continuous mode confirmed that the breakthrough time was reduced from 63 to 12 min as the weight hourly space velocity was increased from 5 to 20 h−1 and pursuantly, the mass transfer zone diminished. Besides, the breakthrough time decreased by 45 - 10 min for increasing the initial sulfur content from 200 to 1000 ppmS. Changing the pressure of the adsorption process from 1 to 30 bar caused the improvement of sulfone adsorption capacity by approximately 3.75 times. In continued, the regeneration of zeolite-13X contaminated with sulfone by flowing hot water was evaluated and the zeolite-13X bed was completely regenerated. [Display omitted] [ABSTRACT FROM AUTHOR]

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO 3 H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Modification of MOF nanochannels with high concentrations of sulfonic acid by introducing polymers into the nanochannels of the MIL-101 series. • The MOF composites exhibited outstanding barium ion adsorption capacity with maximum uptakes of 356.9 mg·g−1. • The MOF composites also exhibited superior proton conductivity with maximum values of 1.43 × 10−1 S·cm−1 at 85 °C and 98 % RH. Porous materials with a high concentration of sulfonic acid groups are highly desirable for applications such as radioactive Ba2+ adsorption, catalysis, and proton-conductive materials, but they are also challenging to synthesize. In this work, we introduce polymers containing sulfonic acid groups into the nanochannels of metal–organic frameworks (MOFs) through in-situ synthesis to enhance the sulfonic acid content. We use a alkene with sulfonic acid groups (2)-acrylamido-2-methylpropane sulfonic acid, AMPS) and a crosslinking agent N,N'-methylenebisacrylamide (MBAA) to synthesize two MOF composites, PAMPS@MIL-101 and PAMPS@MIL-101-SO 3 H, in the ultra-stable MIL-101 series through in-situ polymerization with free radical initiators. The two MOF composites have a high and uniform distribution of sulfonic acid groups in the MOF framework, which results in ultra-high barium ion adsorption capacity. The maximum adsorption amounts are 142.7 and 356.9 mg·g−1 for PAMPS@MIL-101 and PAMPS@MIL-101-SO 3 H, respectively, which are higher than those of most reported adsorbents. Importantly, the adsorption equilibrium can be achieved within 20 min. Moreover, both MOF composites, PAMPS@MIL-101 and PAMPS@MIL-101-SO 3 H, exhibit super proton conductivity, with values of 6.43 × 10−2 S·cm−1 and 1.43 × 10−1 S·cm−1 at 85 °C and 98 % RH, respectively. This method offers a new way of modifying MOF nanochannels with high sulfonic acid concentrations, and opens up new opportunities for developing radioactive Ba2+ adsorption materials and proton-conductive materials. [ABSTRACT FROM AUTHOR]

An extremely productive and sustainable procedure is described for the production of triaryl imidazoles in the presence of graphene oxide-substituted sulfoacetic acid amide as catalyst. Triaryl imidazoles were efficiently synthesized from substituted aromatic aldehydes, benzil, and ammonium acetate via a one-pot procedure using the prepared catalyst under solvent-free conditions. The proposed method showed several advantages over other catalysts, including cost effectiveness, feasibility, green procedure, excellent yields, and short reaction times. The catalyst can be reused for five cycles without significant reduction in its catalytic activity. [ABSTRACT FROM AUTHOR]

The preparation of amorphous and co-amorphous systems (CAMs) effectively addresses the solubility and bioavailability issues of poorly water-soluble chemical entities. However, stress conditions imposed during common pharmaceutical processing (e.g., tableting) may cause the recrystallization of the systems, warranting close stability monitoring throughout production. This work aimed at assessing the water and heat stability of amorphous olanzapine (OLZ) and OLZ-CAMs when subject to wet granulation and pelletization. Starting materials and products were characterized using calorimetry, diffractometry and spectroscopy, and their performance behavior was evaluated by dissolution testing. The results indicated that amorphous OLZ was reconverted back to a crystalline state after exposure to water and heat; conversely, OLZ-CAMs stabilized with saccharin (SAC), a sulfonic acid, did not show any significant loss of the amorphous content, confirming the higher stability of OLZ in the CAM. Besides resistance under the processing conditions of the dosage forms considered, OLZ-CAMs presented a higher solubility and dissolution rate than the respective crystalline counterpart. Furthermore, in situ co-amorphization of OLZ and SAC during granule production with high fractions of water unveils the possibility of reducing production steps and associated costs. [ABSTRACT FROM AUTHOR]

Sulfonate esters are important owing to their special bioactivities. Nevertheless, severe reaction conditions, use of expensive catalysts along with additives and the numerous side reactions in the previously reported methods demand the development of valid approaches for the synthesis of aryl sulfonate esters. Herein, we report a facile synthetic strategy utilizing the VIV based catalyst for the carbene insertion into the O−H bond of sulfonic acids to afford sulfonate esters up to 90 % yield under mild reaction conditions. All the synthesized sulfonate esters were fully characterized by using standard spectroscopic and analytical techniques such as NMR, IR, ESI‐MS and single crystal XRD analysis. [ABSTRACT FROM AUTHOR]

The reaction of hydrazinium sulfate and chlorosulfonic acid in pyridine leads to the pyridinium salt of the hydrazine disulfonate anion, [(SO 3 )HNNH(SO 3 )] 2- . The salt is the starting material for the preparation of further hydrazine disulfonates, for example of alkaline metals and barium. In all compounds, the [(SO 3 )HNNH(SO 3 )] 2- anion adopts the gauche conformation. The conformer is chiral but all of the investigated compounds crystallize as racemates. The disulfonate anion can occur in another constitution with the two sulfonate groups attached to only one nitrogen atom. This so-called hydrazine iso-disulfonate, [H 2 NN(SO 3 ) 2 ] 2- , has been prepared through a substitution reaction between potassium imidodisulfonate, K 2 [HN(SO 3 ) 2 ], and hydroxylamine-O-sulfonic acid, H 2 NOSO 3 H. The hydrazine iso-disulfonate anion has been crystallized as potassium and barium compound, respectively. The compounds were characterized by XRD, vibrational spectroscopy, DFT calculations and thermal analyses., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

In this study, three types of sulfonic acid group functionalized ionic liquids (SAILs) with a different number of catalytic groups and lipophilicity were synthesized and characterized by FT-IR, NMR, and MS analyses. Their catalytic activities were studied in a model esterification of oleic acid with ethanol; heating in a microwave reactor was also used. The experimental results indicated that SAIL, with the lipophilic alkyl chain, performed the best due to its increased solubility in the reaction mixture. Microwave heating was found to be more effective than conventional heating. Recycling experiments show that these novel SAILs can be reused without significant loss of the catalytic activity.

Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock's that are rich in free fatty acids. [ABSTRACT FROM AUTHOR]

Developing a low-cost and effective proton-conductive electrolyte to meet the requirements of the large-scale manufacturing of proton exchange membrane (PEM) fuel cells is of great significance in progressing towards the upcoming "hydrogen economy" society. Herein, utilizing the one-pot acylation polymeric combination of acyl chloride and amine precursors, a polyamide with in-built -SO3H moieties (PA-PhSO3H) was facilely synthesized. Characterization shows that it possesses a porous feature and a high stability at the practical operating conditions of PEM fuel cells. Investigations of electrochemical impedance spectroscopy (EIS) measurements revealed that the fabricated PA-PhSO3H displays a proton conductivity of up to 8.85 × 10−2 S·cm−1 at 353 K under 98% relative humidity (RH), which is more than two orders of magnitude higher than that of its -SO3H-free analogue, PA-Ph (6.30 × 10−4 S·cm−1), under the same conditions. Therefore, matrix-mixed membranes were fabricated by mixing with polyacrylonitrile (PAN) in different ratios, and the EIS analyses revealed that its proton conductivity can reach up to 4.90 × 10−2 S·cm−1 at 353 K and a 98% relative humidity (RH) when the weight ratio of PA-PhSO3H:PAN is 3:1 (labeled as PA-PhSO3H-PAN (3:1)), the value of which is even comparable with those of commercial-available electrolytes being used in PEM fuel cells. Additionally, continuous tests showed that PA-PhSO3H-PAN (3:1) possesses a long-life reusability. This work demonstrates, using the simple acylation reaction with the sulfonated module as precursor, that low-cost and highly effective proton-conductive electrolytes for PEM fuel cells can be facilely achieved. [ABSTRACT FROM AUTHOR]

As a new alternative to perfluorooctane sulfonic acid (PFOS), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) has been widely produced and used in recent years, and its concentration and frequency of detection in the aquatic environment and aquatic organisms are increasing. However, studies of its toxicity in aquatic biological systems are alarmingly scarce, and the relevant toxicological information needs to be improved. In this study, we investigated AB wild-type zebrafish (Danio rerio) embryos subjected to acute 6:2 FTSA exposure for immunotoxicity using immunoassays and transcriptomics. Immune indexes showed significant decreases in SOD and LZM activities, but no significant change in NO content. Other indexes (TNOS, iNOS, ACP, AKP activities, and MDA, IL-1β, TNF-α, NF-κB, TLR4 content) all showed significant increases. These results indicated that 6:2 FTSA induced oxidative stress and inflammatory responses in zebrafish embryos and exhibited immunotoxicity. Consistently, transcriptomics showed that genes involved in the MAPK, TLR and NOD-like receptor signaling pathways (hsp70, hsp701, stat1b, irf3, cxcl8b, map3k8, il1b, tnfa and nfkb) were significantly upregulated after 6:2 FTSA exposure, suggesting that 6:2 FTSA might induce immunotoxicity in zebrafish embryos through the TLR/NOD-MAPK pathway. The results of this study indicate that the safety of 6:2 FTSA should be examined further.

The preparation/application of heterogeneous (nano)materials from natural resources has currently become increasingly fascinating for researchers. Cellulose is the most abundant renewable polysaccharide on earth. The unique physicochemical, structural, biological, and environmental properties of this natural biopolymer have led to its increased application in many fields. The more desirable features of cellulose-based (nano)materials such as biodegradability, renewability, biocompatibility, cost-effectiveness, simplicity of preparation, environmentally friendly nature, and widespread range of applications have converted them into promising compounds in medicine, catalysis, biofuel cells, and water/wastewater treatment processes. Functionalized cellulose-based (nano)materials containing sulfonic acid groups may prove to be one of the most promising sustainable bio(nano)materials of modern times in the field of cellulose science and (nano)technology owing to their intrinsic features, high crystallinity, high specific surface area, abundance, reactivity, and recyclability. In this review, the developments in the application of sulfonated cellulose-based (nano)materials containing sulfonic acid (-SO 3 H) groups in catalysis, water purification, biological/biomedical, environmental, and fuel cell applications have been reported. This review provides an overview of the methods used to chemically modify cellulose and/or cellulose derivatives in different forms, including nanocrystals, hydrogels, films/membranes, and (nano)composites/blends by introducing sulfonate groups on the cellulose backbone, focusing on diverse sulfonating agents utilized and substitution regioselectivity, and highlights their potential applications in different industries for the generation of alternative energies and products. [Display omitted] • This review describes the advantages and necessity of sulfonated cellulose-based materials. • This review provides an overview of the methods used to chemically modify cellulose and its derivatives. • The recent applications of sulfonated cellulose-based materials are comprehensively reviewed. • The mechanism, challenges, and prospects of sulfonated cellulose-based materials are presented. [ABSTRACT FROM AUTHOR]

A new class of sulfonic acid functionalized HY zeolite (HY-N-SA) catalyst has been prepared and characterized by some method such as XRD, FT-IR, FESEM, TEM, TGA, NH3-TPD and N2 physisorption. The result shows the micro-meso structure for catalyst without ordering in the mesophase. Then, the HY-N-SA micro-meso structure was used as an acidic catalyst to synthesize of coumarins via Pechmann reaction and facile transformation of amines to formamides under solvent-free condition. To consider the effect of acidity and kind and size of porous on the catalyst activity, this catalyst was compared with NaY-N-SA and MCM-N-SA and pure porous material (NaY and MCM-41). The significant advantages of HY-N-SA with respect to other catalysts are short reaction times, high yields, pure products, mild conditions and easy work-up. In addition, we report an original and environmentally friendly solvent-free procedure which reusability of catalyst makes this method nearly green and environmentally friendly. [ABSTRACT FROM AUTHOR]

Solid acid catalysts are widely used in the production of various high-value added and industrially important chemicals. Although the use of organosilicon compounds to modify the vacancy site has been extensively studied, the covalent tethering — SO3H functionalized organosilicon modified polyoxometalates (POMs) has been rarely reported. In this work, two catalysts (TBA4[SiW11O39(O(SiC3H6SO3H)2)] (compound 2) and TBA4[SiW11O39 (O(SiC8H8SO3H)2)] (compound 3)) were synthesized successfully through covalently grafting different sulfonic acid (-SO3H) groups onto [SiW11O39]8− cluster, respectively. Compound 2 was achieved by surface grafting and in situ oxidation (3-mercaptopropyl)-trimethoxysilane, while compound 3 was achieved by surface grafting of 2-(4-chlorosulfonylphenyl) ethyltrimethoxysilane. Strong Brønsted acid strength of compounds 2 and 3 can be demonstrated by different methods including potentiometric titration, pyridine adsorption studies, and the 31P trimethylphosphine oxides (TMPO) nuclear magnetic resonance (NMR). The systematic investigation of the relationship among POM structures, acid strength, and electron density was carried out based on density functional theory (DFT) calculation and experimental results, which revealed that covalent modification of compounds 2 and 3 decreased the electron density of the O-H bond, and promoted the release of H+. When applied in hydroxyalkylation/alkylation (HAA) reaction of 2-methylfuran (2-MF) with cyclohexanone, compound 2 exhibited better catalytic performance with conversion of ∼93%, monocyclic fuel precursors (1a) yield of 79.9% and selectivity of 85.7% than compound 3, which can be attributed to strong Brønsted acid and the intramolecular hydrogen-bonding interactions between the neighboring -SO3H moieties in compound 2. Finally, compound 2 also showed excellent catalytic activity in the HAA reaction of 2-MF with several different aldehydes and ketones (e.g., furfuraldehyde, 5-methylfurfuraldehyde, acetone, butyraldehyde and 4-methoxybenzaldehyde). This result opens a new pathway for design and fabrication of novel solid acid catalysts. [ABSTRACT FROM AUTHOR]

The core/shell CaO@SiO2-SO3H nanoparticles were prepared by stabilizing of sulfonic acid on the surface of silica-coated CaO nanoparticles. The structure of CaO@SiO2-SO3H was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX) and thermal gravimetric analysis (TGA). CaO@SiO2-SO3H was used as a new acidic catalyst for green synthesis of dihydropyrano[2,3-c]pyrazoles and tetrahydrobenzo[b]pyrans via one-pot three-component reactions with good to excellent yields. This catalyst could be recycled and reused for six runs without significant loose of activity. [ABSTRACT FROM AUTHOR]

Covalent immobilization of propyl sulfonic acid groups on the surface of magnetic graphene oxide is reported as an efficient magnetically recoverable solid acid catalyst for the conversion of fructose into 5-hydroxymethylfurfural (5-HMF). The obtained nanocomposite has advantages of both graphene oxide (high surface area) and magnetic nanoparticles (fast and facile separation by a magnet). The numerous reaction parameters including solvent, reaction time, temperature, and amount of catalyst were optimized to attain maximum yield of 5-HMF. The results revealed that fructose could be effectively transformed into 5-HMF with a yield of 87% under the optimized reaction conditions. The catalyst could be magnetically separated from the reaction mixture. Moreover, the catalyst exhibited high stability and could be reused for at least five times without a discernible loss of catalytic performance. [Display omitted] • Sulfonic acid groups were immobilized on magnetic graphene oxide nanocomposite. •The nanohybrid was employed as a solid acid catalyst for 5-HMF production. •A maximum 5-HMF yield of 87% was obtained from fructose at 120 °C after 1 h. •The catalyst could be recycled with a little decrease in reactivity. [ABSTRACT FROM AUTHOR]

An enantioselective organocatalytic addition of sodium bisulfite to (E)‐nitroalkenes has been developed by using a chiral bifunctional organocatalyst. The present methodology provides a variety of chiral β‐nitroethanesulfonic acid compounds (17 examples) with excellent results: up to 99 % yield and excellent enantioselectivity (up to 96 % ee). The reaction tolerates (hetero)aryl and alkyl substituents on the β‐nitroalkenes, and β,β‐disubstituted nitroalkenes. [ABSTRACT FROM AUTHOR]

Wide-bandgap NiO nanoparticles (NPs) of 15 nm to 30 nm were synthesized by a facile sol–gel technique in basic medium from the precursor salt followed by calcination at 700°C. As-prepared NPs were used as an inorganic counterpart in the construction of sulfonic-acid-functionalized porphyrin (SAP)-based dye-sensitized solar cells (DSSCs). The procedure involved adsorption of SAP on NiO NPs by thoroughly mixing SAP aqueous solution with a suspension of NiO NPs for 18 h at room temperature. Successful chemisorption of SAP on NiO NPs was confirmed by Fourier-transform infrared, ultraviolet–visible absorption, and fluorescence emission spectroscopy. The fabricated nanohybrid assembly presented incident photon to current conversion efficiency of up to 0.2% for the optimum mixing composition of 30 µL SAP with 0.25 mg/mL NiO NPs in deionized water. The facile and ultrasafe nanofabrication method described herein represents a progressive step towards sustainable DSSC research. [ABSTRACT FROM AUTHOR]

Sulfonic acid groups were employed to improve the adsorption capacity of MCM-41 for cationic dyes removal in the present study. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy assisted with scanning electron microscopy, and nitrogen adsorption–desorption were used to determine the differences between MCM-41 and sulfonic modified MCM-41 (S-MCM-41), and S-MCM-41 still possessed the ordered 2D hexagonal structure. Furthermore, experiments were carried out to explore the adsorption process of methylene blue (MB) on S-MCM-41 and to compare the adsorption capacity of S-MCM-41 with the capacity of MCM-41. The effect of pH values and adsorbent dose on the removal of MB were investigated, and S-MCM-41 can perform better at a pH value of 11 and adsorbent/adsorbate dose of 1.0 g/L. The pseudo-first-order and pseudo-second-order kinetic models were utilized to describe the adsorption process., and it fits better with the pseudo-first-order kinetic model (R² = 0.994). The adsorption isotherm was studied by the Langmuir model (R² = 0.995). Moreover, the regeneration study suggests S-MCM-41 can be easily recovered. S-MCM-41 possesses a high adsorption capacity of 593.22 mg/g while MCM-41 has a fine capacity of 463.23 mg/g, and therefore S-MCM-41 is a promising adsorbent for the removal of cationic dyes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mesoporous activated carbon from sunflower shells was obtained (SAC). • SAC was modified with different amount sulfonic acid groups (SO 3 H). • The acid strength and the number of acid sites increased with the SO 3 H content. • They were tested as catalyst in the esterification of itaconic acid with ethanol. • SACSO3H-20 and SACSO3H-15 catalysts were very active and led to very good yields. Mesoporous activated carbon from sunflower shells (SAC) modified with sulfonic acid groups (SACSO 3 H-XX) was synthesized by grafting the sulfonic groups on the carbon surface to produce novel heterogeneous and reusable solid acid catalysts. The mesoporous carbon was prepared by chemical (H 3 PO 4) and thermal (600 °C) activation of sunflower seed shells. Four materials with increasing SO 3 H content (SACSO 3 H-5, SACSO 3 H-10, SACSO 3 H-15, and SACSO 3 H-20) were obtained using rising chlorosulfonic acid:SAC ratios. They were texturally and physicochemically characterized by SEM-EDX, BET, FT-IR, and TGA-DSC. Potentiometric titration with n-butylamine technique was used to evaluate their acidic properties. The results showed that both the acid strength and the number of acid sites increased with the SO 3 H content in the SACSO 3 H-XX samples. The FT-IR spectra of SACSO 3 H-XX samples confirmed the successful functionalization of SAC with the sulfonic acid group. TGA-DSC diagrams of SACSO 3 H-20 showed that the elimination of the sulfonic groups takes place in the range 250–350 °C. The activity and selectivity of SACSO 3 H-XX in the esterification reaction of itaconic acid with absolute ethanol to form the diester derivative depended strongly on their acidic properties. Furthermore, the effective separation of the product combined with the use of a recyclable catalyst resulted in a clean and environmentally friendly strategy for the synthesis of diethyl itaconate, a bioproduct of relevance to the biorefinery industry. [ABSTRACT FROM AUTHOR]

• Introduction of natural asphalt sulfonic acid as a promising source for carbonaceous compounds. • Functionalization of natural asphalt sulfonic acid with oxalic acid via covalent cross‐linking to make efficient support for copper. • The introduction of heterogeneous NA-SO3H@Oxalic acid-Cu catalysts for the direct synthesis of symmetric N, Nʹ-diaryl guanidines from their corresponding aryl halides with guanidine nitrate. Natural asphalt, containing more than 70 % carbon in molecular structure, is one of the newest and most promising sources for producing large quantities of different carbonaceous compounds. In this article, we report a systematic study of the synthesis of a new network from solid natural asphalt via coating natural asphalt sulfonic acid with oxalic acid. Then, CuI was doped on the NA@oxalic acid network and in fallow that ability as an effective, new, thermal and air-stable, heterogeneous, and reusable catalyst for C N bond formations via cross-coupling reactions of guanidine nitrate with aryl halides was investigated. The shape and size of the heterogeneous NA-SO 3 H@Oxalic Acid-Cu were characterized by SEM, FT-IR, BET,EDX and TGA techniques. In addition, the ability of NA-SO 3 H@oxalic acid@CuI to catalyze cross-coupling reactions was compared to MOF-199. NA-SO 3 H@oxalic acid@Cu, as well as MOF-199, catalyzed coupling reaction of guanidine and aryl halides in short reaction times, high yields, and mild conditions. [Display omitted] [ABSTRACT FROM AUTHOR]