Phosphoric Acid Research Articles

Polymeric ionic liquids and piperidinium synergistically improve proton conductivity and acid retention of polybenzimidazole-based proton exchange membranes

Amino-type polybenzimidazole is prepared, then ionic liquid with three nitrogen positive sites ([CTDTr]Br3) is polymerized into polymeric ionic liquids (PILs) by in-situ radical polymerization, and AmPBI-CTDTr-Px membranes were prepared by piperidinium (PPd) and [CTDTr]Br3 combination to cross-linked with AmPBI. Following treatment with KOH and phosphoric acid (PA), the ion pairs (N+ - H2PO4-) generated in the composite membrane system can enhance proton conductivity and facilitate proton transport. The AmPBI-CTDTr-Px membranes shown exceptional PA retention as a result of the alkaline properties of both [CTDTr]Br3 and PPd, which can engage in acid-base interactions with phosphoric acid. Specifically, the proton conductivity of AmPBI-CTDTr-P5 at 180 °C is 129.7 mS cm-1, which is 2.52 times that of pure membranes. Acid retention of AmPBI-CTDTr-P5 at 80 °C/40% RH and 160 °C are 64.4% and 84%.

Phosphate's second life: Upcycling phosphogypsum and clay by-product through acid geopolymer technology

The present study explores the repurposing of large amounts of phosphoric acid by-products, specifically phosphogypsum (PG), by evaluating its effectiveness as a precursor in acid-activated geopolymer technology. Geopolymers were elaborated using PG and calcined clays, activated with phosphoric acid. The research focused on evaluating the mechanical properties and microstructure of these geopolymers after a 28-day curing period. X-ray diffraction (XRD) analysis revealed the formation of new crystalline phases, including brushite, newberite, and berlinite. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of P-O and Si-O-Al bonds, indicative of successful geopolymerization. Scanning electron microscopy (SEM) imaging demonstrated a dense, cohesive microstructure in optimized samples. Based on the response surface methodology, the study identified optimal conditions for maximum compressive strength: 28.83% PG content, 14.39mol/L phosphoric acid concentration, and a curing temperature of 72.45°C. This optimized formulation produced a dense, cohesive microstructure with a notable compressive strength of 21.46MPa. The leaching test confirmed that no harmful substances were released from the geopolymer samples. These results suggest that PG can be effectively recycled through geopolymer technology for use in the construction industry.

A Novel Nano-Hydroxyapatite Agarose-Based Hydrogel for Biomimetic Remineralization of Demineralized Human Enamel: An in-vitro Study.

This study aims to investigate the biomimetic effect of agarose hydrogel loaded with enamel matrix derivative (EMD-agarose) alone or in combination with nano-hydroxyapatite (n-HA-EMD-agarose) on the remineralization of human demineralized enamel. Extracted human mandibular third molars were sectioned into 54 buccal and lingual halves. Acid-resistant nail varnish was applied to each half, except for two enamel windows. Enamel surface microhardness, energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) analyses were conducted to evaluate enamel surfaces at baseline, following demineralization with 37% phosphoric acid, and after each hydrogel application and remineralization for two, four, and six days. Remineralization was performed using a phosphate solution at 37°C. At day 6 following remineralization, a statistically significant higher mean microhardness was recorded in n-HA-EMD-agarose hydrogel (260.87 ± 3.52) as compared to EMD-agarose hydrogel (244.63 ± 2.76) (p = 0.027). Similarly, n-HA-EMD-agarose hydrogel showed a higher mean calcium (46.31 ± 2.78), phosphorous (24.92 ± 0.826), and fluoride (0.909 ± 0.053) weight percentage compared to EMD-agarose hydrogel calcium (19.64 ± 1.092), phosphorous (19.64 ± 1.092), and fluoride (0.7033 ± 0.0624) weight percentage (p < 0.05). Further, SEM analysis revealed a substantial deposition of n-HA following the application of the n-HA-EMD-agarose hydrogel, whereas the EMD-agarose exhibited a relatively smooth enamel surface with less visible enamel rods due to mineral deposition. The combined n-HA-EMD-agarose hydrogel demonstrated improved surface microhardness of the remineralized enamel and enhanced mineral content deposition, indicating its potential as a biomimetic approach for dental enamel repair.

Investigation of Ceria based Heterostructure Composite Mixed Matrix Membrane with Polybenzimidazole for Polymer Electrolyte Fuel Cell Application at High Temperature

In recent years Ceria based heterostructure composites are considered as one of the highest performing solid state ionic conductors, therefore we wanted to leverage the benefits of using these materials for high temperature Proton Exchange Membrane Fuel Cells (PEMFCs). In this study a Polybenzimidazole (PBI)/Ceria carbonate CHC (Ceria based heterostructure composite) membrane was prepared by drop casting method and tested as an electrolyte for a high temperature H2/Air PEMFC application in anhydrous condition. Inorganic composite of ceria and alkali metal carbonates (Li2CO3, Na2CO3) was prepared by solid state route to obtain Ceria carbonate CHC. X-Ray diffraction (XRD) study confirmed the formation of the heterostructure and their successful incorporation into the PBI membranes. Homogeneity of fillers inside the membrane was further verified by Energy Dispersive X-Ray Analysis (EDAX) and Scanning Electron Microscopy (SEM). 5wt% of inorganic powder induced inside the PBI fillers reduced the phosphoric acid uptake of composite membrane (∼17% less) compared to pristine PBI membrane, which ultimately resulted into a lower swelling and dimensional change of the composite membrane. Thermal robustness of the phosphoric acid doped composite and pristine PBI membranes was investigated by thermogravimetric analysis (TGA) which showed that the prepared membranes were gone under a less than 10% reduction in weight up till 200ºC, ensuring their validity of application in high temp PEM fuel cells. The added inorganic functionalities resulted in a slight increase in the proton conductivity of PA doped composite PBI membranes i.e., 42.3 mS cm-1 at 180 ºC while for pristine PBI membrane it is 36 mS cm-1 at same temperature. A single cell with composite PBI membranes outperformed a pristine PBI membrane resulted into a ∼120% higher peak power density i.e., 320.88 mW cm-2. The composite membrane also displayed the excellent durability and showed a less than 10-4 mV/h degradation in cell potential till 180 ºC.

Preparation of high temperature proton exchange membrane through covalent organic framework doped polyvinylidene fluoride nanofibers

Covalent organic framework (COF) exhibits the great potential to promote proton conduction under low relative humidity for proton exchange membranes (PEMs). In this research, quick and stable proton conduction has been achieved since the prepared COF and polyvinylidene fluoride (PVDF) nanofibers are believed to constitute successive proton conduction channels. The PVDF-COF nanofibers membrane is prepared through the in-situ growth of COF along PVDF nanofibers. The fine compatibility can drive the stable combination of COF with the PVDF nanofibers in PVDF-COF nanofibers. Most importantly, the fibrous PVDF nanofibers accelerate proton conduction through confining the proton conduction pathways. Additionally, ionic liquids of 1-butyl-3-methylimidazolium chloride (BmimCl) and 1-butyl-3-methylimidazole hexafluorophosphate (BmimPF6) as proton conduction carriers have been introduced to accelerate proton conduction in the prepared PVDF-COF/BmimCl/PA and PVDF-COF/BmimPF6/PA membranes. Phosphoric acid (PA) molecules are combined by COF and ionic liquid cations with the formation of intermolecular hydrogen bonds. As a result, the PVDF-COF/BmimPF6/PA membrane exhibits the proton conductivity of (1.81 ± 0.07) × 10−1 S/cm at 160 °C. The long-term proton conductivity stability is determined, deriving from the proton conductivities of 1.77×10−2 S/cm at 80 °C and 1.42×10−2 S/cm at 110 °C in the 400 h non-stop measurement. The single fuel cell equipped with the PVDF-COF/BmimPF6/PA membrane represents the open circuit voltage of 0.927 V and the peak power density of 178.8 mW/cm2 at 100 °C, 0.907 V and 326.5 mW/cm2 at 120 °C.

Extraction of diclofenac and tetracycline from simulated aqueous wastewater using ionic liquids as carriers by pseudo-emulsion hollow fiber strip dispersion

Diclofenac (DCF) and Tetracycline (TC) are used as non-steroidal anti-inflammatory drugs (NSAID) and antibiotics, respectively. Both these drugs, when released into the environment through various routes, cause adverse effects on aquatic life and humans. The traditional approaches employed for the removal of these drugs have various drawbacks and adverse effects on the environment. The present work gives a deeper insight into the potential application of ionic liquids as carriers in the pseudo-emulsion hollow fiber strip dispersion (PEHFSD) technique for removing these compounds from the simulated aqueous solution. The extraction of DCF and TC was performed using different organic carriers, Di-(2-ethylhexyl)phosphoric acid (D2EHPA), Tributyl phosphate (TBP), Trioctyl amine (TOA), and also using ionic liquids, 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide ([EMIM][[TFSI]), 1-Butyl-1-methylpyrrolidinium Bis(trifluoromethanesulfonyl)imide ([BMPy][[TFSI]) and 1-Octyl-3-methylimidazolium Hexafluorophosphate ([OMIM][PF6]). Comparing the performance of all carriers, it was found that [OMIM][PF6] showed 100 % extraction of DCF, while for TC, the maximum extraction obtained was 91.85 %. Effective extraction of DCF and TC up to the 4th cycle indicated the stability of the membrane phase inside the micropore. Membrane phase and pseudo-emulsion are also characterized by FTIR, micrograph images and Turbiscan. A recyclability study of pseudo-emulsion showed that with the increase in the number of cycles for extraction, the stripping phase was gradually saturated by extracting feed (DCF/TC), which led to a drop in extraction efficiency.

Proton direct transport channels incorporated with protonated porphyrin hyper-crosslinked structures for high proton conductivity HT-PEMs

The trade-off between the mechanical properties and proton conductivity of phosphoric acid (PA)-doped polybenzimidazole (PBI) membranes presents a significant challenge to their development and practical application as high-temperature proton exchange membranes (HT-PEMs). In this study, we prepared hyper-crosslinked poly[2,2′-(p-oxydiphenylene)-5,5′-benzimidazole] (OPBI) membranes with porphyrins (TBPP) containing a substantial amount of halogen. The combination of the protonation effect of porphyrin and the support of the hyper-crosslinked structure results in TBPP-OPBI crosslinked membranes exhibiting excellent mechanical strength and proton conductivity at high PA doping levels (ADLs). In particular, the TBPP-15-OPBI crosslinked membrane exhibits high proton conductivity of 244 mS cm−1 at 180 °C, which is 3.64 times greater than that observed in the OPBI membrane. The H2/air fuel cells based on the TBPP-15-OPBI crosslinked membranes exhibit a peak power density of 521.1 mW cm−2 at 160 °C without humidification and back pressure, as well as excellent durability (over 100 h). Thus, this work provides a straightforward and feasible structural design approach to comprehensively enhance the performance of PA-PBI proton exchange membranes.

Can hydrogen be generated by UV- photodegradation of biomass residues in water media?

The photoinduced processes can be promising routes for hydrogen generation. This study explores hydrogen production through the non-catalyzed photodegradation of various biomass materials, a process that remains largely understudied compared to the catalyzed ones, i.e., photoreforming. Using as precursor almond shell (AS), a lignocellulosic biomass residue, various solid and liquid materials obtained from it were tested as substrates. These materials were obtained through different pretreatment methods including grinding, milling, pyrolysis, and hydrothermal carbonization (HTC), and compared with milled cellulose (MC). Photodegradation tests, conducted in aqueous media under UV light, revealed that hydrogen production strongly depends on the structural and compositional features of the substrates. Among the solid samples, ground almond shell (GAS) and milled cellulose (MC) showed promising hydrogen yields. However, the liquid residue from the HTC process using diluted phosphoric acid (HMAS-L2), which is rich in simple organic acids, stood out, delivering the highest hydrogen production across all the substrates, and reaching an impressive value of 105 μmol of H2 in 5 h of reaction. Attention was also given to the production of other gases, particularly carbon dioxide and methane, as a result of the photodegradation. CO2 production occurred for all the substrates. PMAS (the pyrolyzed milled almond shell) and, specifically, HMAS-L2 generated detectable amounts of CH4 (5 and 22 μmol, respectively).The H2/CO2 ratios reached 0.66 for MC and 0.44 for HMAS-L2, highlighting the interest in evaluating the non-catalyzed biomass photodegradation as a preliminary step for future photoreforming studies. These findings enhance our understanding of biomass-based hydrogen generation and open new avenues for exploring non-catalyzed photoinduced processes.

Assessment of Cerium Adsorption Potential of Phosphoric acid Activated Biochar in Aqueous System: Modelling and Mechanistic Insights

Cerium pollution in waterbodies by improper industrial waste disposal is a major concern due to its detrimental impacts on the environment. Therefore, treatment of cerium-contaminated water is inevitable. Hence, this study is focused on the remediation of cerium pollution using phosphoric acid-activated biochar (PPMB) as an adsorbent, synthesized upon pyrolytic activation of palmyra palm male flower-based pristine biochar (PMFB) with H3PO4 at 500°C. The physico-chemical surface properties of PMFB and PPMB were evaluated through various microscopic and spectroscopic analyses. The key parameters such as biochar dosage, pH, temperature, contact time and initial cerium concentration were optimized as 0.5 g/L, 5.0, 303 K, 180 min and 50 mg/L respectively via batch adsorption. Pseudo-second order kinetic and Toth isotherm are the best-fitted models. The thermodynamic parameters including ΔG◦ (-30.4707±0.7618 kJ/mol at 303 K), ΔH◦ (16.1499±0.78 kJ/mol), and ΔS◦ (153.617±3.8404 J/mol/K) conveying that cerium adsorption onto PPMB was spontaneous, endothermic, and highly disordered at PPMB-bulk adsorption medium interface. Precipitation, electrostatic attraction, and surface complexation are predicted to be the predominant mechanisms for the chosen PPMB-cerium adsorption system. Moreover, cerium phytotoxicity on Vigna radiata explains the real-time applicability and feasibility of cerium adsorption using PPMB. Thus, the key findings of this study specified that the higher adsorption capacity of PPMB (141.3484±6.9856 mg/g) contributed by the incorporated phosphate groups, predominant mesoporosity, SSABET of 230.559 m2/g and anionic surface at a wider pH range (pH>3.08) make PPMB as efficient, economically feasible and environmentally friendly adsorbent for cerium adsorption in aqueous system.

Application and thermodynamic analysis of iron and chromium fractional recovery and phosphoric acid regeneration from iron phosphate pre-solution

Chromium and phosphate both are significant contaminants in water resources. This study investigates their separate removal and recovery from pre-solution through a stepwise precipitation and regeneration process. A comprehensive thermodynamic analysis revealed that the process could be optimized by controlling pH values, with the optimal operational window predicted by constructing lgc-pH diagrams of the Fe3+-Cr3+-Al3+-Mg2+-Ca2+-H3PO4-H2C2O4 system. Calcium carbonate was used as the precipitant, while sulfuric acid served to regenerate phosphoric acid. The results revealed that the precipitation of Fe3+ was predominant at pH ∼ 2.5, whereas chromium enrichment occurred at pH ∼ 3.5. Additionally, treating the post-precipitation solution with sulfuric acid not only recycled phosphate but also removed residual Ca2+ from the liquid. The precipitation efficiency of chromium exceeded 90 %, reducing the residual soluble chromium content to 54 mg/L. Eventually, the continuous experiment for the actual pre-solution revealed that chromium was enriched in the calcium phosphate residue, and phosphate was successfully regenerated at a solution pH of ∼ 0.6. This environmentally friendly and sustainable process efficiently recovers chromium while regenerating phosphoric acid, highlighting its potential for practical applications.

Utilization of waste phosphogypsum in high-strength geopolymer concrete: Performance optimization and mechanistic exploration

Phosphogypsum (PG) is an industrial waste produced during the manufacture of phosphoric acid. In this study, dihydrate phosphogypsum (DPG), ground granulated blast furnace slag (GGBFS), fly ash (FA), Portland cement clinker (PCC), sulfate alumina cement clinker (SACC), water reducer, sand, and stone were combined to create a phosphogypsum-based geopolymer (PBG) concrete. Concrete mix design was carried out based on the principle of maximum packing density, and the effects of water reducer type, sand ratio, water-to-binder ratio, and DPG content on PBG concrete properties were investigated. Results indicated that compared to SiKa ViscoCrete 540P (SVC 540P) water reducer, Melflux PLUS 1087L (MP1087L) significantly enhanced the performance of PBG concrete. With a water-to-binder ratio of 0.34, a sand ratio of 32.2 %, and a PG:GGBFS:FA ratio of 5:4:1, the 28-day unconfined compressive strength (UCS) of the concrete exceeded 60 MPa. The concrete primarily consisted of phases such as dihydrate gypsum (CaSO4·2H2O), ettringite (Ca6(Al(OH)6)2(SO4)3(H2O)26), polymer (-Si-O-Al-), quartz (SiO2), albite (Na(AlSi3O8)) and Muscovite ((K,Na)Al2(Si,Al)4O10(OH)2). Using two mild alkalis as activators, PBG concrete can avoid the efflorescence often associated with geopolymer preparation and can cure at 20 °C. PBG concrete offers high strength, ease of preparation, and environmental benefits, providing a new avenue for the reuse of PG.

Thermodynamic, Economic and Regulation Strategies Analysis of a Phosphoric Acid Fuel Cell Combined Heating and Cooling

Thermodynamic, Economic and Regulation Strategies Analysis of a Phosphoric Acid Fuel Cell Combined Heating and Cooling

Organocatalytic Asymmetric Cascade Bicyclization of 2‐Indolylmethanols with α‐(2‐Indolyl) Propargylic Alcohols to Access Chiral Fluorescent Hexacyclic Bisindoles

AbstractA cascade regioselective 1,8‐addition/biscyclization of 2‐indolylmethanols with α‐(2‐indolyl) propargylic alcohols has been developed via chiral phosphoric acid (CPA) catalysis. A series of chiral cyclopenta[4,5]pyrrolo biindoles bearing a quaternary stereogenic center were obtained in modest to good yields (72–95%) with high enantioselectivities (82–94%). Additionally, the photophysical properties of these hexacyclic bisindoles are examined, revealing bright fluorescence with high quantum yields.

Quality by Design Approach Driven Development and Validation of Reverse Phase‐High‐Performance Liquid Chromatography Methodology for Dual Quantification of Aspirin and Rivaroxaban

ABSTRACTClinical trials have shown that combining a modest dose of Rivaroxaban (RIV) with Aspirin (ASP) is more effective than ASP alone in reducing cardiovascular mortality, myocardial infarction, and stroke. A high‐performance liquid chromatography method developed using Quality by Design (QbD) effectively estimates ASP and RIV for routine pharmaceutical analysis. The Plackett‐Burman design assessed key factors including organic phase volume, mobile phase pH, flow rate, temperature, and injection volume using an Ishikawa fish‐bone diagram for risk assessment. These parameters were then optimized via Box‐Behnken design in 15 trials. The method meets the International Council For Harmonization standards with a mobile phase ratio of 45:55 (v/v) acetonitrile: buffer (pH 3, adjusted with orthophosphoric acid), a flow rate of 1 mL/min, a column temperature of 30°C, and an injection volume of 20 µL. A Phenomenex Luna C18 column (250 × 4.6 mm, 5 µm particle size) with detection at 251 nm ultra‐violet wavelength. The retention times of 4.54 min for ASP and 5.81 min for RIV were obtained. Validation confirmed linear ranges: 40–200 µg/mL for ASP and 2–10 µg/mL for RIV, with excellent recovery rates (ASP: 99.30%–101.9%; RIV: 98.52%–101.84%). Developed using QbD principles, the method proved specific, accurate, precise, sensitive, and robust for routine quality control of both compounds in pharmaceutical formulations.

Identification of Fusarium Wilt Disease Causal Agents in Pistachio Fields and Determination of Efficacy of Some Fungicides Controlling of The Disease

Pistachio (Pistacia vera) propagation is commonly carried out by seedlings and new orchards are mostly set by in situ grafting of rootstocks. Pathogenic and molecular characterization of wilt and desiccation agents observed in nurseries and young orchards were carried out and the causal species were identified as Fusarium oxysporum and F. solani. In vitro inhibition of mycelial development and conidia germination were carried out with seven fungicides selected against the disease. The plant protection product containing Prothioconazole + Spiroxamine was found to be 100% effective in mycelial growth trials in F. oxysporum isolates from 20 mgL-1 and in F. solani from 100 mL-1 at all increasing doses. . The fungicide containing phosphoric acid was found to be 18.3%-33.3% effective on both species at 2.5 times the recommended dose. On conidial germination, Prothioconazole + Spiroxamine and Captan provided 100% inhibition even at the lowest doses in all isolates tested. The EC50 values of Prothioconazole + Spiroxamine, which was determined as the most effective chemical in mycelial development and conidial germination, were 3.67 ml and 3.72 ml in F. oxysporum isolates and 56.83 ml in F. solani, respectively.

Highly Conducting and Ultra-Stretchable Wearable Ionic Liquid-Free Transducer for Wireless Monitoring of Physical Motions.

Wearable strain transducers are poised to transform the field of healthcare owing to the promise of personalized devices capable of real-time collection of human physiological health indicators. For instance, monitoring patients' progress following injury and/or surgery during physiotherapy is crucial but rarely performed outside clinics. Herein, multifunctional liquid-free ionic elastomers are designed through the volume effect and the formation of dynamic hydrogen bond networks between polyvinyl alcohol (PVA) and weak acids (phosphoric acid, phytic acid, formic acid, citric acid). An ultra-stretchable (4600% strain), highly conducting (10 mScm-1), self-repairable (77% of initial strain), and adhesive ionic elastomer is obtained at high loadings of phytic acid (4:1 weight to PVA). Moreover, the elastomer displayed durable performances, with intact mechanical properties after a year of storage. The elastomer is used as a transducer to monitor human motions in a device comprising an ESP32-based development board. The device detected walking and/or running biomechanics and communicated motion-sensing data (i.e., amplitude, frequency) wirelessly. The reported technology can also be applied to other body parts to monitor recovery after injury and/or surgery and inform practitioners of motion biomechanics remotely and in real time to increase convalescence effectiveness, reduce clinic appointments, and prevent injuries.

Novel Aryl Phosphate for Improving Fire Safety and Mechanical Properties of Epoxy Resins.

Epoxy resins (EPs) are highly flammable, and traditional flame retardant modifications often lead to a significant reduction in their mechanical performance, limiting their applications in aerospace and electrical and electronic fields. In this study, a novel flame retardant, bis(4-(((diphenylphosphoryl)oxy)methyl)phenyl)phenyl phosphate (DMP), was successfully prepared and introduced into the EP matrix. When the addition of DMP was 9 wt%, the EP/9 wt% DMP thermosets passed the UL-94 V-0 rating, and their LOI was increased from 24.5% of EP to 35.0%. With the introduction of DMP, the phosphoric acid compounds from the decomposition of DMP promoted the dehydration and charring of the EP matrix, and the compact, dense char layer effectively exerted the shielding effect in the condensed phase. Meanwhile, the produced phosphorus-containing radicals played a quenching effect in the gas phase. As a result, the peak heat release rate (PHRR) and total heat release (THR) of EP/9 wt% DMP were reduced by 68.9% and 18.1% compared to pure EP. In addition, the polyaromatic structure of DMP had good compatibility with the EP matrix, and the tensile strength, flexural strength and impact strength of EP/9 wt% DMP were enhanced by 116.38%, 17.84% and 59.11% in comparison with that of pure EP. This study is valuable for expanding the application of flame-retardant EP/DMP thermosets in emerging fields.

Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions.

Regeneration of a Fire‐Resistant Fluid‐Fouled Strong Base Anion Resin using a Caustic Solution with Citric Acid as a Surfactant

AbstractFire Resistant Fluid (FRF), used in turbine governing systems, transforms during operation, forming substituted phenol and phosphoric acid. The use of strong Base Anion Resin (SBA resin) to reduce the Total Acid Number (TAN) of FRF is widespread. However, the regeneration of these oil‐fouled resins is crucial due to their high cost and the challenges associated with their environmental disposal. In this study, we present a novel method for recovering exhausted resin by treating it with an aqueous solution of citric acid, followed by regeneration with a caustic soda solution. We optimized the recovery percentage in the ion exchange capacity by testing varying concentrations of the citric acid solution under different reaction conditions. The highest recovery of ion exchange capacity achieved was 55 % after soaking for 16 hours in a 5 % citric acid solution, followed by regeneration with a 5 % NaOH solution. The efficacy of citric acid in this research was further explored through a Density Functional Theory (DFT) study. This study is significant as it is the first to demonstrate the successful regeneration of oil‐fouled resins with high ion exchange capacity using citric acid, a more environmentally friendly and cost‐effective alternative.

Synthesis of Chiral Axially Diaryl Aldehydes by Chiral Phosphoric Acid Catalyzed Desymmetrization Reaction

Axially chiral biaryl aldehydes are precursors for the synthesis of axially chiral compounds and novel chiral catalysts of great interest, which play vital roles in extensive research fields. However, limited strategies exist for the efficient synthesis of axially chiral aldehydes, and the construction of structurally diverse axially chiral aldehydes remains challenging. Herein, a strategy is reported for the synthesis of biaryl axially chiral aldehydes with varying structures from biaryl dialdehydes and aromatic amines in the presence of a chiral phosphoric acid catalyst. This protocol features excellent enantioselectivity, mild conditions, and good functional‐group tolerance.