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Porous mullite ceramics were synthesized via ceramic processing using a local industrial kaolin, alumina, and with AlF3 and MoO3 precursor additives to catalyze the formation of pores and acicular mullite grains. The textural properties, crystalline phases, microstructures, and mechanical properties of the obtained samples were comprehensively analyzed and compared with a reference mullite formulated without additives. The obtained ceramics have a well‐defined porous microstructure, with a porosity of about 50%, and a pore size distribution in the 0.1–2 µm range. Ceramics that involve the addition of MoO3 present well‐defined acicular mullite grains, with slightly higher porosity, larger pores, and better mechanical resistance compared to those processed using AlF3.To correlate the ceramic porosity with its mechanical properties, a simple model of spherical pores was proposed to assess the flexural strength of the dense ceramic. It was found that the inclusion of additives promoting needle‐like microstructures increases the mechanical resistance up to four times the value determined for the ceramic without additives (flexural strength up to 390 MPa for zero‐porosity extrapolation). These results, together with the refractoriness of mullite, allow inferring the potential applications of the developed materials as structural ceramics with relatively low density and for filtering applications. [ABSTRACT FROM AUTHOR]

The Protein Data Bank (PDB) was scrutinized for the presence of noncovalent O ⋅ ⋅ ⋅ Al Triel Bonding (TrB) interactions, involving protein residues (e. g. GLU and GLN), adenosine/guanine diphosphate moieties (ADP and GDP), water molecules and two aluminum fluorides (AlF3 and AlF4−). The results were statistically analyzed, revealing a vast number of O ⋅ ⋅ ⋅ Al contacts in the active sites of phosphoryl transfer enzymes, with a marked directionality towards the Al σ‐/π‐hole. The physical nature of the TrBs studied herein was analyzed using Molecular Electrostatic Potential (MEP) maps, the Quantum Theory of Atoms in Molecules (QTAIM), the Non Covalent Interaction plot (NCIplot) visual index and Natural Bonding Orbital (NBO) studies. As far as our knowledge extends, it is the first time that O ⋅ ⋅ ⋅ Al TrBs are analyzed within a biological context, participating in protein trapping mechanisms related to phosphoryl transfer enzymes. Moreover, since they are involved in the stabilization of aluminum fluorides inside the protein's active site, we believe the results reported herein will be valuable for those scientists working in supramolecular chemistry, catalysis and rational drug design. [ABSTRACT FROM AUTHOR]

The P-loop fold nucleoside triphosphate (NTP) hydrolases (also known as Walker NTPases) function as ATPases, GTPases, and ATP synthases, are often of medical importance, and represent one of the largest and evolutionarily oldest families of enzymes. There is still no consensus on their catalytic mechanism. To clarify this, we performed the first comparative structural analysis of more than 3100 structures of P-loop NTPases that contain bound substrate Mg-NTPs or their analogues. We proceeded on the assumption that structural features common to these P-loop NTPases may be essential for catalysis. Our results are presented in two articles. Here, in the first, we consider the structural elements that stimulate hydrolysis. Upon interaction of P-loop NTPases with their cognate activating partners (RNA/DNA/protein domains), specific stimulatory moieties, usually Arg or Lys residues, are inserted into the catalytic site and initiate the cleavage of gamma phosphate. By analyzing a plethora of structures, we found that the only shared feature was the mechanistic interaction of stimulators with the oxygen atoms of gamma-phosphate group, capable of causing its rotation. One of the oxygen atoms of gamma phosphate coordinates the cofactor Mg ion. The rotation must pull this oxygen atom away from the Mg ion. This rearrangement should affect the properties of the other Mg ligands and may initiate hydrolysis according to the mechanism elaborated in the second article. [ABSTRACT FROM AUTHOR]

Reasonable mathematical derivation and mechanism model in the process of producing aluminum fluoride by fluosilicic acid is the key to the industrial treatment of fluorine resources in the tail gas of phosphate ore. In this work, aluminum fluoride was generated directly by fluosilicic acid to extract fluorine from the tail gas of phosphate rock. The uncreated-core model dominated by interfacial reaction and the uncreated-core model dominated by internal diffusion-reaction were then respectively utilized to describe the reaction kinetics of the generation of aluminum fluoride. The result showed that the uncreated-core model was dominated by interface reaction and internal diffusion, the apparent reaction order n = 1, and the activation energy Ea = 30.8632 kJ · mol–1. Product characterization and kinetic analysis were employed to deduce the reaction mechanism of preparing aluminum fluoride. The theoretical basis for the low-cost recycling of fluorine resources in the tail gas of industrial phosphate ore was provided in this work.

The hydrofluorocarbon 245 isomers, 1,1,1,3,3-pentafluoropropane, 1,1,1,2,2- pentafluoropropane, and 1,1,1,2,3-pentafluoropropane (HFC-245fa, HFC-245cb, and HFC-245eb) were activated through C–F bond activations using aluminium chlorofluoride (ACF) as a catalyst. The addition of the hydrogen source Et3SiH is necessary for the activation of the secondary and tertiary C–F bonds. Multiple C–F bond activations such as hydrodefluorinations and dehydrofluorinations were observed, followed by hydroarylation and Friedel–Crafts-type reactions under mild conditions.

Lithium-sulfur (Li–S) battery has now gradually emerged as the representative secondary energy storage battery of low cost, high security, and high theoretical specific capacity (1675 mAh g−1). However, the insulation properties of sulfur and shuttle issue of polysulfides between electrolytes lead to poor coulombic efficiency and performance of sulfur cathode. Therefore, we use metal–organic frameworks (MOFs) as pore-forming agent and glucose as primary carbon source to synthesize a honeycomb structured porous carbon (PC) material with high specific surface area (2151.9 m2 g−1) and large mesopore volume (2.16 cm3 g−1), which acts as the conductive skeleton for sulfur cathode. Furthermore, after mixing a trace of aluminum fluoride (AlF3) into sulfur electrode, the corresponding cycle performance and electrochemical stability have been further improved. The AlF3·3H2O/PC/S composition with 80 wt% sulfur loading exhibits the highest discharge capacity of 1298.1 mAh g−1 at the current density of 1 C and maintains at 455.6 mAh g−1 with ~ 99% coulombic efficiency after 500 cycles. This work supplies a facile and effective strategy for manufacture of more progressive porous carbonaceous sulfur host material and improving practical performance of Li–S batteries. [ABSTRACT FROM AUTHOR]

We report herein an efficient and fully automated protocol for the radiosynthesis of [18F]FAPI‐74, a new positron emission tomography (PET) radiopharmaceutical for in vivo detection of the fibroblast activation protein. [18F]FAPI‐74 was synthesized via a rapid [18F]aluminum fluoride coordination reaction, which was first developed on the flexible GE TRACERLab FX2N (FXN) platform and later translated to the cassette‐based module Trasis AllInOne (AIO). The results obtained with both modules were comparable in terms of yield and reproducibility. Automation of [18F]FAPI‐74 radiosynthesis on the FXN was carried out in 35 min with a radiochemical yield (RCY) of 18.5 ± 2.5% (n = 5, relative to starting [18F]fluoride). Method transfer to the AIO platform following minor optimizations allowed for the production of [18F]FAPI‐74 in an isolated RCY of 20 ± 2.5% [n = 3] with an overall synthesis time of 40 min. The radiochemical purity was greater than 95% for [18F]FAPI‐74, obtained from both modules. Overall, the protocol reliably provides a sterile and pyrogen‐free good manufacturing practice (GMP) compliant product of [18F]FAPI‐74 suitable for clinical PET imaging. [ABSTRACT FROM AUTHOR]

Extensive research has focused on developing wide-bandgap metal compound-based passivating contacts as alternatives to conventional doped-silicon-layer-based passivating contacts to mitigate parasitic absorption losses in crystalline silicon (c-Si) solar cells. Herein, thermally-evaporated aluminum halides (AlX)-based electron-selective passivating contacts for c-Si solar cells are investigated. A low contact resistivity of 60.5 and 38.4 mΩ cm 2 is obtained on the AlCl x /n-type c-Si (n-Si) and AlF x /n-Si heterocontacts, respectively, thanks to the low work function of AlX. Power conversion efficiencies (PCEs) of 19.1% and 19.6% are achieved on proof-of-concept n-Si solar cells featuring a full-area AlCl x /Al and AlF x /Al passivating contact, respectively. By further implementing an ultrathin SiO 2 passivation interlayer and a pre-annealing treatment, the electron selectivity (especially the surface passivation) of AlX is significantly enhanced. Accordingly, a remarkable PCE of 21% is achieved on n-Si solar cells featuring a full-area SiO 2 /AlF x /Al rear contact. AlF x -based electron-selective passivating contacts exhibit good thermal stability up to ≈400 °C and better long-term environmental stability. This work demonstrates the potential of AlF x -based electron-selective passivating contact for solar cells., (© 2024 Wiley‐VCH GmbH.)

Human guanylate‐binding protein 1 (hGBP‐1) shows a dimer‐induced acceleration of the GTPase activity yielding GDP as well as GMP. While the head‐to‐head dimerization of the large GTPase (LG) domain is well understood, the role of the rest of the protein, particularly of the GTPase effector domain (GED), in dimerization and GTP hydrolysis is still obscure. In this study, with truncations and point mutations on hGBP‐1 and by means of biochemical and biophysical methods, we demonstrate that the intramolecular communication between the LG domain and the GED (LG:GED) is crucial for protein dimerization and dimer‐stimulated GTP hydrolysis. In the course of GTP binding and γ‐phosphate cleavage, conformational changes within hGBP‐1 are controlled by a chain of amino acids ranging from the region near the nucleotide‐binding pocket to the distant LG:GED interface and lead to the release of the GED from the LG domain. This opening of the structure allows the protein to form GED:GED contacts within the dimer, in addition to the established LG:LG interface. After releasing the cleaved γ‐phosphate, the dimer either dissociates yielding GDP as the final product or it stays dimeric to further cleave the β‐phosphate yielding GMP. The second phosphate cleavage step, that is, the formation of GMP, is even more strongly coupled to structural changes and thus more sensitive to structural restraints imposed by the GED. Altogether, we depict a comprehensive mechanism of GTP hydrolysis catalyzed by hGBP‐1, which provides a detailed molecular understanding of the enzymatic activity connected to large structural rearrangements of the protein. Database: Structural data are available in RCSB Protein Data Bank under the accession numbers: 1F5N, 1DG3, 2B92. [ABSTRACT FROM AUTHOR]

• Propose a new method for preparing AF 3 that the carbon residue as a raw material. • Fluoride weas converted to AF 3 through roasting with anhydrous Al 2 (SO 4) 3. • The roasting leaching method was utilized to obtain 94.30 % purity AF 3. • The overall recovery rate of fluorine throughout the entire process was 94.56 %. The carbon residue is a hazardous waste generated by the aluminum electrolysis production process, which contains a large amount of electrolyte fluoride salts. In order to recover the electrolyte components in carbon residue, this paper proposes a new method of using carbon residue to prepare aluminum fluoride by converting Na 5 Al 3 F 14 and Na 3 AlF 6 in carbon residue into aluminum fluoride to realize the recycling of fluoride in carbon residue. In the initial step, optimal parameters for carbon removal during roasting have been determined, including an oxygen flow rate of 7 g/min, a roasting temperature of 670 °C, and a roasting time of 80 min. The roasted clinker is obtained, and the removal rate of carbon reaches 99.95 % while the loss rate of fluorine is 0.48 %. In the second step, the mix anhydrous Al 2 (SO 4) 3 with roasted clinker for roasting. The optimal roasting temperature of 670 °C, the time of 10 min, and the mass ratio of anhydrous Al 2 (SO 4) 3 to roasted clinker of 5:5 could convert fluoride to AlF 3 products, with a conversion rate of 99.76 % and a loss rate of fluorine of 1.05 %. Finally, by removing sulfate impurities through water leaching for 15 min at 35 °C and with a liquid-solid ratio of 6 ml/g, the loss rate of fluorine is 3.98 %. This process yields AlF 3 with a purity of 94.30 %. The recovery rate of fluorine in the whole process is 94.56 %, which successfully achieves the recycling of fluorine in the carbon residue to obtain AlF 3 products. [Display omitted] [ABSTRACT FROM AUTHOR]

Ni 2 + bearing fluoro-aluminoborate glass composition [( AlF 3) x - (B 2 O 3) 0.63-x - (NiO) 0.2 - (Na 2 O) 0.35 ] was prepared via the melt-quenching method. The structure of glass was confirmed by X-Ray diffraction patterns, density, molar volume and infrared spectroscopy. The oxygen and fluorine bonds with the other constituent cations are the backbone of network. Additionally, the ligand field transitions of nickel ions were assigned for octahedral and tetrahedral forms. Unexpectedly, the addition of fluorine, mixed with oxygen, increased the splitting energy of 3d-orbitals of Ni 2 + ions. This unexpected behavior is back to the influence of the high field intensity of aluminum cations at the expense of boron cations. The splitting energy of 3d-orbitals (10Dq) increased, while inter-electronic repulsion parameters (B and C) decreased. The chemical bonding nature was evaluated. The color variation of samples from dark brown to light brown was explained. Furthermore, the optical band gap decreased owing to the high delocalization of electrons. • The intense to light brown color confirmed the existence of Ni2+ cations. • With increasing the AlF 3 /B 2 O 3 contents, the conversion from BO 4 to BO 3 increased. • An increase in the crystal field splitting and an increase in Racah parameters. • The bonding nature between the Ni cations and their surroundings is more covalent. [ABSTRACT FROM AUTHOR]

The form and concentration distribution of anions in a molten KF-AlF3 system with different molar ratios (1.5–8) at different temperatures were analyzed with Raman spectroscopy. The results indicate that for molar ratios in the range of 1.5–5, AlF63−, AlF52−, AlF4−, and F−, were all present in the system, while for molar ratios in the range of 6–8, only AlF63−, AlF52−, and F−, were present. For molar ratios in the range of 1.5–2.5, the AlF52− ion content was the most sensitive to temperature among all the complex ions in the system, whereas for molar ratios in the range of 4–8, minor variations in the constituent anion contents were observed as a function of temperature. The Al3+ ions in the system with the molar ratios of 1.5–5, 6, and 7 or 8 tended to form AlF4−, AlF52−, and AlF63−, respectively, as the temperature increased. [ABSTRACT FROM AUTHOR]

The current status of cathode materials for lithium‐sulfur (Li−S) battery is not satisfactory for full‐scale commercial production. This mainly stems from the unsolved problems associated with the polysulfide shuttle, which leads to lower sulfur utilization and significant capacity decay after a few hundred cycles. To better confine sulfur and its associated polysulfides, a core/double‐shelled nanocomposite was synthesized. The inner shell was composed of a carbon nanosphere with high conductivity, while the outer shell was an ultra‐thin aluminum fluoride (AlF3) layer to better retain polysulfides in the cathode structure. The AlF3 coating increased the initial discharge capacity to 1191 mA h g−1 with capacity retention of 76.3% and Coulombic efficiency > 99% over 100 cycles. Taking advantage of this tailored design, a reversible capacity of 702 mA h g−1 over 500 cycles at 1 C was achieved with only 0.052% capacity decay per cycle. This impressive electrochemical performance was ascribed to the enhanced conductivity and effective entrapment of polysulfides. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carbon-containing AlF 3 catalysts were prepared using organic aluminum precursors. • Incomplete decomposition of organic precursors resulted in the formation of carbonaceous species. • C-AlF 3 composite catalysts were active and stable for dehydrofluorination of HFC-245fa. • Catalyst deactivation was due to coke deposition on the catalyst surface. • Pre-deposited carbonaceous species in the catalyst blocked strong acid sites of AlF 3. Abstract A series of C-AlF 3 composite catalysts were prepared using a sol-gel method and different aluminum precursors (i.e. aluminum isopropoxide (Al(O i Pr) 3) and aluminum diacetate hydroxide (C 4 H 7 AlO 5)). These catalysts were very active in gas-phase dehydrofluorination of 1, 1, 1, 3, 3-pentafluoropane. For example, a catalyst calcined at 400 °C with aluminum isopropoxide as the precursor (denoted as C-AlF 3 -AIP-400) gave a reaction rate of 8.30 μmol s−1 g cat -1 and a selectivity to 1, 3, 3, 3-tetrafluoropropene (HFO-1234ze) of above 99% at 340 °C. More importantly, the C-AlF 3 catalysts showed excellent stability during 100 h reaction, while the pure AlF 3 catalyst suffered severe deactivation owing to the coke deposition on the surface. In contrast, pre-deposited carbonaceous species formed in the catalyst due to the incomplete decomposition of organic precursors during the preparation procedure, which blocked strong acidic sites in the AlF 3 and thus maintained the catalyst stability. Therefore, these findings provide useful information on the development of efficient catalyst for this reaction, particularly on the maintainance of catalyst stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The main forms of Al-F complex ion groups in Na 3 AlF 6 molten salt are [AlF 4 ]−, [AlF 5 ]2− and [AlF 6 ]3−. • There is covalent interaction between Al-F in molten salt and electrons transfer from Al-3p orbital to F-2p orbital. • Raman spectra of [AlF 4 ]−, [AlF 5 ]2− and [AlF 6 ]3− are calculated at 595 cm−1, 547 cm−1 and 436 cm−1. Abstract First-principles molecular dynamics simulation (FPMD) has been applied to study the ionic structure and electronic properties of Na 3 AlF 6 molten salt. The results show that the main forms of complex ion groups in molten salt are [AlF 4 ]−, [AlF 5 ]2− and [AlF 6 ]3−, with the proportion of 10%, 60% and 30%, respectively. The electron orbitals near Fermi level are mainly occupied by F-2p and hybridize with Al-3p orbitals, in which electrons are transferred from Al-3p orbitals to F-2p orbitals. The calculation results of Raman spectra on [AlF 4 ]−, [AlF 5 ]2− and [AlF 6 ]3− are close to the experimental values, indicating FPMD is applicable to similar molten salt systems. [ABSTRACT FROM AUTHOR]

The preparation of CH3F via vapor phase catalytic fluorination of CH3OCH3 promoted by AlF3 (H‐AlF3, M‐AlF3, L‐AlF3) with different surface areas was investigated, with the reaction occurring as follows: CH3OCH3 +2 HF → 2CH3F + H2O. It was found that H‐AlF3 exhibited the highest catalytic activity with high stability among the three types of AlF3 tested in the 100‐h life‐span test, which can be attributed to the massive amount of amorphous AlF3 in H‐AlF3. H‐AlF3 contains the highest amount of acid and largest surface area among the AlF3 species. The synthetic route of CH3F showed higher conversion of raw material and better selectivity for CH3F than traditional routes. Fluoromethane was prepared via the vapor‐phase catalytic fluorination of CH3OCH3 by AlF3 catalyst. It was found that the amorphous AlF3 owned better activity than γ‐AlF3 or ɑ‐AlF3. [ABSTRACT FROM AUTHOR]

Aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF3) were analyzed by a set of characterization methods to assess their acidic properties: NH3-TPD, CO adsorption followed by DRIFTS, CD3CN-PAS-FTIR and MAS NMR spectroscopy after 15N-pyridine adsorption. Both catalysts contain very strong and medium-strong Lewis acid sites as confirmed by CO adsorption, in which small differences arise from the morphological properties of each catalyst, with ACF being microporous and HS-AlF3 mesoporous. Shifts of the CO vibration band of up to 77 cm−1 were observed, which account for very strong Lewis acid sites. In addition, very strong Lewis acid sites could be identified by CD3CN-PAS for both catalysts, exhibiting a shift of 95 cm−1 from free nitrile, the highest ever reported for a solid Lewis acid. [ABSTRACT FROM AUTHOR]

Abstract High strength, lightweight mullite whisker skeleton porous materials were prepared via novel facile nonaqueous precipitation method. The phase transition process of precipitate, microstructures and phase compositions of samples, and effects of aluminum fluoride amount on morphologies and properties of mullite whisker skeleton porous materials were investigated by DTA-TG, FE-SEM, XRD, the acid solubility and compressive strength tests. The growth direction of the whisker was determined. The growth mechanism of mullite whisker and formation mechanism of skeleton porous material were also investigated. The results show that the mullite phase forms at a low temperature of 900 °C via nonaqueous precipitation method, due to the formation of Al-O-Si bonds in the precipitate. The formation of mullite whiskers is controlled by gas-solid reaction and the whiskers grow along [001] direction. Well-developed mullite whiskers interlacedly grow into skeleton porous material at 1100 °C. The optimum mullite whisker skeleton porous material with the optimized aluminum fluoride amount of 1.3 of theoretical amount exhibits attractive properties of low density (1.21 g cm−3), high strength (158.6 MPa), low acid solubility (1.58 wt%), low thermal expansion coefficient (1.6 × 10−6 °C−1) and low thermal conductivity (0.28 W/(m K)). This material has the mean pore size of 542 nm and pore size distribution of 32–865 nm. It shows attractive application prospects in filtering and biomedical applications. [ABSTRACT FROM AUTHOR]

Aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF3) were analyzed by a set of characterization methods to assess their acidic properties: NH3-TPD, CO adsorption followed by DRIFTS, CD3CN-PAS-FTIR and MAS NMR spectroscopy after 15N-pyridine adsorption. Both catalysts contain very strong and medium-strong Lewis acid sites as confirmed by CO adsorption, in which small differences arise from the morphological properties of each catalyst, with ACF being microporous and HS-AlF3 mesoporous. Shifts of the CO vibration band of up to 77 cm−1 were observed, which account for very strong Lewis acid sites. In addition, very strong Lewis acid sites could be identified by CD3CN-PAS for both catalysts, exhibiting a shift of 95 cm−1 from free nitrile, the highest ever reported for a solid Lewis acid. [ABSTRACT FROM AUTHOR]

Highlights • The double layer model gives a good fit for acid-base titrations of MgOP. • MgOP can more easily adsorb H+ than OH− in water. • The pH values could affect the adsorption rate of fluoride on MgOP. • AlCl 3 could effectively neutralize the pH of fluoride solution treated by MgOP. • The complexation between Al3+ and F− may affect the fluoride adsorption process. Abstract The magnesia–pullulan composite (MgOP) achieved effective fluoride removal in previous research. In the present study, an acid-base titration experiment was conducted to investigate the properties of MgOP surface and further explore the mechanism of fluoride adsorption on MgOP. Results showed that the presence of chloride ions could improve fluoride adsorption on MgOP; however, additional nitrate ions had negligible impacts. A diffuse layer model and chemical equilibrium software (Visual MINTEQ 3.1) were used to simulate the acid-base titration data. The effects of initial pH values on the rate of fluoride uptake by MgOP were also studied. Moreover, aluminum salts were added to the fluoride solution with MgOP for the pH neutralization of treated water, in which aluminum chloride was preferred. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Highlights • La/Mg/Si-loaded palm shell-based activated carbon (LMSAC8) was synthesized via sonication followed by calcination. • The LMSAC8 composite showed superior aluminum and fluoride adsorption performance. • The kinetic uptake of aluminum and fluoride by LMSAC8 were well-described by the pseudo-second-order model. • The LMSAC8 composite exhibits an excellent regeneration and reusability performance after the five recycles. Abstract A novel La/Mg/Si-loaded, palm shell-based activated carbon (LMSAC) for the selective removal of aluminum and fluoride from water was synthesized through various methods. FESEM/EDX, BET, XRD, and FT-IR were utilized to characterize the synthetic LMSACs and investigate the aluminum and fluoride adsorption mechanisms of LMSAC prepared by sonication followed by calcination (LMSAC8). The adsorption kinetics, isotherms, and effects of pH and competing ions on the aluminum and fluoride uptake by LMSAC8 were evaluated. The maximum aluminum and fluoride adsorption capacities of LMSAC8 were 270.3 mg Al/g and 285.7 mg F/g at pH 7.0, respectively, which are much higher than those of the various adsorbents reported in the literature. Adsorption was highly dependent on the pH, which determines the distribution of aluminum and fluoride species in the solution. When common ions were present, LMSAC8 still exhibited good selectivity for aluminum and fluoride at a neutral pH. The aluminum and fluoride adsorption capacities of the regenerated LMSAC8 approached 80.7 and 77.0% of those of the fresh LMSAC8 after the five recycles. The adsorption experiments and FT-IR analysis revealed that the uptake of aluminum and fluoride can be attributed to complicated processes, including electrostatic interaction, inner sphere complexation via a ligand–exchange, and Lewis acid–base interactions. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

The significant role played by water in the mechanochemical synthesis of highly distorted aluminum hydroxide fluorides is on the main focus of this research paper. The importance of water in the synthesis was evaluated considering separately combinations of O/OH sources (Al(OH)3, Al2O3) and fluorine sources with or without structural water (β-AlF3.3H2O, α-AlF3). Each system was studied by typical bulk and surface characterization techniques (XRD, MAS NMR, DTA-TG, NH3-TPD) and compared to each other in order to gain a more comprehensive insight of the importance of including water in the synthesis of amorphous aluminum hydroxide fluorides. [ABSTRACT FROM AUTHOR]

Abstract: Porous aluminum fluoride‐supported noble metallic catalysts used for hydrodechlorination were investigated in the hydrodechlorination of 1‐chloroheptafluorocylopentene (F7‐1). The catalysts. Rh/porous aluminum fluoride (PAF) and Ru/PA.F were deactivated, and the activities of Pd/PAF and Pt/PAF reduced within 100 h. The above catalysts were characterized by the Brunauer–Emmett–Teller method, inductively coupled plasma mass spectrometry, X‐ray photoelectron spectroscopy, X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy. The characterization results indicated that the formation of noble metal chlorides, loss of active components, and carbonaceous deposition are the major causes of activity reduction or catalyst deactivation. The formation of aluminum chlorofluoride is also likely to have led to the decrease in the selectivity of the 1,1,2,2,3,3,4‐heptafluorocyclopentane (F7A) catalyst. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aluminium salts are widely investigated for the coagulation process for removal of fluoride, but the residual Al above the acceptable limit is the main concern which is mainly due to the formation of soluble and colloidal Al-F complexes of aluminium and fluoride. Hence, it is necessary to investigate the nature and mechanism of formation of colloidal, dissolved and precipitated Al-F complexes and other Al associated species, that govern the concentration of residual Al in the defluoridated water. In the present study, experiments were performed to find the optimized dosage of aluminium sulfate (alum) and polyaluminium (PACl) for removal of fluoride from drinking water. Residual fluoride, turbidity and TDS were found to be 1.3 ppm, 7 NTU & 280 ppm respectively, for alum and 0.48 ppm, 4 NTU & 200 ppm respectively for PACl for initial fluoride concentration of 4 ppm. Residual Al was found to be above the acceptable limit (0.2 ppm), but it was less for PACl as compared to alum, however, after the subsequent microfiltration, residual Al was 0.268 & 0.13 for alum & PACl respectively that almost met the acceptable limit. Characterization of the treated water before and after filtration by using microfiltration membrane was done through electrospray ionization mass spectroscopy (ESI-MS) to identify the colloidal, dissolved Al-F species. Aluminium species in the form AlF 5 2− ,AlF 2 + , AlF 4 − , Al 2 (OH) 2 2+ , Al(OH) 2 + , Al(OH) 2 F 2 − , AlOHF + etc. as Al-F were recognised. From the ESI-MS results, it was observed that only a few Al-F complexes with lesser concentrations were formed in case of PACl, which confirmed the fact that PACl worked better for the fluoride removal with low residual Al. The settling of the Al-F complexes for PACl was better than alum due to the difference in flocculation mechanism bridging in case of PACl and sweep flocculation for alum. XRD, SEM & FT-IR analysis of alum and PACl sludge was done to identify the precipitated species. [ABSTRACT FROM AUTHOR]

Quasibinary phase diagrams of the system “low-melting cryolite-Sc2O3” the potential media for synthesizing alloyed alloys Al-Sc are plotted by the method of thermal analysis. The phase diagrams of (KF-NaF-AlF3)-Sc2O3 with different content of NaF and the cryolite ratio (CR) 1.3 and 1.5 are the diagrams with simple eutectics. The liquidus temperature of the (KF-AlF3)-Sc2O3 system increases with the increase in the Sc2O3 concentration due to the formation of a high-melting compound: potassium hexafluoroscandiate К3ScF6. The solubility of Sc2O3 in low-melting cryolite melts KF-NaF-AlF3 increases with the increase in temperature and CR. In contrast Al2O3, the solubility of Sc2O3 in melts containing KF-AlF3 with CR = 1.3-1.5 is much lower than in cryolite melts containing NaF. The conductivity of low-melting cryolite melts measured by the method of impedance spectroscopy decreases in proportion to the Sc2O3 concentration in the similar way as in salt melts containing Al2O3. Based on the experimental data obtained, the compositions of low-melting cryolite melts are proposed for the synthesis of doped Al-Sc alloys. [ABSTRACT FROM AUTHOR]

Quasibinary phase diagrams of the system “low-melting cryolite-Sc2O3” the potential media for synthesizing alloyed alloys Al-Sc are plotted by the method of thermal analysis. The phase diagrams of (KF-NaF-AlF3)-Sc2O3 with different content of NaF and the cryolite ratio (CR) 1.3 and 1.5 are the diagrams with simple eutectics. The liquidus temperature of the (KF-AlF3)-Sc2O3 system increases with the increase in the Sc2O3 concentration due to the formation of a high-melting compound: potassium hexafluoroscandiate К3ScF6. The solubility of Sc2O3 in low-melting cryolite melts KF-NaF-AlF3 increases with the increase in temperature and CR. In contrast Al2O3, the solubility of Sc2O3 in melts containing KF-AlF3 with CR = 1.3-1.5 is much lower than in cryolite melts containing NaF. The conductivity of low-melting cryolite melts measured by the method of impedance spectroscopy decreases in proportion to the Sc2O3 concentration in the similar way as in salt melts containing Al2O3. Based on the experimental data obtained, the compositions of low-melting cryolite melts are proposed for the synthesis of doped Al-Sc alloys. [ABSTRACT FROM AUTHOR]

Gas-phase dehydrofluorination of 1,1,1,3,3-pentafluoropropane (HFC-245fa) to 1,3,3,3-tetrafluoropropene (HFO-1234ze), one of the new fourth-generation refrigerants was performed over the mesoporous nano -aluminum fluoride ( nano -AlF 3 ) synthesized through a facile polyol mediated sol-gel process. The solvent, molar ratio of HF/Al precursor and calcination temperature during preparation can affect the crystal structures and textural properties, especially the acidity amount of the resulting nano -AlF 3 . The prepared nano -AlF 3 catalysts exhibit the apparent reaction rate among 5.5–7.7 mmol h −1  g −1 with total selectivity above 97% to HFO-1234ze at 280 °C, which are higher than those on conventional β-AlF 3 and fluorinated Cr 2 O 3 catalysts. With regard to intrinsic reaction rate and apparent turn over frequency (TOF), β-AlF 3 displays the highest activity among the tested catalysts. The characterization results reveal that the density of acid sites of nano -AlF 3 is associated with its TOF in this reaction, and reducing the density of acid sites is beneficial to achieving high activity. However, the distribution of cis, trans-isomers for HFO-1234ze is not easily tuned by adjusting the preparation conditions of nano -AlF 3 . Catalytic stability tests show that nano -AlF 3 exhibits almost constant activity over 200 h, which are much more stable than conventional AlF 3 and fluorinated Cr 2 O 3 catalysts. [ABSTRACT FROM AUTHOR]

Porous mullite with interlocked needle shape microstructure was developed from China clay and aluminium fluoride trihydrate (AlF 3 ·3H 2 O). The effects of various parameters like sintering temperature, sintering time and the amount of AlF 3 ·3H 2 O on the phase evolution, microstructure and porosity have been studied. Quantitative analysis of mullite was carried out using X-ray diffraction combined with Rietveld-RIR method (Internal standard method). Porous mullite ceramics with 62% open porosity have been prepared at a relatively lower temperature of 1400 °C. The results show that the nucleation of mullite can be achieved from 700 °C onwards using hydrated aluminium fluoride without the formation of intermediate topaz crystals. The high amount of water vapour produced within the system during the in-situ reaction has a crucial role in deciding the reaction mechanism. [ABSTRACT FROM AUTHOR]

Introduction Equilibrium single-photon radionuclide imaging methods for assessing cardiac function and the integrity of the vascular system have long been in use for both clinical and research purposes. However, positron-emitting blood pool agents that could provide PET equivalents to these (and other) clinical procedures have not yet been adopted despite technical imaging advantages offered by PET. Our goal was to develop a PET blood pool tracer that not only meets necessary in vivo biological requirements but can be produced with an uncomplicated and rapid synthesis method which would facilitate clinical translation. Herein, albumin labeled with fluorine-18 was synthesized using a one-pot method and evaluated in vitro and in vivo in rats. Methods A ligand (NODA-Bz-TFPE), containing NODA attached to a tetrafluorophenylester (TFPE) via a phenyl linker (Bz), was labeled with aluminum fluoride (Al[ 18 F]F). Conjugation of the serum albumin with the ligand (Al[ 18 F]F-NODA-Bz-TFPE), followed by purification (size exclusion chromatography), yielded the final product (Al[ 18 F]F-NODA-Bz-RSA/HSA). In vitro stability was evaluated in human serum albumin by HPLC. Rat biodistributions and whole-body PET imaging over a 4 h time course were used for the in vivo evaluation. Results This synthesis exhibited an overall radiochemical yield of 45 ± 10% (n = 30), a 50-min radiolabeling time, a radiochemical purity >99% and apparent stability up to 4 h in human serum. Blood had the highest retention of Al[ 18 F]F-NODA-Bz-RSA at all times with a blood half-life of 5.2 h in rats. Al[ 18 F]F-NODA-Bz-RSA distribution in most rat tissues remained relatively constant for up to 1 h, indicating that the tissue radioactivity content represents the respective tissue plasma volume. Dynamic whole-body PET images were in agreement with these findings. Conclusions A new ligand has been developed and radiolabeled with Al[ 18 F]F that allows rapid (50-min) preparation of fluorine-18 serum albumin in one-pot. In addition to increased synthetic efficiency, the construct appears to be metabolically stable in rats. This method could encourage wider use of PET to quantify cardiac function and tissue vascular integrity in both research and clinical settings. [ABSTRACT FROM AUTHOR]

Individual transport numbers provide a measure of the charge ratio which is carried by each ionic species of an electrolyte. However, unlike the electrical conductivity or diffusion coefficients, this quantity lacks a clear definition from the statistical mechanics point of view. In practice, it is measured via complex experimental setups, and most of the interpretation of the available data is made by using the Nernst–Einstein approximation. Here we show that this approach is not suitable in molten salts due to the large contributions of the cross-terms due to the ionic interactions in the total ionic conductivity. We propose a partition scheme that allows to attribute these cross-terms to the various ions, allowing for an estimate of the transport numbers in a series of molten salt formed by mixing NaF and AlF 3 at various compositions. The results are interpreted using the speciation of the melt, which is characterized by the formation of various AlF x clusters. At large AlF 3 , the Na + ions are shown to contribute almost totally to the ionic conductivity. [ABSTRACT FROM AUTHOR]

Crystalline aluminum fluoride defects were observed on aluminum bond pads of wafers from a complementary metal oxide semiconductor process in a wafer fab after less than a month of storage. These defects were formed by reaction of moisture in the front opening unified pod wafer storage container with residual bond pad sidewall fluorocarbon etch polymer releasing gaseous HF which further reacted with nucleation sites on the bond pad aluminum surface, resulting in crystalline aluminum fluoride defects. Elimination of the residual bond pad fluorocarbon polymer using a polymer free etch process or high-efficiency postetch polymer solvent strip resulted in a significant improvement in crystalline defect-free storage time (6 months). However, 12 month storage of sidewall polymer-free wafers showed reappearance of crystalline aluminum fluoride defects. The fluorine source contributing to the appearance of long-term aluminum fluoride crystalline defects was surface fluorine in the top 50 Ǻ of the aluminum bond pad. Lowering the surface fluorine levels from 3%–4% to 1.5% (by Auger electron spectroscopy) resulted in up to 36 months defect-free wafer storage. Incorporating O2/H2 plasma resist strip and high-temperature polymer solvent strip into postetch processing were found to be effective surface fluorine reducing process strategies. [ABSTRACT FROM AUTHOR]

The facile, rapid and bulk production of composite materials consisting of carbon nanostructures doped with metal-based compounds has been a significant challenge for various research areas where such types of materials can be applied, including catalysis, energy storage and water purification. In this work, a carbon foam‑aluminum fluoride composite (C-AlF 3 ) was developed by adopting a combustion synthesis approach, which is an attractive alternative to wet chemical methods usually employed for such purposes. The flame ignition and combustion of a solid-state mixture comprising a fluoropolymer and nano-sized Al powder leads to the formation of a porous carbon foam network doped with dispersed cubic-like AlF 3 nanoparticles (100 to 500 nm in size), as observed by high-resolution microscopy methods. Selective area electron diffraction and X-ray diffraction studies revealed a rhombohedral α-AlF 3 crystal structure for these embedded particles, while micro-Raman spectroscopy indicated typical carbonaceous features for the foamy matrix. The C-AlF 3 composite also showed a combination of micro-, meso- and macro-porous characteristics (i.e. pore sizes in the nanometer scale) based on the analysis of N 2 sorption data collected at 77 K. The findings of this study provide useful insights for further research on carbon-based nanocomposite materials prepared via direct combustion synthesis routes. [ABSTRACT FROM AUTHOR]

A highly sensitive and selective fluorescence probe for H 2 O 2 has been developed based on an iminocoumarin derivative using aromatic boronic ester as sensing unit. A significant fluorescence enhancement was observed with λ max em = 619 nm when this probe was treated with H 2 O 2 . In the detection of H 2 O 2 , this probe exhibited a large Stokes shift (148 nm) and a low detection limit (6.0 × 10 −8  mol/L). Furthermore, cell imaging studies had revealed that this probe had the potential to detect intracellular H 2 O 2 in living cells. [ABSTRACT FROM AUTHOR]

Introduction: Aluminium Fluoride (AlF3) intake produces oxidative stress resulting in brain damage. Although, Mucuna pruriens (Velvet bean) is commonly used in ayurvedic system of medicine for different neurological disorders. Its usefulness in oxidative stress induced behavioural and neuronal damage has received little attention. Aim: This study was conducted to evaluate the neuroprotective role of Mucuna pruriens against AIF3 induced behavioural and neuronal changes in rats. Materials and Methods: Thirty six male Wistar albino rats were divided into six groups as: I-Normal saline; II-AIF3; III-25 mg/kg Quercetin and AlF3; IV, V and VI received 50, 100 and 200 mg/kg Mucuna pruriens methanolic extract and AlF3 (600 ppm). Extract was given for 10 days followed by AlF3 treatment for next seven days. Behavioural parameters were assessed such as T-maze test, actophotometer, and rotarod followed by histopathological studies. Results: A reduction in the locomotor activity, spatial learning and motor coordination was observed in the animals of Group II which reversed when treated with Mucuna pruriens. The histopathological studies of hippocampal CA1 region also showed the neuroprotective role of this plant which occurred due to oxidative stress. Conclusion: This study suggests the potential neuroprotective ability of Mucuna pruriens against the change in behaviour and neuronal damage which occurred due to induction of AIF3. [ABSTRACT FROM AUTHOR]

This study examined the catalytic properties of AlF 3 nanostructures for the hydrolysis of NF 3 discharged from semiconductor processes. Alumina being used as a catalyst for the hydrolysis of NF 3 was converted to AlF 3 by fluorination in the presence of NF 3 during a gas-solid chemical reaction. In general, AlF 3 has low catalytic activity in the hydrolysis of fluorinated compounds, but its catalytic activity varies according to its crystal structure. Commercial AlF 3 exhibited low catalytic activity in the hydrolysis of NF 3 , whereas AlF 3 formed from the chemical reaction between NF 3 and alumina exhibited very high catalytic activity. Although alumina has high catalytic activity in the hydrolysis of NF 3 , its activity decreases as it is converted to AlF 3 during the process. On the other hand, the activity test and X-ray diffraction showed that its catalytic activity is recovered as the nanocrystals of AlF 3 were grown. AlF 3 nanocrystals grown by the gas-solid chemical reaction showed a similar distribution of acid sites as the alumina. These acid sites provided the catalytic activity of AlF 3 in the hydrolysis of NF 3 . [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy is a suitable measurement method for the investigation of electrical conductivity of new types of aluminium electrolytes. Low-temperature electrolytes together with inert electrodes represent an innovation of the aluminium electrolysis process. Electrical conductivity, as one of the most important properties of electrolytes, has been investigated and described as part of the studied area of low-temperature sodium cryolite mixtures. Electrolytes used in this study contained high content of aluminium fluoride, up to 45 mol %; the molar ratio of NaF to AlF 3 in the melts varied from 2.0 to 1.2. Mutual influence of commonly used additives in industrial electrolytes (AlF 3 , Al 2 O 3 , CaF 2 , MgF 2 , LiF) and their temperature dependence was determined. Electrical conductivity was measured using a tube-type cell with stationary electrodes applying AC -techniques with a sine wave signal in the high frequency range. Concentration and temperature dependences of the electrical conductivity for all the studied low-temperature multi-component systems were described by the regression equation. [ABSTRACT FROM AUTHOR]