An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

An anion-doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF-teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF-teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel-Crafts products were formed.German Research Foundation http://dx.doi.org/10.13039/501100001659Diamond Light Source http://dx.doi.org/10.13039/100011889German Research Foundation http://dx.doi.org/10.13039/501100001659Peer Reviewe

An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

An anion‐doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF‐teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR‐IR spectra of adsorbed CD3CN reveal a blue‐shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF‐teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel‐Crafts products were formed

The effect of clothing fit and material of women’s Islamic sportswear on physiological and subjective responses during exercise in warm and humid environment

The purpose of this study was to investigate the effects of clothing fit and material of Islamic sportswear for female on physiological responses and body heat balance during exercise in warm and humid environment. Twelve healthy female students (20.3±0.4 years) exercised wearing four types of women’s Islamic sportswear comprised of two level of clothing fit: loose-fit and tight-fit, and two types of material for sportswear: cotton and polyester on four separate occasions, and in random order. They performed a 30-min treadmill exercise at an intensity of 70% HRmax and then rested on a chair for 20 min for recovery in a chamber set at an ambient temperature of 34°C and relative humidity of 80%. The results showed that clothing fit did not significantly affect physiological and subjective responses, but clothing material did; sportswear made of cotton resulted in a higher increase of tympanic temperature during exercise and recovery compared to that made of polyester (P<0.05). In addition, sportswear made of cotton have lower conductive and evaporative heat loss than sportswear made of polyester (P<0.05). Clothing fit only had significant effect on conductive heat loss; that is tight-fit sportswear showed greater conductive heat loss than loose-fit one (P <0.05). Regarding subjective responses, participants reported lower thermal comfort, greater thermal sensation, and greater skin wetness sensation when performing exercise wearing tight-fit sportswear made of polyester

A Combined Mg-25 Solid-State NMR and Ab Initio DFT Approach to Probe the Local Structural Differences in Magnesium Acetate Phases Mg(CH3COO)(2)center dot nH(2)O (n=0,1,4)

Multinuclear (H-1, C-13, Mg-25) solid-state NMR data is reported for a series of magnesium acetate phases Mg(CH3COO)(2)nH(2)O (n=0 (two polymorphs), 1, 4). The central focus here is Mg-25 as this set of compounds provides an expanded range of local magnesium coordinations compared to what has previously been reported in the literature using NMR. These four compounds provide 10 distinct magnesium sites with varying NMR interaction parameters. One of the anhydrous crystal structures () has an MgO7 site which is reported, to the best of our knowledge, for the first time. For those phases with a single crystal structure, a combination of magic angle spinning (MAS) NMR at high magnetic field (20T) and first principles density functional theory (DFT) calculations demonstrates the value of including Mg-25 in NMR crystallography approaches. For the second anhydrate phase (), where no single crystal structure exists, the multinuclear NMR data clearly show the multiplicity of sites for the different elements, with Mg-25 satellite transition (ST) MAS NMR revealing four inequivalent magnesium environments, which is new information constraining future refinement of the structure. This study highlights the sensitivity of Mg-25 NMR to the local environment, an observation important for several sub-disciplines of chemistry where the structural chemistry of magnesium is likely to be crucial

Ciprofloxacin, diclofenac, ibuprofen and 17α-ethinylestradiol differentially affect the activity of acetogens and methanogens in anaerobic communities

Pharmaceutical compounds end up in wastewater treatment plants but little is known on their effect towards the different microbial groups in anaerobic communities. In this work, the effect of the antibiotic Ciprooxacin (CIP), the non-steroidal anti-inammatory drugs Diclofenac (DCF) and Ibuprofen (IBP), and the hormone 17-ethinylestradiol (EE2), on the activity of acetogens and methanogens in anaerobic communities, was investigated. Microbial communities were more affected by CIP, followed by EE2, DCF and IBP, but the response of the different microbial groups was dissimilar. For concentrations of 0.01 to 0.1 mg/L, the specic methanogenic activity was not affected. Acetogenic bacteria were sensitive to CIP concentrations above 1 mg/L, while DCF and EE2 toxicity was only detected for concentrations higher than 10 mg/L, and IBP had no effect in all concentrations tested. Acetoclastic methanogens showed higher sensitivity to the presence of these micropollutants, being affect by all the tested pharmaceutical compounds although at different degrees. Hydrogenotrophic methanogens were not affected by any concentration, indicating their lower sensitivity to these compounds when compared to acetoclasts and acetogens.e Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Ana Rita Silva holds a Grant from FCT, reference SFRH/BD/131905/2017info:eu-repo/semantics/publishedVersio

Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

Vanadiumdotierte Metalloxide und -oxofluoride als Katalysatoren in selektiven Oxidationsreaktionen

In der vorliegenden Arbeit wurden unter Anwendung unterschiedlicher Präparationstechniken vanadiumdotierte Metalloxide bzw. –oxofluoride synthetisiert, umfassend charakterisiert und in katalytischen, selektiven Oxidationsreaktionen (ODH von Propan und Methanoloxidation) getestet. Die Festkörper- und oberflächenchemischen Eigenschaften wurden generell mittels CHN-Analyse, ICP-OES, XRD, Raman-, FTIR-, MAS-NMR- und ESR-Spektroskopie, Py-PAS, TPD und Tieftemperatur-Stickstoffadsorption untersucht. Ergänzend kamen an ausgewählten Proben der temperaturprogrammierte Sauerstoffisotopenaustausch und Adsorptionsuntersuchungen von Methanol zum Einsatz. Als katalytische Testreaktionen dienten die oxidative Dehydrierung von Propan und die selektive Methanoloxidation. Unabhängig von der angewendeten Synthesemethode zeigte sich, dass die Festkörpereigenschaften sowohl durch den Vanadiumgehalt, als auch wesentlich durch die Art des Wirtsgitters beeinflusst werden. Es konnte nachgewiesen werden, dass eine hohe Sauerstoffaustauschaktivität und das Vorhandensein Brønsted-saurer Zentren auf den Katalysatoroberflächen die Aktivierung der Edukte in den hier untersuchten katalytischen Reaktionen begünstigen. In Bezug auf die Selektivität zu den Zielprodukten Propen bzw. Formaldehyd sind diese Eigenschaften allerdings nachteilig, da an derartigen Zentren immer die Produkte der Totaloxidation (CO und CO2) gebildet werden. Besonders bemerkenswert ist das Verhalten der vanadiumdotierten Aluminiumoxofluoride. Diese Phasen wurden mit einer neuen Methode synthetisiert und enthalten fast ausschließlich Lewis-saure Zentren. Die Matrix wird zudem maßgeblich durch die Fluoridionen bestimmt, sodass die Sauerstoffmobilität und –austauschaktivität sehr gering sind. Dadurch reagieren sie, trotz einer relativ hohen katalytischen Aktivität, außerordentlich selektiv in den hier untersuchten selektiven Oxidationsreaktionen.In this thesis, vanadium containing metal oxides and oxyfluorides were prepared, thoroughly characterised and tested as catalysts in selective oxidation reactions. Bulk and surface properties of all samples were studied by means of CHN-analysis, ICP-OES, XRD, Raman-, FTIR-, MAS-NMR- und ESR-spectroscopy, Py-PAS, TPD and BET-adsorption. Moreover, the oxygen isotope exchange behaviour and the methanol adsorption properties of selected samples were analysed in order to correlate the surface properties with the catalytic behaviour of the materials. Irrespective of the preparation technique applied, the properties of the solids strongly depend on the host lattice as well as on the vanadium content. It has been clearly revealed that a high oxygen exchange activity and the presence of Brønsted acid sites on the catalyst surface promote the activation of the educts in selective oxidation reactions. The enhanced activity, however, is generally accompanied by a low selectivity towards the desired products propylene and formaldehyde, respectively. The low selectivity is caused by the high concentration of catalytically active sites leading to the formation of carbon oxides as total oxidation products of propane and methanol. A very promising catalytic behaviour was observed with vanadium-doped aluminium oxyfluorides. The oxyfluorides were prepared by a new method and contain almost exclusively Lewis-acid sites. The matrix is mainly determined by the fluoride anions resulting in a reduced oxygen mobility and exchange activity. Hence, the vanadium-doped aluminium oxyfluorides exhibit a relatively high catalytic activity accompanied by an excellent selectivity in the oxidation reaction of propane and methanol

Rohrverschleiss beim hydraulischen Feststofftransport

TIB: RN 7283 (16) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Sol-Gel-Synthesis of Nanoscopic Complex Metal Fluorides

The fluorolytic sol-gel synthesis for binary metal fluorides (AlF3, CaF2, MgF2) has been extended to ternary and quaternary alkaline earth metal fluorides (CaAlF5, Ca2AlF7, LiMgAlF6). The formation and crystallization of nanoscopic ternary CaAlF5 and Ca2AlF7 sols in ethanol were studied by 19F liquid and solid state NMR (nuclear magnetic resonance) spectroscopy, as well as transmission electron microscopy (TEM). The crystalline phases of the annealed CaAlF5, Ca2AlF7, and LiMgAlF6 xerogels between 500 and 700 °C could be determined by X-ray powder diffraction (XRD) and 19F solid state NMR spectroscopy. The thermal behavior of un-annealed nanoscopic ternary and quaternary metal fluoride xerogels was ascertained by thermal analysis (TG/DTA). The obtained crystalline phases of CaAlF5 and Ca2AlF7 derived from non-aqueous sol-gel process were compared to crystalline phases from the literature. The corresponding nanoscopic complex metal fluoride could provide a new approach in ceramic and luminescence applications.Peer Reviewe