- Metal-Free Photoredox-Catalyzed Hydrodefluorination of Fluoroarenes Utilizing Amide Solvent as Reductant
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A metal-free photoredox-catalyzed hydrodefluorination of fluoroarenes was achieved by using N,N,N’,N’-tetramethyl-para-phenylenediamine (1) as a strong photoreduction catalyst. This reaction was applicable not only to electron-rich monofluoroarenes but also to polyfluoroarenes to afford non-fluorinated arenes. The experimental mechanistic studies indicated that the amide solvent NMP plays an important role for regeneration of the photocatalyst, enabling additive-free photoreduction catalysis.
- Toriumi, Naoyuki,Yamashita, Kazuya,Iwasawa, Nobuharu
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supporting information
p. 12635 - 12641
(2021/08/03)
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- A structural, mechanistic, and kinetic study of the dehydrofluorination of 1,1,1,3,3-pentafluoropropane in the absence of catalyst
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The catalyst-free dehydrofluorination of 1,1,1,3,3-pentafluoropropane (HFC-245fa) was investigated both experimentally and theoretically to elucidate the mechanism and kinetics of the reaction. The experimental results demonstrated easier generation of E-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) than HFO-1234ze(Z) under the same reaction conditions within a temperature range of 500–700 °C. When analyzing the geometry, energetics, and kinetic modeling of the reaction at the B3LYP/6?311++G (d,p) level of theory, it was found that the thermodynamic stability of HFO-1234ze(E) is relatively higher than its isomer (HFO-1234ze(Z). Besides, the rate constants of HFO-1234ze(E) were always larger than those of HFO-1234ze(Z) at 400–2000 K, which agreed well with the higher selectivity of HFO-1234ze(E) in the synthetic experiment results. Our theoretical demonstration provides a reference to investigate the mechanism and kinetics of other analogous reactions.
- Jia, Xiaoqing,Lu, Fengniu,Qing, Feiyao,Quan, Hengdao,Ren, Yangyang
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- Biochemical Characterization, Phytotoxic Effect and Antimicrobial Activity against Some Phytopathogens of New Gemifloxacin Schiff Base Metal Complexes
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String of Fe(III), Cu(II), Zn(II) and Zr(IV) complexes were synthesized with tetradentateamino Schiff base ligand derived by condensation of ethylene diamine with gemifloxacin. The novel Schiff base (4E,4′E)-4,4′-(ethane-1,2-diyldiazanylylidene)bis{7-[(4Z
- Mohamed, Amira A.,Elshafie, Hazem S.,Sadeek, Sadeek A.,Camele, Ippolito
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- Stabilization of a mixed iron vanadium based hexagonal tungsten bronze hydroxyfluoride HTB-(Fe0.55V0.45)F2.67(OH)0.33as a positive electrode for lithium-ion batteries
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In our search for novel insertion compounds for Li-based batteries, we have identified a new mixed iron vanadium based Hexagonal Tungsten Bronze (HTB) type phase. Its synthesis involves two steps which consist first of preparing mixed metal hydrated fluoride Fe1.64V1.36F8(H2O)2 by a microwave assisted thermal process, followed by thermal treatment under air to obtain metastable HTB-(Fe0.55V0.45)F2.67(OH)0.33 hydroxyfluoride. 57Fe M?ssbauer spectrometry demonstrates the presence of oxidation states Fe2+ and Fe3+ in Fe1.64V1.36F8(H2O)2 as opposed to only Fe3+ in HTB-(Fe0.55V0.47)F2.67(OH)0.33. Moreover, the M?ssbauer spectra recorded at 77 K reveal that none of the compounds shows magnetic ordering owing to the presence of V3+ distributed over the crystallographic sites of Fe3+. Complementary X-ray spectroscopy and Rietveld refinement further confirm the successful synthesis of HTB-(Fe0.55V0.45)F2.67(OH)0.33. Electrochemically, the new HTB-(Fe0.55V0.45)F2.67(OH)0.33 shows a first discharge capacity of 181 mA h g-1 with 67percent of this capacity remaining upon cycling. Unlike HTB-FeF2.66(OH)0.34, the structure remains stable after the first discharge confirming the positive effect of vanadium in the HTB network. This journal is
- Grenèche, Jean-Marc,Hémon-Ribaud, Annie,Leblanc, Marc,Lemoine, Kévin,Lhoste, Jér?me,Maisonneuve, Vincent,Moury, Romain,Tarascon, Jean-Marie
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p. 8186 - 8193
(2020/07/10)
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- Structures and Properties of trans-1,3,3,3-Tetrafluoro- propene (HFO-1234ze) and 2,3,3,3-Tetrafluoropropene (HFO-1234yf) Refrigerants
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The refrigerant trans-1,3,3,3-tetrafluoropropene (HFO-1234ze) is used as a replacement for former cooling agents that have been phased-out due to their global warming potential or ozone depleting potential. Although it is used on a large scale, only a few vibrational data and no structural data of HFO-1234ze are known. We report structure determinations based on low-temperature single-crystal X-ray diffraction data as well as gas-phase diffraction data of HFO-1234ze and HFO-1234yf (2,3,3,3-tetrafluoropropene). Furthermore, vibrational spectra of HFO-1234ze in all phases are described. The results are discussed together with quantum-chemical calculations on the PBE0/cc-pVTZ level of theory. Combustion experiments of HFO-1234ze show carbonyl difluoride, carbon dioxide and hydrogen fluoride to be the main combustion products.
- Flierl, Lukas,Glodde, Timo,Kornath, Andreas J.,Mitzel, Norbert W.,Schwabedissen, Jan,Stammler, Hans-Georg,Vishnevskiy, Yury V.
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p. 921 - 928
(2020/10/06)
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- Synthesis and thermal stability of rare earth compounds REF3, REF3·nH2O and (H3O)RE3F10·nH2O (REu202f=u202fTb ? Lu, Y), obtained from sulphide precursors
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The nature of the interaction between sulphides of the rare-earth elements (RE) of the yttrium subgroup RE2S3 (Dy ? Lu, Y) with hydrofluoric acid (concentration of 49%) was studied. Powders of RE2S3 compounds were obtained by the reaction between RE2O3 (Dy ? Lu, Y) and Tb4O7 with a stream of H2S and CS2 in the 1000–1050 °C temperature range. The reaction between RE2S3 and HF was carried out in a glassy carbon crucible in the 21–25 °C temperature range in solution, and the precipitate was washed with H2O and dried at 90–100 °C. For the hydrates of RE fluorides with decreasing RE radius, the RE content increases the sorption of water for TbF3·0.5H2O; DyF3·0.5H2O; YF3·0.5H2O; HoF3·0.8H2O; and ErF3·0.9H2O. The powders of REF3·nH2O consisted of micro- and nano-sized particles containing the amorphous phase. Water loss occurs in the 50–180 °C temperature range and is accompanied by a natural increase in enthalpy: from 23.6 J/g for TbF3 · 0.5H2O to 97.8 J/g for ErF3·0.9H2O and from 51.1 J/g for (H3O)Tm3F10·1.7H2O to 64.5 J/g for (H3O)Lu3F10·0.9H2O. Exothermic effects of formation of polycrystalline phase REF3 were recorded in the 200–300 °C temperature range. The reaction of RE2S3 (Tm, Yb, Lu) powders with HF proceeds with the formation of the zeolite type compounds (H3O)Tm3F10·1.7H2O, (H3O)Yb3F10·1.0H2O and (H3O)Lu3F10·0.9H2O. Thermal dissociation occurs with gradual loss of water and HF to form RE fluorides with the β-YF3 structure as described by
- Andrrev,Razumkova,Boiko
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- Novel synthetic route to perfluoroallyl cyanide (PFACN) reacting perfluoroallyl fluorosulfonate with cyanide
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A novel synthetic method for the preparation of perfluoroallyl cyanide CF2[dbnd]CFCF2CN (PFACN) is presented. This includes the addition – elimination reaction of cyanide anion with perfluoroallyl fluorosulfate CF2[dbnd]CF
- Tverdomed, Sergey N.,Hirschberg, Markus E.,Pajkert, Romana,Hintzer, Klaus,R?schenthaler, Gerd-Volker
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- Comprehensive Insights into the Thermal Stability, Biodegradability, and Combustion Chemistry of Pyrrolidinium-Based Ionic Liquids
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The use of ionic liquids (ILs) as advanced electrolyte components in electrochemical energy-storage devices is one of the most appealing and emerging options. However, although ILs are hailed as safer and eco-friendly electrolytes, to overcome the limitations imposed by the highly volatile/combustible carbonate-based electrolytes, full-scale and precise appraisal of their overall safety levels under abuse conditions still needs to be fully addressed. With the aim of providing this level of information on the thermal and chemical stabilities, as well as actual fire hazards, herein, a detailed investigation of the short- and long-term thermal stabilities, biodegradability, and combustion behavior of various pyrrolidinium-based ILs, with different alkyl chain lengths, counteranions, and cations, as well as the effect of doping with lithium salts, is described.
- Eshetu, Gebrekidan Gebresilassie,Jeong, Sangsik,Pandard, Pascal,Lecocq, Amandine,Marlair, Guy,Passerini, Stefano
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p. 3146 - 3159
(2017/08/18)
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- Multi-emitter chemiluminescence in the solid-phase interaction of xenon difluoride with uranyl hydrogen phosphate
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Chemiluminescence (CL) was found in the solid-phase interaction of xenon difluoride with uranyl hydrogen phosphate; the CL emitters are *Xe, UO22+ and the singlet oxygen dimole (1O2)2.
- Ostakhov, Sergey S.,Masyagutova, Gul'shat A.,Mamykin, Alexander V.,Khursan, Sergey L.
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p. 405 - 406
(2016/10/05)
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- Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid
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The photoabatement of perfluorooctanoic acid in aqueous solution has been performed with a commercial nano-sized TiO2-based photocatalyst content of 0.66 g/L under an UV irradiation of 95 W/m2. PFOA degradation intermediates were investigated by HPLC-MS and 19F-NMR analysis. Evidences of a degradation mechanism based on two competitive pathways are discussed: photo-redox and β-scission pathways. Shorter perfluorinated carboxylic acids, CnF2n+1COOH (n = 1-6), as expected degradation intermediates, were identified and their concentration trends over time were determined. The apparent pseudo-first order kinetic constant expressed as rate of PFOA disappearance was also measured: kapp 0.1296 h-1. The influence of fluoride ions on TiO2 surface was analyzed by XPS technique, revealing a surface modification that affects the performances of the catalyst.
- Gatto, Sara,Sansotera, Maurizio,Persico, Federico,Gola, Massimo,Pirola, Carlo,Panzeri, Walter,Navarrini, Walter,Bianchi, Claudia L.
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- The rate of the F + H2 reaction at very low temperatures
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The prototypical F + H2 → HF + H reaction possesses a substantial energetic barrier (~800 K) and might therefore be expected to slow to a negligible rate at low temperatures. It is, however, the only source of interstellar HF, which has been detected in a wide range of cold (10-100 K) environments. In fact, the reaction does take place efficiently at low temperatures due to quantum-mechanical tunnelling. Rate constant measurements at such temperatures have essentially been limited to fast barrierless reactions, such as those between two radicals. Using uniform supersonic hydrogen flows we can now report direct experimental measurements of the rate of this reaction down to a temperature of 11 K, in remarkable agreement with state-of-the-art quantum reactive scattering calculations. The results will allow a stronger link to be made between observations of interstellar HF and the abundance of the most common interstellar molecule, H 2, and hence a more accurate estimation of the total mass of astronomical objects.
- Tizniti, Meryem,Le Picard, Sebastien D.,Lique, Francois,Berteloite, Coralie,Canosa, Andre,Alexander, Millard H.,Sims, Ian R.
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p. 141 - 145
(2014/02/14)
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- Reactivity in the nucleophilic aromatic substitution reactions of pyridinium ions
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The "element effect" in nucleophilic aromatic substitution reactions (SNAr) is characterized by the leaving group order, L = F > NO2 > Cl ≈ Br > I, in activated aryl substrates. A different leaving group order is observed in the subs
- Bowler, Jeannette T.,Wong, Freeman M.,Gronert, Scott,Keeffe, James R.,Wu, Weimings
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p. 6175 - 6180
(2014/08/05)
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- Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine
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Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe III(μ-N)FeIV(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)FeIV(μ-N)FeIV(F) (Pc+?)], which was isolated and characterized by UV-vis, EPR, 19F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)FeIII(μ-N)Fe IV(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H 3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.
- Colomban, Cédric,Kudrik, Evgenij V.,Afanasiev, Pavel,Sorokin, Alexander B.
-
supporting information
p. 11321 - 11330
(2014/11/07)
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- High-yield synthesis of single-crystal silicon nanoparticles as anode materials of lithium ion batteries via photosensitizer-assisted laser pyrolysis
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Single crystal silicon nanoparticles (Si-NPs) of 20 nm were produced via laser pyrolysis with a virtually complete conversion from SiH4 to Si-NPs. SF6 was used as the photosensitizer to transfer laser beam energy to silicon precursor
- Kim, Seongbeom,Hwang, Chihyun,Park, Song Yi,Ko, Seo-Jin,Park, Hyungmin,Choi, Won Chul,Kim, Jong Bok,Kim, Dong Suk,Park, Soojin,Kim, Jin Young,Song, Hyun-Kon
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p. 18070 - 18075
(2015/02/02)
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- Reaction of limonene with F2: Rate coefficient and products
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The kinetics of the reaction of limonene (C10H16) with F2 has been studied using a low pressure (P = 1 Torr) and a high pressure turbulent (P = 100 Torr) flow reactor coupled with an electron impact ionization and chemical ionization mass spectrometers, respectively: F2 + Limonene → products (1). The rate constant of the title reaction was determined under pseudo-first-order conditions by monitoring either limonene or F2 decay in excess of F2 or C10H16, respectively. The reaction rate constant, k1 = (1.15 ± 0.25) × 10-12 exp(160 ± 70)/T) was determined over the temperature range 278-360 K, independent of pressure between 1 (He) and 100 (N2) Torr. F atom and HF were found to be formed in reaction 1, with the yields of 0.60 ± 0.13 and 0.39 ± 0.09, respectively, independent of temperature in the range 296-355 K. (Graph Presented).
- Bedjanian, Yuri,Romanias, Manolis N.,Morin, Julien
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p. 10233 - 10239
(2015/02/19)
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- Ion chemistry of sulfuryl fluoride: An experimental and theoretical study on gas-phase reactions involving neutral and ionized SO2F2
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The gas phase ion chemistry of sulfuryl fluoride is studied by ion trap mass spectrometry and ab initio calculations. Reactions of ions of atmospheric relevance with neutral SO2F2 mainly result in SO 2F2 depletion by dissociative electron transfer. In few cases, a different reaction mechanism involving F-abstraction is invoked, since dissociative ion products are observed despite the electron transfer channel being endothermic. Ab initio calculations revealed a nearly perfect distonic structure for the molecular SO2F2+ ion, whose capability of activating strong HX bonds (X = C, N, O) is ascribable to the high spin density located on the oxygen atoms, in line with literature reports. Among the ions produced by electron ionization of SO2F2, the FSOx+ (x = 0-2) ions are capable of activating the HNH2 bond of ammonia. Theoretical investigation revealed that NH 3 activation by SF+ requires a triplet to singlet conversion along the reaction pathway. This conversion is expected to be fast, the conceivable reaction rate determining step being the subsequent intramolecular hydrogen migration.
- Antoniotti, Paola,Benzi, Paola,Operti, Lorenza,Rabezzana, Roberto,Borocci, Stefano,Giordani, Maria,Grandinetti, Felice
-
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- A facile method for construction of a functionalized multi-layered separator to enhance cycle performance of lithium manganese oxide
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A facile approach has been proposed to improve the cycle performance of LiMn2O4-based cathodes by chemical modification of the separator. This strategy is based on the construction of a multilayer structure consisting of an interlayer with polar hydroxyl (OH) groups to promote the chemical reactivity between a hydrophobic separator and a surface layer with a HF scavenger to remove any HF remaining in the electrolyte. Systematic studies performed in this work indicate that separator functionalization is effective in increasing the structural stability of LiMn2O4 cathodes.
- Yim, Taeeun,Ha, Hyo-Jeong,Park, Min-Sik,Kim, Ki Jae,Yu, Ji-Sang,Kim, Young-Jun
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p. 25657 - 25661
(2013/12/04)
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- Standard enthalpy of formation of nickel trifluoride by isothermal calorimetry
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The change in enthalpy in reactions of NiF3(s) with water and aqueous solution of potassium hydroxide are measured in the isothermal calorimetry mode at 298.15 K. The standard enthalpy of formation ΔfH° of nickel trifluoride was foun
- Solov'ev,Korunov,Zubkov,Firer
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p. 516 - 518
(2012/07/14)
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- Diels-Alder reactions of perfluoroketene dithioacetals with electron-rich 1,3-dienes: A new access to polysubstituted aromatic sulfides
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The present paper describes the Diels-Alder reactions of perfluoroketene dithioacetals with electron-rich 1,3-dienes (2,3-dimethylbuta-1,3-diene, isoprene, penta-1,3-diene) followed by spontaneous HF and thiol elimination, leading to polysubstituted aromatic sulfides in moderate to good yields. Reactions seem to be dependent on the substitution patterns of perfluoroketene dithioacetals; the best results were obtained from trifluoromethyl or pentafluoroethyl and ethylsulfanyl derivatives. Theoretical calculations performed at the DFT level are in good agreement with the experimental results and show that the overall process is controlled by the cycloaddition step.
- Bouillon, Jean-Philippe,Mykhaylychenko, Sergiy,Melissen, Sigismund,Martinez, Agathe,Harakat, Dominique,Shermolovich, Yuriy G.
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p. 8663 - 8669
(2012/10/29)
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- Kinetics and mechanism of the reaction of fluorine atoms with trifluoroacetic acid
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The kinetics of the reaction between fluorine atoms and trifluoroacetic acid has been studied experimentally at T = 258-343 K. The overall reaction rate constant decreases with temperature: k1(T) = 1.09 × 10 -12 exp((+1034 K)/T) cm3 molecule-1 s -1. The potential energy surface of the reaction has been studied using quantum chemistry. The results were used in transition state theory calculations of the temperature dependences of the rate constants of the two channels of the reaction. The abstraction channel ultimately producing HF is dominant at the experimental temperatures; the addition-elimination channel producing CF3 and CF(O)OH becomes important above 1000 K.
- Vasiliev,Knyazev,Savelieva,Morozov
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p. 172 - 177
(2011/11/30)
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- Preparation and characterization of high-purity metal fluorides for photonic applications
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We combine chelate-assisted solvent extraction (CASE) and hot hydrogen fluoride gas treatment to enable a general method for the preparation of high-purity binary metal fluorides. The fluorozirconate glass ZBLANI:Yb 3+ (ZrF4-BaF2-LaF3-AlF 3-NaF-InF3-YbF3), a solid-state laser-cooling material, is used as a test case to quantitatively assess the effectiveness of the purification method. The reduction of transition-metal and oxygen-based impurities is quantified directly by inductively coupled plasma mass spectrometry (ICP-MS) and indirectly by laser-induced cooling, respectively. The concentrations of Cu, Fe, Co, Ni, V, Cr, Mn, and Zn impurities in the ZrCl 2O precursor solution were measured individually by ICP-MS at various stages of the purification process. CASE was found to reduce the total transition-metal concentration from 72500 to ~100 ppb. Laser cooling was most efficient in ZBLANI:Yb3+ glass fabricated from CASE-purified metal fluoride precursors, confirming the results of the ICP-MS analysis and demonstrating the effectiveness of the purification methods in a finished optical material. High-purity metal fluorides prepared by the methods presented herein will enable new high-performance optical materials for solid-state optical refrigerators, crystals for vacuum ultraviolet (VUV) spectroscopy of the Thorium-229 nucleus, VUV optics, fibers, and thin-film coatings.
- Patterson, Wendy M.,Stark, Peter C.,Yoshida, Thomas M.,Sheik-Bahae, Mansoor,Hehlen, Markus P.
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p. 2896 - 2901
(2011/12/22)
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- Cationic and radical intermediates in the acid photorelease from aryl sulfonates and phosphates
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The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (≈0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with phosphates and (mainly) radical with sulfonates. The Royal Society of Chemistry and Owner Societies 2011.
- Terpolilli, Marco,Merli, Daniele,Protti, Stefano,Dichiarante, Valentina,Fagnoni, Maurizio,Albini, Angelo
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experimental part
p. 123 - 127
(2012/01/03)
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- Thermoanalytical and structural characterization of fluoridated calcium phosphates prepared in anhydrous alcohols
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A thermoanalytical, morphological, and structural study of fluoridated calcium phosphates that were prepared by different variants of a synthesis in anhydrous alcohols is reported. The obtained materials were neither fully amorphous nor single-phased crystalline, and their nature considerably depended on the synthesis conditions. In all cases, the retention of significant amounts of solvent in the solid product was observed. A complete removal of the solvent was only possible by heating to temperatures above ~573-673 K which resulted in variations in the elemental composition, phase changes, and an increase of the crystallinity. Consequently, this synthesis in anhydrous alcohols is not a viable route to obtain materials with a defined crystallinity and stoichiometry.
- Simoes, Ricardo G.,Aleixo, Ana I.,Lagoa, Ana L. C.,Minas Da Piedade, Manuel E.,Leal, Joao P.,Peitsch, Thorsten,Epple, Matthias
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p. 509 - 517
(2010/08/05)
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- Unimolecular rate constant and threshold energy for the HF elimination from chemically activated CF3CHFCF3
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Combination of CF3CHF and CF3 radicals at room temperature generated chemically activated CF3CHFCF3 molecules with 95 ± 3 kcal/mol of internal energy that decompose by loss of HF, initially attached to adjacent carbons, with an experimental unimolecular rate constant of (4.5 ± 1.1) x 102 s-1. Density functional theory was used to model the unimolecular rate constant for HF elimination, kHF, to determine a threshold energy of 75 ± 2 kcal/mol.
- Duncan, Juliana R.,Roach, Michael S.,Stiles, Brooke Sibila,Holmes, Bert E.
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p. 6996 - 7002
(2011/02/16)
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- Fluoride ion donor properties of group 13 trifluorides (MF3, M = Al, Ga, In, Tl) and crystal structures of InF3·3SbF 5, TlF3·3SbF5 and TlF 3·AsF5·2HF
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Reactions between strong Lewis acids (i.e. AsF5, SbF 5) and MF3 (M = Al, Ga, In, Tl) in anhydrous hydrogen fluoride at ambient temperature proceeded only in three cases, yielding InF 3·3SbF5, TlF3·3SbF5, TlF3·AsF5·2HF and TlF3· AsF5. Crystal structure of InF3·3SbF5 consists from infinite chains of In atoms connected by three SbF6 units, with two bridging fluorine atoms (Fb) in cis-position. Due to the strong interaction of SbF6 units with In3+, the Sb-Fb bonds are significantly elongated (200.7(4) pm). Such long Sb-Fb bonds have been observed in the crystal structure of SbF 5. The crystal structure of TlF3·3SbF5 is built from slabs where thallium atoms are connected by SbF6 units. The thallium is nine-fold coordinated by fluorine atoms in the shape of a tricapped trigonal prism. In the crystal structure of TlF3· AsF5·2HF there are puckered layers, composed of rectangular rings made of Tl and F atoms. The seven-fold coordination around each Tl is completed by three axial fluorine atoms, provided by one HF molecule and two AsF6 units arranged below and above the puckered layers forming infinite slabs on that way. The second molecule of HF is placed between the slabs. Vibrational spectra of isolated InF3·3SbF5, TlF3·3SbF5, and TlF3·AsF 5 are consistent with the presence of highly deformed SbF 6/AsF6 octahedra. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Mazej, Zoran,Goreshnik, Evgeny
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p. 2806 - 2812
(2011/02/18)
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- Sulfuric acid breakdown of fluorite in the presence of silica
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We study the reaction of CaF2 with concentrated sulfuric acid in the presence of silica at 120 and 140°C using fluorite mineral, fluorite concentrate, and mica-fluorite ore samples. When steam is fed to the reaction mixture, fluorosilicic acid
- Krysenko,Gordienko,Epov
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p. 1876 - 1879
(2010/05/01)
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- OXONIUM AND SULFONIUM SALTS
-
The present invention relates to oxonium salts having [(Ro)3O]+ cations and sulfonium salts having [(Ro)3S]+ cations, where Ro denotes straight-chain or branched alkyl groups having 1-8 C atoms or phenyl which is unsubstituted or substituted by Ro, ORo, N(Ro)2, CN or halogen, and anions selected from the group of [PFx(CyF2y+1?zHz)6?x]? anions, where 2≦x≦5, 1≦y≦8 and 0≦z≦2y+1, or anions selected from the group of [BFn(CN)4?n]? anions, where n=0, 1 , 2 or 3, or anions selected from the group of [(Rf1SO2)2N]? anions or anions selected from the group of [BFwRf24?w]? anions, to processes for the preparation thereof, and to the use thereof, in particular for the preparation of ionic liquids.
- -
-
Page/Page column 11
(2009/03/07)
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- Solid-state and solution rearrangements of F3S≡NXeF + leading to the F4S=NXe+ cation; syntheses, HF solvolyses, and structural characterizations of [F4S=NXe][AsF 6] and ...
-
The salt, [F 4 S=NXe][AsF 6 ], has been synthesized bythe solid-state rearrangement of [F 3 S≡NXeF][AsF 6] and by HF-catalyzed rearrangement of [F 3 StNXeF][AsF 6 ] in anhydrous HF (aHF) and HF/BrF 5 solvents. The F 4 S=NXe + cation undergoes HF solvolysis to form F 4 S=NH 2 + , XeF 2 , and the recently reported F 5 SN(H)Xe + cation. Both [F 4 S=NXe][AsF 6 ] and [F 4 S=NH 2 ][AsF 6 ] have been characterized by 129 Xe and 19 F NMR spectroscopy in aHF and HF/BrF 5 solvents and by single-crystal X-ray diffraction. The [F 4 S=NXe][AsF 6 ] salt was also characterized by Raman spectroscopy. The Xe-N bond of F 4 S=NXe + is among the shortest Xe-N bonds presently known (2.084(3) ?), and the cation interacts with the AsF 6 - anion by means of a Xe - FsAs bridge in which the Xe - F distance (2.618(2) ?) is significantly less than the sum of the Xe and F van der Waals radii. Both F 4 S=NXe + and F 4 S=NH 2 + exhibit trigonal bipyramidal geometries about sulfur, with nitrogen in the equatorial plane and the nitrogen substituents coplanar with the axial fluorine ligands of sulfur. The F 4 S=NH 2 + cation is isoelectronic with F 4 S=CH 2 and, like F 4 S=CH 2 , has a high barrier to rotation about the S=N double bond and to pseudorotation of the trigonal bipyramidal F 4 S=N- moiety. The solution and solid-state rearrangements of F 3 S≡NXeF + to F 4 S= NXe + are proposed to result from attack at sulfur byfluoride ion arising from HF in solution and from the AsF 6 - anion in the solid state. Quantum-chemical calculations were employed to calculate the gas-phase geometries, charges, bond orders, valencies, and vibrational frequencies of F 4 S=NXe + and F 4 S=NH 2 + . The F 4 S=NXe + cation provides the first example of xenon bonded to an imido-nitrogen, and together with the F 4 S=NH 2 + cation are presently the only cations known to contain the F 4 S=N-group. Both cations are intermediates in the HF solvolysis pathways of F 3 S≡NXeF + which lead to F 5 SN(H)Xe + and F 5 SNH 3 + , and significantly extend the chemistry of the F 4 S=N-group.
- Smith, Gregory L.,Mercier, Helene P. A.,Schrobilgen, Gary J.
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p. 7272 - 7286
(2009/10/17)
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- Effect of heat treatment in HF atmosphere on the optical and electrical properties of BaF2 ceramics
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Using optical spectroscopy and complex impedance measurements, we have studied the transmission spectra and electrical conductivity of different BaF2 samples: ceramic prepared by vacuum hot pressing (200 MPa, 870°C, 20 min), the same ceramic af
- Sorokin,Karimov,Komar'Kova,Krivandina,Smirnov,Chernov,Sobolev
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p. 1188 - 1192
(2009/12/25)
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- On the XeF+/H2O system: Synthesis and characterization of the xenon(II) oxide fluoride cation, FXeOXeFXeF+
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The reported synthesis of the H2OF+ cation as a product of the oxidative fluorination of H2O by [XeF][PnF 6] (Pn = As, Sb) in HF solution has been reinvestigated. The system exhibits complex equilibria, producin
- Gerken, Michael,Moran, Matthew D.,Mercier, Helene P. A.,Pointner, Bernard E.,Schrobilgen, Gary J.,Hoge, Berthold,Christe, Karl O.,Boatz, Jerry A.
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p. 13474 - 13489
(2009/12/27)
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- Mechanism of ketone hydrosilylation by Cu(I) catalysts: A theoretical study
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The plausibility of the catalytic cycle suggested for the hydrosilylation of ketones by Cu(I) hydrides has been investigated by a theoretical DFT study. A model system made up of a CuH(PH3)2 catalyst, acetone and SiH4 give
- Gathy, Thomas,Peeters, Daniel,Leyssens, Tom
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p. 3943 - 3950
(2010/03/01)
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- Method For Producing Carbonyl Difluoride
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The present invention relates to a method for producing carbonyl difluoride comprising a step of reacting trifluoromethane with oxygen or an oxygen-containing gas while heating.
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Page/Page column 4-5
(2008/06/13)
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- Probing the reactivity of the potent AgF2 oxidizer. Part 2: Inorganic compounds
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The reactivity of AgIIF2 towards forty two inorganic compounds containing oxo- and chloro- ligands, has been investigated. Five families of compounds were studied: (i) binary oxides of metals and nonmetals, (ii) ternary salts of inor
- Malinowski, Przemyslaw,Mazej, Zoran,Grochala, Wojciech
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p. 2608 - 2616
(2009/05/09)
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- Quantum state resolved scattering dynamics of F+HCl→HF (v,J) +Cl
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State-to-state reaction dynamics of the reaction F+HCl→HF (v,J) +Clhave been studied under single-collision conditions using an intense di scharge F atom source in crossed supersonic molecular beams at Ecom =4.3(1.3) kcalmol. Nascent HF product is monitored by shot-noise limited di rect infrared laser absorption, providing quantum state distributions aswell as additional information on kinetic energy release from high reso lution Dopplerimetry. The vibrational distributions are highly inverted,with 34(4)percent, 44(2)percent, and 8(1)percent of the total populatio n in vHF =1, 2, and 3, respectively, consistent with predominant energy release into the newly formed bond. However, there is a small [14(1)percent] but significant formation channel into the vHF =0 ground state, which is directly detectable for the first time via direct absorption methods. Of particular dynamical interest, both the HF (v=2,J) and HF (v=1,J)populations exhibit strongly bimodal J distributions. These results dif fer significantly from previous flow and arrested-relaxation studies andmay signal the presence of microscopic branching in the reaction dynami cs.
- Zolot, A. M.,Nesbitt, D. J.
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-
- Kinetics of sulfur oxide, sulfur fluoride, and sulfur oxyfluoride anions with atomic species at 298 and 500 K
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The rate constants and product-ion branching ratios for the reactions of sulfur dioxide (SO2-), sulfur fluoride (SF n-), and sulfur oxyfluoride anions (SOxF y-) with H, H2, N, N2, NO, and O have been measured in a selected-ion flow tube (SIFT). H atoms were generated through a microwave discharge on a H2/He mixture, whereas O atoms were created via N atoms titrated with NO, where the N had been created by a microwave discharge on N2. None of the ions reacted with H 2, N2 or NO; thus, the rate constants are -12 cm3 s-1. SOxFy - ions react with H by only fluorine-atom abstraction to form HF at 298 and 500 K. Successive F-atom removal does not occur at either temperature, and the rate constants show no temperature dependence over this limited range. SO2- and F- undergo associative detachment with H to form a neutral molecule and an electron. Theoretical calculations of the structures and energetics of HSO2- isomers were performed and showed that structural differences between the ionic and neutral HSO 2 species can account for at least part of the reactivity limitations in the SO2- + H reaction. All of the SOxF y- ions react with O; however, only SO2 - reacts with both N and O. SOxFy- reactions with N (SO2- excluded) have a rate constant limit of -11 cm3 s-1. The rate constants for the SOxFy- reactions with H and O are ≤25% of the collision rate constant, as seen previously in the reactions of these ions with O3, consistent with a kinetic bottleneck limiting the reactivity. The only exceptions are the reactions of SO2 - with N and O, which are much more efficient. Three pathways were observed with O atoms: F-atom exchange in the reactant ion, F- exchange in the reactant ion, and charge transfer to the O atom. No associative detachment was observed in the N- and O-atom reactions.
- Midey, Anthony J.,Viggian
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p. 1852 - 1859
(2008/10/09)
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- Seven-coordinate iron complex as a ditopic receptor for lithium salts: Study of host-guest interactions and substitution behavior
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Interactions between the seven-coordinate tweezerlike [Fe(dapsox)(H 2O)2]ClO4 complex (H2dapsox = 2,6-diacetylpyridine-bis(semioxamazide)) with different lithium salts (LiOTf, LiClO4, LiBF4, and LiPF6) in CH3CN have been investigated by electrochemical, spectrophotometric, 7Li and 19F NMR, kinetic, and DFT methods. It has been demonstrated that this complex acts as ditopic receptor, showing spectral and electrochemical ion-pair-sensing capability for different lithium salts. In general, the apparent binding constants for lithium salts increase in the order LiOTf 4 4. From the electrochemical measurements, the apparent lithium salt binding constants for the Fe(III) and Fe(II) forms of the complex have been obtained, suggesting a stronger host-guest interaction with the reduced form of the complex. In the presence of LiPF6, the solution chemistry is more complex because of the hydrolysis of PF 6-. The kinetics of the complexation of [Fe(dapsox)(CH3CN)2]+ by thiocyanate at -15°C in acetonitrile in the presence of 0.2 M NBu4OTf shows two steps with the following rate constants and activation parameters: k1 = 411 ± 14 M-1 s-1; ΔH1 ≠ = 9 ± 2 kJ mol-1; ΔS1 ≠ = -159 ± 6 J K-1 mol-1; k 2 = 52 ± 1 M-1 s-1; ΔH 2≠ = 4 ± 1 kJ mol-1; ΔS 2≠ = -195 ± 3 J K-1 mol-1. The very negative ΔS≠ values are consistent with an associative (A) mechanism. Under the same conditions but with 0.2 M LiOTf, k1Li and k2Li are 1605 ± 51 and 106 ± 2 M-1 s-1 respectively. The increased rate constants for the {[Fe(dapsox)(CH3CN)2]-LiOTf}+ adduct are in agreement with an associative mechanism. Kinetic and spectrophotometric titration measurements show stronger interaction between the lithium salt and the anion-substituted forms, [Fe(dapsox)(CH3CN)(NCS)] and [Fe(dapsox)(NCS)2]-, of the complex. These experiments demonstrate that in nonaqueous media lithium salts cannot be simply used as supporting electrolytes, since they can affect the kinetic behavior of the studied complex. DFT calculations revealed that the negatively charged α-oxyazine oxygen atoms are responsible for cation binding (electrostatic interactions), whereas the two terminal amide groups bind the anion via hydrogen bonding.
- Sarauli, David,Popova, Vesselina,Zahl, Achim,Puchta, Ralph,Ivanovic-Burmazovic, Ivana
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p. 7848 - 7860
(2008/10/09)
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- Formation of monofluorophosphate from fluoride in phosphoric acid - Water and phosphoric acid - sulfuric acid - water mixtures
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When dissolved in concentrated phosphoric acid, sodium fluoride reacts rapidly to form monofluorophosphate. In less concentrated acid, the reaction does not proceed to completion, and the reaction kinetics become very much slower. The equilibrium and rate
- Newman, Kenneth E.,Ortlieb, Raymond E.,Pawlik, Nicole,Reedyk, Jason
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p. 346 - 351
(2008/03/13)
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- Two organically templated niobium and zinconiobium fluorophosphates: Low temperature hydrothermal syntheses of NbOF(PO4)2(C 2H10N2)2 and Zn3(NbOF) (PO4)4(C2H10N2) 2
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Two new niobium and zinconiobium fluorophosphates, NbOF(PO 4)2(C2H10N2)2 (1) and Zn3(NbOF)(PO4)4-(C2H 10N2)2 (2), have been prepared under hydrothermal conditions using ethylenediamine as a template. The structures were determined by single crystal diffraction to be triclinic, space group P1 (No. 2), a = 8.1075 (6) A, b = 9.8961 (7) A, c = 10.1420(8) A, α = 111.655(1)°, β = 111.51(1)°, γ = 93.206(1)°, V = 686.19(9) A3, and Z = 2 for 1 and orthorhombic, space group Fddd (No. 70), a = 9.1928(2) A, b = 14.2090(10) A, c = 32.2971 (6) A, V = 4218.66(12) A3, and Z = 8 for 2, respectively. Compound 1 is an infinite linear chain consisting of corner-sharing [Nb 2P2] 4-MRs bridged at the Nb centers with organic amines situated between chains, and compound 2, containing the chains similar to that in 1, forms a zeotype framework with organic amines situated in the gismondine-type [4684] cavities. The topology of 2 was previously unknown with vertex symbol 4·4·4·4· 8·8 (vertex 1), 4·4·4·82·8· 8 (vertex 2), 4·4·8·8·82·8 2 (vertex 3), and 4·4·4·8 2·8·8 (vertex 4). The topological relationships between the 4-connected network of 2 and several reported (3,4)-connected networks were discussed.
- Liu, Guang-Zhen,Zheng, Shou-Tian,Yang, Guo-Yu
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p. 231 - 237
(2008/10/09)
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- Vibrational overtone spectrum of matrix isolated cis, cis-HOONO
-
Cis, cis-peroxynitrous acid is known to be an intermediate in atmospheric reactions between OH and N O2 as well as HOO and NO. The infrared absorption spectra of matrix-isolated cc-HOONO and cc-DOONO in argon have been observed in the range of 500-8000 cm-1. Besides the seven fundamentalvibrational modes that have been assigned earlier for this molecule [Zh ang, J. Chem. Phys. 124, 084305 (2006)], more than 50 of the overtone and combination bands have been observed for cc-HOONO and cc-DOONO. Ab initio CCSD(T)/atomic natural orbital anharmonic force field calculations were used to help guide the assignments. Based on this study of the vibrational overtone transitions of cis, cis-HOONO that go as high as 8000 cm-1 and the earlier paper on the vibrational fundamentals, we conclude that the CCSD(T)/ANO anharmonic frequencies seem to correct to ±35 cm-1. The success of the theoretically predicted anharmonic frequencies {} in assigning overtone spectra of HOONO up to 8000 cm-1 suggests that the CCSD(T)/ANO method is producing a reliable potential energy surface for this reactive molecule.
- Zhang, Xu,Nimlos, Mark R.,Ellison, G. Barney,Varner, Mychel E.,Stanton, John F.
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-
- PURIFICATION OF 1,1,1,3,3,3-HEXAFLUOROISOPROPANOL
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1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) substantially free of 1,1,1-trifluoroacetone (TFA) can be separated from a mixture containing both compounds by A) catalytic reduction with hydrogen followed by fractional distillation; B) cooling to a temperature at which HFIP freezes and TFA remains liquid; C) forming a high boiling complex comprising HF and TFA followed by fractional distillation; or D) producing HF-free conditions to yield a HFIP/TFA azeotrope followed by fractional distillation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR § 1.72(b).
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Page/Page column 1
(2008/06/13)
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- CUP FOR FOOD PRODUCTS
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Useful model relates to packages, may be used as packing of liquid and viscous products, in other words ice-cream. The essence of the utility model consists in cup in the form of truncated cone 1 with bottom 2. Truncated cone 1 is made from sheet material. Bottom 2 cup is formed made from conical surface elements in the form of folds 3, bent and interconnected, perpendicular to axis of cup or at an angle to it. Fold 3 are made trapetsiidalnymi in radial direction, uniformly arranged over circumference of bottom 2 and have cross section, depicted on Figure 5 and Figure 6. On inner surface of cone 1 element is placed 6 for opening of cup, made in the form of or nitochki , or tape, Besides, conical surface is made with recesses or projections.
- Awerbuch, T. D.,Chaidukov, N. I.
-
-
- The rate constants of the two channels of the reaction of F atoms with HD in the temperature range 193-300 K
-
The rate constants for the two channels of the reaction of F atoms with HD, kF + HD and kF + DH, have been determined in the temperature range 193-300 K. The sum of rate constants kF + HD + kF + DH was determined by a competitive method and a discharge-flow-mass spectrometric technique, using the F + D2 reaction as a reference reaction. By combining the results for this sum of rate constants with published results for the rate constant kF+D2 and for the ratio of rate constants kF + HD/kF + DH, values were derived for the individual rate constants kF + HD and kF + DH. The experimental results are compared with published results of quantum mechanical calculations and of quasiclassical calculations on the Stark-Werner potential energy surface.
- Persky, Avigdor
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p. 455 - 458
(2008/10/09)
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- Single crystal growth and crystal structure of HgTeO2FOH-a layered fluorohydroxooxotellurate(IV) stabilized by weak F?OH interactions
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Light-yellow crystals of HgTeO2FOH were obtained under hydrothermal conditions by reacting stoichiometric amounts of TeO2 and HgO in diluted HF, or alternatively, by dissolution of TeO2 and Hg(NO3)2·H2O in 15 wt.% HF and subsequent slow evaporation of the solution. The crystal structure (space group Pca21, (#29), Z= 4, a = 7.8960(7), b = 6.7845(6), c = 6.8641(6) A?, 1044 structure factors, 56 parameters, R[F2 >2σ(F2)] = 0.0186, Goof = 1.007) was determined from a single crystal diffractometer data set and is made up from distorted [Hg IIO4F2(OH)] polyhedra and (Te IVO2F(OH))2- anions. These main building units form a layered assembly parallel to (0 1 0). Upon heating, HgTeO2FOH decomposes above 300°C in a two-step mechanism under formation of the mixed-valent α-HgII2TeIV/VI 2O7 and traces of HgII2Te VIO5 in the first step, and of formation of TeO 2 in the second step.
- Weil, Matthias
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p. 119 - 124
(2008/10/09)
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- Method of removing water from hydrofluorocarbon manufacturing processes
-
Disclosed are improved fluorination processes and fluorine-containing compositions which involve introducing to one or more fluorination process compositions a water reactive agent in an amount and under conditions effective to decrease the amount of water in that composition. The water reactive agent is preferably introduced to the fluorination process at a location downstream of the fluorination reaction, in amounts and under conditions effective to produce a relatively lower concentration of water in the composition, and preferably throughout the fluorination process.
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Page column 5
(2008/06/13)
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- The possibility of carbonyl fluoride as a new CVD chamber cleaning gas
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Carbonyl fluoride (COF2) has been investigated as an alternative gas for plasma-enhanced chemical vapor deposition (PECVD) chamber cleaning in order to reduce greenhouse gases emitted from the cleaning process in semiconductor manufacturing. The cleaning performance of COF2 and the environmental impact of its exhaust gases were evaluated using an experimental plasma tool. The results indicated that the cleaning performance of COF 2 was equivalent to that of conventional C2F6. Furthermore, it was confirmed that the use of COF2 would enable the reduction of global warming emissions by over 95% relative to the use of C 2F6, and thus COF2 is considered to be a promising alternative cleaning gas.
- Mitsui, Yuki,Ohira, Yutaka,Yonemura, Taisuke,Takaichi, Tsuyoshi,Sekiya, Akira,Beppu, Tatsuro
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p. G297-G301
(2008/10/09)
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- Cooperative radiative and nonradiative effects in K2NaScF6 codoped with V3+ and Er3+.
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K2NaScF6 crystals codoped with V3+ and Er3+ exhibit some novel cooperative near-IR to visible upconversion processes at cryogenic temperatures. V3+ mainly acts as a broadband sensitizer. The V3+ 3T1g --> 3T2g excitation between 13,500 and 15,500 cm(-1), after fast relaxation to V3+ 1T2g, can be transferred to Er3+ 4I(11/2), and then upconversion takes place. Four upconversion mechanisms are identified and characterized. For narrow-band laser excitation the overall efficiency of the upconversion processes is low. However, at 12 K for broadband excitation, such as in a lamp, between 12,000 and 14,500 cm(-1) the number of emitted visible photons is roughly doubled by codoping V3+ in addition to Er3+. Copyright 2004 American Institute of Physics
- Reinhard, Christine,Kramer, Karl,Biner, Daniel A,Gudel, Hans U
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p. 3374 - 3380
(2007/10/03)
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- Rovibrational and dynamical properties of the hydrogen bonded complex (CH2)2S-HF: A combined free jet, cell, and neon matrix-Fourier transform infrared study
-
The infrared study of the rovibrational and dynamical properties of the hydrogen bonded complex (CH2)2S-HF dimer was analyzed. It was observed that the combination of controlled temperature effects over a range of 40-250 K and a sophisticated band contour simulation program allowed the separation of homogeneous and inhomogeneous contributions. It was also observed that with the strengthening of the hydrogen bond upon vibrational excitation of HF, the sign of the coupling constants remained consistent. It was found that effective linewidth provides a lower bound for the predissociation lifetime of 10 ps.
- Asselin,Goubet,Lewerenz,Soulard,Perchard
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p. 5241 - 5252
(2008/01/27)
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- Fourier-transform infrared spectroscopy tor quantification of hydrogen fluoride in sulfur hexafluoride decomposed by partial discharges and sparks
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Hydrogen fluoride has been measured by infrared spectroscopy after SF6 decomposition by either electric partial discharges or sparking. Reference standard spectra necessary for quantification were calculated using the HITRAN96 data base. It is shown that the pressure broadening functions as tabulated for atmospheric conditions, are also applicable for SF6 as matrix gas. Since a strong J-quantum number dependence exists for pressure broadening of the individual HF-lines, the folding effects for the spectra based on a sinc2-instrumental line shape function of the FT-IR-spectrometer as used in this study lead to significantly different line dependent deviations from the desired linear Beer law approach. The linearity range of the maximum line absorbances in dependence of the trace volume mixing ratio was studied for a spectral resolution of 0.5 cm-1, which is much larger than the true line halfwidths found for an SF6 pressure close to 100 kPa. Quantitative results are reported for spectra obtained at optical pathlength of 10 cm and partial HF pressures up to 40 Pa using least-squares fitting and several HITRAN96-derived standard spectra. Furthermore, results from multivariate partial least-squares calibration are presented with a standard error of prediction of 0.2 Pa.
- Heise,Kurte
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p. 555 - 559
(2007/10/03)
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- Pyrohydrolysis of FeF2 and FeF3
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The pyrohydrolysis of iron di- and trifluoride has been studied. Intermediates have been separated out and analyzed. The rate constants and apparent activation energies for reactions involved have been calculated. Preparation conditions for pure FeF2 are reported. The heating behavior of this compound in an oxygen stream and in steam fed with an argon or air stream has been studied; reactions involved are described.
- Mel'nichenko,Krysenko,Epov
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p. 1399 - 1404
(2008/10/08)
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- Phase equilibria in the system silicofluoric acid-tris-(oxymethyl) aminomethane-water at 25°C
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The interaction in the silicofluoric acid-tris(oxymethyl)aminomethane (TRIS)-H2O system has been studied at 25°C by the isothermal solubility method. A new compound 2TRIS·H2SiF6 has been found and characterized by elemental analysis, IR and mass spectroscopy, and thermogravimetry. The compound solubility along the crystallization curve varies within 22.28-47.94 wt %.
- Gel'mbol'dt,Gavrilova,Sokhranenko,Ennan
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p. 1431 - 1433
(2008/10/08)
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