Superacid System Research Articles

Niobium(V) and tantalum(V) fluoride derivatives of fluorosulfuric and trifluoromethylsulfuric acids

The syntheses and characterizations of three niobium(V)- and tantalum(V) fluoro derivatives of the sulfonic acids HSO 3F and HSO 3CF 3 are described. All are white, solid, seemingly polymeric sulfonato bridged materials, which are of interest as Lewis acids in super acid systems. NbF 2(SO 3F) 3 forms as a byproduct in the oxidation of niobium by bis(fluorosulfuryl)peroxide in HSO 3F as a polymeric solid. TaF 4(SO 3CF 3) results from the addition of triflic acid, HSO 3CF 3, to Ta(SO 3F) 5 dissolved in HSO 3F, while TaF 4(SO 3F) forms in a ligand redistribution reaction of Ta(SO 3F) 5 with a four-fold amount of TaF 5 in HSO 3F as solvent. Infrared and Raman spectra of the compounds are reported.

Darstellung und spektroskopische Charakterisierung von primären und sekundären Sulfoniumsalzen [1] / Preparation and Spectroscopic Characterization of Primary and Secondary Sulfonium Salts [1

The preparation and spectroscopic characterization of the sulfonium salts R2SH+MF6- and RSH2 +MF6- (R = CH3, t-C4H9; M = As, Sb) is reported. The compounds are synthesized by protonation of the corresponding sulfanes in the superacid system HF/MF5.

Superacid-induced ring-opening reactions of fluorinated heterocycles

HF/AsF5 and HF/SbF5 superacid mixtures react with fluorinated small-ring heterocycles such as 1,2-oxazetidines and oxetanes with consequent addition of HF to give alcohol and amine ring-opened products in high yield. Excess HF serves as solvent and reactant. Ring compounds containing both nitrogen and oxygen as heteroatoms protonate predominantly on nitrogen; a case with competing O-protonation arises in the case of a chloro-substituted oxazetidine. In general, rings containing two heteroatoms retain the heteroatom–heteroatom bond and it is a carbon–heteroatom bond that opens. The resulting OH and NH functional groups are not protonated and lost in the superacid medium due to the instability of the highly fluorinated cations that would be left behind. Most of the heterocycles react at or below room temperature, although the very weakly basic 2,2-bis(trifluoromethyl)-3,3,4,4-tetrafluorooxetane requires the stronger HF/SbF5 superacid system and more severe conditions. Keywords: superacids, hydrogen fluoride, ring opening, fluorinated oxazetidines, fluorinated oxetanes.

Protonation of carboxylic acids by hydrogen bromide in dibromodifluoromethane: rates of proton exchange, relative basicities, and the acidity of HBr–CBr2F2

Ethanoic, propanoic, butanoic, 2,2-dimethylpropanoic, phenylethanoic, and benzoic acids are fully protonated by HBr–CBr2F2, and at low temperatures (<168 K) separate 1H n.m.r. signals for HBr and RCO2H2+ are observed. If the temperature is reduced even further then resolution of the two acid proton signals of the latter may be observed. Dichloroethanoic and trichloroethanoic acids are not protonated by this acid system. 2-Chloropropanoic acid may be partly protonated. Line-shape analysis of the n.m.r. spectra at low temperatures has been used to determine the rates of proton exchange between HBr and RCO2H2+, and in this way an assessment of the relative basicities of the carboxylic acids is obtained. The behaviour of HBr–CBr2F2 is compared with superacid systems.

Analytical applications of superacid dissolution of actinide and lanthanide substrates

The superacid system HF/SbF5 is extraordinarily effective for total dissolution of actinide and lanthanide ceramic oxides, fluorides, and metals. Optical or gamma spectroscopy can be used directly on the solutions. Evaporation of the HF/SbF5 solvent under vacuum leaves a residue which is easily dissolved by ordinary mineral acids. The resulting aqueous solutions are readily amenable to conventional analytical methods.

Superacid Systems on Solid Carriers

Chemie Ingenieur TechnikVolume 59, Issue 2 p. 178-179 Wissenschaftliche Forschungsarbeit Superacid Systems on Solid Carriers Prof. ass. Dr. habil. Ing. Romuald Bogoczek, Prof. ass. Dr. habil. Ing. Romuald Bogoczek Dept. of Chemical Technology in the Technological Institute of Chemical and Food Industry at the Academy of Economics, UI. Komandorska 118/120, 53-345 Wroclaw, PolandSearch for more papers by this authorDr.-Ing. Joanna Surowiec, Dr.-Ing. Joanna Surowiec Dept. of Chemical Technology in the Technological Institute of Chemical and Food Industry at the Academy of Economics, UI. Komandorska 118/120, 53-345 Wroclaw, PolandSearch for more papers by this author Prof. ass. Dr. habil. Ing. Romuald Bogoczek, Prof. ass. Dr. habil. Ing. Romuald Bogoczek Dept. of Chemical Technology in the Technological Institute of Chemical and Food Industry at the Academy of Economics, UI. Komandorska 118/120, 53-345 Wroclaw, PolandSearch for more papers by this authorDr.-Ing. Joanna Surowiec, Dr.-Ing. Joanna Surowiec Dept. of Chemical Technology in the Technological Institute of Chemical and Food Industry at the Academy of Economics, UI. Komandorska 118/120, 53-345 Wroclaw, PolandSearch for more papers by this author First published: February 1987 https://doi.org/10.1002/cite.330590236Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume59, Issue2February 1987Pages 178-179 RelatedInformation

Fluorine containing ansolvo super acids and intercalants in graphite—a common link

Ansolvo super acids and intercalants in acceptor graphite intercalation compounds (GICs) must both be excellent electron acceptors, a property most frequently encountered in coordinatively seemingly unsaturated fluorine containing compounds. Interestingly AsF 5 and SbF 5 have served in both capacities. There is a crucial difference however: the intercalation process is a red-ox reaction with the exact nature of the intercalate unclear and often subject to controversies. The acceptor ability of ansolvo super acids is directed towards anion abstraction to generate coordinatively saturated super acid anions, capable of generating and stabilizing unusual cations either in solution or in solids. The oxidative intercalation to generate the super acid anion SO 3F − in graphite, the physical properties and bonding will be discussed. Its reaction with AsF 5 and SbF 5 and the protic acids HSO 3F and HSO 3CF 3 will be described. A generally applicable, interacting ion model will be proposed to describe bonding and electron transfer. The development of SO 3X-based super acid systems in HSO 3X, with X = F or CF 3 will be developed and the preparation aimed at M(SO 3X) 4 will be discussed for a wide range of metals. Solution studies on the systems Pt(SO 3F) 4HSO 3F, Sn(SO 3CF 3) 4HSO 3CF 3 and An(SO 3F) 3HSO 3F will be described. Preparative attempts to stabilise a number of unusual cations will illustrate the effectiveness of the ansolvo super acids developed by us.

Chemistry in superacids. 6. Perfluoroalkanesulfonic acid-boron perfluoroalkanesulfonates: new superacid systems for generation of carbocations and catalysts for electrophilic transformations of hydrocarbons

Les superacides conjugues obtenus a partir de trihalogenoboranes et d'acides perfluoroalcanesulfoniques sont utiles pour la preparation de carbocations et comme catalyseurs. Leur instabilite thermique limite cependant leur emploi

Superacid coal chemistry: 1. HF:BF 3 catalysed depolymerization—ionic hydroliquefaction of coals under mild conditions

HF:BF 3:H 2 catalysed depolymerization and hydroliquefaction of coal was studied. This superacidic system was found to be extremely effective for low temperature liquefaction of coal. Illinois No. 6 coal could be solubilized in pyridine to the extent of > 90% by treating it at ≈ 105 °C for 4 h. Under somewhat more elevated temperature (150–170 °C) cyclohexane extractabilities of up to 22% and distillability of up to 28% is achieved. A hydrogen donor solvent such as isopentane is shown to improve the efficiency of the superacidic catalyst for the conversion of coal to cyclohexane soluble products.

Stability of quinone and reduced forms in hydrogen fluoride and hydrogen fluoride–antimony pentafluoride superacid systems: an electrochemical and proton nuclear magnetic resonance study

The techniques, electrochemistry and 1H n.m.r., are shown to be complementary in the study of the stability limits of benzoquinone, semiquinone, and hydroquinone and their conjugated acids at various protonation stages in the HF derived superacid system. Acidity constants are determined and conditions for the disproportionation of the semiquinone form are established. The complete potential–pH diagram in HF could be defined.

ChemInform Abstract: NUCLEAR MAGNETIC RESONANCE STUDY OF THE PROTONATION OF 2,6‐DIMETHYL‐Γ‐PYRONE AND RELATED BASES IN SUPERACID SYSTEMS

Chemischer InformationsdienstVolume 12, Issue 31 Preparative Organic Chemistry ChemInform Abstract: NUCLEAR MAGNETIC RESONANCE STUDY OF THE PROTONATION OF 2,6-DIMETHYL-Γ-PYRONE AND RELATED BASES IN SUPERACID SYSTEMS V. GOLD, V. GOLDSearch for more papers by this authorT. MAH, T. MAHSearch for more papers by this author V. GOLD, V. GOLDSearch for more papers by this authorT. MAH, T. MAHSearch for more papers by this author First published: August 4, 1981 https://doi.org/10.1002/chin.198131134AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue31August 4, 1981 RelatedInformation

Nuclear magnetic resonance study of the protonation of 2,6-dimethyl-γ-pyrone and related bases in superacid systems

1 H and 13C n.m.r. spectra indicate that 2,6-dimethyl-4H-pyran-4-one in solution in HSO3F–SbF5(1 : 1) is doubly protonated at the exocyclic oxygen atom. The sulphur and nitrogen analogues, 2,6-dimethyl-4H-thiopyran-4-one, and 2,6-dimethyl-N-methyl-4-pyridone, respectively, behave similarly. Other related compounds show 1H and 13C n.m.r. spectra in support of our interpretation.

Superacids

Superacids, although first referred to as early as 1927, were only extensively studied in the last decade. Acidities up to 10(12) times that of sulfuric acid have now been obtained. The extremely low nucleophilicity of the counterions in superacidic systems is especially useful for the preparation of stable, electron-deficient cations, particularly carbocations. Many of these cations, which were formerly detectable only in the gas phase, can now be studied in solution. Novel organic syntheses that are not possible in ordinary acidic media can also be achieved in superacids, including syntheses of economically important hydrocarbons. The unique ability of superacids to bring about hydrocarbon transformations, even to activate methane to undergo electrophilic oligocondensation, can open up new fields in chemistry.

A Study of the 1,3,5-Trialkylbenzenes with Aluminum Chloride-Hydrogen Chloride Systems

Abstract The “red-oil” complex layers of systems of 1,3,5-trialkylbenzenes (Me3B, Et3B, i-Pr3B, and s-Bu3B) with AlCl3–HCl were prepared and studied by means of 1H NMR and 13C NMR spectroscopy. The results show that the 2,4,6-trialkylbenzenium ion is evidently formed in the complex layer of the AlCl3–HCl system, much as in other super acid systems, and that those ions from i-Pr3B and s-Bu3B are substantially stable, even at room temperature. The molar ratios of i-Pr3B and s-Bu3B to HAl2Cl7 are almost 1. On the other hand, the molar ratios of Me3B and Et3B to HAl2Cl7 are 4.5 and 1.9 respectively. These two complex layers are considered to be formed by both 1,3,5-trialkylbenzene and its protonated product, and to be in a certain equilibrium state as a result of proton exchange at room temperature.

Some aspects of chemistry in strongly acidic solvent media

Abstract

Formation of Br2+, Br3+, BrOSO2F, and Br(OSO2F)3 by the oxidation of bromine with peroxydisulfuryl difluoride in solution in fluorosulfuric acid and the superacid system antimony pentafluoride-3 sulfur dioxide-fluorosulfuric acid

Formation of Br2+, Br3+, BrOSO2F, and Br(OSO2F)3 by the oxidation of bromine with peroxydisulfuryl difluoride in solution in fluorosulfuric acid and the superacid system antimony pentafluoride-3 sulfur dioxide-fluorosulfuric acid

Hammett acidity function for some super acid systems. I. Systems H2SO4-SO3, H2SO4-HSO3F, H2SO4-HSO3Cl, and H2SO4-HB(HSO4)4

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHammett acidity function for some super acid systems. I. Systems H2SO4-SO3, H2SO4-HSO3F, H2SO4-HSO3Cl, and H2SO4-HB(HSO4)4R. J. Gillespie, T. E. Peel, and E. A. RobinsonCite this: J. Am. Chem. Soc. 1971, 93, 20, 5083–5087Publication Date (Print):October 1, 1971Publication History Published online1 May 2002Published inissue 1 October 1971https://doi.org/10.1021/ja00749a021RIGHTS & PERMISSIONSArticle Views1034Altmetric-Citations101LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (535 KB) Get e-Alerts Get e-Alerts

Fluorosulfuric acid solvent system. VII. The behavior of some extremely weak bases in the superacid system fluorosulfuric acid- antimony pentafluoride-sulfur trioxide

Fluorosulfuric acid solvent system. VII. The behavior of some extremely weak bases in the superacid system fluorosulfuric acid- antimony pentafluoride-sulfur trioxide