76-12-0Relevant articles and documents
High surface area chromium(III)fluoride – Preparation and some properties
Tav?ar, Ga?per,Skapin, Toma?
, p. 81 - 89 (2019/05/14)
Reaction of hydrated hydrazinium fluorochromate(III), [N2H6][CrF5]·H2O, with fluorine (F2)in anhydrous hydrogen fluoride (aHF)medium at room temperature yields completely amorphous CrF3-based materials with exceptionally high specific surface areas of 180–420 m2 g?1 (HS-CrF3). The stepwise reaction starts with the oxidative decomposition of the cationic part of the precursor with F2 that gives a CrF3 intermediate with low surface area. In the following step, part of Cr3+ is oxidized to Cr>3+, and in the presence of residual H2O/[H3O]+ species Cr>3+ fluoride oxides are formed. Formation of volatile chromium compounds, mainly CrO2F2, is apparently the key step in HS-CrF3 formation. Removal of these components from the final product reduces the oxygen content, and generates microporosity. The HS-CrF3 materials are completely amorphous with a bulk composition that is close to stoichiometric CrF3. Small amounts of Cr>3+ and oxygen in the final product very likely originate from the retained non-volatile CrOF3. The HS-CrF3 materials are Lewis acids and exhibit a high reactivity towards chlorofluorocarbons (CFCs)evidenced by substantial F/Cl exchange between CFCs and the solid fluoride. High reactivity of these new materials can be ascribed to their nanoscopic nature, exceptionally high surface area, and low levels of impurities. As such, they represent an interesting new class of benchmark fluoride materials applicable in fluorocarbon chemistry.
PROCESS FOR THE SYNTHESIS OF PERFLUOROBUTADIENE
-
Page/Page column 13, (2009/09/04)
Process for preparing perfluoro-1,3-butadiene, comprising the following steps : A) preparation of fluoro-halo-butanes of formula : CF2 YI-CFYIICFYIICF2 YI (V) in which YI and YII which may be identical or different, may be H, C1 or Br, with the condition that YI and YII are not simultaneously hydrogen; starting with a chloroolefin having the formula : CY'Y = CY'C1 (II) in which Y, Y', Y', which may be identical or different, are H, C1 or Br, with the condition that Y, Y', Y' are not simultaneously hydrogen; and performing the following steps : - a fluorodimerization, and - a fluorination with elemental fluorine, the order of the two steps also possibly being inverted, - a dehalogenation or dehydrohalogenation step being performed between the two steps, B) dehalogenation or dehydrohalogenation of the fluoro-halo compounds of formula (V) to give the compound perfluoro-1,3-butadiene.
Process for preparing fluorohalogenethers
-
Page/Page column 5, (2008/06/13)
A process for preparing perfluorovinylethers having general formula: [in-line-formulae]RfO—CF═CF2 ??(IA)[/in-line-formulae] wherein Rf is a C1-C3 alkyl perfluorinated substituent; comprising the following steps: 1a) fluorination with fluorine of olefins of formula: [in-line-formulae]CY″Y═CY′Cl ??(II)[/in-line-formulae]wherein Y, Y′ and Y″, equal to or different from each other, are H, Cl, Br, with the proviso that Y, Y′ and Y″ are not contemporaneously hydrogen; and obtainment of fluorohalogencarbons of formula: [in-line-formulae]FCY″Y—CY′ClF ??(III)[/in-line-formulae]wherein Y, Y′ and Y″ are as above; 2a) dehalogenation or dehydrohalogenation of the fluorohalogencarbons (III) and obtainment of fluorohalogen olefins of formula: [in-line-formulae]FCYI═CYIIF ??(IV)[/in-line-formulae]wherein YI and YII, equal to or different from each other, have the meaning of H, Cl, Br with the proviso that YI and YII are not both H; 3a) reaction between a hypofluorite of formula RfOF and a fluorohalogenolefin (IV), obtaining the fluorohalogenethers of formula: [in-line-formulae]RfO—CFYI—CF2YII ??(I)[/in-line-formulae]wherein YI, YII, equal to or different from each other, are Cl, Br, H with the proviso that YI and YII cannot be contemporaneously equal to H; 4a) dehalogenation or dehydrohalogenation of the compounds (I) and obtainment of the perfluorovinylethers (IA).
