ChemInform Abstract: Aluminum(III) Fluoride Originating from Decomposition of Hydrazinium Fluoroaluminate(III) under Oxidative Conditions: Syntheses, X‐Ray Photoelectron Spectroscopy and Some Catalytic Reactions.

Abstract

AlF3 is prepared by oxidative (F2) decomposition of [N2H6][AlF5] under gas-solid conditions and in the presence of liquid anhydrous HF. The samples are characterized by specific surface area measurements, powder XRD, XPS, and IR spectroscopy. Products prepared under gas-solid conditions exhibit small BET areas, whereas the products obtained in the presence of liquid HF have high BET areas. Some high BET samples show catalytic behavior towards isomerization of 1,1,2-trichlorotrifluoroethane and subsequent dismutations at moderate temperatures and towards room temperature dehydrochlorination of tBuCl. Catalytic activity is inhibited by surface hydroxyl groups but is improved by prior fluorination of the surface with CCl2F2. The presence of ammonium fluoroaluminate, a byproduct of the decomposition process, also inhibits catalysis. The decomposition of [N2H6][AlF5] in the presence of F2 and HF is a viable alternative route to the production of high surface area AlF3 providing the post treatment is successful in removing ammonium salts. -(SKAPIN*, T.; MAZEJ, Z.; MAKAROWICZ, A.; JESIH, A.; NICKKHO-AMIRY, M.; SCHROEDER, S. L. M.; WEIHER, N.; ZEMVA, B.; WINFIELD, J. M.; J. Fluorine Chem. 132 (2011) 10, 703-712, http://dx.

Combustion Synthesis of Amorphous Al and Cr Composite as the Catalyst for Dehydrofluorination of 1,1-Difluoroethane

“…They are attributed to 6-fold (Al VI ), 5-fold (Al V ), and 4-fold coordination (Al IV ) of aluminum, respectively. 41 Although a 19 F MAS NMR spectrum (Figure S2) was recorded for pretreated Al catalyst and no obvious difference is noted between Al catalyst and CA1 catalyst, it indicates that only trace amounts of alumina were fluorinated during pretreatment over Al catalyst. Clearly, doping of Cr facilitates the fluorination of alumina forming AlF 6 octahedra.…”

“…The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.iecr.8b02915. Details of catalyst characterization, tables of surface area, porosity, acidity, and elemental composition of catalysts, XRD spectra of spent catalysts, 19 F MAS NMR spectra, N 2 adsorption−desorption isotherms, conversion of CFC-12 for the Cl/F exchange reaction of CFC-12 as a function of Cr/Al in the catalysts, XPS spectra, surface area dependence of reaction rate, and total acidic site and strong acidic site dependence of reaction rate (PDF).…”

“…XRD (X-ray diffraction), EPR (electron paramagnetic resonance), solid state NMR of 19 F and 27 Al, and SERS (surface-enhanced Raman scattering) of Raman were adopted to explore the structures of catalysts.…”