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Fluorine pentoxide

Fluorides. Tantalum pentafluoride [7783-71-3] TaF, (mp = 96.8° C, bp = 229.5° C) is used in petrochemistry as an isomerization and alkalation catalyst. In addition, the fluoride can be utilized as a fluorination catalyst for the production of fluorinated hydrocarbons. The pentafluoride is produced by the direct fluorination of tantalum metal or by reacting anhydrous hydrogen fluoride with the corresponding pentoxide or oxychloride in the presence of a suitable dehydrating agent (71). The ability of TaF to act as a fluoride ion acceptor in anhydrous HF has been used in the preparation of salts of the AsH, H S, and PH ions (72). The oxyfluorides TaOF [20263-47-2] and Ta02F [13597-27-8] do not find any industrial appHcation. [Pg.332]

More complicated are fluorination reactions of phosphorus pentoxide with NH F 34) and NaHp2 (55) yet they are suited for the preparation of fluorophosphates on large scale ... [Pg.60]

Conversion of the separated fluorides into the corresponding oxides is effected by boiling with concentrated sulphuric acid until free from fluorine, and then hydrolysing the product by boiling with water. Alternatively, the hydrated acids are precipitated by the addition of ammonia to the solutions of the double fluorides.4 Niobium pentoxide, Nbg05, or tantalum pentoxide, TaaOs, is obtained on ignition of the precipitated hydrate. [Pg.129]

Niobium Pentafluoride, NbFs, is the only known compound of niobium and fluorine, and even this cannot be obtained in the free state by a wet method because of the extreme readiness with which it hydrolyses. Niobium pentoxide dissolves readily in hydrofluoric acid, but evaporation of the solution leaves a residue of the unchanged oxide. Niobium pentafluoride has been prepared synthetically 1 by passing dry fluorine over the gently heated metal contained in a boat in a platinum tube. The product is freed from platinum tetrafluoride, a little of which is formed at the same time, by distillation in vacuo at 100° to 110° . An alternative method consists in treating niobium pentachloride with anhydrous hydrogen fluoride in a freezing mixture and purifying by redistillation.3... [Pg.143]

Double Fluorides of Niobium Pentafluoride.—Niobium pentafluoride shows a strong tendency to form stable double fluorides with the fluorides of other metals. These are conveniently prepared by the action of carbonates of the metals on solutions of niobium pentoxide in a large excess of hydrofluoric add, or by the addition of a large excess of hydrofluoric acid to solutions of the oxyfluorides of the metals. In the absence of excess of hydrofluoric add hydrolysis takes place as usual with the formation of niobium oxytrifluoride, NbOF3. The precipitation of these double fluorides indicates the probable existence in solution of niobium pentafluoride stability is imparted by the formation of complex anions containing several fluorine atoms. [Pg.144]

NaNC>3 and cone. H2SC>4 gave 5-chloro I-nitrobenzo[2,l,3]selenadiazole 142 in 90% yield (Equation 7) <2004RJC428>. An improved method for nitration of fluorine-substituted benzo[2,l,3]selenadiazoles was also reported. Treatment of a variety of benzo[2,l,3]selenadiazoles with commercially available 90% nitric acid dissolved in a mixture of methanesulfonic acid and phosphorus pentoxide at room temperature gave 4-nitrobenzo[2,l,3]sclc-nadiazoles in 81-94% yield <2004JHC1023>. The obtained 2,1,3-benzoselenadiazoles were used as precursors to o-phenylenediamines (see Section 6.12.5.8). [Pg.544]

Phosphorus pentoxide cannot be oxidised farther by ordinary oxidising agents, except to compounds of the peracid type. The oxygen is displaced by metathesis as just shown, but not by anhydrous halogens, except fluorine, which at a dull red heat gives PFS and POFj.3... [Pg.134]

Explosive reaction with sodium -I-methanol or sodium methoxide + methanol. Mixtures with sodium or potassium are impact-sensitive explosives. Reacts violently with acetone + alkah (e.g., sodium hydroxide, potassium hydroxide, or calcium hydroxide), Al, disilane, Li, Mg, methanol + alkah, nitrogen tetroxide, perchloric acid + phosphorus pentoxide, potassium-tert-butoxide, sodium methylate, NaK. Incompatible with dinitrogen tetraoxide, fluorine, metals, or trhsopropylphosphine. Nonflammable. When heated to decomposition it emits toxic fumes of CT. [Pg.332]

The preparation of fluorinated acid anhydrides can be done by simple methods Phosphorus pentoxide removes a molecular equivalent of water from trifluoroacetic acid and tnfluoromethanesulfomc acid and forms the mixed anhydride [5J] (equation 53)... [Pg.904]

Fluorine forms the pentafluoride, CbFs, by the action of HF op the pentoxide. Itns known only in solution, but forms double salts which are more... [Pg.233]

Of the halogens, only the strongly oxidizing fluorine produces a pentahalide of vanadium, and the other vanadium(V) compounds are based on the oxohalides and the pentoxide. The pentoxide also gives rise to the complicated but characteristic aqueous chemistry of the polymerized vanadates (isopolyvanadates) which anticipates the even more extensive chemistry of the poly molybdates and poly tungstates this is only incompletely mirrored by niobium and tantalum. [Pg.979]

ARSENIOUS ACID or ARSENIOUS OXIDE or ARSENITE (1327-53-3) AsjOj Noncombustible solid. Reacts, possibly violently, with acids, aluminum, aluminum chloride, chlorine trifluoride, chromic oxide, fluorine, fluorides, halogens, hydrogen fluoride, mercury, oxygen fluoride, phosphorus pentoxide, rubidium acetylide, sodium chlorate, sodium hydroxide, sulfuric... [Pg.98]

SODIUM BICARBONATE (497-19-8) CHNaOj Noncombustible solid. Aqueous solution is a strong base. Violent reaction with acids evolving carbon dioxide. Violent reaction with finely divided aluminum, fluorine, lithium. Incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, nitrates, phenols, phosphorus pentoxide, 2,4,6-trinitrotoluene. Forms explosive material with 2,4,5-trinitrotoluene and increases the thermal sensitivity of 2,4,6-trinitrotoluene (TNT) by decreasing the tenqjerature of explosion from 566°F/297°C to 424°F/218°C. Attacks metals. Thermal decomposition at 228°F/109°C, releasing oxides of carbon. [Pg.951]


See other pages where Fluorine pentoxide is mentioned: [Pg.316]    [Pg.979]    [Pg.910]    [Pg.332]    [Pg.12]    [Pg.5]    [Pg.177]    [Pg.142]    [Pg.612]    [Pg.944]    [Pg.963]    [Pg.995]    [Pg.257]    [Pg.753]    [Pg.9]    [Pg.3]    [Pg.370]    [Pg.152]    [Pg.12]    [Pg.397]    [Pg.8]    [Pg.79]    [Pg.85]    [Pg.96]    [Pg.97]    [Pg.98]    [Pg.99]    [Pg.153]    [Pg.203]    [Pg.232]    [Pg.233]    [Pg.409]    [Pg.557]    [Pg.560]    [Pg.835]    [Pg.871]    [Pg.940]   
See also in sourсe #XX -- [ Pg.12 ]




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