Fluorine pentafluoride

Iodine Acetaldehyde, acetylene, aluminum, ammonia (aqueous or anhydrous), antimony, bromine pentafluoride, carbides, cesium oxide, chlorine, ethanol, fluorine, formamide, lithium, magnesium, phosphorus, pyridine, silver azide, sulfur trioxide... 

Sihcon and boron bum ia fluorine forming siUcon tetrafluoride [7783-61-17, SiF, and boron trifluoride [7637-07-2] respectively. Selenium and tellurium form hexafluorides, whereas phosphoms forms tri- or pentafluorides. Fluorine reacts with the other halogens to form eight interhalogen compounds (see Fluorine compounds, inorganic-halogens). 

Fluorine reacts with the halogens and antimony to produce several compounds of commercial importance antimony pentafluoride [7783-70-2J, bromine trifluoride [7787-71 chlorine trifluoride [7790-91 -2J, and iodine pentafluoride [7783-66-6J. Chlorine trifluoride is used in the processing of UF (see Uraniumand uranium compounds). Bromine trifluoride is used in chemical cutting by the oil well industry (see Petroleum). Antimony and iodine pentafluorides are used as selective fluorinating agents to produce fluorochemical intermediates (see Fluorine compounds, inorganic). 

Arsenic pentafluoride can be prepared by reaction of fluorine and arsenic trifluoride or arsenic from the reaction of NF O and As (16) from the reaction of Ca(FS02)2 and H AsO (17) or by reaction of alkaH metal or alkaline-earth metal fluorides or fluorosulfonates with H AsO or H2ASO2F (18). 

The halogen fluorides are binary compounds of bromine, chlorine, and iodine with fluorine. Of the eight known compounds, only bromine trifluoride, chlorine trifluoride, and iodine pentafluoride have been of commercial importance. Properties and appHcations have been reviewed (1 7) as have the reactions with organic compounds (8). Reviews covering the methods of preparation, properties, and analytical chemistry of the halogen fluorides are also available (9). 

The halogen fluorides are best prepared by the reaction of fluorine with the corresponding halogen. These compounds are powerful oxidising agents chlorine trifluoride approaches the reactivity of fluorine. In descending order of reactivity the halogen fluorides are chlorine pentafluoride [13637-63-3] 1 5 chlorine trifluoride [7790-91-2] 3 bromine pentafluoride [7789-30-2], BrF iodine heptafluoride [16921 -96-3], chlorine... 

Iodine Pentafluoride. Iodine pentafluoride is produced by the reaction of iodine and fluorine. Because iodine has a high melting poiat, the reaction is either performed ia a solvent or the reaction is maintained at a temperature where the iodine is Hquid. In a continuous process usiug a solvent (104), ca 1% I2 is dissolved iu IF and passed to a reactor where it is contacted with F2 gas. The IF is continuously discharged from the reactor where a small portion is taken off as product and the larger portion of the stream is recycled. 

Iodine pentafluoride is an easily storable Hquid source of fluorine having Httie of the hazards associated with other fluorine sources. It is used as a selective fluorinating agent for organic compounds. For example, it adds iodine and fluorine to tetrafluoroethylene in a commercial process to produce a usefiil telomer (124). 

Three other binary compounds of molybdenum and fluorine are known to exist molybdenum trifluoride [20193-58-2] MoF, molybdenum tetrafluoride [23412-45-5] MoF, and molybdenum pentafluoride [13819-84-6] MoF. Also known are the two oxyfluorides, molybdenum dioxydifluoride [13824-57-2] M0O2F2, and molybdenum oxytetrafluoride [14459-59-7] MoOF. The use of these other compounds is limited to research appHcations. 

The only example of xenon in a fractional oxidation state, +, is the bright emerald green paramagnetic dixenon cation, Xe [12185-20-5]. Mixtures of xenon and fluorine gases react spontaneously with tiquid antimony pentafluoride in the dark to form solutions of XeF+ Sb2 F, in which Xe is formed as an iatermediate product that is subsequently oxidized by fluorine to the XeF+ cation (83). Spectroscopic studies have shown that xenon is oxidized at room temperature by solutions of XeF+ ia SbF solvent to give the XE cation (84). 

Niobium Penta.fIuoride, Niobium pentafluoride is prepared best by direct fluorination of the metal with either fluorine or anhydrous hydrofluoric acid at 250—300°C. The volatile NbF is condensed in a pyrex or quartz cold trap, from which it can be vacuum-sublimed at 120°C to yield colorless monoclinic crystals. It is very hygroscopic and reacts vigorously with water to give a clear solution of hydrofluoric acid and H2NbOF ... 

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. 

Antimony pentafluoride may be prepared by fluorination of SbF or by treatment of SbCl with HF. In the latter method the fifth chlorine is removed with difficulty failure to remove the chlorine completely results in contamination of the distilled SbF with Sb(III) (27). 

Antimony pentafluoride is a strong Lewis acid and a good oxidizing and fluorinating agent. Its behavior as a Lewis acid leads to the formation of numerous simple and complex adducts. It reacts vigorously with water to form a clear solution from which antimony pentafluoride dihydrate [65277-49-8], SbF 2H2O, may be isolated. This is probably not a tme hydrate, but may well be better formulated as [H O] [SbF OH]. 

The principal use of antimony pentafluoride is as a fluorinating agent. It readily replaces all chlorines with fluorine in organic compounds, and it fluorinates double bonds and aromatic rings. 

Bismuth Penta.fIuoride, Bismuth(V) fluoride consists of long white needles that have been shown to have the same stmcture as the body-centered, tetragonal a-polymorph of uranium hexafluoride. The density of the soHd is 5.4 g/mL at 25°C. The soHd consists of infinite chains of trans-bridged BiF polyhedra dimers and trimers are present in the vapor phase (22). Bismuth pentafluoride may be prepared by the fluorination of BiF or... 

Bismuth pentafluoride is an active fluorinating agent. It reacts explosively with water to form ozone, oxygen difluoride, and a voluminous chocolate-brown precipitate, possibly a hydrated bismuth(V) oxyfluoride. A similar brown precipitate is observed when the white soHd compound bismuth oxytrifluoride [66172-91 -6] BiOF, is hydrolyzed. Upon standing, the chocolate-brown precipitate slowly undergoes reduction to yield a white bismuth(Ill) compound. At room temperature BiF reacts vigorously with iodine or sulfur above 50°C it converts paraffin oil to fluorocarbons at 150°C it fluorinates uranium tetrafluoride to uranium pentafluoride and at 180°C it converts Br2 to bromine trifluoride, BrF, and bromine pentafluoride, BrF, and chlorine to chlorine fluoride, GIF. It apparently does not react with dry oxygen. 

Bromine monofluoride [13863-59-7], BrF, can be prepared by the direct reaction of Br2 and F2, but because it readily disproportionates it has never been prepared in pure form (57). However, BrF can be prepared in situ by the reaction of Br2 with AgF in benzene (58) or by the reaction of A/-bromoacetamide and HF in ether (59). BrF adds to simple alkenes at room temperature to give products of trans-addition. Bromine trifluoride [7787-71-5], BrF, can be formed from gaseous fluorine and Hquid bromine (60). Bromine pentafluoride [7789-30-2], BrF, is formed from the reaction of BrF vapor with gaseous fluorine at 200°C (60). The tri- and pentafluorides are commercially available. As strong fluorinating agents they are useful in... 

Fluorination and iodination reactions are used relatively littie in dye synthesis. Fluorinated species include the trifluoromethyl group, which can be obtained from the trichi oromethyl group by the action of hydrogen fluoride or antimony pentafluoride, and various fluorotria2iQyl and pyrimidyl reactive systems for reactive dyes, eg, Cibacron F dyes. 

Grown Ethers. Ethylene oxide forms cycHc oligomers (crown ethers) in the presence of fluorinated Lewis acids such as boron tritiuoride, phosphoms pentafluoride, or antimony pentafluoride. Hydrogen fluoride is the preferred catalyst (47). The presence of BF , PF , or SbF salts of alkah, alkaline earth, or transition metals directs the oligomerization to the cycHc tetramer, 1,4,7,10-tetraoxacyclododecane [294-93-9] (12-crown-4), pentamer, 1,4,7,10,13-pentaoxacyclopentadecane [33100-27-6] (15-crown-6), andhexamer, 1,4,7,10,13,16-hexaoxacyclooctadecane [17455-13-9]... 

Antimony trichloride, pentachloride and pentafluoride Beryllium chloride Boron trichloride Bromine Chlorine Calcium fluoride Chromic fluoride Chromous fluoride Fluorine Iodine... 

Trimethylarsine gives a 98% yield of trimethylarsine difluoride when treated with xenon difluoride [102] in fluorotrichloromelhane. and tnsfpentafluorophen-yl)arsine gives a 94% yield of tris(pentafluornphenyl)arsme difluoride after reaction with dilute fluorine in fluorotnchloromethane at 0 C [106] Other trivalent arsenic compounds have also been fluorinated with xenon difluoride [103] In addition, arsines have been oxidatively fluorinated by iodine pentafluoride [107] or electrochemically in 26-34% yield [108]... 

Xenon difluoride has been used to oxidize a number of antimony compounds [102, 109] in yields ranging from 73 to 98%. Elemental fluorine oxidized tris(pen-tafluorophenyl)stibine to tris(pentafluorophenyl)stibine difluoride in 98% yield [706]. Oxidative fluonnation of stibines has also been accomplished with iodine pentafluoride [707]. 

Addition of carbon and fluorine can also be initiated by elettraphilic attack on a/luorinated otefin under strongly acidic conditions [250, 251, 252,253 254 255] Best known are fluoroalkylations ot tetrafluoroethylene by tertiary or highly halogenated allylic or benzylic cations in the presence of antimony pentafluoride (equation 53)... 

Vinyl and phenyl mfluoromethyl groups are reactive in the presence of aluminum chloride [10] Replacement of fluorine by chlorine often occurs Polyfluori-nated trifluoromethylbenzenes form reactive a,a-difluorobenzyl cations in antimony pentafluoride [11] 1 Phenylperfluoropropene cyclizes in aluminum chloride to afford 1,1,3-trichloro 2 fluoroindene [10] (equation 10) The reaction IS hypothesized to proceed via an allylic carbocation, whose fluoride atoms undergo halogen exchange... 

The stabilized fluorinated allylic cation, generated from cis- or trans-l-(p-methoxyphenyl)pentafluoropropene and antimony pentafluoride in sulfur dioxide, is solvolyzed by methanol to methyl 2-(p-methoxyphenyl)difluoroacrylate [36] (equation 37)... 

The reactions of some fluorinated ethers may result in the elimination of alkyl fluorides In the case of 2-methoxyperfluoro-2-butene, treatment with antimony pentafluoride gives perfluoro-3-buten-2-one and methylfluoride [107] By reacting 2-chloro-l,l,2-trifluorodiethyl ether with boron trifluoride etherate or with aluminum chloride, chlorofluoroacetyl fluoride can be obtained with the elimination of ethyl fluonde [108] (equations 76 and 77)... 

Fluonnation and skeletal transformation of fluorinated cycloalkanes occurs in the reaction with antimony pentafluoride at high temperature [777] In the case of perfluorinated benzocyclobutanes, an unexpected alicyclic ring cleavage has been observed Perfluorinated alkyl benzocyclobutanes, when treated with antimony pentafluoride, ean be converted to perfluorinated styrenes and then transformed to perfluorinated indans [77S, 779]... 

Ti, Zr, Hf, Th, U and the pentafluorides of Nb and Ta). However, many higher fluorides require the use of a more aggressive fluorinating agent or even F2 itself. Typical of the fluorides prepared by oxidative fluorination with F2 are ... 

Transition metal pentafluorides and related compounds. R. D. Peacock, Adv. Fluorine Chem., 1972,7,113-145(172). 

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