Carbonyl fluoride, from

A schematic diagram of the apparatus used for preparing carbonyl fluoride from carbon monoxide and silver(II) fluoride is shown in Fig. 17. Cylinders of helium and carbon monoxide are connected through flowmeters and a pressure-release device to the copper reaction tube (47 in. long, 1-J in. diameter). A smaller copper vessel containing sodium fluoride pellets is connected with copper tubing and rubber fit-... 

Fig. 17. Schematic diagram of the apparatus used for preparing carbonyl fluoride from carbon monoxide and silver(II) fluoride.

Carbonyl fluoride, COF2, and oxygen difluoride react in the presence of cesium fluoride catalyst to give bis(trifluorylmethyl)trioxide [1718-18-9] CF OOOCF (31). CF OOF has been isolated from the reaction in the presence of excess OF2 (32). 

Uses. Besides polymerizing TFE to various types of high PTEE homopolymer, TEE is copolymerized with hexafluoropropylene (29), ethylene (30), perfluorinated ether (31), isobutylene (32), propylene (33), and in some cases it is used as a termonomer (34). It is used to prepare low molecular weight polyfluorocarbons (35) and carbonyl fluoride (36), as well as to form PTEE m situ on metal surfaces (37). Hexafluoropropylene [116-15-4] (38,39), perfluorinated ethers, and other oligomers are prepared from TEE. 

In addition, fluonne [97, 98], trifluoromethyl hypofluorite [99, 100], bisftri-fluoromethyOperoxide [100, 101], trifluoromethyl disulfide [100]. and xenon difluoride [102, lOi, 104] react with phosphines to give the corresponding diflu-orophosphoranes in yields ranging from 25% to near quantitative. Phosphites are fluorinated by carbonyl fluoride [95, 96] or 2-hydroperfIuoropropyl azide [f05J (equation 15). 

The decomposition products, up to a temperature of 500°C, are principally the monomer, tetrafluoroethylene, but also include perfluoropropene, other perfluro compounds containing four or five carbon atoms, and an unidentified particulate waxy fume. From 500°C to 800°C, the pyrolysis product is carbonyl fluoride, which can hydrolyze to form HE and CO2. 

Elemental composition C 18.19%, F 57.57%, O 24.24%. Carbonyl fluoride may be analyzed by FTIR, GC or GC/MS. For the GC analysis, it may be transported with the carrier gas helium from the reaction vessel into a cryo-genically cooled injector port, then thermally desorbed and analysed by FID. The system should be free of moisture. The characteristic ions for mass spectroscopic identification are 66, 26, and 40. 

The HF-pyridine reagent is an effective complement to di-methylaminosulfur trifluoride (DAST) reagent6 in the preparation of alkyl fluorides from alcohols. DAST is also useful for the conversion of carbonyl groups to difluoromethylene functions. The... 

From 2, 3 -bis-0-(tert-butyldimethylsilyl)-5 -deoxy-5-fluorocytidine and n-pentylchloroformate in dichloromethane and pyridine may be obtained 2, 3 -bis-0-(tert-butyldimethylsilyl)-5 -deoxy-5-fluoro-N4-((pentyloxy)carbonyl) cytidine.From 2, 3 -bis-0-(tert-butyldimethylsilyl)-5 -deoxy-5-fluoro-N4-((pentyloxy)carbonyl)cytidineand tetrabutylammonium fluoride in tetrahydrofuran at room temperature for 2 hours may be prepared the product which by hydrolyses may be converted to 5-deoxy-5-fluoro-N4-((pentyloxy)carbonyl)cytidine. Purification of the product may be carried out by silica gel chromatography (using dichloromethane methanol = 20 1 as an eluent). 

Yields of carbonyl fluoride obtained by this method range from 70 to 85%. The major contaminant in the frozen product is carbon dioxide. This substance may be present as an impurity in the carbon monoxide or may result from hydrolysis of carbonyl fluoride by traces of moisture in the apparatus. Carbonyl fluoride better than 99% pure is obtained if commercial carbon monoxide is purified before the reaction. ... 

Perfluorodimethyl peroxide, formation of, from carbonyl fluoride, 6 157... 

In the carbonyl compounds FC(0)Y the C—F bond distances show a strong dependence on the substituent X and shorten from 136.2(2) pm in acetyl fluoride (Y = Me) to 131.6(1) pm carbonyl fluoride (Y = F). In formyl fluoride (Y = H) and carbonyl chloride fluoride (Y = Cl) the C—F bond lengths are intermediate. When CF2 groups are double-bonded to C, O, S or Se, the C—F bond distances are remarkably constant and range only from 131.5 to 131.9 pm. Such bond lengths, however, are shorter by ca 1.5 pm in compounds with C=N double bonds, such as methanimine or 2,3-diaza-l, 3-butadiene. In both compounds only mean values for the C—F bond distances can be derived from the ED experiments. Ab initio calculations for perfluoromethanimine predict that the C—F bond trans to N—F is longer by 0.4 pm than the cis bond. 

Reactions with fluoride ion With the exception of CF3OH (see the next section), fluorinated alcohols of the type RpCF20H are not known [124] but complexes of K, Rb, Cs, Ag or (C2H5)4N+ fluorides with hexafluoroacetone have been isolated [125, 126], following from the earlier isolation of some similar complexes with carbonyl fluoride [127]. These complexes have been reasonably formulated as fluorinated alkox-ides (Figure 8.27), but the use of these salts in synthesis is often difficult because the complexes may also act as fluoride-ion donors [128]. 

In operation, the gases enter at diametrically opposite sides of the cylindrical combustion chamber. It is here that much carbonyl fluoride is formed and much heat is liberated. If flow rates are too high, the heat of the reaction may ignite copper in contact with fluorine. The capacity of the apparatus to produce trifluoromethyl hypo-fluorite appears to be limited by the rate of removal of heat from this reactor. A mixing chamber made from copper, nickel. Monel metal, or other fluorine-resistant metal should be satisfactory, provided that adequate provision is made for removal of heat. Suitable rates of flow for the apparatus described are fluorine, about 5 l./hour carbon monoxide, about 2 to 2.3 l./hour. The limiting rates have not been established. It is important that the ratio by volume of fluorine to carbon monoxide be somewhat more than 2 1. 

Many of the carbon compounds containing both fluorine and oxygen decompose by complex mechanisms. However, the thermal decomposition of tetrafluoro-ethylene oxide is claimed to be unimolecular over the temperature range 115-140 °C, with = 5 X 10 sec and E = 31.6 kcal.mole". The products are carbonyl fluoride and perfluoroethylene plus perfluorocyclopropane (probably formed from CF2). In a pyrex glass vessel at 40-45 °C trifluoroacetylfluoride is produced by a heterogeneous process. 

These compounds may be formed directly from the metal halides by the action of CO (for example, CO and anhydrous C0I2 give Co(CO)l2) or, in the case of iron iiylirectly from the carbonyls or carbonyl hydrides. The only carbonyl fluoride which has been well characterized has the empirical formula Mo(CO)2F4 a dimeric structure with two bridging F atoms has been suggested. The compounds Pt(CO)2p8 and Rh(CO)2p3 have been described as the products of the action of... 

Carbonyl fluoride, COFj. Mol. wt. 60.01, toxic gas, b.p. —81°. Prepared from carbon monoxide and silver (II) fluoride and by introduction of liquid phosgene into a suspension of sodium fluoride in acetonitrile. Suppliers Peninsular Chem-Research, Pierce Chem. Co. 

Despite the possibly unfavourable thermodynamics for phosgene polymerization, it may be possible to prepare polyphosgene by alternative routes. Poly(carbonyl fluoride), for example, has been prepared from the reaction of tetrafluoroethene with trioxygen (ozone) (see Chapter 13). Alternatively, the co-polymerisation of phosgene with, for example, alkenes may be worthy of investigation [ICI94]. 

Perhaps the most likely immediate commercial application of carbonyl fluoride, however, arises from its spectroscopic properties. Irradiation of mixtures of COF, and H, (or D,), over a wide pressure range and at ambient temperature, with the multiline output of a continuous wave CO, laser, results in the generation of excited state HF (DF) which lases [1387]. Energy transfer from the R, line (970 cm" ) of CO, (which is close in energy to the c, band of COF,) causes the dissociation of the COF, to CO and two excited state fluorine atoms which subsequentiy react with the dihydrogen (or dideuterium). However, COF, itself has been found to effect rapid vibrational de-excitation of HF [239], an observation that suggests that the COF,/H, route to the HF laser may be of limited practicality. 

Synthesis of carbonyl difluoride from carbonyl chloride fluoride... 

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