Fluorine nitrogen-diluted

Fig. 5. Equipment foi surface treating plastic components. Parts ate loaded into one of the two lower chambers which is then evacuated to remove most of the air. This chamber is then flooded with a dilute mixture of fluorine and nitrogen which is made and stored in the upper chamber. After the treatment is completed, the fluorine mixture is pumped back up to the upper chamber for storage and the lower chamber repeatedly flooded with air and evacuated to remove any traces of fluorine gas. Two treatment chambers are cycled between the loading/unloading operation and the treatment step to increase equipment output. The fluorine—nitrogen blend may be used several times before by-products from the treatment process begin to interfere. AH waste...

Fluorination of caesium heptafluoropropoxide at —40°C with nitrogen-diluted fluorine exploded violently after 10 h. This may have been caused by ingress of moisture, formation of some pentafluoropropionyl derivative and conversion of this to pentafluoropropionyl hypofluorite, known to be explosive if suitably initiated. Other possible explosive intermediates are peroxides or peresters. 

F2N.C( NF).NF.C(NF2)2F mw 265.04, N 26.42%, FB +7.2% FB is analogous with OB, being applied hereafter to fluorinated compds wherein the F is not already on C it is calculated in the same manner, the factor 1900/mw being used instead of 1600/mw) liq, bp ca 80° mp below —130° a 50/50 mixt of the cis and trans isomers, Prepd by fluorinating biguanide sulfate with nitrogen diluted fluorine and a sodium-magnesium fluoride mixt at 0° Proposed as an oxidizer for propints. Should be treated with extreme caution. May readily detonate into CF4 and N2. Do not let vapors contact mercury Refs 1) Beil, not found 2) J.J. Hockstra,... 

Elemental fluorine, commonly diluted with an inert gas (argon, neon, nitrogen), can be used in a variety of solvents. Chlorinated hydrocarbons... 

Bromine monofluoride or iodine monofluoride can be prepared from the corresponding elements in trichlorofluoromethane at — 781 and — 45 C,2,3 respectively. The compounds are unstable and decompose at low temperatures, iodine monofluoridc at — 14 C2,3 and bromine monofluoride, in part, even at — 78 C.1 Therefore, they are used, without separation and purification, in Freon solutions at low temperatures or, most frequently, as stoichiometric mixtures bromine trifluoride/bromine and iodine pentafluoride/iodine. A solution of iodine monofluoride, obtained by bubbling nitrogen-diluted fluorine gas into a suspension of iodine in trichlorofluoromethane at — 75 C, was used for addition to alkene C = C bonds. The reaction is regioselective and in most cases obeys the Markovnikov rule.4 Iodine monofiuoride prepared in situ reacts quite efficiently with steroidal alkenes.4... 

N , N -1 )ifluoro-2,2 -bipy ri < (i n i 11 rn bis(tetrafluoroborate) 19, prepared in one pot by introducing BF3 gas into 2,2 -bipyridine at 0°C followed by fluorine gas diluted with nitrogen, was shown to be a highly reactive electrophilic fluorinating agent (Equation 5) <2003JFC173>. 

At first sight the direct fluorination of ammonia might appear to be a useful alternative method for obtaining the trifluoride, but this reaction, if uncontrolled, yields mainly nitrogen and hydrogen fluoride with only about 6% of NF3 (258). The yield is greatly improved when the fluorine is diluted with N2 and this gas is allowed to mix with ammonia in a reactor packed with copper turnings (212). Under these conditions... 

Another method used to control the high reaction enthalpy of fluorination is coating of the organic substrate as a thin film on sodium fluoride powder and reaction in a moving bed reactor with fluorine gas, diluted with nitrogen or helium. Slow, stepwise increase of the fluorine concentration also enables clean perfluori-nation of rather complex substrates [9] (Scheme 2.2). 

One of the first examples of industrial application of selective direct fluorination was the synthesis of the cytostatic 5 -fluorouracil. In the most commonly used process the precursor uracil is treated with nitrogen-diluted fluorine in hot water and the intermediate fluorohydrin is subsequently dehydrated either by heating the aqueous solution to 100 °C or with sulfuric acid [18] (Scheme 2.6.). 

Halogen monofluorides are generated by the reaction of halogens with fluorine gas diluted with nitrogen. They are strongly electrophilic becasue of their attachment to the most... 

The melt temperature of the extrudate was 210°C and the bottles were formed by inflation of the parison to 0.72 MPa in a 10°C water-chilled mold. The containers, weighing approximately 41.5 grams, had a nominal wall thickness of 0.1 cm and a surface area of 408 cm2. One-half of the containers were prepared untreated using nitrogen as the inflation gas. The other half were in situ fluorinated by the AIROPAK Process using a nitrogen-diluted fluorine as the inflation gas (Figure 1), as described by Dixon (7) and Kallish, et al (22). 

Fluorination at unactivated carbon sites. With fluorine gas (diluted with nitrogen) such a reaction in MeCN at the temperature of ice can be quite efficient. Thus, fluorocyclohexane has been obtained in 63% yield. Note that decalin is fluorinated exclusively at an angular position whereas the secondary carbon sites are attacked by 1-chloromethyl-4- fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate). 

Substitution of chlorine by, and addition of, hot and thermal F atoms o frflws-CHChCHF have been studied. A study of the rates of fluorination of vinyl fluoride, 1,1-difluoroethylene, and tetrafluoroethylene in the vapour phase using nitrogen-diluted fluorine has indicated that at 291 K the relative rates fall in the ratio 1.00 0.85 0.76, for the respective olefins. ... 

The flow of fluorine is started and as soon as the reaction has commenced, as indicated by heating of the reactor, the fluorine is diluted with an equal volume of dry nitrogen. When a good flow of product is obtained, as evidenced by copious fumes at the exit, the trap is cooled in liquid nitrogen to condense the silicon tetrafluoride and carbon tetrafluoride. The reaction is allowed to continue imtil the... 

Our typical preparation method for these perfluorodioxolane monomers and polymers is shown in Scheme 16.5 [13-18]. Commercially available methyl pyruvate and diols are used as the starting materials. The condensation product is then directly fluorinated in a fluorinated solvent such as Fluorinert FC-75 by the F2/N2 mixture. After flushing the system using nitrogen gas for 1 hour, fluorine gas diluted to 20% with nitrogen is blown into the reaction mixture at a flow rate of 240 L/h. The reaction is carried out at a temperature of around 25°C for over 20 hours. After the reaction is over, the mixture is neutralized with aqueous potassium hydroxide solution. The... 

One of the most efficient and simplest routes for the fabrication of these perfluorodioxolane monomers and polymers is shown in Scheme 4.3 [26-30]. Commercially available methyl pyruvate and diols are used as the starting materials. The condensation product is then directly fluorinated in a fluorinated solvent such as Fluorinert FC-75 (3M) with a F2/N2 mixture. After flushing the system with nitrogen gas for 1 h, fluorine gas diluted to 20% with nitrogen is blown into the reaction mixture at a flow rate of 2401/h. The reaction is carried out at approximately 25 C for over 20 h. After the reaction is complete, the mixture is neutralized with aqueous potassium hydroxide. The crude monomer is isolated upon decarboxylation of the potassium salt and then purified by fractional distillation. The fluorination process is the key step in the synthesis. The yield is as high as 75% with careful control of the fluorination temperature, and it depends on the structure of the hydrocarbon precursor. Recently, over 90% yield of the fluorination of similar compounds has been reported [31]. The polymerization of these monomers is generally carried out in bulk at 60 - 80 °C for 24-35 h using perfluorodibenzoyl peroxide as the initiator [32]. The conversion yields are 70-80%, and the polymers obtained are colorless and transparent. 

Fluorination could be achieved by fluorine radical generating compounds or fluorine gas the latter was the preferred source. Fluorine was diluted (10-25 mole%) by an inert gas like nitrogen due to the highly exothermic nature of fluorine reactions. It is also more hazardous to work with pure fluorine. Atmospheric pressure has been recommended, although pressure could be as high as ten atmospheres. The fluorination reactor was evacuated to about 0.1 atmospheres prior to starting the flow of fluorine gas. 

Manufacture and Economics. Nitrogen tritiuoride can be formed from a wide variety of chemical reactions. Only two processes have been technically and economically feasible for large-scale production the electrolysis of molten ammonium acid fluoride and the direct fluorination of the ammonia in the presence of molten ammonium fluoride. In the electrolytic process, NF is produced at the anode and H2 is produced at the cathode. In a divided cell of 4 kA having nickel anodes, extensive dilution of the gas streams with N2 was used to prevent explosive reactions between NF and H2 (17). 

A special precaution is imperative in handling elemental fluorine and chlorine tnfluoride. Both gases are extremely corrosive and so reactive that they are very seldom used without dilution with inert gases such as nitrogen, helium, or argon. Fluorine is now available in mixtures with nitrogen. Fluorine is very toxic in... 

---