Fluorine gaseous

We have demonstrated for the first time, that metal-catalyzed initiation of the polymerization of main chain fluorinated gaseous monomers such as VDF, can easily be accomplished at 0-100°C, including at rt upto 40°C, directly Irom a wide variety of alkyl, semifluorinated and perfluoroalkyl halides (Cl, Br, I), using a visible light, Mn2(CO)io photomediated protocol, carried out in low pressure glass mbes, and which is especially successful in dimethyl carbonate. 

Fluorine, gaseous, technical grade Fluoroboric acid, technical grade Formaldehyde, 15%... 

Fluorine is exceedingly reactive and combines vigorously with most elements. Some ignite spontaneously in gaseous fluorine at room... 

Oxygen difluoride, OFj, is obtained when gaseous fluorine is passed through very dilute (27 ) caustic soda solution ... 

Compressors and blowers for gaseous fluorine service vary in design from multistage centrifugal compressors to diaphragm and piston types. 

Disposal. Fluorine can be disposed of by conversion to gaseous perfluorocarbons or fluoride salts. Because of the long atmospheric lifetimes of gaseous perfluorocarbons (see Atmospheric models), disposal by conversion to fluoride salts is preferred. The following methods are recommended scmbbing with caustic solutions (115,116) reaction with soHd disposal agents such as alumina, limestone, lime, and soda lime (117,118) and reaction with superheated steam (119). Scmbbing with caustic solution and, for dilute streams, reaction with limestone, are practiced on an industrial scale. 

Elemental fluorine is used captively by most manufacturers for the production of various inorganic fluorides (Table 5). The market for gaseous fluorine is small, but growing. The main use of fluorine is in the manufacture of uranium hexafluoride, UF, by... 

High Purity Aluminum Trifluoride. High purity anhydrous aluminum triduoride that is free from oxide impurities can be prepared by reaction of gaseous anhydrous HF and AlCl at 100°C, gradually raising the temperature to 400°C. It can also be prepared by the action of elemental fluorine on metal/metal oxide and subsequent sublimation (12) or the decomposition of ammonium duoroaluminate at 700°C. 

Equipment should be carefiiUy and completely degreased and passivated with low concentrations of fluorine or the gaseous halogen fluoride before use. Special care should be taken that valves are completely disassembled and each part carefiiUy cleaned. 

R. L. Earrar, Jr., and E. J. Barber, Some Considerations in the Handling of Fluorine and the Chlorine Fluorides, report K/ET-252, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Term., 1979. 

To convert naturally occurring uranium oxide, yellow cake or U Og, to the gaseous UF, hydrofluoric acid is first used to convert the U Og to UF. Further fluorination using fluorine (generated from more HF) is employed to convert the UF to UF. The UF is then processed at gaseous diffusion enrichment plants. 

Many different processes using HF as a reactant or source of fluorine are employed in the manufacture of fluorinated chemical derivatives. In many cases the chemistry employed is complex and in some cases proprietary. Electrochemical fluorination techniques and gaseous fluorine derived from HF are used in some of these appHcations. 

Another impetus to expansion of this field was the advent of World War 11 and the development of the atomic bomb. The desired isotope of uranium, in the form of UF was prepared by a gaseous diffusion separation process of the mixed isotopes (see Fluorine). UF is extremely reactive and required contact with inert organic materials as process seals and greases. The wartime Manhattan Project successfully developed a family of stable materials for UF service. These early materials later evolved into the current fluorochemical and fluoropolymer materials industry. A detailed description of the fluorine research performed on the Manhattan Project has been pubUshed (2). 

The two possible initiations for the free-radical reaction are step lb or the combination of steps la and 2a from Table 1. The role of the initiation step lb in the reaction scheme is an important consideration in minimising the concentration of atomic fluorine (27). As indicated in Table 1, this process is spontaneous at room temperature [AG25 = —24.4 kJ/mol (—5.84 kcal/mol) ] although the enthalpy is slightly positive. The validity of this step has not yet been conclusively estabUshed by spectroscopic methods which makes it an unsolved problem of prime importance. Furthermore, the fact that fluorine reacts at a significant rate with some hydrocarbons in the dark at temperatures below —78° C indicates that step lb is important and may have Httie or no activation energy at RT. At extremely low temperatures (ca 10 K) there is no reaction between gaseous fluorine and CH or 2 6... 

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