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Bromochlorodifluoromethane (BCF), also referred to by the code numbers Halon 1211 and Freon 12B1, is a haloalkane with the chemical formula C F 2 Cl Br. It is used for fire suppression, especially for expensive equipment or items that could be damaged by the residue from other types of extinguishers. [ 1 ]
Civilian models in 2-3/4, 3, and 4 lb sizes were also made. It is considered good practice to avoid all unnecessary exposure to Halon 1301, and to limit exposures to concentrations of 7% and below to 15 minutes. Exposure to Halon 1301 in the 5% to 7% range produces little, if any, noticeable effect.
Halon 1301 causes only slight giddiness at its effective concentration of 5%, and even at 15% those exposed remain conscious but impaired and suffer no long-term effects. (Experimental animals have also been exposed to 2% concentrations of Halon 1301 for 30 hours per week for 4 months, with no discernible health effects.
2,2-Dichloro-1,1,1-trifluoroethane can be produced by reacting tetrachloroethylene with hydrogen fluoride in the gas phase. This is an exothermic reaction and requires a catalyst: This is an exothermic reaction and requires a catalyst:
Halon 14 (tetrafluoromethane) Halon 2011B (1-bromo-2-chloroethane) Halon 2301 (1,1,1-trifluoro-2-bromoethane) Halon 2311 (1,1,1-trifluoro-2,2-chlorobromoethane, halothane) Halon 242 (1,2-dichlorotetrafluoroethane) Halon 2402 (dibromotetrafluoroethane, C 2 Br 2 F 4)—used as a fire extinguisher; Halon 2501 (pentafluorobromoethane) Halon 2600 ...
1,2-Dibromotetrafluoroethane (C 2 Br 2 F 4) is a haloalkane. It is also known under codenames R-114B2 and Halon 2402. It is a colorless liquid with a boiling point of 47.2 °C. R-114B2 is occasionally used in fire suppression systems. It is highly volatile, passes through soil to air, and can be detected in the parts-per-quadrillion range. [2]
For example, R-22 has one carbon atom, one hydrogen atom (2−1 = 1), two fluorine atoms, and one chlorine atom (4−2−1 = 1), so it is chlorodifluoromethane, while R-134 has two carbon atoms (2−1 = 1), two hydrogen atoms (3−1 = 2), four fluorine atoms, and no chlorine atoms (6−2−4 = 0), so it is one of the tetrafluoroethanes. This ...
This model, called 75/34 Mod. SF, was thus adopted by the Royal Army and production was assigned to Ansaldo . This intervened on the muzzle, shortening it and modifying the muzzle brake, thus obtaining the standard version 75/32 Mod. 1937. The Cannone da 75/32 was designed by Ansaldo and the first examples were produced in 1937.