Abstract: A process for brominating fluorine-containing halogenated hydrocarbons is disclosed which comprises the step of reacting at least one halogenated fluorohydrocarbon compound of formula (I) ##STR1## wherein R.sub.1 represents hydrogen, fluorine, chlorine, bromine or a lower alkyl group which is perhalogenated by a halogen selected from the group consisting of fluorine, chlorine and bromine;R.sub.2 represents hydrogen, fluorine, chlorine, or bromine, and;R.sub.3 represents fluorine or perfluorinated lower alkyl, in gaseous form with bromine under irradiation with light having a wavelength from about 250 nm to about 600 nm in the presence of an active amount of chlorine not exceeding about 2 moles per mole of bromine at a reaction temperature not exceeding 300.degree. C., which is sufficient for transforming the reactants into sufficiently stable gaseous compounds and for substituting the hydrogen in a compound of formula (I) by bromine to form a compound of formula (II) ##STR2## wherein R.sub.1, R.sub.2 and R.

Abstract: Disclosed is a process for the production of sulphur hexafluoride comprising the steps of reacting fluorine and molten sulphur, removing lower-boiling by-products, separating a portion of the sulphur hexafluoride from higher-boiling by-products and treating the residue containing the higher-boiling by-products at a temperature between about 450.degree. and 800.degree. C. for a period of time between about 0.1 and 25 seconds. The treatment step may be carried out in the presence of elementary fluorine, and provision may be made for recycling the treated or untreated residue to the reaction stage. An apparatus for carrying out the process is also disclosed.

Abstract: Disclosed is a process for the preparation of calcium fluoride comprising reacting hexafluoro silicic acid with calcium carbonate in the presence of sulfate or aluminum ions within a pH range of between about 2 and 6 and separating the calcium fluoride precipitate from the resulting aqueous silica sol.

Abstract: Disclosed is a process for the production of sulphur hexafluoride comprising the steps of reacting fluorine and molten sulphur, removing lower-boiling by-products, separating a portion of the sulphur hexafluoride from higher-boiling by-products and treating the residue containing the higher-boiling by-products at a temperature between about 450.degree. and 800.degree. C. for a period of time between about 0.1 and 25 seconds. The treatment step may be carried out in the presence of elementary fluorine, and provision may be made for recycling the treated or untreated residue to the reaction stage. An apparatus for carrying out the process is also disclosed.

Abstract: Disclosed is a process for the preparation of calcium fluoride comprising reacting hexafluoro silicic acid with calcium carbonate in the presence of sulfate or aluminum ions within a pH range of between about 2 and 6 and separating the calcium fluoride precipitate from the resulting aqueous silica sol.

Abstract: Disclosed is a process for the recovery of antimony pentachloride from catalyst solutions used in the fluorination of chlorinated hydrocarbons characterized in that the exhausted catalyst solution containing antimony ions and high boiling halogenated hydrocarbons is chlorinated to convert the Sb.sup.3.sup.+ to Sb.sup.5.sup.+ followed by treatment of the solution with hydrogen fluoride to give SbCl.sub.x F.sub.y compounds, wherein x is 4-2 and y is 1-3, the sum of x+y being 5, and to convert the high boiling halogenated hydrocarbons to lower boiling halogenated hydrocarbons, thereafter removing the halogenated hydrocarbons having a lower boiling temperature than the boiling point of SbCl.sub.x F.sub.y and converting the remaining SbCl.sub.x F.sub.y compound with carbon tetrachloride to form antimony pentachloride which is thereafter separated from the remaining organic compounds and inorganic residue.

Abstract: Processes for the separation and purification of a perhaloalkanoic acid or mixture of perhaloalkanoic acids having the formulaA--(CFX--CFY).sub.n --CFX--COOHin which A is a perfluoromethyl, perfluoroethyl, perfluoropropyl or perfluoroisopropyl radical, X is a fluoro or a trifluoromethyl radical, Y is a fluoro or chloro radical, and n is an integer from 1 to 4, from a mixture containing the said acid or mixture of acids and a perhaloalkane or mixture of perhaloalkanes having the formulaA--(CFX--CFY).sub.n --CFX--CFYZin which formula A, X, Y and n have the same significance as in the previous formula and Z is an iodo, chloro or bromo radical, which comprises adsorbing the said mixture in the form of a liquid upon a chromatographic column of adsorbent silica gel particles and subsequently eluting the perhaloalkane or perhaloalkanes therefrom with a weakly polar eluent and subsequently eluting the perfluoroalkanoic acid or acids therefrom with a strongly polar eluent.