Abstract: This invention relates to a continuous gaseous-phase process for the preparation of trichlorotrifluoroethane, dichlorotetrafluoroethane and monochloropentafluoroethane, in predetermined proportions, from tetrachloroethylene, chlorine and hydrofluoric acid in the presence of a catalyst. The process is characterized by the combination of two chlorination-fluorination reactors in sequence, a parallel fluorination-dismutation reactor, and a separation unit for extracting the desired products and recycling recovered hydrofluoric acid and non-fluorinated or insufficiently fluorinated products. The process advantageously yields dichlorotetrafluoroethane containing less than 7% asymmetric isomer, and trichlorotrifluoroethane containing less than 2% asymmetric isomer.

Abstract: Processes for preparing vanadium- and chlorine-free sodium bichromate which comprises concentration of a sodium chromate liquor so as to cause formation of crystals of neutral sodium chromate tetrahydrate, separation of these crystals from their mother liquor, treatment thereof with sulfuric acid, concentration of the acid solution obtained, and after separation of insoluble sodium sulfate so formed, crystallization of sodium bichromate.

Abstract: A process for the preparation of an optical brightening agent falling within the formula: ##SPC1##In which R represents an alkyl group containing 1 to 4 carbon atoms, R.sub.1 and R.sub.2 each represent a hydrogen atom, an alkyl group containing 1 to 4 carbon atoms or a phenyl group either unsubstituted or substituted by at least one alkyl group containing 1 to 4 carbon atoms, R.sub.3 and R.sub.4 each represent an alkyl group containing 1 to 4 carbon atoms and A.sup.- represents a monovalent anion which comprises reacting a compound of the formula: ##SPC2##In which R.sub.1, R.sub.2, R.sub.3, R.sub.4, and A.sup.- have the meanings given above, with an alcoholate of the formula RO-Me in which R represents an alkyl group containing 1 to 4 carbon atoms and Me is an alkali metal; compounds falling within the formula: ##SPC3##Wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and A.sup.- have the meanings given above.

Abstract: Anti-adherent material for coming into contact with the epidermis such as sheets, surgical dressings, various kinds of bandages and the like are disclosed which comprise a homopolymer or copolymer of tetrafluoroethylene containing at least about 50% tetrafluoroethylene deposited upon a support material which is resistant to the fritting temperature of the homopolymer or copolymer, the support material containing from about 25 to 90% homopolymer or copolymer and from 10 to 75% support material and possessing regularly disposed perforations for from about 0.1 to 10% of the surface thereof.