P&M-Invest

RU Patent 2134257 (April 1998) " Method of hydrofluorination of fluoro olefins with HF in the presence of activated carbon catalyst promoted with alkali metal fluorides "  

Polyfluoroaromatic compounds are prepared by heating corresponding halogenated aromatics with alkali metal fluorides in presence of catalyst, in particular N,N',N"-hexasubstituted guanidinium halide. Reaction is carried out in medium composed of products of partial fluorination of initial halogenated aromatics, while desired products are continuously withdrawn. EFFECT: increased yield of desired products. 3 cl, 10 ex.

A process for preparing polyfluoroarom. compds. by heating halogen-containing aromatic compds. with alkali metal fluorides in the presence of a catalyst, N,N',N''-hexa-substituted guanidinium halide, in the medium of products of incomplete fluorination of a halogen-containing compound with simultaneous continuous withdrawal of target products by fractionation or distillation is disclosed. Thus, hexachlorobenzene 30, hexaethylguanidinium chloride 2, potassium fluoride 48, a mixture of incomplete fluorination of hexachlorobenzene (C6FnClm where n = 1-4, M = 2-5) 20 kg were heated at 160-170^o, hexafluorobenzene was isolated by distillation at 80-85 ^o yielding 17.5 kg (88.4% yield).

A method for the decarboxylation of perfluoroalkylcarbonyl halides or perfluorinated carboxylic acid esters into the corresponding perfluoroolefins or perfluoroalkyl vinyl ethers that are used as monomers is described. The decarboxylation reaction is conducted at 100-300^o in the presence of a catalyst comprising a carrier such as activated carbon, magnesium oxide, calcium oxide, barium oxide, zinc oxide, alumina, nickel oxide, or silica, promoted with 20-50% of an alkali metal halide. The yield of synthesized perfluoroolefins or perfluoroalkyl vinyl ethers is up to 95%.

New method for the manufacture of nitrogen trifluoride suitable for use in semiconductor device fabrication is described. The method includes fluorination of carbamide or products of its decomposition by fluorine in anhydrous hydrogen fluoride at -20^o-0^o and fluorine to initial compds. molar ratio up to 3. Concentration of initial compds. in anhydrous fluorine is 20-50 weight%. The method is explosion-proof and allows to produce product with maximum content of nitrogen trifluoride and minimal concentration of impurities with yield up to 90%.

Gaseous nitrogen trifluoride is freed of carbon tetrachloride impurities via selective adsorption by dehydrated erionite at -30^o and 30^o followed by displacement of carbon tetrachloride with inert gas, desorption and condensation of thus purified nitrogen trifluoride. Purity of the product is 99.99% and content of CF4 is no more then 10 ppm. Enhanced economical efficiency and easy industrial implementation are ensured.

A process for preparing polyfluoroaromatic compounds by heating halogen-containing aromatic compounds with alkali metal fluorides in the presence of a catalyst, N,N',N"-hexa-substituted guanidinium halide, in the medium of products of incomplete fluorination of a halogen-containing compound with simultaneous continuous withdrawal of target products by fractionation or distillation.

The present invention relates to a process for producing fluorinated aliphatic compounds by pyrolysis of perfluorocarboxylic acids and their derivatives--halides and esters. The pyrolysis is carried out in the presence of a catalyst consisting of a carrier most preferably selected from the series comprising active carbon, magnesium oxide, calcium oxide, barium oxide, zinc oxide, aluminum oxide, nickel oxide, oxides of silicon promoted with alkali metal halides, selected from the series comprising fluorides, chlorides bromides, iodides of sodium, potassium, rubidium, cesium, at a temperature in the range of from about 100.degree. C. to about 450.degree. C.; with producing fluorinated aliphatic compounds selected from the series comprising perfluoroolefins, polyfluoroolefins and their derivatives; and also in the presence additionally of hydrogen fluoride with the formation of fluorinated aliphatic compounds selected from the series comprising polyfluoroalkanes and their derivatives.

New method for the manufacture of nitrogen trifluoride suitable for use in semiconductor device fabrication is described. The method includes fluorination of carbamide or products of its decomposition by fluorine in anhydrous hydrogen fluoride at -20^o-0^o and fluorine to initial compds. molar ratio up to 3. Concentration of initial compds. in anhydrous fluorine is 20-50 weight%. The method is explosion-proof and allows to produce product with maximum content of nitrogen trifluoride and minimal concentration of impurities with yield up to 90%.