摘要:
Perfluorobutadiene and higher alkandienes, with terminal double bonds, are obtained from α,ω-dibromo or α,ω-bromo iodo perfluoroalkanes by dehalofluorination carried out at limited reaction times by means of an organometallic compound in the presence of an aprotic solvent selected from the class of hydrocarbons or a polar aprotic solvent selected from the class of ethers.
摘要:
The new compound 2-bromo-1ʹ,2ʹ-dichloroperfluoro diethyl ether of formula; BrCF₂-CF₂-O-CFCl-CF₂Cl is obtained from BrCF₂CF₂OF by reaction with olefin CFCl=CFCl, bromohypofluorite being introduced into the reaction mixture in the form of a solution in an inert solvent based on chlorofluorohydrocarbon.
摘要:
A process for the preparation of hydro(halo)fluoroalkanes by direct fluorination of the corresponding hydro(halo)alkenes in liquid phase with elemental fluorine at low temperatures (below 0°C).
摘要:
A process for the purification of oils such as perfluoropolyether oils, silicone oils or oils based on hydrocarbons, which are contaminated with different impurities, in particular, with dispersed solid matter which can be filtered only with difficulty with conventional filters, which process comprises filtration carried out with a filter of the tangential-flow type, the pores of the filter element having a diameter of less than 0.4µm.
摘要:
A method of preparing perfluoropolyethers having a regulated molecular weigh starting from the product obtained by photochemical oxidation of C 2 F 4 and having a various content of oxygen peroxide, consisting'in heat-treating the peroxidized product in order to partially remove the oxygen peroxide till reducing it to a relatively lowvalue which is prefixed as a function of the molecular weight to be obtained for the final product, and in the subsequent treatment with gaseous fluorine at high temperature.
摘要:
Neutralization of perfluoropolyethers is accomplished by reacting them with gaseous fluorine in the presence of radiations having a wavelength from 200 to 500 nm. The presence of radiations permits to operate at lower temperatures and with higher reaction rates, and to reach an exhaustive neutralization.
摘要:
The surfaces of building materials, including marble, stone, sandstone, tiles, and cement mixes, and articles and structures manufactured therefrom are protected against atmospheric and polluting agents by applying thereto a protective agent consisting of a vinylidene fluoride polymer or copolymer comprising 55-100 mole % of vinylidene fluoride, 0-45 mole % of hexafluoropropene and 0-30 mole % of tetrafluoroethylene. Such polymers or copolymers are, preferably applied onto the surface to be protected in the form of solutions in volatile solvents.
摘要:
The present invention relates to telomers of 1,2-dichloro-1,2-difluoroethylene and to a process of preparing them. 1,2-dichloro-1,2-difluoroethylene is reacted, at a temperature of from -100°C to +50°C, with a perhalofluorooxy compound of formula R x -OF wherein R x represents, among other, a perhaloalkyl radical of from 1 to 10 carbon atoms. Telomers are obtained which have, among others, the formulae R X O-(CFCl) n -F R x O-(CFCl) n -OR x R y -(CFCl) n -F and F-(CFCl) n -F, wherein R y represents, among others, a perhaloalkyl radical containing from 1 to 9 carbon atoms. Most of the resulting telomers are new products.