Abstract:
The selectivity of copper as the catalyst for the reaction of short-chain perfluoroalkyl iodides with tetrafluoroethylene is increased if a further transition metal is employed as a cocatalyst.
Abstract:
The toxic perfluoro-2-methyl-2-pentene can be removed from perfluoro-4-methyl-2-pentene by treating the mixture with lower alkanols, the toxic isomer being converted into high boiling-point compounds which can be easily removed. The high-purity perfluoro-4-methyl-2-pentene so obtained is suitable as a substitute for chlorofluorocarbons.
Abstract:
A process is described for the preparation of the title compounds from the corresponding iodine-containing compounds by reaction with bromide or chloride ions present as salts, in a dipolar aprotic solvent, in the presence of a metal complex compound which contains chromium, nickel, cobalt or rhodium as the central atom and contains, per central atom, 1, 2 or 3 bromine or chlorine atoms and at least one additional phosphorus-containing ligand, at 20.degree. to 140.degree. C. Good yields are obtained in this way without the difficulties associated with the known procedure using elemental halogens at elevated temperatures. The compounds prepared can be used in the medical sector and as liquids resistant to high temperatures.
Abstract:
A process is described for the preparation of perfluorocarboxylic acids by oxidizing perfluoroalkylalkenes with permanganate in aqueous solution, catalytic amounts of at least one quaternary ammonium salt containing alkyl and/or arylalkyl groups being added. It is possible by these means to prepare even perfluorocarboxylic acids having a fairly long chain in a high state of purity in a readily controllable reaction and in a good space-time yield.
Abstract:
Stable aqueous, colloidal dispersions, having a high shear stability, of copolymers of tetrafluoroethylene and ethylene, which may also contain at least one further comonomer, are described. Such dispersions are prepared in the presence of a mixture of perfluorooctanoic acid and perfluorononanoic or perfluorodecanoic acids or salts thereof.
Abstract:
The present invention provides a process for the photochemical production of compounds of the general formula:R--(C.sub.2 R.sub.4 ').sub.n --Xby telomerisation of an alkyl halide R--X as telogen and of an olefin C.sub.2 R.sub.4 ' as monomer, in which R is an alkyl radical which is not halogenated or is partly or completely halogenated, R' can in each case be the same or different and, independently of one another, are hydrogen, fluorine, chlorine or bromine atoms or unsubstituted or substituted alkyl or aryl radicals, n is a natural number from 2 to 10 and X is a bromine or iodine atom, wherein(1) a reaction mixture is produced which contains the olefin and the alkyl halide,(2) this reaction mixture is irradiated with ultra-violet light, the wavelength of which is from 230 to 350 nm, and(3) the end product or end products is/are recovered from the reaction mixture.
Abstract:
The halogenotetrafluoropropionic acid 3-iodotetrafluoropropionic acid of the formula ICF.sub.2 CF.sub.2 COOH, it is prepared by reacting iodine, tetrafluoroethylene and ethylene in a one-pot reaction under specific conditions, reacting the resulting compound ICF.sub.2 CF.sub.2 CH.sub.2 CH.sub.2 I with a base in order to eliminate hydrogen iodide and oxidizing the compound ICF.sub.2 CF.sub.2 --CH.dbd.CH.sub.2 thus obtained to give 3-iodotetrafluoropropionic acid. The halogenotetrafluoropropionic acid is an advantageous starting compound for the preparation of valuable unsaturated compounds containing functional groups.
Abstract:
A process is described for the preparation of 2-alkenyl 1,1,2-trifluoro-2-halogenoethyl ethers by reacting optionally substituted allyl alcohols with fluoroolefins in the presence of an alkali metal hydroxide as catalyst, in which the reaction is carried out by intimately mixing the reactants with an N,N-dialkylcarboxylic acid amide. The said ethers are suitable as intermediate products for the preparation of addition products by the addition of alcohols, primary or secondary amines or R.sub.3 SiH compounds, and are also suitable as comonomers for fluorine-containing copolymers.
Abstract:
Hydraulic fluids the primary properties of which comply with the official specifications and, moreover, which have a good lubricating effect, a high oxidation stability and a high acid stability consist of about 10 to 60% by weight of a nitrogen-containing boric acid ester, about 5 to 30% by weight of an alkyl-polyethylene glycol tert. butyl ether and about 35 to 75% by weight of a glycol monoalkyl ether. The nitrogen-containing boric acid ester is a reaction product of an alkoxylated monoalkyl amine, orthoboric acid and optionally a glycol.
Abstract:
The safety of secondary lithium cells is remarkedly enhanced when partially fluorinated ethers of the formulaeRO--�(CH.sub.2).sub.m O!.sub.n --CF.sub.2 --CFH--X (I)and/orX--CFH--CF.sub.2 O--�(CH.sub.2).sub.m O!.sub.n --CF.sub.2 --CFH--X(II)are being used, wherein R is a straight-chain alkyl group containing 1 to 10 carbon atoms or a branched alkyl group containing 3 to 10 carbon atoms, X is fluorine, chlorine or a perfluoroalkyl group containing 1 to 6 carbon atoms, which may also contain ethereal oxygen, m is an integer from 2 to 6 and n is an integer from 1 to 8. Preferred are compounds of the formula (I), wherein R is a methyl group, X is fluorine, m is 2 and n is an integer from 1 to 3 and also compounds of the formula (II), wherein m is 2 and n is an integer from 1 to 3.