Abstract: The methyl and ethyl esters of trifluoroacetic acid or chlorodifluoroacetic acid can be prepared in a technically simple manner from the corresponding acid chlorides and methanol or ethanol, respectively, in the presence of an “onium” salt of the acid as a catalyst. The alcohol is used in a stoichiometric excess, namely the molar ratio of alcohol to acid chloride is selected such that operation is in the region of a two-phase reaction. One of the phases is formed by the desired ester product, which is obtained in a high purity without any distillation.

Abstract: Fluxing agents comprising potassium fluorostannate and/or cesium fluorostannate which can be used for brazing or soldering components of aluminum or of an aluminum alloy, even by solderless brazing or soldering. Conventional fluxing agents or other fluorometallates, such as alkali metal fluorozincates and/or alkali metal fluorosilicates, can also be added to the fluorostannate-containing fluxing agent. The fluxing agents of the invention can be applied by either dry or wet fluxing methods.

Abstract: A method for the recovery or separation of sulfur oxyfluorides from gas mixtures, in which the gas mixture passes through at least one adsorption stage or membrane stage containing or consisting of zeolites with a modulus >10. The sulfur oxyfluorides fixed to the adsorbent may be made available for use after desorption. The sulfur oxyfluorides enriched through the membrane can be re-used directly.

Abstract: An improved process for preparing carboxylic acid esters from acid chlorides, acid bromides or acids and alcohols provides for performing the esterification in the presence of the adduct (onium salt) of the corresponding carboxylic acid and 1,5-diazabicyclo[4.3.0]-non-2-ene or 1,8-diazabicyclo[5.4.0]-undec-7-ene. Alternatively, it is possible to operate in the presence of the corresponding carboxylic acid and an onium salt of the corresponding carboxylic acid.

Abstract: Hydrogen fluoride adducts and ammonium fluorides are used for fluorinating acid chlorides and halocarbon compounds such as chloroalkanes or chloronated ethers. The used adducts can be regenerated and then reused in the fluorination reactions.

Abstract: A process for purification of 1,1,1,3,3-pentafluorobutane (HFC-365mfc) containing a decreased amount of hydrogen chloride, hydrogen fluoride and/or unsaturated impurities. To this end crude 1,1,1,3,3-pentafluorobutane is treated in the liquid phase with a solid, inorganic sorption agent and/or with diatomic molecules which and to C—C multiple bonds. The product to be purified is preferably treated with elemental fluorine. The contents of hydrogen chloride and hydrogen can each be decreased to below 1 ppm. The content of unsaturated (chlorine)-fluorine-compounds can be decreased to below 20 ppm, and the content of unsaturated C2 compounds can be decreased to below 10 ppm. It has also been discovered that fluorotrichloroethylene can be used as a control substance to monitor the purification of 1,1,1,3,3-pentafluorobutane.

Abstract: Electrolyte systems for lithium batteries with enhanced safety containing at least one lithium-containing conductive salt and at least one electrolyte liquid, in which the electrolyte liquid includes an effective amount of at least one partially fluorinated amide of formula (I) R1CO—NR2R3  (I) in which R1 is a linear C1-C6 alkyl group, or a branched C3-C6 alkyl group, in which one or more hydrogen atoms are replaced by fluorine atoms; or a C3-C7 cycloalkyl group optionally substituted one or more times by a linear C1-C6 alkyl group and/or branched C3-C6 alkyl group, in which one or more hydrogen atoms of are replaced by fluorine atoms; and R2 and R3 independently represent an identical or different linear C1-C6 alkyl group, a branched C3-C6 alkyl group or a C3-C7 cycloalkyl group, or R2 and R3 together with the amide nitrogen form a saturated five or six-member nitrogen-containing ring.

Abstract: A method for producing carboxylic acid fluorides of the formula RCFXC(O)F, where X represents fluorine or chlorine, in good yields and with good selectivity for the carboxylic acid fluorides by reacting compounds of the formula RCFXCHFCl with oxygen by photochemical oxidation in the gaseous phase, preferably under sensitization with chlorine and using light having a wavelength &lgr;≧280 nm, which conditions make it possible to work without the use of pressure. Glass apparatus may be covered with a protective coating so as to protect it against traces of hydrogen fluoride. To this end, for example, heat-shrinkable sleeves made of light-permeable hydrogen fluoride-resistant material may be used. Polytetrafluoroethylene, polyfluoropropylene or a mixture thereof are especially suitable for this purpose.

Abstract: A method of preparing sulfuryl fluoride by disproportionation of sulfuryl chloride fluoride in the gas phase on activated carbon.

Abstract: Gas mixtures of SF6 and N2, which have been used, for example, as an insulating filler gas for underground cables, for insulating-gas window panes or as a filler gas for car tires and SF6/air mixtures which have been used as a protective gas when casting magnesium can be separated if they are contacted with hydrophobic zeolites of a certain pore size as selective adsorption agent for sulfur hexafluoride. For a relatively high SF6 concentration, the mixture is preferably first subjected to a membrane separation process and the permeate is contacted with the adsorption agent. The invention also relates to an apparatus for carrying out the process. The process may also be used for separating SF6 from exhaust gases.

Abstract: Components made of aluminum and aluminum alloys can be brazed at temperatures of up to 600° C. using a fluxing agent composed of alkali fluorozincate or alkali fluoride/zinc fluoride mixtures. Other fluxing agents, for example those composed of potassium fluoroaluminate can be used in addition. Alkali fluorozincate fluxing agents, especially potassium and cesium fluorozincate fluxing agents, act not only as a fluxing agent but also improve the surface quality since zinc and alkali fluoroaluminates are deposited on the surface of the components. The invention also relates to new fluxing agents containing alkali metal fluorozincates.

Abstract: A method for the production of polyurethane foams and of thermoplastic foams is described. As blowing agent, a composition is used, which contains or consists of pentafluorobutane, preferably pentafluorobutane (HFC-365mfc) and at least one further blowing agent selected from the group comprising; difluoromethane (HFC-32); difluoroethane, preferably 1,1-difluoroethane (HFC-152a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1,2-tetrafluoroethane (HFC-134a); hexafluoropropane, preferably 1,1,1,3,3,3-hexafluoropropane (HFC-236fa); 1,1,2,3,3,3-hexafluoropropane (HFC-236ea) and heptafluoropropane, preferably 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), low-boiling, optionally halogenated hydrocarbons and/or low-boiling, optionally halogenated ethers.

Abstract: The production of a potassium fluoroaluminate having a low melting point, which can be used as a flux when soldering aluminum. The potassium fluoroaluminate is prepared in an aqueous medium from aluminum hydroxide, hydrogen fluoride and potassium hydroxide in a molar ratio of aluminum:fluorine:potassium of approximately 1:5:2. After drying at 80° C. under vacuum, the resulting potassium fluoroaluminate has a differential scanning calorimetry melting point of about 548° C.

Abstract: A flux which contains irreversibly dehydrated K2AlF5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Abstract: Organic compounds, e.g. fluorinated organic compounds such as fluorinated carboxylic acids or fluorinated carboxylic acid chlorides, may contain small amounts of carboxylic acid fluorides, hydrogen fluoride or hydrolyzable fluoride, which during the preparation of derivatives of the fluorinated organic compounds, for example by esterification, may yield corrosive fluorides or hydrogen fluoride. The invention is a method for the synthesis and/or purification of preferably fluorinated organic compounds such as carboxylic acids, carboxylic acid chlorides and derivatives such as esters thereof, starting from corresponding carboxylic acid chlorides containing acid fluorides or hydrolyzable fluoride, and alcohols under the catalytic action of “onium” salts of carboxylic acids, to obtain products which have a low fluoride content. Alternatively, an inorganic oxide adsorbent is utilized.

Abstract: Sulfuryl fluoride is prepared selectively and in a high yield from sulfur dioxide and elemental fluorine in the presence of an alkali fluoride and hydrogen fluoride. The preferred alkali fluoride is potassium fluoride.

Abstract: A flux which contains irreversibly dehydrated K2AlF5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Abstract: Flux residues from aluminium soldering fluxes composed of alkali metal metallates, especially fluoroaluminates of the alkali metals, in particular potassium and cesium, can be recycled by adding them to the reaction mixture used for the production of hydrogen fluoride from fluorspar and sulfuric acid or oleum. In this way the fluorine content of the flux residues becomes reusable, and the anhydrite which is produced can advantageously be used for conventional purposes.

Abstract: Sulfuryl fluoride (SO.sub.2 F.sub.2) frequently contains chlorine, sulfur dioxide and other acidic impurities owing to its production. Effective purification is possible if the sulfuryl fluoride is contacted with hydrogen peroxide or a precursor thereof, preferably in an aqueous solution. The purified product is suitable as a pesticidal agent, for example.

Abstract: A method of avoiding generation of waste water while brazing components made of aluminium or an aluminium alloy using a flux, especially a flux composed of an aqueous suspension of potassium fluoroaluminate. Since used suspension is replaced with fresh suspension after a given period of time and the apparatus regularly have to be cleaned, waste water is produced which contains flux, e.g. potassium fluoroaluminate. In the past, such waste water has been discharged into the environment. It has now been discovered that such waste water can be recycled to the brazing process after separation of the flux. In this manner, the production of waste water can be largely avoided. Since surfactants are frequently used, and these are likewise recirculated, a corresponding saving in terms of surfactant is possible. Furthermore, the environment is protected correspondingly.