Solvay Fluor Und Derivate Gmbh

Solvay Fluor Gmbh

Kali-chemie Aktiengesellschaft

Solvay Umweltchemie Gmbh

Hans-Walter Swidersky

Werner Rudolph

Thomas Born

Johannes Eicher

Alfred Ottmann

Andreas Becker

Placido Garcia-Juan

Heinz-Joachim Belt

Carsten Brosch

Karlheinz Fazniewscy

Matthias Rieland

Karl-Heinz Fazniewscy

Ulrich Hartmann

Veronika Radonz

Frank Moewius

Heinz R Feist

Werner Legat

Andrea Feldmann

Manfred Meisel

Aluminum parts, e.g., heat exchangers, with improved resistance towards corrosion caused by contact with stationary water or aqueous compositions such as cooling water can be obtained by addition of Li compounds in specific amounts to the flux used for brazing the parts. LiF and especially Li fluoroaluminates are very suitable. The flux and the Li salt can be dispersed in water or an aqueous composition separately.

Flux forming an insoluble brazing residue

Aluminum parts, such as heat exchangers, with improved resistance towards corrosion caused by contact with stationary water or aqueous compositions can be obtained by addition of Li compounds to the flux used for brazing such parts. LiF and especially Li fluoroaluminates are very suitable. Another aspect of the invention concerns fluxes containing Li salts and their use for brazing of aluminum parts.

Anticorrosive flux

A fine particulate flux, an aqueous flux preparation comprising this flux, a method for the manufacture of a coated part of aluminum, aluminum alloys, steel, copper or titanium using such flux, and a method for brazing parts of aluminum or aluminum alloys to parts of aluminum, aluminum alloys, steel, copper or titanium using such flux. The flux can be obtained by sieving, or it can be obtained by removing solids, e.g., in a cyclone, from the drying gases obtained when wet fluxes are dried, especially after their manufacture. Fine particulate flux increases the viscosity of flux preparations comprising the flux dispersed in water or an aqueous or liquid organic carrier.

Fine particulate flux

A flux or a flux preparation, which contains complex alkali metal fluorides and additionally includes a water-soluble polymer, preferably polyvinyl alcohol or a polyvinyl alcohol derivative. The water-soluble polymer may be contained in the flux preparation as a granulate or powder or used as a water-soluble package for the flux or flux preparation.

Fluxing agent

A flux based on alkali fluoroaluminate is described which is highly suitable for dry application ('dry fluxing'). This is a flux which is free of fine-grained fraction, which is defined by a range of grain-size distribution.

Brazing flux for dry application

A flux based on alkali fluoroaluminate is described which is highly suitable for dry application (&ldquo;dry fluxing&rdquo;). This is a flux which is free of fine-grained fraction, which is defined by a range of grain-size distribution.

A process for preparing R113a from Rl13, and R123 from R123a or R123b by rearrangement over AlCl.sub.3, in which when the reaction mixture is heated sudden start-up of the reaction, which often causes large amounts of heat to be released and the reaction to run away, is prevented by using a specially activated AlCl.sub.3, which has been activated by means of a metal halide selected from the group consisting of NaF.multidot.nHF with 0&lt;n.ltoreq.2, AgCl and FeCl.sub.3. In addition to it being considerably easier to control the reaction, shorter reaction times for the rearrangement and a decrease in the amount of by-products which are formed, are observed.

Chlorofluoro(hydro)carbon conversion process

A process for preparing R113a from R113, and R123 from R123a or R123b by rearrangement over AlCl.sub.3, in which when the reaction mixture is heated sudden start-up of the reaction, which often causes large amounts of heat to be released and the reaction to run away, is prevented by using a specially activated AlCl.sub.3, which has been activated by means of a metal halide selected from the group consisting of NaF.nHF with 0&lt;n.ltoreq.2, AgCl and FeCl.sub.3. In addition to it being considerably easier to control the reaction, shorter reaction times for the rearrangement and a decrease in the amount of by-products which are formed, are observed.

Chlorofluoro (hydro) carbon conversion process

Method for the manufacturing of alkali monofluorophosphate

A method of using rubber, preferably from tire recycling, for absorbing organic carboxylic acids containing from 1 to 3 carbon atoms optionally substituted with from 1 to 5 halogen atoms. Trifluoroacetic acid, for example, can be absorbed very effectively.

Sorption of carboxylic acids by means of rubber

A process for preparing fluorine-containing ethane derivatives using hydrogen fluoride and a catalytically active formulation comprising a tantalum fluorosulfonate compound or a niobium fluorosulfonate compound is described. The process is particularly suitable for preparing ethane derivatives which contain a CF.sub.3 group, for example for preparing C.sub.3 CHCl.sub.2 (R123) from perchloroethylene.

Process for preparing fluorine-containing ethane derivatives

A method of preparing fluorine-containing ethane derivatives using a catalyst mixture which comprises a metal halide and a sulfonic acid derivative is described. The method is particularly well suited for preparing CF.sub.3 CHCl.sub.2 (R123) from perchloroethylene and for preparing CF.sub.3 CH.sub.2 F (R134a) from trifluoroethylene.

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Hanover, Germany

Hans-Walter Swidersky