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公开(公告)号：DE3115197A1
公开(公告)日：1982-11-11
申请号：DE3115197
申请日：1981-04-15
Applicant: BASF AG
Abstract: Low-fuming, free-flowing fluxes for sherardising contain from 50 to 90% by weight of alkali metal chlorides and from 10 to 50% by weight of ammonium chloride. In addition they contain, based on the ammonium chloride and alkali metal chloride content, from 0.1 to 1% by weight of magnesium oxide and so much zinc chloride, that the weight ratio of magnesium oxide to zinc chloride is from 1 : 2 to 1 : 10.
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Patent Agency Ranking
公开(公告)号：DE2915792A1
公开(公告)日：1980-10-30
申请号：DE2915792
申请日：1979-04-19
Applicant: BASF AG
Inventor： LUKAS SIEGMAR DIPL CHEM DR , TREIBER GERT DIPL CHEM DR , SCHREINER SIEGFRIED DIPL CHEM , VOELKL ERFRIED DIPL CHEM DR , APPL MAX DIPL CHEM DR
IPC: C01B17/66
Abstract: Dust-free dithionites, esp. Na2S2O4, are prepd. by mixing the dithionites with 0.1-3 (esp. 0.2-0.7) wt.% polypropylene oxides having mol. wt. 50-1200. Dithionites are used as bleaching agents in textiles-, pulp- and paper industry and as reducing agents for vat dyes. Dithionites are stabilised against decompsn. by moisture and air-O2 and can be compacted by pressing. Dust-formation and handling is prevented. The prods. dissolve in water and do not foam when dissolved in dye-baths with stirring.
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公开(公告)号：DE2908414A1
公开(公告)日：1980-09-11
申请号：DE2908414
申请日：1979-03-03
Applicant: BASF AG
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公开(公告)号：DE2703282A1
公开(公告)日：1978-08-10
申请号：DE2703282
申请日：1977-01-27
Applicant: BASF AG
Inventor： KIENER VOLKER DIPL CHEM DR , AUTZEN HORST DIPL CHEM DR , KOESTER HARTWIG DIPL CHEM DR , WUNSCH GERD DIPL CHEM DR , OSTERTAG WERNER DIPL CHEM DR , SCHREINER SIEGFRIED DIPL CHEM , VOELKL ERFRIED DIPL CHEM DR , HETZEL ECKARD DIPL CHEM
IPC: C01B17/66
Abstract: Anhydrous sodium dithionite is prepd. by the action of SO2 on NaOOCH in excess and NaOH in a reaction medium formed of H2O and an organic solvent. Methyl formate is also added to the reaction mixt. in a proportion which is =15 wt. % w.r.t. the organic solvent, and pref. when the reaction mixt. contains >=66% of the theoretical amt. of SO2 to be used. The molar proportions of NaOH and SO2 do not exceed the ratio 1:2. The process gives increased yields of a purer and more stable sodium dithionite, with a better granules size distribution. Pref. the initial reaction mixt. contains all the NaOH required in the form of an aq. soln., possibly contg. a part of the NaOOCH and/or the SO2. The remaining NaOOCH and SO2, as well as the cH3OOCH, are then added to this initial reaction mixt.
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公开(公告)号：DE2646825A1
公开(公告)日：1978-04-20
申请号：DE2646825
申请日：1976-10-16
Applicant: BASF AG
Inventor： LEUTNER BERND DIPL CHEM DR , CSIZI GOTTHARD DIPL CHEM DR , LUKAS SIEGMAR DIPL CHEM DR , SCHREINER SIEGFRIED DIPL CHEM , VOELKL ERFRIED DIPL CHEM DR
Abstract: Concentrated dithionite solutions are produced by cathodic reduction of an aqueous solution, containing sulfite and/or bisulfite, which is circulated by pumping. The cathode and anode chambers are separated from one another by a permselective cation exchanger membrane. The catholyte must be circulated at least 10 times per hour and the selective catholyte volume outside the cell, defined as a = Vtotal -VC/Vtotal, SHOULD BE LESS THAN 0.9.
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