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公开(公告)号：DE4025937A1
公开(公告)日：1992-02-20
申请号：DE4025937
申请日：1990-08-16
Applicant: HOECHST AG
IPC: C01B7/03 , C01B25/163
Abstract: In a continuous process for the preparation of phosphorous acid with simultaneous production of hydrochloric acid, a reaction zone is provided which is in open communication with a first scrubbing zone. A portion of the reaction product is recycled from the bottom of the reaction zone into the top of the scrubbing zone and phosphorous acid is removed from the circulation. Hydrogen chloride gas escaping from the top of the first scrubbing zone is brought into contact, in a cooled, second scrubbing zone, with an overstoichiometric amount of water. Hydrochloric acid is obtained which is passed as starting material into the reaction zone or into the top of the first scrubbing zone. The external cooling of the second scrubbing zone is controlled such that the temperature in the reaction zone is kept constant at a desired value between 90 DEG and 130 DEG C. without adding any external cooling or heating energy. Pure hydrochloric acid is recovered in an absorption zone.
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公开(公告)号：DE4323527A1
公开(公告)日：1995-01-19
申请号：DE4323527
申请日：1993-07-14
Applicant: HOECHST AG
Abstract: The present invention relates to a process for preparing crystalline sodium disilicate having a seat structure (layer structure) and a molar ratio of SiO2/Na2O of (1.8 to 2.2) : 1 in a pure delta phase from a waterglass solution having a molar ratio of SiO2/Na2O of (1.8 to 2.2) : 1 or an amorphous, water-containing sodium disilicate as starting material, which is characterized in that the starting material contains from 1 to 99 % by weight of water and is heated by microwave radiation in a heat-insulated reaction zone to from 400 to 800 DEG C.
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公开(公告)号：DE4210253A1
公开(公告)日：1993-09-30
申请号：DE4210253
申请日：1992-03-28
Applicant: HOECHST AG
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公开(公告)号：DE4107231A1
公开(公告)日：1992-09-10
申请号：DE4107231
申请日：1991-03-07
Applicant: HOECHST AG
Inventor： SCHIMMEL GUENTHER DIPL CHEM DR , KOTZIAN MICHAEL DIPL CHEM DR , TAPPER ALEXANDER DIPL CHEM DR , WINGEFELD GERD DIPL CHEM DR
IPC: C01B33/32
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公开(公告)号：DE4435568A1
公开(公告)日：1996-04-11
申请号：DE4435568
申请日：1994-10-05
Applicant: HOECHST AG
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Patent Agency Ranking
公开(公告)号：DE4216783A1
公开(公告)日：1993-11-25
申请号：DE4216783
申请日：1992-05-21
Applicant: HOECHST AG
Inventor： EYSMONDT JOERG VON DIPL CHEM D , RITTNER SIEGBERT DIPL CHEM DR , TAPPER ALEXANDER DIPL CHEM DR , HOLZ JOSEF DIPL ING , ELSNER GEORG DIPL CHEM DR
Abstract: Purifcn. of phosphorous acid (produced by halogenation of hydrocarbons, esp. chlorination of fatty acids, with phosphorus trihahdas) comprises: (a) passing the impure phosphorous acid in conc. form into a column; (b) treating the acid with hot water vapour (at 110-150 deg. C) with a residence time of 5-30 mins,; and (c) feeding the stripped acid which comes out of the column to a membrane module, under high pressure, and filtering it using tangential overflow at 20-90 deg. C. Pref. the impure phosphorous acid is a 40-90% aq. soln. or is an anhydrous melt. The column is a packed column. Prior to passing to the membrane module the phospherous acid is collected in a storage zone. The membrane module contains at least one temp. and acid resistant nanofiltration membrane. This is made of polyamide, polyaramide, polyimide, polyether ketone and/or polysulphone. Filtration is at 10-40 bar and 30-50 deg. C. USE/ADVANTAGE - The process can be carried out independent of the availability of technical appts. for prodn. of phosphoric- or phosphorous acids.
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公开(公告)号：DE4107230A1
公开(公告)日：1992-09-10
申请号：DE4107230
申请日：1991-03-07
Applicant: HOECHST AG
Inventor： SCHIMMEL GUENTHER DIPL CHEM DR , KOTZIAN MICHAEL DIPL CHEM DR , TAPPER ALEXANDER DIPL CHEM DR , WINGEFELD GERD DIPL CHEM DR
Abstract: For the preparation of crystalline sodium silicates having a layer structure, an SiO2/Na2O molar ratio of (1.9 to 2.1):1 and a water content of less than 0.3% by weight from a waterglass solution obtained by reacting sand with sodium hydroxide solution in an SiO2/Na2O molar ratio of (2.0 to 2.3):1 and having a solids content of at least 20% by weight, the waterglass solution is treated in a spray-drying zone with hot air at 200 to 300 DEG C to form a pulverulent, amorphous sodium silicate having a water content (determined as loss on ignition at 700 DEG C) of 15 to 23% by weight. The pulverulent, amorphous, water-containing sodium silicate is first ground, preferably to grain sizes of 1 to 50 mu m, before it is introduced into a rotary kiln in an inclined arrangement and treated therein with flue gas in countercurrent at temperatures of more than 500 to 850 DEG C, to form crystalline sodium silicate. The sodium silicate emerging from the rotary kiln is first comminuted to grain sizes of 0.1 to 12 mm and finally ground to grain sizes of 2 to 400 mu m.
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公开(公告)号：DE19537957A1
公开(公告)日：1997-04-17
申请号：DE19537957
申请日：1995-10-12
Applicant: HOECHST AG
Abstract: Prodn. of highly-replaceable sodium disilicate (I) in beta -form and having an Na2O:SiO2 molar ratio of about 1:2 comprises: (a) treating a source of silicate with NaOH at an increased temp.; (b) filtering; and (c) removing the prod. formed. The novelty is that the prod. is post-tempered at 450-780 degrees C and/or compressed to give compact parts. Also claimed is (I) as above.
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公开(公告)号：DE4107230C2
公开(公告)日：1995-04-06
申请号：DE4107230
申请日：1991-03-07
Applicant: HOECHST AG
Inventor： SCHIMMEL GUENTHER DIPL CHEM DR , KOTZIAN MICHAEL DIPL CHEM DR , TAPPER ALEXANDER DIPL CHEM DR , WINGEFELD GERD DIPL CHEM DR
Abstract: For the preparation of crystalline sodium silicates having a layer structure, an SiO2/Na2O molar ratio of (1.9 to 2.1):1 and a water content of less than 0.3% by weight from a waterglass solution obtained by reacting sand with sodium hydroxide solution in an SiO2/Na2O molar ratio of (2.0 to 2.3):1 and having a solids content of at least 20% by weight, the waterglass solution is treated in a spray-drying zone with hot air at 200 to 300 DEG C to form a pulverulent, amorphous sodium silicate having a water content (determined as loss on ignition at 700 DEG C) of 15 to 23% by weight. The pulverulent, amorphous, water-containing sodium silicate is first ground, preferably to grain sizes of 1 to 50 mu m, before it is introduced into a rotary kiln in an inclined arrangement and treated therein with flue gas in countercurrent at temperatures of more than 500 to 850 DEG C, to form crystalline sodium silicate. The sodium silicate emerging from the rotary kiln is first comminuted to grain sizes of 0.1 to 12 mm and finally ground to grain sizes of 2 to 400 mu m.
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公开(公告)号：DE4318242A1
公开(公告)日：1994-12-08
申请号：DE4318242
申请日：1993-06-02
Applicant: HOECHST AG
Abstract: The present invention relates to a process for preparing a crystalline sodium sheet (layer) silicate having a kanemite structure of the chemical formula NaH Si2O5 . X H2O where X has a value between 1 and 3, which is characterised in that sodium disilicate, silica and water are mixed in a molar ratio of 1:2:(6-8) and are held at a temperature of from 20 to 100@C for a period of from 0.2 to 10 hours.
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