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    2.
    发明专利
    未知

    公开(公告)号：DE4411681A1

    公开(公告)日：1995-10-12

    申请号：DE4411681

    申请日：1994-04-05

    Applicant: HOECHST AG

    Inventor： DOENGES REINHARD DR ,  HILBIG JOSEF DR

    IPC: C08B11/00 ,  C08B11/20 ,  C08B31/08 ,  C08B37/00 ,  C08B11/02

    Abstract: The prodn. of low-mol. wt. polysaccharide ether (I) by oxidative degradation of high-mol. wt. polysaccharide ether (II) comprises adding a perborate (III) or a mixt. of (III) and perborate activator (IV) to a slurry or suspension of (II) and reacting at 25-90 deg. C.

    3.
    发明专利
    未知

    公开(公告)号：DE3903797A1

    公开(公告)日：1990-08-16

    申请号：DE3903797

    申请日：1989-02-09

    Applicant: HOECHST AG

    Inventor： MEISTER CHRISTOPH DR ,  DOENGES REINHARD DR

    IPC: C08B37/08

    Abstract: The invention relates to a process for the preparation of activated chitosans in which a chitosan is reacted with an acid to form a salt and preferably subsequently with a base. The addition of acid and, preferably, of base in the activation is carried out in a suspending agent which substantially prevents dissolution of the chitosan salts. Suspending agents which can be used are both aqueous solutions of inorganic salts and organic or aqueous-organic solvents. The invention also relates to a process for preparing both water-soluble and water-insoluble chitosan derivatives by reacting the activated chitosans with reagents which are generally suitable for reacting polysaccharides or amines.

    7.
    发明专利
    未知

    公开(公告)号：BR9401296A

    公开(公告)日：1994-11-01

    申请号：BR9401296

    申请日：1994-03-25

    Applicant: HOECHST AG

    Inventor： DOENGES REINHARD DR ,  REICHEL DIETHART DR ,  KESSLER BIRGIT

    IPC: C08B37/08 ,  F26B3/12 ,  F26B17/28

    Abstract: The present invention relates to a process for the preparation and workup of N-hydroxyalkylchitosans which are soluble in aqueous medium, comprising the measures of dispersion of chitosan in an aqueous medium, subsequent hydroxyalkylation of the dispersed chitosan and subsequent workup of the N-hydroxyalkylchitosan, which is characterised in that the hydroxyalkylation is carried out up to an average degree of substitution (DS) of 2.0, preferably 1.5 to 2.0, after the hydroxyalkylation and before the workup a part of the aqueous medium is removed where appropriate, and the workup of the N-hydroxyalkylchitosan takes place by drying.

    8.
    发明专利
    未知

    公开(公告)号：DE59005566D1

    公开(公告)日：1994-06-09

    申请号：DE59005566

    申请日：1990-02-06

    Applicant: HOECHST AG

    Inventor： MEISTER CHRISTOPH DR ,  DOENGES REINHARD DR

    IPC: C08B37/08

    Abstract: The invention relates to a process for the preparation of activated chitosans in which a chitosan is reacted with an acid to form a salt and preferably subsequently with a base. The addition of acid and, preferably, of base in the activation is carried out in a suspending agent which substantially prevents dissolution of the chitosan salts. Suspending agents which can be used are both aqueous solutions of inorganic salts and organic or aqueous-organic solvents. The invention also relates to a process for preparing both water-soluble and water-insoluble chitosan derivatives by reacting the activated chitosans with reagents which are generally suitable for reacting polysaccharides or amines.

    Purification of cellulose ether(s) from suspension - by sepn. and purification on sequential pressure filter
    9.
    发明专利
    Purification of cellulose ether(s) from suspension - by sepn. and purification on sequential pressure filter 未知

    公开(公告)号：DE4112849A1

    公开(公告)日：1991-10-31

    申请号：DE4112849

    申请日：1991-04-19

    Applicant: HOECHST AG

    Inventor： ARNDT HORST ,  BUCHBERGER GERHARD DIPL ING ,  DOENGES REINHARD DR ,  SPONHEIMER MANFRED DIPL ING ,  WELT GUENTHER DR

    IPC: C08B11/20 ,  C08B11/22

    Abstract: A process for sepg. cellulose ethers (I) from suspensions of (I) and purifying the sepd. (I) is carried out with the aid of a sequential pressure filter. The suspension is an aq. suspension or a suspension contg. organic solvent (II); (I) is purified with an aq. or solvent-contg. wash liq. (opt with a solvent other than (II)), pref. in several stages; purificn. is carried out with a liq. from previous purificn. of another batch of prod., which contains, but is not satd. with salts or by-prods.; the filter cake is treated with steam after each sepn. or purificn. stage; sepn. and purificn. are carried out at 10-150 (pref. 60-120) deg.C under pressure; moisture is removed from the filter cake by passing in air or nitrogen; the pressure filter has several chambers in which the direction of filtration is constantly reversed every time the chamber is loaded with the next batch of prod. on the moving belt. USE/ADVANTAGE - Provides a process for the sepn. and purificn. of (I) obtd. in suspension by etherification of cellulose with, e.g. MeCl, EtCl, ethylene oxide, etc.; it enables sepn. and purificn. of (I) with a high coagulation pt. without blocking the filter medium and without high prod. losses due to cleaning the filter medium or to prod. coming through the filter.

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