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Title:
PROCESS FOR PREPARING SOLUTIONS OF ANIONIC ORGANIC COMPOUNDS
Document Type and Number:
WIPO Patent Application WO2001090257
Kind Code:
A3
Abstract:
Described is a process for preparing concentrated solutions or suspensions of anionic organic compounds which comprises a) acidifying an aqueous solution or suspension of an anionic organic compound containing salts and/or impurities to a pH of 4.5 or less, if the pH is above this value, so that b) the anionic organic compound is water-insoluble and precipitates in the form of the free acid, c) bringing the suspension to a salt content below 2 % by weight, based on the total weight of the retentate, by means of ultrafiltration with a membrane having pore diameters of from 0.001 to 0.02 mu m, and d) optionally washing out the salts with water having a pH below 4,5, e) optionally carrying out acid-free washing with water thereafter, and then f) concentrating, so that the amount of anionic organic compound is 5-50 % by weight, and g) if desired, bringing the anionic organic compound into solution by adding an appropriate base.

Inventors:
MALISZ JACEK (DE)
KAESER ADOLF (CH)
KAUFEL RAINER (DE)
LAUTENBACH HOLGER (DE)
POLLEY ELKE (DE)
HOFFMANN MARTINA (DE)
Application Number:
EP0105796W
Publication Date:
April 04, 2002
Filing Date:
May 21, 2001
Export Citation:
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Assignee:
CIBA SPECIALTY CHEMICALS HOLDING INC.
MALISZ, JACEK
KAESER, ADOLF
KAUFEL, RAINER
LAUTENBACH, HOLGER
POLLEY, ELKE
HOFFMANN, MARTINA
International Classes:
C09B29/045; C09B29/52; C09B57/00; C09B67/00; C09B67/26; C09B67/44; C09B67/54; D21H21/30; (IPC1-7): C09B67/54
Domestic Patent References:
WO2001032786A12001-05-10
Foreign References:
EP0652044A11995-05-10
EP0992547A22000-04-12
EP0802240A21997-10-22
EP0278320A21988-08-17
EP0197006A21986-10-08
EP0049802A11982-04-21
EP0302015A21989-02-01
DE4108596A11991-09-26
EP0287515A11988-10-19
DE4116522A11991-11-28
EP0505870A11992-09-30
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