The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 20, 1993
Filed:
Sep. 06, 1991
Applicant:
Inventor:
Jisuke Hayashi, Sapporo, JP;
Assignee:
DIC-Hercules Chemicals, Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08B / ; C07H / ; A61K / ;
U.S. Cl.
CPC ...
536 20 ; 536 553 ;
Abstract
There is disclosed a process for preparing a sulfonated chitosan wherein C3/C6-position hydroxyl groups are selectively sulfonated with inexpensive sulfonating agents which comprises dissolving or swelling chitosan in an acetic acid in water, regenerating chitosan with an alkaline aqueous solution, washing the regenerated chitosan with water and then with alcohol, immersing the chitosan in a polar solvent and pressing the solvent out of the same and sulfonating the chitosan with SO.sub.3 -DMF complex or ClHSO.sub.3an -DMF complex in a non-polar solvent. Separation of the product can be easily effected by way of filtration and the like.