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ApplicationNo. 256882 filed on 07/28/1994
US Classes:510/471, Containing carboxyl group or salt thereof (e.g., carboxymethyl cellulose, etc.)510/361, Polycarboxylic acid component, or acid anhydride or salt thereof (e.g., sodium citrate, maleic anhydride polymer, polyacrylic acid, etc.)510/532, Aluminum or boron containing metal silicate component (e.g., aluminosilicate, zeolite, etc.)510/533, Polycarboxylic acid component, or salt thereof (e.g., nitrilotriacetic acid, polyacrylic acid, etc.)536/97, Carboxyalkyl or salts thereof536/104, Aldehyde reaction product536/105, Oxidized starch or derivative536/120, Ethers536/124Processes
ExaminersPrimary: Kight, III, John
Assistant: Leary, Louise N.
Attorney, Agent or Firm
Foreign Patent References
International ClassesC07G 017/00
Foreign Application Priority Data1992-02-11 DE
AbstractA process for the production of polycarboxylic acids or salts thereof from polysaccharides by oxidation with nitrogen dioxide/dinitrogen tetroxide with at least partial conversion of the primary alcohol groups of the polysaccharides into carboxyl groups and optionally at least partial neutralization of the carboxylic acid groups formed is provided. The oxidation reaction is carried out in a closed reaction system in the presence of oxygen under pressures of 2 bar to 10 bar and at a temperature above room temperature. Nitrogen dioxide/dinitrogen tetroxide is used in such quantities that, in the event of a theoretically complete shift of the equilibrium onto the nitrogen dioxide side, the nitrogen dioxide is present in quantities of at most 2 mole equivalents, based on the content of monomer unit of the polysaccharide containing one primary alcohol group.