Fluidized-bed oxidation process for the production of polysaccharide-based polycarboxylates
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorsKonrad Engelskirchen, Herbert Fischer, Werner Juettner, Hans-Wilhelm Verholt, Thomas Moeller
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Abstract
A process for producing polycarboxylic acids or their salts from polysaccharides is provided. Solid particulate polysaccharides having at least one primary alcohol group in the polysaccharides are oxidized with nitrogen dioxide in a fluid bed. The fluidizing gas contains nitrogen dioxide and the process is operated at a pressure of from 0.5 to 12 bars and a temperature between the boiling point of nitrogen dioxide and 160.degree. C. At least two moles of nitrogen dioxide for the equivalent of the primary alcohol groups reacted over the entire reaction are provided.
Claims20
In a process for the production of polycarboxylic acids from polysaccharides by conversion of at least part of the primary alcohol groups of the polysaccharides into carboxyl groups under a pressure of 0.5 bar to 12 bar and at a temperature in the range from the boiling point of the nitrogen dioxide under the particular pressure to 160.degree. C. the improvement which comprises:
- contacting a particulate polysaccharide in a fluidized bed with a gas fluidizing medium containing nitrogen dioxide wherein the nitrogen dioxide is present in a quantity of at least 3 mole equivalents, based on an equivalent of alcohol groups oxidized and totalled over the reaction time.
Dependencies are inferred from the claim text.