Process for the production of pure diglycolic acid by oxidation of diethylene glycol with nitric acid
AssigneeChemische Werke Huels Aktiengesellschaft
InventorManfred Schroeder
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Abstract
A process for the production of pure diglycolic acid by oxidation of diethylene glycol with nitric acid, comprises the steps of: A. cooling the reaction mixture formed during the oxidation to a temperature of -10.degree. to +25.degree. C. and separating a first quantity of thus-crystallized diglycolic acid; B. concentrating the first mother liquor at 5 - 530 millibars to a concentration of 35-45% by weight of HNO.sub.3 and cooling to a temperature of -10.degree. to +25.degree. C.; c. separating a further quantity of thus-crystallized diglycolic acid; and D. recycling the remaining second mother liquor to the reactor for oxidizing diethylene glycol with nitric acid.
Claims9
In a process for the production of pure diglycolic acid by oxidation of diethylene glycol with nitric acid in a reaction zone to form a reaction mixture containing diglycolic acid, the improvement comprising:
- a. cooling at least a portion of the reaction mixture to -10.degree. to +25.degree. C. to crystallize a portion of the diglycolic acid therein;
- b. separating the crystallized diglycolic acid from the cooled reaction mixture;
- c. concentrating the resultant mother liquor at 5-530 mb. to a nitric acid concentration of 35-45% by weight;
- d. cooling the concentrated mother liquor to -10.degree. to +25.degree. C. to crystallize a second portion of diglycolic acid;
- e. separating the second portion of crystallized diglycolic acid from the cooled mother liquor;
- and
- f. recycling the mother liquor to the reaction zone for oxidation of diethylene glycol with nitric acid.
Dependencies are inferred from the claim text.