Method of purifying nitrated aromatic compounds from a nitration process
AssigneeNoram International Limited
InventorsSteven D. Buchi, Alfred A. Guenkel
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Abstract
A process for removing impurities from crude nitrated aromatic products obtained during the nitration of aromatic compounds. The nitrated aromatic products are purified by treatment with ammonia washing followed by caustic washing. The nitrophenolic-containing wash waters are treated to recover dissolved organics and ammonia, and the stripped ammonia-wash effluent is incinerated. Carbon dioxide, which can accumulate in the process, is purged to the caustic washer.
Claims28
A method of purifying a nitroaromatic product containing nitro-hydroxy-aromatic by-products produced in a nitration process, comprising the steps of:
- (a) washing the nitrated aromatic product containing nitro-hydroxy-aromatic by-products with an alkaline aqueous solution comprising ammonia to convert some of the nitro-hydroxy-aromatic by-products into their respective nitro-hydroxy-aromatic ammonium salts;
- (b) separating an aqueous wash stream containing the nitro-hydroxy-aromatic ammonium salts formed in step (a) from an organic stream comprising ammonia-washed nitroaromatic product;
- (c) washing the ammonia-washed nitroaromatic product with an aqueous alkali metal hydroxide solution to convert the nitro-hydroxy-aromatic by-products that were not removed in steps (a) and (b) into their respective nitro-hydroxy-aromatic alkali-metal salts;
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- (d) separating an aqueous wash stream comprising the nitro-hydroxy-aromatic alkali-metal salts produced in step (c) from an organic stream comprising alkali-metal-hydroxide-washed nitroaromatic product.
A method of purifying a nitroaromatic product containing nitro-hydroxy-aromatic by-products produced in a nitration process, comprising the steps of:
- (a) washing the nitrated aromatic product containing nitro-hydroxy-aromatic by-products with an alkaline aqueous solution comprising ammonia to convert some of the nitro-hydroxy-aromatic by-products into their respective nitro-hydroxy-aromatic ammonium salts;
- (b) separating an aqueous wash stream containing the nitro-hydroxy-aromatic ammonium salts formed in step (a) from an organic stream comprising ammonia-washed nitroaromatic product;
- (c) washing the ammonia-washed nitroaromatic product with an aqueous solution comprising a base stronger than ammonia to convert the nitro-hydroxy-aromatic by-products that were not removed in steps (a) and (b) into their respective nitro-hydroxy-aromatic salts;
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- (d) separating an aqueous wash stream comprising the nitro-hydroxy-aromatic salts produced in step (c) from an organic stream comprising washed nitroaromatic product.
Dependencies are inferred from the claim text.