Washing system for nitroaromatic compounds
AssigneeNoram International Limited
InventorSergio Berretta
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Abstract
A method of removing alkalinity and salt from a nitroaromatic product downstream of water washing to remove mineral acids and alkaline washing to remove salts of organic acids, comprises washing the product stream with an acidic aqueous solution, prior to the step of removing excess organic reactant, by steam stripping or distillation. Acid removed from the stripper or column is recycled back for use in the acidic washing. The acidic washing is done instead of the neutral washing step of the prior art. It removes residual salt and decreases the level of entrained colloidal water in the nitroaromatic product.
Claims35
A method of removing impurities from a product stream comprising a nitroaromatic product, comprising the steps of:
- (a) alkaline washing the nitroaromatic product stream to remove acidic organic by-products;
- and
- (b) washing the nitroaromatic product stream from step (a) with an acidic aqueous solution.
A method of removing impurities from a product stream comprising a nitroaromatic product, comprising the steps of:
- (a) washing the nitroaromatic product stream with water to remove mineral acids;
- (b) washing the nitroaromatic product stream from step (a) with an acidic aqueous solution to remove hydrophilic acids;
- and
- (c) removing residual organic reactant from the nitroaromatic product stream from step (b) by one of steam stripping and distillation.
Dependencies are inferred from the claim text.