Recovery of Vanadium and Copper Catalysts
from adipic acid production
Adipic acid (ADA) is one of the top 50 organic chemicals in the world and is primarily consumed for the production of Nylon 6,6, polyamide fibers and resins. Traditionally, ADA is made by hydrogenation of phenol to cyclophexanol or by oxidation of cyclohexane to a mixture of cyclohexanone and cyclophexanol (also known as KA oil) in the presence of a cobalt or a boric acid catalyst.
The cyclophexanol or KA oil is further oxidized to adipic acid with nitric acid in the presence of copper and vanadium salts as catalysts. Crude ADA is crystallized and purified from the oxidation reaction solution. After crystallization, the waste mother liquor comprises an aqueous nitric acid solution containing copper and vanadium along with dicarboxylic acid by-products. Catalyst and nitric acid are recovered and recycled, organic acid by-products are used for the production of polyester polyols which are consumed in the polyurethane production.
The valuable copper and vanadium catalysts are removed from the waste mother
liquor by passing through a cation exchange resin bed. These metals are
then recovered by passing nitric acid through the spent cation exchange
resin during the ion exchange resin regeneration. The concentrated metal-containing
nitric acid solution can be then sent back to the oxidation reactor.
Recommended catalyst
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Macroporous polystyrenic strongly acidic resin. High capacity, resistant to oxidation and excellent stability. |
For sampling, pricing and availability of AMBERLYST™ catalysts please contact your Rohm and Haas sales representative.
