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US 6,712,946 B2Granted
Electrodialysis of multivalent metal salts
AssigneeThe Electrosynthesis Company, Inc.
InventorsJ. David Genders, Dan Hartsough
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Abstract
A method for electrodialysis is conducted in a multi-compartment, preferably a four compartment, electrodialysis cell configuration wherein an inexpensive source of protons, preferably from a strong inorganic acid enables the conversion of multivalent metal salts into valuable acid products, such as 2-keto-L-gluconic acid, a vitamin C precursor, and useful by-products, like calcium chloride.
Claims8
A method for preparing 2-keto-L-gulonic acid in a multi-compartment electrodialysis cell, which comprises the steps of:
- (i) introducing a first feed solution into a first feed compartment of said electrodialysis cell, said first feed solution comprising a multivalent metal salt of a gluconic acid derivative from a fermentation process;
- (ii) introducing a second feed solution into a second feed compartment of said electrodialysis cell, said second feed solution comprising an acid suitable for providing protons and anions that form soluble salt by-products with the multivalent metal from said multivalent metal salt of the gluconic acid derivative;
- (iii) transporting anions from said metal salt of the gluconic acid derivative in said first feed compartment across an anion exchange membrane and into an acid product compartment;
- (iv) forming the 2-keto-L-gulonic acid from the anions of said metal salt of the gluconic acid derivative in said acid product compartment by the introduction of said protons from across a cation exchange membrane in the second feed compartment, and
- (v) forming said soluble salt by-product by transporting multivalent cations from said multivalent metal salt of the gluconic acid derivative in the first feed compartment across a cation exchange membrane and with anions of the acid transported across an anion exchange membrane from said second feed compartment.
2 more elements
Dependencies are inferred from the claim text.