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AssigneeOxolife, S.L.
InventorsAgnès Arbat Bugié, Rosa Torres Ferraz, Jordi Bessa Bellmunt, Abel Tamayo Haro, Ignacio Canals Almazán
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The present invention provides a process for preparing tungsten (VI) salts hydrates, the process comprising (a) Preparing a tungsten (VI) salt in an alkaline aqueous solution; (b) Filtering the aqueous solution at a temperature at which the tungsten (VI) salt remains dissolved; (c) Precipitating the tungsten (VI) salt hydrate from the filtrate resulting from step (b); (d) Filtering; (e) Washing the resulting filter cake with a water-miscible solvent; and (f) Drying the washed cake under conditions that allow the removal of the water-miscible solvent. The resulting salts show a level of impurities and solvents so low that they are suitable in the fields of pharmacy, veterinary and dietary.
A process for obtaining a tungsten (VI) salt hydrate, the process comprising:
The process according to any one of the preceding claims, wherein the tungsten (VI) salt hydrate comprises a cationic moiety selected from the group of cations:
The process of any one of the preceding claims, wherein the tungsten (VI) salt hydrate is dihydrate sodium tungstate.
The process of any one of the preceding claims, wherein step (a) is performed by dissolving a tungsten-containing compound selected from:
The process of any one of the preceding claims, wherein the alkaline aqueous solution further includes cationic moieties selected from sodium, ammonium, copper, potassium, magnesium, and calcium, zinc and silver.
The process of any one of the preceding claims, wherein step (a) is performed by heating to a temperature lower than the reflux temperature.
The process of any one of the preceding claims, wherein the filtering step (b) is performed at a temperature equal or above 30° C. but below the reflux temperature.
The process of any one of the preceding claims, wherein step (c) is performed by cooling or adding a water-miscible solvent.
The process of any one of the preceding claims, wherein the water-miscible solvent used in steps (c) and (e) comprises or consists (C1-C8)alkanol.
The process of any one of the preceding claims, wherein step (e) is repeated.
The process of any one of the preceding claims for obtaining Na2WO4·2H2O, the process comprising:
A pharmaceutical, veterinary or dietary sodium tungstate dihydrate comprising a water residual content from 10 to 15% by weight with respect to the total weight of the salt.
Dependencies are inferred from the claim text.