Phosphoric acid purification
AssigneeAlbright & Wilson Limited
InventorsRobert Harry Edwards, Thomas Alan Williams, Kenneth Hall
Life of this patent
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Abstract
A solid anhydrous 1:1 molar compound of phosphoric acid and diisopropyl ether is prepared from a mixture of the ether and phosphoric acid in a molar ratio (R:1) of 0.6:1 to 1.4:1 at a temperature at least as low as the crystallization temperature (T.degree.C) governed by the relationship T = 25(1.2-R). Treatment of the compound with water or a base produces purified acid or a phosphate respectively.
Claims25
A process for preparing an anhydrous crystalline compound of phosphoric acid and diisopropyl ether having the formula H.sub.3 PO.sub.4.sup.. [(CH.sub.3).sub.2 CH].sub.2 0, comprising mixing aqueous wet process phosphoric acid of 65-85 percent acidity with diisopropyl ether to produce an aqueous phase, and an organic phase which is a mixture of said ether and phosphoric acid in a molar proportion (R:1) of 0.6:1 to 1.4:1 and an amount of water of up to 1 mole water per mole of phosphoric acid, separating said aqueous phase from said organic phase, and forming crystals of said compound from said mixture at a temperature which is at least as low as the crystallization temperature T in degrees Centigrade which is determined by the relationship T=25(1.2-R), and separating said crystals.
A process for preparing an anhydrous crystalline compound of phosphoric acid and diisopropyl ether having the formula H.sub.3 PO.sub.4.sup.. [(CH.sub.3).sub.2 CH].sub.2 0, comprising mixing aqueous wet process phosphoric acid of 65-85 percent acidity with diisopropyl ether to form an organic phase and an aqueous phase, separating said aqueous phase from said organic phase and heating said organic phase to at least 45.degree. C to produce a diisopropyl ether phase, and an acid enriched organic phase which is a mixture of said ether and phosphoric acid in a molar proportion (R:1) of 0.6:1 to 1.4:1 and an amount of water of up to 1 mole water per mole of phosphoric acid, separating said ether phase from said mixture, and cooling said mixture to a temperature at least as low as the crystallization temperature T in degrees Centigrade at which crystals of said compound are formed and which is determined by the relationship T=25(1.2-R) to form crystals of said compound, and separating said crystals.
A process for preparing an anhydrous crystalline compound of phosphoric acid and diisopropyl ether having the formula H.sub.3 PO.sub.4.sup.. [(CH.sub.3).sub.2 CH].sub.2 0, comprising mixing aqueous wet process phosphoric acid of 65-85 percent acidity with diisopropyl ether to form an organic phase and an aqueous phase separating said aqueous phase from said organic phase and evaporating the ether from said organic phase to form a mixture of said ether, phosphoric acid and water in a molar proportion (R:1) of 0.6:1 to 1.4 and an amount of water of up to 1 mole per mole of phosphoric acid, and cooling said mixture to a temperature at least as low as the crystallization temperature T in degrees Centigrade at which crystals of said compound are formed and which is determined by the relationship T=25(1.2-R) to form crystals of said compound, and separating said crystals.
A process for preparing a phosphorus compound selected from the group consisting of phosphoric acid and phosphates which comprises treating the compound of formula H.sub.3 PO.sub.4.sup.. [(CH.sub.3).sub.2 CH].sub.2 O with a basic compound selected from the group consisting of water, ammonia, and an oxide, hydroxide, carbonate, bicarbonate, tribasic phosphate and dibasic phosphate of an alkali metal or alkaline earth metal.
Dependencies are inferred from the claim text.