Purification of bisphenol-A
First Claim
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1. A process for recovering bispenol-A in a purified state from water crystallized crude bisphenol-A which comprises the steps of:
- (a) mixing water-crystallized bisphenol-A in the presence of water with an organic solvent, said organic solvent being immiscible in water, lighter than water and a good solvent medium for impurities within crude bisphenol-A,(b) agitating the mixture,(c) forming three phases in the agitated mixture of step (b),(d) removing the top phase of the three phase mixture of step (c), and(e) separating purified bisphenol-A crystals from the remaining two phases of step (d).
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Abstract
A method for purifying bisphenol-A involving aqueous crystallization of impure bisphenol-A followed by in-situ treatment of the water/bisphenol-A crystal slurry with an organic washing solvent is presented. The purified bisphenol-A is then either removed from the crystal slurry or melted so the purification process can be repeated before separating the purified bisphenol-A.
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6 Claims
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1. A process for recovering bispenol-A in a purified state from water crystallized crude bisphenol-A which comprises the steps of:
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(a) mixing water-crystallized bisphenol-A in the presence of water with an organic solvent, said organic solvent being immiscible in water, lighter than water and a good solvent medium for impurities within crude bisphenol-A, (b) agitating the mixture, (c) forming three phases in the agitated mixture of step (b), (d) removing the top phase of the three phase mixture of step (c), and (e) separating purified bisphenol-A crystals from the remaining two phases of step (d). - View Dependent Claims (2, 3)
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4. A process for recovering bisphenol-A in a highly purified state from water crystallized crude bisphenol-A which comprises the steps of:
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(a) mixing water-crystallized bisphenol-A in the presence of water with an organic solvent, said organic solvent being immiscible in water, lighter than water and a good solvent medium for impurities within crude bisphenol-A, (b) agitating the mixture, (c) forming three phases in the agitated mixture of step (b), (d) removing the top phase of the three phase mixture of step (c), (e) heating the remaining two phase crystal slurry of step (d) to a temperature sufficiently high to melt the bisphenol-A crystals within, (f) cooling the heated two phase crystal slurry of step (e) to a temperature sufficiently low to crystallize the molten bisphenol-A, (g) mixing a fresh organic solvent into the cooled two phase crystal slurry of step (f) said fresh organic solvent being immiscible with water, lighter than water and a good solvent medium for impurities within the bisphenol-A crystals, (h) agitating the mixture of step (g), (i) forming three phases in the agitated mixture of step (h), (j) removing the top phase of the three phase mixture of step (i), and (k) separating highly purified bisphenol-A crystals from the remaining two phases of step (j). - View Dependent Claims (5, 6)
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Specification