System and method of producing bisphenol-A (BPA) using two stage crystallization
First Claim
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1. A method of producing Bisphenol-A, comprising the steps of:
- reacting Phenol and Acetone in the presence of a catalyst to form a product solution including at least Bisphenol-A and Phenol, and where the Bisphenol-A, Phenol and a solvent exhibit a phase equilibrium relationship between the components of the product solution such that they exhibit compartments represented by a projection of a polythermal ternary phase diagram where Bisphenol-A and an adduct of Bisphenol-A and Phenol can crystallize respectively;
providing the solvent in said product solution, wherein said solvent is comprised of Acetone, Water or a mixture of Acetone and Water;
crystallizing an adduct of Bisphenol-A and Phenol from a first crystallization stage at a first selective composition of a feed stream to an adduct crystallizer stage such that the adduct is formed;
dissolving the adduct in a solvent having a selective composition; and
crystallizing substantially pure solid Bisphenol-A in a second crystallization stage at a second selective composition of a feed stream to a Bisphenol-A crystallizer stage such that the substantially pure Bisphenol-A is crystallized.
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Abstract
A system and method are provided wherein the phase equilibrium of a system comprised of Phenol, Bisphenol-A and a solvent mixture comprising Acetone and Water is selectively controlled such that either crystalline Bisphenol-A, or an adduct of Bisphenol-A and Phenol is crystallized from the product solution. The present invention provides for the recovery of pure Bisphenol-A (BPA) by direct crystallization from solution.
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23 Claims
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1. A method of producing Bisphenol-A, comprising the steps of:
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reacting Phenol and Acetone in the presence of a catalyst to form a product solution including at least Bisphenol-A and Phenol, and where the Bisphenol-A, Phenol and a solvent exhibit a phase equilibrium relationship between the components of the product solution such that they exhibit compartments represented by a projection of a polythermal ternary phase diagram where Bisphenol-A and an adduct of Bisphenol-A and Phenol can crystallize respectively;
providing the solvent in said product solution, wherein said solvent is comprised of Acetone, Water or a mixture of Acetone and Water;
crystallizing an adduct of Bisphenol-A and Phenol from a first crystallization stage at a first selective composition of a feed stream to an adduct crystallizer stage such that the adduct is formed;
dissolving the adduct in a solvent having a selective composition; and
crystallizing substantially pure solid Bisphenol-A in a second crystallization stage at a second selective composition of a feed stream to a Bisphenol-A crystallizer stage such that the substantially pure Bisphenol-A is crystallized. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of recovering Bisphenol-A solid from an adduct of Bisphenol-A and Phenol, comprising the steps of:
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dissolving the adduct in a solvent to form a feed solution; and
crystallizing Bisphenol-A from the feed solution wherein the composition of the feed solution and the temperature of the crystallizing step are selected such that substantially pure Bisphenol-A solid is crystallized.
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17. A method of producing solid Bisphenol-A from a product solution, characterized in that the product solution includes components that exhibit a phase equilibrium relationship they define phase compartments represented by a projection of a polythermal ternary phase diagram, where Bisphenol-A and an adduct of Bisphenol-A and Phenol can crystallize respectively;
- and the composition of the product stream is selected to be within the Bisphenol-A phase compartment such that substantially pure solid Bisphenol-A is formed upon crystallization.
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18. A system for producing Bisphenol-A comprising:
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a reactor unit wherein a product stream is produced including at least Bisphenol-A and Phenol;
a first stage crystallizer, the composition of the product stream fed to the first stage crystallizer being selectively adjusted such that an adduct of Bisphenol-A and Phenol is produced upon crystallization in the first stage crystallizer;
a dissolution tank where the adduct of Bisphenol-A and Phenol is dissolved in the product stream; and
a second stage crystallizer, the second stage crystallizer receiving the product stream and the composition of the product stream is selectively adjusted such that substantially pure Bisphenol-A is produced upon crystallization in the second stage crystallizer. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification