System and method of producing bisphenol-A (BPA)
First Claim
1. A method for producing bisphenol-A by crystallization from a product solution comprising the following steps:
- forming a product solution comprised of phenol, bisphenol-A, isomers of bisphenol-A, un-reacted reactants, and a solvent comprised of two or more solvent components, selectively controlling the amount of said solvent in the product solution to manipulate a phase behavior of the product solution such that a maximum amount of substantially pure crystalline bisphenol-A will be crystallized from said product solution before a solid adduct of bisphenol A and phenol appears, where the total weight percent of said solvents prior to crystallization is at or below about 40%, and separating substantially pure bisphenol-A, where the final separation of substantially pure bisphenol-A is achieved by direct crystallization.
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Abstract
A system and method for producing bisphenol-A (BPA) is provided. In particular, the present invention provides a system and method of producing bisphenol-A wherein the phase equilibrium behavior of a feed solution to a crystallizer is selectively controlled and adjusted to provide desired results. This provides a powerful tool, whereby certain operating conditions or variables of the bisphenol-A process can be selectively adjusted to generate desired phase equilibrium behavior. In general, bisphenol-A is produced from a reaction of phenol and acetone, forming a product solution including phenol, bisphenol-A, isomers of bisphenol-A, unreacted reactants and by-products. A solvent is provided in the product solution and the amount and composition of solvent in the product solution are selectively controlled to adjust the composition of the product solution fed to a crystallizer such that either crystalline bisphenol-A, or an adduct of bisphenol-A and phenol is crystallized from the product solution. Thus, a solvent is used to selectively control the phase behavior of the system. The solvent is a pseudo component and may be comprised of a single component or may be comprised of a solvent mixture of two or more solvents each exhibiting certain phase behavior in the system.
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Citations
21 Claims
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1. A method for producing bisphenol-A by crystallization from a product solution comprising the following steps:
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forming a product solution comprised of phenol, bisphenol-A, isomers of bisphenol-A, un-reacted reactants, and a solvent comprised of two or more solvent components, selectively controlling the amount of said solvent in the product solution to manipulate a phase behavior of the product solution such that a maximum amount of substantially pure crystalline bisphenol-A will be crystallized from said product solution before a solid adduct of bisphenol A and phenol appears, where the total weight percent of said solvents prior to crystallization is at or below about 40%, and separating substantially pure bisphenol-A, where the final separation of substantially pure bisphenol-A is achieved by direct crystallization. - View Dependent Claims (2, 3, 4, 18)
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5. A method for producing bisphenol-A by crystallization from a product solution comprising the following steps:
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forming a product solution from a reaction comprised of phenol, bisphenol-A, isomers of bisphenol-A, un-reacted reactants, and a solvent comprised of two or more solvent components, where the bisphenol-A, phenol and solvent exhibit a phase equilibrium relationship represented by a projection of a polythermal ternary phase diagram having a total defined area and at least two regions in the phase diagram, an adduct region and a pure solid bisphenol-A region, where one of said solvent components exhibits a first phase behavior and the other of said solvent components exhibits a second phase behavior, and selectively controlling the concentration ratio of said solvent components in the product solution during crystallization, to produce a phase behavior such that substantially pure solid bisphenol-A will be crystallized from said product solution, where the total weight percent of said solvents prior to crystallization is less than about 40%, separating substantially pure bisphenol-A, where the final separation of substantially pure bisphenol-A is achieved by direct crystallization. - View Dependent Claims (6, 7, 8, 9, 10, 11, 19)
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12. A method of producing bisphenol-A by crystallization, comprising the following steps:
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reacting phenol and acetone in the presence of a catalyst to form a product solution including bisphenol-A, phenol and solvent, where the bisphenol-A, phenol and solvent exhibit a phase equilibrium relationship represented by a projection of a polythermal ternary phase diagram;
providing two or more solvent components in said product solution, where one of said solvent components exhibits a first phase behavior and the other of said solvent components exhibits a second phase behavior, where the total solvent concentration is at or below about 40 weight percent; and
adjusting the concentration ratio of the solvent components in the product solution to control the phase behavior of the product solution to selectively form substantially pure solid bisphenol-A from said product solution during crystallization, where the final separation of substantially pure bisphenol-A is achieved by direct crystallization. - View Dependent Claims (13, 14, 15, 16, 20)
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17. A method for producing bisphenol-A from a product solution comprising the following steps:
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forming a product solution comprised of phenol, bisphenol-A, isomers of bisphenol-A, un-reacted reactants and a solvent comprised of two or more solvent components;
selectively controlling the amount of said solvent in the product solution to manipulate the phase behavior of the product solution such that substantially pure crystalline bisphenol-A/phenol adduct can be crystallized from said product solution, where the total weight percent of solvent prior to crystallization is at or below about 18%;
separating substantially pure adduct form the product solution by direct crystallization;
adding solvent comprised of two or more solvent components to the adduct to form an adduct solution, where the total weight percent of solvent prior to crystallization is at or below about 22%;
selectively controlling the amount of said solvent in the adduct solution to manipulate the phase behavior of the adduct solution such that substantially pure bisphenol-A can be crystallized from said adduct solution, separating substantially pure bisphenol-A from the adduct solution by direct crystallization. - View Dependent Claims (21)
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Specification