Production of low-particulate bisphenol and use thereof in the manufacturing of polycarbonate
First Claim
1. A method of producing a low-particulate dihydric aromatic compound, comprising the steps of:
- (a) introducing into a desorber column possessing a non-aggregate packing material an adduct of a dihydric aromatic compound and phenol;
(b) providing an operating temperature range in the desorber column that is sufficiently high and an operating pressure in the column that is sufficiently low such that the adduct is distilled;
(c) discharging from the desorber column a first stream containing substantially all of the phenol; and
(d) discharging from the desorber column a second stream containing substantially all of the dihydric aromatic compound;
whereby the second stream is substantially free of particulate matter added in the desorber column.
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Accused Products
Abstract
Low-particulate dihydric aromatic compounds such as bisphenol-A that can be used in the synthesis of low-particulate polycarbonates are prepared by introducing into a desorber column containing a non-aggregate packing material an adduct of bisphenol and phenol and optionally a stripping gas. The column is maintained at an operating temperature that is sufficiently high and an operating pressure that is sufficiently low such that the adduct is distilled. The stream of phenol and the stripping gas is recovered from the top of the column. A second stream containing bisphenol that is substantially free of added particulate matter is recovered from the bottom of the column. This purified stream of bisphenol-A can further be used in a method of producing optical-grade polycarbonate.
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Citations
39 Claims
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1. A method of producing a low-particulate dihydric aromatic compound, comprising the steps of:
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(a) introducing into a desorber column possessing a non-aggregate packing material an adduct of a dihydric aromatic compound and phenol;
(b) providing an operating temperature range in the desorber column that is sufficiently high and an operating pressure in the column that is sufficiently low such that the adduct is distilled;
(c) discharging from the desorber column a first stream containing substantially all of the phenol; and
(d) discharging from the desorber column a second stream containing substantially all of the dihydric aromatic compound;
whereby the second stream is substantially free of particulate matter added in the desorber column.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of manufacturing low-particulate polycarbonate, comprising the steps of:
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(a) preparing a dihydric aromatic compound by a method comprising the steps of;
(i) introducing into a desorber column possessing a non-aggregate packing material an adduct of a dihydric aromatic compound and phenol;
(ii) providing an operating temperature range in the desorber column that is sufficiently high and an operating pressure in the column that is sufficiently low such that the adduct is distilled;
(iii) discharging from the desorber column a first stream containing substantially all of the phenol; and
(iv) discharging from the desorber column a second stream containing substantially all of the dihydric aromatic compound;
whereby the second stream is substantially free of particulate matter added in the desorber column; and
(b) reacting the dihydric aromatic compound from the second stream with a derivative of carbonic acid to form a polycarbonate to form a low-particulate polycarbonate. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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- 28. A facility for separation of an adduct of a dihydric phenol and phenol into separate streams of dihydric phenol and phenol, comprising a source of the adduct and a desorber column connected to the source of adduct, said desorber column being packed with a non-aggregate packing material.
Specification