Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2002-10-31
2003-11-11
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S198000, C568S727000, C568S728000, C568S806000
Reexamination Certificate
active
06646097
ABSTRACT:
BACKGROUND
This disclosure generally relates to a method for purifying a 1,1-bis(4′-hydroxy-3′-methylphenyl) cyclohexane monomer, and polycarbonates produced utilizing the purified monomer.
The compound, 1,1-bis(4′-hydroxy-3′-methylphenyl) cyclohexane (hereinafter referred to as DMBPC), can be used as a monomer for preparing polycarbonates used in making optical data storage products. DMBPC is generally prepared by reacting cyclohexanone with o-cresol in the presence of a condensation catalyst. During this reaction, side products are created which, if not removed, can result in DMBPC having an unacceptable purity for use as a monomer or as a comonomer for producing polycarbonates. The undesirable side products or impurities include both inorganic and organic species. For example, the impurities can hinder polymerization resulting in low molecular weight polycarbonates that exhibit undesirable physical properties, such as increased brittleness. Furthermore, the impurities in the DMBPC monomer can undesirably produce discoloration in the polycarbonates, thereby affecting the transparency of the product.
BRIEF SUMMARY
Disclosed herein is a method for purifying 1,1-bis(4′-hydroxy-3′-methylphenyl) cyclohexane. The method comprises dissolving said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane in a first solvent consisting essentially of an alcohol to form a first solution; filtering said first solution; adding a second solvent consisting essentially of water to the filtered first solution to form a second solution, wherein said second solution comprises about 40 parts to about 95 parts of the first solvent per 100 parts of the combined weight of the first and second solvents; crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said second solution to form a first crystalline product; dissolving said first crystalline product in a third solvent to form a third solution, wherein the third solvent comprises an aromatic compound; and crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said third solution to produce a second crystalline product.
In another embodiment, a method of producing a polycarbonate comprises-melt reacting a reaction mixture to produce a polycarbonate product, the reaction mixture comprising: a catalyst, a carbonic acid diester of the formula (ZO)
2
C═O, wherein each Z is independently an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical; a second crystalline product of 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane formed by dissolving said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane in a first solvent consisting essentially of an alcohol to form a first solution; filtering said first solution, and adding to the filtered first solution a second solvent consisting essentially of water to form a second solution until said second solution contains from about 40 parts to about 95 parts of said alcohol per 100 parts of the combined weight of said alcohol and water; crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said second solution to produce a first crystalline product; dissolving said first crystalline product in a third solvent comprising a compound having the formula R
1
R
2
(C
6
H
3
)R
3
to form a third solution; and crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said third solution to produce a second crystalline product; and at least one aromatic dihydroxy compound comonomer having the formula:
HO—A
2
—OH,
wherein A
2
is selected from the group consisting of divalent substituted and unsubstituted aromatic radicals.
In another embodiment, a method of producing a polycarbonate comprises interfacially reacting a reaction mixture at a temperature from about 5° C. to about 50° C., and an initial pH from about 9.5 to about 11.0 to produce a polycarbonate product, the reaction mixture comprising: phosgene, a substituted or an unsubstituted monohydric phenol having the formula R
5
(C
6
H
4
)OH, wherein R
5
comprises hydrogen and C
1
-C
12
linear and branched alkyland cycloalkyl groups; a tertiary amine having the formula R
6
R
7
R
8
N, wherein R
6
, R
7
, and R
8
selected from C
1
-C
12
linear and branched alkyl radicals; at least one halogen-containing hydrocarbon solvent; water, an alkali metal hydroxide selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide; a second crystalline product of 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane formed by dissolving said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane in a first solvent consisting essentially of an alcohol to form a first solution; filtering said first solution, and adding to the filtered first solution a second solvent consisting essentially of water to form a second solution until said second solution contains from about 40 parts to about 95 parts of said alcohol per 100 parts of the combined weight of said alcohol and water; crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said second solution to produce a first crystalline product; dissolving said first crystalline product in a third solvent comprising a compound having the formula R
1
R
2
(C
6
H
3
)R
3
to form a third solution; and crystallizing said 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane from said third solution to produce a second crystalline product.; and at least one aromatic dihydroxy compound comonomer having the formula:
HO—A
2
—OH,
wherein A
2
is selected from the group consisting of divalent substituted and unsubstituted aromatic radicals; wherein the phosgene is used in an amount from about stoichiometric to about 50 mole percent excess relative to the total moles of the second crystalline product and the at least one aromatic dihydroxy compound comonomer.
The above described and other features are exemplified by the following detailed description.
DETAILED DESCRIPTION
A process for purifying 1,1-bis(4′-hydroxy-3′-methylphenyl)cyclohexane (hereinafter referred to as “DMBPC”) generally includes purifying a crude DMBPC compound produced from a condensation reaction between cyclohexanone and o-cresol. As used herein, the term “crude DMBPC” is defined as the DMBPC monomer obtained directly from the condensation reaction.
The crude DMBPC is first dissolved in a solvent consisting essentially of an alcohol to form a first solution. Alcohols that are miscible with water are appropriate first solvents for dissolving the crude DMBPC. Preferred alcohols are represented by the formula R
4
OH, wherein R
4
comprises a linear or branched C
1
-C
4
alkyl radical. Examples of suitable alcohols that can be used include, but are not limited to, methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, and tert-butanol. In a specific embodiment, the alcohol is methanol. For a given first solvent, the amount of DMBPC that can be dissolved is dependent on the temperature at which the dissolution is conducted. Generally, the higher the temperature, the greater the solubility and concentration of DMBPC in the first solvent. The temperature at which the first solution is prepared can vary from about an ambient temperature to about a reflux temperature of the first solvent.
The first solution thus obtained is then filtered to remove any insoluble material. Filtration can be performed by any of the techniques generally known to those skilled in the art. A second solvent consisting essentially of water is then added to the filtered first solution to form a second solution. The amount of water to be added can vary such that the proportion of alcohol and water in the second solution are at a ratio of about 40:60 to a ratio of about 5:95 by volume, respectively. In one embodiment, the concentration of DMBPC in the second solution should be such that the crystals formed from a suibsequent cooling process do not entrain significant level
Davis Gary C.
Kapila Debjani
Krishnamurti Ramesh
Radhakrishna A. S.
Shyadligeri Ashok
Boykin Terressa M.
General Electric Company
LandOfFree
Method for purifying... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for purifying..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for purifying... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3126794