U.S. patent application number 11/848009 was filed with the patent office on 2008-02-07 for methods for producing and purifying 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers and polycarbonates derived therefrom.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Gautam Chatterjee, Anantharaman Dhanabalan, Vinod Kumar Rai, Suresh Shanmugam, Veeraraghavan Srinivasan.
Application Number | 20080033123 11/848009 |
Document ID | / |
Family ID | 35055265 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080033123 |
Kind Code |
A1 |
Srinivasan; Veeraraghavan ;
et al. |
February 7, 2008 |
METHODS FOR PRODUCING AND PURIFYING
2-HYDROCARBYL-3,3-BIS(4-HYDROXYARYL)PHTHALIMIDINE MONOMERS AND
POLYCARBONATES DERIVED THEREFROM
Abstract
Disclosed herein is a method for producing a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The method
comprises forming a reaction mixture comprising at least one
substituted or unsubstituted phenolphthalein, at least one
substituted or unsubstituted primary hydrocarbyl amine, and an acid
catalyst; and heating the reaction mixture to a temperature of less
than 180.degree. C. to remove a distillate comprising water and
form a crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
product; where the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:
##STR1## where R.sup.1 is selected from the group consisting of a
hydrogen and a hydrocarbyl group, and R.sup.2 is selected from the
group consisting of a hydrogen, a hydrocarbyl group, and a
halogen.
Inventors: |
Srinivasan; Veeraraghavan;
(Bangalore, IN) ; Shanmugam; Suresh; (Bangalore,
IN) ; Chatterjee; Gautam; (Bangalore, IN) ;
Dhanabalan; Anantharaman; (Bangalore, IN) ; Rai;
Vinod Kumar; (Bangalore, IN) |
Correspondence
Address: |
SABIC - LEXAN;SABIC Innovative Plastics - IP Legal
ONE PLASTICS AVE.
PITTSFIELD
MA
01201-3697
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
1 River Road
Schenectady
NY
12345
|
Family ID: |
35055265 |
Appl. No.: |
11/848009 |
Filed: |
August 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10815880 |
Mar 31, 2004 |
7277230 |
|
|
11848009 |
Aug 30, 2007 |
|
|
|
Current U.S.
Class: |
526/64 ; 528/210;
548/472 |
Current CPC
Class: |
C07D 209/34 20130101;
C08G 64/12 20130101 |
Class at
Publication: |
526/064 ;
528/210; 548/472 |
International
Class: |
C08G 64/04 20060101
C08G064/04; C07D 209/44 20060101 C07D209/44; C08F 6/00 20060101
C08F006/00 |
Claims
1. A method for producing a
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine, comprising: forming a
reaction mixture comprising at least one substituted or
unsubstituted phenolphthalein, at least one substituted or
unsubstituted primary aryl amine, and an acid catalyst; and heating
the reaction mixture to a temperature of less than 180.degree. C.,
removing a distillate comprising water and isolating a product
comprising 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine having the
formula: ##STR30## wherein R.sup.1 is an aryl group and R.sup.2 is
selected from the group consisting of a hydrogen, a hydrocarbyl
group, and a halogen.
2. The method of claim 1, wherein the product purity is at least
99.9 area percent 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine by
HPLC analysis.
3. The method of claim 1, wherein the acid catalyst is selected
from a group consisting of a substituted or an unsubstituted
aliphatic amine hydrochloride, an aromatic amine hydrochloride, or
mixtures of the foregoing amine hydrochlorides.
4. The method of claim 1, wherein the reaction mixture comprises
phenolphthalein and aniline.
5. The method of claim 1, wherein the
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine is
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
6. The method of claim 1, further comprising: combining the
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine product with an aqueous
base to provide a first solution; treating the first solution with
a solid adsorbent and then filtering the first solution to provide
a second solution, treating the second solution with an aqueous
acid to form a precipitate and; isolating the precipitate
comprising 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.
7. The method of claim 6, wherein the aqueous base comprises an
alkali metal or alkaline earth metal hydroxide, carbonate, or
bicarbonate.
8. The method of claim 6, wherein the solid adsorbent comprises an
activated carbon.
9. The method of claim 6, wherein the
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine is
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine
10. The method of claim 1, further comprising contacting the
product comprising 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine with
an aliphatic alcohol and isolating a purified
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.
11. The method of claim 10, wherein the purified
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than or
equal to 1,000 parts per million of a substituted or an
unsubstituted phenolphthalein relative to an overall weight of
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.
12. The method of claim 10, wherein the aliphatic alcohol is
methanol, ethanol, iso-propanol, iso-butanol, n-butanol, tertiary
butanol, n-pentanol, iso-pentanol, cyclohexanol, ethylene glycol,
propylene glycol, neopentyl glycol or mixtures of the foregoing
aliphatic alcohols.
13. The method of claim 10, wherein the
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine is
2-phenyl-3,3-(bis-4-hydroxyphenyl)phthalimidine
14. A method for purifying
2-phenyl-3,3-bis(4-hydroxphenyl)phthalimidine, comprising:
combining a mixture comprising
2-phenyl-3,3-bis(4-hydroxphenyl)phthalimidine mixture with an
aqueous base to provide a first solution; treating the first
solution with an activated carbon and filtering to provide a second
solution; treating the second solution with an aqueous acid to form
a precipitate; and isolating the precipitate comprising the
2-phenyl-3,3-bis(4-hydroxphenyl)phthalimidine mixture.
15. The method of claim 14, wherein the
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine mixture comprises
less than or equal to about 1000 parts per million of
phenolphthalein relative to an overall weight of
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
16. A polycarbonate composition comprising structural units derived
from the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine produced by the
method of claim 1.
17. A polycarbonate composition comprising structural units derived
from the 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine produced by the
method of claim 6.
18. A polycarbonate composition comprising structural units derived
from the 2-aryl-3,3-bis(4-hydroxyphenyl)phthalimidine produced by
the method of claim 10.
19. An article comprising the polymer composition of claim 16.
20. An article comprising the composition of claim 17.
21. An article comprising the composition of claim 18.
22. A method for producing
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine, comprising: a) forming
a reaction mixture comprising at least one substituted or
unsubstituted phenolphthalein, at least one substituted or
unsubstituted primary aryl amine, and an acid catalyst; heating the
reaction mixture to a temperature of less than 180.degree. C.,
removing a distillate comprising water and isolating a product
mixture comprising 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine
having the formula: ##STR31## wherein R.sup.1 is an aryl group and
R.sup.2 is selected from the group consisting of a hydrogen, a
hydrocarbyl group, and a halogen; b) combining the product mixture
from step a) with an aqueous base to provide a first solution,
treating the first solution with a carbon adsorbent and filtering
to provide a second solution, treating the second solution with an
aqueous acid to form a precipitate, and isolating the precipitate;
c) contacting the precipitate from step b) with an aliphatic
alcohol to produce a purified
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine and isolating the
purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the
purified 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to 1,000 parts per million of a substituted or an
unsubstituted phenolphthalein relative to the overall weight of
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine.
23. The method of claim 22, wherein the
2-aryl-3,3-bis(4-hydroxyaryl)phthalimidine is
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
24. A polycarbonate composition comprising structural units derived
from the 2-aryl-3,3,-bis(hydroxyphenyl)phthalimidine produced by
the method of claim 22.
25. An article comprising the polycarbonate composition of claim
24.
26. The polycarbonate of claim 16, wherein the polycarbonate is
prepared by melt transesterification polymerization.
27. The polycarbonate of claim 16, wherein the polycarbonate is
prepared by interfacial polymerization.
28. The polycarbonate of claim 27, wherein the interfacial
polymerization is a bischloroformate polymerization method.
29. The polycarbonate of claim 27, wherein the interfacial
polymerization comprises a tubular reactor.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Divisional of U.S. patent application
Ser. No. 10/815,880, filed Mar. 31, 2004, which is fully
incorporated herein by reference.
BACKGROUND
[0002] The present disclosure generally relates to a method for
producing and purifying
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers, and
polycarbonates as well as other polymers derived utilizing the
monomers.
[0003] Phenolphthalein has been used as an aromatic dihydroxy
compound monomer for preparing polycarbonates, which are generally
characterized with excellent ductility and high glass transition
temperatures. Certain derivatives of phenolphthalein have also been
used as aromatic dihydroxy compound monomers to prepare
polycarbonate resins as well as polyarylate resins. For example,
polycarbonate homopolymers have been prepared by an interfacial
polycondensation method using phosgene and monomers such as
3,3-bis(4-hydroxyphenyl)phthalimidine and
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (hereinafter
sometimes referred to as "para,para-PPPBP").
[0004] Lin and Pearce (Journal of Polymer Science: Polymer
Chemistry Edition, (1981) Vol. 19, pp. 2659-2670) reported the
synthesis of para, para-PPPBP for preparing polycarbonates and
other polymers by refluxing phenolphthalein and aniline
hydrochloride in aniline for 6 hours, followed by recrystallization
from ethanol. During this reaction, side products are created
which, if not removed, can result in para, para-PPPBP having an
unacceptable purity for use as a monomer or as a comonomer. The
undesirable side products or impurities generally include both
inorganic and organic species. With regard to the manufacture of
polycarbonate, the impurities can hinder polymerization and result
in low weight average molecular weight polycarbonates, example,
less than about 22,000 Daltons for melt polymerization and less
than about 50,000 Daltons for an interfacial polymerization that
exhibit undesirable physical properties, such as increased
brittleness, that is, poor ductility properties. Furthermore, the
impurities in the para, para-PPPBP monomer include, for example,
trace (parts per million) levels of phenolphthalein or
phenolphthalein residues that can undesirably produce discoloration
in the polycarbonates and other polymers derived therefrom, thereby
affecting the transparency of the polymer product. Coloration is
not desirable for many commercial applications. U.S. Pat. No.
5,344,910 discloses that copolymers of para, para-PPPBP were found
to have poor melt stability resulting in foamy polymer melts and
moldings, and discoloration of the resin during melt
processing.
[0005] It would therefore be desirable to develop a process for
preparing relatively pure phenolphthalein derivatives such as
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which can then
be used for producing polycarbonates and other polymers having
improved properties, such as lower color, e.g., a low yellowness
index (YI) of less than about 10, and higher weight average
molecular weight.
BRIEF SUMMARY
[0006] Briefly, in one aspect, a method for producing a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises forming
a reaction mixture comprising at least one substituted or
unsubstituted phenolphthalein, at least one substituted or
unsubstituted primary hydrocarbyl amine, and an acid catalyst; and
heating the reaction mixture to a temperature of less than
180.degree. C. to remove a distillate comprising water and form a
crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product;
where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a
formula: ##STR2## where R.sup.1 is selected from the group
consisting of a hydrogen and a hydrocarbyl group, and R.sup.2 is
selected from the group consisting of a hydrogen, a hydrocarbyl
group, and a halogen.
[0007] In a second aspect, a method for purifying a crude
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises
dissolving the crude
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product in an
aqueous base to provide a first solution; treating the first
solution with an activated carbon and filtering to provide a second
solution; and treating the second solution with an aqueous acid to
precipitate a purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of formula:
##STR3## where R.sup.1 is selected from the group consisting of a
hydrogen and a hydrocarbyl group, and R.sup.2 is selected from the
group consisting of a hydrogen, a hydrocarbyl group, and a halogen,
and further where said purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of the purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
[0008] In a third aspect, a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)} phthalimidine has
a formula of: ##STR4## where R.sup.1 is selected from the group
consisting of a hydrogen and a hydrocarbyl group, and R.sup.2 is
selected from the group consisting of a hydrogen, a hydrocarbyl
group, and a halogen.
[0009] In a fourth aspect, a
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprises less than
or equal to 1,000 parts per million of
2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine,
relative to an overall weight of the
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
[0010] In a fifth aspect, a method for producing a
homopolycarbonate or a copolycarbonate comprising structural units
derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine,
where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
comprises less than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
impurity relative to an overall weight of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; is selected from
the group consisting of a melt transesterification polymerization
method and an interfacial polymerization method.
[0011] In a sixth aspect, a melt transesterification polymerization
method comprises: combining a catalyst and a reactant composition
to form a reaction mixture, where the reactant composition
comprises a carbonic acid diester, a
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, and at least one
aromatic dihydroxy compound comonomer, where the carbonic acid
diester is of the formula (ZO).sub.2C.dbd.O, wherein each Z is
independently an unsubstituted or substituted alkyl radical, or an
unsubstituted or substituted aryl radical, and, wherein the
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprises less than
or equal to 1,000 parts per million of
2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine
relative to an overall weight of the
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine; and mixing the
reaction mixture under reactive conditions for a time period to
produce a polycarbonate product.
[0012] In a seventh aspect, a polycarbonate comprises structural
units derived from a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine: ##STR5## where
R.sup.1 is selected from the group consisting of a hydrogen and a
hydrocarbyl group, and R.sup.2 is selected from the group
consisting of a hydrogen, a hydrocarbyl group, and a halogen, and
further wherein the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
[0013] In an eighth aspect, a lens comprises a polycarbonate, where
the polycarbonate comprises: structural units of formula derived
from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine: ##STR6##
where R.sup.1 is selected from the group consisting of a hydrogen
and a hydrocarbyl group, and R.sup.2 is selected from the group
consisting of a hydrogen, a hydrocarbyl group, and a halogen; and
further where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
comprises less than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)} phthalimidine
relative to an overall weight of said
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; and a yellowness
index of less than 10 as measured on a 3 millimeter thick plaque in
accordance with ASTM D1925.
[0014] In a ninth aspect, a polycarbonate copolymer comprises
structural units of formula derived from a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine: ##STR7## where
R.sup.1 is selected from the group consisting of a hydrogen and a
hydrocarbyl group, and R.sup.2 is selected from the group
consisting of a hydrogen, a hydrocarbyl group, and a halogen; and
further where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
comprises less than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of said
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; where said
polycarbonate copolymer has a yellowness index of less than 10 as
measured on a 3 millimeter thick plaque in accordance with ASTM
D1925.
[0015] In a tenth aspect, a polycarbonate copolymer comprises
structural units of formula derived from a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine: ##STR8## where
R.sup.1 is selected from the group consisting of a hydrogen and a
hydrocarbyl group, and R.sup.2 is selected from the group
consisting of a hydrogen, a hydrocarbyl group, and a halogen; where
the polycarbonate copolymer has a yellowness index of less than 10
as measured on a 3 millimeter thick plaque in accordance with ASTM
D1925.
[0016] The above described and other features are exemplified by
the following detailed description.
DETAILED DESCRIPTION
[0017] For the purposes of this disclosure, the term "hydrocarbyl"
is defined herein as a monovalent moiety formed by removing a
hydrogen atom from a hydrocarbon. Representative hydrocarbyls are
alkyl groups having 1 to 25 carbon atoms, such as methyl, ethyl,
propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, undecyl, decyl,
dodecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl,
tricosyl, and the isomeric forms thereof, aryl groups having 6 to
25 carbon atoms, such as ring-substituted and ring-unsubstituted
forms of phenyl, tolyl, xylyl, naphthyl, biphenyl, tetraphenyl, and
the like; aralkyl groups having 7 to 25 carbon atoms, such as
ring-substituted and ring-unsubstituted forms of benzyl, phenethyl,
phenpropyl, phenbutyl, naphthoctyl, and the like; and cycloalkyl
groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,
cycloheptyl, cyclooctyl, and the like. The term "aryl" as used
herein refers to various forms of aryl groups that have been
described hereinabove for the "hydrocarbyl" group.
[0018] The present disclosure is generally directed to producing
and purifying phenolphthalein derivatives, which are suitable for
use as monomers for preparing polymers. An exemplary
phenolphthalein derivative,
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines is of formula
(I): ##STR9## wherein R.sup.1 is selected from a group consisting
of a hydrogen and a hydrocarbyl group, and R.sup.2 is selected from
the group consisting of a hydrogen, a hydrocarbyl group, and a
halogen. For example, a 2-aryl-3,3-bis(4-hydroxyaryl)phthalimidines
can be prepared by the reaction of a hydrocarbyl amine, such as,
for example, an aromatic amine (also referred to herein as "aryl
amine"), e.g., an aniline, of formula (II): ##STR10## wherein
R.sup.1 is as defined above; with a phenolphthalein of formula
(III): ##STR11## wherein R.sup.2 is as previously defined. An acid
catalyst is generally used to facilitate formation of the
phthalimidine product. Suitable acid catalysts that can be used
include amine salts of mineral acids. Examples of suitable mineral
acids include hydrochloric acid, sulfuric acid, and nitric acid.
Examples of suitable amines include primary, secondary, and
tertiary amines having any combination of aliphatic and aromatic
groups bonded to the amine nitrogen. Suitable examples of amine
salt catalysts include primary, secondary, and tertiary amine
hydrochlorides. Hydrochloride salts of the primary aromatic amines
of formula (II) are preferred since the amines of formula (II) also
serve as the starting material for preparing the phthalimidines of
formula (I). In one embodiment, the catalyst is introduced as a
pre-formed salt into the reactor. In another embodiment, the
catalyst is generated in the reactor by first charging the amine of
formula (II) into the reactor, and then adding about 1/3 to about 1
part by weight of an appropriate mineral acid to phenolphthalein.
In still another embodiment, about 0.1 parts to about 0.3 parts by
weight of hydrogen chloride gas is introduced into a reactor
charged with the aryl amine to form an appropriate amount of the
aryl amine hydrochloride catalyst. More hydrochloric acid or more
hydrogen chloride gas can also used, but is generally not required.
A solvent can optionally be employed to form the aryl amine
hydrochloride. The solvent can then be removed (if necessary), and
the aryl amine of formula (II) can be added, followed by addition
of phenolphthalein (III). The reaction of phenolphthalein (III)
with the aryl amine (II) proceeds by a condensation reaction to
form the desired phthalimidine product (I). An excess of the aryl
amine over the phenolphthalein may be used to keep the reaction
proceeding in the forward direction. Likewise, a higher reaction
temperature with or without removal of water by-product also
facilitates product formation. However, in order to enhance the
selectivity of 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
(I), and suppress the formation of undesired
(2-hydroxyaryl)(4-hydroxyaryl)phthalimidine by-product, for
example, it is preferred to control the temperature of the reaction
mixture, and the rate of removal of water as well. The temperature
of the reaction mixture and rate of water removal is controlled
such that the crude PPPBP product is at least 97.5 area percent
pure 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in one
embodiment, and at least 98 area percent pure in another
embodiment. The chemical structure of
(2-hydroxyaryl)(4-hydroxyaryl)phthalimidine by-product is shown in
formula (IV) below. ##STR12## wherein R.sup.1 and R.sup.2 are as
previously described.
[0019] In one embodiment, the reaction temperature is controlled
such that the water by-product (calculated based on the moles of
the phenolphthalein (III) which is preferably the limiting reagent)
distills over a period of about 12 hours to about 20 hours. If the
reaction mixture is heated such that the amount of water by-product
distills within about 6 hours, the phthalimidine product of formula
(I) has a relatively greater amount of the
(2-hydroxyaryl)(4-hydroxyaryl)phthalimidine impurity shown in
formula (IV). Therefore, although a higher reaction temperature
ensures a quicker consumption of the phenolphthalein (III), it also
leads to formation of a higher amount of the impurity of formula
(IV). If the reaction temperature is not sufficiently high, and
water by-product is not removed, a relatively large amount of the
phenolphthalein remains unreacted, thereby leading to an inferior
product, e.g., forms colored byproducts during melt mixing, forms
low molecular weight polymers, and the like. Thus, in one
embodiment, the reaction mixture is heated to a temperature of
about 150.degree. C. to about 175.degree. C. to remove water
by-product and form the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product. In
another embodiment, the reaction mixture is heated to a temperature
of about 150.degree. C. to about 170.degree. C.
[0020] By way of example, phenolphthalein (R.sup.2 is H, R.sup.3 is
phenyl in formula (III)) was reacted with aniline (R.sup.3 is H in
formula (II)) in the presence of aniline hydrochloride as the
catalyst to form 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine
(i.e., para,para-PPPBP), as shown in formula (V). ##STR13##
[0021] As will be discussed in the Example Section, the so-formed
para, para-PPPBP was produced at high yields and was used to
produce polycarbonates with a YI of less than about 10 and high
weight average molecular weights. Moreover, the reaction did not
produce any detectable (and undesirable) isomers of para,
para-PPPBP such as the ortho, para-PPPBP isomer shown in Formula
(VI) below. ##STR14##
[0022] Isolation of the desired phenolphthalein derivative from the
reaction mixture includes quenching the mixture with an aqueous
mineral acid, such as aqueous hydrochloric acid, and precipitating
the crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The
crude product is then dissolved in an aqueous inorganic base
comprising an alkali metal or alkaline earth metal hydroxide,
carbonate, or bicarbonate to provide a first solution. Aqueous
sodium hydroxide is preferably used. Next, the first solution of
the crude product is treated with a suitable solid adsorbent that
can remove color-forming species present in the solution. In an
embodiment, commercially available activated carbon can be used.
Treatment with the activated carbon removes color-forming species
present in the solution. Suitable activated carbon include, but are
not intended to be limited to, the NORIT series of activated carbon
available from Norit Corporation, and those activated carbons
commercially available from E. Merck Company. The decolorizing
efficiency of the activated carbon is indicated by its methylene
blue number. Generally, an activated carbon with a relatively
higher methylene blue number is less expensive than an activated
carbon having a relatively lower methylene blue number. Applicants
find that even activated carbons having relatively higher methylene
blue numbers are effective decolorizing agents. After treatment
with the activated carbon, the resulting mixture is filtered to
provide a second solution.
[0023] In addition to functioning as a decolorizing agent, the
activated carbon treatment also aids in selectively adsorbing the
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
isomeric impurity. Thus, one method for purifying a crude
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product comprises
contacting an aqueous base solution of the crude product with the
activated carbon and filtering off the carbon to provide a second
solution. The second solution may again be treated in the same
manner, if desired, to provide further reductions in the levels of
the 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
impurity. In an embodiment, the step of treating and filtering the
first solution is done such that it is effective to reduce an
amount of
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine to
less than or equal to 1,000 parts per million relative to an
overall weight of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
[0024] The decolorized and purified solution is next treated with
an aqueous mineral acid, such as aqueous hydrochloric acid to
precipitate 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The
precipitate is then finally stirred with an aliphatic alcohol to
remove any trace of the phenolphthalein that may still be present
and subsequently filtered to furnish purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. Suitable
aliphatic alcohols include any aliphatic monohydric or dihydric
alcohol. Non-limiting examples of suitable aliphatic alcohols
include methanol, ethanol, iso-propanol, iso-butanol, n-butanol,
tertiary butanol, n-pentanol, iso-pentanol, cyclohexanol, ethylene
glycol, propylene glycol, neopentyl glycol and the like. In a
particular embodiment, aliphatic monohydric alcohols that are
miscible with water, such as methanol, ethanol, and isopropanol are
used. Methanol is the preferred aliphatic alcohol for removing
phenolphthalein. The so-produced and purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine preferably
comprises less than or equal to 1,000 parts per million of the
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
isomeric impurity. Further, the purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine preferably
comprises less than or equal to 1,000 parts per million of the
phenolphthalein starting material.
[0025] In another embodiment, a method for purifying crude
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product comprises
dissolving the crude product in an aqueous base solution, treating
the aqueous base solution of the crude product with the activated
carbon, filtering off the carbon to provide a second solution, and
acidifying the second solution with an aqueous acid to precipitate
the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which has a
relatively low level of the
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
impurity, e.g., less than 1,000 parts per million. The resulting
product can then be contacted with an aliphatic alcohol in the
manner previously described.
[0026] The general methods described hereinabove can advantageously
be applied for preparing para, para-PPPBP having an undetectable
level of ortho, para-PPPBP (as measured by HPLC technique). In one
embodiment, the purified para,para-PPPBP may also comprise up to
1,000 parts per million of phenolphthalein.
[0027] The 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines,
including the exemplary
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, are commercially
valuable monomers or comonomers for producing a variety of polymers
and polymer compositions formed by reactions of the phenolic OH
groups of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines.
Suitable polymers that can be produced are polymers selected from
the group consisting of homopolymers and copolymers of a
polycarbonate, a polyestercarbonate, a polyester, a polyesteramide,
a polyimide, a polyetherimide, a polyamideimide, a polyether, a
polyethersulfone, a polycarbonate--polyorganosiloxane block
copolymer, a copolymer comprising aromatic ester, estercarbonate,
and carbonate repeat units; and a polyetherketone. A suitable
example of a copolymer comprising aromatic ester, estercarbonate,
and carbonate repeat units is the copolymer produced by the
reaction of a hydroxy-terminated polyester, such as the product of
reaction of isophthaloyl chloride, and terephthaloyl chloride with
resorcinol, with phosgene and an aromatic dihydroxy compound, such
as bisphenol A.
[0028] In one embodiment, polycarbonates having desirable
properties are synthesized, wherein the polycarbonates include
structural units of formula (VII): ##STR15## which are derived from
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; wherein R.sup.1
and R.sup.2 are as described previously; and the C.dbd.O structural
units are derived from a C.dbd.O donor such as phosgene or a
carbonic acid diester; where the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of said
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
[0029] The polycarbonate composition may further comprise
structural units derived from at least one other aromatic dihydroxy
compound such as is represented by the general formula (VIII):
##STR16## wherein each G.sup.1 is an independently aromatic group;
E is selected from the group consisting of an alkylene group, an
alkylidene group, a cycloaliphatic group, a sulfur-containing
linkage group, a phosphorus-containing linkage group, an ether
linkage group, a carbonyl group, a tertiary nitrogen group, and a
silicon-containing linkage group; R.sup.3 is a hydrogen or a
monovalent hydrocarbon group each; Y.sup.1 is independently
selected from the groups consisting of a monovalent hydrocarbyl
group, an alkenyl group, an allyl group, a halogen, an oxy group
and a nitro group; each m is independently a whole number from zero
through the number of positions on each respective G.sup.1
available for substitution; p is a whole number from zero through
the number of positions on E available for substitution; t is a
natural number greater than or equal to one; s is either zero or
one; and u is a whole number.
[0030] Suitable examples of E include cyclopentylidene,
cyclohexylidene, 3,3,5-trimethylcyclohexylidene,
methylcyclohexylidene, 2-[2.2.1]-bicycloheptylidene,
neopentylidene, cyclopentadecylidene, cyclododecylidene, and
adamantylidene; a sulfur-containing linkage such as sulfide,
sulfoxide or sulfone, a phosphorus-containing linkage such as
phosphinyl, phosphonyl, an ether linkage, a carbonyl group, a
tertiary nitrogen group, and a silicon-containing linkage such as a
silane or siloxy linkage.
[0031] In the aromatic dihydroxy comonomer compound shown in
Formula (VIII), when more than one Y.sup.1 substituent is present,
they may be the same or different. The same holds true for the
R.sup.3 substituent. Where "s" is zero in formula (VIII) and "u" is
not zero, the aromatic rings are directly joined with no
intervening alkylidene or other bridge. The positions of the
hydroxyl groups and Y.sup.1 on the aromatic nuclear residues
G.sup.1 can be varied in the ortho, meta, or para positions and the
groupings can be in vicinal, asymmetrical or symmetrical
relationship, where two or more ring carbon atoms of the
hydrocarbon residue are substituted with Y.sup.1 and hydroxyl
groups. In some embodiments, the parameters "t", "s", and "u" are
each one; both G.sup.1 radicals are unsubstituted phenylene
radicals; and E is an alkylidene group such as isopropylidene. In
particular embodiments, both G.sup.1 radicals are p-phenylene,
although both may be ortho- or meta-phenylene or one ortho- or
meta-phenylene and the other para-phenylene.
[0032] Some illustrative, non-limiting examples of aromatic
dihydroxy compounds of formula (VIII) include the
dihydroxy-substituted aromatic hydrocarbons disclosed by name or
formula (generic or specific) in U.S. Pat. No. 4,217,438. Some
particular examples of aromatic dihydroxy compound comonomers
include, but are not intended to be limited to,
2,4'-dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane,
bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane,
bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane,
1,1-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxy-2-chlorophenyl)ethane,
2,2-bis(4-hydroxyphenyl)propane (bisphenol A);
2,2-bis(3-chloro-4-hydroxyphenyl)propane;
2,2-bis(3-bromo-4-hydroxyphenyl)propane;
2,2-bis(4-hydroxy-3-methylphenyl)propane;
2,2-bis(4-hydroxy-3-isopropylphenyl)propane;
2,2-bis(3-t-butyl-4-hydroxyphenyl)propane;
2,2-bis(3-phenyl-4-hydroxyphenyl)propane;
2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane;
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane;
2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane;
2,2-bis(3-chloro-4-hydroxy-5-methylphenyl)propane;
2,2-bis(3-bromo-4-hydroxy-5-methylphenyl)propane;
2,2-bis(3-chloro-4-hydroxy-5-isopropylphenyl)propane;
2,2-bis(3-bromo-4-hydroxy-5-isopropylphenyl)propane;
2,2-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)propane;
2,2-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)propane;
2,2-bis(3-chloro-5-phenyl-4-hydroxyphenyl)propane;
2,2-bis(3-bromo-5-phenyl-4-hydroxyphenyl)propane;
2,2-bis(3,5-disopropyl-4-hydroxyphenyl)propane;
2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane;
2,2-bis(3,5-diphenyl-4-hydroxyphenyl)propane;
2,2-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)propane;
2,2-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)propane;
2,2-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)propane;
2,2-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)propane;
2,2-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)propane;
2,2-bis(4-hydroxy-3-ethylphenyl)propane,
2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,
2,2-bis(3,5,3',5'-tetrachloro-4,4'-dihydroxyphenyl)propane,
bis(4-hydroxyphenyl)cyclohexylmethane,
2,2-bis(4-hydroxyphenyl)-1-phenylpropane,
1,1-bis(4-hydroxyphenyl)cyclohexane;
1,1-bis(3-chloro-4-hydroxyphenyl)cyclohexane;
1,1-bis(3-bromo-4-hydroxyphenyl)cyclohexane;
1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane;
1,1-bis(4-hydroxy-3-isopropylphenyl)cyclohexane;
1,1-bis(3-t-butyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-dibromo-4-hydroxyphenyl)cyclohexane;
1,1-bis(4'-hydroxy-3'methylphenyl)cyclohexane (DMBPC),
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane;
4,4'-[1-methyl-4-(1-methyl-ethyl)-1,3-cyclohexandiyl]bisphenol (1,3
BHPM),
4-[1-[3-(4-hydroxyphenyl)-4-methylcyclohexyl]-1-methyl-ethyl]-phen-
ol (2,8 BHPM),
3,8-dihydroxy-5a,10b-diphenylcoumarano-2',3',2,3-coumarane (DCBP),
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine,
1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)cyclohexane;
1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)cyclohexane;
1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)cyclohexane;
1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)cyclohexane;
1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)cyclohexane;
1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3-chloro-5-phenyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-disopropyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-diphenyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)cyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)cyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)cyclohexane;
1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-bromo-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(4-hydroxy-3-methylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(4-hydroxy-3-isopropylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-dichloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-dibromo-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
bis(3-chloro-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-disopropyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(3,5-diphenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)-3,3,5-trimethylcyclohexane;
1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohe-
xane;
1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyc-
lohexane; 4,4-bis(4-hydroxyphenyl)heptane,
4,4'dihydroxy-1,1-biphenyl;
4,4'-dihydroxy-3,3'-dimethyl-1,1-biphenyl;
4,4'-dihydroxy-3,3'-dioctyl-1,1-biphenyl;
4,4'-(3,3,5-trimethylcyclohexylidene)diphenol,
4,4'-bis(3,5-dimethyl)diphenol, 4,4'-dihydroxydiphenylether;
4,4'-dihydroxydiphenylthioether;
1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene;
1,3-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene;
1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene,
1,4-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene
2,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxydiphenylsulfone (BPS),
bis(4-hydroxyphenyl)methane, 2,6-dihydroxy naphthalene;
hydroquinone; resorcinol, C1-3 alkyl-substituted resorcinols,
3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol,
1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol, and
2,2,2',2'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobi[1H-indene]-6,6'-d-
iol. The most typical aromatic dihydroxy compound is Bisphenol A
(BPA).
[0033] In some embodiments, an isosorbide comonomer can be used
with the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomer
to produce polycarbonate copolymers. Isosorbide, sometimes also
called 1, 4:3,6-dianhydro-D-glucitol, is a rigid, chemically, and
thermally stable aliphatic diol that tends to produce copolymers
having higher glass transition temperatures, as compared to
comonomer compositions which do not include isosorbide.
[0034] The carbonic acid diester described above has the general
formula (IX): (ZO).sub.2C.dbd.O (IX), wherein each Z is
independently an unsubstituted or substituted alkyl radical, or an
unsubstituted or substituted aryl radical. Suitable examples of
carbonic acid diesters include, but are not intended to be limited
to, ditolyl carbonate, m-cresyl carbonate, dinaphthyl carbonate,
diphenyl carbonate, diethyl carbonate, dimethyl carbonate, dibutyl
carbonate, dicyclohexyl carbonate, and combinations of two or more
carbonic acid diesters thereof. Diphenyl carbonate is widely used
as a carbonic acid diester due to its low cost and ready
availability on a commercial scale. If two or more of the carbonic
acid diesters listed above are utilized, preferably one of the
carbonic acid diesters is diphenyl carbonate.
[0035] Suitable carbonic acid diesters include the group of
"activated aromatic carbonates". As used herein, the term
"activated aromatic carbonate" is defined as a diaryl carbonate
that is more reactive than diphenyl carbonate in a
transesterification reaction. Such activated aromatic carbonates
can also be represented by formula (IX), wherein each Z is an aryl
radical having 6 to 30 carbon atoms. More specifically, the
activated carbonates have the general formula (X): ##STR17##
wherein Q and Q' are each independently an ortho-positioned
activating group; A and A' are each independently aromatic rings
which can be the same or different depending on the number and
location of their substituent groups, and a and a' is zero to a
whole number up to a maximum equivalent to the number of
replaceable hydrogen groups substituted on the aromatic rings A and
A' respectively, provided a+a' is greater than or equal to 1. R and
R' are each independently substituent groups such as alkyl,
substituted alkyl, cycloalkyl, alkoxy, aryl, alkylaryl, cyano,
nitro, or halogen. The term b is zero to a whole number up to a
maximum equivalent to the number of replaceable hydrogen atoms on
the aromatic ring A minus the number a, and the number b' is zero
to a whole number up to a maximum equivalent to the number of
replaceable hydrogen atoms on the aromatic ring A' minus the number
a'. The number, type and location of R or R' on the aromatic ring
is not intended to be limited unless they deactivate the carbonate
and lead to a carbonate that is less reactive than diphenyl
carbonate.
[0036] Non-limiting examples of suitable ortho-positioned
activating groups Q and Q' include (alkoxycarbonyl)aryl groups,
halogens, nitro groups, amide groups, sulfone groups, sulfoxide
groups, or imine groups with structures indicated below: ##STR18##
wherein X is halogen or NO.sub.2; M and M' independently comprises
N-dialkyl, N-alkyl aryl, alkyl, or aryl; and R.sup.4 is alkyl or
aryl.
[0037] Specific non-limiting examples of activated aromatic
carbonates include bis(o-methoxycarbonylphenyl)carbonate,
bis(o-chlorophenyl)carbonate, bis(o-nitrophenyl)carbonate,
bis(o-acetylphenyl)carbonate, bis(o-phenylketonephenyl)carbonate,
bis(o-formylphenyl)carbonate. Unsymmetrical combinations of these
structures, wherein the substitution number and type on A and A'
are different, are also contemplated. A preferred structure for the
activated aromatic carbonate is an ester-substituted diaryl
carbonate having the formula (XI): ##STR19## wherein R.sup.5 is
independently at each occurrence a C.sub.1-C.sub.20 alkyl radical,
C.sub.4-C.sub.20 cycloalkyl radical, or C.sub.4-C.sub.20 aromatic
radical; R.sup.6 is independently at each occurrence a halogen
atom, cyano group, nitro group, C.sub.1-C.sub.20 alkyl radical,
C.sub.4-C.sub.20 cycloalkyl radical, C.sub.4-C.sub.20 aromatic
radical, C.sub.1-C.sub.20 alkoxy radical, C.sub.4-C.sub.20
cycloalkoxy radical, C.sub.4-C.sub.20 aryloxy radical,
C.sub.1-C.sub.20 alkylthio radical, C.sub.4-C.sub.20 cycloalkylthio
radical, C.sub.4-C.sub.20 arylthio radical, C.sub.1-C.sub.20
alkylsulfinyl radical, C.sub.4-C.sub.20 cycloalkylsulfinyl radical,
C.sub.4-C.sub.20 arylsulfinyl radical, C.sub.1-C.sub.20
alkylsulfonyl radical, C.sub.4-C.sub.20 cycloalkylsulfonyl radical,
C.sub.4-C.sub.20 arylsulfonyl radical, C.sub.1-C.sub.20
alkoxycarbonyl radical, C.sub.4-C.sub.20 cycloalkoxycarbonyl
radical, C.sub.4-C.sub.20 aryloxycarbonyl radical, C.sub.2-C.sub.60
alkylamino radical, C.sub.6-C.sub.60 cycloalkylamino radical,
C.sub.5-C.sub.60 arylamino radical, C.sub.1-C.sub.40
alkylaminocarbonyl radical, C.sub.4-C.sub.40
cycloalkylaminocarbonyl radical, C.sub.4-C.sub.40 arylaminocarbonyl
radical, or C.sub.1-C.sub.20 acylamino radical; and c is
independently at each occurrence an integer 0-4. At least one of
the substituents CO.sub.2R.sup.5 is preferably attached in the
ortho position of formula (XI).
[0038] Examples of preferred ester-substituted diaryl carbonates
include, but are not limited to, bis(methylsalicyl)carbonate (CAS
Registry No. 82091-12-1) (also known as BMSC or
bis(o-methoxycarbonylphenyl)carbonate), bis(ethyl
salicyl)carbonate, bis(propyl salicyl) carbonate,
bis(butylsalicyl)carbonate, bis(benzyl salicyl)carbonate,
bis(methyl 4-chlorosalicyl)carbonate and the like.
[0039] Preferably, BSMC is used in melt polycarbonate synthesis due
to its lower molecular weight and higher vapor pressure.
[0040] Some non-limiting examples of non-activating groups which,
when present in an ortho position, would not be expected to result
in activated carbonates are alkyl, cycloalkyl or cyano groups. Some
specific and non-limiting examples of non-activated carbonates
include bis(o-methylphenyl)carbonate, bis(p-cumylphenyl)carbonate,
bis(p-(1,1,3,3-tetramethyl)butylphenyl)carbonate and
bis(o-cyanophenyl)carbonate. Unsymmetrical combinations of these
structures are also expected to result in non-activated
carbonates.
[0041] Unsymmetrical diaryl carbonates, wherein one aryl group is
activated and one aryl is inactivated, are useful if the activating
group renders the diaryl carbonate more reactive than diphenyl
carbonate.
[0042] One method for determining whether a certain diaryl
carbonate is activated or is not activated is to carry out a model
melt transesterification reaction between the particular diaryl
carbonate and a phenol such as para-(1,1,3,3-tetramethyl)butyl
phenol (and comparing the relative reactivity against diphenyl
carbonate). This phenol is preferred because it possesses only one
reactive site, possesses a low volatility, and possesses a similar
reactivity to bisphenol-A. The model melt transesterification
reaction is carried out at temperatures above the melting points of
the particular diaryl carbonate and phenol in the presence of a
transesterification catalyst, which is usually an aqueous solution
of sodium hydroxide or sodium phenoxide. Preferred concentrations
of the transesterification catalyst are at about 0.001 mole percent
based on the number of moles of the phenol or diaryl carbonate.
Although a preferred reaction temperature is 200.degree. C., the
choice of reaction conditions as well as catalyst concentration can
be adjusted depending on the reactivity and melting points of the
reactants to provide a convenient reaction rate. The reaction
temperature is preferably maintained below the degradation
temperature of the reactants. Sealed tubes can be used if the
reaction temperatures cause the reactants to volatilize and affect
the reactant molar balance. A determination of an equilibrium
concentration of the reactants is accomplished through reaction
sampling during the course of the reaction with subsequent analysis
of the reaction mixture using well-known detection methods such as
HPLC (high pressure liquid chromatography). Particular care needs
to be taken so that the reaction does not continue after the sample
has been removed from the reaction vessel. This is accomplished by
cooling down the sample in an ice bath and by employing a reaction
quenching acid, such as acetic acid in the water phase of the HPLC
solvent system. It may also be desirable to introduce the reaction
quenching acid directly into the reaction sample in addition to
cooling the reaction mixture. A preferred concentration for the
reaction quenching acid, e.g., acetic acid in the water phase of
the HPLC solvent system, is about 0.05 mole percent. The
equilibrium constant is then determined from the concentration of
the reactants and product after equilibrium is reached. Equilibrium
is assumed to have been reached when the concentration of
components in the reaction mixture reach a point of little or no
change on sampling of the reaction mixture. The equilibrium
constant can be determined from the concentration of the reactants
and products by methods well known to those skilled in the art. A
diaryl carbonate which possesses a relative equilibrium constant
(K.sub.diarylcarbonate/K.sub.diphenylcarbonate) of greater than 1
is considered to possess a greater reactivity than diphenyl
carbonate and is a suitable activated aromatic carbonate for use in
the present disclosure, whereas a diaryl carbonate which possesses
an equilibrium constant of 1 or less is considered to possess the
same or have less reactivity than diphenyl carbonate and is
considered not to be activated. It is generally preferred to employ
an activated aromatic carbonate with very high reactivity compared
to diphenyl carbonate when conducting transesterification
reactions. Preferred are activated aromatic carbonates with an
equilibrium constant greater than at least 1,000 times that of
diphenyl carbonate.
[0043] Polycarbonate compositions comprising the structural unit of
formula (VII) and carbonate units derived from the activated
carbonate preferably comprise at least one end group derived from
the activated carbonate. In one embodiment, the end groups which
are indicative of the activated aromatic carbonate has a structure
of formula (XII): ##STR20## wherein Q is an ortho-positioned
activating group; A is an aromatic ring, n is a whole number of 1
to the number of replaceable hydrogen groups substituted on the
aromatic ring A; R is a substituent group selected from the group
consisting of alkyl, cycloalkyl, alkoxy, aryl, cyano, nitro, and
halogen; and b is zero to a whole number to the number of
replaceable hydrogen groups on the aromatic ring minus n. Q is
preferably a radical independently selected from the group
consisting of (alkoxycarbonyl)aryl groups, halogens, nitro groups,
amide groups, sulfone groups, sulfoxide groups, or imine groups
with structures ##STR21## wherein X comprises halogen or NO.sub.2,
M and M' independently comprises N-alkyl, N-aryl, or N-alkyl aryl;
R.sup.4 comprises alkyl or aryl when n is 1; and n has a value of 0
or 1.
[0044] Polycarbonates prepared using ester-substituted diaryl
carbonates, such as for example BMSC, may further comprise very low
levels of structural features, which arise from side reactions
taking place during the melt polymerization reaction between an
ester-substituted diaryl carbonate of structure (XI) and dihydroxy
aromatic compounds of structure (VIII). One such structural feature
has a structure of formula (XIII): ##STR22## wherein R.sup.7 is a
halogen atom, cyano group, nitro group, C.sub.1-C.sub.20 alkyl
radical, C.sub.4-C.sub.20 cycloalkyl radical, C.sub.4-C.sub.20
aromatic radical, C.sub.1-C.sub.20 alkoxy radical, C.sub.4-C.sub.20
cycloalkoxy radical, C.sub.4-C.sub.20 aryloxy radical,
C.sub.1-C.sub.20 alkylthio radical, C.sub.4-C.sub.20 cycloalkylthio
radical, C.sub.4-C.sub.20 arylthio radical, C.sub.1-C.sub.20
alkylsulfinyl radical, C.sub.4-C.sub.20 cycloalkylsulfinyl radical,
C.sub.4-C.sub.20 arylsulfinyl radical, C.sub.1-C.sub.20
alkylsulfonyl radical, C.sub.4-C.sub.20 cycloalkylsulfonyl radical,
C.sub.4-C.sub.20 arylsulfonyl radical, C.sub.1-C.sub.20
alkoxycarbonyl radical, C.sub.4-C.sub.20 cycloalkoxycarbonyl
radical, C.sub.4-C.sub.20 aryloxycarbonyl radical, C.sub.2-C.sub.60
alkylamino radical, C.sub.6-C.sub.60 cycloalkylamino radical,
C.sub.5-C.sub.60 arylamino radical, C.sub.1-C.sub.40
alkylaminocarbonyl radical, C.sub.4-C.sub.40
cycloalkylaminocarbonyl radical, C.sub.4-C.sub.40 arylaminocarbonyl
radical, or C.sub.1-C.sub.20 acylamino radical; and c is a whole
number of 1-4. Typically such kinks are present only to a minor
extent (e.g., 0.2 to 1 mole percent).
[0045] Structure (XIII) is termed an internal ester-carbonate
linkage or kink. Without wishing to be bound by any theory, it is
thought that structure (XIII) may arise by reaction of an
ester-substituted phenol by-product, for example methyl salicylate,
at its ester carbonyl group with a dihydroxy aromatic compound or a
hydroxyl group of a growing polymer chain. Further reaction of the
ester-substituted phenolic hydroxy group leads to formation of a
carbonate linkage. Thus, the ester-substituted phenol by-product of
reaction of an ester-substituted diaryl carbonate with a dihydroxy
aromatic compound may be incorporated into the main chain of a
linear polycarbonate, for example.
[0046] Another structural feature present in melt
transesterification polymerization reactions between
ester-substituted diaryl carbonates and dihydroxy aromatic
compounds is the ester-linked terminal end group having a free
hydroxyl group and have the structure (XIV): ##STR23## wherein
R.sup.7 and c are as defined above. Without wishing to be bound by
any theory, it is believed that structure (XIV) may arise in the
same manner as structure (XIII), but without further reaction of
the ester-substituted phenolic hydroxy group. In the structures
provided herein, the wavy line represents the polycarbonate polymer
chain structure. End capping of the polymer chains made by this
method may be only partial. In typical embodiments of
polycarbonates prepared by the methods described herein, the free
hydroxyl group content is from 7 percent to 50 percent. This number
may be varied by changing reaction conditions or by adding
additional end-capping agents. In one embodiment, wherein the
activated carbonate used is BMSC, there will be an ester linked end
group of structure (XV): ##STR24## which possesses a free hydroxyl
group. Thus, for example, if the terminal group of structure (XV)
is attached to a para, para-PPPBP unit in the polycarbonate chain
then it is designated hereinafter as "p,p-PPPBP-salicyl-OH end",
and if the terminal group of structure (XV) is attached to a BPA
unit in the polycarbonate chain, it is hereinafter designated as
"BPA-salicyl-OH end".
[0047] The polycarbonates comprise structural units indicative of
the activated carbonate. These structural units may be end groups
produced when activated carbonate fragments act as end capping
agents or may be kinks introduced into the copolymer by
incorporation of activated carbonate fragments.
[0048] The polycarbonate made, using the activated aromatic
carbonate as described above, may also have end-groups having
structure (XVI): ##STR25## where R, b, A, Q, and n are defined in
the preceding sections.
[0049] In one embodiment the terminal end group having structure
(XVI) is a methyl salicyl group of structure (XVII): ##STR26## It
could also include other salicyl groups such as the ethylsalicyl,
isopropylsalicyl, and butylsalicyl groups.
[0050] A number of polymerization methods can be used for producing
a polymer, such as a homopolycarbonate or a copolycarbonate,
comprising structural units derived from a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to about 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of the purified
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. Suitable methods
for fabricating polycarbonates, for example, include a melt
transesterification polymerization method, an interfacial
polymerization method, and a bischloroformate polymerization
method.
[0051] As used herein, the term "structural units derived from"
when used in the context of describing the portions of the
copolycarbonates derived from the aliphatic diol and the aromatic
dihydroxy compounds refers to the fact that both such monomers lose
their respective hydrogen atoms upon incorporation in the
polymer.
[0052] As used herein the term "activated carbonate" refers to a
diaryl carbonate which is typically more reactive (either
kinetically or thermodynamically) toward aromatic dihydroxy
compounds than diphenyl carbonate under identical conditions.
Activated carbonates are typically (but not necessarily)
substituted diaryl carbonates.
[0053] As used herein the term "structural units indicative of the
activated carbonate" means either internal "kinks" in the
copolycarbonate or end groups caused by incorporation of a fragment
of an activated carbonate such as bismethylsalicyl carbonate
(sometimes hereinafter referred to as "BMSC").
[0054] The melt transesterification polymerization method is
generally carried out by combining a catalyst and a reactant
composition to form a reaction mixture; and mixing the reaction
mixture under reactive conditions for a time period effective to
produce a polycarbonate product, wherein the reactant composition
generally comprises a carbonic acid diester of the formula
(ZO).sub.2C.dbd.O, wherein each Z is independently an unsubstituted
or a substituted alkyl radical, or an unsubstituted or a
substituted aryl radical and the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less
than or equal to about 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of said
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
[0055] During the manufacture of the polycarbonates by the melt
transesterification method using the activated or unactivated
carbonic acid diester, the amount of the carbonic acid diester
comprises about 0.8 moles to about 1.30 moles, and more
specifically about 0.9 moles to about 1.2 moles, based on one mole
of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine or any
combination of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine and at least one
aromatic dihydroxy comonomer.
[0056] Suitable melt transesterification catalysts include alkali
metal compounds, alkaline earth metal compounds,
tetraorganoammonium compounds, and tetraorganophosphonium
compounds, combinations comprising at least one of the foregoing
catalysts.
[0057] Specific examples of alkali metal compounds or alkaline
earth metal compounds include organic acid salts, inorganic acid
salts, oxides, hydroxides, hydrides, and alcoholates of alkali
metals and alkaline earth metals. Preferably, the catalyst is an
alkali metal compound of the formula M.sub.1X.sub.1, wherein
M.sub.1 is selected from the group consisting of lithium, sodium,
and potassium; and XI is selected from the group consisting of
hydroxide and OAr, wherein Ar is a monovalent aromatic radical.
[0058] More specifically, examples of suitable alkali metal
compounds include, but are not limited to, sodium hydroxide,
potassium hydroxide, lithium hydroxide, calcium hydroxide,
magnesium hydroxide, sodium bicarbonate, potassium bicarbonate,
lithium bicarbonate, sodium carbonate, potassium carbonate, lithium
carbonate, sodium acetate, potassium acetate, lithium acetate,
lithium stearate, sodium stearate, potassium stearate, lithium
hydroxyborate, sodium hydroxyborate, sodium phenoxyborate, sodium
benzoate, potassium benzoate, lithium benzoate, disodium hydrogen
phosphate, dipotassium hydrogen phosphate, dilithium hydrogen
phosphate, disodium salts, dipotassium salts, and dilithium salts
of bisphenol A, and sodium salts, potassium salts, lithium salts of
phenol, and the like.
[0059] Specific examples of alkaline earth metal compounds include,
but are not limited to, calcium hydroxide, barium hydroxide,
magnesium hydroxide, strontium hydroxide, calcium bicarbonate,
barium bicarbonate, magnesium bicarbonate, strontium bicarbonate,
calcium carbonate, barium carbonate, magnesium carbonate, strontium
carbonate, calcium acetate, barium acetate, magnesium acetate,
strontium acetate, strontium stearate, and the like.
[0060] Exemplary tetraorganoammonium compounds include compounds
comprising structure (XVIII): ##STR27## wherein R.sup.8-R.sup.11
are independently a C.sub.1-C.sub.20 alkyl radical,
C.sub.4-C.sub.20 cycloalkyl radical or a C.sub.4-C.sub.20 aryl
radical and X.sup.- is an organic or inorganic anion. Suitable
anions (X.sup.-) include hydroxide, halide, carboxylate, sulfonate,
sulfate, carbonate and bicarbonate. In one embodiment, the
transesterification catalyst comprises tetramethyl ammonium
hydroxide.
[0061] In still other embodiments, the catalyst is a
tetraorganophosphonium compound. Exemplary quaternary phosphonium
compounds include compounds comprising structure (XIX): ##STR28##
wherein R.sup.8-R.sup.11 and X.sup.- are as previously described.
Illustrative anions include hydroxide, halide, carboxylate,
sulfonate, sulfate, carbonate, and bicarbonate.
[0062] Where X.sup.- is a polyvalent anion such as carbonate or
sulfate it is understood that the positive and negative charges in
structures (XVIII) and (XIX) are properly balanced. For example,
when R.sup.9-R.sup.12 in structure (XVIII) are each methyl groups
and X.sup.- is carbonate, it is understood that X.sup.- represents
1/2 (CO.sub.3.sup.-2) as will be appreciated by those skilled in
the art.
[0063] Specific examples of tetraorganoammonium compounds and
tetraorganophosphonium compounds include, but are not limited to
tetramethylammonium hydroxide, tetrabutylammonium hydroxide,
tetraethylphosphonium hydroxide, tetrabutylphosphonium acetate,
tetrabutylphosphonium hydroxide, and the like.
[0064] In one embodiment, the catalyst comprises tetrabutyl
phosphonium acetate. In an alternate embodiment, the catalyst
comprises a mixture of an alkali metal salt or alkaline earth metal
salt with at least one quaternary ammonium compound, at least one
quaternary phosphonium compound, or a mixture thereof. For example,
the catalyst may be a mixture of sodium hydroxide and tetrabutyl
phosphonium acetate. In another embodiment, the catalyst is a
mixture of sodium hydroxide and tetramethyl ammonium hydroxide.
[0065] In another embodiment, the catalyst comprises an alkaline
earth metal salt of an organic acid, an alkali metal salt of an
organic acid, or a salt of an organic acid comprising both alkaline
earth metal ions and alkali metal ions. Alkali metal and alkaline
earth metal salts of organic acids, such as for example, formic
acid, acetic acid, stearic acid and ethylenediamine tetraacetic
acid can also be used. In one embodiment, the catalyst comprises
magnesium disodium ethylenediamine tetraacetate (EDTA magnesium
disodium salt).
[0066] In yet another embodiment, the catalyst comprises the salt
of a non-volatile inorganic acid. By "non-volatile" it is meant
that the referenced compounds have no appreciable vapor pressure at
ambient temperature and pressure. In particular, these compounds
are not volatile at temperatures at which melt polymerizations of
polycarbonate are typically conducted. The salts of non-volatile
acids are alkali metal salts of phosphites; alkaline earth metal
salts of phosphites; alkali metal salts of phosphates; and alkaline
earth metal salts of phosphates. Suitable salts of non-volatile
acids include NaH.sub.2PO.sub.3, NaH.sub.2PO.sub.4,
Na.sub.2H.sub.2PO.sub.3, KH.sub.2PO.sub.4, CsH.sub.2PO.sub.4,
Cs.sub.2H.sub.2PO.sub.4, or a mixture thereof. In one embodiment,
the transesterification catalyst comprises both the salt of a
non-volatile acid and a basic co-catalyst such as an alkali metal
hydroxide. This concept is exemplified by the use of a combination
of NaH.sub.2PO.sub.4 and sodium hydroxide as the
transesterification catalyst.
[0067] Any of the catalysts disclosed above may be used as
combinations of two or more substances. The catalyst may be added
in a variety of forms. The catalyst may be added as a solid, for
example as a powder, or it may be dissolved in a solvent, for
example, in water or alcohol. The total catalyst composition is
preferably about 1.times.10.sup.-7 to about 2.times.10.sup.-3
moles, and with about 1.times.10.sup.-6 to about 4.times.10.sup.-4
moles more preferred for each mole of the combination of the
purified para, para-PPPBP and the aromatic dihydroxy compound
comonomer.
[0068] Any of the catalysts described above for use in
polycarbonate melt transesterification reactions may be used in
reactions involving activated carbonates. It is often advantageous
to use a combination of some amount of a salt of an alkaline earth
metal and/or an alkali metal (i.e., an "alpha" catalyst) that does
not degrade at temperatures used throughout the reaction together
with a quaternary ammonium and/or a quaternary phosphonium compound
that does degrade at a temperature used in the reaction (i.e., a
"beta" catalyst). The total amount of catalyst employed is about
1.times.10.sup.-7 to about 1.times.10.sup.-2, and preferably about
1.times.10.sup.-7 to about 2.times.10.sup.-3 moles catalyst per
total moles of the mixture of para, para-PPPBP and aromatic
dihydroxy compound employed.
[0069] The reactants for the polymerization reaction using an
activated aromatic carbonate can be charged into a reactor either
in the solid form or in the molten form. Initial charging of
reactants into a reactor and subsequent mixing of these materials
under reactive conditions for polymerization may be conducted in an
inert gas atmosphere such as a nitrogen atmosphere. The charging of
one or more reactant may also be done at a later stage of the
polymerization reaction. Mixing of the reaction mixture is
accomplished by any methods known in the art, such as by stirring.
Reactive conditions include time, temperature, pressure and other
factors that affect polymerization of the reactants. Typically, the
activated aromatic carbonate is added at a mole ratio of about 0.8
to about 1.3, and more specifically, 0.9 to about 1.2 and all
sub-ranges there between, relative to the total moles of aromatic
dihydroxy compound and aliphatic diol.
[0070] The melt polymerization reaction using the activated
aromatic carbonate is conducted by subjecting the above reaction
mixture to a series of temperature-pressure-time protocols. In some
embodiments, this involves gradually raising the reaction
temperature in stages while gradually lowering the pressure in
stages. In one embodiment, the pressure is reduced from about
atmospheric pressure at the start of the reaction to about 0.01
millibar (1 Pascal) or in another embodiment to 0.05 millibar (5
Pascals) in several steps as the reaction approaches completion.
The temperature may be varied in a stepwise fashion beginning at a
temperature of about the melting temperature of the reaction
mixture and subsequently increased to about 320.degree. C. In one
embodiment, the reaction mixture is heated from about ambient
(about 21-23.degree. C.) temperature to about 150.degree. C. The
polymerization reaction starts at a temperature of about
150.degree. C. to about 220.degree. C., then is increased to about
220.degree. C. to about 250.degree. C. and is then further
increased to a temperature of about 250.degree. C. to about
320.degree. C. and all sub-ranges there-between. The total reaction
time is about 30 minutes to about 200 minutes and all sub-ranges
there between. This procedure will generally ensure that the
reactants react to give polycarbonates with the desired molecular
weight, glass transition temperature and physical properties. The
reaction proceeds to build the polycarbonate chain with production
of a by-product such as, for example an ester-substituted alcohol
e.g., methyl salicylate. Efficient removal of the by-product may be
achieved by different techniques such as reducing the pressure.
Generally the pressure starts relatively high in the beginning of
the reaction, such as atmospheric pressure in one embodiment, and
is lowered progressively throughout the reaction and temperature is
raised throughout the reaction. Experimentation is needed to find
the most efficient conditions for particular production
equipment.
[0071] The progress of the reaction may be monitored by measuring
the melt viscosity or the weight average molecular weight of the
reaction mixture using techniques known in the art such as gel
permeation chromatography. These properties may be measured by
taking discreet samples or may be measured on-line. After the
desired melt viscosity and/or molecular weight is reached, the
final polycarbonate product may be isolated from the reactor in a
solid or molten form. It will be appreciated by a person skilled in
the art, that the method of making polycarbonates as described in
the preceding sections may be made in a batch or a continuous
process and the process disclosed herein is essentially preferably
carried out in a solvent free mode. Reactors chosen should ideally
be self-cleaning and should minimize any "hot spots."
[0072] In one embodiment, the aliphatic homopolycarbonate and
aliphatic-aromatic copolycarbonate may be prepared in an extruder
in presence of one or more catalysts, wherein the carbonating agent
is an activated aromatic carbonate. The reactants for the
polymerization reaction can be fed to the extruder in powder or
molten form. In one embodiment, the reactants are dry blended prior
to addition to the extruder. The extruder may be equipped with
pressure reducing devices (e.g., vents), which serve to remove the
activated phenol by-product and thus drive the polymerization
reaction toward completion. The molecular weight of the
polycarbonate product may be manipulated by controlling, among
other factors, the feed rate of the reactants, the type of
extruder, the extruder screw design and configuration, the
residence time in the extruder, the reaction temperature and the
pressure reducing techniques present on the extruder. The molecular
weight of the polycarbonate product may also depend upon the
structures of the reactants, such as, activated aromatic carbonate,
aliphatic diol, dihydroxy aromatic compound, and the catalyst
employed. Many different screw designs and extruder configurations
are commercially available that use single screws, double screws,
vents, back flight and forward flight zones, seals, side-streams
and sizes. One skilled in the art may have to experiment to find
the best designs using generally known principals of commercial
extruder design. Vented extruders similar to those that are
commercially available may also be used.
[0073] The process disclosed herein can be used to prepare PPPBP
homopolycarbonate and copolycarbonates having a weight average
molecular weight (Mw) of about 3,000 to about 150,000 and a glass
transition temperature (Tg) of about 80.degree. C. to about
300.degree. C. The number average molecular weights (Mn) of the
homopolycarbonate and copolycarbonates is from about 1,500 to about
75,000. The transparency of cast films made from the polycarbonate
or copolycarbonates prepared in accordance with the present
disclosure is greater than about 85 percent, as determined by a
Haze Guard Instrument.
[0074] In monitoring and evaluating polycarbonate synthesis, it is
of particular interest to determine the concentration of Fries
product present in the polycarbonate. The generation of significant
Fries product can lead to polymer branching, resulting in
uncontrollable melt behavior. In the process of preparing
polycarbonates described herein, some branching reaction (Fries
reaction) takes place (especially at higher temperatures and
exacerbated by alpha catalysts) resulting in a Fries product. Fries
products are defined as structural units of the product
polycarbonate which upon hydrolysis of the product polycarbonate
affords a carboxy-substituted dihydroxy aromatic compound bearing a
carboxy group adjacent to one or both of the hydroxy groups of the
carboxy-substituted dihydroxy aromatic compound. For example, in
bisphenol A polycarbonate prepared by a melt polymerization method
in which Fries reaction occurs, the Fries product comprises
structure (XX) below, which affords 2-carboxy bisphenol A upon
complete hydrolysis of the product polycarbonate. As indicated, the
Fries product may serve as a site for polymer branching, the wavy
lines of structure (XX) indicating a polymer chain structure.
##STR29##
[0075] The polycarbonates prepared using the activated carbonate by
the disclosed method have a concentration of Fries product of less
than about 500 parts per million (ppm) as measured by high
performance liquid chromatography (HPLC). The Fries concentration
is much less than what is obtained in a conventional melt
polymerization process that uses diphenyl carbonate as the carbonic
acid diester. Fries products are generally undesirable for certain
polycarbonates because excessive levels can adversely affect
certain physical properties.
[0076] In the interfacial polymerization method,
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, with or without
one or more comonomers, and phosgene are reacted in the presence of
an acid acceptor and an aqueous base to produce said polycarbonate.
Tertiary amines, such as for example, trialkylamines are preferably
used as acid acceptors. An exemplary trialkylamine is
triethylamine. Suitable aqueous bases include, for example, the
alkali metal hydroxides, such as sodium hydroxide. The interfacial
method can be used for producing polycarbonates comprising
structural units derived from
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, and preferably
having molecular weights greater than about 50,000, relative to
polystyrene standard.
[0077] The interfacial method described above can be suitably
adapted to produce polycarbonates through the intermediate
formation of 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
bischloroformate. This method is sometimes called the
bischloroformate polymerization method. In one embodiment, the
method comprises reacting a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine with phosgene in
an organic solvent, and then reacting the bischloroformate either
with a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, or an
aromatic dihydroxy compound in the presence of an acid acceptor and
an aqueous base to form the polycarbonate.
[0078] The interfacial polymerization method and the
bischloroformate polymerization method can be carried in a batch or
a continuous mode using one or more reactor systems. To carry out
the process in a continuous mode, one or more continuous reactors,
such as for example, a tubular reactor can be used. In one
embodiment, the continuous method comprises introducing into a
tubular reactor system phosgene, at least one solvent (example,
methylene chloride), at least one bisphenol, aqueous base, and
optionally one or more catalysts (example, a trialkylamine) to form
a flowing reaction mixture. The flowing mixture is then passed
through the tubular reactor system until substantially all of the
phosgene has been consumed. The resulting mixture is next treated
with a mixture comprising an aqueous base, at least one end-capping
agent, optionally one or more solvents, and at least one catalyst.
The end-capped polycarbonate thus formed is continuously removed
from the tubular reactor system. The process can be used for
preparing end-capped polycarbonate oligomers (generally
polycarbonates having a weight average molecular weight of less
than or equal to 10,000 daltons) or polymers having a weight
average molecular weight of greater than 10,000 daltons. The
processes outlined hereinabove can also be suitably adapted, for
example, to produce end-capped polycarbonates via the intermediate
formation of a mixture comprising a bisphenol monochloroformate or
a bisphenol bischloroformate.
[0079] In another embodiment, polymer blends comprise the polymers
described previously and at least one thermoplastic polymer. The at
least one thermoplastic polymer is selected from the group
consisting of vinyl polymers, acrylic polymers, polyacrylonitrile,
polystyrenes, polyolefins, polyesters, polyurethanes, polyamides,
polysulfones, polyimides, polyetherimides, polyphenylene ethers,
polyphenylene sulfides, polyether ketones, polyether ether ketones,
ABS resins, polyethersulfones, poly(alkenylaromatic) polymers,
polybutadiene, polyacetals, polycarbonates, polyphenylene ethers,
ethylene-vinyl acetate copolymers, polyvinyl acetate, liquid
crystal polymers, ethylene-tetrafluoroethylene copolymer, aromatic
polyesters, polyvinyl fluoride, polyvinylidene fluoride,
polyvinylidene chloride, tetrafluoroethylene,
polycarbonate--polyorganosiloxane block copolymers, copolymers
comprising aromatic ester, estercarbonate, and carbonate repeat
units; mixtures, and blends comprising at least one of the
foregoing polymers.
[0080] The polymers and polymer blends described hereinabove are
valuable for producing articles. In one embodiment, an article
comprises a polymer comprising structural units derived from a
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which comprises
less than or equal to about 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine,
relative to an overall weight of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. In another
embodiment, an article comprises a polymer comprising structural
units derived from a
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, which comprises
less than or equal to about 1,000 parts per million of
2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine,
relative to an overall weight of said
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
[0081] Polymers, particularly polycarbonate homopolymers and
copolymers comprising structural units derived from the high purity
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in general, and
para,para-PPPBP in particular have a yellowness index of less than
10 as measured on a 3 millimeter thick plaque in accordance with
ASTM D1925 in one embodiment, less than 5 in another embodiment,
and less than 2 in still another embodiment. Hence these
polycarbonate polymers are useful for producing articles having a
number of useful properties, such as a low residual color. The
articles also exhibit excellent heat aging. Thus, extruded articles
have low color values (as measured by yellowness index, YI) even
after heat aging, such as, for example, a YI of less than about 2
after heat aging in air at 155.degree. C.-160.degree. C. for about
500 hours in one embodiment, and a YI of less than about 0.5 after
heat aging in air at 120.degree. C. for about 500 hours in another
embodiment. The polycarbonate homopolymers and copolymers have high
glass transition temperatures of higher than or equal to about
180.degree. C. One of the unique properties of these
polycarbonates, especially those that have glass transition
temperatures of greater than or equal to about 180.degree. C. is
that during melt processing they exhibit a shear-thinning behavior.
That is, the polymers have the ability to flow under an applied
shear. Therefore, standard melt processing equipment used for BPA
polycarbonates can advantageously be used for producing articles.
The polycarbonates also have high transparency, as measured by
percent light transmission, of greater than or equal to about 85
percent. Moreover, the copolycarbonate is especially useful for
articles that are preferably made form a polymer having
transparency and the other advantageous properties of a BPOA
homopolymer polycarbonate but with a significantly higher Tg.
Lenses in applications where they are exposed to heat are a good
example of such an application.
[0082] The polycarbonate compositions disclosed herein are
particularly valuable for producing a variety of lenses suitable
for diverse applications. In an embodiment, the lens comprises a
polycarbonate, which comprises structural units of formula (VII)
derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine
comprising less than or equal to about 1,000 parts per million of a
2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
relative to an overall weight of said
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; and a yellowness
index of less than 10 as measured on a 3 millimeter thick plaque in
accordance with ASTM D1925 in one embodiment, and less than 2 in
another embodiment. Non-limiting examples of suitable articles
include an automotive headlamp inner lens, an automotive headlamp
outer lens, an automotive fog lamp lens, an automotive bezel, a
medical device, a display device, electrical connectors, under the
hood automotive parts, and projector lens. Examples of suitable
display devices include a laptop computer screen, a liquid crystal
display screen, and an organic light-emitting diode display
screen.
[0083] The polycarbonates disclosed herein may also be combined
with effective amounts of one or more of various types of additives
used selected from the group consisting of fillers, fire
retardants, drip retardants, antistatic agents, UV stabilizers,
heat stabilizers, antioxidants, plasticizers, dyes, pigments,
colorants, processing aids, and mixtures thereof. These additives
are known in the art, as are their effective levels and methods of
incorporation. Effective amounts of the additives vary widely, but
they are usually present in an amount up to about 50% or more by
weight, based on the weight of the entire composition. Especially
preferred additives include hindered phenols, thio compounds and
amides derived from various fatty acids. The preferred amounts of
these additives generally ranges up to about 2% total combined
weight based on the total weight of the composition.
EXAMPLES
[0084] In the following examples, molecular weights were measured
by gel permeation chromatography using a polystyrene standard.
Glass transition temperatures of the polycarbonates were measured
by differential scanning calorimetry by heating the sample at the
rate of 10.degree. C. to 20.degree. C. per minute under nitrogen.
Yellow index was measured using ASTM D1925 test method on plaques
of 3 millimeter thickness and on films of 0.2 millimeter thickness.
Films were prepared in a Petri dish by casting from a solution of
1.1 grams of a polycarbonate in about 10 milliliters of
chloroform.
[0085] HPLC analysis was generally carried out by using a solution
of about 50 milligrams of the sample dissolved in about 10
milliliters of methanol. The HPLC instrument was equipped with a
C18 (reverse phase) column maintained at a temperature of
40.degree. C., and an ultraviolet detector capable of detecting
components at a wavelength of 230 nanometers. A solvent mixture of
methanol and water of varying relative proportions was used. The
flow rate was maintained at 1 milliliter per minute. Area percent
assay was computed from the area value for each peak detected in
the chromatogram divided by the total area from all peaks detected.
To measure weight percent assay, calibration curves for p,p-PPPBP,
o,p-PPPBP, and phenolphthalein were first generated. Then the
weight percent of a given component in a sample was calculated
using these calibration curves.
[0086] All melt transesterification polymerizations were carried
out using either diphenyl carbonate or bismethylsalicyl carbonate.
The catalyst for all of the polymerization runs was prepared by
taking appropriate aliquots of a stock solution of aqueous sodium
hydroxide and a 25 weight percent aqueous tetramethylammonium
hydroxide. Molded articles were prepared by first preparing pellets
of the molding compositions using a 25 millimeter ZSK twin-screw
extruder, followed by injection molding using a L&T DEMAG 60
molding machine having a clamping capacity of 60 ton, a screw
diameter of 25 millimeters, and shot capacity of 58 grams of
polystyrene.
Comparative Example 1
[0087] In this example, a prior art process was employed to isolate
a para, para-PPPBP product.
[0088] The prior art process included refluxing a mixture of
phenolphthalein (20 grams (g)), aniline hydrochloride (20 g), and
60 ml of aniline at a temperature from about 180.degree. C. to
about 185.degree. C. for 5 hours under nitrogen. The dark solution
was then stirred into a mixture of 100 grams of ice and 70 grams of
concentrated HCl. The violet crystalline product was filtered off
and washed with water. The crystals were then dissolved in ice-cold
10% sodium hydroxide solution. The solution was treated with 0.2 g
active carbon, and then filtered. By drop-wise addition of
concentrated HCl into the stirred batch, the color changed to a
bright pink, then to a pure white, thick slurry with a pH of 3-4.
The precipitated phenolphthalein anilide was then washed neutral
with water and dried under vacuum at 70.degree. C. The crude
crystals gave a melting point of 288-291.degree. C. with a yield of
79%. Double recrystallization from ethanol, followed by drying the
crystals under vacuum at 150.degree. C. gave the product. The
results are shown in Table 1.
Comparative Example 2
[0089] The procedure described in Comparative Example 1 was
repeated except that the water by-product was removed. The results
are shown in Table 1.
Comparative Example 3
[0090] In this Example, phenolphthalein and aniline were reacted in
the presence of hydrochloric acid. The reaction was carried out
without removing the water by-product.
[0091] Phenolphthalein (38.1 grams), aniline (65 milliliters), and
concentrated hydrochloric acid (20.5 milliliters) were charged into
a reaction vessel and heated such that the temperature of the
reaction mixture was 155.degree. C.-165.degree. C. The temperature
of the reaction was adjusted to 155-165.degree. C. After being
heated for about 14-15 hours, the reaction mixture was poured into
a mixture of hydrochloric acid and water. The solid product, which
precipitated, was collected by filtration. Analysis of the solid
product by HPLC indicated about 6 area percent of para,para-PPPBP
and about 93 area percent of phenolphthalein, wherein ortho,
para-PPPBP was not detected (less than 10 parts per million, the
detection limit of the HPLC method). The results are shown in Table
1.
Comparative Examples 4 and 5
[0092] Polymerization runs were carried out using the procedure
described in Example 2 below with the para,para-PPPBP prepared in
accordance with Comparative Examples 1 and 2, respectively. The
molecular weights of the polycarbonate prepared by this method and
the YI of films prepared by solution casting of the polycarbonates
are shown in Table 2.
Comparative Example 6
[0093] This Example describes the preparation of a polycarbonate
copolymer using the same method as disclosed in Example 4 below,
with a para, para-PPPBP monomer prepared in accordance with
Comparative Example 2.
Example 1
[0094] This Example describes the preparation of para,para-PPPBP
containing less than or equal to about 1,000 parts per million of
ortho, para-PPPBP isomer impurity.
[0095] Phenolphthalein (31.8 grams), aniline (65 milliliters), and
concentrated hydrochloric acid (20.5 milliliters) were taken in a
reaction flask fitted with a Dean Stark condenser. The reaction
mass was heated to an internal temperature of 155.degree.
C.-165.degree. C. Water was collected during the course of the
reaction. After being heated at this temperature for 14-15 hours,
the reaction mixture was poured into a mixture of hydrochloric acid
and water. The crude product, which precipitated, was collected by
filtration and dissolved in an aqueous sodium hydroxide solution
containing activated charcoal. After being stirred for about 30
minutes, the mixture was then filtered to remove the charcoal. The
charcoal treatment step was repeated once more, and the resulting
filtrate was treated with concentrated hydrochloric acid to
precipitate para, para-PPPBP as a white solid, which was then
filtered. The solid product was refluxed in methanol (approximately
four volumes of methanol were taken relative to the volume of the
solid product) for about an hour, cooled, and filtered to provide
the final product which was found by HPLC analysis to have a para,
para-PPPBP purity of 99.9 area percent. The yield of the isolated
product was 80 to 82 percent of theory. The results are shown in
Table 1, where "ND" indicates, "not detected".
Example 2
[0096] This Example describes the general melt transesterification
method used for preparing polycarbonate copolymers using 47 weight
percent of diphenyl carbonate and 53 weight percent of a monomer
mixture consisting of 75 weight percent of BPA and 25 weight
percent of the purified para,para-PPPBP prepared in accordance with
Example 1.
[0097] A glass polymerization reactor was passivated by soaking the
reactor in a bath containing 1 molar aqueous hydrochloric acid
solution. After 24 hours, the reactor was thoroughly rinsed with
demineralized water, and finally, with deionized water to ensure
that all traces of acid and other contaminants were removed. The
reactor was then thoroughly dried and charged with the appropriate
amounts of the purified para,para-PPPBP monomer or a monomer
mixture comprising the purified para,para-PPPBP and diphenyl
carbonate monomers. The reactor was then mounted in a
polymerization assembly and checked to ensure that no leaks were
present. The catalyst solutions (2.5.times.10.sup.-4 mol of aqueous
tetramethylammonium hydroxide and 5.times.10.sup.-6 mole of aqueous
sodium hydroxide), as prepared above, were then introduced into the
reactor using a syringe. The atmosphere inside the reactor was then
evacuated using a vacuum source and purged with nitrogen. This
cycle was repeated 3 times after which the contents of the reactor
were heated to melt the monomer mixture. When the temperature of
the mixture reached about 180.degree. C. to about 190.degree. C.,
the stirrer in the reactor was turned on and adjusted to about 40
to about 80 revolutions per minute (rpm) to ensure that the entire
solid mass fully melted, a process that usually took about 15 to
about 20 minutes. Next, the reaction mixture was heated to a
temperature of about 230.degree. C., while the pressure inside the
reactor was adjusted to about 170 millibar using a vacuum source.
This temperature-pressure-time regime was designated as PI. After
stirring the reaction mass at this condition for about 1 hour, the
reaction temperature was raised to about 270.degree. C. while
readjusting the pressure to around 20 millibar. After being
maintained at this condition, designated as P2, for about 30
minutes, the temperature of the reaction mixture was raised to
300.degree. C. while bringing the pressure down to less than or
equal to about 1 millibar. After being maintained at this
condition, designated as P3, for about 30 minutes, the temperature
of the reaction mixture was raised to 300.degree. C. while bringing
the pressure down to less than or equal to about 1 millibar. After
being maintained at this condition, designated as P4, for about 30
minutes, the temperature of the reaction mixture was raised to
about 315.degree. C. while bringing the pressure down to less than
or equal to about 1 millibar. After allowing the reaction to
proceed under these conditions, designated as P5, for about 10
minutes to about 20 minutes, the pressure inside the reactor was
brought to atmospheric pressure and the reactor was vented to
relieve any excess pressure. Product isolation was accomplished by
breaking the glass nipple at the bottom of the reactor and
collecting the material. In the cases where the product was of a
very high molecular weight, the hot molten polymer was dropped down
by pressurizing the reactor with nitrogen gas.
Example 3
[0098] This Example describes the melt transesterification method
used for preparing polycarbonate copolymer using 55 weight percent
of bismethylsalicyl carbonate and 45 weight percent of a monomer
mixture comprising 75 weight percent of BPA and 25 weight percent
of purified para,para-PPPBP (prepared as described in Example 1).
The polymerization runs were carried using
[0099] The same procedure as described above was used to charge the
necessary reaction ingredients into the reactor. However, after the
heating step to fully melt the monomer, the reaction mixture was
heated to a temperature of about 210.degree. C. at atmospheric
pressure (about 910 millibar). After stirring the reaction mass at
this condition for about 10 minutes, the pressure was reduced to
about 100 millibars, and maintained at this condition for about 15
minutes. Next, the reaction mixture was heated to a temperature of
about 310.degree. C. while bring the pressure down to less than or
equal to about 1 millibar. After being stirred under these
conditions for about 15 minutes, the pressure inside the reactor
was brought to atmospheric pressure and the reactor was vented to
relieve any excess pressure. Product isolation was accomplished
using the same procedure as described in Example 2.
[0100] The procedure described hereinabove was used to prepare
polycarbonate copolymers having M.sub.w from about 45,000 to about
75,000.
Example 4
[0101] This Example describes the general procedure for the
interfacial polymerization method using a monomer mixture
comprising a 75:25 mole ratio of purified para,para-PPPBP (prepared
in accordance with method described in Example 1) and BPA,
respectively. The procedure used here is as described in U.S. Pat.
No. 5,804,525, where the monomer mixture (as described above) and
para-cumylphenol was reacted with phosgene in methylene chloride in
the presence of tetrabutylammonium bromide. During addition of
phosgene, the pH of the reaction mixture was maintained at about
10.5 by slow addition of aqueous sodium hydroxide. After phosgene
addition, triethylamine was added to react out trace levels of
chloroformate derivatives present in the reaction mixture. The
polycarbonate thus prepared had the following physical properties:
YI (yellowness index, ASTM D1925): 9; Notched Izod at ambient
temperature (ASTM D256): 4.9 foot-pound per inch; Glass transition
temperature: 191.degree. C.; Delta YI (ASTM D1925) of molded
article after heat aging in air in an oven maintained at
155.degree. C.-160.degree. C. for 500 hours: less than 2; Delta YI
(ASTM D1925) after heat aging in air in an oven maintained at
120.degree. C. for 500 hours: less than 0.5. TABLE-US-00001 TABLE 1
HPLC analysis (Area percent) Example para,para-PPPBP
Phenolphthalein ortho,para-PPPBP 1* 97.5 0.5 2 2* 98.5 0.11 1.35 3*
6.2 93.1 ND 1 99.9 0.05 ND *Indicates Comparative Example.
[0102] TABLE-US-00002 TABLE 2 Polymeri- para,para- M.sub.w of
zation PPPBP polycar- Run Example Example bonate YI of
polycarbonate Number Number (Daltons) (article) 4* 1* 21,000 6.3
(film) 5* 2* 19,000 4.3 (film) 2 1 30,000 0.8 (film) 3 1 63,000 0.6
(film) 4 1 62,000 <1 (film); 9 (molded plaque) 6* 2* 44,000 59
(molded plaque) *Indicates Comparative Example.
[0103] Table 1 shows the effect of the purity of the
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines on the molecular
weight and yellowness indices of films of the polymers derived
using these phthalimidines as a comonomer with bisphenol A.
Comparative Examples 1 and 2 indicate that a higher level of the
2-hydrocarbyl-3,3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine
impurity (or sometimes herein generally referred to as "ortho,
para-PPPBP impurity") in the para,para-PPPBP comonomer results in a
lower molecular weight and a relatively higher film yellowness
index for the polymer. Without wishing to be bound by theory,
applicants believe that the ortho, para impurity, being relatively
more sterically hindered than the corresponding
para,para-phthalimidine isomer acts as a chain termination agent,
thereby limiting polymer chain length and molecular weight.
However, Example 1 shows that when para,para-PPPBP with no
detectable (by HPLC) level of the ortho, para-impurity is
copolymerized with BPA, the polymer weight average molecular weight
is substantially higher (31,000). Furthermore, the polymer film has
a relatively much lower yellowness index of 0.8. Comparative
Example 3 shows that even if the reaction temperature is maintained
at about 155.degree. C. to 165.degree. C., if water is not removed
during the reaction to form para,para-PPPBP, the reaction gives a
very poor yield (about 6 area percent) of para,para-PPPBP.
[0104] Moreover, when the compound (IV) was prepared in accordance
with the procedure of Comparative Example 1, wherein
phenolphthalein and excess aniline are heated under reflux in a
nitrogen atmosphere for about 5 hours without removal of water,
such that the reaction temperature is about 180.degree. C. to about
185.degree. C., the para, para-PPPBP that was isolated after the
double crystallization from ethanol contained about 2.5 area
percent of an undesired side-product that has been analytically
determined to be isomeric ortho, para-PPPBP.
[0105] On the other hand, if the reaction is carried out in the
same manner as described in Comparative Example 1, but the water
by-product is distilled out over the same period of about 5 hours,
HPLC analysis indicated that the isolated product contains about
98.5 area percent of para,para-PPPBP, about 0.11 area percent of
phenolphthalein, and about 1.35 area percent of the impurity
compound (IV). This indicates that water removal is necessary to
lower the formation of compound (IV). However, when the reaction is
conducted using a reaction temperature of about 160.degree. C. to
about 165.degree. C., water removal takes about 14 hours, and the
impurity (IV) was undetectable in the isolated para, para-PPPBP
product relative to the measurement sensitivity of the HPLC method
(detection limit of 10 parts per million for compound (IV)).
Furthermore, the product only contains about 0.05 area percent of
phenolphthalein. In contrast, when the reaction was conducted at a
reaction temperature of about 160.degree. C. to about 165.degree.
C., but the water was not removed, HPLC analysis of the reaction
mixture after 14 hours of heating indicated formation of only about
6.2 area percent of para, para-PPPBP with the majority (about 92
area percent) of phenolphthalein starting material remaining
unreacted. These results clearly indicate that the preferred method
for forming para, para-PPPBP in high isolated yield and high
isomeric purity is to maintain the reaction temperature at about
160.degree. C. to about 165.degree. C. with water removal over a
period of about 14 hours. Under such conditions, utilization of
phenolphthalein for selectively forming para, para-PPPBP is
enhanced, and formation of the ortho, para-PPPBP is minimized.
These techniques can be suitably adapted to prepare the other
2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines described
previously.
[0106] The results shown in Table 1 (Example 1), and Table 2,
(Examples 2 and 4) clearly indicate that purified para,para-PPPBP
is useful for preparing polycarbonates of high molecular weight
(e.g., M.sub.w of 62,000), which are valuable for producing films
and molded articles having a yellowness index of less than 10.
Moreover, the molded articles show excellent resistance to heat
aging, as shown in Example 4, thus making such polycarbonates
valuable for high heat applications.
[0107] While the disclosure has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the disclosure. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
disclosure without departing from essential scope thereof.
Therefore, it is intended that the disclosure not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the disclosure will include
all embodiments falling within the scope of the appended
claims.
* * * * *