Note: Descriptions are shown in the official language in which they were submitted.
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WO 99/54040 PCT/US99/08338
CATALYTIC COMPOSITION COMPRISING A TrTANIUM COI~OUND, AN AMINE AND A
PHOSPHORUS COM-
POUND; PREPARATION AND USE TI~~REOF
FIELD OF INVENTION
This invention relates to a catalyst composition comprising a titanium
compound, to a process for producing the composition, and to a process for
using
the composition in, for example, esterification, transesterification, or
polymerization of a carbonyl compound.
BACKGROUND OF THE INVENTION
1o Polyesters such as, for example, polyethylene terephthalate (PET) and
polybutylene terephthalate (PBT), generally referred to as "polyalkylene
terephthalates", are a class of important industrial polymers. They are widely
used
in thermoplastic fibers, films, and molding applications.
Polyalkylene terephthalates can be produced by transesterification of a
15 dialkyl terephthalate ester with a glycol or by direct esterification of
terephthalic
acid with the selected glycol followed by polycondensation. A catalyst is used
to
catalyze the esterificarion, transesterification or polycondensation.
Many commercial processes use manganese or zinc salts as the catalyst for
the transesterification step. Antimony, in the form of a glycol solution of
antimony
20 oxide, typically is used as the polycondensation catalyst in either the
transesterification or direct esterification process outlined above. However,
antimony forms insoluble antimony complexes that plugs fiber spinnerets.
Furthermore, the use of antimony catalysts is generally less environmentally
fiiendly, especially in food contact applications.
Z5 ~ Organic titanates, such as tetraisopropyl and tetra n-butyl titanates,
are
lmown to be effective polycondensation catalysts for preparing polyalkylene
terephthalates in general, and fi-eQueatly are the catalyst of choice.
However,
organic titanates are not generally used in producing PET because residual
titanate
tends to react with trace impurities, such as aldehydes, formed during the
3o polycondensation and processing of PET thereby generating undesirable
yellow
discoloration Additionally, many organic titanate catalysts are also
substantially
insoluble in a polymerization mixture thereby creating non-uniform
distribution of
catalyst in the mixture.
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Therefore, there is an increasing need for the development of a new
catalyst that is substantially soluble, efficient, and produces a polymer with
reduced
color.
An advantage of the present invention catalyst composition is that, when
used in producing a particular polyalkylene tereFhthalate, it has a high
reactivity
and the polymer produced therefrom has improved optical properties (e.g., less
undesirable color) compared to polymer produced using previously known organic
titanate catalysts. Other advantages will become more apparent as the
invention is
more fully disclosed hereinbelow.
to SUMMARY OF THE INVENTION
According to a first embodiment of the present invention, a catalyst
composition, which can be used as an esterification or transesterification
catalyst,
or as a polycondensation catalyst to produce polyalkylene terephthalates, is
provided. The composition comprises an organic titanium compound, a
phosphorus compound, a tertiary amine, and optionally a cocatalyst.
According to a second embodiment of the present invention a process for
the production of a catalyst composition is provided. The process comprises
combining a solvent, an organic titanium compound, a phosphorus compound, a
tertiary amine, and optionally a cocataIyst.
2o According to a third embodiment of the present invention, a process which
can be used in, for example, the production of an ester or polyester is
provided.
The process comprises contacting, in the presence of a catalyst composition, a
carbonyl compound with an alcohol. The catalyst composition is the same as
that
disclosed above.
DETAILED DESCRIPTION OF THE INVENTION
According to the first embodiment of the present invention, a catalyst
composition
is provided. The composition can comprise an organic titaniurn compound, a
phosphorus compound, an amine, and optionally a cocatalyst. The composition
can
also consist essentially or consist of an organic titanium compound, a
phosphorus
3o compound, an amine, and a cocatalyst.
The catalyst composition of this invention is substantially soluble in a
solvent. The term "substantially" means more than trivial. It is preferred
that the
composition be completely soluble in the solvent. However, a substantial
portion
of the composition can also be suspended or dispersed in the solvent.
According to
the present invention the presently preferred titanium compounds are organic
2
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titanium compounds. Titanium tetrahydrocarbyloxides are presently the most
preferred organic titanium compounds because they are readily available and
effective. Examples of suitable titanium tetrahydrocarbyloxide compounds
include
those expressed by the general formula Ti(OR)a where each R is individually
selected from an alkyl, cycloalkyl, aralkyl, hydrocarbyl radical containing
from 1 to
about 30, preferably 2 to about I8, and most preferably 2 to I2 carbon atoms
per
radical and each R can be the same or different. Titanium
tetrahydrocarbyloxides
in which the hydrocarbyl group contains from 2 to about 12 carbon atoms per
radical which is a linear or branched alkyl radical are most preferred because
they
1o are relatively inexpensive, more readily available, and effective in
forming the
solution. Suitable titanium tetrahydrocarbyloxides include, but are not
limited to,
titanium tetraethoxide, titanium propoxide, titanium isopropoxide, titanium
tetra-n-
butoxide, titanium tetrahexoxide, titanium tetra 2-ethylhexoxide, titanium
tetraoctoxide, and combinations of any two or more thereof.
The presence of a halide, or of other active substituent, in the R group
generally is avoided since such substituents can interfere with catalytic
reactions or
form undesired by-products, which can contaminate the polymer when the
titanium
compound is used for producing a polymer. Presently it is also preferred that
the
each R group is identical to facilitate synthesis of the organic titanate. In
some
z0 cases two or more R groups can be from a common compound chemically bonded
together other than at the titanium atom (i.e., multidentate ligands such as
triethanolamine, citric acid, or lactic acid).
The titanium tetrahydrocarbyloxides suitable :for use in the present
invention can also be produced by, for example, mixing titanium tetrachloride
and
an alcohol in the presence of a base, such as ammonia, to form the tetraalkyl
titanate. The alcohol typically is ethanol, n-propanol., isopropanol, n-
butanol, or
isobutanol. Methanol generally is not employed because the resulting
tetramethyl
titanate is insoiuble in the reaction mixture, complicating its isolation.
Tetraalkyl
titanates thus produced can be recovered by first removing by-product ammonium
3o chloride by any means known to one skilled in the art such as filtration
followed by
distilling the tetraalkyl titanate from the reaction mixture. This process can
be
carried out at a temperature in the range of from about 0 to about
150°C.
Titanates having longer alkyl groups can also be produced by
transesterification of
those having R groups up to C4 with alcohols having more than 4 carbon atoms
per
molecule.
Examples of commercially available organic titanium compounds include,
but are not limited to, Tyzor~ TPT and Tyzor~ TB'1' (tetra isopropyl titanate
and
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tetra n-butyl titanate, respectively) available from E. I. du Pont de Nemours
and Company, ~Imington, Delaware, U.S.A.
The presently preferred phosphorus compound is an organic phosphorus
compound. The presently most preferred phosphorus compound has the formula
5 selected from the group consisting of (R~O)x(PO)(aH)3.x,
(Ri0)s.(OH)~.y(P~03),
and combinations thereof in which each R' is the same or diff~rc;nt and can be
selected from a linear or branched alkyl radical, or combinations of two or
more
thereof containing from 1 to about 20, preferably 1 to about 15, and most
preferably 1 to 10 carbon atoms per radical; x is 1 or 2; and y is 1, 2, or 3.
Each
1o radical can be substituted or unsubstituted. Each R' can also be
substituted with a
hydroxyl group. iVVishing not to be bound by theory, it appears that the
phosphorus compounds bind,to an organic titanium compound during preparation
of the catalyst composition thereby improving the solubility of the titanium
compound and aiding in control of the optical properties on the polyester
produced
15 usi.~g these compounds.
It is presently most preferred that Rl radical is unsubstituted alkyl radical
having up to 8 carbon atoms. However, the radical can also be substituted with
substituent groups) that do not unduly interfere with preparation of the
catalyst
composition or its subsequent use. Examples of suitable phosphorus compounds
2o include, but are not limited to, butyl phosphate, dibutyl phosphate, propyl
phosphate, dipropyl phosphate, ethyl pyrophosphate, diethyl pyrophosphate,
triethyl pyrophosphate, butyl pyrophosphate, dibutyl pyrophosphate, tributyl
pyrophosphate, octyl phosphate, dioctyl phosphate, nonyl phosphate,
dinonylphosphate, and combinations of two or more thereof. A mixture of butyl
25 and dibutyl phosphate, with butyl pyrophosphates, is particularly
preferred.
The organic phosphorus compounds are commercially available or can be
produced by the contacting of an alcohol with phosphorus oxide. For example, a
mixture of mono- and dibutyl phosphate and butyl pyrophosphates can be
produced by contacting phosphorus pentoxide with n-butanol.
3o According to the present invention. the amine is a tertiary having the
formula of (RZ)3N in which RZ is alkyl, alkoxyalkyl, hydroxyalkyl,
hydroxyaIkoxyalkyl, or combinations of two or more thereof. The presently most
preferred amine is a tertiary amine with one alkanol substituent. These amines
are
well known in the art and generally available commercially. Examples of
suitable
35 amines include, but are not limited to, 2[2-(dimethylamino)ethoxy]ethanol,
2-dimethyla.minoethanol, 2-diethyla.minoethanol, and tetra-
methylethylenediamine
4
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and combinations of two or more thereof.
Any solvent that can substantially dissolve the catalyst composition
disclosed above can be used in the present invention. The presently preferred
solvent is an alcohol having the formula of R3(OH)", an alkylene glycol of the
s formula (HO)~A(OH)", a polyalkylene glycol or alkoxylated alcohol having the
formula of R30[CHZCH(R3)O]"H, or combinations of two or more thereof in
which each R3 can be the same or different and is a hydrocarbyl radical having
1 to
about 10, preferably 1 to about 8, and most preferably 1 to 5 carbon atoms per
radical. The presently preferred R' is an alkyl radical, either branched or
straight
1o chai.~. A can have 2 to about 10, preferably 2 to about 7, and most
preferably 2 to
4 carbon atoms per molecule. Each n can be the same or di$'erent and is
independently a number in the range of from 1 about to about 10, preferably 1
to
about 7, and most preferably 1 to 5. Examples of suitable solvents include,
but are
not limited to, ethanol, propanol, isopropanol, butanol, ethylene glycol,
propylene
15 glycol, isopropylene glycol, butylene glycol, 1-methyl propylene glycol,
pentylene
glycol, diethylene glycol, triethylene glycol, 2-ethyl hexanol, and
combinations of
two or more thereof. The presently preferred solvent is ethylene glycol for
the
polyester produced therefrom has a wide range of industrial applications.
The catalyst composition can further comprise a cocatalyst. Examples of
2o cocatalysts include, but are not limited to, cobalt/aluminum catalysts ,
antimony
compounds, and combinations thereof. The cobaltJaluminum catalyst comprises a
cobalt salt and an aluminum compound in which the mole ratio of aluminum to
cobalt is in the range of from 0.25:1 to 16:1. The cobaltlaluminum catalyst is
disclosed in the U.S. patent number 5,674,801, disclosure of. which is
incorporated
25 herein by reference.
The presently preferred antimony compound can be any antimony
compounds that are substantially soluble in a solvent disclosed above.
Examples of
suitable antimony compounds include, but are not limited, antimony oxides,
antimony hydroxides, antimony halides, antimony sulfides, antimony
carboxylates,
3o antimony ethers, antimony glycolates, antimony alcoholates, antimony
nitrates,
antimony sulfates, antimony phosphates, and combinations of two or more
thereof.
According to the first embodiment of the present invention, the molar ratio
of phosphorus compound to titanium compound, measured as P:Ti, can be in the
range of from about 0.001:1 to about 1:1, preferably about 0.01:1 to about
1:1,
35 and most preferably 0.1:1 to 1:1. The molar ratio of amine to titanium
compound
can be in the range of from about0.001:1 to about l.: l, preferably about
0.01:1 to
about 1:1, and most preferably 0.1:1 to 1:1. The molar ratio of cocatalyst to
s
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WO 99/54040 PCT/US99/08338
titanium compound such as Sb:Ti or Co :Ti can be in the range of from about
0.01:1 to about 10:1. Presently it is preferred that the molar ratio of amine
to
phosphorus compound be about or less than 1:1. Alternatively, the titanium
compound can be present in the catalyst composition in the range of from about
0.01 to about 15, preferably about 0.1 to about 10, and most preferably 0.5 to
5
percent (%), based nn total weight of the composition as 100 %.
While the catalyst composition has been described in detail for its preferred
application, as a polycondensation catalyst for the manufacture of
polyalkylene
terephthalates, the composition also has general utility as an esterification
or
1o transesterification catalyst in conventional processes requiring a highly
active
catalyst. For example, the catalyst composition may be employed in the
reaction of
phthalic anhydride and octyl alcohol to from dioctyl phthalate, a plasticizer
for
polyvinyl chloride, having low haze. The relative ratios of the catalyst
components
can be adjusted to meet the requirements of a particular application.
is The catalyst composition can be produced by any means known to one
skilled in the art. FIowever, it is preferred it be produced by the process
disciosed
in the second embodiment of the present invention.
The catalyst composition can be produced in a solvent that is compatible
with or does not interfere with an esterification or transesterification or
2o polycondensation reaction. For example, if the catalyst composition is used
as a
polycondensation catalyst for producing PET, the composition is preferably
produced in ethylene glycol; if the catalyst composition is used for producing
PBT,
the composition is preferably produced in 1,4-butanediol; and if the catalyst
composition is used for producing polypropylene terephthalate PPT, the
25 composition is preferably produced in 1,3-propylene glycol. For the
production of
dioctylphthalate, 2-ethylhexyi alcohol is preferred.
While the individual components can be combined in any order, it is
preferred to first combine an amine and a solvent to produce a first mixture.
The
first mixture is then combined with a phosphorus compound to produce a second
3o mixture because an amine aids the phosphorus compound to dissolve.
Generally
the combination for producing the first or second mixture can be stirred and
can be
carried out at a temperature in the range of from about 0 °C to about
100°C,
preferably about 30°C to about 50°C. Generally any amount of
solvent can be
used as long as the amount can substantially dissolve the composition and can
be in
35 the range of from about 5 to about 50, preferably about 10 to about 30, and
most
preferably 10 to 20 moles per mole of the titanium compound used in the
composition.
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WO 99/54040 PCT/US99/08338
The titanium compound can then be combined with the second mixture to
produce the catalyst composition of the present invention. This step is
preferably
carried out under an inert atmosphere, such as nitrogen, carbon dioxide,
helium, or
combinations of two or more thereof to avoid liberating a flammable alcohol
because this step is exothermic causing the temperature to rise 10 to
30°C. This
step can be carried out by stirring for a period of time sufficient to
substantially
dissolve the titanium compound, generally about 5 minutes to about 20 hours or
more followed by cooling to ambient temperature.
Alternatively, the phosphorus compound can be combined with a solvent
and a titanium compound to form a complex. The complex can be isolated from
the solvent by any conventional means such as filtration to produce an
isolated
complex. The isolated complex can then be combined with a mixture which
comprises a solvent, an amine, or cocatalyst, or combinations of two or more
thereof to produce the catalyst composition of the present invention.
The quantities of individual components can vary with the selected
compounds and generally can be such that the molar ratio of each component to
titanium in the catalyst compound produced is within the range disclosed
above.
The structure of the catalyst system has not been established. Based on the
observed exotherm, however, it is believed that the components have reacted or
2o complexed in some manner to form binary or tertiary composition(s), at
least to
some extent, that render the catalyst composition especially useful as a
polycondensation catalyst in the manufacture of polyalkylene terephthalates in
general, and polyethylene terephthalate (PET) in particular.
According to the third embodiment of the present invention, a process
which can be used in, for example, the production of an ester or polyester is
provided. The process comprises contacting, in the presence of the catalyst
composition, a carbonyl compound with an alcohol. The catalyst composition is
the same as that disclosed above in the first embodiment of the present
invention.
According to the third embodiment of the invention, any carbonyl
3o compound which can react with an alcohol to produce an ester can be used.
Generally, such carbonyl compounds include, but are not limited to, acids,
esters,
amides, acid anhydrides, acid halides, oligomers or polymers having repeat
units
derived from an acid, or combinations of two or more thereof. The presently
preferred acid is an organic acid. The presently prefecTed processes are ( I )
the
production of an ester such as, for example, bis(2-ethylhexyl)phthalate from
phthalic anhydride and 2-ethylhexanol and (2) the polymerization of an acid or
an
z
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WO 99/54040 PCT/US99/08338
ester and an alcohol for the production of a polyester.
A preferred process for producing an ester or polyester comprises, consists
essentially of, or consists of contacting a reaction medium with a composition
disclosed above in the first embodiment of the invention. The reaction medium
can comprise, consist essentially of, or consist of (1) either an organic acid
or an
ester thereof and an alcohol, or (2) an alcohol and an oligomer having repeat
units
derived from an organic acid or ester.
The carbonyl compound can have the formula of (HO)",R°(COOR')p in
which m is a number from 0 to about 10, preferably 0 to about 5, and most
to preferably 0 to 3; each R° and R' can be independently (1) hydrogen,
(2)
hydrocarbyl radical having a carboxylic acid group at the terminus, (3)
hydrocarbyl
radical, or (4) combinations of, two or more thereof in which each radical can
be
substituted or unsubstituted; each radical has 1 to about 30, preferably about
3 to
about 15 carbon atoms per radical which can be alkyl, alkenyl, aryl, alkaryl,
aralkyl
radical, or combinations of two or more thereof; and p can be an integer from
1 to
a number equaling to the number of carbon atoms of R°. Any anhydrides
of the
organic acids can also be used. The presently preferred organic acid is an
organic
acid having the formula ofH02CA'COZH in which A' is an alkylene group, an
arylene group, alkenylene group, or combinations of two or more thereof. Each
2o A' has about 2 to about 30, preferably about 3 to about 25, more preferably
about
4 to about 20, and most preferably 4 to 15 carbon atoms per group. Examples of
suitable organic acids include, but are not limited to, terephthaIic acid,
isophthafic
acid, napthalic acid, succinic acid, adipic acid, phthalic acid, glutaric
acid, acrylic
acid, oxalic acid, benzoic acid, malefic acid, propenoic acid, 4-
hydroxybenzoic acid,
12-hydroxydecanoic acid, 6-hydroxyhexanoic acid, 4-hydroxycinnamic acid, 4-
hydroxymethylbenzoic acid, 4-hydroxyphenylacetic acid, azelaic acid, salicylic
acid,
caproic acid, stearic acid, palmitic acid, fumaric acid, naphthlane
dicarboxylic acid,
citric acid, trimesic acid, pamoic acid, sebacic acid, any anhydride of these
acids,
and combinations of two or more thereof. The presently preferred organic acid
is
3o terephthalic acid because the polyesters produced therefrom have a wide
range of
industrial applications. Examples of suitable esters include, but are not
limited to,
dimethyl adipate, dimethyl phthalate, dimethyl terephthalate, methyl benzoate,
dimethyl glutarate, and combinations of two or more thereof.
Any alcohol that can esterify an acid to produce an ester or polyester can
be used in the present invention. The presently preferred alcohol has the
formula of
Rs(OFl7~, an alkylene glycol of the formula (HO)"A(OFl7~, or combinations
thereof
in which each R' can be the same or different and is a hydrocarbyl radical
having 1
a
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a.
WO 99/54040 PCT/US99/08338
to about 20, preferably 1 to about 12, and most preferably I to 8 carbon atoms
per
radical. The presently preferred R' is an alkyl radical, either branched or
straight
chain. A can have 2 to about 10, preferably 2 to about 7, and most preferably
2 to
4 carbon atoms per molecule. Each n can be the same or different and is
independently a number in the range of from 1 about to about 10, preferably 1
to
about 7, and most preferably 1 to 5. Examples of suitable alcohols include,
but are
not limited to, ethanol, propanol, isopropanol, butanol, ethylene glycol,
propylene
glycol, isopropylene glycol, butyiene glycol, 1-methyl propylene glycol,
pentylene
glycol, diethylene glycol, triethylene glycol, 2-ethyl hexanol, stearyl
alcohol, 1,6-
1o hexanedioi, glycerol, pentaerythritol, and combinations of two or more
thereof.
The presently most preferred alcohol is an alkyiene glycol such as ethylene
glycol
for the polyester produced therefrom has a wide range of industrial
applications.
The contacting of reaction medium with the catalyst can be carried out by
any suitable means. For example, the individual compositions of the reaction
medium can be combined before being contacted with the catalyst. However, it
is
presently preferred that the catalyst be first dissolved or dispersed in an
alcohol by
any suitable means such as mechanical mixing or stirring to produce a solution
or
dispersion followed by combining the solution or dispersion with ( 1 ) an
organic
acid, an ester, an oligomer of an organic acid, or combinations of tvvo or
more
2o thereof and (2) an alcohol under a condition sufficient to effect the
production of
an ester or polyester.
The oligomer of the diacid and alkylene glycol generally has a total of
about 1 to about 100, preferably from about 2 to about 10 repeat units derived
from the diacid and alkylene oxide.
A suitable condition to effect the production of a polyester can include a
temperature in the range of from about 150°C to about 3 SO°C,
preferably about
200°C to about 300°C, and most preferably 250°C to
300°C under a pressure in
the range of from about 0.001 to about 10 atmospheres for a time period of
from
about 1 to about 20, preferably about 1 to about 15, and most preferably 1 to
10
hours.
The molar ratio of the alcohol (or alkylene glycol) to carbonyl compound
(or organic acid or ester thereof] can be any ratio so long as the ratio can
effect the
production of a polyester. Generally the ratio can be in the range of from
about
1:1 to about 10:1, preferably about 1:1 to about 5:1, and most preferably
about 1:1
to about 3: I . The molar ratio of the alcohol (or alkylene glycol) to
carbonyl
compound (or organic acid or ester thereof) for the oligomer having repeat
units
derived from the carbonyl compound (or organic acid or ester thereof) can be
q:(q-
9
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WO 99/54040 PCT/US99/08338
1) in which q can be a number in the range of from about 2 to about 100,
preferably about 2 to about 10 and most pa~eferably about 2 to about 5.
The catalyst can be present in the range of about 0.0001 to about 30,000
parts per million by weight (ppmw) of the polymerization medium, preferably
5 about 0.001 to about 1,000 ppmw, and most preferably 0.1 to about 100 ppmw.
Other ingredients also can be present to enhance catalyst stability or
performance.
While the advantages of the catalyst can be obtained with polyallrylene
terephthalates in general, the advantages are particularly evident as a
substitute for
most of antimony in the manufacture of PET since color purity is an important
to criteria for commercial articles typically made from PET.
The catalyst composition can be used in producing esters or polyesters by
using any of the conventional melt or solid state techniques. The catalyst
compositions are compatible with conventional esterification and
transesterification
catalysts (e.g., manganese, cobalt, and/or zinc salts) and may be introduced
to the
15 production process concurrent with, or following, introduction of the
esterification
catalyst. The catalyst compositions also have been found to be effective in
promoting the esterification reaction, and may be used as a substitute for
some or
all of the esterification catalyst as well as the polycondensation catalyst.
The following Examples are provided to further illustrate the present
2o invention and are not to be construed as to unduly limit the scope of the
invention.
EXAMPLES
DMT (dimethyl terephthalate) and TPA (terephthalic acid) oligomers were
made following Procedures A and B. The oligomers were blended with various
catalysts following Procedure C. Color of the polymer was measured as
described
25 in Procedure D.
PREPOLYMER PREP AND TESTING
A. ANTIMONY FREE DMT OLIGOMER
The oligomers used in these examples were prepared using dimethyl
terephthalate, ethylene glycol, zinc acetate, with no added antimony. It was
3o prepared as follows:
An autoclave was charged with 100 pounds of dimethyl terephthalate,
67 pounds of ethylene glycol and 4.4 gms of zinc acetate dihydrate. The batch
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was heated to 240°C at an agitation speed of 15 rpm, and 33 pounds of
methanol
and 14.3 pounds of ethylene glycol removed. The charge was then heated to
275°C over the course of 90 minutes, and the remaining ethylene glycol
removed
at 285°C and below 2 mm Hg vacuum. Once the condensation mass was
judged to
be complete, the molten mass was extruded into an aqueous bath to solidify the
product. The resultant polymer was dried to remove residual moisture before
use.
B. ANTIMONY FREE TPA OLIGOMER
When an oligomer was prepared from terephthalic acid (TPA) instead of
DMT, essentially the same procedure was used except for the omission of zinc
1o acetate catalyst
C. OLIGOMER/CATALYST BLENDS
A 1-liter resin kettle was provided with an Jiffy Mixer agitator rotating at
40 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle was added
the catalyst to be tested, 115 ml of ethylene glycol, and 400 gm of TPA
oligomer
prepared as in B. The agitator was turned on and the temperature was increased
to
275°C over a period of about 2.5 hours. The contents were polymerized
by
holding under agitation at 275°C and a pressure of 120 tore for 20
minutes, and at
280°C and a pressure of 30 tore for an additional 20 minutes. The
contents were
then held under agitation at 285°C at 1 to 2 mm Hg pressure for a time
sufficient
2o to reach 15 oz-in (ounce-inches) torque as measured by an Electro-Craft
Motomatic torque controller. The time for this step was recorded as the Finish
Time, and varied with the catalyst used. The polymer melt was then poured into
a
water bath to solidify the melt, and the resultant solid annealed at
150°C for
12 hours and ground to pass through a 2 mm filter for color measurements using
the previously described spectrophotometer. Results comparing the Finish Time
in
minutes and the Color as measured spectrophotometrically as described in D are
given in Tables 1 and 2.
D. COLOR MEASUREMENT
In the following examples, polymer color was measured in terms of the
3o L-value and b-value, using an instrument such as the SP-78
Spectrophotometer.
The L-value shows brightness, with the greater the numerical value showing
higher
(desirable) brightness. Preferably, the L-value will be equal to or higher
than that
of the polymer made using antimony catalyst. The b-value shows the degree of
m
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WO 99/54040 PCT/US99/08338
yellowness, with a higher numerical value showing a higher (undesirable)
degree of
yellowness. Preferably, the b-value will be equal to or lower than that of the
polymer made using antimony catalyst.
Control A To a 2,000-ml flask equipped with a water-cooled jacket, agitator,
s thermocouple, dropping funnel and a nitrogen sweep was added 900 gm of
tetraisopropyl titanate (3.2 mole). Then 576 gm of "ZELEC TY" acid phosphation
mass (3.2 mole) was added drop-wise with cooling keeping the temperature under
50°C. (ZELEC TY acid phosphation mass is nominaLy a 1:1 molar mixture
of
monobutyl and dibutyl phosphate esters, but r.naiyses indicate it also
contains some
to amount of the corresponding pyrophosphate esters. It is available from E.
I.
du Pont de Nemours and Corripany). The catalyst is a liquid and can be used as
such. When this catalyst, with no amine, is placed in ethylene glycol, a
suspension
is formed. This must be mixed before use to get a uniform mixture.
Ezamr~le 1 A 250 ml flask equipped with a water-cooled condenser, agitator,
15 thermocouple, dropping funnel and a nitrogen sweep, was charged with 33 gm
(0.116 moles) of tetra-isopropyl titanate (TYZOR TPT) and 23 gm of isopropyl
alcohol. Agitation was started and 21 gm (0.116 moles) of ZELEC TY acid
phosphation mass was added dropwise over 10 minutes. The reaction mass was
heated to 60C and held 1 hr. after which 15.5 gm (0.116 moles) of 2[2-
20 (dimethylamino)ethoxy]ethanol was added dropwise. The reaction mass was
held
2 hr. at 60C and then bottled out. The resultant pale yellow liquid contained
5.99% of Ti and was glycol-soluble.
Control B A 250 ml flask equipped as in example 1 was charged with 50 gm
(0.176 moles) of tetra-isopropyl titanate (Tyzor~ TPT) and 34.8 gm of
isopropyl
25 alcohol. Agitation was started and 30.69 gm (0.176 moles) of a mixed butyl
phosphate ester obtained from Albright and Wilson was added dropwise. This
mixture of mono- and di-butyl phosphate ester has no pyrophosphate present.
The
solution was heated to 60°C and held for 2 hrs., then 23.42 gm (0. I76
moles) of
2(2-(dimethylamino)ethoxy]ethanol was added dropwise and the reaction mass
3o stirred at 60°C for another 4 hr. The product was a pale yellow
solution
containing 6.06% Ti. and was glycol-soluble.
In Table I, the Ti component was tetraisopropyl titanate, the P component
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WO 99/54040 PCT/US99/08338
was a mixed butyl phosphate ester and the A component was dimethylamino
ethoxy ethanol (DMAEE). 'The amount of titanium was 25 parts per million
(ppm) by weight of starting oligomer. The finish time is the time on hold at 2
mm
Hg pressure to achieve the goal viscosity. These runs were carried out with
TPA
oIigomer of Procedure B. All catalysts are glycol-soluble except where so
noted.
Table 1
Comparison of Catalysts for Finish Time and Color
TPA based oligomer. 2tnm H .g 285C, 25ppm Ti
Mole Col or
Ratio
Example Other Finish
No. Ti P A~ ComponentTune L b Notes
(min.)
0.0 0.00.0 Antimony 220 72.145.121
Control1.0 1.00.0 None 140 74.453.442,3
A
1 1.0 1.01.0 DMAEE 120 76.855.512
Control1.0 1.01.0 DMAEE 210 77.178.264
B
Notes: 1. This is a Control Run using 300 ppm antimony catalyst shown for
comparison.
2. This catalyst was prepared using 7FT.FC TY mixed butyl phosphate as the
phosphate ester.
3. This catalyst did not contain the A component and was ethylene glycol
insoluble.
4. This catalyst was prepared using Albright and Wilson mixture of mono- and
di-butyl
phosphate ester, with no measurable amount of pyrophosphate present
Table 1 illustrates that the use of a phosphate ester mixture containing
significant amounts of pyrophosphate (Example 1 ) has a significantly faster
condensation rate than if a mixture containing only mono- and diester was used
(Control B). Control A was insoluble in ethylene glycol, undesirable for
commercial use. In addition to the shorter condensation time obtained with the
mixture containing pyrophosphates, this run also demonstrated an improved
2o polymer color.
In the following series of examples, various tertiary amines were used as
solubilizing agent. The Ti-P-A catalysts of this invention were then tested as
in
Table 1, except that a DMT based oligomer was used for the test and the finish
pressure was changed from 2mm Hg to 1 mm Hg. Results are given in Table 2.
Example 2 Titanate-phosphate ester-amine catalyst mixture was prepared as
follows. To a 500-ml flask equipped with a water-cooled jacket, agitator,
thermocouple, dropping funnel and a nitrogen sweep was added 176 gm of
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WO 99/54040 PCT/US99/08338
tetraisopropyl titanate (0.6 mole) Tyzor~ TPT. Then 56 gm of "Zelec" TY acid
phosphation mass (0.3 mole) was added drop-wise with cooling keeping the
temperature near 40°C.
To 13.2 gm of the above material (0.03 5 mole of titanate and 0.018 mole
s of acid phosphate) was added 1.85 gm (0.0I 8 mole) of diethanolamine at
ambient
temperature.
Ezamnle 3 A 100 ml flask equipped with an ag;tator, thermometer, nitrogen
inlet and condenser was charged with 15 gm( 0.053 moles) of tetra-isopropyl
titanate (Tyzor~ TPT from E. I. du Pont de Nemours and Company). Agitation
1o was started and 4.8 gm (0.026 moles) of a mixed butyl phosphate ester was
added
dropwise over 10 minutes (ZELEC TY acid phosphation mass). T he reaction
mass was then neutralized with 3.09 gm (0.05 moles) oft[2-
(dimethylamino)ethoxy]ethanol. The reaction mass was then diluted with 16.37
gm of ethylene glycol, to give a clear, pale yellow solution containing 6.44%
Ti,
15 which was soluble in ethylene glycol at the 5% level.
Ezamule 4 A 100 ml flask equipped as in Example 3 was charged with 30 gm
(0.106 moles) of tetra-isopropyl titanate (Tyzor~ TPT). Agitation was started
and
9.6 gm(0.053 moles) of a mixed butyl phosphate ester (ZELEC TY acid
phosphation mass) was added dropwise over 10 minutes. The reaction mass was
2o neutralized with 6.13 gm (0.053 moles) of tetramethylethylenediamine to
give a
clear, pale yellow solution containing 11.1% Ti, which was soluble in ethylene
glycol at the 5% level.
Ezampie 5 To a 250 ml flask, equipped as in Example 3 was charged 50 gm
(0.176 moles) of tetra-isopropyl titanate (Tyzor~ TPT) and 35 gm of isopropyl
25 alcohol. Agitation was started and 16 gm (0.088 moles) of a mixed butyl
phosphate ester (ZELEC TY acid phosphation mass) was added dropwise over 10
minutes. The reaction mass was heated to 60C and held for 1 hr. after which 1
I.7
gm (U.088 moles) of 2[2-(dimethylamino)ethoxy]ethanol was added dropwise and
agitation continued for 2 hr. at 60C. The resultant pale yellow solution
contained
30 7.46% Ti and was ethylene glycol soluble at the 3% level.
Control C
To a 500 ml flask equipped as in Control B was charged 300 gm
( 1.055 moles) of tetra-isopropyl titanate (Tyzor~ TPT). Agitation was started
and
96 gm (0.528 moles) of a mixed butyl phosphate ester (ZELEC TY acid
35 phosphation mass) was added dropwise. The reaction mass was agitated
another
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30 minutes at room temperature to give a clear, pale yellow solution
containing
12.76% Ti. This material was not glycol soluble at the 5% level.
Table 2
Comparison of Catalysts for Finishing Time and Color
DMT Based Oligomer. lmm Hg, 285C. 25ppm Ti
Mole Co lor
Ratio
Example Other Finish
No. Ti P A ComponentTime L b Notes
(min.)
- 0.0 0.00.0 Antimony 65 72.606.17 1
2 1.0 0.50.5 DEA 80 71.3310.852
3 1.0 0.50.5 DMEAE 60 72.479.73 3
4 1.0 0.50.5.TM~A 67 70.2111.184
5 1.0 0.50.5 DMAEE 60 74.988.80 5
Control1.0 0.50 62 76.650.44 ~
C 6
Notes: 1. This is a control run of aatimony run at 260ppm, shown for
comparison.
2. DEA is diethanolamine.
3. DEAF is 2~iethylaminoethanol.
4. TMEDA is tttramethylethylenediamine.
5. DMAEE is 2[2-(dimethylaminokthoxy]ethanol.
6. This is a comparison example (Control C) where an amine was not added to
impart glycol
solubility.
Table 2 illustrates that the addition of tertiary amines to impart glycol
solubility enables glycol solubility without harming the condensation rates of
the
catalysts.
In the following series of examples, various combinations of antimony
catalyst were tested with the tetraisopropyl titanate/mixed butyl phosphate
ester/DMAEE catalyst of Example 5. These were then tested as in Table 1,
except
that a DMT based oligomer was used for the test. For greater accuracy in these
2o comparative runs, the intrinsic viscosity (LV.) of the resulting polymer
was
determined and the measured finishing time was corrected to a constant
intrinsic
viscosity of 0.66. The amount of titanium and antimony catalyst was varied as
shown in Table 3.
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WO 99/54040 PCT/US99/08338
Table 3
Comparison of Antimony Catalysts for Finishing Time and Color
DMT Based Oligomer 2mm Hst ,
Mole Color
Ratio
Catalyst
Example ppm MetalFinish
N~ T' P A Ti 8b Time (min.)L b Notes
_ Meal.
Corn.
Control 0 0 0 0 280 97 98 - - 1,2
D
6 1 0.5 0.5 3 280 87 87 - _ 2,3
7 1 0.5 0.5 6 140 86 76 - - 2,3
Control 0 0 0 0 375 98 92 70.5 -4.0 1
E
8 1 0.5 0.~ 20 100 80 77.5 75.0 3.3 3
Notes: 1. This is a conh~ot run with antimony, shown for comparison.
2. The color of product was not measured.
3. This run tested a combination of antimony with the composition of Example
S.
The above runs show a significant reduction in finishing time obtained by
using antimony in combination with the titanium/phosphate/amine composition of
15 Example 5, corresponding to an increase in productivity of nearly 20%. In
addition, in Example 8 the amount of antimony in the product was cut to nearly
one quarter the control amount, and the color of the product, as shown by
comparison with Tables 1 and 2, remained satisfactory.
16
