Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02368684 2001-12-21
Mo6829
PS-1086
ESBO ENHANCED HYDROGENATION
FIELD OF INVENTION
The present invention relates to a process of hydrogenating a
nitrite-diene copolymer rubber.
BACKGROUND OF THE INVENTION
Nitrite rubbers obtained by the emulsion copolymerization of
(meth)acrylonitrile with conjugated dienes, for example, butadiene, and
optionally.small amounts of other comonomers are known, for example,
from German Pat. No. 658,172. In addition, it is known ftom U.S. Patent
No. 3,700,637 that nitrite rubbers of this type can be hydrogenated, the
strength of the products thus obtained being improved, compared with the
non-hydrogenated starting material.
According to German published Patent Application No. 25 39 132,
the hydrogenation of statistical acrylonitrile butadiene copolymers in
solution also gives products having improved properties. In this case, the
reaction is selective with respect to the extent of hydrogenation.
SUMMARY OF THE INVENTION
It has now been found that metal-complex catalyzed hydrogenation
of a nitrite-diene copolymer rubber, in the presence of a cocatalyst, can be
accelerated by the addition of a small amount of a proton acceptor that is
non-coordinating with the metal-complex catalyst. In addition, it has also
been found that the amount of co-catalyst used can be lowered in the
presence of the proton acceptor.
Accordingly, the present invention provides a process of
hydrogenating a nitrite copolymer rubber, which comprises subjecting the
copolymer to hydrogenation in the presence of a hydrogenation catalyst, a
co-catalyst, and a proton acceptor that is non-coordinating with the metal-
complex catalyst.
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BRIEF DESCRIPTION QF 'SHE DR~QWING
Figure 1 shows a graph of the average percent hydrogenation of
Krynac~ X7.40 vs. time, as a fun~tibi~ o~ the aiiliount of added ESBO.
DETAILED DESCRIPTION OF THE INVENTION
The non-coordinating proton acceptor is to be understood generally as any
compound, which will accept a proton through protonation of a basic
moiety. The proton acceptor should not coordinate with the metal of the
hydrogenation catalyst. Some proton acceptors may coordinate with the
metal-complex catalyst. This coordination is not desirable. Proton
acceptors that have a significant adverse effect on the hydrogenation
reaction should be avoided.
The non-coordinating proton acceptor may be a mono-, di-, or
triacylglycerol comprising epoxide moieties, preferably a triacylglycerol
comprising epoxide moieties.
More specifically, the non-coordinating proton acceptor may be a
molecule of formula (1):
OR'
OR2 ( I )
OR3
where R', R2, and R3 are, independently of each other, hydrogen or a
group of formula (1l):
0 0
(II)
n x
where n = 1 to 7,
x = 1 to 3, and
m=1to6.
wherein at least one of R', R2 or R3 is other than hydrogen.
A specific example of such a non-coordinating proton acceptor is
selected from the group of epoxidized soy bean oil (ESBO), epoxidized
linseed oil, epoxidized corn oil, epoxidized coconut oil; epoxidized
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Mofi829 -3-
cottonseed oil, epoxidized olive oil, epoxidized palm oil, epoxidized palm
kernel oil, epoxidized peanut oil, epoxidized cod liver oif, epoxidized tung
oil, epoxidized beef tallow, and epoxidized butter, and a mixture of two or
more of the above compounds.
Epoxidized peanut oil, epoxidized cottonseed oil, epoxidized com
oil, epoxidized soybean oil, epoxidized olive oil, epoxidized linseed oil, and
epoxidized tung oil are preferably used as non-coordinating proton
acceptors.
The non-coordinating proton acceptor is more preferably epoxidized
soy bean oil (ESBO).
These epoxidized compounds are formed from the corresponding oils and
fats, using standard methods known in the art for converting unsaturated
compounds into epoxides.
Table 1 provides a list of these corresponding fats and oils, showing
the percentages of the constituent fatty acids in each fat or oil.
CA 02368684 2001-12-21
Mo6829' q;_
~O N
C O
~ b
N ~1 CIO
.
O ~ L~j
c N M N r N l0 p N r
= ~ M ~ N e~ I~.
d' N r' r ~, p p
0
a
O
~ N
...~. ao c- N
ti M N !..~y r M M c,
n 0 t~0 O' O N O V N
c
.O lV O O r to N pp ~p ,,~ r O M U
V ~ OO n r' (~ M t'M
N M V N r
~ ' ttjd0.~ M N N ~) d'
c'~~ N tt7M ~- N r- N
U' N N e- N '' a ~" O ~
,
V y N N, (p
V O ~ 0 O
e-
A , , N O M ~ U
O O O
r L~ r p
N ch ~ ~ N
~ M M to c'~ N O ~ v..
U r r N , U
N 0 r r !-r v-- .p U
~ ~
C \ ~ M M O O N M O ~
~ ~ r r p 'L
" j N N 1~.prep~ ~f7tV ~~- U
7 N h. M (O (p h:. h.~ U
(
~ N
O .~ U N M e- - p ~ O M p N ~ U
O ~ ~ eM-' v = ~ r
l O 0 N O ~ ~
t~
~ ~
N
t/3 .~ N
N ' e_ N c
U n o ~ U r
o ~ ~ ~ v;
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vi
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Q U N ~ 1 ~ co .U
e l. m tn
' .U
U ui
. V
.
U .D ~j
~- ( j N p' ~' N
r fj N r U f U
t I~ .'
f~
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y a
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a~
v~
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a ca ~ >_ a c ; ~ ~ a v
U U U o ~.a cc c v
~ O ,~ ~o
a
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The non-coordinating proton acceptor may also be an ester
comprising epoxide moieties. Such an ester may be an ester of a fatty
acid comprising epoxide moieties of formula (ill):
° °
R40 m (l11)
n x
or an ester of an alcohol comprising epoxide moieties of formula (IV):
o
R ~O n x
O
(IV)
1~
where, in each formula n = 1 to 7
x=1 to3,
m = 1 to 6, and
R4 is a hydrocarbyl group, for example, a C,-Cs alkyl group.
The non-coordinating proton acceptor may also be an amide comprising
epoxide moieties. Such an amide may be an amide of a fatty acid
comprising epoxide moieties of formula (V):
° (V)
ReRSN . n
or an amide of an amine comprising epoxide moieties of formula (VI):
R5 O
Re N
n x m
O
(VI)
wheren=lto7,
x = 1 to 3,
m = 1 to 6, and
R5 and R6 are chosen, independently of each other, from hydrogen,
and a hydrocarbyl group, e.g. a C~-Cs alkyl group.
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The non-coordinating proton acceptor may suitably be used in the
range of from 0.3 to 20 parts by weight per hundred parts by weight of
copolymer, preferably 0:5 to 10 parts by weight per hundred parts by
weight of copolymer, most preferably 0.5 to 5 parts by weight, per hundred
parts by weight of copolymer.
Many conjugated dienes are used in copolymer rubbers and all can
be used in the process of the present invention. Mention is made of 1,3-
butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and
piperylene, of which 1,3-butadiene is preferred.
The nitrite is normally acrylonitrile or methacrylonitrile, of which
acrylonitrile is preferred.
The copolymer that undergoes hydrogenation in the present
invention may comprise from 95 to 50°!° by weight, preferably 70
to 60%
by weight of conjugated diene, and from 5 to 50% by weight, preferably 30
to 40% by weight of an unsaturated nitrite. The copolymer may also
contain up to about 45%, preferably up to 40%, more preferably up to
10%, of one or more copotymerizable monomers, for example, an ester of
an unsaturated acid, such as ethyl, propyl or butyl acrylate or
methacrylate, or a vinyl compound, for example, styrene, a-methylstyrene
or a corresponding compound bearing an alkyl substituent on the phenyl
ring, for instance, a p-alkylstyrene such as p-methylstyrene. Other
copolymerizable monomers include a,~3-unsaturated acids, for example,
acrylic, methacrylic, ethacrylic, crotonic, malefic (possibly in the form of
its
anhydride), fumaric or itaconic acid, and other conjugated dienes, for
example 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, isoprene, and
piperylene. Preferably, the copolymer is a solid that has a molecular
weight in excess of about 60,000, most preferably in excess of about
100,000. There is effectively no upper limit on the molecular weight of the
copolymer, however, the molecular weight of the copolymer will usually not
exceed 1,000,000.
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The copolymer that is to be hydrogenated can be made in known
manner, by emulsion or solution polymerization, resulting in a statistical
copolymer. The copolymer will have a backbone compos~d entirely of
carbon atoms. It will have some vinyl side-chains, caused by 1,2-addition
of the conjugated diene during the copolymerization. It will also have
double bonds in the backbone from 1;4-addition of the diene. Some of
these double bonds will be in the cis and most in the trans orientation.
These carbon-carbon double bonds are selectively hydrogenated by the
process of the present invention, without concomitant hydrogenation of the
nitrite groups present in the copolymer. If carboxyl groups (from an a,~i-
unsaturated acid) are present, it is desired that these should not undergo
hydrogenation.
Processes for the hydrogenation of NBR are known and may also
be used for the production of the hydrogenation products according to the
present invention. A complex of rhodium or palladium, is generally used
as the catalyst, although platinum, iridium, rhenium, ruthenium, osmium,
cobalt or copper in the form of the metals, but preferably in the form of
metal compounds, may also be used, cf. for example U.S.Patent No.
3,700,637; DE-PS 2,539,132; EP 134 023; DE-OS 35 41 689; DE-OS 35
40 918; EP-A 298 386; DE-OS 35 29 252; DE-OS 34 33 392; U.S. Patent
No. 4,464,515; and U.S. Patent No. 4,503,196, all of which are
incorporated herein by reference.
Suitable catalysts and solvents for hydrogenation in the
homogeneous phase are described in the following, and in GB 1558491 of
Bayer AG and in EP 471,250, incorporated herein by reference. It is not
intended to restrict the catalysts and solvents for hydrogenation useful for
the invention, and these are provided only by way of example.
The hydrogenation can be achieved by means of a rhodium-complex
catalyst. The preferred catalyst is of the formula (VII):
(RmB~RhXn (VII)
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in which each R is a C~-C8-alkyl group, a C4-C8-cycloalkyl group a Cs C~5
aryl group or a C7 C~5 aralkyl group; B is phosphorus, arsenic, sulfur, or a
sulfoxide group S=0; X is hydrogen or an anion, preferably a halide and
more preferably a chloride or bromide ion; I is 2, 3 or 4, preferably 3; m is
2
or 3; and n is 1, 2 or 3, preferably 1 or 3. Preferred catalysts are tris-
(triphenylphosphine)-rhodium(I)-chloride, tris(triphenylphosphine)-
rhodium(lll)-chloride and tris-(dimethylsulfoxide)-rhodium(ll1)-chloride, and
tetrakis- (triphenylphosphine)-rhodium hydride of formula ((C6H5)3P)4RhH,
and the corresponding compounds in which triphenylphosphine moieties
are replaced by tricyciohexylphosphine moieties. The catalyst can be
used in small quantities. An amount in the range of 0.01 to 1.0%,
preferably 0.02% to 0.6%,more preferably 0.03 to 0.2%, most preferably
0.06 to 0.12% by weight based on the weight of copolymer is suitable.
The catalyst is used with a co-catalyst that is a ligand of formula
R,nB, where R, m and B are as defined above, and m is preferably 3.
Preferably B is phosphorus, and the R groups can be the same or
different. Thus, there can be used a triaryl, trialkyl, tricycloalkyl, diaryl
monoalkyl, dialkyl monoaryl, diaryl monocycloalkyl, dialkyl monocycloalkyl,
dicycloalkyl monoaryi or dicycloaikyl monoaryl co-catalysts. Examples of
co-catalyst ligands are given in US Patent No. 4,631,315, the disclosure of
which is incorporated by reference. Examples of co-catalyst ligands given
in US Patent No 4,631,315 include triphenylphosphine,
diethylphenylphosphine, tritolyiphosphine, trinaphthylphosphine,
diphenylmethylphosphine, diphenylbutyiphosphine, tris-(p-
carbomethoxyphenyl)-phosphine, tris-(p-cyanophenyl)-phosphine,
tributylphosphine, tris-(trimethoxyphenyl)-phosphines, bis-
(trimethylphenyl)-phenyl-phosphines, bis-(trimethoxyphenyl)-
phenylphosphines, trimethylphenyldiphenylphosphines,
trimethoxyphenyldiphenyl-phosphines, tris-(dimethyiphenyl)-
phenylphosphines, tris-(dimethoxyphenyl)-phosphines, bis-
(dimethylphenyl)-phenyl-phosphines, bis-(dimethoxyphenyl)-
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phenyiphosphines, dimethylphenyldiphenylphosphines,
dimethoxyphenyldiphenyiphosphines, triphenylarsine, ditolyiphenylarsine,
tris-(4-ethoxyphenyl)-arsine, diphenylcyclohexylarsine, dibutylphenylarsine
and diethylphenylarsine are preferred ligands.
Further examples of co-catalyst ligands are bisphosphines
corresponding to the formula (Vlll):
R' R9
\P (CHZr---P\/ (VI I f )
Ra ~R~ o
in which m represents an integer from 1 to 10 and the groups R', R8, R9,
R'° which may be the same or different represent alkyl, cycioaikyl,
aryl, or
aralkyl radicals, these groups optionally being substituted by alkyl,
hydroxy, alkoxy, carbalkoxy or halogen groups.
Other examples of co-catalyst ligands are compounds corresponding to
the formula (!X):
~Rt2
Cp (CHz?4-P (CHZr--P/\ (IX)
» R~3
Cp: Cyclopentadienyl
wherein q and r which may be the same or different represent an integer
from 1 to 6 and the radicals R~,, R,Z and R~3 which may be the same or
different have the same meaning as RrR,°.
Examples of such iigands are 1,4-diphospha-6-cyclopentadienyl-
1,1,4-triphenyihexane, preferably 1,5-diphospha-7-cyclopentadienyl-1,1,5-
triphenylheptane and, in particular, 1,6-diphospha-8-cyciopentadienyl-
1,1,6-triphenyloctane.
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The preferred co-catalyst ligand is triphenylphosphine. The co-
catalyst ligand is suitably used in an amount in the range of from 0.1 to
33% more 0.2 to 20%, preferably 0.3 to 5%, more preferably 0.5 to 4%,
based on the weight of the copolymer. Preferably, the weight ratio of the
catalyst compound to co-catalyst is in the range 1:3 to 1:66, preferably in
the range 1:5 to 1:45.
Triphenylphosphine is difficult to separate from the hydrogenated
copolymer product, and if it is present in any significant quantity may
create some difficulties in processing of the hydrogenated product. The
use of a non-coordinating proton acceptor lowers the amount of
tr~phenylphosphine cocatalyst needed in the hydrogenation reaction,
without lowering the efficiency of the reaction. In addition, It is not
necessary to remove an ESBO-like proton acceptor from the final
copolymer as it has the additional beneficial property of acting as a
plasticizer. Use of a proton acceptor in place of part of the co-catalyst,
therefore, gives rise to significant and unexpected advantages.
The hydrogenation reaction can be carried out in solution. The
solvent must be one that will dissolve the copolymer. This limitation
excludes use of unsubstituted aliphatic hydrocarbons. Suitable organic
solvents are aromatic compounds including halogenated aryl compounds
of 6 to 12 carbon atoms. The preferred halogen is chlorine and the
preferred solvent is a chlorobenzene, especially monochlorobenzene
(MCB). Other solvents that can be used include toluene, halogenated
aliphatic compounds, especially chlorinated aliphatic compounds, ketones
such as methyl ethyl ketone and methyl isobutyl ketone, tetrahydrofuran
and dimethylformamide. The concentration of copolymer in the solvent is
not particularly critical but is suitably in the range from 1 to 20% by
weight,
preferably from 2.5 to 15% by weight and more preferably 10 to 15% by
weight. The concentration of the solution may depend upon the molecular
weight of the copolymer rubber that is to be hydrogenated. Rubbers of
higher molecular weight are more difficult to dissolve, and so are used at
lower concentration.
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The reaction can be carried out in a wide range of pressures, from
to 250 atm. and preferably from 50 to 100 atm. The temperature range
can also be wide. Temperatures from 40 to 160°, preferably 100 to
160°C,
are suitable and from 110 to 140°C are preferred. Under these
conditions,
5 the hydrogenation is usually completed in about 3 to 7 hours, although
longer or shorter reaction times can be used if required. Preferably, the
reaction is carried out, with agitation; in an autoclave.
To extract the copolymer from the hydrogenation mixture, the
mixture can be worked up by any suitable method. One method is to distill
10 off the solvent. Another method is to inject steam, followed by drying the
copolymer. Another method is to add an alcohol, to cause the copolymer
to coagulate.
The copolymer of the present invention can be compounded with
any of the usual compounding agents, for example fillers such as carbon
black or silica, heat stabilizers, antioxidants, activators such as zinc oxide
or zinc peroxide, curing agents, co-agents, processing oils and extenders.
Such compounds and co-agents are known to persons skilled in the art.
The invention is further illustrated in the following non-limiting
examples and the accompanying drawing, of which:
Figure 1 is a graph of the average percent hydrogenation of
KrynacO X7.40 vs. time, as a function of the amount of added ESBO.
Example 1 illustrates hydrogenation of a carboxylated acrylonitrile-
butadiene rubber, Krynac~ X7.40 (available from Bayer) without the
addition of a proton acceptor. Example 2 illustrates the hydrogenation of
Krynac~ X7.40 in the presence of ESBO as proton acceptor.
Example 1
In an experiment with a 6% copolymer load, 184 g of Krynac~ X7.40 {a
statistical terpolymer of methacryiic acid (7%)-acrylonitrile (28%)-
butadiene (65%), ML 1+4/100°C = 40) was dissolved in 2.7 kg of
monochlorobenzene. The copolymer solution was transferred to a 2
gallon Parr high pressure reactor and nitrogenlargon was then passed
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through the copolymer solution for 10 minutes. The reactor was then
degassed 3 times with pure H2 (100-200 psi) under full agitation. The
temperature of the reactor was raised to 130°C and a solution of 0:139
g
(0.076 phr) of tris-(triphenylphosphine)-rhodium-(I)chloride and 2.2 g of
triphenytphosphine in 60 mL of monochlorobenzene was then charged to
the reactor under hydrogen. The temperature was raised to 138°C and the
pressure of the reactor was set at 1200 psi. The reaction temperature and
hydrogen pressures of the reactor were maintained constant throughout
the whole reaction. The degree of hydrogenation was monitored by
sampling after a certain reaction time followed by FTIR analysis of the
sample. The hydrogenation was carried out for a certain period of time at
138°C under a hydrogen pressure of 1200 psi. The monochlorobenzene
was removed by the injection of steam and the copolymer was dried in an
oven at 80°C. The values of % hydrogenation (% hyd.) were determined
by IR spectroscopy and'H-NMR. Table 2 gives the values of °!°
hydrogenation (% hyd.) as a function of time for three separate runs, as
well as the average values of % hydrogenation determined as a function of
time for all three runs. The average values of % hydrogenation are plotted
as a function of time in Figure 1.
Table 2. Hydrogenation of Krynac~ X7.40 in the Absence of ESBO.
Run 1 Run 2 Run 3 Average
Time (min) % hyd. % hyd. % hyd. % hyd.
0 0 0 0 0
60 77.5 64.9 66.4 69.6
120 83.2 74.8 76.7 78.2
180 85 81.5 83.7 83.4
240 85 83 83.7 83.9
Copolymer Load: 6%; Catalyst Load: 0.076 phr; Co-catalyst Load: 1.26
phr.
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Exam~a~
Hydrogenation reactions were carried out as in Example 1, except that 2
or 7 phr of ESBO was added to the copolymer cement before the
copolymer hydrogenation. Table 3 gives the values of % hydrogenation
(% hyd., as determined by iR spectroscopy and'H-NMR) as a function of
time for two different groups of runs; each group of runs was conducted
with a different amount of ESBO added (2 or 7 phr ESBO). The average
values of % hydrogenation determined as a function of time from the two
runs of each group are also shown. These average values of
hydrogenation were plotted as a function of time in Figure 1.
Table_3. Hydrogenation of KrynacO X7.40 in the Presence of ESBO.
2 phr 7 phr
ESBO ESBO
Run 1 Run 2 Average Run 1 Run 2 Average
Time % hyd. /~ hyd. % hyd. % hyd. % hyct. % hyd.
(min)
0 0 0 0 0 0 0
60 82.6 81.5 82.0 86.2 71.8 79
120 87.8 88.0 87.9 92.3 83.4 87.8
180 89.4 89.5 89.4 93.6 90.2 91.9
i 240 90.2 90.3 90.2 94.1 92.6 93.4
~
Copolymer load: 6%; Catalyst Load: 0.076; Co-catalyst Load: 1.26 phr.
It is evident that the presence of ESBO accelerated the rate of
hydrogenation of Krynac~ X7.40. In the cases where no ESBO was
added, less than 85% hydrogenation was achieved. With 2 phr ESBO
greater than 85% hydrogenation was achieved.
Examples 3 and 4 show the hydrogenation of an acrylonitrile-
butadiene copolymer, Perbunan~ NT 3429T (available from Bayer),
without and with the addition of ESBO, respectively.
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Example 3
In an experiment with a 12°/° copolymer load, 392 g of
Perbunan~
NT 3429T (statistical copolymer of acrylonitrile (34°/°)-
butadiene (66°l°),
Mooney ML 1+4 = 30) was dissolved in 2.6 kg of monochlorobenzene.
The copolymer iution was transferred to a 2 gallon Parr high pressure
reactor and nitrogenlargon was then passed through the copolymer
solution for 10 minutes. The reactor was then degassed 3 times with pure
HZ (100-200 psi) under full agitation. The temperature of the reactor was
raised to 130°C and a solution of 0.176 g (0.045 phr) of tris-
(triphenyiphosphine)rhodium (1 ) chloride catalyst and 3.92 g of co-catalyst
triphenylphosphine in 60 mL of monochlorobenzene was then charged to
the reactor under hydrogen. The temperature was then raised to 138°C
and the pressure of the reactor was set at 1200 psi. The reaction
temperature and hydrogen pressure of the reactor were maintained
constant throughout the reaction. The degree of hydrogenation was
monitored by sampling after a certain reaction time followed by FTIR
analysis of the sample. The hydrogenation was carried out after a certain
period of time at 138°C under a hydrogen pressure of 1200 psi. The
chlorobenzene was removed by the injection of steam and the copolymer
was dried in an oven at 80°C. The hydrogenation results (as determined
by IR spectroscopy and'H-NMR) of two runs are given in Table 4.
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Table 4. Hydrogenation of Perbunan~ NT 3429T in the Presence of 1
phr Triphenylphosphine.
Run 1 Run 2
Time 9~ hyd. % hyd.
(min)
0 0 0
60 90.6 87.2
120 96.9 96.7
180 98:4 98.7
240 98.9 99.2
Copolymer Load: 12%; Catalyst load: 0.045 phr; Co-catalyst Load: 1 phr.
Example 4
A hydrogenation reaction was carried out as in Example 3, except
that 2.0 phr of ESBO was added to the copolymer cement before the
hydrogenation. The hydrogenation results are summarized in Table 5.
Table 5. Hydrogenation of Perbunan~ NT 3429T in the presence of 1
phr triphenylphosphine and 2.0 phr ESBO.
Time (min)% hyd.
0 0
60 89.4
120 97.7
180 99.3
Copolymer Load: 12%: Catalyst Load: 0.045 phr; Co-catalyst Load: 1 phr.
The hydrogenation of Perbunan~ NT 3429T occurred much faster
than that of the carboxylated copolymer, Krynac~ X7.40. In general, an
acrylonitrile-butadiene copolymer can be hydrogenated easily to 97-98%
saturation, then the rate of hydrogenation slows down significantly. It is
well known that the aged properties of a hydrogenated acrylonitrile-
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butadiene copolymer improve significantly as the percent hydrogenation
approaches 100. It is economically beneficial to hydrogenate an
acrylonitrife-butadiene copolymer to greater than 99% as quickly as
possible. As shown in Table 4 and 5, the presence of ESBO increases the
rate of hydrogenation of Perbunan~ NT 3429T. Without ESBO, the
percent hydrogenation was between 96.7 and 96.9% after two hours; 98.9-
99.2% hydrogenation was achieved after four hours of reaction. With the
addition of ESBO, the percent hydrogenation was about 97.7% after two
hours. A total of 99.3% hydrogenation was achieved in only three hours of
reaction. The use of ESBO, therefore, saves about 25% reaction time.
Example 5
This example shows the hydrogenation of Perbunan~ NT 3429T
using 2 phr ESBO, in the absence of the triphenyiphosphine co-catalyst.
Following the procedure of Example 3, the hydrogenation reaction
of Perbunan~ NT 3429T (butadiene (66°l°)-acrylonitrile
(34°!°), Mooney ML
1+4 = 30) was carried out in the presence of 2 phr ESBO. The
hydrogenation results (as determined by IR spectroscopy and 1 H-NMR)
are given in Table 6.
Table 6. Hydrogenation of Perbunan~ NT 3429T in the Absence of
Triphenylphosphine Co-catalyst and in the Presence of 2 phr
ESBO.
Time (min) % hyd.
0 0
60 61.9
120 65.6
180 73.5
240 78.8
Copolymer Load: 12%; Catalyst load: 0.045 phr.
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Without the use of co-catalyst, the percent hydrogenation reached
only 78.8% after 4 hours of reaction. This result indicates that it is
necessary to have a certain amount of co-catalyst present in order to have
a reasonably fast hydrogenation reaction.
Example 6
This example shows the hydrogenation of Perbunan~ NT 3429T
using 0.3 phr triphenylphosphine co-catalyst, in the absence of ESBO.
Following the procedure of Example 3, hydrogenation reactions of
Perbunan~ NT 3429T (butadiene (66%)-acrylonitrile (34%), Mooney ML
1+4 = 30) were carried out in the absence of ESBO. The hydrogenation
results (as determined by IR spectroscopy and ~H-NMR) are given in
Table 7.
Table 7. Hydrogenation of Perbunan~ NT 3429T in the Presence of
0.3 phr Triphenylphosphine and 0 phr ESBO.
Run 1 Run 2
Time (min) % hyd. % hyd.
0 0 0
60 84.6 84 _-_ ___-_--
120 94.9 96
180 97:5 -_-. - 97.5
240 98.6 98.4
Copolymer Load: 12%; Catalyst Load: 0.045 phr; Triphenylphosphine: 0.3
phr.
When 0.3 phr TPP was used as co-catalyst, 97.5% hydrogenation
was achieved in 3 hours, but only 98.4-98.6% hydrogenation was
achieved in 4 hours of reaction, which is slower than the reaction with 1
phr triphenylphosphine (example 3, table 4).
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Example 7
This example shows the hydrogenation of Perbunan~ NT 3429T,
using 0.3 phr triphenylphosphine co-catalyst, and 2 phr ESBO.
Following the procedure of Example 3, hydrogenation reactions of
butadiene-acrylonitrile 34% ACN (Mooney ML 1+4 =30) were carried out in
the presence of 2 phr ESBO. The hydrogenation results (as determined
by 1R spectroscopy and'H-NMR) are given in Table 8.
Table 8. Hydrogenation of Perbunan~ NT 3429T in the Presence of
0.3 phr TPP and 2 phr ESBO.
Run 1 Run 2 Run 3
Time (min) % hyd. % hyd~ % hyd.
0 0 0 0
60 88.1 89.2 86.1
120 96.4 97.4 94.8
180 98.6 98.9 98.4
240-- _ -99.3- -__ -X9.5- 99.2
Substrate: Perbunan~ NT 3429 T; Copolymer load: 12%; Catalyst load:
0.045 phr; TPP: 0.3 phr.
With the use of 0.3 phr TPP co-catalyst and 2 phr ESBO, 96.4-96.6
% hydrogenation was achieved in 3 hours, and 99.2-99.5°to hydrogenation
was achieved in 4 hours of reaction. These hydrogenation results are as
good as those of reactions with 9 phr triphenylphosphine.
This example demonstrates that the addition of a proton acceptor
can reduce the amount of co-catalyst loading
and still result in enhanced hydrogenation efficiency. In this example, we
show that the presence of 2 phr ESBO can permit a reduction of 0.7 phr in
the amount of triphenylphosphine co-catalyst used.
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Although the invention has been described in detail in the foregoing
for the purpose of illustration, it is to be understood that such detail is
solely for that purpose and that variations can be made therein by those
skilled in the art without departing from the spirit and scope of the
invention except as it may be limited by the claims.
