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DESCRIPTION
CATALYST FOR DEALCOHOLIZATION CONDENSATION REACTION AND
METHOD FOR PRODUCING ORGANOPOLYSILOXANE USING THE SAME
TECHNOLOGICAL FIELD
[0001]
The present application claims priority on the basis of Japanese Patent
Application No. 2006-354812, filed in Japan on December 28, 2006, which is
hereby incorporated by reference.
[0002]
The present invention relates to a catalyst for a dealcoholization condensation
reaction comprising a quaternary ammonium ion-containing compound, and a
method for producing an organopolysiloxane by means of a dealcoholization
condensation reaction using the same.
BACKGROUND ART
[0003]
Conventionally, various basic substances, for example, basic metal salts such
as potassium hydroxide, sodium hydroxide, barium hydroxide or the like are
used as a catalyst for producing organosilicon compounds such as an
organopolysiloxane and the like via a condensation reaction of a silicon atom-
bonded hydroxy group, a silicon atom-bonded alkoxy group, or other silicon
atom-bonded functional groups.
[0004]
On the other hand, in Japanese Examined Patent Application, Second
Publication No. S46-21602; Japanese Examined Patent Application, Second
Publication No. S47-44040; Japanese Unexamined Patent Application, First
Publication No. H04-225031; and Japanese Unexamined Patent Application,
First Publication No. H05-43694, a tetramethylammonium hydroxide
compound is known as a catalyst for obtaining an organopolysiloxane with a
high molecular weight by means of ring-opening polymerization of a cyclic
siloxane with a low molecular weight such as octamethylcyclotetrasiloxane or
the like. Japanese Unexamined Patent Application, First Publication No.
2006-328231 describes that a silsesquioxane derivative having a ladder or
random structure is produced by co-hydrolyzing and co-condensing two types
of trialkoxysiloxanes, and tetramethylammonium hydroxide is used in the
Examples.
[0005]
In addition, Japanese Unexamined Patent Application, First Publication No.
S59-176326 describes a method for making a diorganopolysiloxane with a low
molecular weight in which both terminals of the molecular chain thereof are
blocked with hydroxy groups have a high molecular weight, in the presence of
a filler such as silica or the like using, as a catalyst, a reaction mixture of a
quaternary phosphonium hydroxide compound and a diorganosiloxane with a
low molecular weight.
[Patent Document 1] Japanese Examined Patent Application, Second
Publication No. S46-21602
[Patent Document 2] Japanese Examined Patent Application, Second
Publication No. S47-44040
[Patent Document 3] Japanese Unexamined Patent Application, First
Publication No. H04-225031
[Patent Document 4] Japanese Unexamined Patent Application, First
Publication No. H05-43694
[Patent Document 5] Japanese Unexamined Patent Application, First
Publication No. S59-176326
[Patent Document 6] Japanese Unexamined Patent Application, First
Publication No. 2006-328231
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0006]
In the case of using a basic metal salt as a catalyst for a condensation reaction,
it is necessary to add steps of neutralizing the basic metal salt remaining after
completion of the reaction, and removing salts formed thereby by means of
filtration or the like. In addition, in order to completely neutralize the basic
metal salt, a slightly excess amount of an acidic substance is generally used.
In this case, it is necessary to add the step of removing the excess amount of
the acidic substance after completion of the neutralization. As described
above, the method for producing an organopolysiloxane by means of a
condensation reaction with a catalyst of a basic metal salt has problems in that
the steps are complicated and waste products are increased.
[0007]
On the other hand, in the ring-opening polymerization of a cyclic siloxane with
a low molecular weight using a tetramethylammonium hydroxide compound as
a catalyst, the aforementioned problems in the case of using the basic metal
salt can be eluded. However, use of the tetramethylammonium hydroxide
compound as a catalyst of a dealcoholization condensation reaction which is
completely different from a ring-opening polymerization of a cyclic compound
has not been studied heretofore. Tetramethylammonium hydroxide used in
the Examples of Japanese Unexamined Patent Application, First Publication
No. 2006-328231 is involved in the reaction for dehydration condensation of a
silanol obtained by hydrolyzing an alkoxysilane, and is not used as a catalyst
for a dealcoholization condensation reaction
[0008]
In addition, in the case of making a diorganopolysiloxane with a low molecular
weight in which both terminals of the molecular chain thereof are blocked with
hydroxy groups have a high molecular weight, using a reaction mixture of a
quaternary phosphonium hydroxide compound and a diorganosiloxane with a
low molecular weight, as a catalyst, the reaction is a condensation reaction
between silicon atom-bonded hydroxy groups. For this reason, the conditions
of high temperature and reduced pressure are required, and a large amount of
the catalyst must be used. Therefore, the production steps are complicated.
In addition, a quaternary phosphonium hydroxide compound remains in the
system even after the activity of the compound disappears due to heat, and it
is difficult to remove the compound. For this reason, purity of a product is
reduced, and the catalyst cannot be used in usage in which high purity is
required or usage accompanied with a hydrosilylation reaction since catalyst
poisoning is exhibited. Therefore, there are the aforementioned problems.
[0009]
The present invention is performed under the circumstances of the prior art as
described above. An objective of the present invention is to provide a catalyst
for a dealcoholization condensation reaction in which it is not necessary to use
a large amount of the catalyst, and removal of the catalyst after use is easily
carried out, and thereby, establishing a method for producing an
organopolysiloxane in which waste products are reduced, and complicated
production steps are not necessary.
Means for Solving the Problems
[0010]
An objective of the present invention can be achieved by using a quaternary
ammonium ion-containing compound as a catalyst for a dealcoholization
condensation reaction of a silicon atom-bonded hydroxy group and a silicon
atom-bonded alkoxy group.
[0011]
As the aforementioned quaternary ammonium ion-containing compound, an
alkylammonium hydroxide compound or a silanolate thereof is preferable. As
the aforementioned alkylammonium hydroxide compound,
tetramethylammonium hydroxide is preferable. As the aforementioned
silanolate of the alkylammonium hydroxide compound, trimethylammonium
trimethylsilanolate or a reaction mixture of a tetramethylammonium hydroxide
compound and an organopolysiloxane is preferable. In addition, the
aforementioned alkylammonium hydroxide compound is preferably in the form
of an aqueous solution or an alcohol solution.
[0012]
The aforementioned catalyst for a dealcoholization condensation reaction is
preferably used at the time of subjecting a compound represented by the
following average structural formula (I):
wherein
each of R1 and R2 independently represents a monovalent hydrocarbon group;
0
4,
to a dealcoholization condensation reaction to produce an organopolysiloxane
represented by the following average structural formula (II):
wherein
R1, R2, a, b and c are the same as described above, with the proviso that 0
(a + b)
[0013]
The compound represented by the aforementioned average structural formula
(I) is preferably obtained by hydrolyzing an alkoxysilane represented by the
following general formula (III):
wherein
R1 and R2 are the same as described above;
a' is 0, 1,2 or 3; and b' is 1, 2, 3 or 4, with the proviso that (a' + b') = 4.
The alkoxysilane represented by the aforementioned average structural
formula (III) is preferably selected from the group consisting of
tetraalkoxysilane, monoorganotrialkoxysilane. diorganodialkoxysilane, and
mixtures thereof.
[0014]
In addition, the aforementioned catalyst for a dealcoholization condensation
reaction is also preferably used when a compound represented by the
following average structural formula (IV):
wherein each of R3 and R4 independently represents a monovalent
hydrocarbon group; 0 = d
and a compound represented by the following average structural formula (V):
wherein
R5 represents a monovalent hydrocarbon group: 0 = f
the proviso that 0
are subjected to a dealcoholization condensation reaction in a ratio in which
the number of moles of the alkoxy groups contained in the compound
represented by the aforementioned average structural formula (IV) is equal to
or more than the number of moles of the hydroxy groups contained in the
compound represented by the average structural formula (V), to produce an
organopolysiloxane represented by the following average structural formula
(vi):
wherein R3, R4 and R5 are the same as described above; 0=h
and 0 = j
The aforementioned compound represented by the aforementioned average
structural formula (IV) is preferably a tetraalkoxysilane, and the compound
represented by the aforementioned average structural formula (V) is preferably
a diorganopolysiloxane having silicon atom-bonded hydroxy groups at both
terminals of the molecular chain thereof.
EFFECTS OF THE INVENTION
[0015]
The catalyst for a dealcoholization condensation reaction according to the
present invention does not require a large amount thereof to be used, and
removal thereof after use is easily carried out. Therefore, complication of the
after-treatment steps of the dealcoholization condensation reaction can be
eluded, and purity of a product can be increased. In addition, increase of
waste products can be controlled.
[0016]
Thereby, a method for producing an organopolysiloxane according to the
present invention does not require complicated production steps, and can
elude use of a large amount of the catalyst. In addition, the method for
producing an organopolysiloxane according to the present invention is not
performed via a condensation reaction between hydroxy groups. For this
reason, reaction conditions of high temperature and reduced pressure can be
alleviated. In view of this, complication of production steps can be eluded.
[0017]
Therefore, the catalyst for a dealcoholization condensation reaction and the
method for producing an organopolysiloxane using the same according to the
present invention are practically advantageous, and environmental burden can
be reduced.
BEST MODES FOR CARRYING OUT THE INVENTION
[0018]
The catalyst for a dealcoholization condensation reaction according to the
present invention promotes a dealcoholization condensation reaction between
a silicon atom-bonded hydroxy group and a silicon atom-bonded alkoxy group,
and comprises a quaternary ammonium ion-containing compound. The term
"comprise" used herein means not only the case of consisting of only a
quaternary ammonium ion-containing compound, but also the case of
containing a quaternary ammonium ion-containing compound as the main
catalyst component and other additional components.
[0019]
The quaternary ammonium ion-containing compound is not particularly limited
as long as a quaternary ammonium group is possessed. The compound is
preferably basic. As examples of a basic compound having a quaternary
ammonium ion, mention may be made of an alkylammonium hydroxide
compound.
[0020]
As the alkyl group forming the alkylammonium hydroxide compound, an alkyl
group having 1 to 6 carbon atoms is preferable, and examples thereof include
a methyl group, an ethyl group, a propyl group, and the like. A reduced
number of the carbon atoms is preferable, and in particular, a methyl group is
preferable. Therefore, as examples of alkylammonium hydroxide compounds,
mention may be made of tetramethylammonium hydroxide,
tetraethylammonium hydroxide, tetrapropylammonium hydroxide,
tetrabutylammonium hydroxide, and the like. In particular,
tetramethylammonium hydroxide is preferable.
[0021]
A silanolate of an alkylammonium hydroxide compound can also be used as
the quaternary ammonium ion-containing compound.
[0022]
As examples of silanolates of the alkylammonium hydroxide compounds,
mention may be made of, for example, tetramethylammonium
trimethylsilanolate, tetraethylammonium trimethylsilanolate,
tetrapropylammonium trimethylsilanolate, tetramethylammonium
triethylsilanolate, tetraethylammonium triethylsilanolate, tetrapropylammonium
triethylsilanolate, tetramethylammonium tripropylsilanolate,
tetraethylammonium tripropylsilanolate, tetrapropylammonium
tripropylsilanolate, and the like. In particular, tetramethylammonium
trimethylsilanolate, {(CH3)4N-OSi(CH3)3}, is preferable. As the
aforementioned silanolates, those produced by any method can be used. For
example, the silanolates can be prepared by a dehydration reaction between a
tetraalkylammonium hydroxide compound and a silanol compound.
[0023]
As a silanolate of an alkylammonium hydroxide compound, a reaction mixture
between an alkylammonium hydroxide compound and an organopolysiloxane
can also be used. The organopolysiloxane is not particularly limited as long
as it can react with the hydroxy group of the alkylammonium hydroxide
compound. As examples of organopolysiloxanes, mention may be made of,
for example, straight-chain polysiloxanes such as hexamethyldisiloxane,
octamethyltrisiloxane, and the like; cyclic siloxanes such as
decamethylcyclopentasiloxane, octamethylcyclotetrasiloxane,
hexamethylcyclotrisiloxane, and the like; and the like. Preferable examples of
the reaction mixture are represented by the following formula:
wherein
n is an integer of one or more.
[0024]
The catalyst for a dealcoholization condensation reaction according to the
present invention may be used as a single type of a quaternary ammonium
ion-containing compound, or in combination with two or more types thereof.
[0025]
In the case of using a tetraalkylammonium hydroxide compound as a
quaternary ammonium ion-containing compound, any tetraalkylammonium
hydroxide compounds produced by any methods can be used. For example,
a tetraalkylammonium hydroxide compound can be produced by means of an
electrolysis method in which an aqueous solution of a tetraalkylammonium
compound such as tetraalkylammonium halide is supplied to a positive
electrode chamber of an electrolytic cell which is distinguished between the
positive electrode chamber and a negative electrode chamber by a
fluorocarbon-based positive ion exchange membrane, electrolysis is carried
out while water is being provided to the aforementioned positive electrode
chamber, and subsequently, an aqueous solution of a tetraalkylammonium
hydroxide is extracted from the negative electrode chamber, as described in
Japanese Unexamined Patent Application, First Publication No. S61-190085.
[0026]
The aforementioned tetraalkylammonium hydroxide compound is preferably
used by diluting in a suitable solvent in view of stability, and is, in particular, in
the form of an aqueous solution or an alcohol solution.
[0027]
In the method for producing an organopolysiloxane of the present invention, an
organopolysiloxane is synthesized by means of a dealcoholization
condensation reaction between a silicon atom-bonded hydroxy group and a
silicon atom-bonded alkoxy group in the presence of a quaternary ammonium
ion-containing compound, as a catalyst, which is preferably an alkylammonium
hydroxide compound or a silanolate thereof. In the method for producing the
organopolysiloxane of the present invention, the organopolysiloxane can be
easily produced since the method is performed not via a condensation reaction
between silicon atom-bonded hydroxy groups, which requires the conditions of
high temperature and reduced pressure.
[0028]
For example, according to the present invention, a compound represented by
the following average structural formula (I):
wherein
each of R1 and R2 independently represents a monovalent hydrocarbon
group;0 = a
+ c)
is subjected to a dealcoholization condensation reaction in the presence of a
quaternary ammonium ion-containing compound, and thereby, an
organopolysiloxane represented by the following average structural formula
(II):
wherein
R1, R2, a, b and c are the same as described above, with the proviso that 0
(a + b)
can be produced. In the aforementioned formula, c
[0029]
The aforementioned monovalent hydrocarbon group may be a straight-chain,
branched or cyclic hydrocarbon group, having 1 to 30 carbon atoms. As
examples of the aforementioned hydrocarbon group, mention may be made of
a straight-chain, branched or cyclic alkyl group having 1 to 30 carbon atoms, a
straight-chain, branched or cyclic alkenyl group having 2 to 30 carbon atoms,
an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30
carbon atoms, and the like.
[0030]
As examples of the aforementioned straight-chain, branched or cyclic alkyl
groups, mention may be made of, for example, a methyl group, an ethyl group,
a n-propyl group, an iso-propyl group, a n-butyl group, an iso-butyl group, a
sec-butyl group, a tert-butyl group, a n-pentyl group, an iso-pentyl group, a
sec-pentyl group, a neopentyl group, a tert-pentyl group, a cyc-pentyl group, a
n-hexyl group, an iso-hexyl group, a sec-hexyl group, a neohexyl group, a cyc-
hexyl group, a n-heptyl group, an iso-heptyl group, a sec-heptyl group, a
neoheptyl group, a cyc-heptyl group, a n-octyl group, an iso-octyl group, a sec-
octyl group, a neooctyl group, a cyc-octyl group, a n-nonyl group, an iso-nonyl
group, a sec-nonyl group, a neononyl group, a cyc-nonyl group, a decyl group,
an undecyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and
an octadecyl group.
[0031]
As examples of the aforementioned straight-chain, branched or cyclic alkenyl
groups, mention may be made of, for example, a vinyl group, an allyl group, a
butenyl group, a hexenyl group, and the like.
[0032]
As examples of the aforementioned aryl groups, mention may be made of a
phenyl group, a tolyl group, a naphthyl group, and the like.
[0033]
As examples of the aforementioned arylalkyl groups, mention may be made of
a phenethyl group, a benzyl group, and the like.
[0034]
The aforementioned hydrocarbon group may be either substituted or non-
substituted. In the case of substituted hydrocarbon groups, as examples of
the substituents, mention may be made of, for example, a halogen atom such
as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or the
like; an alkoxy group such as a methoxy group, an ethoxy group, a propoxy
group, or the like; a cyano group; and the like. Therefore, as examples of the
substituted hydrocarbon groups, mention may be made of, for example, a 3-
chloropropyltrimethoxy group, a 3-bromopropyl group, a 3,3,3-trifluoropropyl
group, a cyanoethyl group, and the like.
[0035]
A method for producing an acyclic compound represented by the
aforementioned average structural formula (I) is not particularly limited. For
example, an alkoxysilane represented by the following general formula (III):
wherein
R1 and R2 are the same as described above;
a' is 0, 1, 2 or 3; b' is 1, 2, 3 or 4, with the proviso that (a' + b') = 4,
is hydrolyzed, and thereby, the aforementioned acyclic compound can be
obtained. The alkoxysilanes represented by the aforementioned general
formula (III) may be used as a single type thereof or as a mixture of two or
more types thereof.
[0036]
As examples of the compounds represented by the aforementioned average
structural formula (I), mention may be made of, for example, an
organopolysiloxane obtained by hydrolyzing an alkoxysilane of the
aforementioned general formula (III) wherein a' and b' are respectively 0 and 4,
i.e., a tetraalkoxysilane; an alkoxysilane of the aforementioned general formula
(III) wherein a' and b' are respectively 1 and 3, i.e., a
monoorganotrialkoxysilane; or a mixture thereof; as well as, an
organopolysiloxane obtained by hydrolyzing a mixture produced by adding an
alkoxysilane of the aforementioned general formula (III) wherein both a' and b'
are 2, i.e., a diorganodialkoxysilane, an alkoxysilane of the aforementioned
general formula (III) wherein a' and b' are respectively 3 and 1, i.e., a
triorganomonoalkoxysilane, or a mixture thereof to the aforementioned
tetraalkoxysilane, the aforementioned monoorganotrialkoxysilane, or a mixture
thereof.
[0037]
As examples of the alkoxysilanes represented by general formula (III), mention
may be made of, for example, a tetraalkoxysilane such as tetramethoxysilane,
tetraethoxysilane, or the like; a monoorganotrialkoxysilane such as
methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane,
methyitributoxysiiane, ethyitrimethoxysiiane, ethyltriethoxysilane,
ethyltripropoxysilane, ethyltributoxysilane, propyltrimethoxysilane,
propyltriethoxysilane, propyltripropoxysilane, propyltributoxysilane,
butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane,
butyltributoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane,
hexyltripropoxysilane, hexyltributoxysilane, cyclopentylthmethoxysilane,
cyclopentyltriethoxysilane, cyclopentyltripropoxysilane,
cyclopentyltributoxysilane, cyclohexyltrimethoxysilane,
cyclohexyltriethoxysilane, cyclohexyltripropoxysilane, cyclohexyltributoxysilane,
vinyltrimethoxysilane, allyltrimethoxysilane, butenyltrimethoxysilane,
hexenyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-
bromopropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 2-
cyanoethyltrimethoxysilane, phenyltrimethoxysilane, naphthyltrimethoxysilane,
phenethylmethoxysilane, or the like; a diorganodialkoxysilane such as
dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane,
dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,
diethyldipropoxysilane, diethyldibutoxysilane, dipropyldimethoxysilane,
dipropyldiethoxysilane, dipropyldipropoxysilane, dipropyldibutoxysilane,
dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldipropoxysilane,
dibutyldibutoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane,
dihexyldipropoxysilane, dihexyldibutoxysilane, dicyclopentyldimethoxysilane,
dicyclopentyldiethoxysilane, dicyclopentyldipropoxysilane,
dicyclopentyldibutoxysilane, dicyclohexyldimethoxysilane,
dicyclohexyldiethoxysilane or the like; and a triorganomonoalkoxysilane such
as trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane,
trimethylbutoxysilane, triethylmethoxysilane, triethylethoxysilane,
triethylpropoxysilane, triethylbutoxysilane, tripropylmethoxysilane,
tripropylethoxysilane, tripropylpropoxysilane, tripropylbutoxysilane,
tributylmethoxysilane, tributylethoxysilane, tributylpropoxysilane,
tributylbutoxysilane, trihexylmethoxysilane, trihexylethoxysilane,
trihexylpropoxysilane, trihexylbutoxysilane, tricyclopentylmethoxysilane,
tricyclopentylethoxysilane, tricyclopentylpropoxysilane,
tricyclopentylbutoxysilane, tricyclohexylmethoxysilane,
tricyclohexylethoxysilane or the like. It should be understood that the
alkoxysilanes represented by the aforementioned general formula (III) are not
limited to the aforementioned ones.
[0038]
In order to promote hydrolysis of the alkoxysilane represented by general
formula (III), an acidic or basic catalyst is preferably used. As the acidic
catalyst, for example, an inorganic acid such as hydrochloric acid, sulfuric acid
or the like, or an organic acid such as acetic acid or the like can be used. As
the basic catalyst, an inorganic base such as sodium hydroxide, potassium
hydroxide or the like, a basic compound containing a quaternary ammonium
ion, and the like can be used. The reaction temperature of the hydrolysis
reaction is not particularly limited, and preferably ranges from 20 to 80°C and
more preferably ranges from 30 to 60°C. The reaction pressure of the
hydrolysis reaction is not particularly limited, and is preferably a normal
pressure in view of operationability.
[0039]
The compound represented by the aforementioned average structural formula
(I) has both a silicon atom-bonded alkoxy group and a silicon atom-bonded
hydroxy group per molecule. Therefore, the condensation reaction of the
compound represented by the aforementioned average structural formula (I)
corresponds to a dealcoholization condensation reaction of the compounds,
each compound having both a silicon atom-bonded alkoxy group and a silicone
atom-bonded hydroxy group per molecule. The compounds represented by
the aforementioned average structural formula (I) may be used as a single type
thereof, or as a mixture of two or more types thereof.
[0040]
In addition, in the present invention, a compound represented by the following
average structural formula (IV):
wherein
each of R3 and R4 independently represents a monovalent hydrocarbon group;
0 = d
and a compound represented by the following average structural formula (V):
wherein
R5 represents a monovalent hydrocarbon group; 0 = f
the proviso that 0
are subjected to a dealcoholization condensation reaction in the presence of a
quaternary ammonium ion-containing compound. Thereby, an
organopolysiloxane represented by the following average structural formula
(VI):
wherein
R , R4 and R5 are the same as described above; 0=h
4, with the proviso that 0
The monovalent hydrocarbon group used herein is the same as described in
R1 and R2 of the aforementioned average structural formula (I). In the
aforementioned formula, 0
[0041]
The compound represented by the aforementioned average structural formula
(IV) has a silicon atom-bonded alkoxy group, and the compound represented
by the aforementioned average structural formula (V) has a silicon atom-
bonded hydroxy group. Therefore, the condensation reaction between the
compound represented by the aforementioned average structural formula (IV)
and the compound represented by the aforementioned average structural
formula (V) corresponds to a dealcoholization condensation reaction between
the compound having a silicon atom-bonded alkoxy group and the compound
having a silicon atom-bonded hydroxy group. When the condensation
between the compound of the aforementioned average structural formula (IV)
and the compound of the average structural formula (V) is carried out in a ratio
in which the number of moles of the alkoxy groups contained in the compound
of the aforementioned average structural formula (IV) is equal to or more than
the number of moles of the hydroxy groups contained in the compound of the
average structural formula (V), and preferably in a ratio in which the number of
moles of the alkoxy groups contained in the compound of the aforementioned
average structural formula (IV) is equal to or more than twice the number of
moles of the hydroxy groups contained in the compound of the average
structural formula (V), an organopolysiloxane represented by the
aforementioned average structural formula (VI) which substantially contains no
hydroxy groups can be obtained. The compounds represented by the
aforementioned average structural formula (IV) and the aforementioned
average structural formula (V) may be used as a single type thereof or as a
mixture of two or more types of each or both thereof. The compounds
represented by the aforementioned average structural formula (IV) and the
aforementioned average structural formula (V) are silanes or
organopolysiloxanes having a straight-chain or branched molecular structure.
As examples of the organopolysiloxanes represented by the aforementioned
average structural formula (VI), mention may be made of, for example, an
organopolysiloxane obtained by means of condensation between a compound
of the aforementioned formula (IV) wherein d and e are respectively 0 and 4,
i.e., a tetraalkoxysilane; or a compound of the aforementioned formula (IV)
wherein d and e are respectively 1 and 3, i.e., a monoorganotrialkoxysilane;
and a compound of the aforementioned average structural formula (V) wherein
1.95
diorganopolysiloxane.
[0042]
The usage amount of the catalyst for a dealcoholization condensation reaction
formed from the quaternary ammonium ion-containing compound in the
method for producing an organopolysiloxane of the present invention may be
an amount by which the silicon atom-bonded hydroxy group or the silicon
atom-bonded alkoxy group of the starting substances can interact with each
other. In general, the catalyst for a dealcoholization condensation reaction is
preferably used in an amount ranging from 0.5 to 100,000 ppm, and preferably
ranging from 10 to 10,000 ppm, with respect to the weight of the starting
materials. If the usage amount thereof is below 0.5 ppm, the rate of the
condensation reaction may be extremely reduced. On the other hand, if the
usage amount exceeds 100,000 ppm, excessive time may be required in order
to remove the catalyst after the condensation reaction.
[0043]
The dealcoholization condensation reaction in the method for producing an
organopolysiloxane of the present invention is preferably carried out at a
temperature which is equal to or lower than the thermal decomposition
temperature of the catalyst for a dealcoholization condensation reaction
comprising the quaternary ammonium ion-containing compound. In general,
the aforementioned reaction is carried out at not more than 120°C and more
preferably not more than 100°C, although the thermal decomposition
temperature of the aforementioned catalyst varies depending on the types of
the aforementioned catalysts.
[0044]
The reaction pressure of the aforementioned dealcoholization condensation
reaction is not particularly limited. Normal pressure is preferably in view of
operationability.
[0045]
In the method for producing an organopolysiloxane of the present invention,
after the aforementioned dealcoholization, the remaining catalyst is preferably
removed. The removal of the remaining catalyst can be carried out by, for
example, heating the aforementioned catalyst to a temperature which is equal
to or higher than the thermal decomposition temperature of the quaternary
ammonium ion-containing compound which forms the aforementioned catalyst
to obtain substances with a low boiling temperature, and subsequently
removing the substances from the reaction system by means of an operation
under reduced pressure or the like. The heating temperature is, for example,
equal to or higher than 120°C, and preferably equal to or higher than 130°C.
[0046]
For example, tetraalkylammonium hydroxide is thermally decomposed to
compounds with a low boiling point such as an amine (such as trimethylamine)
and an alcohol (such as methanol) at a temperature which is equal to or higher
than the thermal decomposition temperature by means of a reaction shown by
the following scheme:
wherein
R1 represents an alkyl group such as a methyl group, an ethyl group, a propyl
group, or the like.
In addition, the compounds with a low boiling point can be easily removed
under reduced pressure. For this reason, the tetraalkyiammonium hydroxide
remaining in the reaction system can be easiiy removed. The thermal
decomposition reaction of the tetraalkyiammonium hydroxide is carried out
under reduced pressure and thereby, the removal of the compounds with a low
boiling point produced by the thermal decomposition may be promoted, if
necessary.
[0047]
As described above, in the present invention, a neutralization step is not
required for removal of the remaining catalyst after the reaction. For this
reason, complication of the steps of producing an organopolysiloxane and
increase of waste products can be eluded. Therefore, the catalyst for a
dealcoholization condensation reaction comprising the quaternary ammonium
ion-containing compound in the present invention is practically advantageous.
[0048]
The organopolysiloxane represented by the aforementioned average structural
formula (II) or (VI) which is obtained by the dealcoholization condensation
reaction is a straight-chain or branched organopolysiloxane or organosiloxane
oligomer, and in general, has a molecular weight ranging from 162 to
1,000,000. In addition, the outer appearance of the organopolysiloxane
represented by the aforementioned average structural formula (II) or (VI) may
vary in the form of an oil, a gum, or a resin, depending of the molecular weight
and molecular structure thereof.
INDUSTRIAL APPLICABILITY
[0049]
The organopolysiloxane represented by the aforementioned average structural
formula (II) or (VI) which is obtained by the method for producing the same of
the present invention can be suitably used in various usages.
[0050]
In particular, when the organopolysiloxane represented by the aforementioned
average structural formula (II) or (VI) has an alkoxy group, a reaction such as
crosslinking or the like can be carried out by using the aforementioned alkoxy
group as a reaction point. Therefore, by use of the organopolysiloxane
represented by the aforementioned average structural formula (II) or (VI), a
silicone composition can be obtained which is useful as a mono-component
type and di-component type curable silicone composition suitable for use in
civil engineering and construction; a binder, a surface treatment agent, a
sealant, a water repellant, a coating agent for use in electrical insulating, and a
painting composition for structural materials as well as various powders
suitably used in coating agents; catalyst components for olefin polymerization
or the like; a resin modifier composition; or the like.
EXAMPLES
[0051]
Hereinafter, the present invention is described in detail with reference to
Examples. It should be understood that the present invention is not limited to
the Examples.
[0052]
Preparation Example 1
412.8 g (2 mol) of hexyltrimethoxysilane, 20 g of methanol and 0.20 g (0.0020
mol) of concentrated sulfuric acid were placed in a four-neck flask with a
volume of 500 ml, equipped with a thermometer, a dripping funnel and a
stirring device, and the mixture was stirred. 27.0 g (1.5 mol) of water was
added dropwise thereto at room temperature over 20 minutes. The
temperature of the reaction mixture was increased by 16°C by progressing a
hydrolysis reaction and a condensation reaction. The reaction mixture after
the drop treatment was stirred for 30 minutes at 60°C, and a partial hydrolysis
reaction was completed. Subsequently, the reaction mixture was stirred for
10 minutes at 60°C under reduced pressure of 1 kPa. After methanol
produced in the hydrolysis reaction and the condensation reaction was
removed, the reaction mixture was cooled to room temperature. As a result,
336.7 g of an organopolysiloxane containing a hexyl group was obtained. The
aforementioned partial hydrolysate was used in the following Example 1 and
Comparative Example 1.
[0053]
Example 1
0.70 g (0.002 mol) of a 26% aqueous solution of tetramethylammonium
hydroxide was added to 160 g of the organopolysiloxane containing a hexyl
group prepared in Preparation Example 1. The mixture was stirred for 30
minutes at room temperature and was stirred for 30 minutes at 60°C, and
thereby, a condensation reaction was completed. The reaction mixture
exhibited an alkaline property with pH test paper.
[0054]
The reaction mixture was gradually heated to 100°C. As a result, removal by
distillation of methanol produced by the condensation reaction was observed.
In addition, the reaction mixture was further heated for one hour at 130oC. As
a result, it was confirmed that trimethylamine which was a basic gas produced
by thermal decomposition of tetramethylammonium hydroxide used as a
catalyst for the condensation reaction generated in a gaseous phase in the
flask. The reaction mixture was stirred for 10 minutes at the same
temperature as described above under reduced pressure of 1 kPas, and
thereby, volatile components were removed. As a result, the mixture
exhibited a neutral property with pH test paper.
[0055]
The aforementioned reaction mixture was filtered under reduced pressure.
Thereby, 149.8 g of a neutral organopolysiloxane containing a hexyl group was
obtained. The viscosity thereof was 16 mm2/sec. Even after the product
was stored for 6 months at room temperature, the viscosity did not change and
the product was stable. The average structural formula obtained by means of
C NMR was n-C6H13SiOo.7o(OCH3)1.6o- The number average molecular
weight thereof obtained by means of GPC using toluene as a solvent was 375,
and the weight average molecular weight was 959.
[0056]
Comparative Example 1
160 g of the organopolysiloxane containing a hexyl group prepared in
Preparation Example 1 and 0.23 g (0.002 mol) of a 48% aqueous solution of
potassium hydroxide were placed in a four-neck flask with a volume of 500 ml,
equipped with a thermometer, a dripping funnel and a stirring device, and the
mixture was stirred for 30 minutes at room temperature, and then was stirred
for 30 minutes at 60°C. Thereby, a condensation reaction was completed.
The reaction mixture exhibited an alkaline property with pH test paper.
[0057]
The reaction mixture was gradually heated to 100°C. As a result, removal by
distillation of methanol produced by the condensation reaction was observed.
In addition, the reaction mixture was further heated for one hour at 130°C,
followed by stirring for 30 minutes under reduced pressure of 1 kPas to remove
volatile components. The resultant mixture was cooled to room temperature.
The reaction mixture exhibited an alkaline property with pH test paper.
[0058]
Subsequently, in order to neutralize the condensation catalyst, 0.1 g (0.0017
mol) of acetic acid was added thereto. The mixture was stirred for 30 minutes
at 100°C, followed by stirring for 30 minutes under reduced pressure of 100
Pas to remove volatile components. Subsequently, the mixture was cooled to
room temperature.
[0059]
The mixture was filtered under reduced pressure. Thereby, 145.6 g of a
neutral organopolysiloxane containing a hexyl group was obtained. The
viscosity was 17 mm2/sec. Even after the product was stored for 6 months at
room temperature, the viscosity thereof did not change and was stable. The
average structural formula obtained by means of 13C NMR was n-
C6H13SiO0.74(OCH3)1.52. The number average molecular weight obtained by
means of GPC using toluene as a solvent was 408, and the weight average
molecular weight was 1062.
[0060]
Example 2
200 g of a polydimethylsiloxane (average polymerization degree = 40) in which
both terminals of the molecular chain thereof were blocked with hydroxy
groups and 80 g of tetramethoxysilane were placed in a four-neck flask with a
volume of 500 ml, equipped with a thermometer, a dripping funnel and a
stirring device. In addition, 2.0 g (0.002 mol) of a 26% methanol solution of
tetramethylammonium hydroxide was added thereto, followed by mixing.
Immediately after mixing, the mixture was a uniform solution which was
colorless and transparent. The solution exhibited an alkaline property with pH
test paper. As a result of stirring the mixture for 30 minutes at room
temperature, the colorless transparent reaction mixture became a clouded
mixture. Subsequently, the mixture was stirred for 30 minutes at 60°C to
complete the condensation reaction. The reaction mixture exhibited an
alkaline property with pH test paper.
[0061]
The reaction mixture was gradually heated to 100°C. As a result, removal by
distillation of methanol produced by the condensation reaction was observed.
In addition, the reaction mixture was further heated for one hour at 130°C. As
a result, it was confirmed that trimethylamine which was a basic gas produced
by thermal decomposition of tetramethylammonium hydroxide used as a
catalyst for the condensation reaction generated in a gaseous phase in the
flask. The reaction mixture was stirred for 10 minutes at the same
temperature as described above under reduced pressure of 1 kPas, and
thereby, volatile components were removed. As a result, the mixture
exhibited a neutral property with pH test paper.
[0062]
The aforementioned reaction mixture was filtered under reduced pressure.
Thereby, 149.8 g of a neutral polydimethylsiloxane in which both the terminals
of the molecular chain thereof were blocked by trimethoxysilyl groups was
obtained. The viscosity thereof was 127 mm2/sec. The average structural
formula obtained by means of 13C NMR was (CH3)1.91SiO0.98(OCH3)0.14. The
number average molecular weight thereof obtained by means of GPC using
toluene as a solvent was 4.7 x 103, and the weight average molecular weight
was 9.8 x 103. From 29Si NMR analysis, it was confirmed that the hydroxy
groups at the terminals of the molecular chain did not remain.
CLAIMS
1. A catalyst for a dealcoholization condensation reaction between a silicon
atom-bonded hydroxy group and a silicon atom-bonded alkoxy group,
comprising a quaternary ammonium ion-containing compound.
2. The catalyst for a dealcoholization condensation reaction according to
claim 1, wherein said quaternary ammonium ion-containing compound is
an alkylammonium hydroxide compound or a silanolate thereof.
3. The catalyst for a dealcoholization condensation reaction according to
claim 2, wherein said alkylammonium hydroxide compound is
tetramethylammonium hydroxide.
4. The catalyst for a dealcoholization condensation reaction according to
claim 2 or 3, wherein said alkylammonium hydroxide compound is in the
form of an aqueous solution or an alcohol solution.
5. The catalyst for a dealcoholization condensation reaction according to
claim 2, wherein the silanolate of said alkylammonium hydroxide
compound is tetramethylammonium trimethylsilanolate or a reaction
mixture between a tetramethylammonium hydroxide compound and an
organopolysiloxane.
6. A method for producing an organopolysiloxane represented by the
following average structural formula (II), characterized by subjecting a
compound represented by the following average structural formula (I):
wherein
each of R1 and R2 independently represents a monovalent hydrocarbon
group; 0=a
+ b + c)
to a dealcoholization condensation reaction in the presence of the catalyst
as recited in any one of claims 1 to 5 to produce the organopolysiloxane
represented by the following average structural formula (II):
wherein
R1, R2, a, b and c are the same as described above, with the proviso that 0
7. The method according to claim 6, wherein the compound represented by
said average structural formula (I) is obtained by hydrolyzing an
alkoxysilane represented by the following general formula (III):
wherein
R1 and R2 are the same as described above;
a' is 0, 1,2 or 3; and b' is 1, 2, 3 or 4, with the proviso that (a' + b') = 4.
8. The method according to claim 7, wherein the alkoxysilane represented by
said average structural formula (III) is an alkoxysilane selected from the
group consisting of a tetraalkoxysilane, monoorganotrialkoxysilane,
diorganodialkoxysilane, and a mixture thereof.
9. A method for producing an organopolysiloxane represented by the
following average structural formula (VI), characterized by subjecting a
compound represented by the following average structural formula (IV):
wherein
each of R3 and R4 independently represents a monovalent hydrocarbon
group; 0 = d
and a compound represented by the following average structural formula
(V):
wherein
R5 represents a monovalent hydrocarbon group; 0 = f
with the proviso that 0
to a dealcoholization condensation reaction in the presence of the catalyst
as recited in any one of claims 1 to 5 in a ratio in which the number of
moles of the alkoxy group contained in the compound represented by the
following average structural formula (IV) is equal to or more than the
number of moles of the hydroxy group contained in the compound
represented by the average structural formula (V), to produce said
organopolysiloxane represented by the following average structural
formula (VI):
wherein
R3, R4 and R5 are the same as described above; 0 = h
= j
10. The method according to claim 9, wherein the compound represented by
said average structural formula (IV) is a tetraalkoxysilane, and the
compound represented by said average structural formula (V) is a
diorganopolysiloxane having silicon atom-bonded hydroxy groups at both
terminals of the molecular chain thereof.
A quaternary ammonium ion-containing compound such as an alkylammonium hydroxide compound or a silanolate
thereof is used as a catalyst when an orgaDopolysiloxane is produced by a dealcoholization condensation reaction of a silicon atom-
bonded hydroxy group and a silicon atom-bonded alkoxy group. Since this catalyst for dealcoholization condensation reaction is
stable and can be easily removed after use, no complicated step is required when an organopolysiloxane is produced by using this
catalyst In addition, this catalyst is not required in a large amount for the production of an organopolysiloxane. |