JP2001270887A - Method for manufacturing cyclic oligosiloxane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a practical method for manufacturing a cyclic oligosiloxane in which a cyclic oligosiloxane is manufactured by heating a linear or cyclic polysiloxane in the presence or absence of a catalyst, and the reaction can be stopped directly before the gelation of the reaction mixture by monitoring the reaction. SOLUTION: The reaction is monitored based on the reflective index of the reaction mixture, and the terminal point of the reaction is determined using the reflective index as a parameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compound represented by the following general formula (III) used as a raw material in the silicone industry:

[0002]

Embedded image And a method for producing a cyclic oligosiloxane represented by the formula:

[0003]

BACKGROUND OF THE INVENTION Cyclic oligosiloxanes are used in the silicone industry as raw materials for the production of high molecular weight polysiloxanes. Further, cyclic oligosiloxanes containing Si—H groups are used as raw materials for producing room temperature cross-linkable silicone rubber used for sealants and the like in the silicone industry. The room temperature crosslinkable silicone rubber can be obtained by reacting a cyclic oligosiloxane containing a Si—H group with a polysiloxane containing a vinyl group in the presence of a platinum catalyst to cause crosslinking. Further, the cyclic oligosiloxane containing a Si-H group is also used as a raw material for producing an organic functional group-bonded oligosiloxane used as an adhesion promoter or the like. The organic functional group-bonded oligosiloxane is obtained by reacting a cyclic oligosiloxane containing a Si-H group with an organic group containing a vinyl group in the presence of a platinum catalyst.

[0004] As a method for producing a cyclic oligosiloxane, for example, a method in which 2
A method of hydrolyzing and condensing organosilanes having one hydrolyzable group is generally known. However,
Under such hydrolysis-condensation reaction conditions, the reaction system becomes severe in an acidic condition, which is not advantageous for industrially stable production. Particularly in the production of a cyclic oligosiloxane containing a Si-H group, the Si-H group has a very high reactivity under such acidic conditions and reacts with water or a silanol group coexisting in the reaction system. The yield of the compound is low.

Therefore, as another method for producing a cyclic oligosiloxane, a method has been proposed in which a chain polysiloxane or a highly polymerized cyclic polysiloxane is reacted under various conditions in the presence of an acidic or alkaline catalyst. I have.

[0006] Among these methods, in particular, Si—H
In a system having a group, the Si-H group has a high reactivity with water in an acidic or alkaline state, and thus has a problem that the reaction system gels during the reaction or at the end of the reaction.

[0007] In order to solve such a problem, the inventors of the present invention have carried out an industrial process which can carry out a reaction under neutral conditions, and particularly does not involve gelation of the reaction system even in a system containing a Si-H group. As a practical method for producing a cyclic oligosiloxane, a method for producing a cyclic oligosiloxane characterized by heating a chain or cyclic polysiloxane in the presence of a metal alkoxide has been found. This reaction can be carried out substantially without gelation of the reaction system.However, when the reaction is carried out at a high temperature for a very long time under conditions with a large amount of catalyst, or at the very end of the reaction, Under such special circumstances, it has been found that there is still a problem that a part of the reaction residue is gelled.

When the reaction solution gels, it becomes very difficult to clean the reactor to carry out the reaction again, which is a fatal problem in industrial use.

If the reaction is terminated before the reaction solution is sufficiently gelled, for example, at the beginning of the reaction, gelation of the reaction solution can be prevented, but in that case, the reaction yield is greatly reduced. However, the production cost is increased, and this is not advantageous in industrial use.

In order to stop the reaction before the reaction solution gels, it is necessary to monitor the reaction by some method. As a method, there is a method of monitoring the reaction time or the amount of the product to be distilled out based on the ratio to the charged raw material. The temperature varies depending on reaction conditions such as reaction temperature, amount of catalyst, reaction pressure, reflux ratio and the like, and is not constant. In addition, this method is not a practical method because the effect of a slight shift in the reaction conditions is large.

As another method of monitoring the reaction solution, there is a method of observing the viscosity of the reaction solution or the load of a stirring motor. However, in the case of the reaction described in the present invention, the change in the viscosity of the reaction solution is generally rapid, Shows a tendency to rapidly increase the viscosity immediately before the formation. Therefore, even if the reaction is actually monitored by this method, it is difficult to terminate the reaction before gelation, and this method is not a practical method.

[0012]

Accordingly, the present invention provides a method for producing a cyclic oligosiloxane by heating a linear or cyclic polysiloxane in the presence or absence of a catalyst. It is an object of the present invention to provide a practical method for producing a cyclic oligosiloxane capable of monitoring the reaction and terminating the reaction immediately before the reaction solution gels.

[0013]

Means for Solving the Problems In order to solve such problems, the present inventors have conducted intensive studies and, as a result, monitored the reaction by the refractive index of the reaction solution, and determined the reaction end point by using this as an index. The present inventors have found that the reaction can be terminated immediately before the reaction solution gels, and have reached the present invention.

That is, the present invention relates to a method for producing a cyclic oligosiloxane by heating a linear or cyclic polysiloxane in the presence or absence of a catalyst, wherein the reaction is monitored by the refractive index of a reaction solution. A method for producing a cyclic oligosiloxane (Claim 1), characterized by the following general formula (I):

[0015]

Embedded image (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² is a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ is a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ^{4 to} R ⁶ are the same or different monovalent substituted or Represents an unsubstituted hydrocarbon group, k and l are each independently 0 or a number from 1 to 1000, and k and l represent numbers satisfying 4 ≦ k + 1 ≦ 1000. ) And / or the following general formula (II)

[0016]

Embedded image (Wherein, R ^{4 to} R ⁶ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, m and n are each independently 0 or a number from 1 to 1000, and m and n
Represents a number satisfying 3 ≦ m + n ≦ 1000. ) Is heated in the presence or absence of a catalyst to form a cyclic polysiloxane represented by the following general formula (III):

[0017]

Embedded image (Wherein, R ^{4 to} R ⁶ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, p and q each independently represent a number of 0 or 1 to 10, and p and q represent 3
≤p + q≤10. ), Wherein the reaction is monitored based on the refractive index of the reaction solution (Claim 2).
Are each independently 0 or a number from 1 to 999, and the l and n are each independently a number from 1 to 1000, the p is a number from 0 or 1 to 9, and the q is 1 The method for producing a cyclic oligosiloxane according to claim 2, wherein the number of k, l, and
m, n, p, and q are 5 ≦ m + n ≦ 1000 and p + q <k
4. The method for producing a cyclic oligosiloxane according to claim 3, wherein the number satisfies + l and p + q <m + n, wherein R ¹ , R ⁴ and R ⁶ are methyl groups, and R ² is a hydroxyl group or methyl. 5. The method for producing a cyclic oligosiloxane according to claim 2, wherein the group and R ³ are a hydrogen atom or a methyl group (claim 5).
The method according to any one of claims 2 to 5, wherein l, m, n, p, and q are k <l, m <n, and p <q (claim 6). Yes, k = m
= P = 0, the method for producing a cyclic oligosiloxane according to any one of claims 3 to 5 (claim 7), wherein [1] the following general formula (IV):

[0018]

Embedded image (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ represents a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ⁴ represents a monovalent substituted or unsubstituted hydrocarbon group. And k represents a number of 4 to 1000. ) And / or the following general formula (V)

[0019]

Embedded image (Wherein, R ⁵ represents the same or different monovalent substituted or unsubstituted hydrocarbon group, and 1 represents a number of 4 to 1,000). And [2] the following general formula (VI)

[0020]

Embedded image (In the formula, R ⁶ represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ^{7 to} R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon group, and m represents 4 to 1000.
Represents the number of And / or the linear polysiloxane represented by
Or the following general formula (VII)

[0021]

Embedded image (Wherein, R ¹¹ and R ¹² represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, and n represents a number of 4 to 1,000). The following general formula (VIII) is obtained by heating a polysiloxane component in the presence or absence of a catalyst.

[0022]

Embedded image (Wherein, R ⁴ , R ⁵ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² represent the same or different monovalent substituted or unsubstituted hydrocarbon groups,
p, q, r, and s are numbers from 0 to 9, and p, q, r,
s represents a number that satisfies 3 ≦ p + q + r + s ≦ 10, 1 ≦ p + q, and 1 ≦ r + s. A method for producing a cyclic oligosiloxane represented by the formula (IV), wherein the reaction is monitored by the refractive index of the reaction solution (Claim 8).

[0023]

Embedded image (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ represents a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ⁴ represents a monovalent substituted or unsubstituted hydrocarbon group. And k represents a number of 4 to 1000. ) And a linear polysiloxane represented by the following general formula (VI)

[0024]

Embedded image (In the formula, R ⁶ represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ^{7 to} R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon group, and m represents 4 to 1000.
Represents the number of ) And a chain polysiloxane represented by the following general formula (IX) by heating in the presence or absence of a catalyst.

[0025]

Embedded image (Wherein, R ⁴ , R ⁹ and R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, p and r are numbers from 1 to 9, and p and r are 3 ≦ 10. A method for producing a cyclic oligosiloxane represented by the formula: (p + r ≦ 10), wherein the reaction is monitored by the refractive index of the reaction solution. ), Wherein R ¹ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ ,
^10. The cyclic oligo according to claim 8, wherein R ¹⁰ , R ¹¹ and R ¹² are a methyl group, R ² and R ⁶ are a hydroxyl group or a methyl group, and R ³ is a hydrogen atom or a methyl group. The method for producing a cyclic oligosiloxane according to any one of claims 1 to 10, which is a method for producing a siloxane (claim 10), wherein the catalyst is a metal alkoxide. The method for producing a cyclic oligosiloxane according to any one of claims 1 to 11, wherein the cyclic oligosiloxane to be produced is distilled off, wherein the end point of the reaction is determined by the refractive index of the reaction solution. The method for producing a cyclic oligosiloxane according to any one of claims 1 to 12, wherein the method is determined (claim 13).

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The chain represented by the general formula R ¹ a chain polysiloxane represented by the formula (I), the general formula (IV) in a chain-like polysiloxane of R ¹ and the general formula represented (VI) R ⁷ and R ⁸ of the linear polysiloxane are a monovalent substituted or unsubstituted hydrocarbon group, and examples of the hydrocarbon group include a halogenated alkyl group, an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, Alternatively, an aryl group and the like can be mentioned. Of these, methyl, ethyl, propyl, isopropyl, n-butyl, s-
Examples thereof include a butyl group, a t-butyl group, a cyclohexyl group, a vinyl group and a phenyl group, and more preferably a methyl group and a phenyl group. Most preferred is a methyl group.

The chain represented by the general formula chain polysiloxanes R ² represented by the formula (I), the general formula (IV) in a chain-like polysiloxane of R ² and the general formula represented (VI) R ⁶ of the polysiloxane is a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, and examples of the monovalent substituted or unsubstituted hydrocarbon group are the same as those of R ¹ .

[0029] The general formula (I) represented by chain polysiloxanes of R ³ and the formula of the linear polysiloxane represented by (IV) R ³ is substituted or unsubstituted hydrogen atom or a monovalent a hydrocarbon group, examples of the substituted or unsubstituted monovalent hydrocarbon group are the same as the R ^1.

The linear polysilo represented by the above general formula (I)
Kisane's R^Four, R⁶And the cyclic poly represented by the general formula (II)
R of siloxane^Four, R⁶Represented by the general formula (III)
R of cyclic oligosiloxane^Four, R⁶And the general formula (IV)
R of the linear oligosiloxane represented by^Four, The general formula
R of the cyclic polysiloxane represented by (V)^Five, The general formula
Chain polysiloxane R represented by (VI)⁹, The general formula
R of the cyclic polysiloxane represented by (VII)¹¹The said one
R of the cyclic oligosiloxane represented by the general formula (VIII) ^Four,
R^Five, R⁹, R¹¹And a ring represented by the general formula (IX)
Oligosiloxane R^Four, R⁹Is monovalent substituted or unsubstituted
And an example is the aforementioned R.¹Is the same as Ma
In addition, R in the above general formulas (I), (II) and (III)^Four, R⁶And
And the aforementioned general formulas (IV), (V), (VI), (VII), (VII
R of (I), (IX)^Four, R^Five, R⁹, R¹¹Is repeated for each
The units may be the same or different.

The chain polysilyl represented by the above general formula (I)
Kisane's R^FiveA cyclic policy represented by the general formula (II)
Roxan's R^FiveAnd a ring represented by the general formula (III)
R of linear oligosiloxane^FiveRepresented by the general formula (VI)
R of the chain polysiloxane^TenRepresented by the general formula (VII)
Of the cyclic polysiloxane to be¹²And the general formula (VIII)
R of the cyclic oligosiloxane represented by^Ten, R¹²And before
R of the cyclic oligosiloxane represented by the general formula (IX)^Ten
Is a monovalent substituted or unsubstituted hydrocarbon group;
Examples of elementary groups include alkyl groups, cycloalkyl groups,
Kenyl group, cycloalkenyl group, aryl group, etc.
Is mentioned. Of these, a methyl group and an ethyl group are preferred.
Group, CH_TwoCH_TwoX¹A substituted alkyl group represented by
X for¹Represents a halogen atom, a cyano group, a phenyl group,
Lucoxy group, alkylcarbonyl group, alkoxycarbo
Represents a monovalent organic group such as a nyl group. ), CH_TwoCH (C
H_Three) X^TwoA substituted alkyl group represented by the formula (X^TwoIs
Halogen atom, phenyl group, alkylcarbonyl group,
Represents a monovalent organic group such as a lucoxycarbonyl group. ), C
H _TwoCH_TwoCH_TwoX^ThreeA substituted alkyl group represented by
U X^ThreeIs a halogen atom, a hydroxyl group, a substituted or unsubstituted
Represents a monovalent organic group such as an alkoxy group. ), Vinyl group,
A phenyl group. Further, the above-mentioned general formulas (I) and (I
R of I) and (III)^FiveAnd the general formulas (VI), (VII),
R of (VIII) and (IX)^Ten, R¹²Is a repeating unit
Each may be the same or different.

The linear polysilo represented by the general formula (I)
Specific examples of the xane include Me_ThreeSiO- (Me_ThreeSi
O)_x-SiMe_Three, Me_ThreeSiO- (Ph_TwoSiO)_x−
SiMe_Three, Me_ThreeSiO- (MePhSiO)_x-Si
Me_Three, Me_TwoPhSiO- (Me_TwoSiO)_x-SiMe
_TwoPh, MePh_TwoSiO- (Me_TwoSiO)_x-SiMe
Ph_Two, Me_TwoSi (OH) O- (Me_TwoSiO)_x-Si
Me_Two(OH), Me_ThreeSiO- (MeHSiO)_x-S
iMe_Three, Me_TwoPhSiO- (MeHSiO)_x-Si
Me_TwoPh, MeHSi (OH) O- (MeHSiO)_x
-SiMe (OH) H, where x is 4 to 1000
, Preferably a number from 20 to 500, furthermore
Preferably represents a number of 35 to 200. ) Me_ThreeSiO- (MeSi (CH_TwoCH_TwoC₆H_FourCH_Three)
O)_Five-(MeHSiO)_Five-SiMe_Three, MeHSi
(OH) O- (MeSi (CH_TwoCH_TwoC₆H_FourCH_Three)
O)_Five-(MeHSiO)_Five-SiMe (OH) H, Me
_ThreeSiO- (Me_TwoSiO) _x-(MeHSiO)_y-Si
Me_Three, Me_ThreeSiO- (MePhSiO)_x− (MeH
SiO)_y-SiMe_Three, Me_ThreeSiO- (MeSi (C
H_TwoCH (CH_Three) C₆H_Five) O)_x-(MeHSiO)_y−
SiMe_Three, Me_ThreeSiO- (MeSi (CH_TwoCH_TwoCH
_Two(OCH_TwoCH_Two)_nOMe) O)_x-(MeHSiO)_y−
SiMe_Three, (Where x and y are numbers from 4 to 1000
Preferably, x + y represents a number from 20 to 500,
More preferably, x + y represents a number from 35 to 200,
Here, n represents 0 or a number from 1 to 100.
It preferably represents a number of 1 to 20, more preferably 5 to 1
Represents the number 0. ) And the like.

Examples of the cyclic polysiloxane represented by the general formula (II) include:

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image (Here, x and y represent 0 or a number of 1 to 1000, preferably x + y represents a number of 4 to 100, more preferably x + y represents a number of 4 to 10, and n referred to here is Represents a number of 0 or 1 to 100, preferably 1
-20, more preferably 5-10. ) And the like.

Examples of the cyclic oligosiloxane represented by the general formula (III) include:

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image (Here, x and y represent 0 or a number of 1 to 10, and x
+ Y represents a number of 3 to 10. Preferably, x and y represent 0 or a number of 1 to 6, and x + y represents a number of 3 to 6. More preferably, x and y represent 0 or a number of 1 to 4, and x + y
Is 4. N is 0 or 1 to 100.
, Preferably 1 to 20, more preferably 5 to 10. ) And the like.

The chain polysilyl represented by the general formula (IV)
Specific examples of the xane include Me_ThreeSiO- (MeHSi
O)_x-SiMe_Three, Me_TwoPhSiO- (MeHSi
O)_x-SiMe_TwoPh, MeHSi (OH) O- (Me
HSiO)_x-SiMe (OH) H, Me_ThreeSiO- (P
hHSiO)_x-SiMe_Three, Me_TwoPhSiO- (Ph
HSiO)_x-SiMe_TwoPh, MeHSi (OH) O-
(PhHSiO) _x-SiMe (OH) H, where
X represents a number of 4 to 1000, preferably 20 to 50.
0, more preferably 35 to 200
You. ) And the like.

Examples of the cyclic polysiloxane represented by the general formula (V) include:

[0043]

Embedded image

[0044]

Embedded image (Here, x represents a number of 4 to 1000, preferably represents a number of 4 to 100, and more preferably represents a number of 4 to 10).

Examples of the linear polysiloxane represented by the general formula (VI) include Me ₃ SiO— (Me ₂ SiO) _x
—SiMe ₃ , Me ₃ SiO— (Ph ₂ SiO) _x —SiM
_{e 3, Me3SiO- (MePhSiO) x} -SiMe 3,
Me ₂ PhSiO— (Me ₂ SiO) _x —SiMe ₂ Ph,
MePh ₂ SiO— (Me ₂ SiO) _x —SiMePh ₂ ,
_{Me 2 Si (OH) O- (} Me 2 SiO) x -SiMe
_{2 (OH), Me 3 SiO-} (MeSi (CH 2 CH 2 CH
_{2 (OCH 2 CH 2) n} OMe) O) x -SiMe 3 (x here represents the number of 4 to 1000, preferably a number from 20 to 500, more preferably from 35 to 20
Represents the number of 0, and n is 0 or 1 to 10
It represents the number of 0, preferably represents the number of 1 to 20, more preferably represents the number of 5 to 10. ) And the like.

Specific examples of the cyclic polysiloxane represented by the general formula (VII) include:

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image (Here, x represents a number of 4 to 1,000, preferably represents a number of 4 to 100, more preferably represents a number of 4 to 10, and n represents 0 or a number of 1 to 100. And preferably represents a number of 1 to 20, and more preferably represents a number of 5 to 10).

The general formula (VIII) and the general formula (I
Examples of the cyclic oligosiloxane represented by X) include:

[0052]

Embedded image

[0053]

Embedded image (Where x and y represent numbers from 1 to 9 and x + y is from 3 to
Represents the number 10. Preferably, x and y represent a number of 1 to 5, and x + y represents a number of 3 to 6. More preferably x, y
Represents the number of 1 to 3d, and x + y is 4. In addition, n represents 0 or a number of 1 to 100, preferably a number of 1 to 20, and more preferably a number of 5 to 10. ) And the like.

In the present invention, a catalyst may be used.
Examples of the catalyst used include acid catalysts such as sulfuric acid, hydrochloric acid, alkylsulfonic acid, aluminum halides, acid halides, activated clay, cation exchange resins, alkali metal hydroxides, alkaline earth metal hydroxides, and alkalis. Metal silanolates, alkali metal carbonates, ammonium hydroxide,
Examples include alkaline catalysts such as phosphonium hydroxide, alkali metal fluorides, and neutral catalysts such as metal alkoxides and those obtained by partially hydrolyzing and gelling metal alkoxides. Among these, metal alkoxides are preferred in that the gelation of the reaction system hardly proceeds.

As the metal alkoxide, for example, the following general formula (X)

[0056]

Embedded image (In the formula, R ¹ is a monovalent substituted or unsubstituted hydrocarbon group. Examples of the hydrocarbon group are the same as R ¹ in the above general formula (I), and Y ¹ and Y ² have the same number of carbon atoms. 1 to 8 alkyl groups, aryl groups or alkoxy groups, M is a divalent to tetravalent metal element, and r and s are 0, 1, 2,
3, 4 and r + s is 2 to 4). Of these, metal alkoxides in which M is Al, Ti, Zr, Sn, and Zn are preferably used, and more preferably M is Al, Ti, and Z.
A metal alkoxide of r is used, and most preferably, an aluminum alkoxide is used.

To be more specific, aluminum triethoxide, aluminum triisopropoxide, aluminum tributoxide, aluminum tributoxide, aluminum diisopropoxy second butoxide, aluminum diisopropoxy acetylacetonate, aluminum diethanol Butoxyacetylacetonate, aluminum diisopropoxyethylacetoacetate, aluminum disecondary butoxyethylacetoacetate, aluminum trisacetylacetonate, aluminum trisethylacetoacetate, aluminum acetylacetonate bisethylacetoacetate, titanium tetraethoxy , Titanium tetraisopropoxide, titanium tetrabutoxide, titanium diisopropoxybisacetylacetonate, Tanji isopropoxybis ethyl acetoacetate, titanium tetra 2-ethylhexyl oxide, titanium diisopropoxy bis (2-ethyl-1,
3-hexanediolate), titanium dibutoxy bis (triethanol aminate), zirconium tetrabutoxide, zirconium tetraisopropoxide, zirconium tetramethoxide, zirconium tributoxide monoacetylacetonate, zirconium dibutoxide bisacetylacetonate, zirconium Butoxide trisacetylacetonate, zirconium tetraacetylacetonate, zirconium tributoxide monoethylacetoacetate, zirconium dibutoxide bisethylacetoacetate, zirconium butoxide trisethylacetoacetate, zirconium tetraethylacetoacetate, dibutyltin diacetate, dibutyltin diacetate Octoate, dibutyltin dilaurate, dibutyltin bisacetyl Acetonate, dibutyltin bisethylacetoacetate, tin (II) diacetate, tin (II) dioctoate, tin (II) dilaurate, tin (II) bisacetylacetonate, tin (II) bisethylacetoacetate, zinc diacetate, magnesium Diacetate, magnesium dimethoxide, magnesium diethoxide and the like. In addition, annular 1, 3, 5-
Triisopropoxycyclotrialuminoxane and the like can also be used. Of these, aluminum triisopropoxide, aluminum trisecondary butoxide, aluminum diisopropoxyethyl acetoacetate, aluminum disecondary butoxyethyl acetoacetate, aluminum trisacetylacetonate, titanium tetraisopropoxide, and titanium tetraisopropoxide Butoxide and zirconium tetrabutoxide are used. Most preferred is aluminum triisopropoxide.

These catalysts may be used alone or in any combination.

Further, a catalyst supported on a simple substance such as silica gel, alumina, titania, zeolite, molecular sieve, graphite, metal, glass, or the like by a method such as fusion, vapor deposition, or adsorption can also be used.

The amount of the catalyst used in the present invention can be variously selected according to the reaction rate, but is generally 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on the raw material polysiloxane.
Parts by weight, more preferably 0.01 to 1 part by weight can be used. When a metal alkoxide is supported or partially hydrolyzed, the metal alkoxide is used in an amount of from 0.01 to
10 parts by weight, preferably 0.01 to 5 parts by weight, more preferably 0.01 to 1 part by weight can be used.

The reaction temperature in the present invention may be any temperature at which the reaction proceeds. Generally, a temperature of 60 to 300 ° C. is used. In order to suppress a side reaction and promote the reaction efficiently, the reaction temperature is 100 to 200 ° C. Is preferred. Also,
In order to further suppress the gelation of the reaction, a temperature of 140 to 190C is more preferable.

The reaction of the present invention can be carried out under normal pressure or reduced pressure. However, it is preferable to carry out the reaction under reduced pressure in order to proceed with the reaction efficiently at a relatively low temperature by sequentially distilling the product. . In this case, the reaction can be performed under reduced pressure of, for example, 10 to 300 mmHg.

In the reaction of the present invention, an appropriate solvent or additive can be used according to the purpose of further suppressing gelation. As the solvent, a solvent having no chemical reactivity with the catalyst or the hydrosilyl group or the like and having a higher boiling point than the cyclic oligosiloxane to be produced can be used. Specific examples of the solvent include nonane, decane, dodecane, octadecane, aliphatic saturated hydrocarbons such as decahydronaphthalene, decene, decadiene, aliphatic unsaturated hydrocarbons such as dipentene, mesitylene, diethylbenzene, cumene,
Diphenyl, tetrahydronaphthalene, diphenylbenzene (and its hydride), 2,2'-dimethylbibenzyl, aromatic hydrocarbons such as cyclohexylbenzene, oils such as mineral oil, halogenated hydrocarbons such as dichlorobenzene, Examples thereof include ethers such as diphenyl ether, diethylene glycol diethyl ether and diethylene glycol dibutyl ether, and ketones such as acetophenone. These solvents may be used alone or in a mixture.

Among them, those having compatibility with the raw materials are preferable from the viewpoint of high gelling suppressing effect.

The amount of the solvent used is not particularly limited, but is, for example, 10 to 200 parts by weight, more preferably 50 to 100 parts by weight, based on the amount of the raw material.

The used solvent can be recovered by distillation after the completion of the reaction and reused.

As an additive, disiloxane or trisiloxane can be used. As a specific example,
Hexaethyldisiloxane, 1,3-diphenyl-1,1,3,3-
Tetramethyldisiloxane, 1,1,1,3,5,5,5-heptamethyltrisiloxane, octamethyltrisiloxane, 1,3,
3,5-tetramethyl-1,1,5,5-tetraphenyltrisiloxane and the like. These disiloxanes or trisiloxanes may be used alone or as a mixture.

The amount of disiloxane or trisiloxane used is not particularly limited, but is, for example, 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on the raw material.

[0069] Alcohols can also be used as additives. Specific examples include aliphatic alcohols such as hexanol, octanol, 2-ethylhexyl alcohol, lauryl alcohol, stearyl alcohol, and cyclohexyl alcohol, and aromatic alcohols such as benzyl alcohol, phenethyl alcohol, and 3-phenyl-1-propanol. Is mentioned. These alcohols may be used alone or in a mixture.

The amount of the alcohol to be used is not particularly limited, but for example, 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on the raw material.

Other carboxylic acid esters or orthoesters of alcohol can also be used as additives. Specific examples include esters or orthoesters of alcohols exemplified as the alcohols that can be used as the additive, such as formic acid, acetic acid, propionic acid, and benzoic acid. These carboxylic esters or orthoesters may be used alone or as a mixture.

The amount of the carboxylic acid ester or orthoester used is not particularly limited, but may be, for example, 0.1 to 20 parts by weight, more preferably 0.1 to 20 parts by weight, based on the raw material.
5 to 10 parts by weight are used.

The above-mentioned solvent or additive is preferably one having a boiling point higher than that of the cyclic oligosiloxane to be obtained by the reaction in order to make the reaction proceed efficiently. Those having a boiling point higher by 10 ° C. or more at normal pressure than the boiling point of the oligosiloxane are more preferred.

The solvent or additive may be added in its entirety before or from the start of the reaction. However, in order to improve the efficiency of the reaction, part or all of the solvent used is successively added during the reaction. Alternatively, they may be added all at once.

The present invention can be practiced even when a small amount of alkoxysilane is present as an additive other than the solvent, but the greater the amount of alkoxysilane added, the lower the yield of the target cyclosiloxane, and therefore, the practicality is reduced. Tends to be lower.

The reaction of the present invention can be carried out by mixing and heating the starting polysiloxane and, if necessary, the catalyst, and then purifying the product by distillation or the like. Can also be performed. In order to suppress a side reaction, it is desirable to carry out the reaction while sequentially distilling out the product. When distilling off the product, a rectification column such as various packed columns can be used as necessary. When a rectification column is used, the purity of the product can be increased.

Further, a semi-continuous method in which the raw material polysiloxane is added to the reaction residue obtained by distilling off a part of the generated cyclic oligosiloxane and the reaction is further continued, or the generated cyclic oligosiloxane is distilled off The production can also be carried out by a semi-continuous or continuous method in which the reaction is carried out while simultaneously adding the starting material and the polysiloxane as a raw material.

Further, when a catalyst which is solid under the reaction conditions of the present invention is used, the production can also be carried out by a continuous method, for example, by passing the raw material through a reactor filled with the catalyst and heated. .

In the reaction of the present invention, a low-molecular-weight cyclic oligosiloxane can be produced from a high-molecular-weight chain or cyclic polysiloxane, but conversely, a low-molecular-weight cyclic oligosiloxane can be converted into a high-molecular-weight substance. .

In the present invention, the reaction is monitored by the refractive index of the reaction solution. The refractive index of the reaction solution gradually changes with the progress of the reaction, and when the reaction solution reaches a certain value determined by the reaction conditions and the like, the reaction solution gels. Therefore, by monitoring the reaction based on the refractive index of the reaction solution, the reaction can be terminated immediately before the reaction solution gels.

As the means for measuring the refractive index used at this time, various methods generally used can be used. For example, a general refractometer can be used, and a detector for liquid chromatography or the like can be used. An online type refractometer used for the above method can also be used. From the viewpoint that the reaction can be constantly monitored, it is preferable to use an online refractometer.

As a monitoring method, the monitoring may be performed at all times as described above, but it is also possible to monitor by sampling and measuring the reaction solution each time. In this case, the sampling interval can be set arbitrarily. For example, sampling can be performed at a relatively long interval at the beginning of the reaction, and the sampling interval can be shortened as the refractive index changes.

The end point of the reaction can be determined by the refractive index of the reaction solution. However, in view of increasing the yield of the reaction, the end point of the reaction is determined by the point at which the refractive index of the reaction solution gels. Is preferably set immediately before the refractive index. Specifically, for example, the following formula (XI): γ = α + ε (β−α) (XI) (α represents the refractive index of the reaction solution at the start of the reaction, and β represents the reaction solution at the time when the reaction solution gels. Represents the refractive index, γ represents the refractive index of the reaction solution at the end point of the reaction, and ε represents 0 <ε <
Represents any coefficient that satisfies 1. ), Γ
Can be the refractive index of the reaction solution at the end point of the reaction.
At this time, in order to increase the yield of the reaction,
The above value is preferable, the value of 0.5 or more is more preferable,
A value of 0.7 or more is more preferable. Further, from the viewpoint that the gelation of the reaction solution can be stably avoided, ε is set to 0.1.
A value of 99 or less is preferred, a value of 0.9 or less is more preferred, and a value of 0.8 or less is even more preferred. Overall, ε is 0.3 to 0.99, more preferably 0.5 to 0.8.
Is used.

The refractive index of the reaction solution may gradually decrease from the start of the reaction, reach a minimum value, and then increase again. Then, this minimum refractive index is defined as α ′, for example, the following formula (XII) γ = α ′ + ε (β−α ′) (XII) (α ′ is the lowest value of the refractive index of the reaction solution during the course of the reaction. Represents the refractive index of the reaction solution at the time when the reaction solution gels, γ represents the refractive index of the reaction solution at the end point of the reaction, and ε represents an arbitrary coefficient satisfying 0 <ε <1. Express.)
Γ, which is represented by the following formula, may be used as the refractive index of the reaction solution at the end point of the reaction. At this time, in order to increase the reaction yield, ε is preferably a value of 0.5 or more, more preferably 0.65 or more, and even more preferably 0.7 or more.
Further, from the viewpoint that gelation of the reaction solution can be stably avoided, a value of 0.99 or less is preferable as ε, a value of 0.9 or less is more preferable, and a value of 0.8 or less is further preferable. In general, a value of 0.5 to 0.99, more preferably 0.65 to 0.9 is used for ε.

In particular, Me ₃ SiO— (MeHSiO) ₄₀
When a product containing 1,3,5,7-tetramethylcyclotetrasiloxane as a main component is produced using a metal alkoxide catalyst by using trimethylsilyl polymethyl hydrogen siloxane represented by both ends represented by —SiMe ₃ as a raw material. Generally indicates that the refractive index of the reaction solution gradually decreases from the start of the reaction, reaches a minimum value, and then increases again. It is known that the reaction liquid gels when the refractive index increases by about 0.003 from the minimum value of the refractive index. Therefore, the refractive index of the reaction liquid decreases from the minimum value to, for example, 0.001.
To any value in the range of 0.0025 to 0.0025, preferably 0.
The time point at which the value increases by an arbitrary value in the range of 002 to 0.0025 can be set as the end point of the reaction.

After the refractive index has reached the reaction end point, the reaction can be stopped by any method. For example, methods such as stopping heating, cooling, repressurizing the reaction system, pressurizing, stopping the distillation of the product, refluxing the product to the reactor, charging a solvent or raw material, charging a catalyst deactivator, and the like are selected. it can.

Next, the present invention will be described specifically with reference to examples. However, the present invention is not limited to the following examples.

[0088]

Reference Example 1 In a 100 mL two-necked flask equipped with a condenser and a magnetic stirrer, Me ₃ SiO— (MeHSiO) ₄₀ —SiM was added.
Put both ends trimethylsilyl polymethyl hydrogen siloxane 75g represented by e _3, after the addition of aluminum triisopropoxide 0.75 g, it was stirred with heating to 200 ° C. under nitrogen. The reaction solution is sampled over time and a refractometer (ATAGO, precision Abbe refractometer 3T) is used.
Was used to measure the refractive index at 23 ° C.

At the start of the reaction, the refractive index was 1.3965, but it rose with time, and the reaction solution gelled. The refractive index at the time of gelation was 1.3988 when extrapolated from the relationship between the reaction time and the refractive index. Reference Example 2 The same operation as in Reference Example 1 was performed except that 1.5 g of aluminum triisopropoxide was added.

At the start of the reaction, the refractive index was 1.3965, but it rose with time, and the reaction solution gelled. The refractive index at the time of gelation was 1.3988 when extrapolated from the relationship between the reaction time and the refractive index. Reference Example 3 The same operation as in Reference Example 1 was performed except that the reaction temperature was 170 ° C.

At the start of the reaction, the refractive index was 1.3965, but it rose with time, and the reaction solution gelled. The refractive index at the time of gelation was 1.3987 when extrapolated from the relationship between the reaction time and the refractive index. Reference Example 4 The same operation as in Reference Example 2 was performed except that the reaction temperature was 170 ° C.

At the start of the reaction, the refractive index was 1.3965, but it rose with time, and the reaction solution gelled. The refractive index at the time of gelation was 1.3988 when extrapolated from the relationship between the reaction time and the refractive index. Example 1 Thermometer, magnetic stirrer, rectification column (filled with McMahon, 30c
m) equipped with a distillate tube with distillate and a distillate collector
A 0 mL 4-neck round bottom flask was connected to a vacuum pump through a trap. Me ₃ SiO- (MeH
Both ends trimethylsilyl polymethyl siloxane 150g represented by SiO) ₄₀ -SiMe _3, and was placed in an aluminum triisopropoxide 0.3 g. Subsequently, while heating the flask in an oil bath at 170 to 180 ° C., the system was maintained at a reduced pressure of 50 mmHg, and a reflux ratio of 1
The distillate distilled under the condition of was collected. The obtained fraction was analyzed by gas chromatography to find that it was 1,3,5,7.
-A mixture containing tetramethylcyclotetrasiloxane as a main component.

At this time, the reaction solution was sampled with time, and the refractive index at 23 ° C. was measured with a refractometer (ATAGO, precision Abbe refractometer 3T). At the start of the reaction, the refractive index was 1.3970, but it decreased with time and reached a minimum value of 1.3.
After showing 3963, it rose again and when it reached 1.3955, the reaction solution gelled. Example 2 The same operation as in Example 1 was performed, and the refractive index of the reaction solution was 1.
When it reached 3985, the reaction was completed. The reaction solution did not gel even after the reaction was stopped. At this time, the yield of the reaction was 90%. Example 3 A 30-L reactor equipped with a heating medium circulation jacket equipped with a stirrer, a rectification column (filled with McMahon, 100 cm), a reflux ratio setting facility, and a distillate collector was connected to a vacuum pump through a trap. Me ₃ SiO- (MeHS
iO) ₄₀ -SiMe ₃ both terminals represented by trimethylsilyl polymethyl siloxane 28 kg, and was charged with aluminum triisopropoxide 28 g.
Subsequently, the system was maintained at a reduced pressure of 50 mmHg, and a heating medium heated to 170 ° C. was circulated through the jacket, and a fraction distilled at a reflux ratio of 2 was recovered while heating. The obtained fraction was analyzed by gas chromatography to find that it was 1,3,3.
It was a mixture containing 5,7-tetramethylcyclotetrasiloxane as a main component.

At this time, the reaction solution was sampled with time, and the refractive index at 23 ° C. was measured by a refractometer (ATAGO, precision Abbe refractometer 3T). At the start of the reaction, the refractive index was 1.3970, but it decreased with time and reached a minimum value of 1.3.
After showing 3958, it increased again, and the refractive index of the reaction solution was 1.
The reaction was completed when the reaction reached 3980. The reaction solution did not gel even after the reaction was stopped. At this time, the yield of the reaction was 91%.

[0095]

According to the present invention, it is possible to provide a practical method for producing a cyclic oligosiloxane capable of monitoring the reaction by the refractive index and terminating the reaction immediately before the reaction solution gels.

Continued on front page F-term (reference) 4H039 CA42 CH10 CH90 4H049 VN01 VP04 VP10 VQ02 VQ78 VR21 VR22 VR42 VS21 VS22 VS23 VS42 VT08 VT08 VT09 VT30 VU36 VW02 VW05 4J035 BA02 CA02U CA021 CA05U CA052 FB06 H05B

Claims (14)

[Claims] 1. A method for producing a cyclic oligosiloxane by heating a linear or cyclic polysiloxane, wherein the reaction is monitored by the refractive index of a reaction solution. 2. A compound represented by the following general formula (I): (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² is a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ is a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ^{4 to} R ⁶ are the same or different monovalent substituted or Represents an unsubstituted hydrocarbon group, k and l are each independently 0 or a number from 1 to 1000, and k and l represent numbers satisfying 4 ≦ k + 1 ≦ 1000. And / or the following general formula (II): (Wherein, R ^{4 to} R ⁶ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, m and n are each independently 0 or a number from 1 to 1000, and m and n
Represents a number satisfying 3 ≦ m + n ≦ 1000. ) By heating a cyclic polysiloxane represented by the following general formula (III): (Wherein, R ^{4 to} R ⁶ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, p and q each independently represent a number of 0 or 1 to 10, and p and q represent 3
≤p + q≤10. A method for producing a cyclic oligosiloxane represented by the formula (1), wherein the reaction is monitored by the refractive index of the reaction solution. 3. k and m are each independently 0 or a number from 1 to 999; l and n are each independently a number from 1 to 1000; and p is 0 or 1 to 9 The method for producing a cyclic oligosiloxane according to claim 2, wherein q is a number of 1 to 10. 4. The apparatus according to claim 1, wherein said k, l, m, n, p, and q are 5 ≦ m + n.
The method for producing a cyclic oligosiloxane according to claim 3, wherein the number satisfies ≦ 1000 and p + q <k + 1 and p + q <m + n. 5. The method according to claim ² , wherein R ¹ , R ⁴ and R ⁶ are a methyl group, R ² is a hydroxyl group or a methyl group, and R ³ is a hydrogen atom or a methyl group. The method for producing a cyclic oligosiloxane of the above. 6. The cyclic oligosiloxane according to claim 2, wherein k, l, m, n, p and q satisfy k <l, m <n and p <q. Production method. 7. The method for producing a cyclic oligosiloxane according to claim 3, wherein k = m = p = 0. [1] [1] The following general formula (IV): (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ represents a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ⁴ represents a monovalent substituted or unsubstituted hydrocarbon group. And k represents a number of 4 to 1000. And / or the following general formula (V): (Wherein, R ⁵ represents the same or different monovalent substituted or unsubstituted hydrocarbon group, and 1 represents a number of 4 to 1,000). And [2] the following general formula (VI): (In the formula, R ⁶ represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ^{7 to} R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon group, and m represents 4 to 1000.
Represents the number of And / or the linear polysiloxane represented by
Or the following general formula (VII): (Wherein, R ¹¹ and R ¹² represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, and n represents a number of 4 to 1,000). By heating the polysiloxane component, the following general formula (VIII): (Wherein, R ⁴ , R ⁵ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² represent the same or different monovalent substituted or unsubstituted hydrocarbon groups,
p, q, r, and s are numbers from 0 to 9, and p, q, r,
s represents a number that satisfies 3 ≦ p + q + r + s ≦ 10, 1 ≦ p + q, and 1 ≦ r + s. A method for producing a cyclic oligosiloxane represented by the formula (1), wherein the reaction is monitored by the refractive index of the reaction solution. 9. A compound represented by the following general formula (IV): (Wherein R ¹ is a monovalent substituted or unsubstituted hydrocarbon group,
R ² represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ³ represents a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group, and R ⁴ represents a monovalent substituted or unsubstituted hydrocarbon group. And k represents a number of 4 to 1000. A) a chain polysiloxane represented by the following general formula (VI): (In the formula, R ⁶ represents a hydroxyl group or a monovalent substituted or unsubstituted hydrocarbon group, R ^{7 to} R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon group, and m represents 4 to 1000.
Represents the number of ) By heating a linear polysiloxane represented by the following general formula (IX): (Wherein, R ⁴ , R ⁹ and R ¹⁰ represent the same or different monovalent substituted or unsubstituted hydrocarbon groups, p and r are numbers from 1 to 9, and p and r are 3 ≦ a method that satisfies p + r ≦ 10), wherein the reaction is monitored by the refractive index of the reaction solution. 10. The R ¹ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R
^10, R ^11, R ¹² is a methyl group, R ^2, R ⁶ is hydroxyl group or a methyl group, R ³ is claim is a hydrogen atom or a methyl group 8
Alternatively, a method for producing the cyclic oligosiloxane according to claim 9. 11. The method for producing a cyclic oligosiloxane according to claim 1, wherein the catalyst is a metal alkoxide. 12. The method for producing a cyclic oligosiloxane according to claim 1, wherein the cyclic oligosiloxane produced under reduced pressure is distilled off. 13. The method for producing a cyclic oligosiloxane according to claim 1, wherein the end point of the reaction is determined by the refractive index of the reaction solution. 14. The method for producing a cyclic oligosiloxane according to claim 1, wherein the heating is carried out in the presence of a catalyst.