JP2005187381A - Method for refining silicon compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refining method for obtaining a high-purity polyhedral oligosilsesquioxane in high yield by effectively separating and removing an alkali metal compound by a simple operation. <P>SOLUTION: The refining method comprises the following practice: A composition comprising a polyhedral oligosilsesquioxane and an alkali metal compound is contacted with a hydrophobic organic solvent to dissolve the polyhedral oligosilsesquioxane in the hydrophobic organic solvent followed by treating the resultant solution with a hydrophobic membrane filter or the like. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a method for purifying polyhedral oligosilsesquioxane and a method for producing high-purity polyhedral oligosilsesquioxane using this purification method. More specifically, the present invention relates to a method for purifying a partially cleaved structure of a cage silsesquioxane having a trisilanol structure, and a method for purifying a cage silsesquioxane having a highly pure trisilanol structure using this purification method. The present invention relates to a method for producing a partially cleaved structure.

Polyhedral oligosilsesquioxane is useful as a new type of silicon atom-containing monomer or a preparation raw material thereof (for example, see Non-Patent Document 1). In addition, various polyhedral oligosilsesquioxanes such as cage silsesquioxane and cage silsesquioxane partially cleaved structures are used as additives to simultaneously improve the melt fluidity and flame retardancy of polyphenylene ether resins. It has been reported to be effective. (For example, see Patent Document 1)
Polyhedral oligosilsesquioxanes used for these applications are required to have high purity. In particular, in applications in the field of electronic materials, the content of ionic impurities, particularly alkali metal ions or alkali metal salts, must be extremely low.

Various methods are known as a synthesis method of polyhedral oligosilsesquioxane. For example, as a method for synthesizing an initial cage-like silsesquioxane, a method of decomposing and condensing in methanol using an acid from methyltrichlorosilane has been reported (for example, see Non-Patent Document 2).
As a prior art for synthesizing a caged silsesquioxane partial cleavage structure, cyclohexyltrichlorosilane is hydrolyzed and condensed in acetone to obtain a caged silsesquioxane partial cleavage structure having a trisilanol structure. A method (for example, see Non-Patent Document 3) or a method for hydrolyzing and condensing cyclopentyltrichlorosilane in an acetone solvent (for example, see Non-Patent Document 4) has been reported.

In addition, various polyhedral oligosilsesquioxanes such as rod-shaped silsesquioxanes or partially cleaved structures thereof can be obtained by combining polysilsesquioxane resin, polysilsesquioxane partial fragment structures, etc. with various bases. A method of synthesis by reaction has been reported (for example, see Patent Document 2). Among these various synthesis methods, the synthesis method by reaction with a base described in Patent Document 2 is preferable because the reaction rate is high and the yield is high.
As mentioned above, when polyhedral oligosilsesquioxane is used industrially, a high-purity product having a low content of ionic impurities, particularly alkali metal ions or alkali metal salts, is required. The above document does not describe the content of such ionic impurities or an effective removal method thereof.

For example, Patent Document 2 described above describes, as a typical production method, methods for producing various polyhedral oligosilsesquioxanes by reacting various silicon compounds with basic alkali metal compounds such as alkali metal hydroxides. Has been. In this method, an acid is added to the reaction system as necessary after the reaction to convert the basic alkali metal compound into an alkali metal salt. However, Patent Document 2 does not describe anything about the content of alkali metal compounds in various polyhedral oligosilsesquioxanes obtained by this method.
Therefore, the present inventors have used the method described in Patent Document 2 to form polyhedral oligosilsesquioxanes having various structures such as cage-shaped silsesquioxane and partially-cleaved structures of cage-shaped silsesquioxane having a silanol structure. As a result, only polyhedral oligosilsesquioxane containing a large amount of alkali metal compounds such as alkali metal salts and alkali metal hydroxides could be obtained. In addition, alkali metal compounds mixed in polyhedral oligosilsesquioxanes such as the partially cleaved structure of caged silsesquioxanes or caged silsesquioxanes having silanol structures can be used for recrystallization, sublimation, etc. It was not possible to remove efficiently by the purification methods, and these purification methods could not obtain a high-purity polyhedral oligosilsesquioxane having a low alkali metal compound content.

The reason why it is difficult to remove alkali metal compounds from these polyhedral oligosilsesquioxanes (especially trisilanol group-containing structures) is not clear, but for example, these cage-like siloxane structures, especially silanol group-containing structures and alkali There may be some interaction between the metal ions.
Therefore, when various polyhedral oligosilsesquioxanes are to be used in the field of electronic materials, the development of a purification method for polyhedral oligosilsesquioxanes that economically and effectively removes alkali metal compounds has been developed. is necessary.

J.D.Lichtenhan et.al., Polymer Preprints, 36,511 (1995), ibid 36,513 (1995) K. Olsson, Arkiv Kemi, 13, p. p. 367-378 (1958) Brown & Vogt, J.A. Amer. Chem. Soc. , (1965), 4313 Feher et. al. , Organometallics, 1991, 526 WO02 / 059208 pamphlet International Publication No. 01/010871 Pamphlet

One of the objects of the present invention is to separate and remove an alkali metal compound effectively by a simple operation in producing a polyhedral oligosilsesquioxane using a basic alkali metal compound, and to achieve high yield and high purity. To provide an economically advantageous production method for obtaining polyhedral oligosilsesquioxanes.
Another object of the present invention is to efficiently remove an alkali metal compound from a rough polyhedral oligosilsesquioxane containing an alkali metal compound as an impurity, which is inconvenient for use in the field of highly functional materials such as electronic materials. It is another object of the present invention to provide a purification method for producing a high-quality polyhedral oligosilsesquioxane.

Another object of the present invention is to provide a novel method for producing a polyhedral oligosilsesquioxane including this purification step.
More specifically, the present invention relates to a purification method for separating and removing an alkali metal compound from a partially cleaved structure of caged silsesquioxane having a trisilanol structure, and a kit having a highly pure trisilanol structure including this purification step. An object of the present invention is to provide a method for producing a partially-cleavage structure of silsesquioxane.

As a result of intensive studies to solve the above problems, the present inventors have found an efficient method for purifying polyhedral oligosilsesquioxane using a hydrophobic solvent, and have completed the present invention.
The process will be briefly described below.
First, when the present inventors contact a composition containing at least both a polyhedral oligosilsesquioxane and an alkali metal compound with a hydrophobic organic solvent, the polyhedral oligosilsesquioxane is dissolved and fine particles It has been found that an organic phase containing the dispersion is formed. In addition, when there is much alkali metal compound content in the said composition, the organic phase and precipitation part of a composition similar to the said organic phase are formed.

Since the fine particle dispersion in the organic phase is composed of extremely fine fine particles, the appearance of the organic phase is transparent, but when the present inventors investigated its composition, several hundreds of particles were found in the organic phase. It turned out that the alkali metal compound of ppm or more, or several thousand ppm or more was mixed.
Next, as a result of intensive studies on the method for removing the alkali metal compound from the organic phase, the present inventors have surprisingly found that the fine particles are separated from the organic phase by various separation methods typified by filtration with a hydrophobic membrane filter. When the dispersion was separated, it was found that a high-quality polyhedral oligosilsesquioxane containing almost no alkali metal compound can be obtained very effectively, and the present invention has been completed.

That is, the present invention is as follows.
(1) A method for purifying a polyhedral oligosilsesquioxane represented by the general formula (1) or (2) containing an alkali metal compound,
(RSiO _3/2 ) _n (1)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
(In the general formulas (1) and (2), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and a silicon atom-containing group having 1 to 3 silicon atoms. R may be the same or different. In general formula (2), Xa is a group selected from OH and the group defined by R, and a plurality of Xa may be the same or different. A plurality of Xa in (RXaSiO) _k may be connected to each other to form a connection structure, n is an integer from 6 to 14, l is an integer from 2 to 10, and k is an integer from 2 to 4. Yes, the total number of carbon atoms in general formula (1) is in the range of n to n × 12, and the total number of carbon atoms in general formula (2) is in the range of (l + k) to (l + k) × 12. Within.)
(1) A composition containing both at least a polyhedral oligosilsesquioxane and an alkali metal compound is brought into contact with a hydrophobic organic solvent having a water solubility at 20 ° C. of 1.0% by weight or less to form a hydrophobic organic A step of dissolving polyhedral oligosilsesquioxane in a solvent and obtaining an organic phase containing a fine particle dispersion; and (2) an organic phase containing the polyhedral oligosilsesquioxane obtained in the previous step and the fine particle dispersion. And a step of separating the fine particle dispersion from the polyhedral oligosilsesquioxane.

(2) The method for purifying a polyhedral oligosilsesquioxane according to (1), wherein the step (2) of separating the fine particle dispersion is a filtration treatment step.
(3) The method for purifying a polyhedral oligosilsesquioxane according to (2), wherein the filtration treatment step is a filtration treatment step using a hydrophobic filter.
(4) The method for purifying polyhedral oligosilsesquioxane according to (3), wherein the hydrophobic filter is a hydrophobic membrane filter having an average pore size of 0.005 μm or more and 100 μm or less.
(5) Any one of (1) to (4), wherein the hydrophobic organic solvent used in the step (1) is an organic solvent having a water solubility at 20 ° C. of 0.5% by weight or less. For purification of polyhedral oligosilsesquioxane according to claim 1

(6) The polyhedral oligosilsesquioxane according to any one of (1) to (5), wherein the polyhedral oligosilsesquioxane is a silanol compound represented by the general formula (3) Purification method.
(R ¹ SiO _3/2 ) _l (R ¹ (OH) SiO) _k (3)
(In the general formula (3), R ¹ is selected from a hydrogen atom and a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ¹ may be the same or different, and l is 2 The integer of from 10 to 10 and k is the integer of from 2 to 4, and the total number of carbon atoms in the general formula (3) is in the range of (l + k) to (l + k) × 12.)

(7) The polyhedral oligosilsesquioxane according to (6), wherein the silanol compound represented by the general formula (3) has a structure represented by the general formula (4) or (5) Purification method.
(R ¹ SiO _3/2 ) ₄ (R ¹ (OH) SiO) ₃ (4)

（一般式（４）および（５）中のR^１は、一般式（３）中のR^１と同じであり、一般式
（５）において、同一のケイ素原子に結合しているR^１基とＯＨ基はそれぞれお互いの位置を交換したものでもよい。）

(R ^{1 in} general formulas (4) and (5) is the same as R ¹ in general formula (3). In general formula (5), R ¹ group bonded to the same silicon atom is OH groups may be exchanged for each other.)

(8) The polyhedral oligosilsesquioxy according to any one of (1) to (7), wherein R and R ¹ are groups selected from hydrocarbon groups having 2 to 10 carbon atoms. Sun purification method.
(9) The method for purifying a polyhedral oligosilsesquioxane according to (8), wherein the hydrocarbon group is a branched hydrocarbon group having 3 to 10 carbon atoms.
(10) The method for purifying a polyhedral oligosilsesquioxane according to (9), wherein the branched hydrocarbon group is an isobutyl group.
(11) The polyhedral oligo described in any one of (1) to (10), wherein the composition used in step (1) contains 80% by weight or more of polyhedral oligosilsesquioxane. A method for purifying silsesquioxane.

(12) In the step (1), the aqueous dispersion composition containing at least both the polyhedral oligosilsesquioxane and the alkali metal compound is brought into contact with a hydrophobic organic solvent, and the polyhedral oligosilsesquioxy is brought into contact with the hydrophobic organic solvent. The polyhedral oligosilsesquioxide according to any one of (1) to (10), which is a step of obtaining the organic phase by extracting the sun and then separating the organic phase and the aqueous phase. Sun purification method.
(13) In the purification method of the polyhedral oligosilsesquioxane according to any one of (1) to (12), the solution containing the polyhedral oligosilsesquioxane obtained in step (2) is further added. A method for purifying polyhedral oligosilsesquioxane, wherein a step of precipitating polyhedral oligosilsesquioxane is added by adding a poor solvent for polyhedral oligosilsesquioxane.

(14) A) It is represented by the general formula (1) by reaction with a basic alkali metal compound using at least one silicon compound selected from the compound represented by the general formula (6) and the condensate thereof as a raw material. A step of producing a polyhedral oligosilsesquioxane, and B) a polyhedral oligo represented by the general formula (1) according to any one of (1) to (5) and (8) to (13) A method for producing a high-purity polyhedral oligosilsesquioxane, which is combined with a purification step of silsesquioxane.
RSiXb ₃ (6)
(RSiO _3/2 ) _n (1)
(In General Formula (6), R is the same as defined in General Formula (1), and Xb is a group selected from an OH group, a halogen atom, and an —OQ group (Q is a hydrocarbon group having 1 to 10 carbon atoms). A plurality of Xb may be the same or different, and in general formula (1), R represents a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and the number of silicon atoms; Selected from 1 to 3 silicon atom-containing groups, a plurality of Rs may be the same or different, n is an integer from 6 to 14, and the total number of carbon atoms in general formula (1) is n to n Within the range of x12.)

(15) A ′) represented by the general formula (2) by reaction with a basic alkali metal compound using at least one silicon compound selected from the compound represented by the general formula (6) and the condensate thereof as a raw material. A process for producing a polyhedral oligosilsesquioxane to be produced (provided that, when producing a polyhedral oligosilsesquioxane in which at least one of Xa in the general formula (2) is an OH group, A step of producing a polyhedral oligosilsesquioxane represented by the general formula (2) by applying an acid treatment operation), and B ′) the general formula (1) to the general formula (1) described in any one of the above (1) to (13) ( A method for producing a high-purity polyhedral oligosilsesquioxane, which is combined with a purification step of the polyhedral oligosilsesquioxane represented by 2).
RSiXb ₃ (6)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
(In General Formula (6), R is the same as defined in General Formula (2), and Xb is a group selected from an OH group, a halogen atom, and an —OQ group (Q is a hydrocarbon group having 1 to 10 carbon atoms). A plurality of Xb may be the same or different, and in general formula (2), R is a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and the number of silicon atoms; Selected from 1 to 3 silicon atom-containing groups, a plurality of R may be the same or different, and Xa in the general formula (2) is a group selected from OH and the group defined by R; A plurality of Xa may be the same or different, and a plurality of Xa in (RXaSiO) _k may be connected to each other to form a connection structure, l is an integer of 2 to 10, and k is 2 To an integer from 4 to the total number of carbon atoms in general formula (2) (L + k) ~ (l + k) is in the range of × 12.)

(16) The compound represented by the general formula (6) is the compound represented by the general formula (7), and the polyhedral oligosilsesquioxane to be produced and purified is represented by the general formula (8). The method for producing a high-purity polyhedral oligosilsesquioxane according to (15), which is a silanol compound.
R ² SiXc ₃ (7)
(R ² SiO _3/2 ) _l (R ² (OH) SiO) _k (8)
(R ² in the general formulas (7) and (8) is a hydrocarbon group having 2 to 10 carbon atoms, and a plurality of R ² in the general formula (8) may be the same or different. Xc in C) is an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, Xc may be composed of a plurality of groups selected from these groups, l is an integer of 2 to 10, and k is from 2 It is an integer of 4.)

(17) The high purity polyhedral oligosilsesqui described in (16), wherein the compound represented by the general formula (8) has a structure represented by the general formula (9) or the general formula (10) Oxane production method.
(R ³ SiO _3/2 ) ₄ (R ³ (OH) SiO) ₃ (9)

（一般式（９）および（１０）中のR^３は、一般式（８）中のR^２と同じであり、一般式（１０）において、同一のケイ素原子に結合しているR^３基とＯＨ基はそれぞれお互いの位置を交換したものでもよい。）

(R ^{3 in} general formulas (9) and (10) is the same as R ² in general formula (8). In general formula (10), R ³ group bonded to the same silicon atom and OH groups may be exchanged for each other.)

(18) The method for producing a high-purity polyhedral oligosilsesquioxane according to (17), wherein R ³ is an isobutyl group.
(19) Step A ′) for producing a polyhedral oligosilsesquioxane is a step of reacting A′-1) raw material silicon compound and alkali metal hydroxide in the range of 30 to 300 ° C. in the presence of water. And A′-2) a high purity polyhedral oligosilsesquioxane according to any one of (15) to (18), which comprises a step of treating the reaction mixture produced in the previous step with an acid. Manufacturing method.
(20) The method for producing a high-purity polyhedral oligosilsesquioxane according to (19), wherein the reaction temperature in step A′-1) is 70 to 200 ° C.

(21) The method for producing a high-purity polyhedral oligosilsesquioxane according to (19) or (20), wherein the alkali metal hydroxide used in step A′-1) is lithium hydroxide. .
(22) The acid used in Step A ′) or Step A′-2) is a pKa (logarithm of the reciprocal of acid dissociation constant) in an aqueous solution at 25 ° C. in the range of −2.0 to +5.5. (15)-(21) The manufacturing method of the high purity polyhedral oligosilsesquioxane as described in any one of (15)-(21) characterized by the above-mentioned.
(23) The method for producing a high purity polyhedral oligosilsesquioxane according to (22), wherein the acid is acetic acid

According to the present invention, when a polyhedral oligosilsesquioxane is produced using a basic alkali metal compound, the alkali metal compound is effectively separated and removed by a simple operation, and the polyhedral oligosilsesquioxane having high yield and high purity is obtained. A practical manufacturing method for obtaining sun has become possible.
In addition, the method of the present invention efficiently removes an alkali metal compound from a rough polyhedral oligosilsesquioxane containing an alkali metal compound as an impurity, which is inconvenient for use in the field of highly functional materials such as electronic materials. A purification method for producing a high-quality polyhedral oligosilsesquioxane suitable for use in the field of high-functional materials such as electronic materials has become possible.
More specifically, the method of the present invention has enabled a practical production method of high-purity polyhedral oligosilsesquioxane using this production process or this purification process.

Embodiments of the present invention will be described below.
First, the substance used in the present invention will be described.
a-1) Polyhedral oligosilsesquioxane The polyhedral oligosilsesquioxane in the present invention is a polyhedral oligomeric compound of silsesquioxane or a partial cleavage structure thereof. Silsesquioxane is also called polysilsesquioxane or T-resin, and consists of units represented by [R′SiO _3/2 ], whereas ordinary silica is represented by SiO ₂ units. A compound.
Silsesquioxane is a polysiloxane usually synthesized by hydrolysis-polycondensation of R′SiX ₃ (R ′ = hydrogen atom, organic group, siloxy group, X = halogen atom, alkoxy group) type compound, The shape of the molecular arrangement is typically an amorphous structure, a ladder structure, a cage structure (fully condensed cage structure) or a partially cleaved structure (a structure in which several atoms are missing from the cage structure, or a cage shape A structure in which a silicon-oxygen bond is partially broken) is known.

The molecular arrangement of the polyhedral oligosilsesquioxane in the present embodiment includes a cage silsesquioxane represented by the following general formula (1) and a cage silsesquioxane represented by the general formula (2). It is a partial cleavage structure of oxane.
(RSiO _3/2 ) _n (1)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
(In the general formulas (1) and (2), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and a silicon atom-containing group having 1 to 3 silicon atoms. R may be the same or different. In general formula (2), Xa is a group selected from OH and the group defined by R, and a plurality of Xa may be the same or different. A plurality of Xa in (RXaSiO) _k may be connected to each other to form a connection structure, n is an integer from 6 to 14, l is an integer from 2 to 10, and k is an integer from 2 to 4. Yes, the total number of carbon atoms in the general formula (1) is in the range of n to n × 12, and the total number of carbon atoms in the general formula (2) is (l + k) to (l + k) × 12. Within range.)

In the general formulas (1) and (2), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and a silicon atom-containing group having 1 to 3 silicon atoms. In view of ease of handling, ease of handling, and solubility in a hydrophobic organic solvent, a substituted or unsubstituted hydrocarbon group is preferred, and an unsubstituted hydrocarbon group is more preferred. In the general formulas (1) and (2), a plurality of R may be the same or different.
When R in the general formulas (1) and (2) is a substituted or unsubstituted hydrocarbon group, the range of the number of carbon atoms in R is 1 to 12, preferably 2 to 10, more Preferably it is 3-10, More preferably, it is 4-8.

  The total number of carbon atoms contained in the general formulas (1) and (2) is in the range of n to n × 12 in the general formula (1), preferably n × 2 to n × 10, more preferably n × 3 to n × 10, more preferably n × 4 to n × 8, and most preferably n × 4. In the general formula (2), it is within the range of (l + k) to (l + k) × 12, preferably (l + k) × 2 to (l + k) × 10, more preferably n (l + k) 3 to (l + k) × 10. More preferably, it is (l + k) × 4 to (l + k) × 8, and most preferably (l + k) × 4.

Specific examples of the hydrocarbon group as R in the general formulas (1) and (2) include linear saturated hydrocarbon groups (for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl). , N-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl), a straight chain unsaturated hydrocarbon group (eg, vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, Nonenyl, decenyl, undecenyl, dodecenyl, etc.), branched saturated hydrocarbon groups (eg, i-propyl, i-butyl, t-butyl, sec-butyl, i-pentyl, neopentyl, i-hexyl, i-heptyl, i -Octyl, t-octyl, i-nonyl, i-decyl, i-undecyl, i-dodecyl, etc.), a branched unsaturated hydrocarbon group (for example, 2-methyl) Propenyl, etc.), saturated cyclic hydrocarbon groups (eg, cyclopentyl, cyclohexyl, etc.), unsaturated cyclic hydrocarbon groups (eg, cyclohexenyl, cyclohexenylethyl, etc.), aromatic nucleus-containing hydrocarbon groups (eg, benzyl, phenethyl, Aralkyl groups such as 2-methylbenzyl, 3-methylbenzyl and 4-methylbenzyl, aromatic alkenyl groups such as PhCH═CH— group and CH ₂ ═CHC ₆ H ₄ — group, phenyl group, tolyl group or xylyl group Aryl group and the like.

Among these hydrocarbon groups, bulky (bulky) structure hydrocarbon groups of various non-linear structures are preferable from the viewpoint of ease of synthesis of polyhedral silsesquioxane, and examples thereof include branched saturated hydrocarbons. A branched structure hydrocarbon group such as a group, a branched unsaturated hydrocarbon group, a cyclic structure-containing saturated hydrocarbon group, a cyclic structure-containing unsaturated hydrocarbon group, and an aromatic ring-containing hydrocarbon group. Of these, saturated branched hydrocarbon groups such as branched saturated hydrocarbon groups and cyclic saturated hydrocarbon groups, and aromatic hydrocarbon groups are preferred, and branched saturated hydrocarbon groups are most preferred.
Preferred examples of the non-linear bulky (bulky) structure hydrocarbon group used in the present invention include various bulky hydrocarbon groups having 3 to 10 carbon atoms. Examples include i-propyl group, i-butyl group, i-octyl group, cyclopentyl group, cyclohexyl group, cyclohexenyl group, phenyl group and the like, and more preferred specific examples are i-butyl group, i-octyl. Group, cyclopentyl group, and cyclohexyl group, and the most preferred example is i-butyl group.

  Examples of the substituted hydrocarbon group in the present invention include an ether bond, a hydroxyl group, a thiol group, a thioether group, a carbonyl group, a carboxyl group, a thiol group, a thioether bond, and a hydrogen atom of the hydrocarbon group or a part of the main chain skeleton. Sulfone group, aldehyde group, epoxy group, amino group, substituted amino group, amide group (bond), imide group (bond), imino group, urea group (bond), urethane group (bond), isocyanate group, cyano group, etc. Examples thereof include those partially substituted with a substituent such as a polar group (polar bond), a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

When the general formulas (1) and (2) include the polar group (polar bonding group) -containing group, the total number of the polar group (polar bonding group) -containing groups is preferably within 3; Preferably it is within 2, more preferably 1.
As the silicon atom-containing group having 1 to 3 silicon atoms, which is adopted as R in the general formulas (1) and (2), those having a wide range of structures are adopted. For example, the general formula (11) or Examples include a group having the structure of the general formula (12).

N ′ in the general formula (11) is 1, 2 or 3. R ^a , R ^b and R ^c in the general formula (11) are a hydrogen atom, a chlorine atom, or a hydrocarbon group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 6 carbon atoms. The total number of carbon atoms in the general formula (11) is preferably 10 or less, more preferably 5 or less, and even more preferably 3. Examples of R ^a , R ^b and R ^c include aliphatic hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group and cyclohexyl group, unsaturated hydrocarbon bond-containing groups such as vinyl group and propenyl group, An aromatic hydrocarbon group such as a phenyl group, a benzyl group or a phenethyl group is exemplified, and a methyl group is particularly preferable. In general formula (11), two or more hydrogen atoms are not linked to the same silicon atom.
Specific examples of the silicon atom-containing group represented by the general formula (11) include a trimethylsiloxy group (Me ₃ SiO-), a dimethylsiloxy group (HMe ₂ SiO-), a dimethylphenylsiloxy group (Me ₂ PhSiO-), and phenethyl. Examples include dimethylsiloxy group, dimethyl-n-hexylsiloxy group, dimethylcyclohexylsiloxy group, vinyldimethylsiloxy group and the like.

In the general formula (12), n ″ is 0, 1 or 2. Ra is a divalent hydrocarbon group having 1 to 9 carbon atoms. Specific examples of the Ra group include —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ — and the like. R ^a , R ^b , R ^c , R ^d and R ^e are selected from the same groups as R ^a , R ^b and R ^{c in the} general formula (11). The total number of carbon atoms in the general formula (12) is preferably 12 or less, more preferably 8 or less, and even more preferably 5.
Of the polyhedral oligosilsesquioxane in the present invention, the cage silsesquioxane represented by the general formula (1) will be described in more detail.
(RSiO _3/2 ) _n (1)

Examples of the cage silsesquioxane represented by the general formula (1) include (RSiO _3/2 ) ₈ or a type represented by a chemical formula of the following general formula (13), (RSiO _3/2 ) ₁₀ , Examples thereof include a type represented by the chemical formula of the following general formula (14), (RSiO _3/2 ) ₁₂ or a type represented by the following general formula (15).
The value of n in the caged silsesquioxane represented by the general formula (1) (RSiO _3/2 ) _n of the present invention is an integer of 6 to 14, preferably 6, 8, 10, 12. Yes, more preferably 8, 10, even more preferably 8.

Next, the cage-shaped silsesquioxane partial cleavage structure represented by the general formula (2) used in the present invention will be described in more detail.
(RSiO _3/2 ) _l (RXaSiO) _k (2)
In the general formula (2), Xa is a group selected from OH and the group defined by R, and a plurality of Xa may be the same or different. (RXaSiO) A plurality of Xa's in _k may be linked to each other to contain a silicon atom, or may form a linked structure. l is an integer of 2 to 10, preferably an integer of 4 to 8, and more preferably 4. k is an integer of 2 to 4, preferably 3.

Of the partially cleaved silsesquioxane structure represented by the general formula (2) used in the present invention, a silanol compound represented by the general formula (3) is preferable.
(R ¹ SiO _3/2 ) _l (R ¹ (OH) SiO) _k (3)
In the general formula (3), R ¹ is selected from a hydrogen atom, a substituted group having 1 to 12 carbon atoms, and an unsubstituted hydrocarbon group, and a plurality of R ¹ may be the same or different.
The substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms in R ¹ of the general formula (3) is a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms in R of the general formula (2). The same and preferred types are also the same. l is an integer from 2 to 10, and k is an integer from 2 to 4. The total number of carbon atoms in general formula (3) and its preferred range are the same as in general formula (2).

Examples of the silanol compound represented by the general formula (3) include a type represented by the general formula (4) or the general formula (5), or a type represented by the general formula (16) or the general formula (17). Etc.
(R ¹ SiO _3/2 ) ₄ (R ¹ (OH) SiO) ₃ (4)
(R ¹ SiO _3/2 ) ₆ (R ¹ (OH) SiO) ₃ (16)

In the general formula (5) and the general formula (17), the R ¹ group and the OH group bonded to the same silicon atom may be exchanged with each other. Among the silanol compounds represented by the general formula (3), a trisilanol compound represented by the general formula (4) or (5) is particularly preferable. Formula (4), (5), (16) and (17) ^{R 1} in is the same as ^{R 1} in the general formula (3), the preferred range and type is also the same.

a-2) Alkali Metal Compound The alkali metal compound in the present invention is a general term for compounds having an alkali metal atom. The alkali metal atom is a metal atom selected from lithium, sodium, potassium, rubidium and cesium, and among them, lithium, sodium and potassium are preferable, and lithium is more preferable.
Examples of alkali metal compounds used in the present invention include alkali metal salts (organic acid salts and inorganic acid salts), basic alkali metal compounds (alkali metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates). , Alkali metal alkoxides, etc.), preferably alkali metal salts, more preferably alkali metal acetates, phosphates, hydrochlorides, sulfates and nitrates, and more preferably acetates and Phosphate.
In the polyhedral oligosilsesquioxane, one kind of alkali metal compound may be contained, or a plurality of compounds may be contained.

  Examples of the organic acid salt forming the alkali metal salt used in the present invention include a wide variety of organic acid salts such as organic carboxylate, organic sulfonate, and organic phosphonate. Examples of organic carboxylates include saturated carboxylates such as formate, acetate and propionate, unsaturated carboxylates such as crotonic acid and acrylate, and aromatic carboxylates such as benzoate And halogen atom-containing carboxylates such as oxalate, trichloroacetate and trifluoroacetate. The number of carbon atoms in these organic acid salts is preferably 10 or less, more preferably 6 or less, still more preferably 3 or less, and most preferably 2.

A wide variety of inorganic acid salts can be used as the inorganic acid salt forming the alkali metal salt used in the present invention. Examples of inorganic acid salts include carbonates, hydrogen carbonates, sulfates, Hydrogen sulfate, sulfite, thiosulfate, phosphate, phosphite, hypophosphite, nitrate, borate, cyanate, thiocyanate, silicate, iodate, hydrohalide (For example, hydrofluoric acid salt, hydrochloride, hydrobromide, hydroiodide) and the like.
The alkali metal compound in the present invention is a basic alkali metal compound used for the synthesis of polyhedral oligosilsesquioxane, a compound obtained by modification during or after the synthesis reaction, or an acid in the synthesis process of polyhedral oligosilsesquioxane. It may be modified to an alkali metal salt by treatment.

a-3) Hydrophobic Organic Solvent The hydrophobic organic solvent used for the purification of the present invention has a water solubility at 20 ° C. of 1.0% by weight or less, preferably 0.5% by weight or less, more preferably 0.8%. An organic solvent of 3% by weight or less, most preferably 0.1% by weight or less is used. An organic solvent having a low water solubility in a hydrophobic organic solvent is preferable because a purification operation for removing the alkali metal compound is facilitated.
As the hydrophobic organic solvent used in the present invention, polyhedral oligosilsesquioxane for purification purposes is 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, most preferably at 20 ° C. An organic solvent that dissolves 20% by weight or more is used.

  Specific examples of the hydrophobic organic solvent used in the present invention include hexane, 2-methylpentane, 2,2-dimethylbutane, heptane, n-octane, isooctane, nonane, 2,2,5-tritylhexane, decane. Aliphatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, biphenyl, styrene, etc., methyl chloride, chloroform, carbon tetrachloride, ethyl chloride, 1,1-dichloroethane, 1 , 2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, 1,1- Halogenated hydrocarbon solvents such as dichloroethylene, allyl chloride and chlorobenzene, dibutyl ether Le, hydrophobic ether solvents such as dihexyl ether.

Among these various hydrophobic organic solvents, aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents are more preferable in terms of operability and purification effects. These hydrophobic organic solvents may be a mixture of two or more types of solvents.
Below, the refinement | purification process of the polyhedral silsesquioxane of this invention is demonstrated.
The main embodiments relating to the purification process of the present invention are:
“(1) A composition containing at least a polyhedral oligosilsesquioxane and an alkali metal compound is brought into contact with a hydrophobic organic solvent having a water solubility at 20 ° C. of 1.0% by weight or less to form a hydrophobic organic A step of dissolving polyhedral oligosilsesquioxane in a solvent and obtaining an organic phase containing a fine particle dispersion; and (2) an organic phase containing the polyhedral oligosilsesquioxane obtained in the previous step and the fine particle dispersion. Separating the fine particle dispersion from the polyhedral silsesquioxane, ”
“A method for purifying a polyhedral oligosilsesquioxane, wherein the step (2) of separating the fine particle dispersion is a filtration step”,
And “a method for purifying a polyhedral oligosilsesquioxane represented by the general formula (1) or (2) containing an alkali metal compound, wherein (1 ′) at least a polyhedral oligosilsesquioxane and an alkali metal compound Contacting the composition containing both with a hydrophobic organic solvent having a water solubility at 20 ° C. of 1.0% by weight or less to dissolve the polyhedral oligosilsesquioxane in the hydrophobic organic solvent; ') A process for purifying the polyhedral oligosilsesquioxane, characterized by comprising a step of filtering the organic phase obtained in the previous step ",
It is.

The steps (1), (1 ′), (2) and (2 ′) of the purification method will be described below.
b-1) Steps for purification of polyhedral silsesquioxane (1) and (1 ′)
The “composition containing both at least the polyhedral oligosilsesquioxane and the alkali metal compound” used in the steps (1) and (1 ′) of the present invention includes the polyhedral oligosilsesquioxane and the alkali metal compound. Other than that, various compounds, substances, solvents and the like may be included.
For example, the composition may contain various organic compounds other than alkali metal compounds, inorganic compounds, organic / inorganic composite compounds and salts, and polyhedral oligosyl such as silsesquioxane polymers and silicon atom-containing oligomers. A silicon compound other than sesquioxane may be contained, various polymers and oligomers not containing a silicon atom may be contained, and further, water and other solvents may be contained. Therefore, the “composition containing both at least the polyhedral oligosilsesquioxane and the alkali metal compound” used in the steps (1) and (1 ′) of the present invention is solid, liquid, dispersed liquid But you can.

  One of preferred forms of the “composition containing both at least a polyhedral oligosilsesquioxane and an alkali metal compound” used in the steps (1) and (1 ′) of the present invention is a polyhedral oligosilsesquioxane. Is a composition having a content of 80% by weight or more. In this case, the content of the polyhedral oligosilsesquioxane in the composition used in the steps (1) and (1 ′) is preferably 80% by weight or more from the viewpoint of the operability and efficiency of the step. More preferably, it is 90 weight% or more, More preferably, it is 95 weight% or more, Most preferably, it is 99 weight% or more. If the content of the polyhedral oligosilsesquioxane is too low, the operation efficiency decreases.

Another preferred embodiment of the steps (1) and (1 ′) of the present invention is “an aqueous solution in which steps (1) and (1 ′) contain at least both a polyhedral oligosilsesquioxane and an alkali metal compound. The dispersion composition is contacted with a hydrophobic organic solvent to extract polyhedral oligosilsesquioxane in the hydrophobic organic solvent and then phase-separated to dissolve the polyhedral oligosilsesquioxane in the hydrophobic organic solvent. A method for purifying a polyhedral oligosilsesquioxane, which is a step of obtaining an organic phase containing a fine particle dispersion.
The aqueous dispersion composition is a composition in which a polyhedral oligosilsesquioxane is dispersed and an alkali metal compound is dissolved and / or dispersed in an aqueous medium or a mixed medium containing at least water. As a specific example of the aqueous dispersion composition, “polyhedral oligosilsesquioxane was dispersed in a water-containing medium and an alkali metal compound was dissolved or suspended in a process for producing polyhedral oligosilsesquioxane”. Composition ", but is not limited thereto.

Polyhedral oligosilsesquioxane is extracted into the hydrophobic organic solvent by bringing the aqueous dispersion composition into contact with the hydrophobic organic solvent. After this operation, the aqueous phase and the hydrophobic organic solvent phase are phase-separated to separate the hydrophobic organic solvent phase, and the polyhedral oligosilsesquioxane is dissolved in the hydrophobic organic solvent, and a minute amount of the fine particle dispersion is formed. A contained organic phase is obtained.
The water content in the aqueous dispersion composition should be sufficient to form a two-phase system of an aqueous phase and an organic phase when the aqueous dispersion composition is contacted with a hydrophobic organic solvent. That's fine. However, in order to obtain practical operability, the lower limit of the water content in the aqueous dispersion composition is preferably 1% by weight, more preferably 10% by weight, still more preferably 20% by weight, most preferably. Is 30% by weight. On the other hand, the upper limit of the water content is preferably 99% by weight, more preferably 95% by weight, still more preferably 90% by weight, and most preferably 85% by weight. When the water content is too small, it becomes difficult to form a two-phase system of an organic phase and an aqueous phase, and when the water content is too large, the production efficiency of polyhedral silsesquioxane is deteriorated. Even when the water content is low and it becomes difficult to form a two-phase system of an organic phase and an aqueous phase, the insoluble component including the homogeneous solution in which the polyhedral oligosilsesquioxane is dissolved and the fine particle dispersion are separated. Thus, the purification method of the present invention can be performed.

b-2) Steps for purifying polyhedral silsesquioxanes (2) and (2 ′)
As a method for separating the fine particle dispersion and the polyhedral oligosilsesquioxane in the purification step (2) of the present invention, various separation methods can be employed. Specific examples of the separation method include a filtration method, a centrifugal separation method, an adsorption method (for example, treatment with an adsorbent for polar substances), a column separation method, and the like, but are not limited thereto, You may combine methods. Among these separation methods, a filtration treatment method is preferred from the viewpoint of simplicity of operation and separation efficiency.
As the filtration treatment method used in the purification steps (2) and (2 ′) of the present invention, filtration with a filter is more preferable. You may implement combining a filtration processing method and other processing methods like the combination of the filtration method and an adsorption method.

Various materials such as natural polymers, synthetic polymers, ceramics, and metals can be used as filter materials for filtration, and the forms thereof are various porous membrane structures (flat membranes, pleats). Membranes, hollow fiber membranes, etc.), various porous structures such as sintered body structures, cloth-like or non-woven fibrous structures, or particulate matter-filled structures. Furthermore, filtration by a filter using a filter aid may be used.
The average pore diameter of the porous filter is preferably 0.005 μm or more and 100 μm or less, but from the viewpoint of simplicity of operation, it is preferably 0.01 μm or more and 10.0 μm or less, more preferably 0.01 μm or more and 5.0 μm or less Preferably it is 0.01 micrometer or more and 3.0 micrometers or less.
As the shape of the filter, a membrane filter is preferable in terms of operational convenience. The form of the membrane filter can take various forms such as a flat membrane, a pleated membrane, and a hollow fiber membrane. Among these membrane filters, the membrane filter is more preferable in terms of operability and purification efficiency.

As a constituent material of the hydrophobic membrane filter, the contact angle with water at 25 ° C. to 35 ° C. is preferably 40 degrees or more, more preferably 60 degrees or more, further preferably 70 degrees, and most preferably 85 degrees or more. Materials are used.
Specific examples of the hydrophobic membrane filter include membrane filters made of polypropylene (PP), polyethylene (PE), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polysulfone, or the like. Among them, a hydrophobic membrane filter made of PTFE is particularly preferably used from the viewpoint of the wide range of usable solvents and the purification efficiency.

These hydrophobic membrane filters are used in various forms, and examples thereof include various forms such as a flat membrane, a pleated membrane, and a hollow fiber membrane.
The average pore size of the hydrophobic membrane filter used in the method of the present invention is preferably 0.005 μm to 100 μm, more preferably 0.01 μm to 10.0 μm, and still more preferably 0.01 μm to 5.0 μm. Hereinafter, it is most preferably 0.01 μm or more and 3.0 μm or less.
In the present invention, the removal of the alkali metal compound from the polyhedral oligosilsesquioxane can be easily confirmed by using, for example, ion chromatography with an anion or cation, ICP (dielectric coupling plasma emission analysis), IR or the like. However, ICP is preferable because of its good measurement limitability.

When the solvent is removed by various methods from the solution containing the polyhedral oligosilsesquioxane obtained in the step (2) or (2 ′), polyhedral silsesquioxane is obtained, which is a preferred embodiment of the present invention. One is that a polyhedral oligosilsesquioxane is further added to the solution containing the polyhedral oligosilsesquioxane obtained in step (2) or (2 ′) by adding a poor solvent of the polyhedral oligosilsesquioxane. A purification method of polyhedral oligosilsesquioxane, which is characterized by adding a step of precipitating oxane ”.
An application example of this method will be described below. For example, in a method for producing a polyhedral oligosilsesquioxane using a basic alkali metal compound, an oligomeric silsesquioxane compound may be produced in addition to the target polyhedral oligosilsesquioxane. Even in such a case, when the poor solvent addition treatment is performed, only the polyhedral oligosilsesquioxane is selectively precipitated, and the oligomeric silsesquioxane compound remains in the solution. Oligosilsesquioxane and oligomeric silsesquioxane compounds can be separated.

The oligomeric silsesquioxane compound thus separated can be used again as a silicon compound raw material used for the reaction with the basic alkali metal compound.
The poor solvent used in this operation may be a solvent that is miscible with the hydrophobic organic solvent used in the above step and has a low solubility of the polyhedral oligosilsesquioxane. Specifically, as the poor solvent, those having a polyhedral oligosilsesquioxane solubility at 20 ° C. of preferably less than 10% by weight, more preferably less than 5% by weight, and even more preferably less than 1% by weight are used. The
Specific examples of the poor solvent include nitrile solvents such as acetonitrile and propionitrile, but are not limited thereto.

Below, the manufacturing method of the high purity polyhedral oligosilsesquioxane which combined the purification method of said polyhedral oligosilsesquioxane and the manufacturing method of polyhedral oligosilsesquioxane is demonstrated.
One of the preferred embodiments of the present invention is a reaction of a basic alkali metal compound with at least one silicon compound selected from “A) a compound represented by the general formula (6) and a condensate thereof as a raw material. A process for producing a polyhedral oligosilsesquioxane represented by the following general formula (1), and B) represented by the general formula (1) according to any one of claims 1 to 4 and 7 to 14. And a method for producing a high-purity polyhedral oligosilsesquioxane, which is combined with a purification step of polyhedral oligosilsesquioxane.

RSiXb ₃ (6)
(RSiO _3/2 ) _n (1)
Another preferred embodiment of the present invention is a reaction with a basic alkali metal compound using, as a raw material, at least one silicon compound selected from “A ′) a compound represented by general formula (6) and a condensate thereof” A process for producing a polyhedral oligosilsesquioxane represented by the following general formula (2) (wherein at least one Xa in the following general formula (2) is an OH group) In the case of producing a polyhedral oligosilsesquioxane represented by the following general formula (2) by further applying an acid treatment operation to the reaction, and B ′) any one of claims 1 to 14 A method for producing a high-purity polyhedral oligosilsesquioxane, which is combined with a purification step of a polyhedral oligosilsesquioxane represented by the general formula (2) according to claim 1 It is.

RSiXb ₃ (6)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
In the above two production methods, the polyhedral oligosilsesquioxane represented by the general formulas (1) and (2) is the polyhedral oligosil represented by the general formulas (1) and (2) in the purification method. Same as sesquioxane.
In general formula (6), R has the same definition as in general formulas (1) and (2). Xb is preferably a group selected from an OH group, a halogen atom, and an —OQ group (Q is a hydrocarbon group having 1 to 10 carbon atoms), and more preferably an OH group, a chlorine atom, and a carbon atom number of 1 ˜4 alkoxy groups, most preferably an alkoxy group having 1 to 2 carbon atoms. The plurality of Xb may be the same or different.

Examples of the compound represented by the general formula (6) include trihalosilane represented by RSiCl ₃ and RSiBr ₃ , trialkoxysilane represented by RSi (OMe) ₃ and RSi (OEt) ₃ , and the like.
In the steps A) and A ′), at least one kind of silicon compound selected from the compound represented by the general formula (6) and the condensate thereof is used as a raw material, but represented by the general formula (6). When the compound is used, it is more preferable because the raw material is easily obtained and the yield is often good.
The condensate of the compound represented by the general formula (6) may be any compound obtained by condensing a plurality of compounds represented by the general formula (6) via Si—O—Si bonds. This Si—O—Si bond is formed from the compound represented by the general formula (6) by a reaction such as a hydrolysis reaction, a dehydration reaction, a dealcoholization reaction, or a dehydrochlorination reaction.

Examples of the condensate of the compound represented by the general formula (6) include an amorphous polysilsesquioxane, a ladder-like polysilsesquioxane, a cage-like silsesquioxane or a partial cleavage structure thereof, a general formula Examples include various condensates linked by Si—O—Si bonds, such as silsesquioxane oligomers, which are formed by connecting the compound represented by (6) from several molecules to several tens of thousands of molecules. However, among the compounds represented by the general formula (6) and the condensates thereof, the compounds represented by the general formula (6) are more preferable because they generally have good operability and yield.
A preferred embodiment of a method for producing a high-purity polyhedral oligosilsesquioxane is “a compound represented by the general formula (6) is a compound represented by the following general formula (7), and is generally produced and purified. “The production method wherein the polyhedral oligosilsesquioxane of the formula (2) is a compound represented by the following general formula (8)”.

R ² SiXc ₃ (7)
(R ² SiO _3/2 ) _l (R ² (OH) SiO) _k (8)
R ² in the general formulas (7) and (8) is a hydrocarbon group having 2 to 10 carbon atoms, and the hydrocarbon group has 2 to 2 carbon atoms as R in the general formulas (1) and (2). 10 hydrocarbon groups are the same, and the preferred types are also the same. The total number of carbon atoms in the general formula (8) is preferably (l + k) × 2 to (l + k) × 10, more preferably (l + k) 3 to (l + k) × 10, and further preferably (l + k) × 4 to (L + k) × 8, most preferably (l + k) × 4.

_Xc in General formula (7) is a C1-C4 alkoxyl group or a chlorine atom, and _Xc may be comprised from the some group chosen from these groups. Specific examples of the alkoxyl group having 1 to 4 carbon atoms include MeO- group, EtO- group, nPrO- group, iPrO- group, nBuO- group, iBuO- group, sBuO- group, and tBuO- group. Among these, MeO-group and EtO-group are particularly preferable in view of availability and operability. l is an integer from 2 to 10, and k is an integer from 2 to 4.
A more preferred embodiment of the method for producing a high-purity polyhedral oligosilsesquioxane is “a structure in which the compound represented by the general formula (8) in the above production method is represented by the general formula (9) or (10)”. A method for producing a high-purity polyhedral oligosilsesquioxane, which is characterized in that
(R ³ SiO _3/2 ) ₄ (R ³ (OH) SiO) ₃ (9)

The structure of R ^{3 in} the general formulas (9) and (10) and the preferred type thereof are the same as those of R ² in the general formula (8), but more preferably an isobutyl group. In the general formula (10), the R ³ group and the OH group bonded to the same silicon atom may be exchanged for each other.
Hereinafter, steps A) and A ′) in the method for producing the high-purity polyhedral oligosilsesquioxane will be described in more detail.
As the solvent used in the reaction of the above steps A) and A ′), a wide variety of solvents that dissolve the compound represented by the general formula (6) or its condensate are preferably used. Specific examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone and MIBK, various polar solvents such as ether solvents, and nonpolar solvents such as aromatic hydrocarbons such as toluene and xylene. Of these, ketone solvents such as acetone, methyl ethyl ketone, MIBK and the like are preferable, but are not limited to these solvents. The step 1) can also be carried out in a bulk reaction without a reaction solvent.

The basic alkali metal compound used for the reaction in the above steps A) and A ′) exhibits basicity, and is generally obtained by condensation reaction or rearrangement reaction of the compound represented by the general formula (6) and its condensate. What is necessary is just to be able to form the polyhedral oligosilsesquioxane represented by the formula (1) or (2). Specific examples thereof include alkali metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates, alkali metal alkoxides and the like, and alkali metal hydroxides are particularly preferable from the viewpoint of operability and reactivity.
Examples of the alkali metal atom include lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium and potassium, and more preferably lithium. In particular, when producing a polyhedral oligosilsesquioxane represented by the general formula (8), (9) or (10), lithium hydroxide is preferable.

The reaction in the above steps A) and A ′) can be carried out at a wide range of temperatures depending on the reaction rate of the combination of the basic alkali metal compound and the silicon compound raw material, but preferably from 30 ° C. to 300 ° C. Preferably it is in the range of 50 ° C to 250 ° C, more preferably 70 ° C to 200 ° C, most preferably 80 ° C to 180 ° C. If the reaction temperature is too low, a practical reaction rate cannot be obtained, and if the reaction temperature is too high, side reactions become prominent. Therefore, the reaction temperature is appropriately selected according to the reaction system.
The reaction in the above steps A) and A ′) may be performed under reduced pressure, normal pressure, or under pressure using a pressure vessel or the like. When the reaction temperature is set higher than the boiling point of the reaction mixture consisting of the reaction raw material, reaction solvent, water added to the reaction system, etc., the reaction is carried out under pressurized conditions.

In the pressure reaction, the upper limit of the internal pressure is preferably 5 MPa, more preferably 2 MPa, more preferably 0.5 MPa, most preferably 0, considering the pressure resistance performance, operability and reaction results of the reaction vessel. .2 MPa. In general, it is preferable to carry out the reaction under high temperature and pressure conditions within the above pressure range, since both a high reaction rate and a high selectivity can be achieved. Although there is no lower limit of the pressure of the pressure reaction, the gauge pressure is preferably 0.01 MPa, more preferably 0.05 MPa, in order to realize a substantially high temperature / pressure reaction effect.
In the above step A ′), when a silanol group-containing compound is produced, an acid treatment operation is required after the reaction between the silicon compound raw material and the basic alkali metal compound. For example, when the silanol compound represented by the general formula (8) is produced by utilizing the reaction between the compound represented by the general formula (7) and the basic alkali metal compound, the general formula (7) An acid treatment operation is added after the reaction between the compound represented and the basic alkali metal compound.

By this acid treatment operation, the silanol alkoxide structure (Si-O-alkali metal) formed by the reaction before the treatment is converted to the silanol structure (Si-OH), and the silanol compound represented by the general formula (8) Is formed. At the same time, the basic alkali metal compound remaining in the reaction system is converted into an alkali metal salt.
In the steps A) and A ′), when a polyhedral oligosilsesquioxane containing no silanol group is produced, an acid treatment operation is not always necessary, but in order to facilitate the subsequent product isolation operation, etc. An acid treatment operation may be performed for the purpose.
A wide range of organic and inorganic acids can be used as the acid used in the acid treatment operation in step A ′). Examples thereof include organic acids such as formic acid, acetic acid, propionic acid and benzoic acid, and inorganic acids such as hydrochloric acid, phosphoric acid, carbonic acid, nitric acid and sulfuric acid, preferably acetic acid, hydrochloric acid, nitric acid, phosphoric acid and sulfuric acid. More preferred are acetic acid and phosphoric acid. If the acid strength is too strong, the yield of the desired polyhedral silsesquioxane decreases, and if the acid strength is too weak, a substantial acid treatment effect cannot be obtained. An acid strength acid is selected. Accordingly, the pKa at 25 ° C. in the aqueous solution (logarithm of the reciprocal of the acid dissociation constant) is preferably an acid in the range of −2.0 to +5.5, more preferably +1.5 to +5.0. Is done.

As a preferable mode for carrying out the above-described step A ′) of the present invention, “step A ′) includes a silicon compound and an alkali metal hydroxide as A′-1) raw materials in the presence of water at 30 to 300 ° C. And a method for producing a high-purity polyhedral oligosilsesquioxane characterized by comprising a step of reacting in a range and a step of treating the reaction mixture produced in the preceding step with an acid with an acid ”.
The reaction temperature in step A′-1) is preferably in the range of 30 to 300 ° C., more preferably in the range of 70 to 200 ° C., and most preferably in the range of 80 to 180 ° C. As the alkali metal hydroxide used in step A′-1), all alkali metal hydroxides can be used, but lithium hydroxide, sodium hydroxide and potassium hydroxide are preferable, and water is more preferable. Lithium oxide.

As the acid used in Step A′-2), the same acid as that used in Step A ′) can be used, but preferably pKa (acid dissociation constant) at 25 ° C. in an aqueous solution. An acid having a logarithm of the reciprocal number in the range of -2.0 to +5.5 is used, more preferably an acid in the range of +1.5 to +5.0 is used, and more preferably acetic acid is used.
As described above, the polyhedral oligosilsesquioxane having an extremely low alkali metal compound content can be efficiently produced by the method of the present invention. The method of the present invention is suitable for the production of a high-purity polyhedral oligosilsesquioxane, particularly a trisilanol group-containing cage-like siloxane compound contained in the general formula (2).

By the method of the present invention, high-purity polyhedral oligosilsesquioxane having an alkali metal atom content of 50 ppm or less, 10 ppm or less, 5 ppm or less, 1 ppm or less, 0.5 ppm or less, or 0.3 ppm or less can be easily obtained.
High purity polyhedral oligosilsesquioxane and trisilanol group-containing cage-like siloxane compounds are useful as modifiers for functional resins such as polymers for electronic materials. In addition, it can be converted into various derivatives and used as a raw material for electronic materials having excellent heat resistance and electrical characteristics.
In general, in the field of electronic materials, alkali metal ion impurities in a material may cause a serious problem in the apparatus. Therefore, it is necessary to extremely reduce the content of alkali metal ions or alkali metal compounds in the material. However, the present inventors have studied a method for producing polyhedral oligosilsesquioxane or trisilanol group-containing cage-type siloxane having a low content of alkali metal ions or alkali metal compounds that meet such requirements. It was difficult to produce a high purity product by the production method.

However, the method of the present invention has enabled the first efficient production method of high purity polyhedral oligosilsesquioxane or trisilanol group-containing cage-type siloxane having a low alkali metal compound content.
Thus, the method of the present invention provides a method for efficiently producing high-purity polyhedral oligosilsesquioxane or trisilanol group-containing cage-type siloxane useful as various resin modifiers and raw materials for electronic materials. It is extremely important industrially.

Hereinafter, embodiments of the present invention will be described in detail with reference to Examples and Comparative Examples. Materials, reagents, devices, substance amounts, ratios, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following examples.
For identification of polyhedral oligosilsesquioxane, ¹ HNMR (manufactured by JEOL, GSX400 type, CDCl ₃ as a solvent), ²⁹ SiNMR (manufactured by JEOL, GSX400 type, CDCl ₃ containing 1% TMS as a solvent) APCI-MS (manufactured by Thermo Electron, LCQ), ESI-MS (manufactured by Thermo Electron, LCQ), MALDITF-MS (manufactured by Shimadzu Corporation), and GC (manufactured by Shimadzu Corporation, GC2010) were used.

For identification of impurities, IR, GC, GPC, etc. were used, but for cation, cation chromatography (Yokogawa Analytical Systems, IC7000) and / or ICP-MS (Thermo elemental) Manufactured; Quartet ICP-MS, X-series, X7).
Anions were quantified using anion chromatography (Yokogawa Analytical Systems, IC7000).
The silicon compound used was a product of GELEST (USA). In addition, the products of Wako Pure Chemical Industries, Ltd. were used for the bases, acids, organic solvents, etc. shown in the following examples.

[Example 1]
<Synthesis and Purification of (iBuSiO _1.5 ) ₄ (iBu (OH) SiO _1.0 ) ₃ >
6.36 g (152 mmol) of lithium hydroxide monohydrate was placed in a pressure resistant reaction vessel having an internal volume of 500 ml, and 4.64 ml (258 mmol) of pure water and 66 ml (908 mmol) of acetone were sequentially added and stirred. To this, 55.98 g (314 mmol) of isobutyltrimethoxysilane was injected, and the reaction vessel was closed.
While stirring the reaction solution, the temperature of the oil bath was raised to 100 ° C., and the reaction was continued for 3 hours. After completion of the reaction, the reaction vessel was allowed to cool and the reaction solution was transferred to a 1000 ml eggplant flask. While stirring the reaction solution, 300 ml of a 1N aqueous acetic acid solution was added to obtain a slurry liquid in which fine particle substances were dispersed.

To this slurry solution, 300 ml of toluene was added and stirred, and then allowed to stand to separate into two phases. Next, the toluene phase obtained by phase separation was filtered through a PTFE membrane filter (manufactured by ADVANTEC) having a pore size of 0.10 μm. The filtrate was concentrated with an evaporator. When solid matter began to precipitate, the concentration was stopped, and 300 ml of acetonitrile was added to precipitate the solid matter. The solid matter was separated by filtration and dried at 80 ° C. under a vacuum pressure of 75 cmHg for 2 hours to obtain 30.2 g of a white powder.
^{According to 29} SiNMR spectrum analysis, the white powdery substance was found to be a polyhedral oligosilsesquioxy having a trisilanol structure represented by (iBuSiO _1.5 ) ₄ (iBu (OH) SiO _1.0 ) ₃ or general formula (18). It was confirmed to be sun (partially cleaved structure of a cage silsesquioxane having a trisilanol structure).

（式中、同一のケイ素原子に結合しているi-Bu基とOH基はそれぞれお互いの位置を交換したものでもよい。）

(In the formula, the i-Bu group and the OH group bonded to the same silicon atom may be exchanged with each other.)

A yield of 30.2 g corresponds to a yield of 85% as a trisilanol compound. The purity determined from the ²⁹ Si NMR spectrum of the trisilanol compound was 99%. The acetate ion content in the trisilanol compound was 10 ppm or less (below the detection limit) according to anion chromatography, and the lithium atom content was 0.13 ppm according to ICP-MS analysis.
From the above results, by the method of the present invention, a highly pure polyhedral oligosilsesquioxane (partially cleaved structure of a cage silsesquioxane having a trisilanol structure) with a low content of alkali metal compound is efficiently produced. You can see that you can get it.
²⁹ Si NMR spectrum data {δ (ppm); −68.6 (3), −67.3 (1), −58.9 (3)}

[Comparative Example 1]
The same operation as in Example 1 was performed, except that the filtration step using a toluene phase PTFE membrane filter was omitted. As a result, the yield of the obtained trisilanol compound was 86%, and the purity determined from ²⁹ SiNMR spectrum was 98%.
In addition, the lithium atom content in the trisilanol compound was 550 ppm according to ICP-MS analysis. From this result, the effect of the PTFE membrane filter treatment step exemplified in Example 1 is clear.

[Comparative Example 2]
6.36 g (152 mmol) of lithium hydroxide monohydrate was placed in a pressure resistant reaction vessel having an internal volume of 500 ml, and 4.64 ml (258 mmol) of pure water and 66 ml (908 mmol) of acetone were sequentially added and stirred. To this, 55.98 g (314 mmol) of isobutyltrimethoxysilane was injected, and the reaction vessel was closed. The temperature of the oil bath was raised to 100 ° C. while stirring, and the reaction was further continued for 3 hours.
After completion of the reaction, the reaction vessel was allowed to cool and the reaction solution was transferred to a 1000 ml eggplant flask. Thereafter, the following operation was performed according to the method described in Patent Document 1 (WO01 / 010871 pamphlet) except that 1N acetic acid aqueous solution was used as the acidic aqueous solution for quenching instead of 1N hydrochloric acid aqueous solution. It was.

That is, when the reaction solution was stirred and neutralized by adding 300 ml of a 1N aqueous acetic acid solution, a slurry liquid in which fine particle substances were dispersed was obtained. The particulate matter was filtered while washing with 300 ml of acetonitrile, and the obtained solid was further dried at constant temperature to obtain a white powder. As a result, the yield of the obtained trisilanol compound was 90%, and the purity determined from ²⁹ SiNMR spectrum was 97%.
The lithium atom content in the trisilanol compound obtained by this method was 1900 ppm according to ICP-MS analysis.

[Example 2]
300 g of toluene was added to 30 g of a crude trisilanol compound containing 1900 ppm of lithium atoms obtained in the same manner as in Comparative Example 2, and the mixture was sufficiently stirred, and then filtered through a PTFE membrane filter (ADVANTEC) having a pore size of 0.10 μm. . The filtrate was concentrated with an evaporator. When solid matter began to precipitate, the concentration was stopped, and 300 ml of acetonitrile was added to precipitate the solid matter.
The solid was separated by filtration and dried at 80 ° C. under a vacuum pressure of 75 cmHg for 2 hours to obtain 27.3 g of white powder (91% recovery). According to ICP-MS analysis, the lithium atom content in the trisilanol compound was 0.20 ppm.

[Example 3]
The same operation as in Comparative Example 2 was performed to obtain a crude trisilanol compound, but this time a 1N hydrochloric acid solution was used as the acidic solution for quenching. The obtained crude trisilanol was a crude trisilanol compound containing 1800 ppm of lithium atoms. When this crude trisilanol was purified by the same operation as in Example 2, trisilanol was obtained with a recovery rate of 95%. According to ICP-MS analysis, the lithium atom content in the trisilanol compound was 0.27 ppm.

[Example 4]
The same operation as in Comparative Example 2 was performed to obtain a crude trisilanol compound, but this time, a 1N phosphoric acid solution was used as an acidic solution for quenching. The resulting crude trisilanol was a crude trisilanol compound containing 3800 ppm lithium atoms. When this crude trisilanol was purified by the same operation as in Example 2, trisilanol was obtained with a recovery rate of 90%. The lithium atom content in the trisilanol compound was 0.15 ppm according to ICP-MS analysis.

[Comparative Example 3]
After adding 300 ml of diethyl ether to 30 g of a crude trisilanol compound containing 1900 ppm of lithium atoms obtained by the same operation as in Comparative Example 2, the mixture was sufficiently stirred, and then a hydrophilized PTFE membrane filter having a pore size of 5 μm (manufactured by Millipore). Filtration gave a clear filtrate.
The filtrate was concentrated with an evaporator. When solid matter began to precipitate, the concentration was stopped, and 300 ml of acetonitrile was added to precipitate the solid matter. The solid was separated by filtration and dried at 80 ° C. under a vacuum pressure of 75 cmHg for 2 hours to obtain 21.9 g of white powder (recovery rate 73%). The lithium atom content in the trisilanol compound was 257 ppm according to ICP-MS analysis.

[Example 5]
To a eggplant flask having a volume of 300 ml, 1.00 g (23.8 mmol) of lithium hydroxide monohydrate was added, and 20 ml of pure water, 88 ml of acetone, and 12 ml of methanol were added in that order and stirred. When 9.33 g (52.3 mmol) of isobutyltrimethoxysilane was added dropwise and refluxed at 72 ° C. for 3 hours, crystals were precipitated.
20 ml of 2.5N acetic acid aqueous solution was added and stirred for 2 hours. The dispersion containing crystals was dissolved in 50 ml of toluene solution, stirred, and allowed to stand to separate into two phases. The toluene phase obtained by phase separation was filtered through a PTFE membrane filter (manufactured by ADVANTEC) having a pore size of 0.10 μm to obtain a clear filtrate. The filtrate was concentrated with an evaporator. When solid matter began to precipitate, concentration was stopped, and 50 ml of acetonitrile was added to precipitate solid matter. The solid was separated by filtration and dried at 80 ° C. under a vacuum pressure of 75 cmHg for 2 hours to obtain 3.10 g of a white powder.
This white powdery substance was confirmed to be polyhedral oligosilsesquioxane represented by (iBuSiO _1.5 ) ₈ by ²⁹ Si NMR spectrum analysis. From ICP-MS, the Li ion in the polyhedral oligosilsesquioxane was 0.20 ppm.

[Example 6]
The same operation as in Example 1 was performed except that acetone was not used as a reaction solvent, to obtain 29.1 g of a white powder.
^The purity determined from the ²⁹ Si NMR spectrum of the trisilanol compound by ²⁹ Si NMR spectrum analysis was 97%. The acetate ion content in the trisilanol compound was 10 ppm or less (below the detection limit) according to anion chromatography, and the lithium atom content was 0.14 ppm according to ICP-MS analysis.

[Example 7]
A silicon compound mainly composed of a polyhedral oligosilsesquioxane represented by (iBuSiO _1.5 ) ₈ containing 640 ppm of potassium atoms in the form of potassium hydroxide was treated in the same manner as in Example 2. A white powder was obtained.
The content of potassium atom in this silicon compound was 0.26 ppm according to ICP-MS analysis.

  The present invention can be suitably used for producing a high-purity polyhedral oligosilsesquioxane suitable for a functional polymer material, particularly a polymer material for electronic materials.

Claims (23)

A method for purifying a polyhedral oligosilsesquioxane represented by the general formula (1) or (2) containing an alkali metal compound,
(RSiO _3/2 ) _n (1)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
(In the general formulas (1) and (2), R is selected from a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and a silicon atom-containing group having 1 to 3 silicon atoms. R may be the same or different. In general formula (2), Xa is a group selected from OH and the group defined by R, and a plurality of Xa may be the same or different. A plurality of Xa in (RXaSiO) _k may be connected to each other to form a connection structure, n is an integer from 6 to 14, l is an integer from 2 to 10, and k is an integer from 2 to 4. Yes, the total number of carbon atoms in general formula (1) is in the range of n to n × 12, and the total number of carbon atoms in general formula (2) is in the range of (l + k) to (l + k) × 12. Within.)
(1) A composition containing both at least a polyhedral oligosilsesquioxane and an alkali metal compound is brought into contact with a hydrophobic organic solvent having a water solubility at 20 ° C. of 1.0% by weight or less to form a hydrophobic organic A step of dissolving polyhedral oligosilsesquioxane in a solvent and obtaining an organic phase containing a fine particle dispersion; and (2) an organic phase containing the polyhedral oligosilsesquioxane obtained in the previous step and the fine particle dispersion. And a step of separating the fine particle dispersion from the polyhedral oligosilsesquioxane.   The method for purifying polyhedral oligosilsesquioxane according to claim 1, wherein the step (2) of separating the fine particle dispersion is a filtration treatment step.   The method for purifying polyhedral oligosilsesquioxane according to claim 2, wherein the filtration treatment step is a filtration treatment step using a hydrophobic filter.   The method for purifying polyhedral oligosilsesquioxane according to claim 3, wherein the hydrophobic filter is a hydrophobic membrane filter having an average pore size of 0.005 µm or more and 100 µm or less.   The polyhedron according to any one of claims 1 to 4, wherein the hydrophobic organic solvent used in the step (1) is an organic solvent having a water solubility at 20 ° C of 0.5% by weight or less. Purification method of oligosilsesquioxane. The method for purifying a polyhedral oligosilsesquioxane according to claim 1, wherein the polyhedral oligosilsesquioxane is a silanol compound represented by the general formula (3).
(R ¹ SiO _3/2 ) _l (R ¹ (OH) SiO) _k (3)
(In the general formula (3), R ¹ is selected from a hydrogen atom and a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ¹ may be the same or different, and l is 2 The integer of from 10 to 10 and k is the integer of from 2 to 4, and the total number of carbon atoms in the general formula (3) is in the range of (l + k) to (l + k) × 12.) The method for purifying a polyhedral oligosilsesquioxane according to claim 6, wherein the silanol compound represented by the general formula (3) has a structure represented by the general formula (4) or (5).
(R ¹ SiO _3/2 ) ₄ (R ¹ (OH) SiO) ₃ (4)

(R ^{1 in} general formulas (4) and (5) is the same as R ¹ in general formula (3). In general formula (5), R ¹ group bonded to the same silicon atom is OH groups may be exchanged for each other.) The method for purifying a polyhedral oligosilsesquioxane according to any one of claims 1 to 7, wherein R and R ¹ are groups selected from hydrocarbon groups having 2 to 10 carbon atoms.   The method for purifying a polyhedral oligosilsesquioxane according to claim 8, wherein the hydrocarbon group is a branched hydrocarbon group having 3 to 10 carbon atoms.   The method for purifying polyhedral oligosilsesquioxane according to claim 9, wherein the branched hydrocarbon group is an isobutyl group.   11. The polyhedral oligosilsesquioxane according to claim 1, wherein the composition used in the step (1) contains 80 wt% or more of polyhedral oligosilsesquioxane. Purification method.   In step (1), an aqueous dispersion composition containing at least both a polyhedral oligosilsesquioxane and an alkali metal compound is contacted with a hydrophobic organic solvent, and the polyhedral oligosilsesquioxane is extracted into the hydrophobic organic solvent. The method for purifying a polyhedral oligosilsesquioxane according to any one of claims 1 to 10, which is a step of obtaining an organic phase by separating the phase into an organic phase and an aqueous phase.   The method for purifying a polyhedral oligosilsesquioxane according to any one of claims 1 to 12, wherein the solution containing the polyhedral oligosilsesquioxane obtained in step (2) is further added to the polyhedral oligosilsesquioxane. A method for purifying polyhedral oligosilsesquioxane, wherein a step of precipitating polyhedral oligosilsesquioxane is added by adding a poor solvent of Sun. A) A polyhedral oligo represented by the general formula (1) by reaction with a basic alkali metal compound using at least one silicon compound selected from the compound represented by the general formula (6) and a condensate thereof as a raw material A process of producing silsesquioxane and B) a purification process of polyhedral oligosilsesquioxane represented by the general formula (1) according to any one of claims 1 to 5 and 8 to 13 are combined. A method for producing a high-purity polyhedral oligosilsesquioxane, which is characterized in that:
RSiXb ₃ (6)
(RSiO _3/2 ) _n (1)
(In General Formula (6), R is the same as defined in General Formula (1), and Xb is a group selected from an OH group, a halogen atom, and an —OQ group (Q is a hydrocarbon group having 1 to 10 carbon atoms). A plurality of Xb may be the same or different, and in general formula (1), R represents a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and the number of silicon atoms; Selected from 1 to 3 silicon atom-containing groups, a plurality of Rs may be the same or different, n is an integer from 6 to 14, and the total number of carbon atoms in general formula (1) is n to n Within the range of x12.) A ′) A polyhedron represented by the general formula (2) by reaction with a basic alkali metal compound using at least one silicon compound selected from the compound represented by the general formula (6) and the condensate thereof as a raw material A process for producing an oligosilsesquioxane (in the case of producing a polyhedral oligosilsesquioxane in which at least one of Xa in the general formula (2) is an OH group) And a process for producing a polyhedral oligosilsesquioxane represented by the general formula (2)), and B ′) represented by the general formula (2) according to any one of claims 1 to 13. A method for producing a high-purity polyhedral oligosilsesquioxane, which is combined with a purification step of a polyhedral oligosilsesquioxane.
RSiXb ₃ (6)
(RSiO _3/2 ) _l (RXaSiO) _k (2)
(In General Formula (6), R is the same as defined in General Formula (2), and Xb is a group selected from an OH group, a halogen atom, and an —OQ group (Q is a hydrocarbon group having 1 to 10 carbon atoms). A plurality of Xb may be the same or different, and in general formula (2), R is a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and the number of silicon atoms; Selected from 1 to 3 silicon atom-containing groups, a plurality of R may be the same or different, and Xa in the general formula (2) is a group selected from OH and the group defined by R; A plurality of Xa may be the same or different, and a plurality of Xa in (RXaSiO) _k may be connected to each other to form a connection structure, l is an integer of 2 to 10, and k is 2 To an integer from 4 to the total number of carbon atoms in general formula (2) Is in the range of (l + k) to (l + k) × 12.) The compound represented by the general formula (6) is a compound represented by the general formula (7), and the polyhedral oligosilsesquioxane to be produced and purified is a silanol compound represented by the general formula (8). The method for producing a high-purity polyhedral oligosilsesquioxane according to claim 15, wherein
R ² SiXc ₃ (7)
(R ² SiO _3/2 ) _l (R ² (OH) SiO) _k (8)
(R ² in the general formulas (7) and (8) is a hydrocarbon group having 2 to 10 carbon atoms, and a plurality of R ² in the general formula (8) may be the same or different. Xc in C) is an alkoxyl group having 1 to 4 carbon atoms or a chlorine atom, Xc may be composed of a plurality of groups selected from these groups, l is an integer of 2 to 10, and k is from 2 It is an integer of 4.) The compound represented by the general formula (8) has a structure represented by the general formula (9) or the general formula (10), and the production of the high purity polyhedral oligosilsesquioxane according to claim 16 Method.
(R ³ SiO _3/2 ) ₄ (R ³ (OH) SiO) ₃ (9)

(R ^{3 in} general formulas (9) and (10) is the same as R ² in general formula (8). In general formula (10), R ³ group bonded to the same silicon atom and OH groups may be exchanged for each other.) The method for producing a high-purity polyhedral oligosilsesquioxane according to claim 17, wherein R ³ is an isobutyl group.   Step A ′) for producing polyhedral oligosilsesquioxane is a step of reacting A′-1) raw material silicon compound and alkali metal hydroxide in the presence of water in the range of 30 to 300 ° C., and A '-2) The method for producing a high-purity polyhedral oligosilsesquioxane according to any one of claims 15 to 18, comprising a step of treating the reaction mixture produced in the previous step with an acid.   The method for producing a high purity polyhedral oligosilsesquioxane according to claim 19, wherein the reaction temperature in step A'-1) is 70 to 200 ° C.   The method for producing a high purity polyhedral oligosilsesquioxane according to claim 19 or 20, wherein the alkali metal hydroxide used in step A'-1) is lithium hydroxide.   The acid used in step A ′) or step A′-2) is an acid having a pKa (logarithm of the reciprocal of the acid dissociation constant) at −25 ° C. in an aqueous solution in the range of −2.0 to +5.5. The method for producing a high-purity polyhedral oligosilsesquioxane according to any one of claims 15 to 21, characterized in that:   The method for producing a high-purity polyhedral oligosilsesquioxane according to claim 22, wherein the acid is acetic acid.