JP2002363287A - Method for producing novel silsesquioxane having protected catechol group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silsesquioxane having a catechol group protected with an organic substituent. SOLUTION: This method for producing a novel silsesquioxane having a protected catechol group is to carry out reactions of hydrolysis and dehydration- condensation by using a compound expressed by formula [1] (wherein, R1 , R2 and R3 represent each a 1-6C alkoxy or chlorine and may be the same or different; R4 represents a 2-6C alkylene; R5 and R6 represent each a 1-6C alkyl or phenyl and may be the same or different).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a production method for carrying out a hydrolysis / dehydration condensation reaction using an organic silicon compound having three alkoxy groups in a molecule as a raw material. The compound obtained according to the present invention is a novel silsesquioxane having a protected catechol group.

[0002]

2. Description of the Related Art Silsesquioxane has a random structure,
It is a general term for network-like polysiloxanes having various structures such as a ladder structure and a cage structure (T8, T10, T12, etc.) (for example, RH Baney, et al. Chem. Rev., 95, 140).
9 (1995)) and several examples of introducing various functional groups into silsesquioxane have been known so far. As an example of introducing a polar functional group, silsesquioxane having a protected phenol is known [JP-A-6-18431.
1]. Silsesquioxane having a protected catechol group is expected to exhibit excellent properties such as alkali solubility, chemical reactivity and hydrogen bonding from its chemical structural formula, but production examples are still unknown. Absent.

[0003]

It is an object of the present invention to provide a process for the preparation of silsesquioxanes having a catechol group protected by an organic substituent, whereby alkali-soluble, chemically reactive or hydrogen-bonded compounds are obtained. It is intended to contribute to the production of an organic-inorganic hybrid material exhibiting properties.

[0004]

[Means for Solving the Problems]

The present inventors have conducted intensive studies on a method for producing silsesquioxane having a protected catechol group, and as a result, have completed the present invention. That is, the present invention is a novel method for producing silsesquioxane, which comprises performing a hydrolysis and dehydration condensation reaction using a compound represented by the following structural formula (1) as a raw material.

[0006]

Embedded image

Wherein R ₁ , R ₂ and R ₃ are an alkoxy group having 1 to 6 carbon atoms or chlorine, which may be the same or different, and R ₄ is a group having 2 to 6 carbon atoms. An alkylene group, and R ₅ and R ₆ are an alkyl group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different.)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the production method of the present invention, hydrolysis and dehydration condensation are carried out using a novel organosilicon compound represented by the general formula [1] (hereinafter abbreviated as organosilicon compound [1]) as a raw material. . In the above general formula [1], R ₁ , R ₂ and R ₃ are an alkoxy group having 1 to 6 carbon atoms or chlorine, and preferred specific examples of the alkoxy group include a methoxy group, an ethoxy group,
Examples thereof include a propyloxy group, a butyloxy group, a pentyloxy group, and a hexyloxy group, which may be linear or branched. In the general formula [1], R ₄ is an alkylene group having 2 to 6 carbon atoms, which may be linear or branched. Specific examples include a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, There are a hexamethylene group, a 2-methyltrimethylene group and a 3-methyltrimethylene group. R ₅ and R ₆ have 1 to 6 carbon atoms
Preferred specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a phenyl group.
It may be linear or branched. R ₅ and R ₆ may be cyclic. R _{1 to} R ₆ are preferably an ethoxy group for R ₁ , R ₂ and R ₃ , and a carbon number for R ₄ because R _{1 to} R ₆ are easy to synthesize the compound represented by the general formula [1]. Is a linear hydrocarbon of 3, and R ₅ and R ₆ are methyl groups.

The position of the alkoxysilyl group may be either the ortho position or the meta position with respect to the catechol group protected by the organic substituent. The preferred organosilicon compound [1] in the present invention is a compound [2] represented by the following structural formula (hereinafter referred to as TESCA).

[0010]

Embedded image

The method for producing the organosilicon compound [1] The organosilicon compound [1] in the present invention is a novel compound.
(3) It can be easily manufactured. Step (1): A compound [3] represented by the following formula [3] is obtained by reacting trihydroxybenzene having at least two hydroxyl groups at the ortho position with a compound for protecting a catechol group.

[0012]

Embedded image

(In the formula, R ₅ and R ₆ have the same meanings as in the above general formula [1].)

Step (2): The above compound [3] and a halogenated alkene (provided that they have the same carbon skeleton as R ₄ in the above general formula [1] except for having a carbon-carbon double bond at one molecular terminal) Has a halogen at the other molecular end.)
To obtain a compound [4] represented by the following formula [4].

[0015]

Embedded image

(In the formula, R ₇ is a residue obtained by removing a halogen in a halogenated alkene, and has a carbon-carbon double bond at a terminal.)

Step (3): silanization with the above compound [4]
Compound R₁R_TwoR_ThreeSiH (however, R₁, R _TwoAnd R_ThreeIs above
It has the same meaning as in general formula [1]. ) And the hydro
The compound of the above general formula [1] is reacted by a silylation reaction.
obtain.

Hereinafter, the respective reaction steps (1) to (3) will be described in more detail. [Step (1)] Trihydroxybenzene in the step (1) has at least two hydroxyl groups at the ortho position, and preferable examples include pyrogallol and 1,2,4-trihydroxybenzene. The compound for protecting a catechol group is a compound having a reactive group for R ₅ , R ₆ and a catechol group in a molecule (provided that R ₅ and R ₆ have the same meanings as in the above formula [1]. the same.). When R ₅ and R ₆ are alkyl groups, a preferred reactive group for the catechol group is an alkoxy group, and a more preferred reactive group is a methoxy group. When R ₅ or R ₆ is a phenyl group, the preferred reactive group for the catechol group is halogen, more preferably chlorine. The following compounds are preferable as the compound for protecting the catechol group,

[0019]

Embedded image

[0020]

Embedded image

Examples are 2,2-dimethoxybutane, 3,2
Examples include 3-dimethoxypentane, 5,5-dimethoxynonane, diphenyldichloromethane, and the like.

The reaction in the step (1) is carried out by adding a solvent to trihydroxybenzene and dropping a compound for protecting a catechol group under reflux with heating. Although this reaction is an equimolar reaction between trihydroxybenzene and a compound for protecting a catechol group, a part thereof is distilled out of the reaction system together with a by-produced alcohol, so that the latter is usually supplied in excess to carry out the reaction. Alcohol or hydrogen halide by-produced in the reaction system is allowed to flow out of the reaction system to complete the reaction. Preferred solvents include hydrocarbons such as n-pentane, n-hexane, cyclohexane, petroleum ether, toluene, xylene, gasoline and ligroin; ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran. After the completion of the above reaction, the solvent and volatile components are distilled off under reduced pressure to obtain the following compound [3]. In this compound [3], the catechol group is protected by an organic substituent [(R ₅ ) (R ₆ ) C =].

[0023]

Embedded image

[Step (2)] The alkene halide in the step (2) has the same carbon skeleton as R ₄ in the above general formula [1] except that it has a carbon-carbon double bond at one molecular terminal. It is a compound having a halogen at the other molecular terminal. Preferred halogenated alkenes are 2-chloro-
1-ethene, 4-bromo-1-butene, 5-chloro-1
-Pentene, 6-chloro-1-hexene and the like. The reaction of the step (2) is performed by adding a solvent and a base to the compound [3] obtained in the step (1), and dropwise adding an alkene halide under reflux with heating.

Preferred solvents are alcohols such as methanol, ethanol, isopropanol and butanol, ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran, and polar solvents such as water, acetone and dimethylformamide. Preferred bases are sodium hydroxide, potassium hydroxide, potassium carbonate and the like. After the reaction of the compound [3] with the halogenated alkene is completed, the solvent and volatile components are distilled off under reduced pressure, and the following compound [4] is isolated by distillation under reduced pressure.

[0026]

Embedded image

[Step (3)] The reaction of the compound [4] obtained in the step (2) with the silane compound (R ₁ R ₂ R ₃ SiH) is usually carried out in the presence of a catalyst. As a preferred catalyst,
There is a simple substance of Group 8 to Group 10 metals such as cobalt, nickel, ruthenium, rhodium, palladium, iridium, platinum and the like, organometallic complexes, metal salts, metal oxides and the like. Of these, platinum-based catalysts are particularly preferred. The platinum-based catalyst, chloroplatinic acid hexahydrate _{(H 2 PtCl 6 · 6H 2} O), cis-
Examples include PtCl ₂ (PhCN) ₂ , platinum carbon, a platinum complex coordinated with divinyltetramethyldisiloxane (PtDVTMDS), and the like. Ph represents a phenyl group. The preferred amount of the catalyst used is 0.1 ppm to 1,000 p based on the amount of the compound [4].
pm.

The control operation of the reaction temperature depends on the external heating and the supply rate of the silane compound, and therefore cannot be unconditionally determined.
By keeping in the range, the hydrosilylation reaction can be smoothly continued. After completion of the reaction, the solvent and volatile components are distilled off under reduced pressure to obtain the compound of the above general formula [1].

Hydrolysis and dehydration condensation The target compound can be obtained by subjecting the organosilicon compound [1] to a known hydrolysis and dehydration condensation reaction. The hydrolysis / dehydration condensation reaction is preferably performed in the presence of a basic or acidic catalyst. Preferred basic catalysts include tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide and the like, and preferred acidic catalysts include hydrochloric acid, sulfuric acid and nitric acid. Preferred solvents used in the hydrolysis include alcohols such as methanol, ethanol, and isopropyl alcohol; and ketones such as acetone and ethyl methyl ketone. The reaction temperature differs depending on the type of the catalyst, and can be appropriately set according to a standard method. Specifically, the temperature when using a basic catalyst is from 10 ° C. to the boiling point of the solvent, and the temperature when using an acidic catalyst can be selected in an appropriate temperature range of room temperature or higher. However, when an acidic catalyst is used, if the reaction temperature is too high, the protected catechol group may be eliminated, so that such a high temperature must be avoided. The reaction time is generally 0.5 to 40 hours. A preferable addition ratio of water used for the hydrolysis reaction is 1.5 to 9 equivalents per equivalent of Si of the organosilicon compound [1]. The preferred pH at the time of the hydrolysis reaction is 1 to 5 (when an acidic catalyst is used) or 8 to 14 (when a basic catalyst is used). The number average molecular weight and the molecular structure of the silsesquioxane can be controlled by appropriately adjusting the concentration of the organosilicon compound [1] in the reaction vessel. 50% by weight.

The features of the silsesquioxane The novel silsesquioxane obtained by the present invention has the following features. -A three-dimensional network is formed by the following repeating units, and a random structure, a ladder structure, and a cage structure (T8, T10,
T12). The preferred number average molecular weight of the silsesquioxane is from 1,000 to 5
The preferred structure is a cage structure (T8).

[0031]

Embedded image

It is soluble in general-purpose solvents and is easy to handle as a raw material for various chemical reactions. Since it has a protected catechol group, it can be used for a reactive organic-inorganic hybrid material having heat resistance and decomposition resistance by potentially using an acid generator such as an onium salt. -For the organic group substituted for the hydroxyl group of the catechol group, select the hydrolysis conditions under acidic conditions (for example, if the temperature is 80 ° C).
As described above, the compound is easily eliminated, expresses free catechol, and functions as an alkali-soluble silsesquioxane. Free catechol is phenolic
Because it has twice as many hydroxyl groups, its alkali solubility is much better than silsesquioxane with protected phenol. -Free catechol forms a strong hydrogen bond with a polar functional group, so that it can form a crosslinked structure utilizing a hydrogen bond, and can be used for an organic-inorganic hybrid material having heat resistance and decomposition resistance. Free catechol is
Because it has twice as many hydroxyl groups as phenol, the density of crosslinks using hydrogen bonds is much higher than silsesquioxane with protected phenol.

[0033]

According to the present invention, a novel silsesquioxane having a protected catechol group can be easily obtained. The silsesquioxane obtained by the present invention can be used as a raw material for producing an organic-inorganic hybrid material exhibiting alkali solubility, chemical reactivity, or hydrogen bonding. Further, it can be used as a modifier for a resin, an agent for imparting alkali solubility, an agent for imparting heat resistance to a resin, a crosslinking agent utilizing hydrogen bonding, and the like.

[0034]

The present invention will be specifically described below with reference to examples.

Example 1 (Hydrolysis by acidic catalyst) TESCA was hydrolyzed under acidic conditions to obtain silsesquioxane as follows. After charging 6.5 ml of isopropyl alcohol and TESCA (5.0 g, 13 mmol) into a reactor equipped with a stirrer and a thermometer, a 35% aqueous solution of hydrogen chloride (hereinafter referred to as HCl) (0.034
g) and water (0.68 g) were gradually added, and the mixture was stirred and left at room temperature for 24 hours. At this time, the pH of the reaction system was 1.0, and the concentrations of hydrogen chloride and water were [HCl: 0.325 mmol, H ₂ O: 39 mmol], respectively. After the reaction was completed, 30 ml of toluene was added to the system, and the system was dehydrated with anhydrous sodium sulfate. The desired silsesquioxane was obtained by distilling off volatile components under reduced pressure. The number average molecular weight of this silsesquioxane was 1500 and the molecular weight distribution was 1.16. The ¹ H-NMR spectrum of the obtained silsesquioxane is shown in FIG. FIG. 2 shows the IR spectrum and Table 2 shows the assignment.

[0036]

[Table 1]

[0037]

Embedded image

[0038]

[Table 2]

Example 2 (Hydrolysis with basic catalyst) TESCA was hydrolyzed under basic conditions as follows.
Silsesquioxane was obtained. After 6.5 ml of isopropyl alcohol and TESCA (5.0 g, 13 mmol) were charged into a reactor equipped with a stirrer and a thermometer, 25% tetramethylammonium hydroxide “Me ₄ N
Aqueous solution (0.12 g), water (0.61 g) [Me ₄ NOH:
0.325 mmol, H ₂ O: 39 mmol] was gradually added, and the mixture was stirred and left at room temperature for 24 hours. At this time, the pH of the reaction system was 9.0 and Me ₄
The concentrations of NOH and water were [Me ₄ NOH: 0.325 mmol, H ₂ O: 39 mmol], respectively. After the completion of the reaction, 30 mL of toluene was added to the system, and the reaction solution was washed with saturated saline using a separating funnel. After repeatedly washing with water until the aqueous layer of the separating funnel becomes neutral, the organic layer is separated, dehydrated with anhydrous sodium sulfate, and the desired silsesquioxane is distilled off under reduced pressure to remove volatile components. I got The number average molecular weight of this silsesquioxane was 2500 and the molecular weight distribution was 1.25.

Example 3 (Hydrolysis by Basic Catalyst) The same procedure as in Example 2 was carried out except that an aqueous solution (0.24 g) of 25% Me ₄ NOH and water (0.52 g) were used. At this time, the pH of the reaction system was 9.0 and M
The concentrations of e ₄ NOH and water are respectively [Me ₄ NOH: 0.650 mmol, H ₂ O: 39 mmol]
Met. The number average molecular weight of this silsesquioxane is 29
00, molecular weight distribution was 1.29.

Example 4 (Hydrolysis by an acidic catalyst) Using a compound represented by the following structural formula in which the hydrolyzable functional group is chlorine (hereinafter abbreviated as TCSCA) as a raw material, the following acidic conditions were used. To give silsesquioxane.

[0042]

Embedded image

In a reactor equipped with a stirrer and a thermometer, 6.5 mL of isopropyl alcohol and TCSCA (5.0 g, 15 mmol) were added.
Was added, an aqueous solution (0.034 g) of 35% hydrogen chloride (hereinafter referred to as HCl) (0.034 g) and water (0.68 g) were gradually added, and the mixture was stirred at room temperature for 24 hours. At this time, the pH of the reaction system was 1.0, and the concentrations of hydrogen chloride and water were respectively [HCl: 0.325 mmol, H ₂ O: 3
9 mmol]. After the completion of the reaction, 30 mL of toluene was added to the system, and the system was dehydrated with anhydrous sodium sulfate. The desired silsesquioxane compound was obtained by distilling off volatile components under reduced pressure. The number average molecular weight of this silsesquioxane compound was 1,800, and the molecular weight distribution was 1.18.

[Brief description of the drawings]

FIG. 1 shows the ¹ H-NMR spectrum of the product obtained in Example 1.

FIG. 2 shows an IR spectrum of the product obtained in Example 1.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H049 VN01 VQ57 VQ79 VR21 VR33 VR43 VS01 VT03 VT16 VT17 VT23 VU16 VV05 VV07 4J035 BA12 CA07N CA071 EA01 EB02 LA05

Claims (2)

[Claims] 1. A novel method for producing silsesquioxane, which comprises subjecting a compound represented by the following structural formula [1] to a hydrolysis and dehydration condensation reaction as a raw material. Embedded image (Wherein R ₁ , R ₂ and R ₃ are an alkoxy group having 1 to 6 carbon atoms or chlorine, which may be the same or different, and R ₄ is an alkylene group having 2 to 6 carbon atoms) R ₅ and R ₆ are an alkyl group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different from each other.) 2. In the general formula [1] according to claim 1,
R ₁ , R ₂ and R ₃ are ethoxy groups, and R ₄ has 3 carbon atoms.
2. The novel silsesquioxane according to claim 1, wherein a compound represented by the following structural formula [2] is used as a raw material, wherein R ₅ and R ₆ are methyl groups. Manufacturing method. Embedded image