CN101585850A - Aromatic cyanate ester monomer containing silicon and preparation method thereof - Google Patents

Abstract

The invention provides a silicon-containing aromatic cyanate monomer and a preparation method thereof. The structure of the cyanate resin monomer is as above: in the formula, n is an integer between 2 and 4. They use chlorosilane as the starting material to synthesize silicon-containing aromatic polyphenol monomers, and then react with cyanogen halides. The silicon-containing aromatic cyanate monomer of the present invention has very high reactivity, and the prepared resin has good thermal oxidation resistance and moisture resistance, and is suitable as a matrix of a new high-performance polymer composite material. In the fields of printed circuit boards and aerospace materials, especially the multifunctional resins, because of its unique space network structure, it is especially suitable for the fields of low dielectric constant materials and porous materials.

Description

A kind of silicon-containing aromatic cyanate monomer and preparation method thereof

technical field

The invention relates to a cyanate monomer and a preparation method thereof, in particular to a silicon-containing aromatic cyanate monomer and a preparation method thereof.

technical background

Cyanate resin is a new type of resin matrix containing two or more cyanate functional groups (-O-C≡N), which has the characteristics of excellent heat resistance, low toxicity and low moisture absorption of polyimide , and can be cured and molded by a molding process similar to that of epoxy resin, and the monomer or prepolymer does not emit volatile components during curing. This high-performance thermosetting resin has excellent properties such as high glass transition temperature, low dielectric constant and dielectric loss, small thermal expansion coefficient, and high bonding strength to metals. It is widely used in the fields of electronics, aviation, and adhesive industries. Compared with other resin matrices such as polymaleimide, epoxy resin, etc., cyanate resin has better toughness, but many of its other properties, such as fracture resistance, need to be improved. Many additives, including thermoplastic resins, epoxy resins, etc. , Bismaleimide, etc. are used for their toughening, but it will always reduce one or more of the key physical properties. Therefore, it is of great significance to create new monomer structures.

The introduction of heteroatom silicon into organic polymers is an important bridge connecting organic materials and inorganic materials. This method of atomic size tailoring will endow them with some unique and superior physical properties, which is an important means to improve material performance. U.S. Patents 5,260,389, 5,504,374, and 7,387,841 disclose a method for preparing aromatic cyanate esters containing short-chain siloxane structures. Compared with other corresponding cyanate resins, they have good fluidity due to the presence of silicon atoms Sex, superior flame retardancy, lower dielectric constant, good bonding performance, lower water absorption. In recent years, the introduction of aryl silicon structures in the main chain of linear polymers has aroused widespread interest. They can significantly increase the solubility and lower the melting point of materials, especially the electron delocalization characteristics of aromatic silicon-carbon bonds, which endow This material has better thermal stability than pure carbon-carbon bond materials (Macromolecules, 2001, 34, 3607; Macromolecules, 2003, 36, 8225). However, there are no reports of cyanate ester compounds with aryl silicon structure.

Contents of the invention

The technical problem to be solved by the present invention is to provide a silicon-containing aromatic cyanate monomer and a preparation method thereof.

A kind of phenolphthalein type cyanate monomer of the present invention has following structure:

In the formula, n is an integer between 2 and 4.

The synthesis of the present invention comprises three steps of preparing silicon-containing aromatic polybromine, silicon-containing aromatic polyphenol and silicon-containing aromatic cyanate, and the synthetic route is as follows:

Preparation of silicon-containing aromatic polybromine:

Dissolve 1,4-p-dibromobenzene in an organic solvent to make a 2% to 30% solution, and slowly add n-butyllithium n-hexane solution dropwise under nitrogen protection at -78°C to 25°C, 1,4 - The molar ratio of p-dibromobenzene to n-butyllithium is 1:1 to 1:3; after the addition of n-butyllithium, continue to stir for 2 hours, and then slowly add chlorosilane to make the mole ratio of bromine atom to chlorine atom The ratio is 0.1:1 to 1:0.1. After the dropwise addition, the reaction is continued for 0.5 to 6 hours, and then the reaction is terminated with dilute hydrochloric acid aqueous solution; static liquid separation, the organic phase is dried with anhydrous magnesium sulfate, filtered, and recrystallized to obtain the product.

The chlorosilane used in the above reaction is diphenylchlorosilane, phenyltrichlorosilane or silicon tetrachloride; the solvent is diethyl ether, petroleum ether, tetrahydrofuran, dioxane and mixtures thereof.

Preparation of silicon-containing aromatic polyphenols:

Dissolve the silicon-containing aromatic polybrominated product obtained in the above step (1) in an organic solvent to form a 5% to 30% solution, slowly add n-butyl lithium in n-hexane solution dropwise at -78°C to 25°C, bromine The molar ratio of atom to n-butyllithium is 1:1 to 1:5; after the dropwise addition, borate is slowly added dropwise, and the molar ratio of bromine atom to borate group is 1:1 to 1:5; After reacting for 0.5 to 24 hours under the protection of nitrogen, add alkali aqueous solution and 30% hydrogen peroxide aqueous solution successively, make the molar ratio of bromine atom and alkali be 1:1 to 1:4, the molar ratio of bromine atom and hydrogen peroxide is 1:1 to 1:20, continue the reaction for 1 to 5 hours, then add dilute hydrochloric acid aqueous solution to make the reaction system acidic, after static liquid separation, the organic phase is dried with anhydrous magnesium sulfate, filtered, and recrystallized to obtain the product.

The borates used in the above reaction include trimethyl borate, triethyl borate, triisopropyl borate; the base used in the above reaction includes organic amine, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate , Potassium bicarbonate and mixtures thereof; Reaction solvents include ether, petroleum ether, tetrahydrofuran, dioxane and mixtures thereof.

Preparation of silicon-containing aromatic cyanate

Dissolve cyanogen halide in organic solvent, and then add the mixed solution of silicon-containing aromatic polyphenol and acid-binding agent, or first dissolve silicon-containing aromatic polyphenol in organic solvent, and then add cyanogen halide and acid-binding agent in sequence. The molar ratio of silicon-containing aromatic polyphenol to cyanogen halide functional group is 1:1 to 1:10, and the functional group molar ratio of silicon-containing aromatic polyphenol to acid-binding agent is 1:1 to 1:5. The reaction temperature is -30°C to 50°C, and the reaction time is 0.5 to 24 hours. After the reacted mixed solution is filtered, it settles in a settling agent, and this settling agent includes n-hexane, cyclohexane, petroleum ether, diethyl ether and mixtures thereof. The precipitated product is recrystallized in an organic solvent, and the recrystallized organic solvent includes chloroform, dichloromethane, diethyl ether, petroleum ether, ethyl acetate and mixtures thereof. The organic solvents used in the preparation of silicon-containing aromatic cyanates include ethyl acetate, benzene, toluene, petroleum ether, diethyl ether, acetone, chloroform, 1,1,2-trichloroethane, dichloromethane and mixtures thereof.

The acid-coating agent used for the above-mentioned preparation of silicon-containing aromatic cyanate can be an alkali, including an organic base or an inorganic base, such as sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, sodium methylate, Potassium methoxide and various amines, such as triethylamine, diethylpropylamine, pyridine.

The cyanogen halide used in the above preparation of silicon-containing aromatic cyanate is cyanogen chloride or cyanogen bromide.

The cyanate ester described in the present invention is a cyanate ester containing a tetraaryl silicon structure, which may be a difunctional compound, or a trifunctional or tetrafunctional compound. The monomer has high activity, and the cured product has good thermal stability, thermal oxidation resistance, high glass transition temperature and low water absorption, making this cyanate ester resin suitable as a new high-performance The matrix of polymer materials is used in the fields of printed circuit board matrix and high toughness structural composite material matrix for aerospace, especially the multifunctional resin, because of its unique space network structure, it is especially suitable for low dielectric constant materials and porous materials.

Detailed ways

Example 1

Synthesis of bis(4-bromophenyl)disilane: Dissolve 25g of 1,4-p-dibromobenzene in 80ml of tetrahydrofuran, cool down to -78°C, and slowly add 31.2ml of 2.5N n-butyllithium n-hexane solution dropwise After the dropwise addition was completed and stirring was continued for 0.5 hours, 2.4 ml of diphenyldichlorosilane was added dropwise, and after the dropwise addition was completed, the reaction was continued for 5 hours, and the reaction was terminated with dilute hydrochloric acid aqueous solution. The organic phase was separated, dried with anhydrous magnesium sulfate, and the solvent was spin-dried, and the residue was recrystallized with ethyl acetate to obtain 14 g of white crystals with a yield of 87.4%.

Synthesis of bis(4-hydroxyphenyl)disilane: Dissolve 1.9g of bis(4-bromophenyl)disilane in 40ml of tetrahydrofuran, cool to -78°C, slowly add dropwise 3.7ml of 2.5N n-butyllithium n-hexane solution, after the dropwise addition, add 3.5ml of trimethyl borate dropwise, continue stirring for 3 hours after the dropwise addition, add 6ml of 3M aqueous sodium hydroxide solution and 2ml of 30% hydrogen peroxide, stir and react for 3 hours, then adjust with hydrochloric acid aqueous solution to acidic. After static liquid separation, the organic phase was dried with anhydrous magnesium sulfate and the solvent was spin-dried, and the residue was recrystallized with chloroform to obtain 0.59 g of white crystals with a yield of 68.2%.

Synthesis of bis(4-cyanatophenyl)diphenylsilane: Dissolve bis(4-hydroxyphenyl)diphenylsilane (3.68g, 10mmol) in 30ml acetone, cool to -5°C, add Cyanogen bromide (3.48g, 30mmol) and triethylamine (5.6ml, 20mmol) were stirred for 4 hours to terminate the reaction. The above mixture was filtered through a large amount of cyclohexane to obtain a crude product, which was recrystallized with 60-90°C petroleum ether, filtered and dried to obtain 3.95 g of cyanate, with a yield of 94.5%.

Infrared spectrum (potassium bromide tablet method, cm ^-1 ): 3035, 2270, 2234, 1598, 1499, 1451;

Proton NMR spectrum (400MHz, DMSO-d6): δ (ppm): 7.77 (d, 4H), 7.53 (d, 8H), 7.36 (m, 6H).

Example 2

Synthesis of tris(4-bromophenyl)phenylsilane: Dissolve 18g of 1,4-p-dibromobenzene in 80ml of tetrahydrofuran, cool to -78°C, slowly add 47.4ml of 2.5N n-butyl lithium in n-hexane After the solution was continuously stirred for 4 hours after the dropwise addition, 1.5 ml of phenyltrichlorosilane was added dropwise. After the dropwise addition, the reaction was continued for 2 hours, and the reaction was terminated with dilute hydrochloric acid aqueous solution. The organic phase was separated, dried with anhydrous magnesium sulfate, and the solvent was spin-dried, and the residue was recrystallized with dichloromethane to obtain 2 g of white crystals with a yield of 89.2%.

Synthesis of tris(4-hydroxyphenyl)phenylsilane: Dissolve 2.3g of tetrakis(4-bromophenyl)silane in 50ml of tetrahydrofuran, cool to -78°C, slowly add 9.3ml of 2.5N n-butyl lithium dropwise n-Hexane solution, after the dropwise addition, add 2.5ml triisopropyl borate dropwise, continue stirring for 3 hours after the dropwise addition, add 12ml 3M aqueous sodium hydroxide solution and 5ml 30% hydrogen peroxide, and stir for 4 hours, then use hydrochloric acid aqueous solution Adjust to acidic. After static liquid separation, the organic phase was dried with anhydrous magnesium sulfate and the solvent was spin-dried, and the residue was recrystallized with ethyl acetate to obtain 1.21 g of white crystals with a yield of 69.9%.

Synthesis of tris(4-cyanatophenyl)phenylsilane: Dissolve tris(4-hydroxyphenyl)phenylsilane (3.84g, 10mmol) in 40ml acetone, cool to -5°C, add brominated Cyanogen (4.24g, 40mol) and triethylamine (8.4ml, 30mol) were stirred for 4 hours to terminate the reaction. The above mixture was filtered through a large amount of cyclohexane to settle and filter to obtain a crude product, which was recrystallized with 60-90°C petroleum ether, filtered and dried to obtain 4.1 g of cyanate ester with a yield of 94.4%.

Infrared spectrum (potassium bromide tablet method, cm- ¹ ): 3032, 2272, 2238, 1599, 1494, 1451;

Proton NMR spectrum (400MHz, DMSO-d6): δ (ppm): 7.77 (d, 6H), 7.52 (d, 8H), 7.36 (m, 3H).

Example 3

Synthesis of tetrakis(4-bromophenyl)silane: Dissolve 25g of 1,4-p-dibromobenzene in 80ml of tetrahydrofuran, cool to -78°C, slowly add 63.2ml of 2.5N n-hexane solution of n-butyl lithium dropwise, After the dropwise addition was completed and stirring was continued for 1 hour, 2.5 ml of tetrachlorosilane was added dropwise, and the reaction was continued for 2 hours after the dropwise addition, and the reaction was terminated with dilute hydrochloric acid aqueous solution. The organic phase was separated, dried with anhydrous magnesium sulfate, and the solvent was spin-dried, and the residue was recrystallized with dichloromethane to obtain 16 g of white crystals with a yield of 93.7%.

Synthesis of tetrakis(4-hydroxyphenyl)silane: Dissolve 1.3g of tetrakis(4-bromophenyl)silane in 50ml of tetrahydrofuran, cool to -78°C, slowly add 7.3ml of 2.5N n-butyl lithium in n-hexane Solution, after the dropwise addition, add 3.5ml trimethyl borate dropwise, continue to stir for 3 hours after the dropwise addition, add 10ml 3M aqueous sodium hydroxide solution and 3ml 30% hydrogen peroxide, stir and react for 5 hours, then adjust to acidity with aqueous hydrochloric acid solution . After static liquid separation, the organic phase was dried with anhydrous magnesium sulfate and the solvent was spin-dried, and the residue was recrystallized with ethyl acetate to obtain 0.51 g of white crystals, with a yield of 63.2%.

Synthesis of tetrakis(4-cyanatophenyl)silane: Dissolve 4g of tetrakis(4-hydroxyphenyl)silane in 50ml of acetone, cool to -5°C, add 5.52g of cyanogen bromide and 11.2ml of triethylamine , stirring the reaction for 4 hours to terminate the reaction. The above mixture was filtered through a large amount of cyclohexane to obtain a crude product, which was recrystallized with 60-90°C petroleum ether, filtered and dried to obtain 4.2 g of cyanate ester, with a yield of 88.4%.

Infrared spectrum (potassium bromide tablet method, cm ^-1 ): 3030, 2271, 2235, 1594, 1501, 1451;

Proton NMR spectrum (400MHz, DMSO-d6): δ (ppm): 7.76 (s, 8H), 7.55 (d, 8H).

Claims (4)

1. an aromatic cyanate ester monomer containing silicon is characterized in that, this aromatic cyanate ester monomer containing silicon has following structural formula:

N is the integer between 2 to 4 in the formula.

2. one kind prepares the method for cyanate ester monomer according to claim 1, it is characterized in that synthetic three steps that it comprises the many bromines of siliceous fragrance, siliceous fragrant polyphenol and siliceous aromatic cyanate ester:

The preparation of the many bromines of siliceous fragrance:

With 1, the 4-paradibromobenzene is dissolved in and is made into 2% to 30% solution in the organic solvent, and at-78 ℃ to 25 ℃, nitrogen protection slowly drips the hexane solution of n-Butyl Lithium down, and 1, the mol ratio of 4-paradibromobenzene and n-Butyl Lithium is 1: 1 to 1: 3; N-Butyl Lithium dropwises the back to be continued to stir 2 hours, slowly drips chlorosilane again, and making the mol ratio of bromine atoms and chlorine atom is 0.1: 1 to 1: 0.1, dropwises back continuation reaction and uses the diluted hydrochloric acid aqueous solution termination reaction after 0.5 to 6 hour; Static separatory, organic phase obtain product after with anhydrous magnesium sulfate drying, filtration, recrystallization; The chlorosilane that uses in the above-mentioned reaction is diphenyl chlorosilane, phenyl-trichloro-silicane or silicon tetrachloride; Preparing the used organic solvent of the many bromines of siliceous fragrance is ether, sherwood oil, tetrahydrofuran (THF), dioxane and composition thereof;

The preparation of siliceous fragrant polyphenol:

Siliceous many bromines of fragrance product that above-mentioned steps (1) is obtained is dissolved in and is made into 5% to 30% solution in the organic solvent,? 8 ℃ to the 25 ℃ hexane solutions that slowly drip n-Butyl Lithium down, the mol ratio of bromine atoms and n-Butyl Lithium is 1: 1 to 1: 5; Slowly drip boric acid ester after dropwising again, the mole number of bromine atoms and boric acid ester group is 1: 1 to 1: 5; Reaction is after 0.5 to 24 hour under nitrogen protection, successively add alkali aqueous solution and 30% aqueous hydrogen peroxide solution, the mol ratio that makes bromine atoms and alkali is 1: 1 to 1: 4, the mol ratio of bromine atoms and hydrogen peroxide is 1: 1 to 1: 20, continuing reaction adds diluted hydrochloric acid aqueous solution to make reaction system is acid after 1 to 5 hour, behind the static separatory, organic phase gets product with anhydrous magnesium sulfate drying, filtration, recrystallization; The boric acid ester that above-mentioned reaction is adopted is a trimethyl borate, triethyl borate or triisopropyl borate ester; The alkali that above-mentioned reaction is adopted comprises organic amine, sodium hydroxide, potassium hydroxide, yellow soda ash, salt of wormwood, sodium bicarbonate, saleratus and composition thereof; Preparing the used organic solvent of siliceous fragrant polyphenol is that solvent is ether, sherwood oil, tetrahydrofuran (THF), dioxane and composition thereof;

The preparation of siliceous aromatic cyanate ester

Halogen cyan is dissolved in organic solvent, adds the mixing solutions of siliceous fragrant polyphenol and acid binding agent again; Or siliceous fragrant polyphenol is dissolved in earlier in the organic solvent, add halogen cyan and acid binding agent more successively; Functional group's mol ratio of wherein siliceous fragrant polyphenol and halogen cyan is 1: 1 to 1: 10, and functional group's mol ratio of siliceous fragrant polyphenol and acid binding agent is 1: 1 to 1: 5; Temperature of reaction is-30 ℃ to 50 ℃, and the reaction times is 0.5 to 24 hour; Reacted mixing solutions is filtered back sedimentation in sinking agent, and this sinking agent comprises normal hexane, hexanaphthene, sherwood oil, ether and composition thereof; Sedimentation products is recrystallization in organic solvent, and the organic solvent of recrystallization comprises chloroform, methylene dichloride, ether, sherwood oil, ethyl acetate and composition thereof; Preparing the used organic solvent of siliceous aromatic cyanate ester is ethyl acetate, benzene, toluene, sherwood oil, ether, acetone, chloroform, vinyl trichloride, methylene dichloride and composition thereof.

3. preparation method as claimed in claim 2, its feature are that also preparing the used acid-binding agent of siliceous aromatic cyanate ester is alkali, comprises organic bases or mineral alkali.

4. preparation method as claimed in claim 2, its feature are that also preparing the used halogen cyan of siliceous aromatic cyanate ester is mauguinite or cyanogen bromide.