CN100509919C - Synthesis of boron-contained silicone - Google Patents

Abstract

Synthesis of boron-contained silicone is carried out by taking magnesium block as cathode-anode, polymerizing silane dihalide or allyl chloride trihalide in butylene oxide solution and synthesizing to obtain the final product. It's simple, safe and controllable. It has gentle reactive condition and decreases C/C composite material high-temperature anti-oxidant performance and can be used as ceramic precursor.

Description

The synthetic method of boron-contained silicone

Technical field

The present invention relates to the synthetic method of a kind of synthetic method of polysilane, particularly a kind of boron-contained silicone.

Background technology

Polysilane is the superpolymer of silicon atoms only in the class chain backbone, and its main chain is the Si-Si key.The non-localizedization of its Si-Si chain σ bonding electron makes Si-Si key σDian Zi to move along main chain and forms big conjugated system σ conjugated link(age).Its particular structure makes it present distinctive character at aspects such as solvability, thermostability, uv-absorbing, thermochromism and fluorescence.Based on its particular performances, have broad application prospects at aspects such as photo-resist, photoinitiators, wave guide, optical conductor and nonlinear optical materials, in addition, polysilane is as SiC, Si ₃N ₄Deng the precursor of pottery, preparing thyrite through Pintsch process is one of its purposes, mainly prepares fire-resistant oxidation resistant silicon carbide ceramics fiber, perhaps prepares C/C-SiC matrix material to improve the antioxidant property of C/C.Yet polysilane wishes to introduce atom or the atomic group with antioxidant property as ceramic precursor, to improve the resistance to elevated temperatures of C/C matrix material.。

Boron-contained silicone, owing to introduce the boron atom on the polysilane chain, the boron atom at first reacts with oxygen in well-oxygenated environment, forms B ₂O ₃At low temperatures, B ₂O ₃There are lower fusing point, comparatively ideal viscosity characteristics and C/C matrix material that good wettability is arranged; B ₂O ₃When high temperature, can regulate SiO ₂Viscosity, thereby the crackle that forms in the packing oxidising process, and SiO ₂Have low oxygen rate of diffusion and lower vapour pressure, can stop the infiltration of oxidizing atmosphere to carbon base body.Therefore, the introducing of boron atom can improve the antioxidant property of ceramic precursor effectively, and its development has important in theory meaning and actual value to the raising of the resistance to elevated temperatures of C/C matrix material.

In the research in early days, the technological line following to the synthetic employing of boron-contained silicone: the reaction of Wurtz reductive coupling takes place by the compound and the sodium Metal 99.5 of siliceous chlorine key and boron chlorine key in (1), be reflected in inert solvent such as toluene, the dimethylbenzene and carry out, treat the dechlorination polycondensation that heats up again after basic metal is dispersed in the solvent.(M.S.Hsu，T.S.Chen，andS.R.Riccitiello，J.Applied.Polym.Sci.1991，42，851)。(2) utilize the hydroboration of unsaturated organopolysilane such as dimethyl divinyl silane and borane compound to make boron-contained silicone.(S.R.Riccitiello，M.T.S.Hsu?and?T.S.Chen.US?Pat.US?4987201，January?1991.Riedel，R.；Kienzle，A.；Szabo，V.；Mayer，J.J.Mater.Sci.1993，28.3931-3938)

In said synthesis route, exist many problems: adopt the Wurtz reducing couple legal in the technological line (1), reaction conditions fierceness, speed of reaction are difficult to control, the implode phenomenon usually occurs.Because alkali-metal existence makes reaction have certain danger.Be unsuitable for the suitability for industrialized production of polysilane.Employed two kinds of unsaturated organopolysilanes of monomer and borane compound all do not have commodity production at home in the technological line (2).

Summary of the invention

The object of the present invention is to provide a kind of synthetic method of simple to operate, safe boron-contained silicone.

For achieving the above object, it is that monomer synthesizes boron-contained silicone with two halosilanes or three halosilanes and boron trifluoride diethyl etherate that the present invention adopts the electrochemical synthesis method, and its synthetic route is:

Or:

Wherein R is C ₁-C ₃Alkyl or phenyl; X represents that (Br I), is comparatively ideal as halogen atom Cl to halogen atom for Cl, F.

According to above-mentioned mechanism, the present invention adopts following technical scheme:

1. the synthetic method of a boron-contained silicone is characterized in that this method is is solvent with the tetrahydrofuran (THF), is monomer with two halosilanes or three halosilanes and boron trifluoride, synthesizes boron-contained silicone by electrochemical reaction; The general structure of two halosilanes or three halosilanes is:

Or

Wherein R is C ₁-C ₃Alkyl or phenyl; X represents halogen atom, and concrete steps are as follows:

A. being solvent with the tetrahydrofuran (THF), is that two halosilanes of 3～1:1 or three halosilanes and boron trifluoride ether solution are put into electrochemical reactor with mol ratio, adds the lithium perchlorate supporting electrolyte simultaneously, and the concentration of lithium perchlorate is 0.1mol/L-0.2mol/L;

B. under inert atmosphere, start and stir and ultrasonic wave, energising then begins reaction, and the energising electric energy control is at 1300mAh-1400mAh;

C. after reaction finishes, add toluene, feed ammonia again with dilution and dissolving macromole polysilane, to the reaction system in the remaining Si-Cl key and fully; Pass through press filtration and underpressure distillation then, obtain flaxen liquid boron-contained silicone.

Compared with prior art, the inventive method has following conspicuous outstanding feature and remarkable advantage: the boron-contained silicone that the inventive method obtains and the inventive method reaction conditions gentleness, easy to control, simple to operate, safety, prepared boron-contained silicone can improve the high-temperature oxidation resistance of C/C matrix material significantly, is a kind of ceramic precursor of excellent performance.The inventive method has solved the problem that exists in the early stage research effectively, helps the large-scale industry utilization.

Description of drawings

Fig. 1 is the infrared spectrogram of boron-contained silicone.

Fig. 2 is the ultraviolet spectrogram of boron-contained silicone.

Fig. 3 is a boron-contained silicone ¹³The C-NMR spectrogram.

Fig. 4 is the linear ablative rate of the C/C-B-SiC matrix material of continuous impregnating three times.

Fig. 5 is the mass ablative rate of the C/C-B-SiC matrix material of continuous impregnating three times.

Embodiment

Embodiment one: ventpipe is being housed, in the electrochemical reaction bottle of agitator and thermometer, is adding the methyl hydrogen dichlorosilane and the boron trifluoride ether solution of different mol ratio.The tetrahydrofuran (THF) (add a spot of sodium dehydration through distillation, get 66 ℃ of cuts) that adds then about 130ml is the lithium perchlorate (LiClO of 0.1mol/L with concentration ₄) as supporting ionogen.Make anode and cathode with MAG block.Through behind three vacuum nitrogen fillings, start and stir and ultrasonic wave, energising then begins reaction, reach and stop energising when the reaction electric weight reaches 1340mA*h, add 200ml toluene, feed an air bag ammonia, the Si-Cl key that neutralization is remaining, the variation of thermometer in the observing response bottle at this moment, along with the feeding temperature of ammonia increases, treat that the thermometer registration is steady, when no longer raising, temperature shows then that Si-Cl key remaining in the reaction system has neutralized fully; Through secondary press filtration and underpressure distillation, obtain flaxen liquid boron-contained silicone.Each constituent content sees Table 1 in the number-average molecular weight of the boron-contained silicone of used methyl hydrogen dichlorosilane and the mol ratio of boron trifluoride diethyl etherate and gained and the product.All about 400, distribution coefficient all is close to 1 to the number-average molecular weight of the synthetic boron-contained silicone of different monomers ratio electrochemical process as can be seen from the table, and this may be owing to formed the ring-type low-molecular(weight)polymer.The content of each element can access the boron-contained silicone of a series of different borosilicate ratio contents as can be seen by regulating monomeric ratio from product simultaneously.

Table 1 different monomers proportioning is to molecular weight of product, the influence of each constituent content

Additional proportion by methyl hydrogen dichlorosilane/boron trifluoride diethyl etherate mol ratio 3/1 prepares the infrared spectrogram of boron-contained silicone, referring to Fig. 1.2900-3000cm wherein ^-1The peak corresponds to polysilane CH ₃-upward the stretching vibration of saturated C-H; 2180cm ^-1Absorption peak for Si-H; 1418cm ^-1Be Si-CH ₃The formation vibration of middle C-H; 1260cm ^-1Be Si-CH ₃Middle CH ₃Formation vibration; 1080cm ^-1Be the siloxane bond charateristic avsorption band, this is owing to can not isolate fully due to the oxygen in the experimentation; 460cm ^-1Be silicon silicon key charateristic avsorption band.This shows that boron-contained silicone has Si-CH ₃, Si-H, saturated C-H, building stones such as Si-Si.Meanwhile, boron-contained silicone also has some special absorption peak: 665cm ^-1Be the absorption peak of Si-B key, 1335cm ^-1Be the absorption peak of B-C key, this is the rearrangement because the Si-B key ruptures easily, thereby causes the formation of Si-C-B structure.Thereby illustrate that element boron is incorporated in the polysilane chain really.

Additional proportion by methyl hydrogen dichlorosilane/boron trifluoride diethyl etherate mol ratio 3/1 prepares the ultraviolet spectrogram of boron-contained silicone, referring to Fig. 2.As can be seen from the figure being approximately the 216nm place at wavelength has a narrower absorption peak, this may be because synthetic boron-contained silicone molecular weight ratio lower, formed short Si-Si chain, perhaps on main chain, formed-Si-C-Si or-the Si-C-B structure.At 235nm～270nm place comparatively wide in range assorted peak is arranged all, this has reflected the Si-Si network that three-dimensional branching is arranged in the product, causes the red shift phenomenon.

Prepare boron-contained silicone by the additional proportion of methyl hydrogen dichlorosilane/boron trifluoride diethyl etherate mol ratio 3/1 ¹³The C-NMR collection of illustrative plates is referring to Fig. 3.The peak of 0～1ppm is Si-CH among the figure ₃Resonance peak; 14.26ppm the peak around the 29ppm is BCH ₂The resonance peak of Si; 21.57ppm be-CH ₂-resonance peak; 137.98,129.17,128.36,125.44,20.33ppm is the resonance peak of carbon atom on the solvent toluene.

Embodiment two: prepare the C/C-B-SiC matrix material that to contain the B-SiC matrix with boron-contained silicone as precursor, and use H ₂-O ₂The flame method has contrasted the ablation property of C/C and C/C-B-SiC matrix material.Employing density is 1.19gcm ^-3The C/C matrix material, through three times the dipping density brought up to 1.50gcm ^-3Its density is as shown in table 2 with the variation of dipping number of times.Fig. 4, Fig. 5 have provided the ablation experiments result of flooding C/C-B-SiC matrix material after three times, and the ablation result who has provided C/C simultaneously as a comparison.Density 1.19gcm ^-3The C/C sample through single-steeping, obtain 1.31gcm ^-3C/C-B-SiC, its linear ablative rate, mass ablative rate are lower than density 1.5gcm ^-3C/C.The C/C-B-SiC matrix material is along with the increase of density, and linear ablative rate, mass ablative rate diminish gradually, when the density of material from 1.31gcm ^-3Be increased to 1.50gcm ^-3The time, its 60s linear ablative rate reduces to 0.00433mm/s from 0.0147mm/s, descends 239%; The 60s mass ablative rate reduces to 0.7933mg/s from 1.265mg/s, descends 59.5%.The 90s linear ablative rate reduces to 0.00533mm/s from 0.0136mm/s, descends 154%.Density 1.50gcm ^-3The C/C-B-SiC matrix material, its 60s linear ablative rate is equivalent to density 1.86gcm ^-3The C/C matrix material 61.8%, the 60s mass ablative rate is equivalent to density 1.77gcm ^-3The C/C matrix material; It is 1.86gcm that its 90s linear ablative rate is equivalent to density ^-3The C/C matrix material 61.5%.Boron content in the C/C-B-SiC matrix material: 1.80%; Silicone content: 8.42% (mass ratio), above data declaration is introduced the anti-oxidant ablation property that B-SiC can obviously improve C/C in the matrix.

The density of table 2 C/C-B-SiC matrix material is with the improve of dipping number of times

The dipping number of times	0	1	2	3
					Mean density (gcm -3)	1.19	1.31	1.44	1.50

More than test shows, adopt the electrochemical synthesis method to obtain boron-contained silicone, this kind polysilane can improve the antioxidant property of C/C matrix material significantly, is the ceramic precursor of excellent performance, and this research provides a kind of new approach for the polysilane of anamorphic zone hetero atom.

Claims (1)

1. the synthetic method of a boron-contained silicone is characterized in that this method is is solvent with the tetrahydrofuran (THF), is monomer with two halosilanes or three halosilanes and boron trifluoride, synthesizes boron-contained silicone by electrochemical reaction; The general structure of two halosilanes or three halosilanes is:

Or

Wherein R is C ₁-C ₃Alkyl or phenyl; X represents halogen atom, and concrete steps are as follows:

A. being solvent with the tetrahydrofuran (THF), is that two halosilanes of 3～1:1 or three halosilanes and boron trifluoride ether solution are put into electrochemical reactor with mol ratio, adds the lithium perchlorate supporting electrolyte simultaneously, and the concentration of lithium perchlorate is 0.1mol/L-0.2mol/L;

B. under inert atmosphere, start and stir and ultrasonic wave, energising then begins reaction, and the energising electric energy control is at 1300mAh-1400mAh;

C. after reaction finishes, add toluene, feed ammonia again with dilution and dissolving macromole polysilane, to the reaction system in the remaining Si-Cl key and fully; Pass through press filtration and underpressure distillation then, obtain flaxen liquid boron-contained silicone.

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