CN112142984A - Polyaluminocarbosilane and preparation method and application thereof - Google Patents

Polyaluminocarbosilane and preparation method and application thereof Download PDF

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CN112142984A
CN112142984A CN202011149097.4A CN202011149097A CN112142984A CN 112142984 A CN112142984 A CN 112142984A CN 202011149097 A CN202011149097 A CN 202011149097A CN 112142984 A CN112142984 A CN 112142984A
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silicon
polyaluminocarbosilane
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顾喜双
周永江
郏保琪
曹义
张雄军
尚来东
蒋博
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Zhejiang Huamao Aerospace Technology Co ltd
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Abstract

The invention provides a polyaluminocarbosilane and a preparation method and application thereof, and the method comprises the steps of firstly synthesizing silane containing (Y) d (Z) cSi (Y) d; then silane containing (Y) d (Z) cSi (Y) d and silane are subjected to hydrosilylation reaction to obtain a first intermediate product, and the first intermediate product is reduced to prepare a second intermediate product; carrying out solid-liquid separation treatment on the second intermediate product, and removing solids to prepare polycarbosilane with high silicon-hydrogen bond content; and finally, reacting the polycarbosilane with high silicon-hydrogen bond content with an aluminum-containing compound to obtain the polyaluminum carbosilane. The polyaluminum carbosilane has high content of silicon-hydrogen bonds and high content of aluminum elements, and the content of the silicon-hydrogen bonds and the content of the aluminum elements can be regulated and controlled.

Description

Polyaluminocarbosilane and preparation method and application thereof
Technical Field
The invention belongs to the field of silicon carbide ceramics, and particularly relates to polyaluminocarbosilane and a preparation method and application thereof.
Background
Polyaluminocarbosilane has been noted by researchers at home and abroad as a precursor of the third generation silicon carbide fiber, and has been mass-produced as a precursor of the third generation silicon carbide fiber. The introduction of aluminum can inhibit the crystallization of silicon carbide under high temperature conditions, and is the key to the successful preparation of the aluminum-containing third-generation silicon carbide fiber.
However, the synthesis route of poly-aluminum-carbon-silane is single, and the poly-aluminum-carbon-silane is prepared by the reaction of a silicon-hydrogen bond in a product obtained by pyrolysis of poly-dimethyl-silane and an aluminum-containing compound: the disadvantages of the polydimethyl silane can not be escaped no matter the normal pressure reaction, the high pressure reaction, the polysilane as the reaction raw material or the low molecular weight polycarbosilane as the reaction raw material: the active groups are only one, the content of the silicon-hydrogen bonds is too low, the silicon-hydrogen bond content is 0.7-0.8% measured by a chemical method in polycarbosilane synthesized by polydimethylsiloxane, the theoretical content of the silicon-hydrogen bonds is 1.72%, and the actually measured value is far lower than the theoretical value (Songli, Friekun. SiC precursor-application research development of polycarbosilane [ J ] Chinese material development, 2013, 032(004):243 one 248.). The synthesis of polyaluminocarbosilane (cf. Yuan-Naiyuan, Song Yongcai. Si (Al) C fiber precursor polyaluminocarbosilane [ J ] Proc. national defense science and technology, 2017,039(001): 182-: the reaction consumes silicon hydrogen bonds, the content of the silicon hydrogen bonds in the polycarbosilane is not high, and after aluminum elements are introduced by consuming the silicon hydrogen bonds, the content of the silicon hydrogen bonds in the product is lower, so that the polyaluminocarbosilane has low reaction activity, and a plurality of problems in the application process of the polyaluminocarbosilane occur, such as low reaction activity caused by air unfused, and auxiliary operation is needed, for example, synthesis of the polyaluminocarbosilane as a thermal crosslinking (Yuan, Song Yong Yuan. Si (Al) C fiber precursor [ J ]. national defense science and technology university report, 2017,39(001): 182) 188 ] is adopted in Yuan to solve the problem of the polyaluminocarbosilane in the air unfused process: the PACS fibers were not melted until 240 ℃ and the PCS fibers were melted at 200 ℃. PACS itself contains lower relative Si-H content than PCS, and its reaction rate below 190 deg.C is much lower than PCS. The reaction rate increases gradually when the temperature is >190 ℃ and the temperature at which the gel appears is also higher than for PCS fibers, requiring 200 ℃. The lower active group content and the greater steric hindrance resulting from the high molecular weight make PACS fibers difficult to achieve without melting at lower temperatures. To further increase the degree of crosslinking, the non-melting temperature must therefore be increased, but at the same time more oxygen is introduced.
Further problems are always troubled, the application of polyaluminium carbosilane further reduces the content of silicon hydrogen bonds when an aluminum element compound is fed at a high mass ratio, the reaction activity of the polyaluminium carbosilane is lower, and a large amount of ligand of the aluminum element is found to remain, so that the problems of reduced yield of product ceramic, unstable property, poor spinning performance and the like are caused, and the polyaluminium carbosilane with high aluminum content is difficult to prepare and apply (Yuan, Songyuan-Si (Al) C fiber polyaluminium carbosilane synthesis [ J ] university report of national defense science and technology, 2017,39(001):182- -188.).
In a word, the existing polyaluminum carbosilane has low silicon-hydrogen bond content, and polyaluminum carbosilane with high content of aluminum element and certain silicon-hydrogen reaction activity are difficult to prepare.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a preparation method of polyaluminum carbosilane, which comprises the following steps:
step 1, performing olefin metathesis reaction on silane containing (X) cSi (Y) d under the action of a catalyst to obtain silane containing (Y) d (Z) cSi (Y) d,
wherein X is CH2＝CH-CH2-or CH2CH-, Y is one or more of Cl, Br, I and alkoxy, and Z is-CH-, CH2＝CH-CH2-and-CH2-CH＝CH-CH2-one or more of c and d, the sum of c and d being equal to any one of 2, 3 and 4, c and d being positive integers;
the molecular weight of the silane containing (X) cSi (Y) d is 144-450;
step 2, obtaining a first intermediate product by hydrosilylation reaction of silane containing (Y) d (Z) cSi (Y) d and synthesized in the step 1 and silane;
the hydrosilylation reaction temperature is 20-180 ℃, the reaction time is 10-500 h, and the mass ratio of the silane to the silane containing (Y) d (Z) cSi (Y) d is 1: 0.2-4;
step 3, adding a reducing agent into the fourth intermediate product, reacting for 2-60 hours at-10-60 ℃, and reducing the Y into hydrogen atoms to obtain a second intermediate product;
step 4, carrying out solid-liquid separation treatment on the second intermediate product, and removing solids to prepare polycarbosilane with high silicon-hydrogen bond content;
step 5, mixing the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 and an aluminum-containing compound according to the mass ratio of 1: 0.05-10, and reacting for 0.5-50 h at 60-360 ℃ to obtain the polyaluminum carbosilane.
Further, in the step 1, the olefin double decomposition reaction is a cross double decomposition reaction, and the reaction temperature is 30-220 ℃.
Further, in step 1, the silane containing (X) csi (y) d is selected from any one of the following compounds: vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri-n-propoxysilane, vinyltriisopropoxysilane, vinyltri-n-butoxysilane, vinyltriisobutoxysilane, vinyltri-t-butoxysilane, methylvinyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldi-n-propoxysilane, methylvinylmono-n-propoxysilane, methylvinyldiisopropoxysilane, phenylvinyldiethoxysilane, phenylvinyldimethoxysilane, phenylvinyldi-n-propoxysilane, vinylmonomethoxy-n-propoxysilane, vinyldimethoxymono-n-butoxysilane; vinyltrichlorosilane, vinyltriiodosilane, vinyltribromosilane, vinyldichloromonomethoxysilane, vinyldichloroethoxysilane, vinyldichloron-propoxysilane, vinyldichloroisopropoxysilane, vinyldichloron-butoxysilane, vinyldichloroisobutoxysilane, vinylmonochlorodimethoxysilane, vinylmonochlorodiethoxysilane, methylvinylmonochlorodiethoxysilane, methylvinylmonochloropropoxysilane, methylvinylmonochlorodiethoxysilane, methylvinylmonochloropropoxoxysilane, methylvinylmonochlorodiethoxysilane, vinylmonochlorodiethoxysilane, vinyldichloroethoxysilane, vinylmonochlorodiethoxysilane, vinyl monochlorodin-propoxysilane, vinyl monochlorodiiso-propoxysilane, propenyl trichlorosilane, propenyl tribromosilane, propenyl triiodosilane, propenyl triethoxysilane, propenyl trimethoxysilane, propenyl tripropoxysilane, methacryl diethoxysilane, methacryl dimethoxysilane, methacryl dipropoxysilane, phenylpropyl diethoxysilane, phenylpropenyl dimethoxysilane, phenylpropenyl dipropoxysilane, propenyl monomethoxy-monopropoxysilane; monovinyl-propenyl diethoxysilane, monovinyl-propenyl dimethoxysilane, monovinyl-propenyl dipropoxysilane, divinyldiethoxysilane, divinyldimethoxysilane, divinyldi-n-propoxysilane, divinyldiisopropoxysilane, divinyl di-n-butoxysilane, divinyl dichlorosilane, divinyl diiodosilane, divinyl dibromosilane, divinyl monochloromethoxysilane, divinyl monochloroethoxysilane, divinyl monochloro-n-propoxysilane, divinyl monochloro-isopropoxysilane, divinyl monochloro-n-butoxysilane, divinyl monochloro-isobutoxysilane.
Further, in step 1, the catalyst added in the olefin metathesis reaction is: a highly active metal M-carbene and/or { (CF3)2MeCO } ]2(ArN) -M ═ CH (t-Bu) ], wherein M ═ Mo or W; the dosage of the catalyst is 1-10000 ppm.
Further, in the step 1, a catalyst added in the olefin metathesis reaction is a rhodium-or ruthenium-containing compound, and the amount of the catalyst is 1-10000 ppm.
Further, in step 1, the catalyst is RuCl2(PPh3)3、RuHCI(CO)(PPh3)3、RuCI(SiMe3)(CO)(PPh3)2、[RhCl(cod)]2、Ru＝CHPhCl2(PCy3)2、Ru＝CHPhCl2(PCy3)(SIMes)、[RhCl(cod)]2、[Rh(OSiMe3)(cod)]2And [1, 3-bis (2, 4, 6-trimethylphenyl) -2-imidazolidinylidene]At least one of bis (2-bromopyridine) (phenylmethylene) ruthenium dichloride.
Further, in step 2, the silane is polycarbosilane and/or polysilane.
Furthermore, the polysilane is obtained by pyrolyzing polydimethylsiloxane, has the boiling point of 80-300 ℃, the molecular weight of 118-480 and the content of silicon-hydrogen bonds of about 0.3mol/100g, and is one of the main improved targets of the invention.
Further, the polycarbosilane is obtained by pyrolyzing polydimethylsiloxane, the carbon-silicon ratio is 1.8-1.9: 1, the polycarbosilane comprises liquid polycarbosilane and solid polycarbosilane, the polycarbosilane has serious side carbon, the reduction of the carbon content is to improve the performance of the silicon carbide ceramic and is also a means to improve the precursor, and the silicon carbide precursor is one of the main targets of the improvement of the invention.
Further, the polycarbosilane can be the existing polyaluminocarbosilane with low aluminum content, the silicon hydrogen bond content and activity of the existing polyaluminocarbosilane are lower, and the existing polyaluminocarbosilane is one of the main targets of the improvement of the invention.
In step 3, the reducing agent is at least one of lithium aluminum hydride, lithium hydride, magnesium hydride, sodium hydride and red aluminum, the amount of the reducing agent is preferably such that all Y is reduced to hydrogen atoms and a slight excess is provided, and the amount of the reducing agent is 1 to 66% by mass of the first intermediate product. Preferably, lithium aluminum hydride is used, the preferable using amount is 6-44% of the mass of the first intermediate product, the reduction temperature is preferably-20-60 ℃, and the reduction time is preferably 1-5 h.
Further, in the step 4, the solid-liquid separation treatment is performed for standing for 1-15 hours or centrifugal treatment for 5-45 min or ultrasonic treatment for 10-60 min, and the solid-liquid separation treatment can also be expanded to multiple times of water washing.
Further, in step 5, the aluminum-containing compound is at least one of polyaluminum chloride, diisobutylaluminum hydride, aluminum fluoride, aluminum tripolyphosphate, aluminum sulfide, aluminum tartrate, aluminum tert-butoxide, aluminum dichloride, aluminum glycollate, aluminum trimethyl, dimethylaluminum chloride, aluminum triacetylacetonate, aluminum acetate, diethylaluminum iodide, lithium tri-tert-butoxyaluminum hydride, aluminum tris (4-methyl-8-hydroxyquinoline), aluminum isopropoxide, aluminum acrylate, aluminum triethoxide, and aluminum triphenyl.
Further, when the silicon-hydrogen bond content of the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 is 0.6-0.8 mol/100g, the silicon-hydrogen bond content of the polyaluminum carbosilane prepared in the step 5 can be 0-0.8 mol/100g, the aluminum content of the polyaluminum carbosilane prepared in the step 5 can be 0.02-0.8 mol/100g, and the polyaluminum carbosilane can be subjected to dehydrogenation self-crosslinking reaction.
Further, when the silicon-hydrogen bond content of the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 is 0.8-1.0 mol/100g, the silicon-hydrogen bond content of the polyaluminum carbosilane prepared in the step 5 can be 0-0.98 mol/100g, the aluminum content of the polyaluminum carbosilane prepared in the step 5 can be 0.02-0.98 mol/100g, and the polyaluminum carbosilane can be subjected to dehydrogenation self-crosslinking reaction.
Further, when the silicon-hydrogen bond content of the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 is 1.0-1.68 mol/100g, the silicon-hydrogen bond content of the polyaluminum carbosilane prepared in the step 5 can be 0-1.62 mol/100g, the aluminum content of the polyaluminum carbosilane prepared in the step 5 can be 0.02-1.65 mol/100g, and the polyaluminum carbosilane can be subjected to dehydrogenation self-crosslinking reaction.
Further, when the silicon-hydrogen bond content of the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 is 1.68-1.93 mol/100g, the silicon-hydrogen bond content of the polyaluminum carbosilane prepared in the step 5 can be 0-1.91 mol/100g, the aluminum content of the polyaluminum carbosilane prepared in the step 5 can be 0.01-1.93 mol/100g, and the polyaluminum carbosilane can be subjected to dehydrogenation self-crosslinking reaction.
Further, when the silicon-hydrogen bond content of the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 is 1.93-2.6 mol/100g, the silicon-hydrogen bond content of the polyaluminum carbosilane prepared in the step 5 can be 0-2.51 mol/100g, the aluminum content of the polyaluminum carbosilane prepared in the step 5 can be 0.02-2.58 mol/100g, and the polyaluminum carbosilane can be subjected to dehydrogenation self-crosslinking reaction.
Further, the content of silicon hydrogen bonds in the polyaluminum carbosilane is 0.98-2.51 mol/100g, the polyaluminum carbosilane can perform dehydrogenation self-crosslinking reaction, and the polyaluminum carbosilane contains Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aAnd a is one of the values 1, 2 and 3.
The invention also provides polyaluminocarbosilane which is prepared by the various methods and consists of SiC1.47～ 1.8H489～6.45O0.06～4.8Al0.02～1.28。
Further, the content of a silicon-hydrogen bond in the polyaluminium carbosilane is 0-2.51 mol/100g, the polyaluminium carbosilane can perform a dehydrogenation self-crosslinking reaction, and the polyaluminium carbosilane contains Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aAnd a is any one of the numerical values of 1, 2 and 3.
Further, the silicon to carbon ratio of the polyaluminocarbosilane can be adjusted on the basis of the polycarbosilane or polysilane.
Further, the silicon-carbon ratio in the polyaluminum carbosilane is 1:1.47, and the polyaluminum carbosilane can contain Si (H)3-C-C-Si(H)3、Si(H)2-C-C-Si(H)3、Si(H)2-C-C-Si(H)2、Si(H)1-C-C-Si(H)3、Si(H)1-C-C-Si(H)2、Si(H)2-C-C-Si(H)3One or more of the groups, the presence of which, ensure the activity of the polyaluminocarbosilane, for example, dehydroaddition. Of course, it is also possible to react all of the silicon-hydrogen bonds in the above groups to increase the aluminum content, with the aluminum being pendant and/or bridging.
Further, the silicon carbon of the polyaluminum carbosilane is 1: 1.47-1.86, and Si (H) is addeda-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aIntroduction and Regulation of groups Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aThe composition of the radicals can be controlled by the silicon-carbon ratio, for example, Si (Cl) can be selected3-C＝C-Si(Cl)3Or Si (Cl)3-C-C＝C-Si(Cl)3The former has a more significant effect of reducing the carbon-silicon ratio (in the present invention, the carbon-silicon ratio or the silicon-carbon ratio is an atomic number ratio relative to the raw material silane).
Further, the silicon-carbon ratio of the polyaluminum carbosilane is 1: 1.86-1.92, and the polyaluminum carbosilane is prepared by using Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aIntroduction and Regulation of groups Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aThe composition of the radicals can be controlled by the silicon-carbon ratio, for example, Si (Cl) can be selected3-C-C-＝C-C-Si(Cl)3、Si(Cl)2-C＝C-Si(Cl)2And Si (Cl)1-C-C-＝C-C-Si(Cl)1Wherein, Si (Cl)1-C-C-＝C-C-Si(Cl)1The effect of increasing the carbon-silicon ratio is more obvious (in the invention, the silicon-carbon ratio is an atomic number ratio).
The polyaluminum carbosilanes can be divided into two types according to the dehydrogenation and crosslinking: the high-silicon-hydrogen-content and high-silicon-hydrogen-activity poly-aluminum carbosilane can be dehydrogenated and crosslinked and can not be dehydrogenated and crosslinked, the silicon-hydrogen-content and low-silicon-hydrogen-activity in the poly-aluminum carbosilane structure are high and can be 0.98-2.58 mol/100g, the softening point is higher than 30 ℃ and even higher than 400 ℃; among the dehydrogenatively crosslinkable polyaluminocarbosilanes, there are again three categories: the softening point is above the dehydrogenation crosslinking curing temperature, the softening point is overlapped or partially overlapped with the dehydrogenation crosslinking curing temperature, the softening points of the two softening points are below the dehydrogenation crosslinking curing temperature, the softening points of the two softening points can be inferred only through the softening points of the raw materials and cannot be obtained through measurement, and the softening point of a third party can be between 20 ℃ and 180 ℃, and can be adjusted.
The invention also provides an application of the polyaluminocarbosilane prepared by the method in preparing silicon carbide fibers, which comprises the following specific steps: and carrying out melt spinning or dry spinning treatment on the polyaluminocarbosilane to obtain polyaluminocarbosilane fibers, and sequentially carrying out non-melting treatment and heat treatment on the polyaluminocarbosilane fibers to obtain the silicon carbide fibers.
Further, the polyaluminum carbosilane is subjected to melt spinning or dry spinning to obtain polyaluminum carbosilane fibers with the diameter of 1-8 microns, the obtained polyaluminum carbosilane fibers are subjected to non-melting, preferably electron beam irradiation, preferably irradiation temperature of-50-30 ℃, and measured at 0.1-2 MGy, preferably measured at 0.5-1 MGy, the gel content of the obtained non-melting fibers is higher than 80%, preferably under inert atmosphere protection, the oxygen content of the non-melting fibers is lower than 0.8% during inert atmosphere protection, the fibers can be directly subjected to irradiation in the air, the oxygen content of the non-melting fibers is 1.6-4.6%, the irradiation dosage is far lower than that in the prior art (5-25 MGy), and the traditional problems that the fibers are easy to melt and combine in the prior irradiation process are solved due to the great reduction of irradiation dosage.
Carrying out heat treatment on the non-melting fibers, preferably the non-melting fibers with the oxygen content of less than 0.8%, in hydrogen to 1800 ℃ to obtain silicon carbide fibers, wherein the silicon-carbon ratio is 1.01-1.4, and the oxygen content is less than 1%; the more preferable result is that: the silicon-carbon ratio is 1.01-1.04, the oxygen content is lower than 0.8%, the diameter is 0.75-8 um, the tensile strength is 2.0-4.5 Gpa, and the density is 2.8-3.01 g/cm3Young modulus is 360-400 GPa; the more preferable result is that: the tensile strength is 2.8-4.5 Gpa, and the density is 2.9-3.01 g/cm3And the Young modulus is 380-400 GPa.
Further, the method can be used for preparing a novel materialSecondly, performing heat treatment on the non-melting fibers, preferably the non-melting fibers with the oxygen content of 1.6-4.6%, in high-purity argon to 1800 ℃ to obtain silicon carbide fibers, wherein the silicon-carbon ratio is 1.01-1.3, and the oxygen content is lower than 0.9%; the more preferable result is that: the silicon-carbon ratio is 1.01-1.1, the oxygen content is lower than 0.8%, the diameter is 0.75-8 um, the tensile strength is 2.0-4.6 Gpa, and the density is 2.7-2.98 g/cm3Young modulus is 330-380 GPa; the more preferable result is that: the tensile strength is 2.6-4.6 Gpa, and the density is 2.9-2.98 g/cm3And the Young modulus is 360-380 GPa.
The invention has the following beneficial effects:
1. the invention provides a preparation method of polyaluminum carbosilane, which comprises the steps of firstly carrying out olefin metathesis reaction on silane containing (X) cSi (Y) d (Z) cSi (Y) d as a raw material to obtain silane containing (Y) d (Z) cSi (Y) d, and then carrying out hydrosilylation reaction on the silane containing (Y) d (Z) cSi (Y) d and silane to obtain a first intermediate product; then reducing the first intermediate product to prepare a second intermediate product; carrying out solid-liquid separation treatment on the second intermediate product, and removing solids to obtain polycarbosilane with high silicon-hydrogen bond content; and finally, reacting the polycarbosilane with high silicon-hydrogen bond content with an aluminum-containing compound to prepare the polyaluminum carbosilane. The polyaluminum carbosilane prepared by the method has high and adjustable aluminum content, and the polyaluminum carbosilane has high and adjustable silicon-hydrogen bond content. The content of silicon-hydrogen bonds and the content of aluminum in the polyaluminum carbosilane prepared by the method can be simultaneously far higher than the content of silicon-hydrogen bonds and the content of aluminum in the polyaluminum carbosilane prepared by the prior art, and the polyaluminum carbosilane aluminum can be used as a raw material for preparing silicon carbide ceramics with high aluminum-containing elements.
2. The method can regulate and control the silicon-hydrogen bond content of the polyaluminum carbon silane within the range of 0-2.51 mol/100g, and can obtain the polyaluminum carbon silane with different silicon-hydrogen bond contents. The method can regulate and control the aluminum content of the polyaluminum carbosilane within the range of 0.02-2.58 mol/100g, and can obtain the polyaluminum carbosilane with different aluminum contents.
3. The method can regulate and control the silicon-carbon ratio of the polyaluminum carbon silane within the range of 1: 1.47-1.92, and can obtain the polyaluminum carbon silane with different silicon-carbon ratios.
4. The polyaluminum carbosilane prepared by the method can contain two active groups, namely a silicon-hydrogen bond and a C ═ C bond, can be subjected to dehydrogenation addition and hydrosilylation to form new polyaluminum carbosilane, and the softening point and the self-crosslinking temperature of the product can be regulated and controlled by controlling the addition degree.
Drawings
FIG. 1 is a scanning electron micrograph of a silicon carbide fiber obtained in example thirteen.
Detailed Description
It is worth mentioning that: the terms "first", "second", and the like in the present invention are used for clearly describing the technical solutions, and are not limitations of the technical solutions. The operations of step 1, step 2 and the like in the invention are all carried out under the protection of inert gas.
The invention will be further illustrated with reference to specific examples:
[ EXAMPLES one ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C-C＝C-C-Si(Cl)3，
The propenyl trichlorosilane was charged to the autoclave and 100ppm RuCI (SiMe) was added3)(CO)(PPh3)2Performing cross double decomposition reaction at 160 deg.C under 20Mpa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C-C＝C-C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
si (Cl) synthesized by step 13-C-C＝C-C-Si(Cl)3With 100g of liquid polycarbosilane (silicon hydrogen bond content 0.7mol/100g, liquid state, molecular weight 300, molecular weight distribution coefficient 1.1, composition of SiC1.86H7.50O0.02) Carrying out hydrosilylation reaction, liquid polycarbosilane and Si (Cl)3-C-C＝C-C-Si(Cl)3The mass ratio is 1: 0.33; the hydrosilylation reaction temperature is 20 ℃, and the reaction time is 200h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
6.27g of lithium aluminum hydride was added to the first intermediate product, and reacted at 20 ℃ for 30 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
Step 4, standing the second intermediate product for 1h for solid-liquid separation treatment, and removing 36.97g of solids to obtain polycarbosilane with high silicon-hydrogen bond content; the polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 1.08mol/100g, the molecular weight of 356 in a liquid state and the molecular weight distribution coefficient of 1.1, and the polycarbosilane with high silicon-hydrogen bond content is composed of SiC1.87H7.34O0.02。
And 5, reacting the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 with aluminum acetate to prepare the polyaluminum carbosilane, wherein the reaction temperature is 360 ℃, the reaction time is 50 hours, and the mass ratio of the polycarbosilane with high silicon-hydrogen bond content to the aluminum acetate is 1: 0.74.
the content of silicon-hydrogen bonds of the polyaluminum carbosilane is 0mol/100g, the content of aluminum is 0.36mol/100g, and SiC is formed1.87H6.45O0.8Al0.18。
[ example two ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C-C＝C-C-Si(Cl)3，
The propenyl trichlorosilane was charged to the autoclave and 10ppm RuCI (SiMe) was added3)(CO)(PPh3)2Performing cross double decomposition reaction at 80 deg.C under 5Mpa for 600 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C-C＝C-C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C-C＝C-C-Si(Cl)3The silicon-carbon bond content of the SiC powder is 0.7mol/100g, the liquid SiC powder has the molecular weight of 300 and the molecular weight distribution coefficient of 1.1 and is mixed with liquid polycarbosilane (the silicon-hydrogen bond content is 0.7mol/100g, the liquid SiC powder is liquid1.86H7.50O0.02) Carrying out hydrosilylation reaction, liquid polymerizationCarbosilane with Si (Cl)3-C-C＝C-C-Si(Cl)3The mass ratio is 1: 0.97; the hydrosilylation reaction temperature is 40 ℃, and the reaction time is 500 hours, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
18.81g of lithium aluminum hydride was added to the first intermediate product, and reacted at 0 ℃ for 60 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
Step 4, standing the second intermediate product for 3 hours, and removing 80.91g of solids to obtain the polycarbosilane with high silicon-hydrogen bond content, wherein the polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 1.63mol/100g, the polycarbosilane with high silicon-hydrogen bond content is in a liquid state, the molecular weight is 386, the molecular weight distribution coefficient is 1.1, and the polycarbosilane with high silicon-hydrogen bond content contains Si (H)3-C-C-C-C-Si(H)3And (5) structure. The polycarbosilane with high silicon-hydrogen bond content is composed of SiC1.89H7.11O0.01Compared with the liquid polycarbosilane as the raw material, the carbon-silicon ratio is increased, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 with aluminum acetate at the reaction temperature of 300 ℃ for 40h, wherein the mass ratio of the polycarbosilane with high silicon-hydrogen bond content to the aluminum acetate is 1: 0.88.
the content of silicon-hydrogen bonds and the content of aluminum in the prepared polyaluminum carbosilane are respectively 0.32mol/100g and 0.43mol/100g, and the composition is SiC1.89H6.31O0.9Al0.23。
[ EXAMPLE III ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C-C＝C-C-Si(Cl)3，
The propenyl trichlorosilane was charged to the autoclave and 600ppm RuCI (SiMe) was added3)(CO)(PPh3)2Performing cross double decomposition reaction at 160 deg.C under 5Mpa for 500 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C-C＝C-C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C-C＝C-C-Si(Cl)3The silicon-carbon bond content of the SiC powder is 0.7mol/100g, the liquid SiC powder has the molecular weight of 300 and the molecular weight distribution coefficient of 1.1 and is mixed with liquid polycarbosilane (the silicon-hydrogen bond content is 0.7mol/100g, the liquid SiC powder is liquid1.86H7.50O0.02) Carrying out hydrosilylation reaction, liquid polycarbosilane and Si (Cl)3-C-C＝C-C-Si(Cl)3The mass ratio is 1: 1.62; the hydrosilylation reaction temperature is 60 ℃, and the reaction time is 100 hours, so that the first intermediate product is prepared.
And 3, reducing the first intermediate product to obtain a second intermediate product.
Adding 31.35g of lithium aluminum hydride to the first intermediate product, reacting at 30 ℃ for 40 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product,
and 4, standing the second intermediate product for 10 hours, and removing 161.5g of solid to obtain the polycarbosilane.
The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.02mol/100g, is liquid, has the molecular weight of 408 and the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-C-C-Si(H)3Structure of composition of SiC1.90H6.95O0.01. Compared with the liquid polycarbosilane as the raw material, the carbon-silicon ratio is increased, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 with an aluminum acetate substance at the reaction temperature of 200 ℃ for 0.5h, wherein the mass ratio of the polycarbosilane with high silicon-hydrogen bond content to the aluminum acetate is 1: 0.82.
the content of silicon-hydrogen bonds in the prepared polyaluminum carbosilane is 0.81mol/100g, the content of aluminum is 0.404mol/100g, and the composition is SiC1.90H6.25O0.89Al0.21。
[ EXAMPLE IV ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C-C＝C-C-Si(Cl)3，
Adding propenyl trichlorosilane intoInto the autoclave, 1000ppm of RuCI (SiMe) was added3)(CO)(PPh3)2Performing cross double decomposition reaction at 260 deg.C under 25Mpa for 50 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C-C＝C-C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C-C＝C-C-Si(Cl)3The silicon-carbon bond content of the SiC powder is 0.7mol/100g, the liquid SiC powder has the molecular weight of 300 and the molecular weight distribution coefficient of 1.1 and is mixed with liquid polycarbosilane (the silicon-hydrogen bond content is 0.7mol/100g, the liquid SiC powder is liquid1.86H7.50O0.02) Carrying out hydrosilylation reaction, liquid polycarbosilane and Si (Cl)3-C-C＝C-C-Si(Cl)3The mass ratio is 1: 2.26; the hydrosilylation reaction temperature is 100 ℃, and the reaction time is 300h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
43.89g of lithium aluminum hydride was added to the first intermediate product, and reacted at 60 ℃ for 80 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 15 hours, and removing 188.79g of solid to prepare the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.32mol/100g, is liquid, has the molecular weight of 437, has the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-C-C-Si(H)3Structure of composition of SiC1.92H6.83O0.01Compared with the liquid polycarbosilane as the raw material, the carbon-silicon ratio is increased, and the content of silicon-hydrogen bonds is obviously increased.
Step 5, reacting the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 with aluminum acetate to prepare polyaluminum carbosilane, wherein the reaction temperature is 200 ℃, the reaction time is 0.5h to prepare the polyaluminum carbosilane, and the mass ratio of the polycarbosilane with high silicon-hydrogen bond content to the aluminum acetate is 1: 0.79.
the content of silicon-hydrogen bonds in the prepared polyaluminum carbosilane is 1.17mol/100g, the content of aluminum is 0.39mol/100g, and the composition is SiC1.87H6.28O0.69Al0.20。
[ EXAMPLE V ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged to an autoclave and 200ppm RuCI (SiMe) was added3)(CO)(PPh3)2Performing cross double decomposition reaction at 130 deg.C under 25Mpa for 400 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Synthesis of polyaluminum carbosilane with polyaluminum carbosilane (reference: Yuan, Song Yongcai. Si (Al)) C fiber precursor [ J]The university of defense science and technology, 2017,039(001): 182-; silicon-hydrogen bond content of 0.45mol/100g, solid state, molecular weight of 1500, molecular weight distribution coefficient of 2.9, SiC1.88H6.40O0.07Al0.01) Carrying out hydrosilylation, wherein the system of the hydrosilylation also comprises a solvent xylene, the mass ratio of the xylene to the polyaluminum carbosilane is 1, and the polyaluminum carbosilane and Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 0.30; the hydrosilylation reaction temperature is 150 ℃, and the reaction time is 10 hours, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
6.27g of lithium aluminum hydride was added to the first intermediate product, and reacted at-5 ℃ for 100 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 3 hours, and removing 27.00g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content.
The polycarbosilane with high silicon-hydrogen bond content contains 0.87mol/100g of silicon-hydrogen bond, 1589 of molecular weight and 2.9 of molecular weight distribution coefficient, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.79H6.16O0.06Al0.01Compared with the raw material polyaluminium carbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 0.09 at the reaction temperature of 60 ℃ for 30h to prepare the polyaluminum carbosilane.
The prepared polyaluminum carbosilane has the silicon-hydrogen bond content of 0.81mol/100g and the aluminum content of 0.02mol/100g, and is SiC in composition1.79H6.11O0.06Al0.02。
[ EXAMPLE six ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 300ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 90 deg.C under 20Mpa for 600 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation with polyaluminocarbosilane (see example five), wherein the hydrosilylation reaction system also comprises solvent xylene, the mass of the xylene/polyaluminocarbosilane is 2, and the polyaluminocarbosilane is reacted with Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 0.59; the hydrosilylation reaction temperature is 120 ℃, and the reaction time is 200 hours, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
12.54g of lithium aluminum hydride was added to the first intermediate product, and reacted at 18 ℃ for 30 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
Step 4, standing the second intermediate product for 8 hours, and removing 53.94g of solid to prepare the high silicon-hydrogen bond content polycarbonXylene solution of silane. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 1.23mol/100g, the molecular weight of 1614 and the molecular weight distribution coefficient of 2.9, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.71H5.95O0.06Al0.01Compared with the raw material polyaluminium carbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high-silicon-hydrogen-bond-content polycarbosilane prepared in the step 4 with aluminum acetate to prepare polyaluminum carbosilane, wherein the mass ratio of the high-silicon-hydrogen-bond-content polycarbosilane to the aluminum acetate is 1: 0.25, the reaction temperature is 360 ℃, and the reaction time is 50 h.
The content of silicon-hydrogen bonds in the prepared polyaluminium carbosilane is 0.86mol/100g, the content of aluminum is 0.06mol/100g, and the composition is SiC1.71H5.53O0.25Al0.07。
[ EXAMPLE VII ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 600ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 200 deg.C under 10Mpa for 100 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation reaction with polyaluminium carbosilane (see example five), wherein the hydrosilylation reaction system also comprises solvent xylene, the mass of the xylene/polyaluminium carbosilane is 4,
polyaluminocarbosilane with Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 1.18; the hydrosilylation reaction temperature is 180 ℃, and the reaction time is 100 hours, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
adding 25.08g of lithium aluminum hydride to the first intermediate product, reacting at 28 ℃ for 60 hours, and reducing the Y into a hydrogen atom, thereby preparing the second intermediate product.
And 4, standing the second intermediate product for 6 hours, and removing 1.7.9g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content contains 1.81mol/100g of silicon-hydrogen bond content, 1656 of molecular weight and 2.9 of molecular weight distribution coefficient, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.60H5.64O0.05Al0.01Compared with the raw material polyaluminium carbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high-silicon-hydrogen-bond-content polycarbosilane prepared in the step 4 with aluminum acetate to prepare polyaluminum carbosilane, wherein the mass ratio of the high-silicon-hydrogen-bond-content polycarbosilane to the aluminum acetate is 1: 0.1, the reaction temperature is 200 ℃, and the time is 10 hours.
The prepared polyaluminum carbosilane has the silicon-hydrogen bond content of 0.54mol/100g and the aluminum content of 0.42mol/100g, and is SiC in composition1.60H5.01O0.69Al0.21。
[ example eight ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 500ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 160 deg.C under 10MPa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation reaction with polyaluminocarbosilane (see example five), wherein the hydrosilylation reaction system also comprises solvent xylene, the mass ratio of the xylene to the polyaluminocarbosilane is 4, and the polyaluminocarbosilane and Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 1.33; hydrosilylationThe reaction temperature was 135 ℃ and the reaction time was 500h, thereby obtaining the first intermediate product.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
28.3g of lithium aluminum hydride was added to the first intermediate product, and the reaction was carried out at 69 ℃ for 200 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 15 hours, and removing 121.4g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. And (3) distilling the dimethylbenzene at 60 ℃ under reduced pressure, wherein the polycarbosilane with high silicon-hydrogen bond content is in a solid state.
The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 1.93mol/100g molecular weight 1729 and the molecular weight distribution coefficient of 2.9, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.58H5.58O0.05Al0.01Compared with the raw material polyaluminium carbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 0.78, the reaction temperature is 80 ℃, and the polyaluminum carbosilane is prepared after 10 hours.
The prepared polyaluminum carbosilane has the silicon-hydrogen bond content of 0.72mol/100g and the aluminum content of 0.38mol/100g, and is SiC in composition1.58H4.89O1.01Al0.22。
[ EXAMPLE ninth ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 500ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 160 deg.C under 10MPa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation reaction with polycarbosilane (see example one), wherein the hydrosilylation reaction system also comprises solvent xylene, the mass of the xylene/polycarbosilane is 1,
polyaluminocarbosilane with Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 2.07; the hydrosilylation reaction temperature is 110 ℃, and the reaction time is 600h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
43.9g of lithium aluminum hydride was added to the first intermediate product, and reacted at 69 ℃ for 200 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 100 hours, and removing 188.8g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.6mol/100g, the molecular weight of 403 and the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.47H5.93O0.01Compared with the raw material polycarbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 0.78 at 100 deg.c for 0.5 hr to obtain polyaluminium carbosilane.
The content of silicon-hydrogen bonds in the prepared polyaluminum carbosilane is 1.31mol/100g, the content of aluminum is 0.43mol/100g, and the composition is SiC1.47H5.34O0.83Al0.21。
[ EXAMPLE eleven ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 500ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 160 deg.C under 10MPa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation with polycarbosilane (see example one), wherein the hydrosilylation system also comprises solvent xylene, the mass of the xylene and the polycarbosilane is 1, and polyaluminocarbosilane and Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 2.07; the hydrosilylation reaction temperature is 110 ℃, and the reaction time is 600h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
43.9g of lithium aluminum hydride was added to the first intermediate product, and reacted at 69 ℃ for 200 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 100 hours, and removing 188.8g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.6mol/100g, the molecular weight of 403 and the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.47H5.93O0.01Compared with the raw material polycarbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 10, the reaction temperature is 300 ℃, and unreacted aluminum acetate is distilled after 50 hours to prepare the polyaluminum carbosilane.
The prepared polyaluminum carbosilane has the silicon-hydrogen bond content of 0mol/100g and the aluminum content of 0.86mol/100g, and is SiC in composition1.47H4.89O2.13Al0.41。
[ example eleven ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 500ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 160 deg.C under 10MPa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation with polycarbosilane (see example one), wherein the hydrosilylation system also comprises solvent xylene, the mass ratio of the xylene to the polycarbosilane is 1, and the polyaluminocarbosilane and Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 2.07; the hydrosilylation reaction temperature is 110 ℃, and the reaction time is 600h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
43.9g of lithium aluminum hydride was added to the first intermediate product, and reacted at 69 ℃ for 200 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 100 hours, and removing 188.8g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.6mol/100g, the molecular weight of 403 and the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.47H5.93O0.01Compared with the raw material polycarbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 10 at the reaction temperature of 60 ℃ for 50h, and distilling unreacted aluminum acetate to obtain the polyaluminum carbosilane.
The silicon-hydrogen bond content of the polyaluminum carbosilane is 0mol/100g, and the aluminum content is 258mol/100g of SiC in composition1.47H3.61O4.8Al1.28。
[ EXAMPLE twelfth ]
A preparation method of polycarbosilane comprises the following steps:
step 1, Synthesis of Si (Cl)3-C＝C-Si(Cl)3，
The vinyltrichlorosilane was charged into an autoclave, and 500ppm of [ RhCl (cod) ]was added]2Performing cross double decomposition reaction at 160 deg.C under 10MPa for 300 hr, cooling to room temperature, and distilling under reduced pressure to obtain Si (Cl)3-C＝C-Si(Cl)3。
Step 2, synthesizing a first intermediate product,
with Si (Cl)3-C＝C-Si(Cl)3Carrying out hydrosilylation with polycarbosilane (see example one), wherein the hydrosilylation system also comprises solvent xylene, the mass ratio of the xylene to the polycarbosilane is 1, and the polyaluminocarbosilane and Si (Cl)3-C＝C-Si(Cl)3The mass ratio is 1: 2.07; the hydrosilylation reaction temperature is 110 ℃, and the reaction time is 600h, so that the first intermediate product is prepared.
Step 3, reducing the first intermediate product to prepare a second intermediate product,
43.9g of lithium aluminum hydride was added to the first intermediate product, and reacted at 69 ℃ for 200 hours to reduce the Y to a hydrogen atom, thereby producing the second intermediate product.
And 4, standing the second intermediate product for 100 hours, and removing 188.8g of solid to prepare the xylene solution of the polycarbosilane with high silicon-hydrogen bond content. The polycarbosilane with high silicon-hydrogen bond content has the silicon-hydrogen bond content of 2.6mol/100g, the molecular weight of 403 and the molecular weight distribution coefficient of 1.1, and contains Si (H)3-C-C-Si(H)3Structure of composition of SiC1.47H5.93O0.01Compared with the raw material polycarbosilane, the carbon-silicon ratio is reduced, and the content of silicon-hydrogen bonds is obviously increased.
And 5, reacting the high silicon-hydrogen bond content polycarbosilane prepared in the step 4 with aluminum acetate, wherein the mass ratio of the high silicon-hydrogen bond content polycarbosilane to the aluminum acetate is 1: 0.05, the reaction temperature is 100 ℃, and the polyaluminum carbosilane is prepared after 0.5 h.
The content of silicon-hydrogen bonds of the polyaluminum carbosilane is 2.51mol/100g, the content of aluminum is 0.043mol/100g, and the composition is SiC1.47H4.92O0.06Al0.02。
[ EXAMPLE thirteen ]
Mutually dissolving the polyaluminum carbosilane of the ninth embodiment with cyclohexane in a ratio of 1:0.58, carrying out solution spinning at a spinning temperature of 40 ℃, a spinning pressure of 0.1MPa and a drying air temperature of 55 ℃ to obtain polyaluminum carbosilane fibers with the diameter of 8um, carrying out electron beam irradiation on the polyaluminum carbosilane fibers in air, measuring 1MGy and the gel content of 80%, pyrolyzing the fibers at 1800 ℃ in high-purity argon to obtain silicon carbide fibers with the diameter of 6.6um, and carrying out carbon: silicon atom ratio of 1.2, oxygen content, 0.9%, tensile strength of 3.8GPa, density of 2.7g/cm3Young's modulus 360 GPa.
Fig. 1 is a scanning electron micrograph of the silicon carbide fiber prepared in this example, which is used to observe the microstructure of the fiber. As can be seen from FIG. 1, the prepared silicon carbide fiber has smooth surface, no obvious large crystal particles and gaps, and excellent compactness.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A preparation method of polyaluminum carbosilane is characterized by comprising the following steps: the method comprises the following steps:
step 1, performing olefin metathesis reaction on silane containing (X) cSi (Y) d under the action of a catalyst to obtain silane containing (Y) d (Z) cSi (Y) d;
wherein X is CH2＝CH-CH2-or CH2CH-, Y is one or more of Cl, Br, I and alkoxy, and Z is-CH-, CH2＝CH-CH2-and-CH2-CH＝CH-CH2-one or more of c and d, the sum of c and d being equal to any one of 2, 3 and 4, c and d being positive integers;
step 2, reacting silane containing (Y) d (Z) cSi (Y) d synthesized in the step 1 with silane according to the mass ratio of 0.2-4: 1 at 20-180 ℃ for 10-500 h to obtain a first intermediate product;
step 3, adding a reducing agent into the first intermediate product, reacting for 2-60 hours at-10-60 ℃, and reducing the Y into a hydrogen atom to obtain a second intermediate product;
step 4, carrying out solid-liquid separation treatment on the second intermediate product, and removing solids to obtain polycarbosilane with high silicon-hydrogen bond content;
step 5, mixing the polycarbosilane with high silicon-hydrogen bond content prepared in the step 4 with an aluminum-containing compound according to a mass ratio of 1: 0.05-10, and reacting for 0.5-50 h at 60-360 ℃ to obtain the polyaluminum carbosilane.
2. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in the step 1, the olefin double decomposition reaction is a cross double decomposition reaction, and the reaction temperature is 30-220 ℃.
3. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in step 1, the catalyst added in the olefin metathesis reaction is a high activity metal M-carbene and/or { (CF3)2MeCO } ]2(ArN) -M ═ CH (t-Bu) ], wherein M ═ Mo or W; the dosage of the catalyst is 1-10000 ppm.
4. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in the step 1, a catalyst added in the olefin metathesis reaction is a rhodium-or ruthenium-containing compound, and the dosage of the catalyst is 1-10000 ppm.
5. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in the step 2, the silane is polycarbosilane and/or polysilane.
6. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in the step 3, the reducing agent is at least one of lithium aluminum hydride, lithium hydride, magnesium hydride, sodium hydride and red aluminum, and the amount of the reducing agent is 1-66% of the mass of the first intermediate product.
7. The method for preparing polyaluminocarbosilane as claimed in claim 1, wherein: in step 5, the aluminum-containing compound is at least one of polyaluminum chloride, diisobutylaluminum hydride, aluminum fluoride, aluminum tripolyphosphate, aluminum sulfide, aluminum tartrate, aluminum tert-butoxide, aluminum dichloride, aluminum glycollate, aluminum trimethyl, dimethylaluminum chloride, aluminum triacetylacetonate, aluminum acetate, aluminum diethyliodide, lithium tri-tert-butoxyaluminum hydride, tris (4-methyl-8-hydroxyquinoline) aluminum, aluminum isopropoxide, aluminum acrylate, aluminum triethoxide, and aluminum triphenyl.
8. A polyaluminocarbosilane prepared by the process according to any one of claims 1 to 7 wherein: the composition of the polyaluminum carbosilane is SiC1.47～1.8H489～6.45O0.06～4.8Al0.02～1.28。
9. The polyaluminocarbosilane of claim 8, wherein: the content of a silicon-hydrogen bond in the polyaluminocarbosilane is 0-2.51 mol/100g, the polyaluminocarbosilane can perform a dehydrogenation self-crosslinking reaction, and the polyaluminocarbosilane contains Si (H)a-C-C-Si(H)aRadicals or Si (H)a-C-C-C-Si(H)aAnd a is any one of the numerical values of 1, 2 and 3.
10. Use of a polyaluminocarbosilane prepared by the process of any one of claims 1 to 7 in the preparation of silicon carbide fibres characterised in that: and carrying out melt spinning or dry spinning treatment on the polyaluminocarbosilane to obtain polyaluminocarbosilane fibers, and sequentially carrying out non-melting treatment and heat treatment on the polyaluminocarbosilane fibers to obtain the silicon carbide fibers.
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