CN116284801B - Synthesis method of polycarbosilane - Google Patents
Synthesis method of polycarbosilane Download PDFInfo
- Publication number
- CN116284801B CN116284801B CN202310112896.1A CN202310112896A CN116284801B CN 116284801 B CN116284801 B CN 116284801B CN 202310112896 A CN202310112896 A CN 202310112896A CN 116284801 B CN116284801 B CN 116284801B
- Authority
- CN
- China
- Prior art keywords
- temperature
- pressure
- polysilane
- synthesis device
- polycarbosilane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229920003257 polycarbosilane Polymers 0.000 title claims abstract description 50
- 238000001308 synthesis method Methods 0.000 title claims abstract description 9
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 59
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 57
- 229920000548 poly(silane) polymer Polymers 0.000 claims abstract description 40
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- 238000001704 evaporation Methods 0.000 claims abstract description 35
- 238000010438 heat treatment Methods 0.000 claims abstract description 33
- 230000008020 evaporation Effects 0.000 claims abstract description 28
- 239000007788 liquid Substances 0.000 claims abstract description 14
- 238000013461 design Methods 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 31
- 230000008569 process Effects 0.000 claims description 17
- 150000003384 small molecules Chemical class 0.000 claims description 14
- 239000007787 solid Substances 0.000 claims description 13
- 230000002194 synthesizing effect Effects 0.000 claims description 13
- 238000004321 preservation Methods 0.000 claims description 10
- 239000000843 powder Substances 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 238000009413 insulation Methods 0.000 claims description 6
- 239000010935 stainless steel Substances 0.000 claims description 5
- 229910001220 stainless steel Inorganic materials 0.000 claims description 5
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 4
- 239000010962 carbon steel Substances 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000012267 brine Substances 0.000 claims description 3
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims description 3
- 239000008399 tap water Substances 0.000 claims description 3
- 235000020679 tap water Nutrition 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 2
- 238000003776 cleavage reaction Methods 0.000 claims 1
- 238000007872 degassing Methods 0.000 claims 1
- 230000007017 scission Effects 0.000 claims 1
- 238000006068 polycondensation reaction Methods 0.000 abstract description 15
- 238000009833 condensation Methods 0.000 abstract description 11
- 230000005494 condensation Effects 0.000 abstract description 11
- 239000002994 raw material Substances 0.000 abstract description 8
- 238000009835 boiling Methods 0.000 abstract description 4
- 238000010992 reflux Methods 0.000 abstract description 4
- 239000000376 reactant Substances 0.000 abstract description 3
- 238000002309 gasification Methods 0.000 abstract description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 20
- 239000000047 product Substances 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 11
- 230000008707 rearrangement Effects 0.000 description 10
- 238000000197 pyrolysis Methods 0.000 description 8
- 238000005336 cracking Methods 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 229910010271 silicon carbide Inorganic materials 0.000 description 6
- 239000012265 solid product Substances 0.000 description 6
- 239000000706 filtrate Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000004821 distillation Methods 0.000 description 4
- 239000012263 liquid product Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 150000001367 organochlorosilanes Chemical class 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 229910010082 LiAlH Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- CZDYPVPMEAXLPK-UHFFFAOYSA-N tetramethylsilane Chemical compound C[Si](C)(C)C CZDYPVPMEAXLPK-UHFFFAOYSA-N 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910000799 K alloy Inorganic materials 0.000 description 1
- 229910000528 Na alloy Inorganic materials 0.000 description 1
- 229910001257 Nb alloy Inorganic materials 0.000 description 1
- 229910018540 Si C Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000011153 ceramic matrix composite Substances 0.000 description 1
- 239000012700 ceramic precursor Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- INFDPOAKFNIJBF-UHFFFAOYSA-N paraquat Chemical compound C1=C[N+](C)=CC=C1C1=CC=[N+](C)C=C1 INFDPOAKFNIJBF-UHFFFAOYSA-N 0.000 description 1
- 229920000673 poly(carbodihydridosilane) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000004227 thermal cracking Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/60—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which all the silicon atoms are connected by linkages other than oxygen atoms
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Silicon Polymers (AREA)
Abstract
The application relates to a synthesis method of polycarbosilane, which comprises the steps of heating and preserving heat of an evaporation kettle in stages, so that polysilane micromolecules in the evaporation kettle are gasified according to the boiling point sequence and then enter a reaction column to carry out thermal polycondensation reaction, the molecular weight is continuously increased, a high-boiling-point product generated by the reaction returns to the evaporation kettle, and gasification is carried out after the evaporation kettle is heated to the corresponding boiling point and then enters the reaction column to carry out thermal polycondensation reaction, so that the molecular weight of the polycarbosilane can be controlled. In addition, part of polysilane micromolecules which do not react in time enter a reaction column for reflux reaction after being condensed by a condensation column, so that raw materials are fully reacted, the utilization rate of the raw materials is improved, meanwhile, reactants and product vapors are cooled in the condensation column, most of vapors are condensed into liquid except a small amount of micromolecules which cannot be liquefied at normal temperature, and the pressure in a synthesis device is obviously reduced.
Description
Technical Field
The application relates to the technical field of ceramic precursor synthesis, in particular to a synthesis method of polycarbosilane.
Background
Polycarbosilane (PCS) is a polymer with Si-C bond as a main chain, and is subjected to high-temperature pyrolysis in inert atmosphere to generate SiC ceramic, so that the SiC ceramic is widely applied to preparation of SiC ceramic fibers, siC-based ceramic matrix composite materials, high-temperature adhesives and the like. The synthesis method mainly comprises the following steps:
1) And (5) direct synthesis. J P Wesson firstly adopts organochlorosilane to condense in metal Na, K or Na/K alloy to prepare PCS; STARFIRE SYSTEM company employs a direct synthesis method to provide PCS precursors under the trade names HPCS, AHPCS. The disadvantage of the direct synthesis is the expensive raw materials, which results in an expensive PCS.
2) Thermal polycondensation process. Researchers heat tetramethylsilane in a quartz tube, and obtain series PCS with different molecular weights through thermal polycondensation; in addition to tetramethyl silicon, there are reports of the use of organochlorosilanes for pyrolytic polycondensation via LiAlH 4 And (5) reducing to obtain PCS. The method has the following defects: the molecular weight of PCS is difficult to control, the raw material of organochlorosilane is highly corrosive, and the expensive LiAlH is adopted subsequently 4 The reagent is reduced, and is not suitable for industrial production.
3) High pressure pyrolysis rearrangement. The polysilane is heat treated in an autoclave to cause structural rearrangement to PCS. This process can be regarded as an improvement of the G Fritger thermal polycondensation process, which is deficient in that: the technological parameters (470-500 ℃ and 12-15 MPa) have strict requirements on autoclave materials, and to realize amplified production (such as adopting more than 50L autoclave), expensive niobium alloy is needed to meet the requirements of temperature, pressure and volume at the same time, and general stainless steel and carbon steel materials cannot meet the requirements, so that the industrial production is limited.
4) Normal pressure pyrolysis rearrangement process
In order to solve the problem that the high-pressure pyrolysis rearrangement method is difficult to realize industrialized mass production, yang Shujin et al propose a normal-pressure synthesis method, namely, a high-temperature cracking column (the temperature is 200-700 ℃) is utilized under normal pressure, polysilane or liquid small-molecule polysilane is heated (the temperature is 150-500 ℃), and is evaporated into the cracking column to carry out reflux reaction for 30 minutes to 10 hours, so that PCS with the molecular weight of 100-2000 is obtained. The national defense science and technology university builds a device for annual production of 10 tons of PCS according to the method, but the PCS with the softening point of more than 150 ℃ can be obtained only after a single batch of production time is up to 4-5 days, the production efficiency is low, and the product price is high (about 5000 yuan per kilogram).
Disclosure of Invention
Based on this, a method of synthesizing polycarbosilane is provided so as to improve the production efficiency of polycarbosilane.
The application provides a synthesis method of polycarbosilane, which is realized by adopting a synthesis device which sequentially comprises an evaporation kettle, a reaction column and a condensation column which are connected in a sealing way from bottom to top, and comprises the following steps:
directly heating the reaction column to a preset temperature and keeping the temperature constant;
after the polysilane micromolecules are put into the evaporation kettle, air in the synthesis device is replaced by high-purity nitrogen, and the evaporation kettle is heated and insulated in stages under the protection of the high-purity nitrogen;
wherein, carry out the process that heats up and keep warm to evaporating kettle stage by stage and include:
heating the evaporation kettle from normal temperature to the temperature rise target temperature in the first stage, and then raising and keeping the temperature in stages according to a preset temperature interval, a preset temperature rise rate and a preset heat-keeping time until the highest temperature is reached;
after the process of heating and preserving heat of the evaporation kettle in stages is finished, obtaining a crude polycarbosilane product in the evaporation kettle, and purifying the crude polycarbosilane product to obtain a finished polycarbosilane product;
the internal pressure of the synthesis device in the synthesis process is not higher than 1.5MPa.
In one embodiment, the polysilane small molecules are polysilane solid powder or initially cleaved polysilane liquid small molecules;
when the polysilane micromolecules are polysilane solid powder, the temperature of the heating target in the first stage is 300 ℃;
when the polysilane small molecules are polysilane liquid small molecules, the temperature of the first stage is increased to 350 ℃.
In one embodiment, the maximum temperature of the heating and holding is determined according to the design pressure of the synthesis apparatus, and the step of determining the maximum temperature of the heating and holding is specifically as follows:
when the design pressure of the synthesis device is 0.5MPa, the highest temperature of heating is 650 ℃;
when the design pressure of the synthesis device is 1.0MPa, the highest temperature of heating is 700 ℃;
when the design pressure of the synthesis apparatus was 1.5MPa, the highest temperature of the temperature rise was 750 ℃.
In one embodiment, the preset temperature rise rate is 1-2.5℃/min, the preset incubation time is 1-3 hours, and the preset temperature interval is 50 ℃.
In one embodiment, the highest design temperature of the preset temperature of the reaction column is determined according to the design pressure of the synthesis device, and the specific steps are as follows:
when the design pressure of the synthesis device is 0.5MPa, the highest design temperature is 690-700 ℃;
when the design pressure of the synthesis device is 1.0MPa, the highest design temperature is 740-750 ℃;
when the design pressure of the synthesis device is 1.5MPa, the highest design temperature is 790-800 ℃.
In one embodiment, when the synthesis unit pressure rises to a difference from the design pressure of the synthesis unit of no more than 5-10 kPa, the inside of the synthesis unit is vented so that the pressure of the synthesis unit does not exceed the design pressure.
In one embodiment, the volume of the evaporation kettle is 50-1000L;
the diameter of the reaction column is 50-500 mm.
In one embodiment, the material of the synthesizing device is stainless steel or carbon steel;
the materials of all parts of the synthesis device are stainless steel or carbon steel;
the top of the synthesis device also comprises a pressure control and automatic exhaust device for monitoring the pressure inside the synthesis device and performing exhaust operation according to the pressure value so that the pressure in the synthesis device does not exceed the design pressure.
In one embodiment, a heating jacket containing an insulation layer is arranged on the periphery of the evaporation kettle;
the periphery of the reaction column is provided with a resistance heating sleeve containing an insulation layer;
a condensing jacket is arranged outside the condensing column; the condensing jacket comprises a water inlet and a water outlet.
In one embodiment, the condensing medium employed by the condensing column is tap water, chilled brine or chilled water.
Compared with the prior art, the application has the following beneficial effects:
1. according to the application, the temperature of the evaporation kettle is raised and kept in stages, so that polysilane micromolecules in the evaporation kettle are gasified according to the boiling point sequence and then enter the reaction column to carry out thermal polycondensation reaction, the molecular weight is continuously increased, high-boiling-point products generated by the reaction are returned to the evaporation kettle, and gasification is carried out after the evaporation kettle is heated to the corresponding boiling point and then enter the reaction column to carry out thermal polycondensation reaction, so that the molecular weight of the polycarbosilane can be controlled. In addition, part of polysilane micromolecules which do not react in time enter a reaction column for reflux reaction after being condensed by a condensation column, so that raw materials are fully reacted, the utilization rate of the raw materials is improved, meanwhile, reactants and product vapors are cooled in the condensation column, most of vapors are condensed into liquid except a small amount of micromolecules which cannot be liquefied at normal temperature, and the pressure in a synthesis device is obviously reduced (the pressure is reduced to 2-3 MPa from 12-15 MPa in a high-pressure pyrolysis rearrangement method).
2. When part of polysilane small molecules which cannot be condensed in the condensation column are accumulated at the upper part of the synthesis device, the pressure of the synthesis device is increased, and the discharge of the polysilane small molecules which cannot be condensed is controlled, so that the pressure of the synthesis device does not exceed the design pressure. The pressure in the whole synthesis device can be controlled between 0.5 and 1.5MPa through the dual functions of condensation and discharge, namely the pressure in the device is kept to be a constant value, and the pressure range is between 0.5 and 1.5MPa. The pressure of 0.5-1.5 MPa and the temperature lower than 800 ℃ can meet the use requirements, and compared with the high-pressure thermal cracking rearrangement process, the manufacturing difficulty and the manufacturing cost of equipment are obviously reduced, the manufacturing of large-volume equipment is convenient, and the production efficiency is improved. The low pressure synthesis technique has another great benefit over the high pressure pyrolysis rearrangement process: the wall thickness of the equipment can be reduced to 1/3-1/5 of that of the high-pressure method, which has remarkable effect on improving the efficiency of heating heat transfer and condensing heat transfer.
3. Compared with the normal pressure cracking rearrangement process, the low pressure synthesis technology of the application can raise the temperature of the evaporating kettle to 750 ℃ under pressure without cross-linking, coking and carbonization (the heat resistance of the molecular structure under low pressure is improved) of PCS, thereby greatly improving the participation degree of the evaporating kettle in the thermal polycondensation reaction, greatly increasing the reaction rate and obviously shortening the reaction time. Meanwhile, the temperature of the thermal polycondensation reaction column can be increased to 800 ℃ under low pressure, and the high reaction temperature and the high gas phase reactant concentration both obviously promote the polycondensation reaction.
By combining the measures, the total time from the stage heating and heat preservation to the cooling after the reaction is finished can be controlled to be 24-36 h (including the post-treatment of products), and the batch can be synthesized in 2 days, so that the production efficiency is greatly improved compared with the normal pressure synthesis process.
4. The reaction raw materials of the application can be polysilane solid powder or polysilane liquid small molecules which are subjected to preliminary cracking. When the polysilane is polysilane solid powder, the temperature of the first stage is 300 ℃ at the target temperature, so that most polysilane solid powder is converted into polysilane liquid small molecules, and then the temperature is continuously raised; when polysilane is a polysilane liquid small molecule, the temperature of the first stage is raised to a target temperature of 350 ℃, because the stage of converting solid polysilane into liquid small molecules has been passed when polysilane liquid small molecules are used as a raw material.
5. The PCS softening point produced by the normal pressure cracking process is between 130 and 190 ℃ depending on the synthesis time and the post-treatment method. The softening point of the high-pressure pyrolysis rearrangement process is 160-190 ℃. Since the higher the softening point, the higher the yield of conversion to SiC, the higher the softening point is required for PCS used in the preparation of SiC-based composites. The softening point of the PCS obtained by the low-pressure synthesis process is between 170 and 225 ℃ and the yield is between 55 and 66 percent, so that the product quality is superior to that of the existing normal-pressure and high-pressure process.
Drawings
FIG. 1 is a schematic diagram of a synthesis apparatus for polycarbosilane; wherein 1: evaporating kettle, 2: reaction column, 3: condensation column, 4: pressure control device, 5: heating jacket (containing heat preservation), 6: insulation layer, 7: resistance heating jacket (containing heat preservation), 8: and a condensing jacket.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
Comparative example 1
200g of polysilane solid powder was charged into a 1L autoclave, and after sealing, vacuum was applied to replace high purity N 2 3 times. Then directly heating to 470 ℃, and preserving heat for 10 hours, wherein the highest pressure reaches 14.5MPa. And naturally cooling after the reaction is finished, taking out a product containing two forms of solid and liquid, separating out a solid product, and dissolving the solid product in dimethylbenzene. And (3) after filtration, removing dimethylbenzene from the filtrate by reduced pressure distillation to obtain a PCS finished product.
The softening point of PCS is 182 ℃ and the synthesis yield is 54% through detection.
Comparative example 2
In a normal pressure pyrolysis rearrangement synthesis device, the volume of a reaction kettle is 50L, 22kg of polysilane solid powder is added into the reaction kettle, and the vacuum is pumped to replace high-purity N 2 Thereafter, at N 2 And heating to 480-500 ℃ for heat preservation under protection, keeping the temperature of the cracking column at 610-620 ℃, and carrying out reflux reaction for 72h. Taking out the kettle after the reaction is finishedThe solid-liquid product of (2) is filtered, then the solid product is dissolved in dimethylbenzene, filtered, and the dimethylbenzene is removed by reduced pressure distillation of the filtrate, thus obtaining the PCS finished product.
The softening point of PCS is 160 ℃ and the synthesis yield is 55% through detection.
Example 1
In a stainless steel low-pressure synthesis reaction device, 95kg of polysilane solid is put into a 200L evaporation kettle, and the device is vacuumized to replace high-purity N 2 And (3) sealing, and heating the evaporation kettle according to the following heating system:
1. the highest temperature is 650 DEG C
2. Taking 300 ℃ as a first temperature point from normal temperature to 300 ℃; taking a temperature point from 300 to 650 ℃ at intervals of 50 ℃;
3. the temperature rising rate between the temperature points is 2.5 ℃/min;
4. the heat preservation time of each temperature point is 3 hours;
the temperature of the thermal polycondensation reaction column (with the diameter of 100 mm) is 690-700 ℃, and the thermal polycondensation reaction column is kept unchanged.
The pressure in the synthesis device is controlled to be less than or equal to 0.5MPa through a pressure control and automatic exhaust device.
And taking out a solid-liquid product after the reaction is finished, dissolving the filtered solid product with dimethylbenzene, filtering, and distilling the filtrate under reduced pressure to remove the dimethylbenzene to obtain a PCS finished product.
The softening point of PCS is 172 ℃ and the yield is 55 percent.
Example 2
The synthesis reaction apparatus was the same as in example 1.
Adding 100kg of liquid polysilane into an evaporation kettle, vacuumizing the device, and replacing high-purity N 2 And closing the rear part. Heating the evaporation kettle according to the following heating system:
1. the highest temperature is 700 DEG C
2. Setting a temperature point from 350 deg.C to 700 deg.C, setting a temperature point from normal temperature to 350 deg.C and setting a temperature point of 350 deg.C
3. The temperature rise rate between the temperature points is 2.5 ℃/min. Each temperature point was incubated for 3 hours.
The temperature of the thermal polycondensation reaction column is set to 740-750 ℃ and kept unchanged.
The pressure in the synthesis device is controlled to be less than or equal to 1.0MPa.
And after the reaction is finished, taking out a solid-liquid product, filtering, dissolving the solid product in dimethylbenzene, filtering, and removing dimethylbenzene from the filtrate by reduced pressure distillation to obtain a PCS finished product.
The softening point of PCS was 190℃and the yield was 62%.
Example 3
The synthesis apparatus was the same as in example 1.
Adding 95kg of solid polysilane into a 200L evaporation kettle, vacuumizing, and replacing high-purity N 2 After 3 times the device was closed. The evaporating kettle is heated according to the following temperature rising system:
1. the maximum temperature is 750 ℃;
2. setting a temperature point from 300 ℃ to 750 ℃ every 50 ℃; setting a temperature point of 300 ℃ from normal temperature to 300 ℃;
3. the temperature rising rate between the temperature points is 2.5/min; the temperature of each temperature point is kept for 3 hours.
The temperature of the thermal polycondensation reaction column is set to 790-800 ℃ and kept unchanged.
The pressure in the synthesis device is controlled to be less than or equal to 1.5MPa.
And after the reaction is finished, taking out a solid-liquid product, filtering, dissolving the solid product in dimethylbenzene, filtering, and removing dimethylbenzene from the filtrate by reduced pressure distillation to obtain a PCS finished product.
The softening point of PCS was found to be 223℃and the yield 66%.
Under the general reaction condition, the condensation requirement can be met by adopting tap water cooling; in the case where the room temperature is high or enhanced condensation is required, ice brine, chilled water, or the like may be used as the condensing medium.
As shown in fig. 1, a schematic diagram of a synthesis apparatus of polycarbosilane is provided. Wherein 1: evaporating kettle, 2: reaction column, 3: condensation column, 4: pressure control device, 5: heating jacket (containing heat preservation), 6: insulation layer, 7: resistance heating jacket (containing heat preservation), 8: and a condensing jacket.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (7)
1. The synthesis method of the polycarbosilane is characterized by comprising the following steps of:
after polysilane is put into an evaporation kettle, air in the synthesis device is replaced by high-purity nitrogen, and the reaction column and the evaporation kettle are heated and insulated under the protection of the high-purity nitrogen; wherein, the reaction column is directly heated to a preset temperature and kept at a constant temperature; the evaporating kettle is heated and insulated in stages: heating the evaporation kettle from normal temperature to the temperature rise target temperature in the first stage, and then raising and keeping the temperature in stages according to a preset temperature interval, a preset temperature rise rate and a preset heat-keeping time until the highest temperature is reached; the preset heating rate is 1-2.5 ℃/min, the preset heat preservation time is 1-3 h, and the preset temperature interval is 50 ℃;
after the process of heating and preserving heat of the evaporation kettle in stages is finished, obtaining a crude polycarbosilane product in the evaporation kettle, and purifying the crude polycarbosilane product to obtain a finished polycarbosilane product;
the internal pressure of the synthesis device in the synthesis process is not higher than 1.5MPa;
the highest temperature of heating and heat preservation is determined according to the design pressure of the synthesis device, and the step of determining the highest temperature of heating and heat preservation is specifically as follows:
when the design pressure of the synthesis device is 0.5MPa, the highest temperature of heating is 650 ℃;
when the design pressure of the synthesis device is 1.0MPa, the highest temperature of heating is 700 ℃;
when the design pressure of the synthesis device is 1.5MPa, the highest temperature of the temperature rise is 750 ℃;
the highest design temperature of the preset temperature to which the reaction column is directly heated is determined according to the design pressure of the synthesis device, and the specific steps are as follows:
when the design pressure of the synthesis device is 0.5MPa, the highest design temperature is 690-700 ℃;
when the design pressure of the synthesis device is 1.0MPa, the highest design temperature is 740-750 ℃;
when the design pressure of the synthesis device is 1.5MPa, the highest design temperature is 790-800 ℃.
2. The method for synthesizing polycarbosilane according to claim 1, wherein the polysilane is polysilane solid powder or polysilane liquid small molecules subjected to preliminary cleavage;
when the polysilane is polysilane solid powder, the temperature of the heating target in the first stage is 300 ℃;
when the polysilane is polysilane liquid small molecules, the temperature of the first stage is increased to 350 ℃.
3. The method for synthesizing polycarbosilane according to claim 1, wherein when the pressure of the synthesizing apparatus increases to a difference of not more than 10kPa from the design pressure of the synthesizing apparatus, the inside of the synthesizing apparatus is subjected to a degassing operation so that the pressure of the synthesizing apparatus does not exceed the design pressure.
4. The method for synthesizing polycarbosilane according to claim 1, wherein the volume of the evaporation kettle is 50-1000L;
the diameter of the reaction column is 50-500 mm.
5. The method for synthesizing polycarbosilane according to claim 4, wherein the components of the synthesizing apparatus are made of stainless steel or carbon steel;
the top of the synthesis device also comprises a pressure control and automatic exhaust device which is used for monitoring the pressure inside the synthesis device and performing exhaust operation according to the pressure value so that the pressure in the synthesis device does not exceed the design pressure.
6. The method for synthesizing polycarbosilane according to claim 4, wherein a heating jacket containing an insulation layer is arranged on the periphery of the evaporation kettle;
a resistance heating sleeve containing an insulation layer is arranged on the periphery of the reaction column;
a condensing jacket is arranged outside the condensing column; the condensing jacket comprises a water inlet and a water outlet.
7. The method for synthesizing polycarbosilane according to claim 5, wherein the condensing medium used in the condensing column is tap water, brine ice or refrigerating water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310112896.1A CN116284801B (en) | 2023-02-14 | 2023-02-14 | Synthesis method of polycarbosilane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310112896.1A CN116284801B (en) | 2023-02-14 | 2023-02-14 | Synthesis method of polycarbosilane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116284801A CN116284801A (en) | 2023-06-23 |
| CN116284801B true CN116284801B (en) | 2023-10-20 |
Family
ID=86829671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310112896.1A Active CN116284801B (en) | 2023-02-14 | 2023-02-14 | Synthesis method of polycarbosilane |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116284801B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0269284A1 (en) * | 1986-11-06 | 1988-06-01 | Nippon Carbon Co., Ltd. | Method for producing organosilicon polymers |
| JPS6485225A (en) * | 1986-11-06 | 1989-03-30 | Nippon Carbon Co Ltd | Production of organosilicon polymer |
| CN102120822A (en) * | 2011-04-02 | 2011-07-13 | 中国人民解放军国防科学技术大学 | Method for synthetizing polycarbosilane under atmospheric pressure |
| CN110078926A (en) * | 2019-05-16 | 2019-08-02 | 湖南远辉新材料研究院有限公司 | A kind of high-volume high pressure synthesis method of Polycarbosilane |
| CN111019142A (en) * | 2019-12-10 | 2020-04-17 | 江苏赛菲新材料有限公司 | Improved synthesis method of polycarbosilane |
| CN113667129A (en) * | 2021-09-22 | 2021-11-19 | 湖南希里肯科技有限公司 | Spinning-grade polycarbosilane and preparation method thereof |
| JP7181435B1 (en) * | 2022-07-01 | 2022-11-30 | 株式会社クレハ | Method for producing polycarbosilane for producing silicon carbide fiber and method for producing silicon carbide fiber |
-
2023
- 2023-02-14 CN CN202310112896.1A patent/CN116284801B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0269284A1 (en) * | 1986-11-06 | 1988-06-01 | Nippon Carbon Co., Ltd. | Method for producing organosilicon polymers |
| JPS6485225A (en) * | 1986-11-06 | 1989-03-30 | Nippon Carbon Co Ltd | Production of organosilicon polymer |
| CN102120822A (en) * | 2011-04-02 | 2011-07-13 | 中国人民解放军国防科学技术大学 | Method for synthetizing polycarbosilane under atmospheric pressure |
| CN110078926A (en) * | 2019-05-16 | 2019-08-02 | 湖南远辉新材料研究院有限公司 | A kind of high-volume high pressure synthesis method of Polycarbosilane |
| CN111019142A (en) * | 2019-12-10 | 2020-04-17 | 江苏赛菲新材料有限公司 | Improved synthesis method of polycarbosilane |
| CN113667129A (en) * | 2021-09-22 | 2021-11-19 | 湖南希里肯科技有限公司 | Spinning-grade polycarbosilane and preparation method thereof |
| JP7181435B1 (en) * | 2022-07-01 | 2022-11-30 | 株式会社クレハ | Method for producing polycarbosilane for producing silicon carbide fiber and method for producing silicon carbide fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116284801A (en) | 2023-06-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102120822B (en) | Method for synthetizing polycarbosilane under atmospheric pressure | |
| JP6434986B2 (en) | Process for producing polycarbosilane-catalyzed dislocations | |
| CN109265687B (en) | Preparation method of polycarbosilane containing heterogeneous elements | |
| US20130209343A1 (en) | Liquid phase synthesis of trisilylamine | |
| CN111019142A (en) | Improved synthesis method of polycarbosilane | |
| CN116284801B (en) | Synthesis method of polycarbosilane | |
| CN108219148B (en) | High molecular weight polycarbosilane and preparation method thereof | |
| CN112608481A (en) | Polycarbosilane material and preparation method thereof | |
| EP3770151B1 (en) | Method for manufacturing chromenes by thermolysis intended for the preparation of heat-setting resins | |
| CN112209720B (en) | Carbon/silicon carbide bicontinuous phase composite material and preparation method thereof | |
| CN117363370A (en) | Mesophase pitch and continuous preparation system and method thereof | |
| CN110078926A (en) | A kind of high-volume high pressure synthesis method of Polycarbosilane | |
| CN112521613A (en) | Composite-grade polycarbosilane and preparation method thereof | |
| CN109762169B (en) | High molecular weight high linear polycarbosilane and its preparation method and use | |
| CN113667129B (en) | Spinning-grade polycarbosilane and preparation method thereof | |
| KR20200121146A (en) | Method for preparation of high purity cyclopentadiene | |
| CN108640943B (en) | Method for producing ethyl orthosilicate by using silicon powder | |
| WO2009133929A1 (en) | Method for manufacturing dialkyl zinc and dialkyl aluminum monohalide | |
| CN109942392B (en) | Preparation method of hexachloroacetone | |
| CN112813411B (en) | Preparation method of thick infrared optical material | |
| CN106633080A (en) | New process of producing polycarbosilane at medium and low pressure and production device thereof | |
| CN115044047A (en) | Polyaluminosilazane, preparation method and application | |
| CN108484484B (en) | Preparation method of 2-oxo-3-ethyl piperidinecarboxylate | |
| CN114410332A (en) | Mesophase pitch and preparation method thereof | |
| CN112830802A (en) | Preparation method of high-strength carbon fiber reinforced high-temperature composite material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |