CN113292592A - Method for removing impurities of methyldichlorosilane and silicon tetrachloride in trimethylchlorosilane - Google Patents
Method for removing impurities of methyldichlorosilane and silicon tetrachloride in trimethylchlorosilane Download PDFInfo
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Abstract
The invention relates to a method for removing methyldichlorosilane and silicon tetrachloride impurities in trimethylchlorosilane, which comprises three parts of hydrosilylation reaction, partial esterification reaction and complete esterification reaction; firstly, adding a mixture of trimethylchlorosilane containing methyldichlorosilane and silicon tetrachloride impurities and a hydrosilylation reaction product into a reactor for hydrosilylation reaction, allowing the reaction product to enter a separation system, separating the excessive reaction product and the hydrosilylation product by adopting a distillation or rectification mode, and leaving a mixture of trimethylchlorosilane and silicon tetrachloride; then adding low carbon alcohol as an esterifying agent to perform partial esterification reaction on the silicon tetrachloride in the mixture, feeding the product after the reaction into a separation system, and separating out a partial esterification product of the silicon tetrachloride by adopting a rectification mode, thereby obtaining purified trimethylchlorosilane; finally, the partial esterification product is further completely esterified into valuable tetraalkoxysilane products. Realizes the high-efficiency recovery of the trimethylchlorosilane and also realizes the high-value utilization.
Description
Technical Field
The invention belongs to the field of separation and purification of organic silicon monomers, and particularly relates to a refining technology of trimethylchlorosilane containing methyldichlorosilane and silicon tetrachloride impurities in an organic silicon synthetic monomer.
Background
The organochlorosilane is mainly produced by a direct synthesis method, the generated crude chlorosilane contains a plurality of components, and the crude chlorosilane is distilled and separated to obtain chlorosilane monomers, so that the intermediate polysiloxane of the organosilicon material is prepared, which is the most critical intermediate in the organosilicon industry. No matter which method is adopted to produce the organochlorosilane monomer, the obtained mixed product is all multi-component, and the separation and purification of the mixed monomer play an important role in the organic silicon industry and the equipment investment proportion thereof. The content and boiling point of the organosilicon monomer synthesized by the direct method and the purity of the main product are shown in table 1.
TABLE 1 Main parameters of the organosilicon monomer components synthesized by the direct method
In order to obtain high-purity organosilicon monomer products, crude chlorosilane raw materials are generally required to be separated by a rectification device with 7-10 towers. In the rectification process, products such as monomethyldichlorosilane, trimethylchlorosilane, monomethyltrichlorosilane, dimethyldichlorosilane and the like are obtained, wherein the silicon tetrachloride is obtained in the form of silicon tetrachloride-trimethylchlorosilane azeotrope, and a certain amount of monomethyldichlorosilane is contained.
As can be seen from table 1, the difference in boiling points between silicon tetrachloride and trimethylchlorosilane is only 0.3 ℃, and both form an azeotrope with 36.5 wt.% silicon tetrachloride and an azeotropic point of 53.0 ℃. Although the boiling point difference between the monomethyldichlorosilane and the trimethylchlorosilane is large, when the content of the monomethyldichlorosilane is low, the relative volatility of the monomethyldichlorosilane is less than 1.2, so that the rectification separation is difficult. When the mixture is treated by the current industrial device, the monomethyldichlorosilane is generally recovered in a first rectifying tower, and a mixture containing the incompletely recovered monomethyldichlorosilane and silicon tetrachloride-trimethylchlorosilane is obtained in a second rectifying tower. Both columns have a theoretical plate count of 100 or more and require a large reflux ratio in operation. As the mixture has no direct industrial application, great equipment investment and energy consumption are paid, part of trimethylchlorosilane is consumed, and the recovery rate of the trimethylchlorosilane is reduced.
In order to reasonably utilize the organic silicon azeotrope, chinese patent CN112028926A discloses a separation device and a separation method for removing silicon tetrachloride in the organic silicon monomer azeotrope, the separation device comprises: the first separation tower is used for separating the organic silicon monomer azeotrope; the fixed bed reactor is connected with the top of the first separation tower, and the material at the top of the first separation tower flows into the fixed bed reactor to react with the dichlorosilane product under the catalysis of the catalyst to generate trichlorosilane; and the second separation tower is connected with the fixed bed reactor, is used for separating the material flowing out of the fixed bed reactor, obtains a trimethylchlorosilane product at the tower kettle of the second separation tower, and obtains a dichlorosilane product at the tower top of the second separation tower.
Chinese patent CN111606938A provides an alcoholysis process of an organosilicon monomer azeotrope, and a method for comprehensively utilizing the organosilicon monomer azeotrope based on the alcoholysis process. The alcoholysis process is characterized in that under the vacuum condition, the azeotrope is sequentially subjected to liquid phase alcoholysis reaction and gas phase alcoholysis reaction with liquid phase alcohol and gas phase alcohol, and the process does not need to remove low boiling point substances from the azeotrope in advance, so that the aim of comprehensively utilizing the azeotrope is fulfilled.
Chinese patent CN103288865A discloses a method for producing ethyl orthosilicate by using organosilicon azeotrope, comprising: (1) heating and distilling the organic silicon azeotrope to remove fraction with boiling point lower than 40 ℃ to obtain an intermediate mixture; (2) mixing the intermediate mixture with ethanol to perform a first two-step intermittent esterification reaction, heating and distilling the reaction liquid, and collecting fractions with boiling points not less than 80 ℃; (3) and mixing the fraction with the boiling point of not less than 80 ℃ with ethanol for a second esterification reaction, and separating and purifying to obtain the tetraethoxysilane.
The prior art and the patents are based on a silicon tetrachloride-trimethylchlorosilane azeotrope obtained by multi-tower rectification and then are subjected to subsequent treatment and utilization, and the defects that the azeotrope is obtained at the cost of large equipment and energy consumption in the earlier stage, and the esterification separation azeotrope technology is based on the complete esterification of silicon tetrachloride to obtain orthosilicate, so that a certain amount of trimethylchlorosilane is subjected to alcoholysis to cause loss, and the yield of the trimethylchlorosilane is reduced. When the disproportionation reaction of dichlorosilane and silicon tetrachloride is adopted, the disproportionation reaction of methyl dichlorosilane also occurs to obtain other byproducts, and the complexity of a disproportionation reaction system and a subsequent separation process is increased.
The methyl dichlorosilane as chlorosilane containing silicon-hydrogen bond can perform hydrosilylation reaction with compound with terminal unsaturated bond, the process is simple and easy to control, the condition is mild, and a product with larger boiling point difference with the raw material can be generated by selecting a reaction medium. Silicon tetrachloride does not contain silicon hydrogen bonds, but can be esterified by using low-carbon alcohol as an esterifying agent, and can also generate a product with a large boiling point difference with the raw material. Therefore, the invention utilizes hydrosilylation and esterification reaction to react the silicon tetrachloride and the methyldichlorosilane in the mixture of the methyldichlorosilane, the silicon tetrachloride and the trimethylchlorosilane to generate a high-boiling-point compound, and the separation of the high-boiling-point compound from the trimethylchlorosilane is easy to realize, so that a refined trimethylchlorosilane product is obtained.
Disclosure of Invention
The invention aims to overcome the defects of high separation theoretical plate number and large energy consumption in the prior art on a separation and purification method of a mixture of methyldichlorosilane, silicon tetrachloride and trimethylchlorosilane. Finally, the partial esterification product is further esterified to valuable tetraalkoxysilane products.
The technical scheme of the invention is as follows:
a method for removing methyldichlorosilane and silicon tetrachloride impurities in trimethylchlorosilane comprises three parts of hydrosilylation reaction, partial esterification reaction and complete esterification reaction; firstly, adding a mixture of trimethylchlorosilane containing methyldichlorosilane and silicon tetrachloride impurities and a hydrosilylation reaction product into a reactor for hydrosilylation reaction, allowing the reaction product to enter a separation system, separating the excessive reaction product and the hydrosilylation product by adopting a distillation or rectification mode, and leaving a mixture of trimethylchlorosilane and silicon tetrachloride; then adding low carbon alcohol as an esterifying agent to perform partial esterification reaction on the silicon tetrachloride in the mixture, feeding the product after the reaction into a separation system, and separating out a partial esterification product of the silicon tetrachloride by adopting a rectification mode, thereby obtaining purified trimethylchlorosilane; finally, the partially esterified product is completely esterified to valuable tetraalkoxysilane products.
The reactants added in the partial esterification reaction and the complete esterification reaction are low-carbon alcohol.
The temperature of the partial esterification reaction is 30-100 ℃.
The complete esterification reaction is carried out by adding low carbon alcohol at 30-50 deg.C, raising reaction temperature to 90-100 deg.C, and adding excessive low carbon alcohol to fully react.
The lower alcohol is ethanol or propanol.
The concrete description is as follows:
a method for removing methyldichlorosilane and silicon tetrachloride impurities in trimethylchlorosilane mainly comprises three parts of hydrosilylation reaction, partial esterification reaction and complete esterification reaction.
(1) Allowing a mixture of trimethylchlorosilane containing methyldichlorosilane and silicon tetrachloride impurities and an added hydrosilylation reactant containing terminal unsaturated bonds to enter a hydrosilylation reactor; the obtained hydrosilylation reaction product enters a separation system; the separation system uses a simple distillation or rectification system, the boiling point difference between the hydrosilylation reaction product and the trimethylchlorosilane is relatively large, the operating conditions and the equipment requirements of the system are greatly reduced, the excessive added reactant obtained by separation returns to the hydrosilylation reactor through a pump or a compressor, the obtained addition product is sent to a product tank, and the rest mixture of the silicon tetrachloride and the trimethylchlorosilane enters a part of esterification reactor;
(2) in a partial esterification reactor, low carbon alcohol is added for partial esterification reaction of silicon tetrachloride, an esterifying agent is preferentially subjected to esterification reaction with the silicon tetrachloride in the partial esterification reactor, the addition amount of the low carbon alcohol is controlled to avoid loss caused by alcoholysis of the trimethylchlorosilane, the silicon tetrachloride is converted into an esterification product with a larger boiling point difference with the trimethylchlorosilane, the reaction temperature is 30-100 ℃, the reaction product enters a separation system, the separation system generally uses a rectifying tower system, the operating conditions and equipment requirements of the rectifying tower system are greatly reduced due to the larger boiling point difference of the partial esterification product of the silicon tetrachloride and the trimethylchlorosilane, the rectifying separation is carried out to obtain a byproduct hydrogen chloride, a trimethylchlorosilane product and a partial esterification product, and the reaction rectifying tower can also be used for integrating the reaction and the separation into one so as to save investment; partial esterification products and a small amount of unreacted low-carbon alcohol enter a complete esterification reactor.
(3) In the complete reactor, low carbon alcohol is added to carry out complete esterification reaction on partially esterified silicon tetrachloride, the low carbon alcohol is slowly added to the reaction under the condition of low temperature, then the reaction temperature is raised, excessive low carbon alcohol is continuously added to fully carry out the reaction, the reaction product enters a separation system, a rectifying tower system is generally used, and the by-product hydrogen chloride and the completely esterified silane product are obtained after rectification.
The hydrosilylation reaction, the hydrosilylation reactant containing terminal unsaturated bond can be alpha olefin/diolefin, cycloolefine, terminal olefin with benzene ring, terminal unsaturated bond compound containing nitrogen or oxygen group, alkyne, terminal olefin substituted by halogen, etc. compounds capable of generating hydrosilylation.
The reaction pressure of the hydrosilylation reaction is preferably 0 to 2.0 MPaG.
The reaction temperature of the hydrosilylation reaction is preferably 50 to 150 ℃.
The reactor form of the hydrosilylation reaction is that a homogeneous catalyst is adopted, and a stirring kettle, an external circulation reactor, a bubble column or a reaction rectifying tower are used. A fixed bed reactor was used with a heterogeneous catalyst.
The separation system after the hydrosilylation reaction comprises light component removal and heavy component removal operations, cuts fractions according to the boiling points of all components, matches and combines the fractions to respectively obtain surplus reactants and hydrosilylation products, and the rest trimethylchlorosilane and silicon tetrachloride mixture fractions.
The boiling point of the added various hydrosilylation reactants is lower than or higher than that of trimethylchlorosilane; and in order to be beneficial to separation, the product of the hydrosilylation reaction with the methyl dichlorosilane has a certain boiling point difference with the trimethyl chlorosilane.
The invention has the beneficial effects that: through the conversion reaction of impurities, a product with a larger boiling point difference with the trimethylchlorosilane is generated, the difficulty of subsequent separation operation is effectively reduced, the high-efficiency recovery of the trimethylchlorosilane is realized, the purity of the trimethylchlorosilane is more than 99.98 percent, and the yield is more than 99.2 percent. Meanwhile, the methyl dichlorosilane and the silicon tetrachloride are also converted into corresponding hydrosilylation products and orthosilicate ester compounds, so that high-value utilization can be realized. The whole process has simple process, obviously reduced equipment investment, low energy consumption, continuity, stability, environmental protection and important economic and social significance.
Drawings
FIG. 1 is a schematic flow chart of a method for removing methyldichlorosilane and silicon tetrachloride impurities from trimethylchlorosilane.
In the figure, 1-mixture starting material; 2-hydrosilylation reactant; a 3-hydrosilylation reactor; 4-hydrosilylation reaction discharging; 5-hydrosilylation reaction discharge separation system; 6-unreacted hydrosilylation reactant; 7-hydrosilylation products; 8-silicon tetrachloride and trimethylchlorosilane mixtures; 9-lower alcohol; 10-a partial esterification reactor; 11-partial esterification discharge; 12-a partial esterification product separation system; 13-hydrogen chloride; 14-trimethylchlorosilane; 15-a partial esterification product; 16-a complete esterification reactor; 17-lower alcohol; 18-discharging of complete esterification reaction; 19-a complete esterification product separation system; 20-hydrogen chloride; 21-tetraalkoxysilane.
Detailed Description
The invention is further described with reference to the following detailed description and accompanying drawings:
the mixture 1 containing methyl dichlorosilane, silicon tetrachloride and trimethylchlorosilane and an added hydrosilylation reactant 2 containing terminal unsaturated bonds enter a hydrosilylation reactor 3. The reaction pressure is 0-2.0MPaG, the reaction temperature is 50-150 ℃, and if a homogeneous catalyst such as chloroplatinic acid is adopted, the form of the reactor can be a stirred tank, an external circulation reactor, a bubble column or a reaction rectifying tower; if the catalyst is heterogeneous, a fixed bed reactor may be used. The obtained hydrosilylation reaction product 4 enters a separation system 5; the separation system 5 can use a simple distillation system or a rectification system, the boiling point difference of the hydrosilylation reaction product is relatively increased, the operating conditions and the equipment requirements of the system are greatly reduced, the excessive added reactant obtained by separation returns to the hydrosilylation reactor 3 through a pump or a compressor, the obtained addition product 7 is sent to a product tank, and the mixture 8 of the silicon tetrachloride and the trimethylchlorosilane enters an esterification reactor 10;
in a reactor 10, low carbon alcohol 9 is added to perform partial esterification reaction of silicon tetrachloride, the reaction temperature is 30-100 ℃, the molar ratio of the addition amount of the low carbon alcohol to the silicon tetrachloride is controlled below 4, the reaction product enters a separation system 12, the separation system 12 generally uses a rectification tower system, the operating conditions and equipment requirements of the rectification tower system are greatly reduced due to the large boiling point difference between the partial esterification product of the silicon tetrachloride and the trimethylchlorosilane, the rectification separation is performed to obtain by-products of hydrogen chloride 13, the trimethylchlorosilane product 14 and the partial esterification product 15, or the reaction rectification tower can be used to combine the reaction and the separation into one, so as to save investment. Partial esterification products 15 and low-carbon alcohol 17 enter a complete esterification reactor 16;
in a reactor 16, low carbon alcohol 17 is added to carry out complete esterification reaction on partially esterified silicon tetrachloride, the low carbon alcohol is slowly added under the condition of low temperature of 30-50 ℃, then the reaction temperature is raised to 90-100 ℃, excessive low carbon alcohol is continuously added to enable the reaction to be fully carried out, the reaction product enters a separation system 19, the separation system 19 generally uses a rectifying tower system, and a completely esterified product 20 and byproducts hydrogen chloride and tetraalkoxysilane 21 are obtained after rectification.
Example 1
In the application example, acetylene is used as the hydrosilylation reactant, and ethanol is used as the esterified lower alcohol. The hydrosilylation reaction formula is
SiHCH3Cl2+C2H2→CH3Si(CHCH2)Cl2
Obtaining methyl vinyl dichlorosilane;
the partial esterification reaction involved is
SiCl4+C2H5OH→SiCl3OC2H5+HCl
SiCl3OC2H5+C2H5OH→SiCl2(OC2H5)2+HCl
SiCl2(OC2H5)2+C2H5OH→SiCl(OC2H5)3+HCl
The complete esterification reaction involved is:
SiCl(OC2H5)3+C2H5OH→Si(OC2H5)4+HCl
trace amount of monomethyl trichlorosilane undergoes stepwise esterification similar to silicon tetrachloride.
(1) Hydrosilylation reaction. 5kg of raw materials are added into a 10L reaction kettle, and the raw materials comprise 5.4 percent (0.27kg) of monomethyldichlorosilane, 13.5 percent (0.67kg) of silicon tetrachloride, 80.9 percent (4.04kg) of trimethylchlorosilane and 0.2 percent (0.013kg) of monomethyltrichlorosilane. Speier catalyst containing 50 grams chloroplatinic acid was added to the reactor. Setting the reaction temperature at 80 ℃ and the reaction pressure at 0.5MPa, introducing acetylene, supplementing acetylene along with the reaction, and maintaining the reaction pressure. After 2 hours of reaction, the reaction was stopped. The conversion of monomethyldichlorosilane was 99.9%, the selectivity for the formation of methylvinyldichlorosilane was 93%, and by simple distillation, 0.307kg of methylvinyldichlorosilane having a purity of 99.9% was obtained, with no change in the amounts of silicon tetrachloride, trimethylchlorosilane and monomethyltrichlorosilane, and a total amount of 4.7 kg.
(2) 4.7kg of the intermediate product obtained in the above reaction process was added to a 15L reactor, and 5.7kg of absolute ethanol was slowly added to the reactor for reaction by using a metering pump within one hour. Along with the reaction, hydrogen chloride gas is continuously released, and a jacket is adopted to heat, so that the reaction temperature is maintained at 30 ℃. After the reaction is finished, rectifying the reaction product to obtain 4.0kg of trimethylchlorosilane, wherein the purity is 99.99 percent and the yield is 99.3 percent. 5.9kg of partial esterification products were obtained, including the esterification product of diethoxydichlorosilane, triethoxymonochlorosilane, ethyl orthosilicate and a small amount of monomethylchlorosilane.
(3) Adding part of the product after removing the trimethylchlorosilane into the reaction kettle adopted in the second step, slowly adding 1kg of ethanol within 0.5 hour, wherein the reaction temperature is 40 ℃, then raising the reaction temperature to 100 ℃, and adding 0.9kg of ethanol within 1 hour. After the reaction is finished, the esterification product is neutralized by sodium ethoxide, and is rectified to obtain 0.82kg of tetraethoxysilane with the purity of 99.5 percent and a small amount of methyltriethoxysilane product.
Example 2
In the application example, the hydrosilylation reactant adopts 3-chloropropene, and the esterified lower alcohol is ethanol. The involved hydrosilylation reaction formula is:
SiH(CH3)Cl2+C3H5Cl→Si(C3H5Cl)CH3Cl2
to obtain methyl chloropropyl dichlorosilane;
the partial esterification reaction involved is
SiCl4+C2H5OH→SiCl3OC2H5+HCl
SiCl3OC2H5+C2H5OH→SiCl2(OC2H5)2+HCl
SiCl2(OC2H5)2+C2H5OH→SiCl(OC2H5)3+HCl
The complete esterification reaction involved is:
SiCl(OC2H5)3+C2H5OH→Si(OC2H5)4+HCl
trace amount of monomethyl trichlorosilane undergoes stepwise esterification similar to silicon tetrachloride.
(1) Hydrosilylation reaction. 5kg of raw materials are added into a 10L reaction kettle, and the raw materials comprise 5.4 percent (0.27kg) of monomethyldichlorosilane, 13.5 percent (0.67kg) of silicon tetrachloride, 80.9 percent (4.04kg) of trimethylchlorosilane and 0.2 percent (0.013kg) of monomethyltrichlorosilane. Speier catalyst containing 100 grams chloroplatinic acid was added to the reactor. Setting the reaction temperature at 150 ℃ and the reaction pressure at 0.5MPa, adding 0.3kg of 3-chloropropene (excessive chemical) within 1 hour, and stopping the reaction after the total reaction time is 2 hours. The conversion of the monomethyldichlorosilane was 99.9%, the selectivity for producing the methylchlorodichlorosilane was 98.5%, and by simple distillation, 0.44kg of the methylchlorodichlorosilane having a purity of 99.9% was obtained, with no change in the amounts of silicon tetrachloride, trimethylchlorosilane and monomethyltrichlorosilane, and a total amount of 4.7 kg.
(2) 4.7kg of the intermediate product obtained in the above reaction process was added to a 15L reactor, and 5.7kg of absolute ethanol was slowly added to the reactor for reaction by using a metering pump within one hour. Along with the reaction, hydrogen chloride gas is continuously released, and a jacket is adopted to heat, so that the reaction temperature is maintained at 100 ℃. After the reaction is finished, rectifying the reaction product to obtain 4.0kg of trimethylchlorosilane, wherein the purity is 99.99 percent and the yield is 99.3 percent. 5.9kg of partial esterification products were obtained, including the esterification product of diethoxydichlorosilane, triethoxymonochlorosilane, ethyl orthosilicate and a small amount of monomethylchlorosilane.
(3) Adding part of the product after removing the trimethylchlorosilane into the reaction kettle adopted in the second step, slowly adding 1kg of ethanol within 0.5 hour, wherein the reaction temperature is 40 ℃, then raising the reaction temperature to 100 ℃, and adding 0.9kg of ethanol within 1 hour. After the reaction is finished, the esterification product is neutralized by sodium ethoxide, and is rectified to obtain 0.82kg of tetraethoxysilane with the purity of 99.4 percent and a small amount of methyltriethoxysilane product.
Example 3
In the application example, styrene is used as the hydrosilylation reactant, and n-propanol is used as the esterified lower alcohol. The involved hydrosilylation reaction formula is:
HSiCH3Cl2+PhCH＝CH2→CH3(PhCH2CH2)SiCl2
obtaining methyl ethyl phenyl dichlorosilane;
the partial esterification reaction involved is
SiCl4+C3H7OH→SiCl3OC3H7+HCl
SiCl3OC3H7+C3H7OH→SiCl2(OC3H7)2+HCl
SiCl2(OC3H7)2+C3H7OH→SiCl(OC3H7)3+HCl
The complete esterification reaction involved is:
SiCl(OC3H7)3+C3H7OH→Si(OC3H7)4+HCl
trace amount of monomethyl trichlorosilane undergoes stepwise esterification similar to silicon tetrachloride.
(1) Hydrosilylation reaction. 5kg of raw materials are added into a 10L reaction kettle, and the raw materials comprise 5.4 percent (0.27kg) of monomethyldichlorosilane, 13.5 percent (0.67kg) of silicon tetrachloride, 80.9 percent (4.04kg) of trimethylchlorosilane and 0.2 percent (0.013kg) of monomethyltrichlorosilane. Speier catalyst containing 120 grams chloroplatinic acid was added to the reactor. The reaction temperature was set at 100 ℃ and the reaction pressure was set at 1.0MPa, 0.5kg of styrene (stoichiometric excess) was added over 1 hour, and the reaction was stopped after 2 hours total reaction time. The conversion of monomethyldichlorosilane was 99.7%, the selectivity for the formation of methylethylphenyldichlorosilane was 98.4%, and by simple distillation, 0.51kg of methylphenethyldichlorosilane having a purity of 99.8% was obtained, with no change in the amounts of silicon tetrachloride, trimethylchlorosilane and monomethyltrichlorosilane, and a total amount of 4.7 kg.
(2) 4.7kg of the intermediate product obtained in the above reaction process was added to a 15L reactor, and 7.4kg of n-propanol was slowly added to the reactor for reaction by using a metering pump within one hour. Along with the reaction, hydrogen chloride gas is continuously released, and a jacket is adopted to heat, so that the reaction temperature is maintained at 50 ℃. After the reaction is finished, rectifying the reaction product to obtain 4.0kg of trimethylchlorosilane, wherein the purity is 99.98 percent and the yield is 99.2 percent. 6.2kg of partial esterification products were obtained, including the esterification product of dipropoxydichlorosilane, tripropoxymonochlorosilane, propyl orthosilicate and a small amount of monomethylchlorosilane.
(3) Adding part of the product after removing the trimethylchlorosilane into a reaction kettle adopted in the second step, slowly adding 1.3kg of n-propanol within 0.5 hour, wherein the reaction temperature is 30 ℃, then raising the reaction temperature to 100 ℃, and adding 1.2kg of n-propanol within 1 hour. After the reaction is finished, the esterification product is neutralized by sodium propoxide, and is rectified to obtain 1.04kg of n-propyl orthosilicate with the purity of 99.5 percent and a small amount of methyl tripropoxysilane product.
Example 4
In the application example, ethylene is used as the hydrosilylation reactant, and n-propanol is used as the esterified lower alcohol. The involved hydrosilylation reaction formula is:
HSiCH3Cl2+C2H4→CH3Si(CH2CH3)Cl2
obtaining methyl ethyl dichlorosilane;
the partial esterification reaction involved is
SiCl4+C2H5OH→SiCl3OC2H5+HCl
SiCl3OC2H5+C2H5OH→SiCl2(OC2H5)2+HCl
SiCl2(OC2H5)2+C2H5OH→SiCl(OC2H5)3+HCl
The complete esterification reaction involved is:
SiCl(OC2H5)3+C2H5OH→Si(OC2H5)4+HCl
trace amount of monomethyl trichlorosilane undergoes stepwise esterification similar to silicon tetrachloride.
(1) Hydrosilylation reaction. 5kg of raw materials are added into a 10L reaction kettle, and the raw materials comprise 5.4 percent (0.27kg) of monomethyldichlorosilane, 13.5 percent (0.67kg) of silicon tetrachloride, 80.9 percent (4.04kg) of trimethylchlorosilane and 0.2 percent (0.013kg) of monomethyltrichlorosilane. Speier catalyst containing 80 grams of chloroplatinic acid was added to the reactor. Setting the reaction temperature at 50 deg.c and the reaction pressure at 0MPa, introducing ethylene, replenishing ethylene and maintaining the reaction pressure. After 2 hours of reaction, the reaction was stopped. The conversion of monomethyldichlorosilane was 99.6%, the selectivity for the formation of methylvinyldichlorosilane was 95%, and by simple distillation, 0.335kg of methylethyldichlorosilane having a purity of 99.9% was obtained, with no change in the amounts of silicon tetrachloride, trimethylchlorosilane and monomethyltrichlorosilane, and a total amount of 4.7 kg.
(2) 4.7kg of the intermediate product obtained in the above reaction process was added to a 15L reactor, and 5.7kg of absolute ethanol was slowly added to the reactor for reaction by using a metering pump within one hour. Along with the reaction, hydrogen chloride gas is continuously released, and a jacket is adopted to heat, so that the reaction temperature is maintained at 40 ℃. After the reaction is finished, rectifying the reaction product to obtain 4.0kg of trimethylchlorosilane, wherein the purity is 99.99 percent and the yield is 99.4 percent. 5.9kg of partial esterification products were obtained, including the esterification product of diethoxydichlorosilane, triethoxymonochlorosilane, ethyl orthosilicate and a small amount of monomethylchlorosilane.
(3) Adding part of the product after removing the trimethylchlorosilane into the reaction kettle adopted in the second step, slowly adding 1kg of ethanol within 0.5 hour, wherein the reaction temperature is 50 ℃, then raising the reaction temperature to 90 ℃, and adding 0.9kg of ethanol within 1 hour. After the reaction is finished, the esterification product is neutralized by sodium ethoxide, and is rectified to obtain 0.81kg of tetraethoxysilane with the purity of 99.6 percent and a small amount of methyltriethoxysilane product.
Example 5
In the application example, acrylonitrile is used as the hydrosilylation reactant, and n-propanol is used as the esterified lower alcohol. The involved hydrosilylation reaction formula is:
HSiCH3Cl2+CH2＝CHCN→CH3Si(CH2CH2CN)Cl2
to obtain methyl cyanopropyl dichlorosilane;
the partial esterification reaction involved is
SiCl4+C2H5OH→SiCl3OC2H5+HCl
SiCl3OC2H5+C2H5OH→SiCl2(OC2H5)2+HCl
SiCl2(OC2H5)2+C2H5OH→SiCl(OC2H5)3+HCl
The complete esterification reaction involved is:
SiCl(OC2H5)3+C2H5OH→Si(OC2H5)4+HCl
trace amount of monomethyl trichlorosilane undergoes stepwise esterification similar to silicon tetrachloride.
(1) Hydrosilylation reaction. 5kg of raw materials are added into a 10L reaction kettle, and the raw materials comprise 5.4 percent (0.27kg) of monomethyldichlorosilane, 13.5 percent (0.67kg) of silicon tetrachloride, 80.9 percent (4.04kg) of trimethylchlorosilane and 0.2 percent (0.013kg) of monomethyltrichlorosilane. Speier catalyst containing 60 grams of chloroplatinic acid was added to the reactor. The reaction temperature was set at 90 ℃ and the reaction pressure at 2.0MPa, 0.2kg of acrylonitrile (excess chemical) was added over 1 hour, and the reaction was stopped after 2 hours total reaction time. The conversion of monomethyldichlorosilane was 99.9%, the selectivity for the formation of methylcyanopropyldichlorosilane was 95.7%, and by simple distillation, 0.39kg of methylcyanopropyldichlorosilane having a purity of 99.9% was obtained, with no change in the amounts of silicon tetrachloride, trimethylchlorosilane and monomethyltrichlorosilane, and a total amount of 4.7 kg.
(2) 4.7kg of the intermediate product obtained in the above reaction process was added to a 15L reactor, and 5.7kg of absolute ethanol was slowly added to the reactor for reaction by using a metering pump within one hour. Along with the reaction, hydrogen chloride gas is continuously released, and a jacket is adopted to heat, so that the reaction temperature is maintained at 40 ℃. After the reaction is finished, rectifying the reaction product to obtain 4.0kg of trimethylchlorosilane, wherein the purity is 99.98 percent and the yield is 99.3 percent. 5.9kg of partial esterification products were obtained, including the esterification product of diethoxydichlorosilane, triethoxymonochlorosilane, ethyl orthosilicate and a small amount of monomethylchlorosilane.
(3) Adding part of the product after removing the trimethylchlorosilane into the reaction kettle adopted in the second step, slowly adding 1kg of ethanol within 0.5 hour, wherein the reaction temperature is 50 ℃, then raising the reaction temperature to 100 ℃, and adding 0.9kg of ethanol within 1 hour. After the reaction is finished, the esterification product is neutralized by sodium ethoxide, and is rectified to obtain 0.81kg of tetraethoxysilane with the purity of 99.4 percent and a small amount of methyltriethoxysilane product.
While the methods and techniques of the present invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and/or modifications of the methods and techniques described herein may be made without departing from the spirit and scope of the invention. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and content of the invention.
Claims (7)
1. A method for removing methyldichlorosilane and silicon tetrachloride impurities in trimethylchlorosilane is characterized by comprising three parts of hydrosilylation reaction, partial esterification reaction and complete esterification reaction; firstly, adding a mixture of trimethylchlorosilane containing methyldichlorosilane and silicon tetrachloride impurities and a hydrosilylation reaction product into a reactor for hydrosilylation reaction, allowing the reaction product to enter a separation system, separating the excessive reaction product and the hydrosilylation product by adopting a distillation or rectification mode, and leaving a mixture of trimethylchlorosilane and silicon tetrachloride; then adding low carbon alcohol as an esterifying agent to perform partial esterification reaction on the silicon tetrachloride in the mixture, feeding the product after the reaction into a separation system, and separating out a partial esterification product of the silicon tetrachloride by adopting a rectification mode, thereby obtaining purified trimethylchlorosilane; finally, the partially esterified product is completely esterified to valuable tetraalkoxysilane products.
2. The process of claim 1, wherein the reactants for the partial esterification and the complete esterification are lower alcohols such as ethanol or propanol.
3. The process of claim 1, wherein the partial esterification reaction temperature is from 30 ℃ to 100 ℃.
4. The method of claim 1, wherein the complete esterification is carried out by adding lower alcohol at 30-50 deg.C, raising the reaction temperature to 90-100 deg.C, and adding excessive lower alcohol to fully react.
5. The method according to claim 1, wherein the lower alcohol is ethanol or propanol.
6. The process of claim 1 wherein the hydrosilylation reaction is carried out at a pressure of 0 to 2.0 MPaG; the reaction temperature is 50-150 ℃.
7. The method of claim 1, wherein the hydrosilylation reaction, the hydrosilylation reactant containing terminal unsaturation is an alpha olefin/diolefin, a cyclic olefin, a terminal olefin having a benzene ring, a compound containing terminal unsaturation of a nitrogen or oxygen containing group, an alkyne, a compound capable of hydrosilylation of a halogen substituted terminal olefin.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1090579A (en) * | 1992-12-03 | 1994-08-10 | 瓦克化学有限公司 | From methyl chlorosilane, remove the method for silane containing hydrogen |
| US20030100784A1 (en) * | 2001-10-10 | 2003-05-29 | Degussa Ag | Process for the hydrosilylation of unsaturated aliphatic compounds |
| CN103288865A (en) * | 2013-05-31 | 2013-09-11 | 浙江合盛硅业有限公司 | Method for producing tetraethyl orthosilicate by use of organic silicon azeotrope |
| CN103319519A (en) * | 2013-05-31 | 2013-09-25 | 浙江合盛硅业有限公司 | Method for producing hexamethyldisiloxane by utilization of organosilicon azeotrope |
| CN104945428A (en) * | 2015-05-22 | 2015-09-30 | 嘉兴学院 | Method for preparing dimethyl dichlorosilane |
-
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- 2021-06-08 CN CN202110635806.8A patent/CN113292592B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1090579A (en) * | 1992-12-03 | 1994-08-10 | 瓦克化学有限公司 | From methyl chlorosilane, remove the method for silane containing hydrogen |
| US20030100784A1 (en) * | 2001-10-10 | 2003-05-29 | Degussa Ag | Process for the hydrosilylation of unsaturated aliphatic compounds |
| CN103288865A (en) * | 2013-05-31 | 2013-09-11 | 浙江合盛硅业有限公司 | Method for producing tetraethyl orthosilicate by use of organic silicon azeotrope |
| CN103319519A (en) * | 2013-05-31 | 2013-09-25 | 浙江合盛硅业有限公司 | Method for producing hexamethyldisiloxane by utilization of organosilicon azeotrope |
| CN104945428A (en) * | 2015-05-22 | 2015-09-30 | 嘉兴学院 | Method for preparing dimethyl dichlorosilane |
Non-Patent Citations (1)
| Title |
|---|
| 成都工学院主编: "《塑料工艺学》", 31 August 1961, 北京：中国工业出版社 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114524839A (en) * | 2022-01-12 | 2022-05-24 | 湖北江瀚新材料股份有限公司 | Preparation method of stearyloxy trimethylsilane |
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