Preparation method of electronic-grade methyldiethoxysilane

Abstract

The invention discloses a preparation method of electronic-grade methyldiethoxysilane, which comprises the following steps: (a) adding industrial-grade methyldiethoxysilane into a first rectifying tower, carrying out primary rectification heavy component removal treatment, introducing the obtained product into a condenser from the tower top, then entering a second rectifying tower, and carrying out primary light component removal treatment to obtain a rectification treatment product; (b) the rectification treatment product is introduced into an adsorption tank for impurity adsorption, and after adsorption is completed, an adsorption treatment product is obtained; and (c) introducing the adsorption treatment product into a third rectifying tower, carrying out secondary rectification heavy component removal treatment, introducing the obtained product into a condenser from the tower top, then entering a fourth rectifying tower, and carrying out secondary light component removal treatment, so as to obtain the electronic-grade methyldiethoxysilane. Wherein the adsorption tank is filled with a modified adsorbent. According to the method, most impurities in methyldiethoxysilane are removed through a method of combining rectification and adsorption, and the product of the electronic-grade methyldiethoxysilane with the purity of 99.9% or above is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of methyldiethoxysilane purification, and particularly relates to a method for preparing electronic-grade methyldiethoxysilane. Background Art

[0002] Methyldiethoxysilane is an important organosilicon intermediate for the synthesis of modified silicone oil and modified resin. Its molecular structure contains both hydrolyzable silylethoxy groups and active silicon-hydrogen (Si-H) bonds. Through the silicon-hydrogen bonds, it undergoes a silicon-hydrogen addition reaction with olefin monomers in the presence of a platinum catalyst to introduce different functional groups to obtain various silane coupling agents. If used as an end-capping group for polyether, the base adhesive of organosilicon-modified polyether sealant can be obtained.

[0003] The synthesis of methyldiethoxysilane has been industrialized abroad. Foreign researchers use sodium alcoholate method, continuous alcoholysis-stripping method, falling film continuous gas-liquid phase alcoholysis and high-low boiling solvent method. However, there are few reports on the synthesis of methyldiethoxy in China. Hu Biru et al. used intermittent solvent method and continuous solvent-free gas-liquid phase method respectively, and the yield of methyldiethoxysilane did not exceed 80%.

[0004] In the prior art, a continuous esterification method is used to fully react methyldichlorosilane with ethanol in a tower reactor, and hydrogen chloride gas is discharged from the top of the tower, and a crude methyldiethoxysilane product is obtained at the bottom of the tower, and the product can be obtained by further distillation, separation and purification. The raw materials of this method are easy to obtain and the cost is low, but a large amount of hydrogen chloride as a by-product of the reaction will cause equipment corrosion, and the low-boiling point raw materials are easy to block the absorption tower, forming a large amount of silicon slag that is difficult to remove; at the same time, in the presence of hydrogen chloride, the silicon-hydrogen bond in methyldiethoxysilane is easily hydrolyzed by ethanol to generate a by-product methyltriethoxysilane and release hydrogen, which poses a safety hazard; and the water generated by the reaction of hydrogen chloride that is not discharged in time with ethanol will cause the product to hydrolyze and polycondense, which seriously affects the content of the target product, so there are still many difficulties in applying this method to industrial production. Methyldiethoxysilane can also be obtained by depolymerizing hydrogen-containing polysilane with alkoxysilane. Hydrogen-containing silicone oil and methyltriethoxysilane are mixed and reacted at 100℃ to 200℃ under the catalysis of tetrabutoxyzirconium for about 3 hours. During the reaction, the product is quickly distilled off to inhibit side reactions. The 94℃ to 95℃ fraction is collected as the methyldiethoxysilane product. This method is simple in process, no corrosive substances are produced, and the content can reach more than 57%. However, the reaction will produce a large amount of high-boiling products that are difficult to handle. At the same time, due to the high-temperature reaction, the high energy consumption is also a problem that cannot be ignored. Industrial production still faces some difficulties that need to be solved urgently.

[0005] The organic silicon raw materials used in integrated circuit manufacturing must reach electronic grade, but the general commercial methyldiethoxysilane content is only 99% after ordinary purification, and contains impure metal ions, which will have a serious impact on the manufacture of integrated circuit materials.

[0006] Chinese patent CN114989208A discloses a methyldiethoxysilane and a preparation method, wherein the preparation method comprises: S1. Add 1,3,5,7-tetramethylcyclotetrasiloxane, a catalyst and an initiator into a reactor, start stirring and heating, and start dripping triethyl orthoformate after reaching the reaction temperature to start the reaction; S2. After the dripping of triethyl orthoformate is completed, adjust the temperature to a specified temperature, continue the reaction to obtain a mixture; S3. Distill and separate the obtained mixture to obtain methyldiethoxysilane. This method is non-corrosive to equipment, has high conversion rate, high product content, high product quality, simple process operation, mild reaction conditions, low pollution, low equipment investment, and is suitable for industrial production. However, the purity of the methyldiethoxysilane finally obtained by the patent is only 98.3% at most, which cannot meet the requirements of electronic grade silane.

[0007] Therefore, there is an urgent need in the art for a method for preparing electronic-grade methyldiethoxysilane. Summary of the invention

[0008] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing electronic-grade methyldiethoxysilane, which removes most of the impurities such as methyltriethoxysilane and metal ions in methyldiethoxy by combining distillation and adsorption, thereby obtaining electronic-grade methyldiethoxysilane, that is, a product with a purity of more than 99.9%.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0011] (a) adding industrial grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, and introducing the obtained product into a condenser from the tower top, and then entering a second distillation tower, performing a de-light treatment, and obtaining a distillation product;

[0012] (b) introducing the distillation product in step (a) into an adsorption tank to adsorb impurities, and after the adsorption is completed, an adsorption product is obtained;

[0013] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and heavy removal treatment, and introducing the obtained product into a condenser from the top of the tower, and then entering a fourth distillation tower for secondary light removal treatment to obtain the electronic grade methyldiethoxysilane;

[0014] Wherein, the adsorption tank is filled with modified adsorbent.

[0015] In step (a), the number of theoretical plates of the first distillation tower is 30-60, the top pressure is 0.08-0.12 MPa, the top temperature is 102-106°C, the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 120-130°C; the number of theoretical plates of the second distillation tower is 50-70, the top pressure is 0.06-0.11 MPa, and the top temperature is 98-103°C; the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 105-110°C.

[0016] In the present invention, most of the high-boiling impurities such as methyltriethoxysilane can be removed by first subjecting industrial-grade methyldiethoxysilane to distillation and de-heavy treatment, and then de-light treatment is performed to remove low-boiling impurities to obtain a product after distillation treatment.

[0017] Preferably, the temperature of the adsorption tank in step (b) is 50-60° C., and the adsorption time is 1-2 h.

[0018] More preferably, the temperature of the adsorption tank in step (b) is 55-60° C., and the adsorption time is 1-1.5 h.

[0019] In the present invention, the distillation product is subjected to adsorption treatment to remove residual metal ions in methyldiethoxysilane.

[0020] Preferably, the third distillation tower in step (c) has a theoretical plate number of 40-50, a top pressure of 0.08-0.12 MPa, a top temperature of 102-106°C, a bottom pressure of 0.05-0.1 MPa, and a bottom temperature of 120-130°C; the fourth distillation tower has a theoretical plate number of 60-70, a top pressure of 0.06-0.11 MPa, and a top temperature of 98-103°C; the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 105-110°C.

[0021] In the present invention, the product after the adsorption treatment is subjected to a distillation treatment to remove heavy and light components again, and the methyldiethoxysilane after the adsorption treatment is further purified to obtain electronic grade methyldiethoxysilane.

[0022] Preferably, the method for preparing the modified adsorbent comprises the following steps:

[0023] S1, adding activated carbon powder to an acidic manganese permanganate solution for impregnation treatment, filtering and drying after the treatment, and then roasting in an ammonia atmosphere, and obtaining pretreated activated carbon after the roasting;

[0024] S2, adding the pretreated activated carbon in step S1 to dimethylformamide, and then adding 2,5-thiophenedicarboxylic acid, 2-mercapto-6-chlorobenzothiazole, and triethylamine, stirring to react, and filtering, washing, and drying after the reaction is completed to obtain modified activated carbon;

[0025] S3, adding chitosan to the acetic acid solution, stirring and dissolving to obtain a chitosan solution, then adding the modified activated carbon in step S2, and reacting at a constant temperature under a nitrogen atmosphere, controlling the pH value between 8 and 9 during the reaction, filtering, washing and drying after the reaction is completed to obtain the modified adsorbent.

[0026] Preferably, the concentration of potassium permanganate in the acidic potassium permanganate solution in step S1 is 30-50 g / L, and the pH is 1-2; the immersion temperature is 40-50° C., and the time is 2-3 h; the calcination temperature is 600-700° C., and the time is 1-2 h.

[0027] More preferably, the concentration of potassium permanganate in the acidic potassium permanganate solution in step S1 is 40-50 g / L, and the pH is 1-1.5; the immersion temperature is 45-50° C., and the time is 2-2.5 h; and the calcination temperature is 650-700° C., and the time is 1-1.5 h.

[0028] In the present invention, activated carbon is used as an adsorption carrier. It has the characteristics of high specific surface area, high porosity, suitable pore size, surface morphology and adjustable functional group properties, and is a very potential adsorbent material. However, due to the structural characteristics and properties of the activated carbon itself, its adsorption performance for metal ions is poor. By modifying it, the activated carbon is first subjected to acidification and oxidation treatment to increase the active oxygen groups on its surface, and then calcined in an ammonia atmosphere so that the surface of the activated carbon has more amino groups, which not only improves its adsorption for metal ions, but also facilitates the subsequent reactions.

[0029] Preferably, the mass ratio of the pretreated activated carbon, 2,5-thiophenedicarboxylic acid, 2-mercapto-6-chlorobenzothiazole, and triethylamine in step S2 is 100:10-20:12-24:30-40.

[0030] More preferably, the mass ratio of the pretreated activated carbon, 2,5-thiophenedicarboxylic acid, 2-mercapto-6-chlorobenzothiazole, and triethylamine in step S2 is 100:15-20:18-24:35-40.

[0031] Preferably, the stirring reaction in step S2 is carried out at a temperature of 70-80° C. and for a time of 2-4 h.

[0032] More preferably, the stirring reaction in step S2 is carried out at a temperature of 75-80° C. and for a time of 2-3 h.

[0033] In the present invention, the aminated activated carbon is reacted with 2,5-thiophenedicarboxylic acid and 2-mercapto-6-chlorobenzothiazole to introduce thiophene groups and benzothiazole groups onto the surface of the activated carbon, thereby improving the adsorption of metal ions by the activated carbon.

[0034] Preferably, the mass concentration of the acetic acid solution in step S3 is 5-10%, the mass ratio of chitosan, acetic acid solution and modified activated carbon is 5-10:800-1000:70-90; the temperature of the isothermal reaction is 80-90°C and the time is 7-10h.

[0035] More preferably, the mass concentration of the acetic acid solution in step S3 is 8-10%, the mass ratio of chitosan, acetic acid solution and modified activated carbon is 7-10:900-1000:80-90; the temperature of the isothermal reaction is 85-90°C and the time is 7-9h.

[0036] In the present invention, activated carbon containing benzothiazole groups is reacted with chitosan to introduce chitosan onto the surface of the activated carbon. Chitosan molecules contain multiple active functional groups such as hydroxyl groups, amino groups and glycosidic bonds, which have a good adsorption effect on metal ions, thereby significantly improving the adsorption effect of the modified adsorbent on metal ions.

[0037] Preferably, the specific step of controlling the pH in step S4 is: adding a 5% by mass NaOH solution every 1 hour of reaction to adjust the pH to 8-9.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The preparation method of electronic-grade methyldiethoxysilane provided by the present invention comprises treating industrial-grade methyldiethoxysilane by distillation-adsorption-re-distillation, performing a first distillation to remove heavy and light impurities to remove most high-boiling impurities such as methyltriethoxysilane and low-boiling impurities, and then performing an adsorption treatment to remove residual metal ions in the methyldiethoxysilane. After the adsorption is completed, a second distillation to remove heavy and light impurities is performed to obtain electronic-grade methyldiethoxysilane, that is, a product with a purity of more than 99.9%.

[0040] (2) The preparation method of electronic grade methyldiethoxysilane provided by the present invention, the added adsorbent is activated carbon as a carrier, the activated carbon is first subjected to acidification and oxidation treatment to increase the active oxygen groups on its surface, and then calcined in an ammonia atmosphere to introduce amino groups on the surface of the activated carbon, which not only improves the performance of the activated carbon in adsorbing metal ions, but also facilitates the subsequent reaction; then the pretreated activated carbon is reacted with 2,5-thiophenedicarboxylic acid and 2-mercapto-6-chlorobenzothiazole to introduce thiophene groups and benzothiazole groups on its surface, the heterocyclic sulfur atom in the thiophene group has a strong coordination ability and can form a coordination bond with the metal ion, thereby improving the selective adsorption of metal ions by the activated carbon; at the same time, the nitrogen atom and the sulfur atom in the thiazole group have solitary The invention has good electrophilicity and coordination ability for electrons, and can form coordination bonds with metal ions, thereby further improving the ability of activated carbon to adsorb metal ions; finally, the activated carbon is reacted with chitosan, and the chlorine atom groups in 2-mercapto-6-chlorobenzothiazole can undergo substitution reaction with the hydroxyl and amino groups in chitosan, and the surface of the activated carbon is connected with chitosan, and chitosan has a good adsorption effect on metal ions, which significantly improves the adsorption effect of the modified adsorbent on metal ions; the invention introduces sulfur-containing and nitrogen-containing heterocyclic compounds and chitosan into the surface of the activated carbon by a chemical grafting method, which not only improves the ability of the activated carbon to adsorb metal ions, but also ensures that no secondary pollution is caused during the adsorption process, thereby improving the purity of methyldiethoxysilane to reach the electronic grade. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the present invention, the activated carbon is purchased from Jiangsu COSCO Activated Carbon Co., Ltd., with a mesh size of 200-300 mesh and a specific surface area of ​​800-900m 2 / g; the chitosan was purchased from Xi'an Tianzheng Pharmaceutical Excipients Co., Ltd., with a deacetylation degree of 65%.

[0043] Example 1

[0044] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0045] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 50, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.09 MPa, and the tower top temperature is 99° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., and a distillation treatment product is obtained;

[0046] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 55° C., and after adsorption for 1.5 hours, an adsorption product is obtained;

[0047] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 45, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., and the obtained product is introduced into a condenser from the tower top, and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 65, the tower top pressure is 0.1 MPa, and the tower top temperature is 98° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., thereby obtaining the electronic grade methyldiethoxysilane;

[0048] Wherein, the adsorption tank is filled with a modified adsorbent;

[0049] The preparation method of the modified adsorbent comprises the following steps:

[0050] S1, 100g activated carbon powder was added to 800mL acidic manganese permanganate solution (potassium permanganate concentration is 40g / L, pH is 1.5), and immersed at 45°C for 2.5h. After the treatment, it was filtered and dried, and then calcined in an ammonia atmosphere at a temperature of 50°C for 1.5h. After the calcination, pretreated activated carbon was obtained;

[0051] S2, adding 100g of pretreated activated carbon in step S1 to 1L of dimethylformamide, then adding 15g of 2,5-thiophenedicarboxylic acid, 18g of 2-mercapto-6-chlorobenzothiazole, and 35g of triethylamine, stirring and reacting at 75°C for 3h, filtering, washing, and drying after the reaction is completed to obtain modified activated carbon;

[0052] S3, adding 8g of chitosan to 900g of 10% acetic acid solution, stirring and dissolving to obtain a chitosan solution, then adding 80g of modified activated carbon in step S2, and reacting at 85°C for 9h under a nitrogen atmosphere. During the reaction, adding 5% NaOH solution every 1h to adjust the pH to 8.5. After the reaction is completed, filtering, washing and drying are performed to obtain the modified adsorbent.

[0053] In this embodiment, the purity of the industrial-grade methyldiethoxysilane raw material is 92.6%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.97%.

[0054] Example 2

[0055] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0056] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 40, the tower top pressure is 0.09 MPa, the tower top temperature is 104° C., the tower bottom pressure is 0.07 MPa, and the tower bottom temperature is 125° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.08 MPa, and the tower top temperature is 100° C.; the tower bottom pressure is 0.07 MPa, and the tower bottom temperature is 107° C., and a distillation treatment product is obtained;

[0057] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 55° C., and after adsorption for 1.5 hours, an adsorption product is obtained;

[0058] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 45, the tower top pressure is 0.09 MPa, the tower top temperature is 103°C, the tower bottom pressure is 0.07 MPa, and the tower bottom temperature is 125°C. The obtained product is introduced into a condenser from the tower top and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 65, the tower top pressure is 0.08 MPa, and the tower top temperature is 100°C; the tower bottom pressure is 0.07 MPa, and the tower bottom temperature is 107°C, thereby obtaining the electronic grade methyldiethoxysilane;

[0059] Wherein, the adsorption tank is filled with a modified adsorbent;

[0060] The preparation method of the modified adsorbent comprises the following steps:

[0061] S1, 100g activated carbon powder was added to 800mL acidic manganese permanganate solution (potassium permanganate concentration is 45g / L, pH is 1.5), and immersed at 45°C for 2.5h. After the treatment, it was filtered and dried, and then calcined in an ammonia atmosphere at a temperature of 650°C for 1.5h. After the calcination, pretreated activated carbon was obtained;

[0062] S2, adding 100g of pretreated activated carbon in step S1 to 1L of dimethylformamide, then adding 15g of 2,5-thiophenedicarboxylic acid, 18g of 2-mercapto-6-chlorobenzothiazole, and 35g of triethylamine, stirring and reacting at 75°C for 3h, filtering, washing, and drying after the reaction is completed to obtain modified activated carbon;

[0063] S3, adding 7g of chitosan to 900g of acetic acid solution with a mass concentration of 5%, stirring to dissolve, to obtain a chitosan solution, then adding 80g of the modified activated carbon in step S2, and reacting at 85°C for 8h under a nitrogen atmosphere. During the reaction, adding a 5% NaOH solution every 1h to adjust the pH to 8.5. After the reaction is completed, filtering, washing and drying are performed to obtain the modified adsorbent.

[0064] In this embodiment, the purity of the industrial-grade methyldiethoxysilane raw material is 93.1%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.95%.

[0065] Example 3

[0066] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0067] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 30, the tower top pressure is 0.08 MPa, the tower top temperature is 102° C., the tower bottom pressure is 0.05 MPa, and the tower bottom temperature is 120° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 50, the tower top pressure is 0.06 MPa, and the tower top temperature is 98° C.; the tower bottom pressure is 0.05 MPa, and the tower bottom temperature is 105° C., and a distillation treatment product is obtained;

[0068] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 50° C., and after adsorption for 2 hours, an adsorption product is obtained;

[0069] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 40, the tower top pressure is 0.08 MPa, the tower top temperature is 102°C, the tower bottom pressure is 0.05 MPa, and the tower bottom temperature is 120°C. The obtained product is introduced into a condenser from the tower top, and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.06 MPa, and the tower top temperature is 98°C; the tower bottom pressure is 0.05 MPa, and the tower bottom temperature is 105°C, thereby obtaining the electronic grade methyldiethoxysilane;

[0070] Wherein, the adsorption tank is filled with a modified adsorbent;

[0071] The preparation method of the modified adsorbent comprises the following steps:

[0072] S1, 100g activated carbon powder was added to 800mL of acidic manganese permanganate solution (the concentration of potassium permanganate was 30g / L and the pH was 1), and the mixture was immersed in 40°C for 3h. After the treatment, the mixture was filtered and dried, and then calcined in an ammonia atmosphere at a temperature of 600°C for 2h. After the calcination, pretreated activated carbon was obtained;

[0073] S2, adding 100g of pretreated activated carbon in step S1 to 1L of dimethylformamide, then adding 10g of 2,5-thiophenedicarboxylic acid, 12g of 2-mercapto-6-chlorobenzothiazole, and 30g of triethylamine, stirring and reacting at 70°C for 4h, filtering, washing, and drying after the reaction is completed to obtain modified activated carbon;

[0074] S3, adding 5g of chitosan to 800g of acetic acid solution with a mass concentration of 5%, stirring to dissolve, to obtain a chitosan solution, then adding 70g of modified activated carbon in step S2, and reacting at 80°C for 10h under a nitrogen atmosphere. During the reaction, adding a 5% NaOH solution every 1h to adjust the pH to 8. After the reaction is completed, filtering, washing and drying are performed to obtain the modified adsorbent.

[0075] In this embodiment, the purity of the industrial-grade methyldiethoxysilane raw material is 93.3%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.93%.

[0076] Example 4

[0077] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0078] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.12 MPa, the tower top temperature is 106° C., the tower bottom pressure is 0.1 MPa, and the tower bottom temperature is 130° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 70, the tower top pressure is 0.11 MPa, and the tower top temperature is 103° C.; the tower bottom pressure is 0.1 MPa, and the tower bottom temperature is 110° C., and a distillation treatment product is obtained;

[0079] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 60° C., and after adsorption for 1 hour, an adsorption product is obtained;

[0080] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 50, the tower top pressure is 0.12 MPa, the tower top temperature is 106°C, the tower bottom pressure is 0.1 MPa, and the tower bottom temperature is 130°C. The obtained product is introduced into a condenser from the tower top and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 70, the tower top pressure is 0.11 MPa, and the tower top temperature is 103°C; the tower bottom pressure is 0.1 MPa, and the tower bottom temperature is 110°C, thereby obtaining the electronic grade methyldiethoxysilane;

[0081] Wherein, the adsorption tank is filled with a modified adsorbent;

[0082] The preparation method of the modified adsorbent comprises the following steps:

[0083] S1, 100g activated carbon powder was added to 800mL acidic manganese permanganate solution (the concentration of potassium permanganate was 50g / L, and the pH was 2), and the mixture was immersed in the solution for 2h at 50°C. After the treatment, the mixture was filtered and dried, and then calcined in an ammonia atmosphere at a temperature of 700°C for 1h. After the calcination, pretreated activated carbon was obtained;

[0084] S2, adding 100g of pretreated activated carbon in step S1 to 1L of dimethylformamide, then adding 20g of 2,5-thiophenedicarboxylic acid, 24g of 2-mercapto-6-chlorobenzothiazole, and 40g of triethylamine, stirring and reacting at 80°C for 2h, filtering, washing, and drying after the reaction is completed to obtain modified activated carbon;

[0085] S3, adding 10g of chitosan to 1000g of acetic acid solution with a mass concentration of 10%, stirring to dissolve, to obtain a chitosan solution, then adding 90g of the modified activated carbon in step S2, and reacting at 90°C for 7h under a nitrogen atmosphere. During the reaction, adding a 5% NaOH solution every 1h to adjust the pH to 9. After the reaction is completed, filtering, washing and drying are performed to obtain the modified adsorbent.

[0086] In this embodiment, the purity of the industrial-grade methyldiethoxysilane raw material is 93.8%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.98%.

[0087] Comparative Example 1

[0088] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0089] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 50, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.09 MPa, and the tower top temperature is 99° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., and a distillation treatment product is obtained;

[0090] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 55° C., and after adsorption for 1.5 hours, an adsorption product is obtained;

[0091] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 45, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., and the obtained product is introduced into a condenser from the tower top, and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 65, the tower top pressure is 0.1 MPa, and the tower top temperature is 98° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., thereby obtaining the electronic grade methyldiethoxysilane;

[0092] Wherein, the adsorption tank is filled with a modified adsorbent;

[0093] The preparation method of the modified adsorbent comprises the following steps:

[0094] S1, 100g activated carbon powder was added to 800mL acidic manganese permanganate solution (potassium permanganate concentration is 40g / L, pH is 1.5), and immersed at 45°C for 2.5h. After the treatment, it was filtered and dried, and then calcined in an ammonia atmosphere at a temperature of 50°C for 1.5h. After the calcination, pretreated activated carbon was obtained;

[0095] S2. Add 8 g of chitosan to 900 g of 10% acetic acid solution, stir and dissolve to obtain a chitosan solution, then add 80 g of pretreated activated carbon in step S1, and react at 85°C for 9 h under a nitrogen atmosphere. During the reaction, add 5% NaOH solution every 1 h to adjust the pH to 8.5. After the reaction is completed, filter, wash and dry to obtain the modified adsorbent.

[0096] In this comparative example, the purity of the industrial-grade methyldiethoxysilane raw material is 92.8%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.56%.

[0097] Comparative Example 2

[0098] A method for preparing electronic grade methyldiethoxysilane comprises the following steps:

[0099] (a) adding industrial-grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, the theoretical plate number of the distillation tower is 50, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., the obtained product is introduced into a condenser from the tower top, and then enters a second distillation tower, performing a de-light treatment, the theoretical plate number of the distillation tower is 60, the tower top pressure is 0.09 MPa, and the tower top temperature is 99° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., and a distillation treatment product is obtained;

[0100] (b) introducing the distillation product in step (a) into an adsorption tank for impurity adsorption, the temperature of the adsorption tank is 55° C., and after adsorption for 1.5 hours, an adsorption product is obtained;

[0101] (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and de-heavy treatment, wherein the theoretical plate number of the distillation tower is 45, the tower top pressure is 0.1 MPa, the tower top temperature is 105° C., the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 125° C., and the obtained product is introduced into a condenser from the tower top, and then enters a fourth distillation tower for secondary de-light treatment, wherein the theoretical plate number of the distillation tower is 65, the tower top pressure is 0.1 MPa, and the tower top temperature is 98° C.; the tower bottom pressure is 0.08 MPa, and the tower bottom temperature is 108° C., thereby obtaining the electronic grade methyldiethoxysilane;

[0102] Wherein, the adsorption tank is filled with a modified adsorbent;

[0103] The preparation method of the modified adsorbent comprises the following steps:

[0104] 100 g of activated carbon was added to 1 L of dimethylformamide, followed by 15 g of 2,5-thiophenedicarboxylic acid, 18 g of 2-mercapto-6-chlorobenzothiazole and 35 g of triethylamine. The mixture was stirred at 75° C. for 3 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a modified adsorbent.

[0105] In this comparative example, the purity of the industrial-grade methyldiethoxysilane raw material is 93.2%, and the purity of the obtained electronic-grade methyldiethoxysilane is 99.41%.

[0106] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing electronic grade methyldiethoxysilane, characterized in that: The following steps are involved: (a) adding industrial grade methyldiethoxysilane to a first distillation tower, performing a distillation and de-heavy treatment, and introducing the obtained product into a condenser from the tower top, and then entering a second distillation tower, performing a de-light treatment, and obtaining a distillation product; (b) introducing the distillation product in step (a) into an adsorption tank to adsorb impurities, and after the adsorption is completed, an adsorption product is obtained; (c) introducing the adsorption treatment product in step (b) into a third distillation tower for secondary distillation and heavy removal treatment, and introducing the obtained product into a condenser from the top of the tower, and then entering a fourth distillation tower for secondary light removal treatment to obtain the electronic grade methyldiethoxysilane; Wherein, the adsorption tank is filled with modified adsorbent.

2. The preparation method according to claim 1, characterized in that: In step (a), the number of theoretical plates of the first distillation tower is 30-60, the top pressure is 0.08-0.12 MPa, the top temperature is 102-106°C, the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 120-130°C; the number of theoretical plates of the second distillation tower is 50-70, the top pressure is 0.06-0.11 MPa, and the top temperature is 98-103°C; the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 105-110°C.

3. The preparation method according to claim 1, characterized in that: The temperature of the adsorption tank in step (b) is 50-60° C., and the adsorption time is 1-2 hours.

4. The preparation method according to claim 1, characterized in that: The third distillation tower in step (c) has a theoretical plate number of 40-50, a top pressure of 0.08-0.12 MPa, a top temperature of 102-106°C, a bottom pressure of 0.05-0.1 MPa, and a bottom temperature of 120-130°C; the fourth distillation tower has a theoretical plate number of 60-70, a top pressure of 0.06-0.11 MPa, and a top temperature of 98-103°C; the bottom pressure is 0.05-0.1 MPa, and the bottom temperature is 105-110°C.

5. The preparation method according to claim 1, characterized in that: The preparation method of the modified adsorbent comprises the following steps: S1, adding activated carbon powder to an acidic manganese permanganate solution for impregnation treatment, filtering and drying after the treatment, and then roasting in an ammonia atmosphere, and obtaining pretreated activated carbon after the roasting; S2, adding the pretreated activated carbon in step S1 to dimethylformamide, and then adding 2,5-thiophenedicarboxylic acid, 2-mercapto-6-chlorobenzothiazole, and triethylamine, stirring to react, and filtering, washing, and drying after the reaction is completed to obtain modified activated carbon; S3, adding chitosan to the acetic acid solution, stirring and dissolving to obtain a chitosan solution, then adding the modified activated carbon in step S2, and reacting at a constant temperature under a nitrogen atmosphere, controlling the pH value between 8 and 9 during the reaction, filtering, washing and drying after the reaction is completed to obtain the modified adsorbent.

6. The preparation method according to claim 5, characterized in that: In step S1, the concentration of potassium permanganate in the acidic potassium permanganate solution is 30-50 g / L, and the pH is 1-2; the immersion temperature is 40-50° C., and the time is 2-3 h; the calcination temperature is 600-700° C., and the time is 1-2 h.

7. The preparation method according to claim 5, characterized in that: The mass ratio of the pretreated activated carbon, 2,5-thiophenedicarboxylic acid, 2-mercapto-6-chlorobenzothiazole and triethylamine in step S2 is 100:10-20:12-24:30-40.

8. The preparation method according to claim 5, characterized in that: The stirring reaction in step S2 is carried out at a temperature of 70-80° C. and for a time of 2-4 hours.

9. The preparation method according to claim 5, characterized in that: The mass concentration of the acetic acid solution in step S3 is 5-10%, and the mass ratio of the chitosan, acetic acid solution and modified activated carbon is 5-10:800-1000:70-90; the temperature of the isothermal reaction is 80-90°C and the time is 7-10h.

10. The preparation method according to claim 5, characterized in that: The specific steps of controlling the pH in step S3 are: adding a 5% by mass NaOH solution to adjust the pH to 8-9 every 1 hour of reaction.