Silicon powder supported catalyst and its use for increasing the content of dichlorodihydrogen silicon

Abstract

The application provides a silicon powder supported catalyst and application thereof in increasing the content of dichlorodihydrogen silicon. The preparation method of the silicon powder supported catalyst comprises the following steps: S1, preparing polyether modified silane through a silicon hydrogen addition reaction of allyl polyethylene glycol monomethyl ether and hydrogen-containing trimethoxysilane under the action of a catalyst; S2, mixing an aqueous solution of the polyether modified silane obtained in step S1 with an aqueous solution of nitrate, adding silicon powder, treating at 50-60 DEG C for 1-3 h, filtering to obtain solid, and calcining at 200-400 DEG C to obtain the silicon powder supported catalyst. The silicon powder supported catalyst prepared by the method can effectively realize the synthesis of trichlorosilane and increase the synthesis proportion of dichlorodihydrogen silicon, the method has low cost, and the content of the obtained dichlorodihydrogen silicon is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst synthesis, more particularly, to a silicon powder supported catalyst and its application in improving the content of dichlorodihydrogen silicon. BACKGROUND

[0002] The application prospect of dichlorodihydrogen silicon as a silicon source gas in semiconductor epitaxy and chemical vapor deposition processes is being continuously explored. In the existing technology, anion exchange resin or organic amine catalyst is mostly used in the polysilicon and organosilicon industry to catalyze the disulfuration of trichlorosilane to prepare silicon tetrachloride, and dichlorodihydrogen silicon is obtained at the same time, but in this method, the resin and catalyst need to be pre-treated to remove water, the cost of tower installation is high, and the resin replacement cycle is 4-6 months, which has high processing cost. At the same time, in the existing technology, for example, CN201210047067.1, trichlorosilane is used to prepare dichlorodihydrogen silicon under the action of a catalyst, which has high cost and low conversion rate. In the synthesis reaction of organosilicon monomer trichlorosilane, the by-product dichlorodihydrogen silicon accounts for about 0.2-0.4wt% of the trichlorosilane output. Since part of the dichlorodihydrogen silicon (dichlorodihydrogen silicon is unstable) is converted into silicon tetrachloride and other multi-chlorosilicon compounds during distillation and purification, the actual output of dichlorodihydrogen silicon is about 0.08wt%. SUMMARY

[0003] The first object of the present application is to provide a preparation method of a silicon powder supported catalyst, which can economically and effectively achieve the synthesis of trichlorosilane while improving the synthesis ratio of dichlorodihydrogen silicon.

[0004] The preparation method of the silicon powder supported catalyst provided by the present application comprises the following steps:

[0005] S1, preparing a polyether modified silane by a hydrosilylation reaction of allyl polyethylene glycol monomethyl ether and hydrogen-containing trimethoxysilane under the action of a catalyst;

[0006] S2, mixing the aqueous solution of the polyether modified silane obtained in step S1 with an aqueous solution of a nitrate, adding silicon powder, treating at 50-60℃ for 1-3h, filtering to obtain the solid, and calcining at 200-400℃ to obtain the silicon powder supported catalyst.

[0007] In the specific embodiment of the present application, in step S1, the polyethylene glycol monomethyl ether in the allyl polyethylene glycol monomethyl ether can be ethylene glycol monomethyl ether, MPEG350, MPEG550, MPEG750, MPEG1000, etc., and is preferably MPEG350. In step S1, the allyl polyethylene glycol monomethyl ether can be purchased or self-made. In one specific embodiment of the present application, the preparation method of the allyl polyethylene glycol monomethyl ether can comprise the following steps: after the polyethylene glycol monomethyl ether is subjected to a sodium alkoxide alkylation reaction, it is filtered, and chloropropene is added dropwise to obtain. In the preparation method, the polyethylene glycol monomethyl ether can be ethylene glycol monomethyl ether, MPEG350, MPEG550, MPEG750, MPEG1000, etc., and is preferably MPEG350. Among them, the sodium alkoxide can be sodium methoxide, etc. In order to improve the catalytic effect of the obtained catalyst, the molar ratio of the polyethylene glycol monomethyl ether to the sodium alkoxide is preferably 1:(1.05-1.1). The molar ratio of the polyethylene glycol monomethyl ether to the chloropropene is preferably 1:(1.2-1.4).

[0008] In one preferred embodiment of the present application, the preparation method of the allyl polyethylene glycol monomethyl ether preferably comprises the following steps: the polyethylene glycol monomethyl ether and sodium methoxide are mixed according to the ratio, and are subjected to a reaction under reduced pressure at 100-120°C while removing low-boiling substances under reduced pressure until no bubbles are generated, and are cooled to 40-50°C under nitrogen protection, chloropropene is added dropwise to the system, the temperature of the system is maintained at not more than 60°C, the dropwise addition time is 1-2h, the system is maintained for 1-2h, the system is neutralized to pH 4.5-6.5, and vacuum distillation and filtration are performed to obtain. The system can be neutralized to pH 4.5-6.5 by using a neutralizing agent commonly used in the art, for example, the neutralizing agent can be hydrochloric acid, acetic acid, etc.

[0009] In one preferred embodiment of the present application, in order to improve the catalytic effect of the obtained catalyst, in step S1, the molar ratio of the allyl polyethylene glycol monomethyl ether to the hydrogen-containing trimethoxysilane is 1:(1-1.2).

[0010] In one preferred embodiment of the present application, in order to improve the catalytic effect of the obtained catalyst, in step S1, the catalyst is isopropyl alcohol solution of chloroplatinic acid. The concentration of the isopropyl alcohol solution of chloroplatinic acid is conventionally selected, for example, it can be 5wt%. The amount of the catalyst is preferably such that the content of Pt in the system is 10-50ppm.

[0011] In a preferred embodiment of the present application, in step S1, the reaction temperature of the hydrosilylation reaction is 80-90°C, and the reaction time is 3-4h. In a specific embodiment of the present application, the raw material allyl polyethylene glycol monomethyl ether and hydrogen-containing trimethoxysilane of step S1 can be activated as needed. The specific activation steps can include: under nitrogen protection, the catalyst is activated with allyl polyethylene glycol monomethyl ether at 80-85°C for 1h, and then hydrogen-containing trimethoxysilane is added dropwise for hydrosilylation reaction.

[0012] In a preferred embodiment of the present application, in step S2, the polyether-modified silane obtained in step S1 can be dissolved in water to obtain a polyether-modified silane aqueous solution, and the mass concentration of the aqueous solution is preferably 5-10wt%. In the present application, the polyether-modified silane aqueous solution is obtained by dissolving the polyether-modified silane in water at room temperature.

[0013] In a preferred embodiment of the present application, in step S2, the nitrate aqueous solution can be copper nitrate or a nitrate aqueous solution. The concentration of the nitrate aqueous solution is preferably 0.1-0.5mol / L. In a preferred embodiment of the present application, in order to improve the catalytic effect of the obtained catalyst, the amount of the nitrate aqueous solution used in step S2 is 10-20wt% of the mass of the polyether-modified silane.

[0014] In a specific embodiment of the present application, the silicon powder can use a silicon powder raw material for synthesizing trichlorosilane. In a preferred embodiment of the present application, in order to improve the catalytic effect of the obtained catalyst, the amount of the silicon powder added in step S2 is 3-6 times the mass of the polyether-modified silane.

[0015] In a preferred embodiment of the present application, in order to improve the catalytic effect of the obtained catalyst, the specific steps of calcination in step S2 include: starting from 250°C, increasing the temperature at a rate of 1-5°C / min, increasing to 250-300°C and maintaining for 10-20min, increasing to 300-350°C and maintaining for 10-20min, and increasing to 350-400°C and maintaining for 30-60min. In a preferred embodiment of the present application, the specific steps preferably include: starting from 250°C, increasing the temperature at a rate of 1-5°C / min, increasing to 250-300°C and maintaining for 10-20min, increasing to 300-350°C and maintaining for 10-20min at a rate of 1-5°C / min, and increasing to 350-400°C and maintaining for 30-60min at a rate of 3-8°C / min.

[0016] The silicon powder supported catalyst obtained by the preparation method provided by the present application can catalyze the reaction of silicon powder and hydrogen chloride, and the content of dichlorodihydrogen silicon in the obtained product is at least 1 wt%, preferably at least 1.5 wt%, and the obtained dichlorodihydrogen silicon accounts for not less than 1.5 wt% of trichlorohydrogen silicon, preferably not less than 2 wt%, effectively improving the synthesis ratio of dichlorodihydrogen silicon in trichlorohydrogen silicon.

[0017] That is, another object of the present application is to provide the silicon powder supported catalyst obtained by the above preparation method.

[0018] Still another object of the present application is to provide the application of the silicon powder supported catalyst obtained by the above preparation method in the synthesis of trichlorohydrogen silicon.

[0019] In a preferred embodiment of the present application, the step of synthesizing trichlorohydrogen silicon comprises: pre-mixing the silicon powder supported catalyst and silicon powder at 220-240°C, and then introducing hydrogen chloride gas, and reacting at 350-370°C and 0.09-0.1 MPa.

[0020] Preferably, the silicon powder supported catalyst is 1-5 wt% of the mass of the silicon powder. Preferably, 1 kg of silicon powder corresponds to 2.8-3.0 m 3 .

[0021] In the synthesis reaction, the reaction is carried out at 350-370°C and 0.09-0.1 MPa (the reaction of silicon powder and hydrogen chloride is an instantaneous exothermic reaction, and usually the reaction can be 10-30 min for sufficient reaction), and after the reaction is completed, the obtained gas phase crude product is usually first passed through a cyclone dust collector and then a bag filter to remove a small amount of unreacted silicon powder, and then the crude trichlorohydrogen silicon obtained in the previous batch is used as a spray liquid (if it is the first batch, trichlorohydrogen silicon with a trichlorohydrogen silicon content of 99.5% and a dichlorodihydrogen silicon content of 0.12% can be used as the spray liquid), and wet dust removal is carried out by using a wet dust collector to obtain the crude trichlorohydrogen silicon.

[0022] The silicon powder supported catalyst obtained by the preparation method provided by the present application can effectively realize the synthesis of trichlorohydrogen silicon while improving the synthesis ratio of dichlorodihydrogen silicon, the method has low cost and high content of dichlorodihydrogen silicon. At the same time, the catalyst provided by the present application is suitable for other disproportionation reactions and reactions requiring control of metal ions, and has wide applicability. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application will be further described in detail below in conjunction with examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0024] In the present application, unless otherwise specified, "%" represents mass percentage.

[0025] Example 1

[0026] 1. Synthesis of polyether-modified silane

[0027] Into a three-necked flask was added 700 g of MPEG350 and 116.6 g of solid sodium methoxide, and low-boiling substances were distilled off under negative pressure while slowly raising the temperature. The temperature was slowly raised to 118°C without bubbling, and 196 g of chloropropene was added dropwise at 42°C under nitrogen protection, with the temperature of the dropwise addition not exceeding 58°C. The dropwise addition took 1 h, and the reaction was maintained for 1.5 h. A 10% aqueous hydrochloric acid solution was added to neutralize the mixture to a pH of 6.2, and low-boiling substances were removed under vacuum and filtered. Then, 264 g of a solution of hydrogen-containing trimethoxysilane and 5% chloroplatinic acid in isopropyl alcohol was added (the amount of the solution of chloroplatinic acid in isopropyl alcohol was such that the Pt content in the system was 15-20 ppm), and the mixture was reacted at 82-85°C for 4 h. The temperature was lowered, and low-boiling substances were distilled off until no bubbling occurred. A total of 992.3 g of a light yellow transparent polyether-modified silane was obtained, with a solid content of 9.62%, an iodine value of 11.6%, and a methanol content of 0.092% as determined by GC internal standard testing, a hydrogen-containing trimethoxysilane content of 0.11%, and a tetramethoxysilane content of 0.29%.

[0028] 2. Preparation of a silicon powder supported catalyst

[0029] 60 g of the polyether-modified silane was added to 700 g of tap water, and the mixture was stirred at room temperature to obtain a uniform aqueous solution. 7 g of a 0.26 mol / L aqueous silver nitrate solution was added, and the mixture was stirred thoroughly. 270 g of silicon powder was added, and the mixture was heated at 52-54°C for 100 min. The solid was then filtered, and the obtained solid was placed in a crucible. The temperature was raised to 250°C, and then raised to 280°C at a rate of 2°C / min, and maintained at 280°C for 10 min. Then, the temperature was raised to 350°C at a rate of 2°C / min, and maintained at 350°C for 15 min. Finally, the temperature was raised to 370°C at a rate of 5°C / min, and maintained at 370°C for 40 min. The temperature was then lowered, and 105.3 g of a silicon powder supported catalyst was obtained.

[0030] 3. Synthesis of trichlorosilane

[0031] The obtained 80 g of the silicon powder supported catalyst was mixed with 3000 g of silicon powder in a pre-mixing furnace at 220-240°C for 20 min, and then transferred to a synthesis furnace. The synthesis furnace was continuously supplied with 8.7 m 3After the reaction for 10 min under the conditions of maintaining the temperature in the furnace at 350-370°C and the pressure at 0.09-0.1 MPa, the synthesized gas-phase crude product is first subjected to a cyclone dust collector and a bag filter to remove a small amount of unreacted silicon powder, and then subjected to wet dust removal using trichlorosilane with a trichlorosilane content of 99.5% and a dichlorodisilane content of 0.12% as a spray liquid (in the actual process, the trichlorosilane crude product obtained in the previous batch is used as the spray liquid), to obtain trichlorosilane crude product. The GC content of the trichlorosilane crude product is tested to be: air 0.014%, hydrogen chloride 0.027%, dichlorodisilane 1.61%, trichlorosilane 76.832%, silicon tetrachloride 20.75%, hexachlorodisilane 0.437%, and octachlorotrisilane 0.276%.

[0032] Example 2

[0033] The method provided in this example is the same as the method provided in Example 1, except that 1, the synthesis of the polyether-modified silane:

[0034] 1. Synthesis of polyether-modified silane

[0035] In a three-necked flask, 152.2 g of ethylene glycol monomethyl ether and 113.5 g of solid sodium methoxide were added, and low-boiling substances were distilled off under negative pressure while slowly increasing the temperature. The temperature was slowly increased to 115°C without bubbling, and 184 g of chloropropene was added dropwise at 45°C under nitrogen protection, with the temperature during dropwise addition being maintained at no more than 58°C. The dropwise addition took 1 h, and the reaction was maintained for 2 h. A 10% concentration of hydrochloric acid aqueous solution was added for neutralization to a pH of 6.0, and filtration was performed under vacuum to obtain the product. Then, 264 g of hydrogen-containing trimethylsilane and 5 wt% of chloroplatinic acid isopropyl alcohol solution (the amount of chloroplatinic acid isopropyl alcohol solution added was such that the Pt content in the system was 15-20 ppm) were added, and the reaction was performed at 82-85°C for 3 h. Distillation was performed to remove low-boiling substances until no bubbles were generated, to obtain 451.3 g of light yellow transparent polyether-modified silane. The solid content of the obtained product was 25.83%, the iodine value was 0.18%, and the GC internal standard test results were as follows: methanol 0.08%, hydrogen-containing trimethylsilane 0.12%, and tetramethoxysilane 0.19%.

[0036] The trichlorosilane crude product obtained using the silicon powder supported catalyst obtained in this example was synthesized using the method of “3, synthesis of trichlorosilane” in Example 1. The GC content of the trichlorosilane crude product was tested to be: air 0.016%, hydrogen chloride 0.027%, dichlorodisilane 1.48%, trichlorosilane 77.03%, silicon tetrachloride 20.77%, hexachlorodisilane 0.453%, and octachlorotrisilane 0.175%.

[0037] Example 3

[0038] The method provided in this example is the same as the method provided in Example 1, except that: 2, preparation of the silicon powder supported catalyst:

[0039] 2, preparation of the silicon powder supported catalyst

[0040] 60 g of polyether modified silane was added to 1140 g of tap water, stirred at room temperature to obtain a uniform aqueous solution, 11.4 g of 0.5 mol / L silver nitrate aqueous solution was added and stirred thoroughly, 300 g of silicon powder was added and heated at 52-54℃ for 100 min, then the solid was filtered, the obtained solid was placed in a crucible, the temperature was raised to 250℃ at a rate of 2℃ / min, kept for 10 min, then the temperature was raised to 350℃ at a rate of 2℃ / min, kept for 15 min, finally the temperature was raised to 370℃ at a rate of 5℃ / min, kept for 40 min, and then the temperature was lowered to obtain the silicon powder supported catalyst.

[0041] The crude trichlorosilane obtained by using the silicon powder supported catalyst obtained in this example and the method of "3, synthesis of trichlorosilane" in Example 1 was used for testing. The GC content of the crude trichlorosilane was: air 0.016%, hydrogen chloride 0.028%, dichlorodihydrogen silane 1.56%, trichlorosilane 76.73%, silicon tetrachloride 20.84%, hexachlorodisilane 0.452%, octachlorotrisilane 0.183%.

[0042] Example 4

[0043] The method provided in this example is the same as the method provided in Example 1, except that: 2, preparation of the silicon powder supported catalyst:

[0044] 2, preparation of the silicon powder supported catalyst

[0045] 60 g of polyether modified silane was added to 1140 g of tap water, stirred at room temperature to obtain a uniform aqueous solution, 11.4 g of 0.5 mol / L silver nitrate aqueous solution was added and stirred thoroughly, 300 g of silicon powder was added and heated at 52-54℃ for 100 min, then the solid was filtered, the obtained solid was placed in a crucible, the temperature was raised to 250℃ at a rate of 2℃ / min, kept for 10 min, then the temperature was raised to 350℃ at a rate of 2℃ / min, kept for 15 min, finally the temperature was raised to 370℃ at a rate of 5℃ / min, kept for 40 min, and then the temperature was lowered to obtain the silicon powder supported catalyst.

[0046] The crude trichlorosilane obtained by using the silicon powder supported catalyst obtained in this example and the method of "3, synthesis of trichlorosilane" in Example 1 was used for testing. The GC content of the crude trichlorosilane was: air 0.016%, hydrogen chloride 0.028%, dichlorodihydrogen silane 1.56%, trichlorosilane 76.73%, silicon tetrachloride 20.84%, hexachlorodisilane 0.452%, octachlorotrisilane 0.183%.

[0047] Finally, the method of the present application is only a preferred embodiment, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a silicon powder supported catalyst, comprising the following steps: S1, polyether-modified silane is prepared by hydrosilylation reaction of allyl polyethylene glycol monomethyl ether and hydrogen-containing trimethoxysilane under the action of a catalyst; S2, after mixing the aqueous solution of polyether-modified silane obtained in step S1 with the aqueous solution of nitrate, add silicon powder, treat at 50-60℃ for 1-3 hours, filter to obtain the solid, and calcine at 200-400℃ to obtain the product; The nitrate aqueous solution is either a copper nitrate aqueous solution or a silver nitrate aqueous solution.

2. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of allyl polyethylene glycol monomethyl ether to hydrogen-containing trimethoxysilane is 1:(1-1.2).

3. The preparation method according to claim 1 or 2, characterized in that, In step S1, the catalyst is an isopropanol chloroplatinic acid solution, and the amount of catalyst used is such that the Pt content in the system is 10-50 ppm.

4. The preparation method according to claim 1 or 2, characterized in that, In step S1, the reaction temperature of the hydrosilylation reaction is 80-90°C, and the reaction time is 3-4 hours.

5. The preparation method according to claim 1 or 2, characterized in that, In step S2, the nitrate aqueous solution is 10-20 wt% of the polyether-modified silane, the concentration of the polyether-modified silane aqueous solution is 5-10 wt%, and the concentration of the nitrate aqueous solution is 0.1-0.5 mol / L.

6. The preparation method according to claim 1 or 2, characterized in that, In step S2, the amount of silicon powder added is 3 to 6 times the mass of the polyether-modified silane.

7. The preparation method according to claim 1 or 2, characterized in that, In step S2, the specific steps of calcination include: starting from 250°C, increasing the temperature at a rate of 1 to 5°C / min, raising it to 250 to 300°C and holding it for 10 to 20 minutes, raising it to 300 to 350°C and holding it for 10 to 20 minutes, raising it to 350 to 400°C and holding it for 30 to 60 minutes.

8. The silicon powder supported catalyst obtained by the preparation method according to any one of claims 1 to 7.

9. The application of the silicon powder supported catalyst according to claim 8 in the synthesis of trichlorosilane.

10. The application according to claim 9, characterized in that, The silicon powder supported catalyst is premixed with silicon powder at 220–240°C, and then hydrogen chloride gas is introduced, and the reaction is carried out at 350–370°C and 0.09–0.1 MPa.