Preparation method of monosilane

Abstract

The invention relates to a monosilane preparation method, which comprises: carrying out a contact reaction on silicon tetrafluoride and a solid alkali solution, carrying out filtration separation on the reaction material, and carrying out first rectification treatment on the liquid phase product to obtain a first intermediate product; carrying out hydrotreatment on the first intermediate product, and carrying out second rectification treatment on a reaction product to obtain a second intermediate product; and carrying out disproportionation reaction on the second intermediate product, and carrying out third rectification treatment on the reaction product to obtain monosilane. According to the preparation method provided by the invention, silicon tetrafluoride is used as a silicon source, so that the raw material cost is reduced; although rectification treatment is involved, the boiling point of a product is relatively higher, the purification difficulty is small, the energy consumption is lower, rectification of halogen-containing substances is not involved, a rectification device does not need to consider the corrosion problem, and the device investment is reduced; a byproduct is only villiaumite of alkali metal, and the application field is wide; moreover, in the preparation method, all the raw materials can be recycled, and the overall cost advantage is more obvious.

Description

Technical Field

[0001] The present invention belongs to the technical field of silane production, and relates to a method for preparing silane, in particular to a method for preparing silane. Background Art

[0002] Silane is an important gas source for providing silicon components and is widely used in technical fields such as photovoltaic solar energy, automobiles, construction, flat panel displays, semiconductors, and IC manufacturing. At present, the preparation methods of silane include the magnesium-silicon method, the lithium-silicon method, the fluorosilicon method, and the chlorosilicon method. Among them, the magnesium-silicon method and the chlorosilicon method are not used in large-scale production due to cost problems. Therefore, the mainstream industrial production methods are the fluorosilicon method and the chlorosilicon method.

[0003] The raw materials of the chlorosilicon method (REC method) are easily available, and the by-product tetrachlorosilane can be recycled. The reaction equation is as follows:

[0004] 4SiHCl3→SiH4+3SiCl4

[0005] 3SiCl4+Si+2H2→4SiHCl3

[0006] The REC method forms a closed-loop production process similar to the direct hydrogenation of metallurgical silicon to prepare silane, and the disproportionation conversion rate of SiHCl3 is increased to more than 95%, greatly improving the industrial conversion value. However, the disproportionation of this scheme needs to improve the conversion rate by means of reactive distillation, with high process energy consumption, and the treatment efficiency of the by-product SiCl4 is slightly insufficient.

[0007] The fluorosilicon method (MEMC method) uses aluminum powder, liquid metal sodium and hydrogen to react to prepare sodium aluminum hydride, and then uses sodium aluminum hydride to reduce silicon tetrafluoride to prepare silane, while obtaining sodium aluminum fluoride. The reaction equation is as follows:

[0008] Na+Al+2H2→NaAlH4

[0009] NaAlH4+SiF4→SiH4+NaAlF4

[0010] The process conversion rate of the MEMC method is high, and the synthesis process does not require auxiliary operations such as rectification, with low energy consumption. However, this method has a high dependence on raw materials, and the resource treatment of the by-product NaAlF4 needs to be considered.

[0011] Therefore, the commonly used REC method and MEMC method in the prior art have their respective technical problems. Therefore, it is necessary to provide a method for preparing silane with low cost and high safety. Summary of the Invention

[0012] In view of the deficiencies of the existing technologies, the purpose of the present invention is to provide a method for preparing silane. The preparation method can overcome the defects of the REC method and the MEMC method, uses silicon tetrafluoride as a silicon source, and reduces the raw material cost; although it involves rectification treatment, the boiling point of the product is relatively higher, the purification difficulty is small, the energy consumption is lower, and it does not involve the rectification of halogen-containing substances. The rectification device does not need to consider corrosion problems, reducing the device investment; the by-product is only the fluoride salt of an alkali metal, and it has a wide range of application fields; moreover, in the preparation method of the present invention, each raw material can be recycled, and the overall cost advantage is more obvious.

[0013] To achieve the purpose of this invention, the following technical solutions are adopted:

[0014] The present invention provides a method for preparing silane, and the preparation method includes the following steps:

[0015] (1) Silicon tetrafluoride is contacted and reacted with a solid base solution, the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment to obtain a first intermediate product;

[0016] (2) The first intermediate product is subjected to a hydrogenation treatment, and the reaction product is subjected to a second rectification treatment to obtain a second intermediate product;

[0017] (3) The second intermediate product is subjected to a disproportionation reaction, and the reaction product is subjected to a third rectification treatment to obtain silane.

[0018] In each step of the preparation method provided by the present invention, the involved reaction equations are as follows:

[0019] SiF4 + 4ROA → Si(RO)4 + 4AF;

[0020] Si(RO)4 + H2 → SiH x (RO) y + H2O;

[0021] SiH x (RO) y → SiH4 + Si(RO)4;

[0022] Wherein ROA represents a solid base, A is an alkali metal, R is an organic group, x is 1 - 3, and x + y = 4.

[0023] The preparation method provided by the present invention uses silicon tetrafluoride as a silicon source, reducing the raw material cost; although it involves rectification treatment, the boiling point of the product is relatively higher, the purification difficulty is small, the energy consumption is lower, and it does not involve the rectification of halogen-containing substances. The rectification device does not need to consider corrosion problems, reducing the device investment; the by-product is only the fluoride salt of an alkali metal, and it has a wide range of application fields; moreover, in the preparation method of the present invention, each raw material can be recycled, and the overall cost advantage is more obvious.

[0024] The present invention separates the volume in the reaction system from the product by the first rectification treatment; separates the unreacted raw materials from the hydrogenation-treated product by the second rectification treatment; and separates silane from the reaction system by the third rectification treatment.

[0025] Preferably, the gauge pressure of the first rectification treatment is from -0.09 MPa to 0 MPa, for example, it can be -0.09 MPa, -0.08 MPa, -0.06 MPa, -0.05 MPa, -0.03 MPa or 0 MPa, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.

[0026] Preferably, the temperature of the first rectification treatment is 20°C - 120°C, for example, it can be 20°C, 40°C, 50°C, 60°C, 80°C, 100°C or 120°C, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.

[0027] Preferably, the gauge pressure of the second rectification treatment is from -0.09 MPa to 0 MPa, for example, it can be -0.09 MPa, -0.08 MPa, -0.06 MPa, -0.05 MPa, -0.03 MPa or 0 MPa, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.

[0028] Preferably, the temperature of the second rectification treatment is 50°C - 120°C, for example, it can be 50°C, 60°C, 80°C, 100°C or 120°C, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.

[0029] Preferably, the third rectification treatment is carried out under normal pressure conditions.

[0030] Preferably, the temperature of the third rectification treatment is from -60°C to 50°C, for example, it can be -60°C, -50°C, -30°C, 0°C, 20°C, 30°C or 50°C, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.

[0031] Preferably, the contact reaction in step (1) includes: injecting a solid base solution into a sealed container under a protective atmosphere, then bringing the temperature and pressure to the reaction requirements, and introducing silicon tetrafluoride gas under stirring conditions; after the introduction of silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure in the sealed container are reduced to the end temperature (-80°C to 100°C, preferably 0°C - 50°C) and normal pressure (gauge pressure 0 MPa).

[0032] During the reaction in step (1), the purpose of stirring is to ensure the full reaction of the solid base with silicon tetrafluoride. The present invention does not specifically limit the stirring speed, as long as the purpose of stirring can be achieved.

[0033] Preferably, the solid base in the solid base solution includes any one or a combination of at least two of sodium methoxide, sodium ethoxide, sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide, or potassium tert-butoxide. Typical but non-limiting combinations include the combination of sodium methoxide and sodium ethoxide, the combination of sodium n-propoxide and sodium isopropoxide, the combination of sodium n-butoxide, sodium isobutoxide, and sodium tert-butoxide, the combination of potassium methoxide and potassium ethoxide, the combination of potassium n-propoxide and potassium isopropoxide, the combination of potassium n-butoxide, potassium isobutoxide, and potassium tert-butoxide, or the combination of sodium methoxide, sodium ethoxide, sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide, and potassium tert-butoxide.

[0034] Preferably, the solid base in the solid base solution includes any one or a combination of at least two of sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide, or potassium tert-butoxide. Typical but non-limiting combinations include the combination of sodium n-propoxide and sodium isopropoxide, the combination of sodium n-butoxide, sodium isobutoxide, and sodium tert-butoxide, the combination of potassium n-propoxide and potassium isopropoxide, the combination of potassium n-butoxide, potassium isobutoxide, and potassium tert-butoxide, or the combination of sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide, and potassium tert-butoxide.

[0035] Preferably, the solvent in the solid base solution includes any one or a combination of at least two of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), or N,N-dimethylformamide (DMF). Typical but non-limiting combinations include the combination of methanol and ethanol, the combination of n-propanol and isopropanol, the combination of n-butanol, isobutanol, and tert-butanol, the combination of DMSO, THF, and DMF, or the combination of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, DMSO, THF, and DMF.

[0036] The temperature of the reaction in step (1) affects the conversion rate and the yield. If the reaction temperature is too low, the reaction rate will decrease and the reaction will not be completely converted, forming an intermediate product similar to SiF x (OR) y which will affect the subsequent reaction; if the reaction temperature is too high, the product will decompose, affecting the yield of the reaction.

[0037] Preferably, the temperature of the reaction in step (1) is 30°C - 200°C. For example, it can be 30°C, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C, 150°C, 160°C, 180°C or 200°C, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable, and preferably it is 30°C - 120°C.

[0038] Preferably, the gauge pressure of the reaction in step (1) is 0.1 MPa - 2 MPa. For example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 1.8 MPa or 2 MPa, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable, and preferably it is 0.1 MPa - 0.5 MPa.

[0039] In step (1) of the present invention, the molar ratio of silicon tetrafluoride to solid base needs to be preferably set. Otherwise, an intermediate product similar to SiF x (OR) y will be formed, affecting the subsequent reaction.

[0040] Preferably, the molar ratio of silicon tetrafluoride to the solid base in the solid base solution in step (1) is 1:1 - 1:20. For example, it can be 1:1, 1:2, 1:4, 1:5, 1:6, 1:8, 1:10, 1:12, 1:15, 1:18 or 1:20, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable, and preferably it is 1:4 - 1:10.

[0041] Preferably, the mass ratio of the solid base to the solvent in the solid base solution in step (1) is 1:1 - 1:100. For example, it can be 1:1, 1:5, 1:10, 1:15, 1:20, 1:30, 1:40, 1:50, 1:60, 1:80 or 1:100, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable, and preferably it is 1:10 - 1:20.

[0042] Preferably, the hydrotreating in step (2) is carried out in a fixed-bed reactor equipped with a hydrotreating catalyst. The present invention does not further limit the specific type of the hydrotreating catalyst, as long as it can achieve the hydrotreating of the first intermediate product.

[0043] During the hydrotreating in step (2), when the hydrogen dosage is excessive, it affects the reaction efficiency and causes the reaction rate to be too slow; while when the hydrogen dosage is too low, the conversion rate of the reaction decreases, affecting the reaction efficiency.

[0044] Preferably, during the hydrotreating in step (2), the molar ratio of the first intermediate product to hydrogen is 1:1 - 1:20. For example, it can be 1:1, 1:4, 1:5, 1:8, 1:10, 1:12, 1:15, 1:16, 1:18, or 1:20. However, it is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable. Preferably, it is 1:4 - 1:8.

[0045] Preferably, the temperature of the hydrotreating in step (2) is 100°C - 400°C. For example, it can be 100°C, 150°C, 200°C, 250°C, 280°C, 300°C, 320°C, 350°C, 380°C, or 400°C. However, it is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable. Preferably, it is 250°C - 300°C.

[0046] Preferably, the gauge pressure of the hydrotreating in step (2) is 0 MPa - 6 MPa. For example, it can be 0 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, or 6 MPa. However, it is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable. Preferably, it is 0.5 MPa - 1.5 MPa.

[0047] Preferably, the second rectification treatment in step (2) also yields the unreacted first intermediate product.

[0048] Preferably, the unreacted first intermediate product is recycled for use in the hydrotreating in step (2).

[0049] Preferably, the disproportionation reaction in step (3) is carried out in a fixed-bed reactor equipped with a disproportionation catalyst. The present invention does not limit the specific type of the disproportionation catalyst, as long as it can achieve the purpose of the disproportionation reaction.

[0050] When the temperature of the disproportionation reaction in step (3) is too low, the disproportionation cannot occur effectively, affecting the conversion rate of the target product; while when the temperature of the disproportionation reaction is too high, by-products will be generated, reducing the selectivity of the target product.

[0051] Preferably, the temperature of the disproportionation reaction in step (3) is 50°C - 300°C. For example, it can be 50°C, 100°C, 120°C, 150°C, 180°C, 200°C, 240°C, 250°C, 280°C, or 300°C. However, it is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable. Preferably, it is 100°C - 200°C.

[0052] Preferably, the gauge pressure of the disproportionation reaction in step (3) is 0 MPa - 3 MPa. For example, it can be 0 MPa, 0.2 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, or 3 MPa. However, it is not limited to the listed values, and the remaining unlisted values within the numerical range are equally applicable. Preferably, it is 0.2 MPa - 1.5 MPa.

[0053] Preferably, the third rectification treatment in step (3) also yields a first intermediate product; the first intermediate product obtained from the third rectification treatment is recycled to the hydrogenation treatment in step (2).

[0054] As a preferred technical solution of the preparation method provided by the present invention, the preparation method comprises the following steps:

[0055] (1) Silicon tetrafluoride is contacted with a solid base solution for reaction, the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment to obtain a first intermediate product;

[0056] The temperature of the reaction is 30°C - 120°C, and the gauge pressure is 0.1 MPa - 0.5 MPa;

[0057] The molar ratio of silicon tetrafluoride to the solid base in the solid base solution is 1:4 - 1:10;

[0058] The mass ratio of the solid base to the solvent in the solid base solution is 1:10 - 1:20;

[0059] (2) The first intermediate product is subjected to a hydrogenation treatment, and the reaction product is subjected to a second rectification treatment to obtain a second intermediate product and the unreacted first intermediate product;

[0060] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:4 - 1:8;

[0061] The temperature of the hydrogenation treatment is 250°C - 300°C, and the gauge pressure is 0.5 MPa - 1.5 MPa;

[0062] The unreacted first intermediate product is recycled to the hydrogenation treatment in step (2);

[0063] (3) The second intermediate product is subjected to a disproportionation reaction, and the reaction product is subjected to a third rectification treatment to obtain silane and a first intermediate product;

[0064] The temperature of the disproportionation reaction is 100°C - 200°C, and the gauge pressure is 0.2 MPa - 1.5 MPa;

[0065] The first intermediate product obtained from the third rectification treatment is recycled to the hydrogenation treatment in step (2).

[0066] The numerical ranges described in the present invention not only include the point values exemplified above, but also any point values between the above numerical ranges that are not exemplified. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the described ranges.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The preparation method provided by the present invention uses silicon tetrafluoride as the silicon source, reducing the raw material cost; although it involves rectification treatment, the boiling point of the product is relatively higher, the purification difficulty is small and the energy consumption is lower, and it does not involve the rectification of halogen-containing substances, so the corrosion problem does not need to be considered for the rectification device, reducing the device investment; the by-product is only the fluoride salt of alkali metal, with a wide range of application fields; moreover, in the preparation method of the present invention, each raw material can be recycled, and the overall cost advantage is more obvious. Specific Embodiments

[0069] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0070] Example 1

[0071] This example provides a method for preparing silane, and the preparation method includes the following steps:

[0072] (1) Inject a solution of potassium tert-butoxide in tetrahydrofuran (112 g of potassium tert-butoxide dissolved in 1500 g of tetrahydrofuran) into a closed container under an anhydrous and oxygen-free nitrogen atmosphere, then bring the temperature and pressure to the reaction requirements, and introduce 17 g of silicon tetrafluoride gas under stirring conditions; after the introduction of the silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure in the closed container are reduced to 5 °C and normal pressure (gauge pressure 0 MPa); the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment (gauge pressure -0.05 MPa, temperature 70 °C) to obtain a first intermediate product;

[0073] The temperature of the reaction is 60 °C and the gauge pressure is 0.2 MPa;

[0074] (2) The first intermediate product is subjected to a hydrogenation treatment, and the reaction product is subjected to a second rectification treatment (gauge pressure -0.05 MPa, temperature 100 °C) to obtain a second intermediate product and the unreacted first intermediate product;

[0075] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:6;

[0076] The temperature of the hydrogenation treatment is 300 °C and the gauge pressure is 1.5 MPa;

[0077] The unreacted first intermediate product is recycled for the hydrotreating in step (2);

[0078] (3) The second intermediate product undergoes a disproportionation reaction, and the reaction product is subjected to a third rectification treatment (gauge pressure 0 MPa, temperature 20 °C) to obtain silane and a first intermediate product;

[0079] The temperature of the disproportionation reaction is 150 °C and the gauge pressure is 0.8 MPa;

[0080] The first intermediate product obtained from the third rectification treatment is recycled for the hydrotreating in step (2); the silane is post-treated to obtain electronic-grade silane.

[0081] Example 2

[0082] This example provides a method for preparing silane, and the preparation method includes the following steps:

[0083] (1) Inject a DMSO solution of potassium ethoxide (85 g of potassium ethoxide dissolved in 850 g of DMSO) into a closed container under an anhydrous, oxygen-free nitrogen atmosphere, then bring the temperature and pressure to the reaction requirements, and introduce 20.8 g of silicon tetrafluoride gas under stirring; after the introduction of the silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure in the closed container are reduced to 5 °C and atmospheric pressure (gauge pressure 0 MPa); the reaction material is filtered and separated, and the liquid-phase product is subjected to a first rectification treatment (gauge pressure -0.08 MPa, temperature 100 °C) to obtain a first intermediate product;

[0084] The temperature of the reaction is 55 °C and the gauge pressure is 0.2 MPa;

[0085] (2) The first intermediate product undergoes a hydrotreating, and the reaction product is subjected to a second rectification treatment (gauge pressure -0.05 MPa, temperature 100 °C) to obtain a second intermediate product and an unreacted first intermediate product;

[0086] During the hydrotreating, the molar ratio of the first intermediate product to hydrogen is 1:4;

[0087] The temperature of the hydrotreating is 250 °C and the gauge pressure is 0.5 MPa;

[0088] The unreacted first intermediate product is recycled for the hydrotreating in step (2);

[0089] (3) The second intermediate product undergoes a disproportionation reaction, and the reaction product is subjected to a third rectification treatment (gauge pressure 0 MPa, temperature 10 °C) to obtain silane and a first intermediate product;

[0090] The temperature of the disproportionation reaction is 100 °C and the gauge pressure is 0.2 MPa;

[0091] The first intermediate product obtained from the third rectification treatment is recycled to the hydrogenation treatment described in step (2); the silane is post-treated to obtain electronic-grade silane.

[0092] Example 3

[0093] This example provides a method for preparing silane, and the preparation method includes the following steps:

[0094] (1) Inject a THF solution of sodium isopropoxide (82 g of sodium isopropoxide dissolved in 1640 g of THF) into a closed container under an anhydrous, oxygen-free nitrogen atmosphere, then bring the temperature and pressure to the reaction requirements, and introduce 10.4 g of silicon tetrafluoride gas under stirring conditions; after the introduction of the silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure in the closed container are reduced to 5 °C and normal pressure (gauge pressure 0 MPa); the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment (gauge pressure -0.05 MPa, temperature 70 °C) to obtain a first intermediate product;

[0095] The temperature of the reaction is 120 °C and the gauge pressure is 0.3 MPa;

[0096] (2) The first intermediate product is subjected to hydrogenation treatment, and the reaction product is subjected to a second rectification treatment (gauge pressure -0.05 MPa, temperature 100 °C) to obtain a second intermediate product and the unreacted first intermediate product;

[0097] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:8;

[0098] The temperature of the hydrogenation treatment is 300 °C and the gauge pressure is 1 MPa;

[0099] The unreacted first intermediate product is recycled to the hydrogenation treatment described in step (2);

[0100] (3) The second intermediate product is subjected to a disproportionation reaction, and the reaction product is subjected to a third rectification treatment (gauge pressure 0 MPa, temperature 20 °C) to obtain silane and a first intermediate product;

[0101] The temperature of the disproportionation reaction is 200 °C and the gauge pressure is 1.5 MPa;

[0102] The first intermediate product obtained from the third rectification treatment is recycled to the hydrogenation treatment described in step (2); the silane is post-treated to obtain electronic-grade silane.

[0103] Example 4

[0104] This example provides a method for preparing silane, and the preparation method includes the following steps:

[0105] (1) Inject a sodium methoxide solution (54 g of sodium methoxide dissolved in 54 g of solvent, where the solvent is methanol and DMSO with a mass ratio of 1:1) into a sealed container under an anhydrous, oxygen-free nitrogen atmosphere. Then, adjust the temperature and pressure to meet the reaction requirements, and introduce 104 g of silicon tetrafluoride gas under stirring conditions. After the introduction of silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure inside the sealed container drop to 5 °C and atmospheric pressure (gauge pressure 0 MPa). Filter and separate the reaction materials, and subject the liquid-phase product to the first rectification treatment (gauge pressure -0.09 MPa, temperature 80 °C) to obtain the first intermediate product;

[0106] The temperature of the reaction is 30 °C and the gauge pressure is 0.1 MPa;

[0107] (2) Subject the first intermediate product to a hydrogenation treatment. The reaction product is subjected to the second rectification treatment (gauge pressure -0.05 MPa, temperature 100 °C) to obtain the second intermediate product and the unreacted first intermediate product;

[0108] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:10;

[0109] The temperature of the hydrogenation treatment is 100 °C and the gauge pressure is 0 MPa;

[0110] The unreacted first intermediate product is recycled to the hydrogenation treatment described in step (2);

[0111] (3) Subject the second intermediate product to a disproportionation reaction. The reaction product is subjected to the third rectification treatment (gauge pressure 0 MPa, temperature 10 °C) to obtain silane and the first intermediate product;

[0112] The temperature of the disproportionation reaction is 50 °C and the gauge pressure is 0 MPa;

[0113] The first intermediate product obtained from the third rectification treatment is recycled to the hydrogenation treatment described in step (2); The silane is subjected to post-treatment to obtain electronic-grade silane.

[0114] Example 5

[0115] This example provides a method for preparing silane. The preparation method includes the following steps:

[0116] (1) Inject a potassium isopropoxide solution (98 g of potassium isopropoxide dissolved in 4000 g of solvent, where the solvent is isopropanol and THF in a mass ratio of 1:1) into a sealed container under an anhydrous, oxygen-free nitrogen atmosphere. Then, adjust the temperature and pressure to the reaction requirements, and introduce 10.4 g of silicon tetrafluoride gas under stirring conditions. After the introduction of silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure inside the sealed container are reduced to 5°C and atmospheric pressure (gauge pressure 0 MPa). Filter and separate the reaction materials, and subject the liquid-phase product to the first distillation treatment (gauge pressure -0.05 MPa, temperature 70°C) to obtain the first intermediate product;

[0117] The temperature of the reaction is 80°C and the gauge pressure is 1 MPa;

[0118] (2) Subject the first intermediate product to a hydrogenation treatment. The reaction product is subjected to the second distillation treatment (gauge pressure -0.05 MPa, temperature 100°C) to obtain the second intermediate product and the unreacted first intermediate product;

[0119] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:15;

[0120] The temperature of the hydrogenation treatment is 350°C and the gauge pressure is 3 MPa;

[0121] The unreacted first intermediate product is recycled to the hydrogenation treatment described in step (2);

[0122] (3) Subject the second intermediate product to a disproportionation reaction. The reaction product is subjected to the third distillation treatment (gauge pressure 0 MPa, temperature 10°C) to obtain silane and the first intermediate product;

[0123] The temperature of the disproportionation reaction is 150°C and the gauge pressure is 2 MPa;

[0124] The first intermediate product obtained from the third distillation treatment is recycled to the hydrogenation treatment described in step (2); The silane is subjected to post-treatment to obtain electronic-grade silane.

[0125] Example 6

[0126] This example provides a method for preparing silane, and the preparation method includes the following steps:

[0127] (1) Inject a solution of sodium tert-butoxide in tert-butanol (85 g of sodium tert-butoxide dissolved in 8500 g of tert-butanol) into a sealed container under an anhydrous, oxygen-free nitrogen atmosphere. Then, bring the temperature and pressure to the reaction requirements, and introduce 5.4 g of silicon tetrafluoride gas under stirring conditions. After the introduction of silicon tetrafluoride gas is completed, continue stirring and slowly cool down until the temperature and pressure in the sealed container drop to 5°C and atmospheric pressure (gauge pressure 0 MPa). The reaction material is filtered and separated, and the liquid-phase product is subjected to a first distillation treatment (gauge pressure -0.05 MPa, temperature 70°C) to obtain a first intermediate product;

[0128] The temperature of the reaction is 30°C and the gauge pressure is 2 MPa;

[0129] (2) The first intermediate product is subjected to a hydrogenation treatment. The reaction product is subjected to a second distillation treatment (gauge pressure -0.05 MPa, temperature 100°C) to obtain a second intermediate product and the unreacted first intermediate product;

[0130] During the hydrogenation treatment, the molar ratio of the first intermediate product to hydrogen is 1:20;

[0131] The temperature of the hydrogenation treatment is 400°C and the gauge pressure is 6 MPa;

[0132] The unreacted first intermediate product is recycled to the hydrogenation treatment described in step (2);

[0133] (3) The second intermediate product undergoes a disproportionation reaction. The reaction product is subjected to a third distillation treatment (gauge pressure 0 MPa, temperature 20°C) to obtain silane and the first intermediate product;

[0134] The temperature of the disproportionation reaction is 300°C and the gauge pressure is 3 MPa;

[0135] The first intermediate product obtained from the third distillation treatment is recycled to the hydrogenation treatment described in step (2); The silane is subjected to a post-treatment to obtain electronic-grade silane.

[0136] In the preparation methods provided in Examples 1 - 6, after repeating three cycles, the yield of silane obtained in step (3) is calculated based on the amount of silicon tetrafluoride used, and the results are shown in Table 1.

[0137] Table 1

[0138]

[0139]

[0140] The preparation method provided by the present invention uses silicon tetrafluoride as a silicon source, reducing the raw material cost; although it involves rectification treatment, the boiling point of the product is relatively higher, the purification difficulty is small and the energy consumption is lower, and it does not involve the rectification of halogen-containing substances, so the corrosion problem of the rectification device does not need to be considered, reducing the device investment; the by-product is only the fluoride salt of alkali metal, and it has a wide range of application fields; moreover, in the preparation method of the present invention, each raw material can be recycled, and the overall cost advantage is more obvious.

[0141] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing silane, characterized in that, The preparation method comprises the following steps: (1) Silicon tetrafluoride is contacted with a solid base solution for reaction, the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment to obtain a first intermediate product; (2) The first intermediate product is subjected to a hydrogenation treatment, and the reaction product is subjected to a second rectification treatment to obtain a second intermediate product; (3) The second intermediate product is subjected to a disproportionation reaction, and the reaction product is subjected to a third rectification treatment to obtain silane.

2. The preparation method according to claim 1, characterized in that, The solid base in the solid base solution includes any one or a combination of at least two of sodium methoxide, sodium ethoxide, sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium methoxide, potassium ethoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide or potassium tert-butoxide; Preferably, the solid base in the solid base solution includes any one or a combination of at least two of sodium n-propoxide, sodium isopropoxide, sodium n-butoxide, sodium isobutoxide, sodium tert-butoxide, potassium n-propoxide, potassium isopropoxide, potassium n-butoxide, potassium isobutoxide or potassium tert-butoxide.

3. The preparation method according to claim 1, wherein, The solvent in the solid base solution includes any one or a combination of at least two of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, dimethyl sulfoxide, tetrahydrofuran or N,N-dimethylformamide; 4. The preparation method according to claim 1, characterized in that, The temperature of the reaction in step (1) is 30°C - 200°C, preferably 30°C - 120°C; Preferably, the gauge pressure of the reaction in step (1) is 0.1 MPa - 2 MPa, preferably 0.1 MPa - 0.5 MPa.

5. The preparation method according to any one of claims 1-4, characterized in that The molar ratio of silicon tetrafluoride to the solid base in the solid base solution in step (1) is 1:1 - 1:20, preferably 1:4 - 1:10; Preferably, the mass ratio of the solid base to the solvent in the solid base solution in step (1) is 1:1 - 1:100, preferably 1:10 - 1:

20.

6. The preparation method according to claim 1, wherein, When performing the hydrogenation treatment in step (2), the molar ratio of the first intermediate product to hydrogen is 1:1 - 1:20, preferably 1:4 - 1:8; Preferably, the temperature of the hydrogenation treatment in step (2) is 100°C - 400°C, preferably 250°C - 300°C; Preferably, the gauge pressure of the hydrogenation treatment in step (2) is 0 MPa - 6 MPa, preferably 0.5 MPa - 1.5 MPa.

7. The preparation method according to claim 1 or 6, characterized in that The second rectification treatment in step (2) also obtains the unreacted first intermediate product; Preferably, the unreacted first intermediate product is recycled to the hydrogenation treatment in step (2).

8. The preparation method according to claim 1, characterized in that, The temperature of the disproportionation reaction in step (3) is 50°C - 300°C, preferably 100°C - 200°C; Preferably, the gauge pressure of the disproportionation reaction in step (3) is 0 MPa - 3 MPa, preferably 0.2 MPa - 1.5 MPa.

9. The preparation method according to claim 1 or 8, characterized in that, The third rectification treatment in step (3) also obtains the first intermediate product; The first intermediate product obtained by the third rectification treatment is recycled to the hydrogenation treatment in step (2).

10. The preparation method according to claim 1, characterized in that, The preparation method comprises the following steps: (1) Silicon tetrafluoride is contacted with a solid base solution for reaction, the reaction materials are filtered and separated, and the liquid-phase product is subjected to a first rectification treatment to obtain a first intermediate product; The temperature of the reaction is 30°C - 120°C, and the gauge pressure is 0.1 MPa - 0.5 MPa; The molar ratio of silicon tetrafluoride to the solid base in the solid base solution is 1:4 - 1:10; The mass ratio of the solid base to the solvent in the solid base solution is 1:10 - 1:20; (2) The first intermediate is subjected to hydrogenation treatment, and the reaction product is subjected to a second rectification treatment to obtain a second intermediate and the unreacted first intermediate; During the hydrogenation treatment, the molar ratio of the first intermediate to hydrogen is 1:4 - 1:8; The temperature of the hydrogenation treatment is 250°C - 300°C, and the gauge pressure is 0.5 MPa - 1.5 MPa; The unreacted first intermediate is recycled to the hydrogenation treatment described in step (2); (3) The second intermediate undergoes a disproportionation reaction, and the reaction product is subjected to a third rectification treatment to obtain silane and the first intermediate; The temperature of the disproportionation reaction is 100°C - 200°C, and the gauge pressure is 0.2 MPa - 1.5 MPa; The first intermediate obtained by the third rectification treatment is recycled to the hydrogenation treatment described in step (2).

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