阅读说明：本技术 一种连续生产高阶硅烷的方法 (Method for continuously producing high-order silane ) 是由 陈涵斌 陈刚军 杨高明 于 2020-12-28 设计创作，主要内容包括：本发明提供了一种连续生产高阶硅烷的方法,在30～100℃,0.05～0.5Mpa条件下,以硅化镁和酸性盐为原料在溶剂中接触进行反应,并收集所产生的气态混合物,将气态混合物在-150℃～-70℃下进行冷凝得到液态混合物；将所得的液态混合物升温至-60℃～-20℃,收集得到甲硅烷和液态混合物一,将液态混合物一继续升温至-10℃～20℃,收集得到乙硅烷和丙硅烷；其中,酸性盐选自不含有活泼氢的酸性盐,所述溶剂选自含有氨基且常压下沸点高于53℃。本发明的方法能够实现高转化率、连续化、低能耗地制备高阶硅烷。(The invention provides a method for continuously producing high-order silane, which comprises the steps of taking magnesium silicide and acid salt as raw materials to contact and react in a solvent at the temperature of 30-100 ℃ and the pressure of 0.05-0.5 Mpa, collecting a generated gaseous mixture, and condensing the gaseous mixture at the temperature of-150-70 ℃ to obtain a liquid mixture; heating the obtained liquid mixture to-60 to-20 ℃, collecting to obtain monosilane and a liquid mixture I, continuously heating the liquid mixture I to-10 to 20 ℃, and collecting to obtain disilane and trisilane; wherein the acid salt is selected from acid salts without active hydrogen, and the solvent is selected from acid salts containing amino and having a boiling point higher than 53 ℃ under normal pressure. The method can realize the preparation of high-order silane with high conversion rate, continuity and low energy consumption.)

1. A method for continuously producing high-order silane is characterized in that magnesium silicide and acid salt are used as raw materials to contact and react in a solvent under the conditions of 30-100 ℃ and 0.05-0.5 Mpa, a generated gaseous mixture is collected, and the gaseous mixture is condensed at-150-70 ℃ to obtain a liquid mixture;

heating the obtained liquid mixture to-60 to-20 ℃, collecting to obtain monosilane and a liquid mixture I, continuously heating the liquid mixture I to-10 to 20 ℃, and collecting to obtain disilane and trisilane;

wherein the acid salt is selected from acid salts without active hydrogen, and the solvent is selected from acid salts containing amino and having a boiling point higher than 53 ℃ under normal pressure.

2. The method of claim 1, wherein the reaction is carried out at 55 to 85 ℃ and 0.1 to 0.15 MPa.

3. The method according to claim 2, wherein the molar ratio of the magnesium silicide to the acid salt is 1:2 to 1:10, preferably 1:6 to 1: 8.

4. The method of any one of claims 1-3, wherein the acid salt is selected from an ammonium salt, a primary amine salt, or a hydrazine salt;

the ammonium salt is preferably selected from one or more of ammonium chloride, ammonium bromide or ammonium sulfate;

the primary amine salt is preferably selected from one or more of ethylenediamine hydrochloride, benzylamine hydrochloride and n-butylamine hydrochloride;

the hydrazine salt is preferably selected from hydrazine chloride or hydrazine bromide.

5. The method according to any one of claims 1 to 4, wherein the solvent has a boiling point of 75 ℃ to 200 ℃.

6. A process according to claim 5, characterized in that the solvent is selected from primary amines or hydrazines.

7. The method according to claim 6, wherein the primary amine is selected from the group consisting of ethylenediamine, benzylamine, n-butylamine.

8. A method according to any one of claims 1 to 7, characterized in that the collected gaseous mixture is subjected to an adsorptive cleaning and then to condensation to obtain a liquid mixture.

9. The method of claim 8, wherein the gaseous mixture is subjected to an adsorptive purification treatment with a solid acid.

10. The process according to claim 9, wherein the solid acid is selected from p-toluenesulfonic acid, solid superacids or heteropolyacids.

Technical Field

The invention relates to a continuous production method of high-order silane, in particular to continuous production of disilane and trisilane.

Background

Silane gas is an important raw material in the semiconductor and photovoltaic industries, and is mainly used for depositing various silicon-element-containing films, particularly amorphous silicon and polycrystalline silicon films. Currently, the most widely used silane gas is monosilane, but the decomposition temperature of monosilane for depositing the polysilicon film is high, the deposition rate is slow, and the application of the polysilicon film is limited to a certain extent, for example, the polysilicon film is directly deposited on a glass substrate. The high-order silane has lower decomposition temperature and higher deposition rate, and the deposited and grown film has more regular lattice arrangement, thereby being more beneficial to growing and forming the large-grain polycrystalline silicon film. For example, the temperature for growing the polysilicon film by disilane deposition can be as low as about 500 ℃ lower than the softening temperature of common glass; therefore, the process of directly depositing the polycrystalline silicon film on the surface of the glass substrate can be realized; the temperature for growing the polycrystalline silicon film by deposition of the trisilane can be lower than 300 ℃, so that the process for preparing the special composite film material by directly depositing the polycrystalline silicon film on the flexible substrate or combining with other materials such as graphene and the like is hopeful to be realized. Compared with the prior art, generally, the amorphous silicon film is deposited by taking monosilane as a raw material, and then the polycrystalline silicon film is formed by laser-induced crystal conversion, so that the preparation efficiency is low, and the development of related application technologies is severely restricted.

However, the existing industrial process routes for producing disilane mainly include a hexachlorodisilane hydrogenation method and a silicon magnesium method. Among them, the hexachlorodisilane hydrogenation method generally uses lithium aluminum hydride or sodium aluminum hydride as a reducing agent, and reacts with hexachlorodisilane in an organic solvent to produce disilane and salt, accompanied by a byproduct of chlorine. The process has the advantages of continuous production, easy production scale enlargement, complex hexachlorodisilane purification process, high difficulty, harsh preparation conditions of reducing agents lithium aluminum hydride or sodium aluminum hydride, complex whole process flow, high energy consumption, high control difficulty, high equipment investment and operation cost.

The silicon-magnesium method generally takes magnesium silicide and ammonium chloride as raw materials to react in a liquid ammonia solvent, the reaction is generally carried out under the condition of micro-positive pressure, and the temperature is controlled within the range of-20 to-30 ℃. The process is mainly used for preparing high-purity monosilane, and meanwhile, about 3-5% of disilane and a trace amount of trisilane are by-produced. The process has the advantages of short process flow, simple equipment, easy control, high purity of the obtained silane gas product and easy later purification. In this process, monosilane has a boiling point much lower than that of ammonia and is therefore easily separated from the reaction system, but higher-order silane has a boiling point higher than that of ammonia and is therefore extremely difficult to sufficiently take out higher-order silane from the reaction system. The high-order silane stays in the reaction system for too long time to cause decomposition loss, and in order to remove the high-order silane from the reaction system in time, a large amount of ammonia is brought out at the same time, the latent heat of vaporization of the ammonia is high, so the process energy consumption is high, and the ammonia loss is large; in addition, the process can only adopt intermittent operation because the magnesium chloride is a byproduct and the magnesium chloride and ammonia form a complex, namely hexammoniated magnesium chloride which is dissolved in ammonia, so that the magnesium chloride is difficult to timely remove from a reaction system. The process has the defects that continuous production is difficult to realize, and the productivity is difficult to further improve, so that the unit operation cost is high, and factories using the process to produce monosilane are gradually eliminated; the process for producing the high-order silane can simultaneously obtain disilane and trisilane, but is limited by the characteristics of the process and materials, and the high-order silane has extremely low productivity and higher energy consumption.

In conclusion, the hexachlorodisilane hydrogenation process in the prior art is complex and difficult to operate, and only disilane can be produced, the silicon-magnesium process can simultaneously produce disilane and trisilane, but only intermittent operation can be performed, the productivity is small, the yield of high-order silane is extremely low, and particularly the yield of trisilane is extremely low, so that batch production cannot be realized. Moreover, reports on the large-scale production of trisilane are not found in the prior art.

Disclosure of Invention

In view of the above, the present invention provides a method for continuously producing higher-order silane, which can realize high conversion, continuous and low energy consumption production of higher-order silane.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

the invention provides a method for preparing high-order silane continuously, which comprises the steps of contacting magnesium silicide and acid salt serving as raw materials in a solvent for reaction at the temperature of 30-100 ℃ and under the pressure of 0.05-0.5 Mpa, collecting a generated gaseous mixture, and condensing the gaseous mixture at the temperature of-150-70 ℃ to obtain a liquid mixture;

heating the obtained liquid mixture to-60 to-20 ℃, collecting to obtain monosilane and a liquid mixture I, continuously heating the liquid mixture I to-10 to 20 ℃, and collecting to obtain disilane and trisilane;

wherein the acid salt is selected from acid salts without active hydrogen, and the solvent is selected from acid salts containing amino and having a boiling point higher than 53 ℃ under normal pressure.

The method of the invention carries out reaction under specific temperature and pressure, and gaseous mixture generated in the reaction process is continuously discharged out of the reaction system and condensed to obtain liquid mixture; meanwhile, magnesium salts as by-products of the reaction are continuously accumulated in the solvent in a form of precipitation and discharged to the outside of the reaction system. Heating the liquid mixture obtained by condensation to-60 to-20 ℃, collecting monosilane which is separated from the system in a gas form, continuously heating the remaining liquid mixture to-10 to 20 ℃, collecting disilane gas, and obtaining the remaining liquid, namely trisilane, thereby realizing the continuous production of high-order silane.

The method can be carried out in a micro-negative pressure state, reduces the risk of leakage of dangerous gases such as hydrogen, silane and the like in a reaction system, and improves the safety of operation. In some specific embodiments, the reaction is carried out at 55-85 ℃ and 0.1-0.15 Mpa, so that the proportion of the high-order silane in the silane is increased.

In some specific embodiments, the molar ratio of magnesium silicide to acid salt in the reaction raw material is 1:2 to 1:10, such as 1:3, 1:5, 1: 9; in some preferred embodiments, the molar ratio of magnesium silicide to acid salt is 1:6 to 1:8, such as 1: 7.

In the process of the present invention, the acid salt in the reaction feed is selected from an ammonium salt, a primary ammonium salt or a hydrazonium salt; in some specific embodiments, the ammonium salt is preferably selected from one or more of ammonium chloride, ammonium bromide, or ammonium sulfate; the primary ammonium salt is preferably selected from one or more of ethylenediamine hydrochloride, benzylamine hydrochloride and n-butylamine hydrochloride; the hydrazine salt is preferably selected from hydrazine chloride or hydrazine bromide. In some embodiments, the acidic salt in the reaction is preferably an amine salt, a primary ammonium salt, corresponding to the solvent.

In some specific implementation processes, the reaction system is pumped to high vacuum, argon is filled to 0.05-0.5 Mpa, and then magnesium silicide and acid salt are added into the reaction system; as is well known to those skilled in the art, the magnesium silicide and the acid salt may be thoroughly mixed and then introduced into the reaction system from argon gas, or the mixed raw material powder may be introduced into the reaction system from argon gas in several portions. In some specific operation processes, part of the acid salt may be added to the solvent, and then the rest of the acid salt and the magnesium silicide may be added to the reaction system for reaction.

In the method of the invention, the reaction solvent is selected from a solvent which contains amino and has a boiling point higher than that of the higher-order silane at normal pressure, and in some preferred embodiments, the boiling point of the solvent selected by the invention is 75-200 ℃, so that the higher-order silane can be sufficiently separated from the reaction system, the decomposition loss caused by the long retention time of the higher-order silane in the reaction system is avoided, and the conversion rate of the higher-order silane is improved.

In some embodiments, the solvent is selected from a primary amine or hydrazine, the primary amine preferably being ethylenediamine, benzylamine, n-butylamine. In a specific operation process, the adding amount of the solvent can be fed according to the actual condition of the reaction, so that the reaction raw materials can be uniformly dispersed and are beneficial to stirring.

In some embodiments, the gaseous mixture collected from the reaction is subjected to an adsorption purification treatment to remove ammonia gas mixed in the gaseous mixture, and then condensed to obtain a liquid mixture. Preferably, the gaseous mixture is subjected to an adsorptive purification treatment with a solid acid, said solid acid further preferably being selected from p-toluenesulfonic acid, a solid super acid or a heteropolyacid.

By adopting the technical scheme, the method has the following technical effects:

according to the method for producing the high-order silane, the solvent which contains amino and has the boiling point higher than 53 ℃ under normal pressure is selected as the reaction medium, and the reaction is carried out at the specific temperature and pressure, so that the high-order silane obtained by the reaction can be fully separated from the reaction system, the decomposition loss caused by overlong retention time of the high-order silane in the reaction system is avoided, and the conversion rate of the high-order silane is improved.

The method for producing the high-order silane breaks through the industrialized bottleneck of the prior art, and realizes the continuous production of the high-order silane, particularly the continuous preparation of the trisilane and the large-scale preparation of the disilane.

According to the method for continuously producing the high-order silane, the reaction is not required to be carried out at low temperature, the circulation and large amount of liquid ammonia loss are not required, the operation energy consumption and the solvent material loss are obviously reduced, the process flow is simplified, and the equipment investment is reduced.

Detailed Description

In order to better understand the present invention, the following examples are provided to further illustrate the content of the present invention.

The conversion of silane was obtained in the following manner in each of the following examples:

the monosilane conversion rate ═ (actual yield of monosilane/theoretical yield of monosilane) × 100%;

disilane conversion ═ (actual disilane yield/theoretical disilane yield) × 100%;

the trisilane conversion rate ═ (trisilane actual yield/trisilane theoretical yield) × 100%.

The chemical reagents used in the method of the invention all adopt the conventional reagents in the field, and the purity is analytically pure.

Example 1

(1) Adding 1.5L of benzylamine and 343g of ammonium bromide into a reactor, stirring, adjusting the pressure to 0.08MPa, heating to 35 ℃, and maintaining the constant temperature;

(2) 2750g of ammonium bromide and 600g of magnesium silicide powder are fully and uniformly mixed, and then the mixture is pressed into the reactor by argon for ten times, and the time interval of adding each time is 20 min. Continuously extracting the generated gaseous mixture along with the reaction, performing adsorption purification treatment on the gaseous mixture through a solid acid molecular sieve to remove ammonia contained in the gaseous mixture, condensing the gaseous mixture at-140 ℃, and collecting a liquid mixture;

(3) weighing the obtained liquid mixture to obtain M; heating the liquid mixture to-55 ℃, collecting the obtained gas and the liquid mixture I, and separating and weighing the obtained gas (namely the monosilane) to obtain M1; continuing to bring the liquid mixture to-10 ℃, collecting the resulting gas and liquid, separating, and weighing the resulting gas (i.e., disilane) to a mass of M2 and the liquid (i.e., trisilane) to a mass of M3. The results of the above reaction are shown in the following table:

	quality (g)	Conversion (%)
			Silane (M)	205	82.4
Monosilane (M1)	109	43.2
			Disilane (M2)	85	34.7
Trisilane (M3)	11	4.5

Example 2

(1) Adding 1.5L benzylamine and 187g ammonium chloride into the reactor, stirring, heating to 55 deg.C, and maintaining constant temperature under normal pressure;

(2) 1500g of ammonium chloride and 600g of magnesium silicide powder are fully and uniformly mixed, and then the mixture is pressed into a reactor by argon for ten times, and the time interval of adding each time is 20 min. Continuously extracting the generated gaseous mixture along with the reaction, performing adsorption purification treatment on the gaseous mixture through a solid acid molecular sieve to remove ammonia contained in the gaseous mixture, condensing the gaseous mixture at-120 ℃, and collecting a liquid mixture;

(3) weighing the obtained liquid mixture to obtain M; heating the liquid mixture to-40 ℃, collecting the obtained gas and the liquid mixture I, and separating and weighing the obtained gas (namely monosilane) to obtain M1; the liquid mixture was continued for one to 10 ℃, the resulting gas and liquid were collected, separated and weighed to give a mass of M2 for the gas (i.e. disilane) and M3 for the liquid (i.e. trisilane). The results of the above reaction are shown in the following table:

	quality (g)	Conversion (%)
			Silane (M)	191	76.9
Monosilane (M1)	92	36.4
			Disilane (M2)	83	33.9
Trisilane (M3)	16	6.6

Example 3

(1) Adding 1L of ethylenediamine and 233g of ethylenediamine hydrochloride into a reactor, stirring, adjusting the pressure to 0.15MPa, heating to 70 ℃, and maintaining the constant temperature;

(2) 1870g ethylenediamine hydrochloride and 600g magnesium silicide powder after fully mixing, ten times by argon pressure reactor, each time the time interval is 15 min. Continuously extracting the generated gaseous mixture along with the reaction, performing adsorption purification treatment on the gaseous mixture through a solid acid molecular sieve to remove ammonia contained in the gaseous mixture, condensing the gaseous mixture at-100 ℃, and collecting a liquid mixture;

(3) weighing the obtained liquid mixture to obtain M; heating the liquid mixture to-30 ℃, collecting the obtained gas and the liquid mixture I, and separating and weighing the obtained gas (namely monosilane) to obtain M1; the liquid mixture was continued for one to 20 ℃, the resulting gas and liquid were collected, separated and weighed to give a mass of M2 for the gas (i.e. disilane) and M3 for the liquid (i.e. trisilane). The results of the above reaction are shown in the following table:

	quality (g)	Conversion (%)
			Silane (M)	202	81.2
Monosilane (M1)	112	44.3
			Disilane (M2)	76	31.1
Trisilane (M3)	14	5.8

According to the data, the method provided by the invention adopts the solvent which contains amino and has a boiling point higher than 53 ℃ under normal pressure as a reaction solvent, takes magnesium silicide and acid salt as raw materials to react at 30-100 ℃, and continuously obtains high-order silane after separating and treating a gaseous product; wherein, the conversion rate of disilane reaches more than 31.1 percent, and the conversion rate of trisilane reaches more than 4.5 percent. The method realizes the continuous production of high-order silane and breaks through the industrialized bottleneck of the prior art; meanwhile, the method for continuously producing the high-order silane does not need to circulate and consume a large amount of liquid ammonia, and reduces the operation energy consumption and the solvent material loss.