CN115650240A - The preparation method of monochlorosilane - Google Patents

Abstract

The invention provides a method for preparing monochlorosilane, which includes: step S1, under the action of a catalyst, react in a reaction device with silane and chloride as raw materials to obtain a reaction product; step S2, react The product is separated and purified to obtain monochlorosilane; the above-mentioned catalyst contains metal palladium, aluminum chloride and aluminum oxide. This application uses a specific catalyst to directly synthesize monochlorosilane through silane and chloride, and the raw materials are relatively easy to obtain. Different from the disproportionation method of dichlorodihydrosilane and the symmetrical disproportionation method of silane and dichlorodihydrosilane, this method has relatively high requirements for reaction conditions. It is mild and not affected by the equilibrium reaction. The content of the product is relatively high, and it is easy to purify to obtain high-purity monochlorosilane. Moreover, the catalyst has good catalytic effect and long service life, and effectively reduces the production cost of monochlorosilane.

Description

The preparation method of monochlorosilane

technical field

The invention relates to the field of synthesis of monochlorosilane, in particular to a preparation method of monochlorosilane.

Background technique

Monochlorosilane is a silicon-based precursor, which is mainly used to react with ammonia to synthesize trisilyl ammonia. Trisilyl ammonia is used as a silicon source for semiconductor manufacturing and silicon source materials for depositing thin films such as silicon nitride, because it does not contain chlorine , widely used in memory and logic chips.

At present, the synthesis methods of monochlorosilane mainly include the neutralization method of silane and dichlorodihydrosilane and the disproportionation method of dichlorodihydrosilane.

The Chinese patent application with application number 201280008841.6 discloses a method and device for preparing monochlorosilane. The preparation method is to prepare monochlorosilane by reacting silane and dichlorodihydrosilane in the presence of a catalyst, which is called a symmetrical disproportionation reaction. In fact, it is the reverse reaction of the third step reaction of the disproportionation of trichlorosilane to prepare silane, that is, the disproportionation of silane and dichlorodihydrosilane to generate monochlorosilane; the catalyst is a weakly basic anion exchange resin, and the functional group is mainly a tertiary amine base; and finally separated and purified by rectification.

The Chinese patent application with the application number 202011623031.4 discloses a system for producing silane, monochlorosilane, dichlorosilane and hexachlorodisilane. The disproportionation reaction distillation column is used for the preparation of monochlorosilane, and trichlorosilane is used as raw material , the mixture containing monochlorosilane was prepared by two-step disproportionation, and then purified by multi-stage rectification to prepare monochlorosilane with a purity of 97%. Trichlorosilane undergoes a disproportionation reaction under the catalysis of the catalyst, and at the same time, there is an anti-disproportionation reaction in the system, and the reaction balance is broken by controlling the amount of different substances to achieve the purpose of preparing the target product.

The above two methods are essentially disproportionation reactions or anti-disproportionation reactions of chlorosilanes, and the main reaction formulas involved are as follows.

Using disproportionation reaction or anti-disproportionation reaction, under the action of catalyst, the reaction balance is broken by controlling the amount of different substances, and the preparation of monochlorosilane is realized. Since the process involves three equilibrium reactions, it is impossible to conduct directional control for a certain reaction, so that there are always mixtures of trichlorosilane, silicon tetrachloride, dichlorodihydrosilane, and monochlorosilane in the reaction product. Because the mixture involves multiple components, multi-stage rectification towers are required to separate the substances. The main disadvantages are that the equilibrium reaction is not easy to control, there are side reactions, separation and purification are difficult, and the process is complicated.

Contents of the invention

The main purpose of the present invention is to provide a method for synthesizing monochlorosilane, so as to solve the problems in the prior art that the reaction balance of monochlorosilane is difficult to control, the process flow is complicated, and the production cost is relatively high.

In order to achieve the above object, according to one aspect of the present invention, a method for preparing monochlorosilane is provided, the preparation method comprising: step S1, under the action of a catalyst, react in a reaction device with silane and chloride as raw materials , to obtain a reaction product; step S2, separating and purifying the reaction product to obtain monochlorosilane; the catalyst contains metal palladium, aluminum chloride and aluminum oxide.

Further, the catalyst also includes a carrier, and the preferred carrier is any one or more of activated carbon, molecular sieve and aluminosilicate; preferably, the content of metal palladium in the catalyst is 0.1 to 10wt%, and the content of aluminum chloride is 1～20wt%, the content of alumina is 1～20wt%; more preferably, the content of metal palladium is 1.0～7.0wt%, the content of aluminum chloride is 2.0～5.0wt%, the content of alumina is 2.0～5.0 wt%.

Further, the preparation method of the catalyst comprises: mixing palladium salt, aluminum chloride, alumina and the carrier, and calcining in a hydrogen atmosphere for 2 to 10 hours; preferably, the palladium salt is palladium acetate; preferably, the calcining temperature is 100 ~500°C, more preferably 200-300°C.

Further, the chloride is any one or more of hydrogen chloride, carbon tetrachloride and chlorine, preferably the molar ratio of chloride to silane is 1-10:1, more preferably 1-3:1.

Further, the reaction temperature in step S1 is 10-300° C., and the time is 10-60 minutes; preferably, the reaction temperature is 40-80° C., and the time is 20-30 minutes.

Further, the reaction pressure in step S1 is 10-500 kPa; preferably, the reaction pressure is 200-300 kPa.

Further, step S2 includes: passing the reaction product into a deep cooler, separating the liquid component containing the product, and purifying the liquid component to obtain monochlorosilane.

Further, the temperature in the cryocooler is -60 to 0°C, preferably -50 to -40°C, and the pressure is 10 to 500kPa.

Further, the liquid phase components are purified by rectification; preferably, the rectification is carried out in series through two-stage rectification towers; more preferably, the first rectification tower in the two-stage rectification towers is used to remove light components , the second rectification tower in the two-stage rectification tower is used for removing heavy components, and monochloromethane is distilled from the top of the second rectification tower.

Further, the pressure at the top of the first rectification tower is 50 to 800kPa, the temperature is -50 to 50°C, preferably the pressure is 100 to 200kPa, and the temperature is -15 to 5°C; and/or, the top of the second rectification tower The pressure is 50-800kPa, the temperature is -50-50°C, preferably the pressure is 50-100kPa, and the temperature is -20--10°C.

Applying the technical scheme of the present invention, a specific catalyst is used to directly synthesize monochlorosilane through silane and chloride, and the raw materials are relatively easy to obtain, which is different from the disproportionation method of dichlorodihydrosilane and the symmetrical disproportionation method of silane and dichlorodihydrosilane. The requirements for reaction conditions are relatively mild, and it is not affected by the equilibrium reaction. The content of the product in the product is relatively high, and it is easy to purify to obtain high-purity monochlorosilane. The catalyst of the present application contains metal palladium, aluminum chloride and alumina. The target and aluminum are the active substances of the catalyst, which are activated by coordination with silane, and induce the attack of chlorine source to cause chlorination reaction. Among them, trichloro Alumina can directly participate in the catalytic reaction, and alumina can provide a carrier for the reaction in the reaction. Under certain circumstances, alumina can also be converted into aluminum trichloride to participate in the catalytic reaction. Moreover, the catalyst has good catalytic effect and long service life, and effectively reduces the production cost of monochlorosilane.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 shows a schematic diagram of the preparation process according to Example 1 of the present invention.

Wherein, the above drawings include the following reference signs: 1. chloride; 2. silane; 3. reaction product; 4. gaseous component; 5. liquid component; 6. light component; 7. heavy component; 8. Chloromethane; 9, high boilers; 100, catalytic reactor; 200, deep cooler; 300, 1 rectification tower; 400, 2 rectification towers.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

As analyzed in the background technology of the present application, the preparation of monochloromethane by disproportionation reaction in the prior art has the problem that the balance is not easy to control, the product content in the product is low, and the separation process is complicated, resulting in higher production costs. In order to solve this problem, The application provides a method for preparing monochlorosilane, which includes: step S1, under the action of a catalyst, react in a reaction device with silane and chloride as raw materials to obtain a reaction product; step S2, react The product is separated and purified to obtain monochlorosilane; the above-mentioned catalyst contains metal palladium, aluminum chloride and aluminum oxide.

This application uses a specific catalyst to directly synthesize monochlorosilane through silane and chloride, and the raw materials are relatively easy to obtain. Different from the disproportionation method of dichlorodihydrosilane and the symmetrical disproportionation method of silane and dichlorodihydrosilane, this method has relatively high requirements for reaction conditions. Mild, not affected by the equilibrium reaction, the content of the product in the product is relatively high, and it is easy to purify to obtain high-purity monochlorosilane. The catalyst of the present application contains metal palladium, aluminum chloride and alumina. The target and aluminum are the active substances of the catalyst, which are activated by coordination with silane, and induce the attack of chlorine source to cause chlorination reaction. Among them, trichloro Alumina can directly participate in the catalytic reaction, and alumina can provide a carrier for the reaction in the reaction. Under certain circumstances, alumina can also be converted into aluminum trichloride to participate in the catalytic reaction. Moreover, the catalyst has good catalytic effect and long service life, and effectively reduces the production cost of monochlorosilane.

In order to increase the specific surface area of the catalyst and further improve the catalytic efficiency, the above-mentioned catalyst also includes a carrier, and metal palladium, aluminum chloride and aluminum oxide are evenly loaded on the carrier. The carrier of the above catalyst can be selected from the prior art, such as any one or more of activated carbon, molecular sieve and aluminosilicate, and the content of the carrier and each supporting component can be determined according to the loading capacity of the carrier.

In some preferred embodiments of the present application, in order to further improve the catalytic efficiency of the catalyst, the content of metal palladium in the above-mentioned catalyst is 0.1-10 wt%, the content of aluminum chloride is 1-20 wt%, and the content of aluminum oxide is 1-20 wt%. 20wt%; more preferably, the content of metal palladium is 1.0-7.0wt%, the content of aluminum chloride is 2.0-5.0wt%, the content of aluminum oxide is 2.0-5.0wt%, and the catalytic efficiency is better. The amount of the above-mentioned catalyst can be determined according to the volume of the feed, as long as it can fully contact with the reaction raw materials, because the catalyst has a stable structure, it can be used repeatedly for a long time. The above-mentioned catalyst can be prepared according to the prior art. In some preferred embodiments of the present application, the preparation method of the catalyst includes: mixing palladium salt, aluminum chloride, aluminum oxide and a carrier, and calcining in a hydrogen atmosphere for 2 to 10 hours , through high-temperature calcination, the active ingredients of the catalyst can be firmly combined on the carrier, and the pore structure is stable. In addition, the palladium salt can be reduced to a metal state in a hydrogen atmosphere. The catalyst prepared by high-temperature reduction has a more stable structure and strength. Larger, strong metal adhesion, uniform distribution, good catalytic effect and long life. Wherein the palladium salt can be common palladium salts such as palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, as preferably, the palladium salt is palladium acetate, and palladium acetate is a soluble palladium salt, which is easier to disperse during preparation, in the catalyst matrix more evenly distributed. At the same time, it is easy to decompose, and the decomposed carbon escapes in the form of carbon dioxide gas without residual impurities. Preferably, the calcination temperature is 100-500°C, more preferably 200-300°C.

Above-mentioned chloride can be selected from prior art, and in some embodiments of the present application, chloride is any one or more in hydrogen chloride, carbon tetrachloride, chlorine, wherein, when chloride is hydrogen chloride and/or or chlorine gas, the alumina in the catalyst can be converted into aluminum chloride to participate in the catalytic reaction. The molar ratio of chloride to silane can refer to the stoichiometric ratio. In some embodiments of the present application, the molar ratio of chloride to silane is 1˜10:1. Exemplary, the molar ratio of chloride to silane is 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10: 1, or any combination of both. The molar ratio of chloride and silane can affect the type of product, and the above molar ratio is conducive to reducing the content of dichlorosilane, trichlorosilane and tetrachlorosilane in the product. In some preferred embodiments, chloride and silane The molar ratio is 1 to 3:1.

The above-mentioned reaction device can be batch type or continuous type, such as a coil reactor or a fixed bed reactor, which can make the reaction material and the catalyst contact well, and has good sealing and certain pressure resistance. Can.

In some embodiments of the present application, in order to further increase the yield of the product, the temperature of the reaction in the above step S1 is 10-300° C., and the time is 10-60 minutes. If it is a continuous reaction device, the reaction time of the material in the reaction device The residence time is 10-60 min; preferably, the reaction temperature is 40-80° C. and the reaction time is 20-30 min, which can further increase the conversion rate of raw materials and the yield of monochlorosilane. In some typical embodiments of the present application, in order to improve the reaction yield, the above-mentioned catalytic reaction is carried out under a certain pressure. Generally speaking, as the pressure increases, the number of molecules of the raw material per unit volume in the reactor is more, and it is easier to combine with the catalyst. Contact and reaction, the reaction yield increases accordingly. Limited by the specific surface area of the catalyst, the influence of the pressure will gradually form a balance, that is, if the pressure continues to increase, the effect on the conversion rate will not change much, and the excessive pressure will affect the structural stability of the catalyst. Preferably, the reaction pressure in step S1 is 10-500kPa, and the pressure is gauge pressure. Unless otherwise specified in this application, all pressures represent gauge pressure; more preferably, the reaction pressure is 200-300kPa, and the yield of the target product is higher .

After the reaction is completed, the separation and purification of the product monochlorosilane can refer to the prior art. In some embodiments of the present application, the above step S2 includes: passing the reaction product into a deep cooler to obtain a liquid component containing the product, sending the gas component to the tail gas system for centralized treatment, and purifying the liquid component to obtain Monochlorosilane. In the reaction system, the boiling points of silane, hydrogen chloride, hydrogen, etc. are relatively low, and the boiling points of monochlorosilane, carbon tetrachloride, and carbon trichloride are relatively high. The separated gas components can be processed according to the methods in the prior art, for example, sent to the tail gas system for centralized treatment, and the classified recovery of materials is carried out.

In some embodiments of the present application, in order to better separate the above-mentioned gaseous components containing raw materials and liquid components containing products in the cryocooler, the temperature in the cryocooler is -60 to 0°C, preferably -50～-40℃, the pressure is 10～500kPa. With pressure in the cryocooler, on the one hand, it can increase the condensation temperature of monochlorosilane (MCS) \ dichlorosilane (DCS) \ tetrachlorosilane (STC) in the material, so that the cryocooler can control the temperature higher , saving energy consumption; on the other hand, it maintains a pressure difference with the subsequent rectification tower, and relies on the pressure difference to facilitate material transmission.

The liquid component separated by deep cooling can be further separated to obtain monochlorosilane according to the prior art. In some embodiments of the present application, the liquid component is purified by rectification. As a preference, the rectification is carried out by two-stage rectification The towers are connected in series, the first rectification tower in the two-stage rectification tower can be used to remove light components, the second rectification tower in the two-stage rectification tower is used to remove heavy components, and monochloromethane can be removed from the second rectification tower Distillate from the top of the second distillation column.

The temperature and pressure of the two-stage rectification tower can be determined according to the boiling point and content of each component in the liquid component. In some embodiments of the present application, in order to separate high-purity monochlorosilane more efficiently, the first The pressure at the top of the rectification tower is 50-800kPa, the temperature is -50-50°C, preferably the pressure is 100-200kPa, and the temperature is-15-5°C; and/or, the pressure at the top of the second rectification tower is 50 ~800kPa, temperature -50~50°C, preferably pressure 50~100kPa, temperature -20~-10°C.

The beneficial effects of the present application will be further described below in conjunction with examples and comparative examples.

Example 1

Firstly, the catalyst is prepared. The weight ratio of palladium acetate, aluminum chloride, aluminum oxide and the carrier in the catalyst is 1:3:3:93, wherein the carrier is activated carbon. The catalyst is prepared according to the following steps: Stir and mix 1 part by weight of palladium acetate, 3 parts by weight of aluminum chloride, 3 parts by weight of alumina and 93 parts by weight of activated carbon. After mixing evenly, calcinate at 200 ° C for 5 hours in a hydrogen atmosphere to obtain the catalyst .

In this embodiment, a device as shown in Figure 1 is used to prepare monochlorosilane.

In the catalytic reactor 100 that diameter is DN100, length is 1500mm, above-mentioned 2500g catalyzer is loaded, and chloride 1 is hydrogen chloride, and the mol ratio of control feed chloride 1 and silane 2 is 1:1, enters catalytic reactor 100, feed The amount is 100kg/h, the reaction temperature is controlled at 50°C, the pressure is 200kPa, the residence time is 20min, and the reaction product 3 is obtained. Using Agilent gas chromatography 7890B, the composition of the reaction product is detected by gas chromatography, wherein, in terms of molar percentage, the content of monochlorosilane is 18%, the content of silane is 22%, and the content of hydrogen chloride is 30%. , the content of dichlorodihydrosilane is 2%, the content of trichlorosilane is 2%, the content of silicon tetrachloride is 1%, and the content of hydrogen is 25%.

Pass the reaction product 3 into the cryocooler 200, the temperature is -50°C, and the control pressure is 200kPa. Under this condition, the reaction product 3 is divided into gaseous components 4 and liquid components 5, unreacted silane, hydrogen chloride and hydrogen generated by the reaction It mainly exists in the gaseous component 4, and monochlorosilane, dichlorodihydrosilane, trichlorosilane, silicon tetrachloride, etc. mainly exist in the liquid component 5, and the gaseous component 4 and the liquid component 5 are separated, The hydrogen, silane and hydrogen chloride obtained in the gaseous component 4 are sent to the tail gas system for centralized treatment.

The material of the separated liquid component 5 enters a two-stage rectification tower for rectification and purification. The rectification towers are connected in series. The first rectification tower 300 removes the light component 6, the second rectification tower 400 removes the heavy component 9, and the product monochlorosilane 8 is obtained at the top of the second rectification tower 400. The pressure at the top of the first rectifying tower 300 is 200kPa, and the temperature at the top of the tower is 0-5°C. Light components 6, hydrogen chloride and silane are extracted from the top of the first rectifying tower 300, which can be returned to the catalytic reactor 100 as raw materials for the reaction. The bottom component is the heavy component 7, which contains a mixture of monochlorosilane, dichlorodihydrosilane, trichlorosilane and silicon tetrachloride, and enters the second rectification tower 400 . The second rectifying tower 400 is a weight-removing tower, and the pressure is 50kPa, and the tower top temperature is-20°C. The product monochlorosilane 8 extracted from the tower top of the second rectifying tower 400 has a purity of 99.5% (GC). High boilers such as dichlorodihydrosilane, trichlorosilane, and silicon tetrachloride 9 are produced.

Example 2

The difference from Example 1 is that the chloride is hydrogen chloride, and the molar ratio of hydrogen chloride to silane is 3:1.

In molar percentage, the content of monochlorosilane in the reaction product is 20%, the content of silane is 15%, the content of hydrogen chloride is 39%, the content of dichlorodihydrosilane is 4%, the content of trichlorosilane The content of silicon tetrachloride is 2%, the content of silicon tetrachloride is 1%, and the content of hydrogen is 19%.

Pass the reaction product into the cryocooler at a temperature of -50°C and control the pressure at 200kPa to separate the gaseous components from the liquid components. The gaseous components contain unreacted silane, hydrogen chloride and hydrogen generated by the reaction, and the liquid components Contains monochlorosilane, dichlorodihydrosilane, trichlorosilane, silicon tetrachloride, etc.

Adopt the rectifying tower identical with embodiment 1 and rectifying condition, the first rectifying tower overhead produces hydrogen chloride and silane etc. low boiler, can be returned to catalytic reactor as the raw material of reaction; The second rectifying tower tower top The extracted product monochlorosilane has a purity of 99.5% (GC), and high boiling point substances such as dichlorodihydrosilane, trichlorosilane, and silicon tetrachloride are extracted from the tower kettle.

Example 3

The difference from Example 1 is that the chloride is chlorine, and the molar ratio of chlorine to silane is 1:1.

In molar percentage, the content of monochlorosilane in the reaction product is 16%, the content of silane is 16%, the content of hydrogen chloride is 25%, the content of dichlorodihydrosilane is 6%, the content of trichlorosilane The content of silicon tetrachloride is 2%, the content of hydrogen is 3%, and the content of chlorine is 29%.

Pass the reaction product into the cryocooler at a temperature of -40°C and control the pressure at 300kPa to separate the gaseous components from the liquid components. The gaseous components contain unreacted silane, hydrogen and hydrogen chloride produced by the reaction, and the liquid components Contains monochlorosilane, dichlorodihydrosilane, trichlorosilane, silicon tetrachloride, etc.

Using the same rectification tower and rectification conditions as in Example 1, hydrogen chloride, chlorine and silane are produced from the top of the first rectification tower, which can be returned to the catalytic reactor as raw materials for the reaction; The product monochlorosilane has a purity of 99% (GC), and dichlorodihydrosilane, trichlorosilane, silicon tetrachloride and other high boiling point substances are extracted from the tower reactor.

Example 4

The difference from Example 1 is that the molar ratio of hydrogen chloride to silane is 10:1.

The content of monochlorosilane in the reaction product is 9%, the content of silane is 4%, the content of hydrogen chloride is 68%, the content of dichlorodihydrosilane is 10%, the content of trichlorosilane is 4%, tetrachloride The silicon content is 3%, and the hydrogen content is 2%.

Example 5

The difference from Example 1 is that the weight ratio of palladium acetate, aluminum chloride, aluminum oxide, and carrier in the catalyst is 2:3:5:90.

The content of monochlorosilane in the reaction product is 28%, the content of silane is 16%, the content of hydrogen chloride is 21%, the content of dichlorodihydrosilane is 3%, the content of trichlorosilane is 2%, tetrachloride The silicon content is 1%, and the hydrogen content is 29%.

Example 6

The difference from Example 1 is that the weight ratio of palladium acetate, aluminum chloride, aluminum oxide, and carrier in the catalyst is 5:2:2:91.

The content of monochlorosilane in the reaction product is 37%, the content of silane is 14%, the content of hydrogen chloride is 13%, the content of dichlorodihydrosilane is 3%, the content of trichlorosilane is 2%, tetrachloride The silicon content is 1%, and the hydrogen content is 30%.

Example 7

The difference from Example 1 is that the weight ratio of palladium acetate, aluminum chloride, aluminum oxide, and carrier in the catalyst is 7:10:3:80.

The content of monochlorosilane in the reaction product is 30%, the content of silane is 15%, the content of hydrogen chloride is 19%, the content of dichlorodihydrosilane is 2%, the content of trichlorosilane is 2%, tetrachloride The silicon content is 1%, and the hydrogen content is 31%.

Example 8

The difference from Example 1 is that the weight ratio of palladium acetate, aluminum chloride, aluminum oxide, and carrier in the catalyst is 2:1:10:87.

The content of monochlorosilane in the reaction product is 20%, the content of silane is 24%, the content of hydrogen chloride is 26%, the content of dichlorodihydrosilane is 1%, the content of trichlorosilane is 1%, tetrachloride The content of silicon is 0, and the content of hydrogen is 28%.

Example 9

The difference from Example 1 is that when preparing the catalyst, the commercially available ZSM-5 (manufacturer: Jiangsu Jieokang Technology Co., Ltd.) molecular sieve is used instead of activated carbon in the same weight portion.

The content of monochlorosilane in the reaction product is 19%, the content of silane is 21%, the content of hydrogen chloride is 29%, the content of dichlorodihydrosilane is 1%, the content of trichlorosilane is 1%, tetrachloride The silicon content is 1%, and the hydrogen content is 28%.

Comparative example 1

The difference from Example 1 is that palladium acetate is not added during the preparation of the catalyst, and other components and ratios remain unchanged.

The content of monochlorosilane in the reaction product is 12%, the content of silane is 27%, the content of hydrogen chloride is 35%, the content of dichlorodihydrosilane is 1%, the content of trichlorosilane is 1%, tetrachloride The silicon content is 1%, and the hydrogen content is 23%.

Comparative example 2

The difference from Example 1 is that the catalyst does not contain alumina, and the proportions of other components remain unchanged.

The content of monochlorosilane in the reaction product is 16%, the content of silane is 25%, the content of hydrogen chloride is 32%, the content of dichlorodihydrosilane is 1%, the content of trichlorosilane is 1%, tetrachloride The silicon content is 1%, and the hydrogen content is 24%.

From the above description, it can be seen that this application uses a specific catalyst to directly synthesize monochlorosilane through silane and chloride, and the raw materials are relatively easy to obtain, which is different from the disproportionation method of dichlorodihydrosilane and the symmetry of silane and dichlorodihydrosilane Disproportionation method, this method requires relatively mild reaction conditions, is not affected by equilibrium reaction, and the content of the product in the product is relatively high, and it is easy to purify to obtain high-purity monochlorosilane. The catalyst of the present application contains metal palladium, aluminum chloride and alumina, wherein the target and aluminum are the active substances of the catalyst, which are activated by coordination with silane, and induce the attack of chlorine source to cause chlorination reaction, and the catalyst The catalytic effect is good, the service life is long, and the production cost of monochlorosilane is effectively reduced.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A preparation method of monochlorosilane, characterized in that, comprising: Step S1, under the action of a catalyst, react in a reaction device with silane and chloride as raw materials to obtain a reaction product; Step S2, separating and purifying the reaction product to obtain monochlorosilane; The catalyst contains metallic palladium, aluminum chloride and aluminum oxide. 2. The preparation method according to claim 1, wherein the catalyst further comprises a carrier, preferably the carrier is any one or more of activated carbon, molecular sieves and aluminosilicates; Preferably, the content of metal palladium in the catalyst is 0.1-10wt%, the content of aluminum chloride is 1-20wt%, and the content of aluminum oxide is 1-20wt%; More preferably, the content of metal palladium is 1.0-7.0 wt%, the content of aluminum chloride is 2.0-5.0 wt%, and the content of aluminum oxide is 2.0-5.0 wt%. 3. The preparation method according to claim 2, characterized in that, the preparation method of the catalyst comprises: mixing palladium salt, aluminum chloride, alumina and a carrier, and calcining in a hydrogen atmosphere for 2 to 10 hours; Preferably, the palladium salt is palladium acetate; Preferably, the calcination temperature is 100-500°C, more preferably 200-300°C. 4. preparation method according to claim 1, is characterized in that, described chloride is any one or more in hydrogen chloride, carbon tetrachloride, chlorine, and the mol ratio of preferred described chloride and silane is 1 ~10:1, more preferably 1~3:1. 5. The preparation method according to claim 1, characterized in that, the reaction temperature in the step S1 is 10-300° C., and the reaction time is 10-60 minutes; Preferably, the temperature of the reaction is 40-80° C., and the reaction time is 20-30 minutes. 6. The preparation method according to claim 1, characterized in that, the pressure of the reaction in the step S1 is 10-500 kPa; preferably the pressure of the reaction is 200-300 kPa. 7. The preparation method according to any one of claims 1 to 6, characterized in that, said step S2 comprises: passing the reaction product into a deep cooler, separating out the liquid component containing the product, and separating said liquid component Purification was carried out to obtain monochlorosilane. 8. The preparation method according to claim 7, characterized in that the temperature in the cryocooler is -60-0°C, preferably -50--40°C, and the pressure is 10-500kPa. 9. preparation method according to claim 7, is characterized in that, described liquid phase component is purified by rectification; Preferably, the rectification is carried out in series through two-stage rectification towers; More preferably, the first rectification tower in the two-stage rectification tower is used to remove light components, and the second rectification tower in the two-stage rectification tower is used to remove heavy components, monochloromethane distilled from the top of the second rectification column. 10. The preparation method according to claim 9, characterized in that the pressure at the top of the first rectifying tower is 50 to 800 kPa, the temperature is -50 to 50 °C, preferably the pressure is 100 to 200 kPa, and the temperature is -15 ~5°C; And/or, the pressure at the top of the second rectifying tower is 50-800kPa, the temperature is -50-50°C, preferably the pressure is 50-100kPa, and the temperature is -20--10°C.

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