Preparation method of monochlorosilane
By preparing a solid-supported catalyst using palladium salt-supported porous supports, and combining gas-phase or liquid-phase methods to control reaction conditions with two distillation processes, the problems of poor catalyst stability, low selectivity, and high safety risks were solved, achieving efficient, safe, and high-purity preparation of monochlorosilanes.
Patent Information
- Application Number
- CN202511669666.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-02-10
AI Technical Summary
Existing methods for preparing monochlorosilanes suffer from poor catalyst stability, low selectivity, high safety risks, and difficult separation. Traditional batch operations are also difficult to control, resulting in low monochlorosilane yields and high purification costs.
A supported catalyst was prepared by loading palladium salt onto a porous support, and monochlorosilane was generated by hydrochlorination. The reaction conditions were controlled by gas-phase or liquid-phase methods, and two distillation processes were performed to improve selectivity and purity.
It significantly improves the selectivity and yield of monochlorosilanes, reduces safety risks, is suitable for continuous industrial production, enhances catalyst stability and active site utilization, makes the reaction more controllable, and reduces the formation of by-products.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of preparation of silane chlorides, and in particular, the present application provides a preparation method of monochlorosilane. BACKGROUND
[0002] Monochlorosilane (H3SiCl) is an important organosilicon intermediate, which can be used as a precursor of high-purity silane, hydrogen silicone oil and organosilane coupling agent, and can also be used in the fields of photovoltaic, semiconductor, silane modified resin and vapor deposition. Due to the single chlorine atom and three active Si-H bonds in its molecular structure, monochlorosilane has high reactivity and selectivity in organosilicon synthesis. The current preparation of monochlorosilane mainly includes three types of methods: (1) direct chlorination method: silane (SiH4) is reacted with chlorine or hydrogen chloride to obtain monochlorosilane. This method has a fast reaction rate, but the heat release is intense, and side reactions are easy to occur to generate dichlorosilane, trichlorosilane or even silicon tetrachloride, resulting in poor selectivity of the product; at the same time, there is a high safety risk in the chlorination process; (2) indirect reduction chlorination method: high-chlorine silane is used as raw material to generate low-chlorine silane through selective hydrogenation or reduction reaction. This process has many steps, a complex catalyst system and high energy consumption; (3) organic substitution method: monochlorosilane is obtained through conversion or exchange reaction of organic chlorosilane, but the raw materials are expensive and the by-products are difficult to separate.
[0003] In the above methods, the direct chlorination method has the advantages of short process route and cheap raw materials, and is the focus of current industry. However, the existing technology generally has the following problems: poor stability of catalyst: the commonly used AlCl3 or FeCl3 catalysts are easy to sublimate and deliquesce, and it is difficult to maintain the active structure during the reaction; low selectivity of product: under high temperature conditions, silane molecules are easy to be continuously chlorinated to generate a mixture of poly-chlorosilane, resulting in low yield of monochlorosilane; high safety risk: the reaction of SiH4 with chlorine or HCl is strongly exothermic, and there is a risk of burning and explosion, which is difficult to effectively control in traditional batch operation; difficult separation: the boiling points of chlorosilane components are similar, and the energy consumption of traditional rectification is high, and the purification cost is large.
[0004] In order to solve the above problems, researchers try to introduce a heterogeneous catalytic system in the chlorination reaction to improve the selectivity. For example, the use of Pd, Pt, Ni and other noble metal catalysts can promote the activation of Si-H bond, but they are easy to be chlorinated or deactivated in the chlorination medium, and have a limited service life.
[0005] Therefore, there is an urgent need for a monochlorosilane preparation method with high activity, high selectivity and safety controllability, which can realize the selective chlorination of SiH4 under relatively mild conditions, and has good industrialization implementation. SUMMARY
[0006] The present application aims to solve at least one of the above problems.
[0007] The application provides a preparation method of monochlorosilane, comprising the following steps: S100, preparation of a catalyst: loading the catalyst on a porous carrier to obtain a supported catalyst; S200, preparation of monochlorosilane: using silane and hydrogen chloride as raw materials, and adopting the supported catalyst to perform a hydrochlorination reaction to obtain monochlorosilane; The catalyst comprises a palladium salt.
[0008] In the technical solution, S100 comprises: S110, dissolving the palladium salt in an organic solvent to obtain a palladium salt solution; S120, immersing the porous carrier in the palladium salt solution to obtain an immersed carrier; S130, sequentially performing drying treatment and reduction treatment on the immersed carrier to obtain the supported catalyst.
[0009] In any of the technical solutions, the palladium salt comprises at least one of palladium acetate, palladium chloride or palladium nitrate or a combination thereof; and / or the porous carrier comprises at least one of activated carbon, molecular sieve and aluminosilicate or a combination thereof.
[0010] In any of the technical solutions, the drying treatment is performed in an inert gas atmosphere; and / or the temperature of the drying treatment is 100-200 DEG C; and / or the time of the drying treatment is 2-10 h; and / or the reduction treatment is performed in a hydrogen atmosphere; and / or the temperature of the reduction treatment is 150-250 DEG C.
[0011] In any of the technical solutions, the porous carrier is a porous carrier subjected to surface modification treatment, and the surface modification treatment comprises the following steps: S121, immersing the porous carrier in hydrogen chloride or a chlorinated solvent for immersion treatment.
[0012] In any of the technical solutions, S100 and S200 further comprise: S140, activating the supported catalyst by using hydrogen or argon at 150-250 DEG C.
[0013] In S200 of any of the technical solutions, the hydrochlorination reaction is performed by using a gas phase method or a liquid phase method.
[0014] In the gas phase method, the molar ratio of silane to hydrogen chloride is 1: (1.0-1.2); and / or the temperature of the hydrochlorination reaction is 50-200 DEG C; and / or the time of the hydrochlorination reaction is 10-60 min; and / or the loading volume space velocity of the supported catalyst is 200-800 h-1; and / or the pressure of the hydrochlorination reaction is 0.1-0.2 MPa. -1
[0015] In any of the technical solutions above, in the liquid phase method, the molar ratio of methanol and hydrogen chloride is 1:(1-1.5); and / or the temperature of the hydrochlorination reaction is 40-80 DEG C; and / or the time of the hydrochlorination reaction is 20-30 min; and / or the pressure of the hydrochlorination reaction is 0.5-1.0 MPa.
[0016] In any of the technical solutions above, the preparation method further comprises: S300, performing rectification treatment on monochlorosilane; the rectification treatment comprises first rectification treatment and second rectification treatment.
[0017] After the technical solutions of the present application are adopted, the following technical effects can be achieved: (1) By using the monochlorosilane preparation method of the supported catalytic system, a mild and selective chlorination reaction is realized, thereby significantly improving the selectivity and yield of monochlorosilane, reducing the safety risk, and being suitable for continuous industrial production; (2) By uniformly dispersing the catalytically active component on the porous carrier with a large specific surface area, the utilization rate of active sites and the contact probability of reactants are significantly improved, so that the rate and selectivity of the hydrochlorination reaction are both improved; (3) The catalyst uses palladium salt, and palladium has excellent hydrogenation and dehydrogenation capacity, can efficiently adsorb and activate the Si-H bond in silane, form an active Pd-H intermediate in the reaction process, and make the chlorine atom in HCl preferentially undergo monochlorination, thereby generating H3SiCl. BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION
[0019] In order to more clearly understand the above objectives, features and advantages of the present application, the present application will be further described in detail below with specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.
[0020] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.
[0021] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below.
[0022] In the related art, monochlorosilane is mainly prepared by direct chlorination method, indirect reduction chlorination method or organic substitution method. However, the direct chlorination method has the advantages of short process route and cheap raw materials, and is the focus of the industry. However, the existing technology generally has the following problems: poor stability of the catalyst: the commonly used AlCl3 or FeCl3 catalyst is easy to sublimate and deliquesce, and it is difficult to maintain the active structure during the reaction; low product selectivity: under high temperature conditions, silane molecules are easy to be continuously chlorinated to generate a mixture of polychlorosilane, resulting in a low yield of monochlorosilane; high safety risk: the reaction of SiH4 and chlorine or HCl is strongly exothermic, and there is a risk of burning and explosion, which is difficult to effectively control by traditional batch operation; difficult separation: the boiling points of chlorosilane components are similar, and the energy consumption of traditional rectification is high, and the purification cost is large.
[0023] Therefore, embodiments of the present application provide a preparation method of monochlorosilane, which realizes a mild and selective chlorination reaction by using a monochlorosilane preparation method of a supported catalyst system, thereby significantly improving the selectivity and yield of monochlorosilane, reducing the safety risk, and being suitable for continuous industrial production.
[0024] Specifically, the present application provides a preparation method of monochlorosilane, comprising the following steps: S100, preparation of a catalyst: loading the catalyst on a porous carrier to obtain a supported catalyst; S200, preparation of monochlorosilane: using silane and hydrogen chloride as raw materials, and adopting the supported catalyst to perform a hydrochlorination reaction to obtain monochlorosilane.
[0025] Preferably, the present application catalyzes the reaction of silane and hydrogen chloride to generate monochlorosilane by using a supported catalyst. Compared with traditional homogeneous or non-supported catalyst systems, the supported catalyst has better catalytic performance and process advantages. By uniformly dispersing the catalytically active component on a porous support with a large specific surface area, the utilization rate of active sites and the contact probability of reactants are significantly improved, which improves the rate and selectivity of the hydrochlorination reaction. The mesoporous structure of the porous support is beneficial to the diffusion and mass transfer of silane and hydrogen chloride molecules, promoting the reaction efficiency at the gas-solid interface. At the same time, the good thermal conductivity of the support can quickly conduct the reaction heat, avoiding the accumulation of hot spots and causing side reactions. The supported structure can also effectively fix the active component, preventing the catalyst from being lost, volatilized or agglomerated in a high-temperature or chlorinated environment, significantly improving the thermal stability and anti-inactivation ability of the catalyst. In addition, by adjusting the acidity and basicity of the support surface and the functional groups, the adsorption configuration of the reaction intermediates can be optimized, the monochlorination reaction can be promoted, and the generation of polychlorinated by-products can be inhibited, thereby obtaining monochlorosilane with higher purity. In terms of process, the supported catalyst is suitable for continuous reaction devices such as fixed bed or fluidized bed, which is easy to control temperature and atmosphere, and is convenient for automation and catalyst recycling. Overall, the supported catalyst system has significant advantages in reaction rate, selectivity, stability and safety, providing a reliable technical foundation for the efficient, clean and sustainable preparation of monochlorosilane.
[0026] Preferably, the catalyst preferably uses palladium salt, which can significantly improve the preparation efficiency and selectivity of monochlorosilane. Palladium (Pd) has excellent hydrogenation and dehydrogenation ability, can efficiently adsorb and activate the Si-H bond in silane, and form active Pd-H intermediates during the reaction, so that the chlorine atom in HCl preferentially undergoes monochlorination to generate H3SiCl, while inhibiting the generation of dichlorosilane, trichlorosilane and other polychlorosilanes, realizing high selectivity reaction. Palladium salt is easily dissolved in solvent, and can be uniformly loaded on the surface of porous support by impregnation or coprecipitation method, and after reduction treatment, nanoscale highly dispersed Pd particles are formed, which increases the number of active sites per unit mass of catalyst, enhances the reaction efficiency and catalyst reuse performance. Palladium is stable in the Pd 0 / Pd 2+ cycle state in the hydrogen chloride environment, has strong resistance to chlorination inactivation, and forms an acid-metal synergistic center with the support, which not only activates the Si-H bond, but also promotes the polarization of HCl, thereby accelerating the reaction kinetics and improving the conversion rate and selectivity. At the same time, the adsorption and release ability of palladium to hydrogen helps to maintain the hydrogen balance and reaction heat management of the system, reducing the occurrence of local over-chlorination or side reactions. Overall, the palladium-based supported catalyst has obvious advantages in activity, selectivity, stability and industrial sustainability, which makes monochlorosilane efficiently generated under mild conditions and is suitable for continuous industrial production, and is the core technical route to realize green and efficient preparation.
[0027] Further, S100 comprises: S110, dissolving the palladium salt in an organic solvent to obtain a palladium salt solution; S120, immersing the porous carrier in the palladium salt solution to obtain an immersed carrier; S130, sequentially performing drying treatment and reduction treatment on the immersed carrier to obtain a supported catalyst.
[0028] Preferably, the palladium supported catalyst is prepared by solution impregnation-drying-reduction method. First, the palladium salt is dissolved in an organic solvent to form a uniform solution, and then the porous carrier is immersed in the solution. This can ensure that the palladium precursor fully penetrates the pores and surface sites of the carrier, achieving high dispersion and uniform distribution of the active component, thereby improving the activity of the catalyst per unit mass. The organic solvent is preferably ethanol, isopropanol, acetone, or acetonitrile. The palladium salt is preferably at least one of palladium acetate, palladium chloride, or palladium nitrate, or a combination thereof. These palladium salts have good solubility and can form a uniform solution, allowing the carrier to uniformly adsorb the active component during the impregnation process. At the same time, these palladium salts are easily reduced to nanoscale palladium metal particles under hydrogen or reducing atmosphere, with controllable particle size and high dispersity, thereby providing more effective active sites, enhancing catalytic activity and reaction selectivity. In addition, palladium acetate, palladium chloride, and palladium nitrate are chemically stable, making them easy to store, transport, and operate. The porous carrier includes at least one of activated carbon, molecular sieve, and aluminosilicate, or a combination thereof. Activated carbon has high specific surface area, strong chemical inertness, and adjustable pore structure, which is beneficial for palladium particle dispersion and silane molecule adsorption. Molecular sieve has uniform pore structure and surface acidity, which can synergistically activate reactants, limit particle agglomeration, and improve catalyst life. Aluminosilicate has good thermal stability and mechanical strength, which can improve reactant diffusion and heat conduction, form acid-metal synergistic centers, and further enhance monochlorination selectivity. Subsequently, the solvent is removed by drying to fix the palladium salt, and the palladium is converted to nanoscale metal particles by reduction treatment, resulting in uniform particle size and stable structure, which not only reduces the possibility of sintering and migration, but also enhances the thermal stability and chlorine resistance of the catalyst. The drying process is carried out in an inert gas atmosphere, which can effectively prevent the oxidation reaction between oxygen and water in the air and the palladium salt or carrier, avoiding the deactivation or migration of the active component. The drying temperature is 100-200°C, and the time is 2-10h, which can fully remove the solvent and adsorbed water, making the palladium salt firmly adhere to the surface of the carrier, while avoiding the collapse of the pore structure of the carrier or the agglomeration of the palladium salt due to high temperature, thereby maintaining the porous structure of the carrier and the uniform distribution of the metal precursor. The reduction treatment is carried out in a hydrogen atmosphere, and the reduction temperature is 150-250°C, which ensures sufficient reduction while avoiding high temperature-induced particle sintering or deactivation. The reasonable matching of process conditions makes the palladium particles uniform in size, high in dispersity, and firmly combined with the carrier, thereby significantly improving the activity, selectivity, and stability of the catalyst, and prolonging its cycle life, providing reliable protection for the subsequent efficient preparation of monochlorosilane. The supported catalyst is easy to separate from the reaction system and can be repeatedly used, which is suitable for gas or liquid continuous reactors and can realize industrialized continuous production. At the same time, the uniform dispersion of active sites and the pore structure of the porous carrier can improve the mass transfer and heat management of reactants, making the silane hydrogen chloride reaction more controllable, with high selectivity of H3SiCl and less by-products, thereby significantly improving the reaction efficiency and purity of the target product.
[0029] Preferably, the porous support is a surface-modified porous support, which is modified to improve the interaction between the surface of the support and the metal active component, thereby significantly improving the dispersion, stability and reaction selectivity of the catalyst.
[0030] Further, the surface modification process comprises the following steps: S121, immersing the porous support in hydrogen chloride or a chlorinated solvent for treatment.
[0031] Preferably, the porous support is immersed in hydrogen chloride or a chlorinated solvent, which introduces chlorinated groups or acidic centers on the surface of the support, thereby converting the surface of the support from neutral or weakly basic to weakly acidic or halogen-active. On the one hand, this surface modification can enhance the interaction between the palladium salt precursor and the support, promote the uniform adsorption and firm anchoring of palladium ions during the impregnation process, and prevent agglomeration and migration during subsequent drying or reduction, thereby obtaining palladium nanoparticles with small particle size and uniform distribution; on the other hand, chlorination modification can adjust the electronic environment of palladium, reduce the surface electron density of palladium, enhance the adsorption and activation ability of hydrogen chloride molecules, and improve the hydrogen chloride reaction rate and the selectivity of monochlorosilane. In addition, the surface of the support treated by chlorination is more hydrophobic, which can effectively reduce the adsorption of water or by-products during the reaction, inhibit the sintering and deactivation of metal particles at high temperature, and optimize the diffusion and desorption behavior of reactants in the pores. In summary, surface modification with hydrogen chloride or a chlorinated solvent can significantly enhance the dispersion of palladium and the metal-support interaction while maintaining the stability of the support structure, thereby endowing the catalyst with higher activity, selectivity and durability, providing a reliable guarantee for the efficient preparation of monochlorosilane.
[0032] Preferably, S100 and S200 further comprise: S140, activating the supported catalyst with hydrogen or argon at 150-250°C.
[0033] Preferably, since a small amount of impurities such as precursors, solvents, chlorides or hydroxyl groups may remain on the surface of the supported catalyst after drying and reduction, these residues may cover or hinder the metal palladium active sites, reducing their catalytic efficiency. Therefore, through activation treatment, these surface impurities can be effectively removed, promoting the surface reconstruction of metal particles, converting the partially oxidized palladium to zero-valent palladium with higher catalytic activity, and enhancing the interfacial bonding between palladium and the support, thereby stabilizing the metal particle size distribution and improving the overall activity and durability of the catalyst; compared with air, nitrogen or carbon dioxide, hydrogen and argon can keep the system pure and chemically inert during the activation process, avoiding secondary reactions or surface oxidation. Hydrogen is a reducing gas, which can further reduce the residual palladium salt or surface-oxidized palladium (PdO) to metallic palladium (Pd 0), restores its intrinsic active center, improves the electronic structure and reaction selectivity; argon is an inert gas, which can be used for heat stabilization treatment of the catalyst without introducing oxidation or chemical reaction, so that the surface structure is gradually uniform and the pore is unobstructed, while preventing metal particle aggregation or carrier oxidation; the activation temperature is selected between 150-250°C, which is based on the thermal stability of metal palladium and the carrier, the decomposition characteristics of the precursor and the metal reduction kinetics. If the temperature is lower than 150°C, the surface impurities are difficult to completely desorb or decompose, and the reduction of palladium is insufficient. If the temperature is higher than 250°C, it is easy to cause metal particle sintering, reduction of active sites or collapse of carrier structure. The temperature range of 150-250°C can ensure the complete reduction and structure uniformization of the palladium surface, and can maintain the stability of the pore and specific surface area of the carrier, achieving the balance between activation and excessive sintering.
[0034] Preferably, in S200, the hydrogen chloride reaction is carried out by gas phase method or liquid phase method. Silane and hydrogen chloride react on the surface of the catalyst to generate monochlorosilane and hydrogen. This reaction is a typical surface catalytic reaction, which depends on the adsorption, activation and intermediate conversion process of the reactants on the catalyst surface. In the gas phase method, silane and hydrogen chloride are directly contacted with the supported catalyst in the form of gas, which has small mass transfer resistance, fast reaction rate, and reaction heat can be easily removed through gas flow and external heat exchange device, so that uniform temperature distribution and continuous operation can be achieved, and therefore it is suitable for large-scale industrial production. At the same time, the gas phase method can improve the generation rate and selectivity of monochlorosilane by accurately controlling the gas flow and molar ratio. In the gas phase method, the molar ratio of silane to hydrogen chloride is 1: (1.0-1.2), which is mainly to ensure that hydrogen chloride is slightly excessive, so that the concentration of hydrogen chloride in the reaction system is always sufficient, promoting the complete conversion of silane and avoiding the decrease of yield caused by unreacted silane. If hydrogen chloride is excessively large, it will increase the side reactions and waste resources. If the temperature of the hydrogen chloride reaction is too low, the reaction rate will be slow and the conversion rate will be low. If the temperature is too high, it may cause catalyst sintering or the generation of multiple chlorinated by-products. Therefore, the temperature of the hydrogen chloride reaction is preferably 50-200°C. The reaction time is 10-60 min, which is to ensure sufficient contact and conversion of the reactants while preventing the accumulation of by-products caused by long reaction time. The loading volume space velocity of the supported catalyst is 200-800 h -1The reaction conversion rate and product selectivity can be considered, and the space velocity is too low to cause excessive chlorination of the product, and too high to cause incomplete reaction; the pressure of the hydrochlorination reaction is 0.1-0.2 MPa, which is beneficial to gas flow and heat exchange, and can ensure the safety and stability of the device. The liquid phase method dissolves silane and hydrogen chloride in a solvent to react on the liquid-solid interface, and the solvent can effectively absorb heat, buffer the reaction rate, and reduce the risk of local overheating, thereby ensuring the mildness and safety of the reaction, and the reaction path can be controlled by the solvent polarity to improve the selectivity of monochlorination; in the liquid phase method, the molar ratio of methanol to hydrogen chloride is 1: (1-1.5), which is to ensure the moderate excess of hydrogen chloride to drive the reaction equilibrium to the direction of generating monochlorosilane, while avoiding the limitation of the reaction caused by insufficient dissolution of hydrogen chloride; the temperature of the hydrochlorination reaction is 40-80℃, which can ensure the thermal stability of the solvent and provide enough activation energy to promote the reaction to proceed efficiently; too high temperature will cause side reactions or solvent evaporation; the time of the hydrochlorination reaction is 20-30 min, which ensures that the reaction reaches a high conversion rate before the thermodynamic equilibrium, and prevents the catalyst from deactivating or the product from being over-chlorinated; the pressure of the hydrochlorination reaction is 0.5-1.0 MPa, which is mainly used to improve the solubility of hydrogen chloride in the liquid phase, enhance the mass transfer efficiency of the gas-liquid interface, and significantly improve the reaction rate. Overall, the gas phase method has the advantages of high reaction rate, simple process, and easy scaling up, and is suitable for continuous production; the liquid phase method has the characteristics of mildness, safety, and adjustable selectivity, and is suitable for pilot or high selectivity refining scenarios. By reasonably selecting the reaction phase and process conditions, an optimal balance between activity, selectivity and safety can be achieved, thereby ensuring the efficient and controllable preparation of monochlorosilane.
[0035] Preferably, the preparation method further comprises: S300, subjecting monochlorosilane to rectification treatment; the rectification treatment comprises first rectification treatment and second rectification treatment. Due to the characteristics of monochlorosilane, such as strong volatility, low boiling point and easy to form azeotrope with by-products, single rectification is often difficult to achieve high-purity separation under safe and economic conditions, therefore, in the preparation process of monochlorosilane, two rectification treatments are adopted to realize step-by-step purification and fine separation of the product, so as to remove different types of impurities to the maximum extent, thereby obtaining monochlorosilane product with high purity and good stability; the first rectification is carried out at a low temperature of-10-10℃, and the main purpose is to remove low-boiling-point impurities in the reaction system, including unreacted hydrogen chloride, light chlorosilane and part of volatile organic solvent residues. Low-temperature operation can effectively control the evaporation rate of monochlorosilane, avoid the loss of target product, and at the same time improve the accuracy of impurity separation. Through this step, monochlorosilane fraction with preliminary purification can be obtained, which lays a foundation for subsequent high-precision purification. The second rectification is carried out under normal pressure or reduced pressure, and is mainly used for further removing high-boiling-point impurities and difficult-to-separate by-products. Reduced pressure operation can reduce the boiling point of the system, reduce the risk of thermal decomposition of monochlorosilane, and improve the separation efficiency of heat-sensitive components. In this step, by accurately controlling the reflux ratio and the temperature distribution of the column plate, monochlorosilane with a purity of not less than 99.5% can be effectively obtained. In summary, the process design of two rectifications embodies the principle of coarse separation first and then fine separation: the first low-temperature rectification ensures the effective removal of light impurities and the control of product yield, and the second normal pressure or reduced pressure rectification realizes the complete removal of high-boiling-point residues. This step-by-step rectification strategy not only significantly improves the product purity and quality stability, but also avoids the problems of high energy consumption, equipment corrosion and product decomposition that may be caused by single high-load rectification, thereby ensuring the safety, economy and industrial feasibility of the process.
[0036] Embodiment 1 The embodiment provides a preparation method of monochlorosilane, comprising the following steps: S100, preparation of a catalyst: loading palladium acetate on activated carbon to obtain a supported catalyst; S200, preparation of monochlorosilane: subjecting silane and hydrogen chloride to a hydrochlorination reaction by using the supported catalyst to obtain monochlorosilane; S100 comprises: S110, obtaining a palladium salt solution by dissolving palladium acetate in an organic solvent; S120, dipping activated carbon in the palladium salt solution to obtain an impregnated carrier; S130, subjecting the impregnated carrier to drying treatment at 100℃ for 10 hours, and then to reduction treatment at 150℃ to obtain the supported catalyst; In S200, the hydrochlorination reaction is performed by using a gas phase method, the molar ratio of silane and hydrogen chloride is 1:1, the temperature of the hydrochlorination reaction is 50°C, the time of the hydrochlorination reaction is 60 min, the loading volume space velocity of the supported catalyst is 200 h-1, and the pressure of the hydrochlorination reaction is 0.1 MPa. -1
[0037] Example 2 The embodiment provides a preparation method of monochlorosilane, which comprises the following steps: S100, preparation of a catalyst: loading palladium chloride on a molecular sieve to obtain a supported catalyst; S200, preparation of monochlorosilane: using silane and hydrogen chloride as raw materials, and performing a hydrochlorination reaction by using the supported catalyst to obtain monochlorosilane; S100 comprises: S110, obtaining a palladium salt solution by placing palladium chloride in an organic solvent; S120, immersing the molecular sieve in the palladium salt solution to obtain an immersed carrier; S130, performing drying treatment on the immersed carrier at 200°C for 2 hours, and then performing reduction treatment at 250°C to obtain the supported catalyst; The porous carrier is a porous carrier subjected to surface modification treatment, and the surface modification treatment comprises the following steps: S121, immersing the porous carrier in hydrogen chloride for immersion treatment.
[0038] S100 and S200 further comprise: S140, performing activation treatment on the supported catalyst by using argon at 150°C; In S200, the hydrochlorination reaction is performed by using a liquid phase method, the molar ratio of methanol and hydrogen chloride is 1:1.5, the temperature of the hydrochlorination reaction is 40°C, the time of the hydrochlorination reaction is 30 min, and the pressure of the hydrochlorination reaction is 0.5 MPa.
[0039] Example 3 The embodiment provides a preparation method of monochlorosilane, which comprises the following steps: S100, preparation of a catalyst: loading palladium chloride on a molecular sieve to obtain a supported catalyst; S200, preparation of monochlorosilane: using silane and hydrogen chloride as raw materials, and performing a hydrochlorination reaction by using the supported catalyst to obtain monochlorosilane; S300, performing first rectification treatment and second rectification treatment on the monochlorosilane; S100 comprises: S110, obtaining a palladium salt solution by placing palladium chloride in an organic solvent; S120, dipping the molecular sieve in the palladium salt solution to obtain an impregnated carrier; S130, drying the impregnated carrier at 150°C for 6h and then reducing the carrier at 200°C to obtain a supported catalyst; The porous carrier is a porous carrier subjected to surface modification treatment, and the surface modification treatment comprises the following steps: S121, dipping the porous carrier in the chlorinated solvent.
[0040] S100 and S200 also include: S140, activating the supported catalyst with hydrogen at 250°C; In S200, the hydrochlorination reaction is carried out by a gas phase method, the molar ratio of silane to hydrogen chloride is 1:1.2, the temperature of the hydrochlorination reaction is 200°C, the time of the hydrochlorination reaction is 10min, the loading volume space velocity of the supported catalyst is 200h -1 , and the pressure of the hydrochlorination reaction is 0.2MPa.
[0041] Example 4 The present embodiment provides a preparation method of monochlorosilane, comprising the following steps: S100, preparation of the catalyst: loading palladium nitrate on aluminosilicate to obtain a supported catalyst; S200, preparation of monochlorosilane: using silane and hydrogen chloride as raw materials, and carrying out a hydrochlorination reaction with the supported catalyst to obtain monochlorosilane; S300, first and second rectification treatments of monochlorosilane; S100 includes: S110, obtaining a palladium salt solution by dissolving palladium nitrate in an organic solvent; S120, dipping the aluminosilicate in the palladium salt solution to obtain an impregnated carrier; S130, drying the impregnated carrier at 120°C for 7h and then reducing the carrier at 180°C to obtain a supported catalyst; The porous carrier is a porous carrier subjected to surface modification treatment, and the surface modification treatment comprises the following steps: S121, dipping the porous carrier in the chlorinated solvent.
[0042] S100 and S200 also include: S140, activating the supported catalyst with hydrogen at 200°C; In S200, the hydrochlorination reaction is carried out by a liquid phase method, the molar ratio of methanol to hydrogen chloride is 1:1, the temperature of the hydrochlorination reaction is 80°C, the time of the hydrochlorination reaction is 20 min, and the pressure of the hydrochlorination reaction is 1.0 MPa.
[0043] Comparative Example 1 This comparative example provides a preparation method of monochlorosilane, in which monochlorosilane is prepared by reacting silane with hydrogen chloride.
[0044] Comparative Example 2 This comparative example provides a preparation method of monochlorosilane, in which monochlorosilane is prepared by reduction reaction of perchlorosilane.
[0045] Comparative Example 3 This comparative example provides a preparation method of monochlorosilane, in which monochlorosilane is obtained by conversion of organochlorosilane.
[0046] Performance Test The conversion rate of silane, the selectivity of monochlorosilane, the yield and the yield of the preparation method of monochlorosilane of Examples 1-4 and Comparative Examples 1-3 are tested respectively, and the test results are shown in Table 1.
[0047] Table 1 As can be seen from Table 1, Examples 1-4 are obviously superior to Comparative Examples in conversion rate, selectivity, yield and yield, and Example 3 is the best, which shows that the Pd supported catalyst, the modification of the carrier, the activation and the distillation process can simultaneously improve the selectivity of the reaction itself and the recovery efficiency of the downstream separation; Examples use high dispersion of palladium active sites and optimize the activation and operating temperature and pressure conditions, so that the Si-H bond is activated on the catalytic surface, thus the conversion rate is generally higher; Comparative Example 1 has poor reaction control without catalyst, and the conversion rate decreases significantly; Examples 3-4 use carrier surface modification and Pd-carrier synergistic effect, which is conducive to stabilizing the intermediate monochlorination and inhibiting continuous chlorination, and the selectivity of Examples is higher than that of Comparative Examples, and high selectivity directly leads to higher yield; the yield is determined by the conversion rate x selectivity, and the yield is further affected by the loss of distillation treatment, and Examples reduce the separation loss to a very low level by two-step distillation, while the yield of Comparative Examples is significantly lower than that of Examples due to more by-products and difficult distillation; Comparative Example 1 has serious side reactions, poor selectivity and needs longer reaction time, resulting in low yield and low yield; Comparative Examples 2 and 3 involve multi-step, reduction or conversion reactions, and the steps are more and the material loss is high, which causes difficulty in recovering intermediates and the total yield is lower than that of Examples.
[0048] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "certain embodiments", and the like are intended to indicate that the described implementation, feature, structure, material or characteristic is included in at least one embodiment or example of the application. The above described terms are not necessarily indicative of the same embodiment or example. Moreover, the described implementation, feature, structure, material or characteristic can be combined in any one or more embodiments or examples in a suitable manner.
[0049] Although the present application has been disclosed in its currently best embodiment with reference to the drawings, it will be understood that it is not limited to the details of the specific embodiment, which can be varied in many ways. It is therefore desired that the present application be construed as not limited to the specific embodiment set forth above, but rather only by the appended claims.
Claims
1. A method for preparing a monochlorosilane, characterized in that, Includes the following steps: S100, Catalyst Preparation: The catalyst is loaded onto a porous support to obtain a supported catalyst; S200, Preparation of monochlorosilane: Using silane and hydrogen chloride as raw materials, a hydrochlorination reaction is carried out using a supported catalyst to obtain the monochlorosilane; The catalyst includes a palladium salt.
2. The preparation method according to claim 1, characterized in that, S100 includes: S110. Dissolve the palladium salt in an organic solvent to obtain a palladium salt solution; S120. The porous support is immersed in the palladium salt solution to obtain the immersed support; S130. The impregnated support is subjected to drying and reduction treatments in sequence to obtain the supported catalyst.
3. The preparation method according to claim 2, characterized in that, The palladium salt comprises at least one or a combination of palladium acetate, palladium chloride, or palladium nitrate; and / or The porous support includes at least one or a combination of activated carbon, molecular sieves, and aluminosilicates.
4. The preparation method according to claim 2, characterized in that, The drying process is carried out in an inert gas atmosphere; and / or The drying process is performed at a temperature of 100-200℃; and / or The drying process takes 2-10 hours; and / or The reduction process is carried out in a hydrogen atmosphere; and / or The reduction treatment is performed at a temperature of 150-250℃.
5. The preparation method according to claim 2, characterized in that, The porous carrier is a porous carrier that has undergone surface modification treatment, which includes the following steps: S121. The porous support is impregnated in hydrogen chloride or chlorinated solvent.
6. The preparation method according to claim 1, characterized in that, Between S100 and S200, there is also: S140. The supported catalyst is activated at 150-250°C using hydrogen or argon.
7. The preparation method according to claim 1, characterized in that, In step S200, the hydrochlorination reaction is carried out using either a gas-phase method or a liquid-phase method.
8. The preparation method according to claim 7, characterized in that, In the aforementioned gas-phase method The molar ratio of the silane to the hydrogen chloride is 1:(1.0-1.2); and / or The temperature of the hydrochlorination reaction is 50-200°C; and / or The hydrochlorination reaction takes 10-60 min; and / or The loading volume space velocity of the supported catalyst is 200-800 h⁻¹. -1 ; and / or The pressure of the hydrochlorination reaction is 0.1-0.2 MPa.
9. The preparation method according to claim 7, characterized in that, In the liquid phase method The molar ratio of methanol to hydrogen chloride is 1:(1-1.5); and / or The temperature of the hydrochlorination reaction is 40-80°C; and / or The hydrochlorination reaction takes 20-30 minutes; and / or The pressure of the hydrochlorination reaction is 0.5-1.0 MPa.
10. The preparation method according to claim 1, characterized in that, The preparation method further includes: S300, The monochlorosilane is subjected to distillation treatment; the distillation treatment includes a first distillation treatment and a second distillation treatment.