Preparation method of catalyst and preparation method of tetraethoxysilane

Abstract

The invention provides a preparation method of a catalyst and a preparation method of tetraethoxysilane. Relates to the technical field of chemical engineering. The preparation method of the catalyst comprises the steps that low-carbon metal substances and aromatic alcohol are added into a reaction kettle according to a specific proportion and stirred to be uniform, a reaction system is obtained, and the low-carbon metal substances comprise low-carbon metal alkoxide, low-carbon metal simple substances or low-carbon metal hydroxides; heating the reaction system to a reaction temperature, and keeping a specific reaction time; in the reaction process, dropwise adding a proper amount of auxiliary agent; and heating the reaction system to a separation temperature, and steaming out the low-carbon alcohol to obtain the catalyst. The method is used for achieving the effects of improving the activity and prolonging the service life of the catalyst.

Description

Technical Field

[0001] The present application relates to the field of chemical engineering technology, and in particular to a method for preparing a catalyst and a method for preparing ethyl orthosilicate. Background Art

[0002] Tetraethyl orthosilicate is an important organosilicon compound. Due to its good electrical insulation, chemical reaction characteristics and thermal stability, it is widely used in the production of aerogels, inorganic materials, organic polymer composites, SiO2 thin film deposition, semiconductor materials and anti-refractive coatings. At present, the industrial production methods of ethyl orthosilicate mainly include the silicon tetrachloride method and the silicon powder method. Most manufacturers use the silicon tetrachloride method, but its reaction will produce toxic gas HCl as a by-product, which needs to be neutralized with alkali, producing a large amount of salt, resulting in high environmental protection costs. Therefore, the silicon powder method is more widely studied.

[0003] In the related art, when preparing tetraethyl orthosilicate by the silicon powder method, the catalysts used are mostly alkali metal alkoxides and copper-based catalysts, which have defects such as short catalyst service life and low activity, resulting in large catalyst usage and high production costs. Summary of the invention

[0004] The catalyst preparation method and the tetraethyl orthosilicate preparation method provided in the present application are used to improve the activity of the catalyst, making the catalyst highly active and not easy to deactivate; at the same time, the preparation cost of tetraethyl orthosilicate is reduced and the production purity of tetraethyl orthosilicate is improved.

[0005] In a first aspect, the present application provides a method for preparing a catalyst, comprising:

[0006] Adding a low-carbon metal substance and an aromatic alcohol into a reaction kettle in a specific ratio and stirring them evenly to obtain a reaction system, wherein the low-carbon metal substance includes a low-carbon metal alkoxide, a low-carbon metal element or a low-carbon metal hydroxide;

[0007] The reaction system is heated to a reaction temperature and maintained for a specific reaction time;

[0008] During the reaction, add an appropriate amount of auxiliary agent;

[0009] The reaction system is heated to the separation temperature, the low-carbon alcohol is evaporated, and the catalyst is obtained.

[0010] In one possible embodiment, the low-carbon metal alkoxide is a metal alkoxide having a carbon number not exceeding 4 in the molecular formula.

[0011] In a possible embodiment, the metal alkoxide includes a combination of one or more of a metal methoxide, a metal ethoxide, a metal propoxide, a metal isopropoxide, a metal tert-butoxide, and a metal isobutoxide.

[0012] In a possible embodiment, the aromatic alcohol includes: benzyl alcohol, phenol, phenylethanol, bromophenol, p-nitrophenol, naphthalene methanol, indole methanol, indole ethanol, quinoline methanol, phenanthranol and naphthol or a combination of one or more thereof.

[0013] In a possible implementation, when the low-carbon metal substance is a low-carbon metal alkoxide, the specific ratio is that the mass ratio of the low-carbon metal alkoxide to the aromatic alcohol is n (low-carbon metal alkoxide): n (aromatic alcohol) = 1: (1-6).

[0014] In a possible embodiment, the auxiliary agent includes a combination of one or more substances selected from the group consisting of ethanolamine, diethanolamine, hydroxyethylethylenediamine, methyldiethanolamine, triethylamine, aniline, diisopropanolamine and N-methyldiethanolamine; and / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the amount of the auxiliary agent added to the mass of the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (auxiliary agent) = 1: (0.1~0.5).

[0015] In a possible embodiment, before heating the reaction system to the separation temperature, the method further comprises:

[0016] adding an organic entrainer to the reaction system to obtain a new reaction system;

[0017] Accordingly, the reaction system is heated to the separation temperature, and the low-carbon alcohol is evaporated to obtain the catalyst, which includes: heating the new reaction system to the separation temperature, and evaporating the low-carbon alcohol and the organic entrainer to obtain the catalyst.

[0018] In one possible embodiment, the organic entrainer includes one or a combination of two substances selected from cyclohexane, toluene, benzene, methanol and N,N-dimethylformamide;

[0019] And / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the organic entrainer to the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (organic entrainer) = 1: (1-5).

[0020] In a possible implementation manner, at least one of the following is also satisfied:

[0021] The reaction temperature ranges from 30°C to 150°C;

[0022] The reaction time ranges from 2 hours to 8 hours;

[0023] The separation temperature ranges from 60°C to 300°C.

[0024] In a second aspect, the present application provides a method for preparing tetraethyl orthosilicate, comprising:

[0025] Add silicon powder, organic solvent and catalyst into a reaction kettle, stir evenly and raise the system to reaction temperature, wherein the catalyst is prepared by the method of the first aspect or any possible implementation of the first aspect;

[0026] Anhydrous ethanol was added dropwise into the reaction kettle until no hydrogen was generated in the system, and the reaction was completed;

[0027] The system is heated to the evaporation temperature until the ethyl orthosilicate is evaporated to obtain ethyl orthosilicate.

[0028] In a possible implementation manner, at least one of the following is also satisfied:

[0029] The added mass ratio of silicon powder, organic solvent and catalyst is m (silicon powder): m (organic solvent): m (catalyst) = 1: 1.2: 0.2;

[0030] The organic solvent includes one or more of cyclohexane, benzene, toluene, methyl formate, and dimethyl carbonate;

[0031] The reaction temperature ranges from 110°C to 180°C;

[0032] The evaporation temperature ranges from 195°C to 200°C.

[0033] The preparation method of the catalyst provided by the present application and the preparation method of ethyl orthosilicate, by obtaining low-carbon metal substances and aromatic alcohols according to a specific ratio, ensure that the raw materials involved in the reaction are fully reacted, reduce the types of components that need to be separated, reduce the difficulty of separation, and then improve the purity of the catalyst. By uniformly mixing low-carbon metal substances and aromatic alcohols, the contact area between the substances is increased to ensure that the reaction proceeds smoothly. In the reaction, an appropriate amount of auxiliary agent is added dropwise to enhance the stability of the catalyst, so that the catalyst is not easy to deactivate, can maintain a high activity for a long time, and improve the product selectivity of the catalyst. By the above means, the prepared catalyst has the effect of low preparation cost, high activity, and not easy to deactivate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] Figure 1 A schematic diagram of a process for preparing a catalyst provided in an embodiment of the present application;

[0036] Figure 2 A schematic flow chart of the method for preparing tetraethyl orthosilicate provided in an embodiment of the present application.

[0037] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0039] In related technology 1, a method for preparing a catalyst for producing ethyl orthosilicate by a silicon powder method is disclosed, wherein a copper-based catalyst is used to fix an active substance on a carrier to form a catalyst. The catalyst preparation method has high requirements for reaction pressure and temperature, resulting in high preparation costs. At the same time, there are many side reactions in the process of preparing the catalyst by this method, resulting in poor purity of the catalyst and poor catalytic effect. In related technology 2, a method for preparing ethyl orthosilicate by improving the utilization rate of silicon powder is disclosed. Before preparing ethyl orthosilicate, silicon powder is activated by ultrasound, and methanol is added to the reaction raw material ethanol as a catalyst to assist the reaction catalysis. The catalyst prepared by this method has poor activity, resulting in many impurities in the prepared ethyl orthosilicate, and it is difficult to separate the ethyl orthosilicate from the product. In summary, the catalyst used in the existing silicon powder method for preparing ethyl orthosilicate has problems such as short life and poor activity, resulting in a large dosage and high cost when the catalyst is used.

[0040] The method for preparing the catalyst provided in the embodiment of the present application ensures that the preparation reaction of the catalyst can be completely reacted by accurately controlling the specific ratio between the low-carbon metal substance and the aromatic alcohol, so that the residual raw material is small and the utilization rate of the raw material is improved. By dripping an appropriate amount of auxiliary agent during the reaction process, the service life of the catalyst is extended and the activity of the catalyst is improved. After waiting for the reaction to end, the impurities are evaporated by heating to obtain the catalyst. By simplifying the separation process of the product, the cost of preparing the catalyst is reduced and the purity of the catalyst is improved.

[0041] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0042] Figure 1The schematic diagram of the process for preparing the catalyst provided in the embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes:

[0043] S101. Add a low-carbon metal substance and an aromatic alcohol into a reaction kettle in a specific ratio and stir them evenly. The low-carbon metal substance includes a low-carbon metal alkoxide, a low-carbon metal element or a low-carbon metal hydroxide.

[0044] Low-carbon metal elements are pure metals directly formed by the corresponding metal elements in low-carbon metal alkoxides, that is, the simplest form of the metal element, without other chemical bonds or compound structures. Low-carbon metal hydroxides are inorganic compounds formed by the combination of the corresponding metal elements and hydroxide particles in low-carbon metal alkoxides. Low-carbon metal substances can be composed of one or more substances among low-carbon metal alkoxides, low-carbon metal elements and low-carbon metal hydroxides.

[0045] By obtaining low-carbon metal substances and aromatic alcohols in a specific ratio, it is possible to ensure that the reaction is fully carried out. The obtained low-carbon metal substances and aromatic alcohols are added to the reactor, and the low-carbon metal substances and aromatic alcohols are fully mixed by stirring and the like, which can increase the contact area between the reaction raw materials and ensure the uniformity of the reaction.

[0046] S102, heating the system to a reaction temperature and maintaining a specific reaction time.

[0047] The reaction temperature is selected based on the thermodynamic and kinetic characteristics of the chemical reaction to ensure that the expected chemical reaction can occur between the low-carbon metal substance and the aromatic alcohol. By adjusting the reaction temperature, the reaction rate can be adjusted, the generation of by-products caused by temperature changes can be reduced, which is conducive to the generation of products and improves the quality of products. The reaction time is set based on the chemical reaction to ensure that the reaction is fully carried out and the product can be completely generated.

[0048] S103. During the reaction, add an appropriate amount of auxiliary agent.

[0049] After the system is heated to the reaction temperature, an appropriate amount of additive is added dropwise. The additive can be a solvent, a stabilizer or other functional additives. The additive can significantly extend the service life of the catalyst and improve the activity of the catalyst.

[0050] S104, heating the reaction system to a separation temperature, distilling off the low-carbon alcohol, and obtaining a catalyst.

[0051] The separation temperature includes the temperature point at which the low-carbon alcohol in the reaction system begins to evaporate significantly. Low-carbon alcohol is the part of the substance generated by the reaction of low-carbon metal substances and aromatic alcohols that does not belong to the catalyst. By heating the reaction system to the separation temperature and utilizing the difference in boiling points of different components, the low-carbon alcohol and the catalyst can be effectively separated, which can improve the purity of the catalyst.

[0052] The preparation method of the catalyst provided in the embodiment of the present application is to obtain low-carbon metal substances and aromatic alcohols in a specific ratio to ensure that the substances can fully react, so that the components that need to be separated later are reduced, the difficulty of separation is reduced, and the purity of the catalyst is improved. By uniformly mixing low-carbon metal substances and aromatic alcohols, the contact area between the substances is increased to ensure that the reaction of generating the catalyst proceeds smoothly. By dripping an appropriate amount of auxiliary agent during the reaction, the stability of the catalyst is enhanced, so that the catalyst is not easy to deactivate and can maintain a high activity for a long time. The prepared catalyst has the effects of low preparation cost, high activity, and not easy to deactivate.

[0053] In a possible embodiment, the low-carbon metal alkoxide is a metal alkoxide having a carbon number not exceeding 4 in the molecular formula.

[0054] Metal alkoxides, also known as metal alkoxides or metal esters, are compounds with the molecular formula M(OR), where M represents a metal atom and R represents an alkyl group. The alkyl part of the molecular formula of low-carbon metal alkoxides contains no more than 4 carbon atoms. Common alkyl groups with no more than 4 carbon atoms include methyl, ethyl, propyl, butyl and their corresponding isomers.

[0055] In a possible embodiment, the metal alkoxide includes a combination of one or more of a metal methoxide, a metal ethoxide, a metal propoxide, a metal isopropoxide, a metal tert-butoxide, and a metal isobutoxide.

[0056] Metal methoxide is a metal alkoxide whose alkyl part is methyl, and can be prepared by the reaction of metal atoms with methanol. Metal ethoxide is a metal alkoxide whose alkyl part is ethyl, and can be prepared by the reaction of metal atoms with ethanol. Metal propoxide and metal isopropoxide are both metal alkoxides whose alkyl part is ethyl, the alkyl part of n-propanol is n-propyl, and the alkyl part of isopropanol is isopropyl. Metal tert-butoxide is a metal alkoxide whose alkyl part is tert-butyl, and can be prepared by the reaction of metal atoms with tert-butanol. Metal isobutoxide is a metal alkoxide whose alkyl part is isobutyl, and can be prepared by the reaction of metal atoms with isobutanol.

[0057] The metal alkoxide may be composed of one of metal alkoxides selected from metal methoxide, metal ethoxide, metal propoxide, metal isopropoxide, metal tert-butoxide and metal isobutoxide. The metal alkoxide may also be composed of any two or more of metal methoxide, metal ethoxide, metal propoxide, metal isopropoxide, metal tert-butoxide and metal isobutoxide.

[0058] In a possible implementation, the aromatic alcohol includes: a combination of one or more of benzyl alcohol, phenol, phenylethyl alcohol, bromophenol, p-nitrophenol, naphthalene methanol, indole methanol, indole ethanol, quinoline methanol, phenanthranol and naphthol.

[0059] Aromatic alcohols are a class of organic compounds in which the hydrogen atoms on the side chains of the benzene rings in aromatic hydrocarbon molecules are replaced by hydroxyl groups. They can react with low-carbon metal alkoxides under appropriate conditions.

[0060] In a possible implementation, when the low-carbon metal substance is a low-carbon metal alkoxide, the specific ratio is that the mass ratio of the low-carbon metal alkoxide to the aromatic alcohol is n (low-carbon metal alkoxide): n (aromatic alcohol) = 1: (1-6).

[0061] By determining the specific ratio through the ratio of atoms participating in the reaction, precise control in the preparation process is achieved, and the production efficiency of the product is optimized. The specific ratio can be expressed by the mass ratio of low-carbon metal alkoxide and aromatic alcohol. At the same time, determining the specific ratio can significantly reduce the difficulty of subsequent separation steps. Specifically, according to the reaction characteristics and separation difficulty between the raw materials, the specific ratio is appropriately adjusted. For raw materials that are not easy to separate by physical or chemical methods, the ratio can be precisely controlled so that the difficult-to-separate raw materials are fully converted during the reaction process, avoiding the difficulty of subsequent separation of difficult-to-separate substances, and significantly reducing production costs.

[0062] When the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the low-carbon metal alkoxide to the aromatic alcohol is 1:(1-6), which means that the mass ratio of the mass of the low-carbon metal alkoxide to the mass of the aromatic alcohol can be any specific ratio of 1:1, 1:2, 1:3, 1:4, 1:5 and 1:6 or a ratio range consisting of any two of them. Preferably, the mass ratio of the low-carbon metal alkoxide to the aromatic alcohol is 1:(1.5-3).

[0063] Since different low-carbon metal alkoxides and aromatic alcohols have different ratios of atoms or ions involved in the reaction, the specific ratio values ​​given in this application are only reference ranges. During actual preparation, the numerical value of the specific ratio should be determined based on the specific substances involved in the reaction.

[0064] In a possible embodiment, the auxiliary agent includes a combination of one or more substances selected from the group consisting of ethanolamine, diethanolamine, hydroxyethylethylenediamine, methyldiethanolamine, triethylamine, aniline, diisopropanolamine and N-methyldiethanolamine; and / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the amount of the auxiliary agent added to the mass of the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (auxiliary agent) = 1: (0.1~0.5).

[0065] Adding additives in proportion can optimize the physical properties of the catalyst, such as the dispersion of active components, specific surface area and particle size, thereby improving the catalytic performance of the catalyst. By adding additives, the selectivity of the catalyst for specific products can also be improved. In addition to improving the selectivity of the catalyst for specific products, the additives can also stabilize the catalytic effect of the catalyst, so that it can maintain stable performance under different reaction conditions. When the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the low-carbon metal alkoxide to the mass ratio of the additive added is 1: (0.1~0.5), which means that the mass ratio of the low-carbon metal alkoxide to the mass ratio of the additive added can be any one of 1:0.1, 1:0.2, 1:0.3, 1:0.4 and 1:0.5, or a range consisting of any two of them.

[0066] In a possible embodiment, before heating the reaction system to the separation temperature, it also includes: adding an organic entrainer to the reaction system to obtain a new reaction system; accordingly, heating the reaction system to the separation temperature, distilling out the low-carbon alcohol, and obtaining the catalyst, including: heating the new reaction system to the separation temperature, distilling out the low-carbon alcohol and the organic entrainer, and obtaining the catalyst.

[0067] Organic entrainers are substances that can form gas-liquid equilibrium and have similar boiling points with low-carbon alcohols. Organic entrainers have the ability to form azeotropic systems with low-carbon alcohols and can change the boiling point of azeotropes. When a mixture of organic entrainers and low-carbon alcohols is heated, they evaporate together at the separation temperature to form a stable azeotrope. Organic entrainers play the role of "carrying" low-carbon alcohols to evaporate together, making it easier to evaporate low-carbon alcohols that were originally difficult to separate separately. The azeotropic effect between organic entrainers and low-carbon alcohols simplifies the separation process, reduces energy consumption and time costs, and improves the efficiency of the separation process.

[0068] Accordingly, if an azeotropic agent is added to the reaction system, in step 104, the new reaction system should be heated to the separation temperature to efficiently separate the azeotropic agent, low-carbon alcohol and catalyst to improve the purity of the catalyst.

[0069] In one possible embodiment, the organic entrainer includes one or a combination of two substances selected from cyclohexane, toluene, benzene, methanol and N,N-dimethylformamide; and / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the organic entrainer to the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (organic entrainer) = 1: (1~5).

[0070] A reasonable ratio of entrainer to low-carbon alcohol can make the distillation process more efficient, reduce energy consumption and cost. If the ratio is too high or too low, the distillation efficiency may be reduced. By precisely controlling the ratio of entrainer to low-carbon alcohol, the content of the azeotrope is ensured to be moderate and the separation efficiency is improved. When the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the low-carbon metal alkoxide to the organic entrainer is 1:(1~5), which means that the mass ratio of the low-carbon metal alkoxide to the organic entrainer can be any specific ratio of 1:1, 1:2, 1:2.5, 1:3 and 1:5 or a ratio range consisting of any two of them.

[0071] In a possible implementation manner, at least one of the following conditions is also satisfied: the reaction temperature ranges from 30°C to 150°C; the reaction time ranges from 2 hours to 8 hours; and the separation temperature ranges from 60°C to 300°C.

[0072] According to the characteristics of the low-carbon metal substance and the aromatic alcohol involved in the reaction and the characteristics of the product, the reaction temperature is set in the range of 30°C to 150°C, which means that the reaction temperature can be any specific value of 30°C, 50°C, 70°C, 90°C, 110°C, 130°C and 150°C or a range consisting of any two of them. Preferably, the reaction temperature is in the range of 50 to 120°C.

[0073] The reaction time ranges from 2 hours to 8 hours, meaning that the reaction time can be any one of 2 hours, 4 hours, 6 hours and 8 hours or a range consisting of any two of them. Preferably, the reaction time ranges from 3 hours to 6 hours.

[0074] The separation temperature includes the temperature point at which the low-carbon alcohols in the reaction system begin to evaporate significantly, and the temperature point at which the azeotropic system composed of the organic azeotrope and the low-carbon alcohols in the reaction system evaporates significantly. When the organic azeotrope is not added to the reaction system, the separation temperature is the temperature point at which the low-carbon alcohols in the reaction system begin to evaporate significantly. When the organic azeotrope is added to the reaction system, the separation temperature is the temperature point at which the azeotropic system composed of the organic azeotrope and the low-carbon alcohols in the reaction system evaporates significantly. The range of the separation temperature is 60°C to 300°C, which means that the separation temperature can be any one of 60°C, 120°C, 180°C, 240°C and 300°C, or a range composed of any two of them. Preferably, the range of the separation temperature is 80 to 160°C.

[0075] In the related art, the catalyst used in the method for preparing ethyl orthosilicate by the silicon powder method has a poor catalytic effect, poor product selectivity, and more side reactions during the preparation process. There are problems such as low raw material utilization and low production efficiency of ethyl orthosilicate, and the problem that the prepared product has many impurities and poor purity, which makes the process for preparing ethyl orthosilicate complicated and costly. The catalyst prepared by the preparation method of the catalyst provided in the embodiment of the present application is used to catalyze the preparation of ethyl orthosilicate, which can improve the utilization rate of raw materials, improve the production efficiency of ethyl orthosilicate, reduce side reactions, and reduce the difficulty of separating the ethyl orthosilicate product.

[0076] Figure 2 The schematic diagram of the process for preparing ethyl orthosilicate provided in the embodiment of the present application is as follows. Figure 2 As shown, in this embodiment Figure 1 Based on the embodiments, the preparation method of tetraethyl orthosilicate is described in detail, and the method comprises:

[0077] S201, adding silicon powder, organic solvent and catalyst into a reaction kettle, stirring evenly and then raising the system to the reaction temperature.

[0078] The catalyst is prepared by the catalyst preparation method provided in the examples of the present application and any possible implementation method. Silicon powder, organic solvent and catalyst are added to the reactor in sequence and stirred sufficiently to ensure that the components are evenly dispersed and fully contacted. Afterwards, the temperature of the reaction system is raised to the corresponding reaction temperature to activate the reactant molecules so that the silicon powder reaches the energy state required for the chemical reaction.

[0079] S202, adding anhydrous ethanol dropwise into the reaction kettle until no hydrogen is generated in the system, and the reaction is terminated.

[0080] Gradually add anhydrous ethanol to the reactor to drive the anhydrous ethanol to react with the silicon powder and organic solvent in the reactor. By observing the generation of the reaction product hydrogen, the progress and state of the reaction can be understood. When the hydrogen stops being generated, it means that the silicon powder and organic solvent in the reactor have been fully converted. At this time, stop adding anhydrous ethanol and end the reaction. Controlling the addition of anhydrous ethanol helps control the reaction rate, improve the purity of the product and the efficiency of the reaction, and avoid potential safety hazards caused by violent reactions.

[0081] S203, raising the temperature of the system to the evaporation temperature until the ethyl orthosilicate is evaporated to obtain ethyl orthosilicate.

[0082] In order to extract pure ethyl orthosilicate, the system is heated to the evaporation temperature of ethyl orthosilicate. Since the evaporation temperatures of substances in the system containing ethyl orthosilicate are different, the system containing ethyl orthosilicate is heated to the evaporation temperature of ethyl orthosilicate, and ethyl orthosilicate vapor is collected to obtain relatively pure ethyl orthosilicate. Pure ethyl orthosilicate can be obtained by condensing the collected completely evaporated ethyl orthosilicate vapor. By controlling the system temperature, the effective evaporation of ethyl orthosilicate is ensured, and the interference of other low-boiling point substances is reduced. Furthermore, the evaporation process is continuously monitored until ethyl orthosilicate is completely evaporated, which can ensure the purity and recovery rate of the product, improve the extraction efficiency of ethyl orthosilicate, and help reduce production costs.

[0083] A method for preparing ethyl orthosilicate provided in the embodiment of the present application is catalyzed by a prepared catalyst, and the prepared catalyst is used in the preparation of ethyl orthosilicate by the silicon powder method. Since the catalyst has high activity and is not easy to deactivate, it can effectively catalyze the production of ethyl orthosilicate and reduce the by-products produced by the preparation. At the same time, the substances in the components are stirred evenly to ensure that each component is fully in contact. Afterwards, the temperature is controlled so that the silicon powder reaches the energy state required for the chemical reaction, and anhydrous ethanol is gradually added dropwise to control the rate of the reaction, ensuring that there are few types of residual substances in the reactor after the reaction is completed, reducing the difficulty of separation. Finally, ethyl orthosilicate is obtained by evaporative separation to improve the purity of the prepared ethyl orthosilicate.

[0084] In a possible implementation manner, at least one of the following is also satisfied: the added mass ratio of silicon powder, organic solvent and catalyst is m (silicon powder): m (organic solvent): m (catalyst) = 1:1.2:0.2; the organic solvent includes one or more of cyclohexane, benzene, toluene, methyl formate, and dimethyl carbonate; the reaction temperature ranges from 110°C to 180°C; and the evaporation temperature ranges from 195°C to 200°C.

[0085] By controlling the ratio of silicon powder, organic solvent and catalyst, precise control of the ratio of reaction raw materials and catalyst can be achieved, thereby ensuring the quality of ethyl orthosilicate products.

[0086] The reaction temperature for preparing ethyl orthosilicate ranges from 110°C to 180°C, which means that the reaction temperature can be any one of 110°C, 130°C, 150°C, 170°C and 180°C or a range consisting of any two of them. The evaporation temperature ranges from 195°C to 200°C, which means that the evaporation temperature can be any one of 195°C, 197°C, 199°C and 200°C or a range consisting of any two of them.

[0087] In order to better understand the above exemplary embodiments of the method for preparing the catalyst, the following is further described in conjunction with specific examples. The following examples should not be construed as limiting the scope of implementation of the present application.

[0088] The present application provides examples of preparation methods of catalysts using different low-carbon metal substances and aromatic alcohols. The specific preparation process of each catalyst preparation method example will be described in detail below.

[0089] Catalyst preparation method Example 1: Sodium methoxide, a low-carbon metal alkoxide, is selected as the low-carbon metal substance participating in the reaction, and benzyl alcohol is selected as the aromatic alcohol participating in the reaction. First, sodium methoxide and benzyl alcohol are obtained in a specific ratio of 1:1.5, and the obtained sodium methoxide and benzyl alcohol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, cyclohexane is added to the reactor as an organic entrainer, wherein n (sodium methoxide): n (cyclohexane) = 1:1, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 50°C and maintained for a specific reaction time of 3 hours. During the reaction, an appropriate amount of ethanolamine is added dropwise as an auxiliary agent, wherein n (sodium methoxide): n (ethanolamine) = 1:0.1. Finally, the reaction system is heated to a separation temperature of 80°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C1.

[0090] Catalyst preparation method Example 2: Select low-carbon metal alkoxide potassium ethoxide as the low-carbon metal substance participating in the reaction, and phenylethanol as the aromatic alcohol participating in the reaction. First, potassium ethoxide and phenylethanol are obtained according to a specific ratio of n (potassium ethoxide): n (phenylethanol) = 1: 2, and the obtained potassium ethoxide and phenylethanol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, toluene is added to the reactor as an organic entrainer, wherein n (potassium ethoxide): n (toluene) = 1: 2, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 80°C and maintained for a specific reaction time of 4 hours. During the reaction, an appropriate amount of diethanolamine is added dropwise as an auxiliary agent, wherein n (potassium ethoxide): n (diethanolamine) = 1: 0.2. Finally, the reaction system is heated to a separation temperature of 100°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C2.

[0091] Catalyst preparation method Example 3: Select low-carbon metal alkoxide magnesium propoxide as the low-carbon metal substance participating in the reaction, and phenol as the aromatic alcohol participating in the reaction. First, magnesium propoxide and phenol are obtained according to a specific ratio of n (magnesium propoxide): n (phenol) = 1: 2.5, and the obtained magnesium propoxide and phenol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, benzene is added to the reactor as an organic entrainer, wherein n (magnesium propoxide): n (benzene) = 1: 3, to obtain a new reaction system. The reaction system is then heated to a reaction temperature of 100°C and maintained for a specific reaction time of 5 hours. During the reaction, an appropriate amount of hydroxyethylethylenediamine is added dropwise as an auxiliary agent, wherein n (magnesium propoxide): n (hydroxyethylethylenediamine) = 1: 0.3. Finally, the reaction system is heated to a separation temperature of 120°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C3.

[0092] Catalyst preparation method Example 4: Select low-carbon metal alkoxide zinc isopropoxide as the low-carbon metal substance participating in the reaction, and bromophenol as the aromatic alcohol participating in the reaction. First, zinc isopropoxide and bromophenol are obtained according to a specific ratio of n (zinc isopropoxide): n (bromophenol) = 1: 3, and the obtained zinc isopropoxide and bromophenol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, methanol is added to the reactor as an organic entrainer, wherein n (zinc isopropoxide): n (methanol) = 1: 4, to obtain a new reaction system. The reaction system is then heated to a reaction temperature of 120°C and maintained for a specific reaction time of 6 hours. During the reaction, an appropriate amount of methyldiethanolamine is added dropwise as an auxiliary agent, wherein n (zinc isopropoxide): n (methyldiethanolamine) = 1: 0.4. Finally, the reaction system is heated to a separation temperature of 140°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C4.

[0093] Catalyst preparation method Example 5: A low-carbon metal alkoxide aluminum tert-butoxide is selected as the low-carbon metal substance participating in the reaction, and p-nitrophenol is selected as the aromatic alcohol participating in the reaction. First, aluminum tert-butoxide and p-nitrophenol are obtained according to a specific ratio of n (aluminum tert-butoxide): n (p-nitrophenol) = 1: 3.5, and the obtained aluminum tert-butoxide and p-nitrophenol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, N, N-dimethylformamide is added to the reactor as an organic entrainer, wherein n (aluminum tert-butoxide): n (N, N-dimethylformamide) = 1: 5, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 110°C and maintained for a specific reaction time of 4 hours. During the reaction, an appropriate amount of triethylamine is added dropwise as an auxiliary agent, wherein n (aluminum tert-butoxide): n (triethylamine) = 1: 0.3. Finally, the reaction system is heated to a separation temperature of 130°C, and the low-carbon alcohol generated by the reaction and the entrainer are evaporated, condensed, and separated. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C5.

[0094] Catalyst preparation method Example 6: Select low-carbon metal alkoxide lithium isobutoxide as the low-carbon metal substance participating in the reaction, and naphthalene methanol as the aromatic alcohol participating in the reaction. First, lithium isobutoxide and naphthalene methanol are obtained according to a specific ratio of n (lithium isobutoxide): n (naphthalene methanol) = 1: 4, and the obtained lithium isobutoxide and naphthalene methanol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, a mixed entrainer of cyclohexane and toluene with a volume ratio of 1: 1 is added to the reactor as an organic entrainer, wherein n (lithium isobutoxide): n (mixed entrainer) = 1: 2.5, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 90°C and maintained for a specific reaction time of 5 hours. During the reaction, an appropriate amount of aniline is added dropwise as an auxiliary agent, wherein n (lithium isobutoxide): n (aniline) = 1: 0.25. Finally, the reaction system is heated to a separation temperature of 110°C, and the low-carbon alcohol generated by the reaction and the entrainer are evaporated, condensed, and separated together. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C6.

[0095] Catalyst preparation method Example 7: Select low-carbon metal alkoxide sodium ethoxide as the low-carbon metal substance participating in the reaction, and indole methanol as the aromatic alcohol participating in the reaction. First, sodium ethoxide and indole methanol are obtained according to a specific ratio of n (sodium ethoxide): n (indole methanol) = 1: 2.2, and the obtained sodium ethoxide and indole methanol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, cyclohexane is added to the reactor as an organic entrainer, wherein n (sodium ethoxide): n (cyclohexane) = 1: 1.5, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 70°C and maintained for a specific reaction time of 4.5 hours. During the reaction, an appropriate amount of diisopropanolamine is added dropwise as an auxiliary agent, wherein n (sodium ethoxide): n (diisopropanolamine) = 1: 0.2. Finally, the reaction system is heated to a separation temperature of 100°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C7.

[0096] Catalyst preparation method Example 8: Select low-carbon metal alkoxide potassium propoxide as the low-carbon metal substance participating in the reaction, and quinoline methanol as the aromatic alcohol participating in the reaction. First, potassium propoxide and quinoline methanol are obtained according to a specific ratio of n (potassium propoxide): n (quinoline methanol) = 1: 2.8, and the obtained potassium propoxide and quinoline methanol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, toluene is added to the reactor as an organic entrainer, wherein n (potassium propoxide): n (toluene) = 1: 2.2, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 85°C and maintained for a specific reaction time of 5.5 hours. During the reaction, an appropriate amount of N-methyldiethanolamine is added dropwise as an auxiliary agent, wherein n (potassium propoxide): n (N-methyldiethanolamine) = 1: 0.3. Finally, the reaction system is heated to a separation temperature of 120°C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C8.

[0097] Catalyst preparation method Example 9: Select low-carbon metal alkoxide magnesium isopropoxide as the low-carbon metal substance participating in the reaction, and phenanthrenol as the aromatic alcohol participating in the reaction. First, magnesium isopropoxide and phenanthrenol are obtained according to a specific ratio of n (magnesium isopropoxide): n (phenanthrenol) = 1: 3.2, and the obtained magnesium isopropoxide and phenanthrenol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, benzene is added to the reactor as an organic entrainer, wherein n (magnesium isopropoxide): n (benzene) = 1: 3.5, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 105 ° C and maintained for a specific reaction time of 6 hours. During the reaction, an appropriate amount of ethanolamine is added dropwise as an auxiliary agent, wherein n (magnesium isopropoxide): n (ethanolamine) = 1: 0.25. Finally, the reaction system is heated to a separation temperature of 135 ° C, and the low-carbon alcohol generated by the reaction is evaporated, condensed, and separated together with the entrainer. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C9.

[0098] Catalyst preparation method Example 10: Select low-carbon metal alkoxide lithium tert-butoxide as the low-carbon metal substance participating in the reaction, and naphthol as the aromatic alcohol participating in the reaction. First, lithium tert-butoxide and naphthol are obtained according to a specific ratio of n (lithium tert-butoxide): n (naphthol) = 1: 3.8, and the obtained lithium tert-butoxide and naphthol are added to the reactor and stirred evenly to obtain a reaction system. Afterwards, N, N-dimethylformamide is added to the reactor as an organic entrainer, wherein n (lithium tert-butoxide): n (N, N-dimethylformamide) = 1: 4.5, to obtain a new reaction system. Afterwards, the reaction system is heated to a reaction temperature of 115°C and maintained for a specific reaction time of 5 hours. During the reaction, an appropriate amount of triethylamine is added dropwise as an auxiliary agent, wherein n (lithium tert-butoxide): n (triethylamine) = 1: 0.35. Finally, the reaction system is heated to a separation temperature of 145°C, and the low-carbon alcohol generated by the reaction and the entrainer are evaporated, condensed, and separated together. When no more distillate is evaporated, the separation is completed, and the remaining substance in the reactor is the target catalyst, which is named C10.

[0099] Catalyst preparation method example 11: The catalyst C1 prepared in catalyst preparation method example 1 was placed at room temperature for 20 days to obtain a new catalyst C1-20.

[0100] Comparative Example 1: Diethylene glycol monobutyl ether sodium salt was used as a catalyst, and the catalyst was named D1.

[0101] Comparative Example 2: Diethylene glycol monobutyl ether sodium salt was used as a catalyst, and the catalyst was named D2.

[0102] Comparative Example 3: A copper catalyst was used as a catalyst, and the catalyst was named D3.

[0103] Comparative Example 4: The difference from Example 1 of the catalyst preparation method is that no auxiliary agent ethanolamine is added during the preparation process. The catalyst is named D4.

[0104] Comparative Example 5: The catalyst D4 prepared in Comparative Example 4 was placed at room temperature for 20 days to obtain a new catalyst D4-20.

[0105] The catalysts prepared by the various types of substances, upper and lower limits of temperature, and interval values ​​involved in this application can all achieve the technical effects of this application, and are not listed one by one here.

[0106] In order to verify the effect of the technical solution of the present application, the prepared catalyst was used to prepare tetraethyl orthosilicate, and the prepared catalyst was evaluated by analyzing the purity of the tetraethyl orthosilicate product and the conversion rate of the silicon powder involved in the reaction in different experiments.

[0107] Among them, gas chromatography analysis was used to calculate the purity of the ethyl orthosilicate product. The specific test conditions were: using an HP-5 chromatographic column, an injection port temperature of 70°C, a column temperature program of initially maintaining 70°C for 2 minutes, heating to 150°C at 30°C / min and maintaining for 17 minutes, a FID detector (Flame Ionization Detector) temperature of 180°C, automatic injection, an injection volume of 1μL, and using the area normalization method to calculate the gas chromatography data to obtain the purity of ethyl silicate. The purity calculation formula for ethyl silicate is as follows:

[0108]

[0109] The calculation formula for the conversion rate of silicon powder involved in the reaction is:

[0110]

[0111] Table 1 is a summary table of evaluation results of the examples and comparative examples provided in the present application. As shown in Table 1, the substances added in different experiments are the same except for the catalyst.

[0112] Table 1 Summary of evaluation results of examples and comparative examples

[0113]

[0114] As can be seen from Table 1, in Examples 1 to 11, the purity of the prepared ethyl orthosilicate all reached a high level, with the highest purity being 99.5% and the lowest purity being 98.3%. In contrast, in Comparative Examples 1 to 5, the purity of the prepared ethyl orthosilicate was relatively low, with the highest purity being only 85%. This shows that when the catalyst proposed in this application is used to prepare ethyl orthosilicate, the purity of the ethyl orthosilicate product can be significantly improved. Further, in Examples 1 to 11, the highest silicon powder conversion rate reached 96.5%, and the lowest silicon powder conversion rate was 93.8%. In contrast, in Comparative Examples 1 to 5, the highest silicon powder conversion rate was 76%. This shows that silicon powder has been fully utilized in the preparation method of ethyl orthosilicate proposed in this application. This is because the catalyst used in Examples 1 to 11 has a strong activity, which not only promotes the main reaction, but also effectively reduces the generation of side reactions, thereby ensuring the efficient utilization of silicon powder and the high-purity preparation of ethyl orthosilicate.

[0115] The silicon powder conversion rate of Example 1 is 96%, and the silicon powder conversion rate of Example 11 is 95.2%, a year-on-year decrease of 0.8%; the silicon powder conversion rate of Example 4 is 76%, and the silicon powder conversion rate of Example 5 is 85%, a year-on-year decrease of 39.4%. Compared with the comparative example, the silicon powder conversion rate decreased by 39.4%, and the silicon powder conversion rate of Example 1 did not decrease significantly. It shows that the activity of the catalyst prepared in this application did not decrease significantly after being placed for 20 days, and it has the characteristics of not being easy to deactivate. At the same time, the purity of tetraethyl orthosilicate in Example 11 is 98.4%, and the purity of tetraethyl orthosilicate in Example 5 is 84.5%. After the catalyst prepared in this application is placed for 20 days, it still maintains a high activity and has the characteristics of high activity. The catalyst prepared in the embodiment of this application has the characteristics of low cost, not easy to deactivate and high activity.

[0116] The silicon powder conversion rate of Example 1 is 96%, and the silicon powder conversion rate of Comparative Example 4 is 76%. The silicon powder conversion rate of Example 1 is 20% different from that of Comparative Example 4. This indicates that when preparing a catalyst, adding an auxiliary agent can improve the activity of the catalyst, so that the utilization rate of silicon powder can be improved when used as a catalyst for tetraethyl orthosilicate.

[0117] In summary, the catalyst prepared by the present invention has the characteristics of long service life and good catalytic activity, and performs well as a catalyst in the preparation of ethyl silicate by the silicon powder method, so that the silicon powder conversion rate is greater than 93% and the purity is more than 98%.

[0118] In addition, the catalyst provided in the present application is also easy to separate from ethyl orthosilicate, which simplifies the separation process in the preparation method of ethyl orthosilicate, reduces production costs, and further improves the purity of the ethyl orthosilicate product after separation.

[0119] The catalyst provided in the embodiments of the present application has at least the following advantages:

[0120] 1. Not easy to deactivate: By adding additives during the preparation of the catalyst, hydrolysis and oxidation can be effectively prevented, the life of the catalyst can be significantly extended, and the preparation cost of the catalyst can be reduced.

[0121] 2. Unique structure: The catalyst has an aromatic hydrocarbon structure, that is, a ring structure; it can improve the catalytic effect to a certain extent.

[0122] 3. Various preparation methods: The catalyst can be prepared from low-carbon metal substances and aromatic alcohols under various conditions. The preparation methods are diverse, and the conditions required for the preparation are mild and simple, which is suitable for large-scale industrial production.

[0123] At the same time, the catalyst of the present application also has the following advantages when used in the preparation of tetraethyl orthosilicate:

[0124] 1. Good catalytic effect: The catalyst is a homogeneous catalyst with the characteristic of free diffusion in the solvent, which can increase the contact opportunity between the active sites and the reactants, greatly improve the reaction rate, shorten the reaction time, and show a good catalytic effect. The conversion rate of silicon powder reaches more than 93%.

[0125] 2. Easy to separate: The boiling point of the catalyst is very different from that of the ethyl orthosilicate product, which makes the separation process of ethyl orthosilicate simple and quick.

[0126] 3. Good product selectivity: It can effectively improve the product selectivity of the reaction during the preparation of tetraethyl orthosilicate, reduce the generation of by-products, and the purity of the generated tetraethyl orthosilicate reaches more than 98%.

[0127] Those skilled in the art should understand that the test data results provided in this application can only be used as a reference and cannot completely limit or ensure that the reproduced experimental results will be completely consistent with them. The reproducibility of experimental results may be affected by many factors, including experimental conditions, operating techniques, and slight changes in the external environment.

[0128] The above embodiments are only for expressing the implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, without departing from the concept of the present application, several variations, equivalent substitutions, improvements, etc. may be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0129] The implementation modes of the present application are described in detail above; however, the present application is not limited to the specific details in the above implementation modes. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0130] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present application will not further describe various possible combinations. In addition, the various different embodiments of the present application can also be combined arbitrarily, as long as they do not violate the idea of ​​the present application, they should also be regarded as the contents disclosed in the present application.

[0131] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a catalyst, characterized in that: include: Adding a low-carbon metal substance and an aromatic alcohol into a reaction kettle in a specific ratio and stirring them evenly to obtain a reaction system, wherein the low-carbon metal substance includes a low-carbon metal alkoxide, a low-carbon metal element or a low-carbon metal hydroxide; The reaction system is heated to a reaction temperature and maintained for a specific reaction time; During the reaction, add an appropriate amount of auxiliary agent; The reaction system is heated to a separation temperature, and the low-carbon alcohol is evaporated to obtain the catalyst.

2. The method according to claim 1, characterized in that The low-carbon metal alkoxide is a metal alkoxide having a carbon number not exceeding 4 in its molecular formula.

3. The method according to claim 2, characterized in that The metal alkoxide includes a combination of one or more of a metal methoxide, a metal ethoxide, a metal propoxide, a metal isopropoxide, a metal tert-butoxide and a metal isobutoxide.

4. The method according to any one of claims 1 to 3, characterized in that The aromatic alcohol includes one or more combinations of benzyl alcohol, phenol, phenylethyl alcohol, bromophenol, p-nitrophenol, naphthalene methanol, indole methanol, indole ethanol, quinoline methanol, phenanthrenol and naphthol.

5. The method according to any one of claims 1 to 3, characterized in that When the low-carbon metal substance is a low-carbon metal alkoxide, the specific ratio is a mass ratio of the low-carbon metal alkoxide to the aromatic alcohol of n (low-carbon metal alkoxide): n (aromatic alcohol) = 1: (1-6).

6. The method according to any one of claims 1 to 3, characterized in that The auxiliary agent comprises a combination of one or more substances selected from ethanolamine, diethanolamine, hydroxyethylethylenediamine, methyldiethanolamine, triethylamine, aniline, diisopropanolamine and N-methyldiethanolamine; And / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the amount of the additive added to the mass of the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (auxiliary agent) = 1: (0.1-0.5).

7. The method according to any one of claims 1 to 3, characterized in that Before the reaction system is heated to the separation temperature, the step further comprises: adding an organic entrainer to the reaction system to obtain a new reaction system; Correspondingly, the step of heating the reaction system to a separation temperature, distilling off the low-carbon alcohol, and obtaining the catalyst comprises: heating a new reaction system to a separation temperature, distilling off the low-carbon alcohol and the organic entrainer, and obtaining the catalyst.

8. The method according to claim 7, characterized in that The organic entrainer comprises one or a combination of two substances selected from cyclohexane, toluene, benzene, methanol and N,N-dimethylformamide; And / or, when the low-carbon metal substance is a low-carbon metal alkoxide, the mass ratio of the organic entrainer to the low-carbon metal alkoxide is n (low-carbon metal alkoxide): n (organic entrainer) = 1: (1-5).

9. The method according to any one of claims 1 to 3, characterized in that Also meets at least one of the following: The reaction temperature ranges from 30°C to 150°C; The reaction time ranges from 2 hours to 8 hours; The separation temperature ranges from 60°C to 300°C.

10. A method for preparing ethyl orthosilicate, characterized in that: include: Add silicon powder, organic solvent and catalyst into a reaction kettle, stir evenly and raise the system to reaction temperature, wherein the catalyst is prepared by the method according to any one of claims 1 to 9; Anhydrous ethanol was added dropwise into the reaction kettle until no hydrogen was generated in the system, and the reaction was completed; The system is heated to the evaporation temperature until the ethyl orthosilicate is evaporated to obtain ethyl orthosilicate.

11. The method according to claim 10, characterized in that Also meets at least one of the following: The added mass ratio of silicon powder, organic solvent and catalyst is m (silicon powder): m (organic solvent): m (catalyst) = 1: 1.2: 0.2; The organic solvent includes one or more of cyclohexane, benzene, toluene, methyl formate, and dimethyl carbonate; The reaction temperature ranges from 110°C to 180°C; The evaporation temperature ranges from 195°C to 200°C.

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