A continuous catalytic cracking apparatus and method for high-boiling organosilicon compounds

Abstract

This invention provides a continuous catalytic cracking apparatus and method for high-boiling-point organosilicon compounds. The continuous catalytic cracking apparatus includes a gas supply unit, a feed unit, a fixed-bed reaction unit, and a cooling unit connected in sequence. The fixed-bed reaction unit includes a fixed-bed reactor. The gas supply unit includes a hydrogen supply pipeline and a nitrogen supply pipeline; the hydrogen supply pipeline is directly connected to the fixed-bed reaction unit. The feed unit includes a raw material storage device, which is nitrogen-sealed via a nitrogen supply pipeline before being connected to the fixed-bed reaction unit. This invention enables continuous production, high stability, and scalable operation, achieving high-value utilization of low-value high-boiling-point organosilicon compounds, reducing environmental pollution, lowering hazardous waste treatment costs, and improving economic efficiency, thus promoting the green and sustainable development of the organosilicon industry.

Description

Technical Field

[0001] This invention relates to the field of organosilicon monomer production technology, and in particular to a continuous catalytic cracking apparatus and method for high-boiling organosilicon compounds. Background Technology

[0002] Organosilicon is an important chemical intermediate, often referred to as "industrial MSG," and is a key indicator of a country's organosilicon industry development. Organosilicon products include silicone oil, silicone rubber, silicone resin, and silane coupling agents, widely used in construction, electronics, medical, and new energy industries. Currently, organosilicon monomers are mainly produced via the "direct method." In this process, in addition to the main product dimethyldichlorosilane (M2), byproducts often include methyltrichlorosilane (M1), trimethylchlorosilane (M3), and high-boiling-point organosilicon compounds.

[0003] Organosilicon high-boiling-point compounds account for 8-10% of the total production of chlorosilane monomers. They are mainly composed of substances containing Si-Si, Si-CH2-Si, Si-O-Si, and Si-Si-Si bonds, with the Si-Si components primarily consisting of MeSiCl2-SiCl2Me and MeSiCl2-SiClMe2. These organosilicon high-boiling-point compounds are complex in composition and undergo hydrolysis upon contact with air and water, producing hydrogen chloride and silicone oil, along with a pungent odor, posing a serious threat to the environment. Furthermore, they are highly corrosive, requiring high-quality storage materials. With the annual expansion of organosilicon production capacity, the large-scale accumulation of organosilicon chlorosilanes has increased the hazardous waste treatment costs for enterprises, creating significant environmental safety hazards and gradually becoming an obstacle to the development of the organosilicon industry.

[0004] Currently, several studies have reported methods for preparing methylchlorosilane monomers by cracking high-boiling-point substances, such as US2681355A, US5430168A, US2709176A, US5288892A, US5877337, and US5326896A. The most commonly used catalyst is tri-n-butylamine, but tri-n-butylamine is a highly toxic chemical and does not meet the requirements of green chemistry. Furthermore, the most commonly used reaction processes are batch or semi-continuous reactor processes, which suffer from problems such as the inability to produce continuously, difficulty in separation during homogeneous catalysis, high levels of hazardous waste, and poor selectivity for the target product.

[0005] Therefore, there is a need to develop new processes and devices for treating high-boiling-point organosilicon compounds. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a continuous catalytic cracking device and method for organosilicon high-boiling-point compounds, solving the problems of difficulty in continuous production, low resource utilization, and large hazardous waste generation associated with existing methods using tri-n-butylamine as a catalyst. The method provided by this invention recycles and utilizes organosilicon high-boiling-point compounds, realizing waste resource utilization, increasing the yield of dimethyldichlorosilane, reducing hazardous waste treatment costs, increasing silicon resource utilization efficiency, and reducing the environmental pollution and harm caused by organosilicon high-boiling-point compounds, thus achieving the goals of cost reduction, efficiency improvement, and enhanced economic benefits.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a continuous catalytic cracking apparatus for high-boiling-point organosilicon compounds. The continuous catalytic cracking apparatus includes a gas supply unit, a feed unit, a fixed-bed reaction unit, and a cooling unit connected in sequence. The fixed-bed reaction unit includes a fixed-bed reactor. The gas supply unit includes a hydrogen supply pipeline and a nitrogen supply pipeline. The hydrogen supply pipeline is directly connected to the fixed-bed reaction unit. The feed unit includes a raw liquid storage device, which is nitrogen-sealed via a nitrogen supply pipeline before being connected to the fixed-bed reaction unit.

[0009] This invention develops a device capable of continuous catalytic cracking of high-boiling-point organosilicon compounds, which can catalytically convert high-boiling-point organosilicon compounds into high-value monosilanes. Compared with a reaction vessel, it has the following advantages: First, relying on a solid-phase catalyst, it can directly achieve online separation of reactants and catalysts, thus realizing continuous cracking reaction; second, it does not require the use of toxic amine-containing catalysts, making it more environmentally friendly; and third, this process can facilitate the complete conversion of high-boiling-point organosilicon compounds, improve the selectivity of dimethyldichlorosilane, and increase production efficiency.

[0010] Preferably, the feeding unit further includes a material conveying device, which is connected to the raw liquid storage device and the fixed bed reaction unit respectively.

[0011] Preferably, the feeding unit further includes a metering device located at the bottom of the raw material storage device, and a nitrogen sealing device located inside the raw material storage device. The nitrogen sealing device prevents air from entering the storage tank by controlling the nitrogen sealing pressure. The metering device is preferably a large-range, high-precision balance to accurately control the feed rate.

[0012] Preferably, the stock solution storage device is provided with at least two vents for setting up a nitrogen sealing device.

[0013] Preferably, the internal material of the stock solution storage device includes Hastelloy and / or 316L stainless steel.

[0014] Preferably, the stock solution storage device has a storage inlet at the top and a storage outlet at the bottom, and a ball valve is installed at the storage outlet. The ball valve is connected to the metering device.

[0015] Preferably, the nitrogen supply pipeline and the hydrogen supply pipeline are each independently equipped with a check valve, a flow controller, a pressure gauge, and a safety valve. The check valve is used to prevent backflow of gas or material in the reactor. The safety valve is installed according to safety regulations; it is used for emergency venting when the reaction pipeline is blocked and substances cannot be discharged from the system, preventing overpressure and ensuring safety.

[0016] Preferably, the fixed-bed reactor includes a first reaction outlet and a second reaction outlet.

[0017] Preferably, the first reaction outlet is connected to the inlet of the cooling unit.

[0018] Preferably, the fixed-bed reactor has a reactant inlet at the top and a reactant outlet at the bottom.

[0019] Preferably, the fixed-bed reactor is equipped with a pressure relief valve.

[0020] Preferably, the fixed-bed reaction unit further includes a preheating mixer disposed before the fixed-bed reactor.

[0021] Preferably, the cooling unit includes a cooler and a recovery device connected in sequence. The cooler of the present invention employs a circulating cooling device to ensure that the cooling tank is maintained at -15°C to -2°C, rapidly condensing the gaseous products into a liquid state.

[0022] Preferably, the outlet of the cooler includes a first cooling outlet connected to the inlet of the recovery device and a second cooling outlet for venting.

[0023] Preferably, the second cooling outlet is connected to an air vent.

[0024] Generally, in the pilot and laboratory stages of this invention, the continuous catalytic cracking device preferably further includes an online analysis unit. During actual industrial operation, commonly used industrial testing instruments can be used for analysis, or sampling points can be designed for analysis.

[0025] Preferably, the second reaction outlet is connected to the online analysis unit.

[0026] Preferably, the online analysis unit includes a six-way valve, a heat preservation device, and a gas chromatography analysis device.

[0027] Preferably, the online analysis unit is equipped with a vent. This is used for emergency venting when the reaction pipeline is blocked and substances in the system cannot be discharged, preventing system overpressure and ensuring safety.

[0028] In a second aspect, the present invention provides a continuous catalytic cracking method for high-boiling-point organosilicon compounds, wherein the continuous catalytic cracking method is carried out using the continuous catalytic cracking apparatus for high-boiling-point organosilicon compounds described in the first aspect.

[0029] As a preferred technical solution of the present invention, the continuous catalytic cracking method includes: passing organosilicon high-boiling liquid and hydrogen into a fixed-bed reactor filled with catalyst to carry out a continuous catalytic cracking reaction, and sending the reactants into a cooling unit for cooling to obtain the cracked products.

[0030] The present invention can continuously operate the catalytic cracking reaction of organosilicon high-boiling substances, realize the high-value utilization of waste, generate dimethyldichlorosilane, and achieve the purpose of reducing costs and increasing efficiency, reducing pollution and improving economic benefits.

[0031] Preferably, the raw material storage device and the fixed-bed reactor are first purged with nitrogen, and then the high-boiling-point organosilicon raw material and hydrogen are introduced into the fixed-bed reactor filled with catalyst.

[0032] This invention preferably employs nitrogen purging before the fixed-bed pyrolysis reaction to prevent air and water residue. This results in a better final reaction outcome, and the subsequent cooling unit significantly improves the conversion rate and selectivity of the reaction.

[0033] In this invention, the high-boiling-point organic silicon concentrate can be filtered, distilled, or rotary evaporated to remove solid residues and high-boiling-point impurities. High-boiling-point concentrates often contain small amounts of copper catalyst residues, hydrolysis products, and other solid substances. Without treatment, these can clog pumps or catalyst beds, causing feed rate fluctuations, pump damage, system pressure fluctuations, and even overpressure. Therefore, removing these solid residues ensures stable system operation and extends start-up cycles.

[0034] Preferably, the original stock solution of the organosilicon high-boiling-point substance includes, but is not limited to, any one or at least two combinations of high-boiling-point substances from a heavy separation tower, high-boiling-point substances from a heavy refining tower, or slurry supernatant. Typical but non-limiting combinations include the combination of high-boiling-point substances from a heavy separation tower and high-boiling-point substances from a heavy refining tower, the combination of slurry supernatant and high-boiling-point substances from a heavy refining tower, and the combination of high-boiling-point substances from a heavy separation tower and slurry supernatant.

[0035] Preferably, the organic matter in the organosilicon high-boiling solution has any one or a combination of at least two of the following: Si-Si groups, Si-CH2-Si groups, Si-O-Si groups, or Si-Si-Si groups. Typical but non-limiting combinations are combinations of Si-Si groups and Si-CH2-Si groups, combinations of Si-Si-Si groups and Si-CH2-Si groups, and combinations of Si-Si groups and Si-Si-Si groups.

[0036] Preferably, the content of Si-Si components in the high-boiling-point organosilicon stock solution is greater than 50 wt%, for example, it can be 50 wt%, 52 wt%, 53 wt%, 55 wt%, 58 wt%, 60 wt%, 62 wt%, 63 wt%, 65 wt%, 68 wt%, 70 wt%, 72 wt%, or 75 wt%.

[0037] Preferably, the Si-Si component in the organosilicon high-boiling-point stock solution includes any one or a combination of at least two of MeSiCl2-SiCl2Me, MeSiCl2-SiClMe2, or Me2SiCl-SiClMe2, wherein typical but non-limiting combinations are combinations of MeSiCl2-SiCl2Me and MeSiCl2-SiClMe2, combinations of Me2SiCl-SiClMe2 and MeSiCl2-SiClMe2, and combinations of MeSiCl2-SiCl2Me and Me2SiCl-SiClMe2.

[0038] Preferably, the organosilicon high-boiling-point stock solution contains a monosilane component, which includes any one or a combination of at least two of dimethyldichlorosilane, methyltrichlorosilane, trimethylchlorosilane, or methyldichlorosilane. Typical but non-limiting combinations are the combination of dimethyldichlorosilane and methyltrichlorosilane, the combination of trimethylchlorosilane and methyltrichlorosilane, the combination of dimethyldichlorosilane and trimethylchlorosilane, and the combination of dimethyldichlorosilane and methyldichlorosilane.

[0039] Preferably, the content of monosilane component in the organosilicon high-boiling-point stock solution is 10-30 wt%, for example, it can be 10 wt%, 13 wt%, 15 wt%, 17 wt%, 19 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, or 30 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0040] Preferably, the catalyst comprises any one or a combination of at least two of silicon-aluminum compounds, aluminum-based compounds, metal oxides, or elemental metals, wherein typical but non-limiting combinations are combinations of silicon-aluminum compounds and aluminum-based compounds, combinations of metal oxides and aluminum-based compounds, combinations of silicon-aluminum compounds and metal oxides, and combinations of elemental metals and aluminum-based compounds.

[0041] Preferably, the silicon-aluminum compound is a molecular sieve.

[0042] Preferably, the silicon-aluminum molar ratio (SiO2 / Al2O3) in the silicon-aluminum compound is 50–200:1, for example, it can be 50:1, 67:1, 84:1, 100:1, 117:1, 134:1, 150:1, 167:1, 184:1, or 200:1, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. Molecular sieves are a common and readily available catalyst support, inherently acidic, and possess a certain catalytic ability. Loading various components onto molecular sieves can effectively improve catalytic performance and provide a certain strength, which is beneficial for industrial applications.

[0043] Preferably, the aluminum-based compound comprises any one or a combination of at least two of AlCl3, Al2O3, NaAlCl4, or KAlCl4, wherein typical but non-limiting combinations are combinations of AlCl3 and Al2O3, NaAlCl4 and Al2O3, AlCl3 and NaAlCl4, KAlCl4 and Al2O3, and AlCl3 and KAlCl4. Aluminum-based compounds possess Lewis acidity and can catalyze the breaking of Si-Si bonds in high-boiling organosilicon compounds, thus promoting the conversion of high-boiling organosilicon compounds into chlorosilane monomers. Furthermore, AlCl3 can promote the disproportionation rearrangement of functional groups in methyltrichlorosilane and trimethylchlorosilane to generate dimethyldichlorosilane, significantly increasing the proportion of dimethyldichlorosilane in the product.

[0044] Preferably, the metal in the metal oxide or elemental metal independently comprises any one or at least two combinations of Ni, Mo, Fe, Co, Zn, or Cu, wherein typical but non-limiting combinations are combinations of Ni and Mo, Fe and Mo, Ni and Fe, Co and Zn, Ni and Co, and Cu and Mo. These metals can be loaded onto a silica-alumina molecular sieve to form multifunctional active sites. On one hand, these sites can promote the dissociation of hydrogen, thereby promoting the hydrocracking of high-boiling-point organosilicon compounds. On the other hand, these sites can also promote the disproportionation of chlorosilanes, improving the selectivity of dimethyldichlorosilane.

[0045] Preferably, the temperature of the continuous catalytic cracking reaction is 200–500°C, for example, 200°C, 210°C, 220°C, 250°C, 280°C, 300°C, 323°C, 345°C, 367°C, 389°C, 412°C, 434°C, 456°C, 478°C, or 500°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Preferably, the pressure of the continuous catalytic cracking reaction is 0.1 to 2.0 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.5 MPa, 0.7 MPa, 0.9 MPa, 1 MPa, 1.2 MPa, 1.4 MPa, 1.5 MPa, 1.7 MPa, 1.9 MPa or 2.0 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] The pressure mentioned in this invention refers to hydrogen pressure. Increasing the hydrogen pressure can increase the hydrogen concentration in the fixed bed, enhance the degree of hydrogen dissociation, and promote the forward cracking reaction of organosilicon high-boiling-point compounds. However, excessively increasing the hydrogen flow rate will reduce the residence time of the raw liquid in the bed. Therefore, selecting appropriate hydrogen pressure and hydrogen flow rate is beneficial to the complete conversion of organosilicon high-boiling-point compounds, improves the selectivity of dimethyldichlorosilane, and improves production efficiency.

[0048] Preferably, the hydrogen flow rate of the continuous catalytic cracking reaction is 50 to 400 mL / min, for example, it can be 50 mL / min, 89 mL / min, 128 mL / min, 167 mL / min, 206 mL / min, 245 mL / min, 284 mL / min, 323 mL / min, 362 mL / min or 400 mL / min, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0049] Preferably, the feed liquid hourly space velocity (LHSV) of the organosilicon high-boiling-point stock solution is 0.01–10 h⁻¹. -1 For example, it could be 0.01h -1 0.02h -1 0.05h -1 0.08h -1 0.1h -1 0.5h -1 1.0h -1 2.0h -1 5.0h -1 6.8h -1 8.1h -1 9.4h -1 or 10h -1 This includes, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0050] In this invention, the feed rate of high-boiling-point substances affects the weight hourly space velocity of the reaction. Setting an appropriate feed rate is beneficial to the conversion of high-boiling-point substances.

[0051] Preferably, the cooling temperature is -15℃ to -2℃, for example, it can be -15℃, -10℃, -8℃, -7℃, -6.5℃, -6℃, -5.5℃, -5℃, -4.5℃, -4℃, -3.5℃, -3℃, -2.5℃ or -2℃, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0052] Preferably, the high-boiling-point organosilicon stock solution and hydrogen are first passed into a preheating mixer for preheating and mixing, and then the mixed stream is passed into a fixed-bed reactor.

[0053] Preferably, the preheating temperature is 300-400℃, for example, it can be 300℃, 310℃, 320℃, 323℃, 330℃, 345℃, 350℃, 367℃, 389℃, 390℃, 395℃ or 400℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0054] Preferably, during the continuous catalytic cracking reaction and cooling process, the reactants are fed into an online analysis unit for simultaneous detection and analysis of their composition.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects:

[0056] (1) The continuous catalytic cracking device for high-boiling-point organosilicon provided by the present invention realizes the recycling of high-boiling-point organosilicon, reducing the safety hazards and environmental risks caused by long-term large-scale accumulation of high-boiling-point organosilicon.

[0057] (2) The continuous catalytic cracking method for high-boiling organosilicon compounds provided by the present invention is simple and easy to operate. The fixed-bed catalytic process can achieve continuous production and can be continuously operated for more than 3 months. It reduces the problems of the original batch cracking process, such as difficulty in determining the reaction endpoint, low conversion rate, and inability to produce continuously. It is suitable for large-scale promotion and utilization.

[0058] (3) The continuous catalytic cracking method for high-boiling organosilicon compounds provided by the present invention can use green catalysts instead of highly toxic tri-n-butylamine catalysts, thereby achieving source control of environmental hazards and conforming to the principles of green chemistry. At the same time, it reduces the problem of material separation caused by homogeneous reactions, reduces the generation of hazardous waste, improves product quality, and can increase economic benefits.

[0059] (4) The continuous catalytic cracking method for high-boiling-point organosilicon provided by the present invention achieves a conversion rate of over 90% under preferred conditions, and the final product exhibits a selectivity of over 90% for chlorosilane monomers, with a selectivity of over 60% for dimethyldichlorosilane. This process increases the utilization rate of silicon resources and improves silicon atom economy. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the continuous catalytic cracking device for high-boiling organosilicon compounds provided in Embodiment 1 of the present invention.

[0061] In the diagram: 1. Gas supply unit; 11. Hydrogen supply pipeline; 12. Nitrogen supply pipeline; 2. Feeding unit; 21. Raw material storage device; 22. Material conveying device; 3. Fixed bed reaction unit; 31. Fixed bed reactor; 4. Cooling unit; 41. Cooler; 42. Recovery device; 5. Online analysis unit; 51. Gas chromatography analysis device. Detailed Implementation

[0062] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0063] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0064] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving complete process, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0066] Example 1

[0067] This embodiment provides a continuous catalytic cracking device for high-boiling-point organosilicon compounds. (See also...) Figure 1 The continuous catalytic cracking device includes a gas supply unit 1, a feed unit 2, a fixed bed reaction unit 3, and a cooling unit 4 connected in sequence.

[0068] The fixed-bed reaction unit 3 includes a fixed-bed reactor 31; the fixed-bed reactor 31 includes a first reaction outlet and a second reaction outlet; the first reaction outlet is connected to the inlet of the cooling unit 4; the top of the fixed-bed reactor 31 is provided with a reactant inlet and the bottom is provided with a reactant outlet; the fixed-bed reaction unit 3 also includes a preheating mixer provided before the fixed-bed reactor 31.

[0069] The cooling unit 4 includes a cooler 41 and a recovery device 42 connected in sequence; the outlet of the cooler 41 includes a first cooling outlet connected to the inlet of the recovery device 42 and a second cooling outlet for venting; the second cooling outlet is connected to an vent. The second reaction outlet is connected to the online analysis unit 5.

[0070] The gas supply unit 1 includes a hydrogen gas supply pipeline 11 and a nitrogen gas supply pipeline 12; the hydrogen gas supply pipeline 11 is directly connected to the fixed bed reaction unit 3.

[0071] The feeding unit 2 includes a raw liquid storage device 21, and the nitrogen supply pipeline 12 first passes through the raw liquid storage device 21 and then connects to the fixed bed reaction unit 3. The feeding unit 2 also includes a material conveying device 22, which is connected to both the raw liquid storage device 21 and the fixed bed reaction unit 3. The feeding unit 2 also includes a metering device located at the lower part of the raw liquid storage device 21, and a nitrogen sealing device located inside the raw liquid storage device 21.

[0072] In the laboratory pilot phase, the continuous catalytic cracking device also includes an online analysis unit 5. The online analysis unit 5 includes a six-way valve, a heat preservation device, and a gas chromatograph 51. The outlet of the online analysis unit 5 is equipped with an air vent.

[0073] In one specific embodiment, the internal material of the stock solution storage device 21 includes Hastelloy and / or 316L stainless steel.

[0074] In one specific embodiment, the stock solution storage device 21 has a storage inlet at the top and a storage outlet at the bottom, and a ball valve is installed at the storage outlet. The ball valve is connected to the metering device.

[0075] In one specific embodiment, the nitrogen supply line 12 and the hydrogen supply line 11 are each independently equipped with a check valve, a flow controller, a pressure gauge and a safety valve.

[0076] In one specific embodiment, the fixed-bed reactor 31 is equipped with a pressure relief valve.

[0077] Example 2

[0078] This embodiment provides a continuous catalytic cracking device for high-boiling organosilicon compounds. Except for the fact that the metering device is not located at the bottom of the raw liquid storage device, the continuous catalytic cracking device is the same as that in Embodiment 1.

[0079] In this embodiment, the lack of a metering device resulted in poor quality control of the feed during the continuous reaction process, leading to significant overall production fluctuations.

[0080] Comparative Example 1

[0081] This comparative example provides a catalytic cracking device for high-boiling organosilicon compounds. The catalytic cracking device is the same as that in Example 1, except that the fixed bed is replaced with a reaction vessel and a stirring device is installed inside.

[0082] Comparative Example 2

[0083] This comparative example provides a catalytic cracking device for high-boiling organosilicon compounds. Except for the nitrogen supply pipeline, which is not directly connected to the fixed-bed reaction unit through the original liquid storage device, the catalytic cracking device is the same as that in Example 1.

[0084] In this comparative example, the raw material storage device was not nitrogen-sealed, which led to problems such as material hydrolysis causing corrosion and leakage of the device.

[0085] The specific composition of the organosilicon high-boiling-point stock solution used in the following application examples and comparative examples is shown in Table 1.

[0086] Table 1

[0087] Components content(%) <![CDATA[(CH3)3SiCl]]> 0.45 <![CDATA[CH3SiCl3]]> 3.51 <![CDATA[(CH3)2SiCl2]]> 8.21 <![CDATA[CH2=CHCH2SiCl2CH3]]> 1.87 <![CDATA[(CH3)3Si-CH2-Si(CH3)3]]> 2.21 <![CDATA[(CH3)3Si-Si(CH3)2Cl]]> 1.21 <![CDATA[(CH3)2ClSi-O-Si(CH3)2Cl]]> 1.53 <![CDATA[(CH3)2ClSi-Si(CH3)2Cl]]> 6.40 <![CDATA[CH3SiCl2-CH2CH2CH3]]> 4.52 <![CDATA[(CH3)3Si-CH2-Si(CH3)2Cl]]> 2.23 <![CDATA[(CH3)2SiCl-SiCH3Cl2]]> 25.68 <![CDATA[CH3SiCl2-SiCH3Cl2]]> 40.31 <![CDATA[(CH3)2ClSi-CH2-Si(CH3)2Cl]]> 1.87

[0088] Application Example 1

[0089] This application example provides a continuous catalytic cracking method for high-boiling-point organosilicon compounds. The continuous catalytic cracking method uses the apparatus provided in Example 1 and specifically includes:

[0090] First, the stock solution storage device (containing high-boiling-point organosilicon stock solution) and the fixed-bed reactor (reaction tube diameter 20 mm) were purged eight times with nitrogen. Then, the feed pump was turned on, and the high-boiling-point organosilicon stock solution and hydrogen were first introduced into a preheating mixer for preheating and mixing at 400℃. The resulting mixed stream was then introduced into the fixed-bed reactor packed with catalyst (5.0 wt% Ni-35% Beta / 60% Al2O3, bed height 25 cm). A continuous catalytic cracking reaction was carried out at 400℃ and 1.2 MPa, with a feed mass hourly space velocity (WHSV) of 1.0 h⁻¹ for the high-boiling-point organosilicon stock solution during the continuous catalytic cracking reaction. -1 The reactants are fed into the cooling unit through a three-way connector, and a large amount of the reactants are cooled to -10°C to obtain the cracked products. During the continuous catalytic cracking reaction and cooling process, a small amount of reactants are sent to the online analysis unit for synchronous detection and analysis of the material composition.

[0091] Application Example 2

[0092] This application example provides a continuous catalytic cracking method for high-boiling-point organosilicon compounds. The continuous catalytic cracking method uses the apparatus provided in Example 1 and specifically includes:

[0093] First, the stock solution storage device (containing organosilicon high-boiling-point stock solution) and the fixed-bed reactor (reaction tube diameter 20 mm) were purged 10 times with nitrogen. Then, the feed pump was turned on, and the organosilicon high-boiling-point stock solution and hydrogen were first introduced into a preheating mixer for preheating and mixing at 300°C. The resulting mixed stream was then introduced into the fixed-bed reactor packed with catalyst (12.2 wt% Ni - 25 wt% Beta / 62.8 wt% Al₂O₃, bed height 20 cm). A continuous catalytic cracking reaction was carried out at 300°C and 2 MPa. The feed mass hourly space velocity (WHSV) of the organosilicon high-boiling-point stock solution in the continuous catalytic cracking reaction was 3.0 h⁻¹. -1 The reactants are fed into the cooling unit through a three-way connector, with a large amount of reactants being cooled to -5°C to obtain the pyrolysis products. During the continuous catalytic pyrolysis reaction and cooling process, trace amounts of reactants are fed into the online analysis unit for simultaneous detection and analysis of the material composition.

[0094] Application Example 3

[0095] This application example provides a continuous catalytic cracking method for high-boiling-point organosilicon compounds. The continuous catalytic cracking method uses the apparatus provided in Example 1 and specifically includes:

[0096] First, the stock solution storage device (containing organosilicon high-boiling-point stock solution) and the fixed-bed reactor (reaction tube diameter 20 mm) were purged five times with nitrogen. Then, the feed pump was turned on, and the organosilicon high-boiling-point stock solution and hydrogen were first introduced into a preheating mixer for preheating and mixing at 500℃. The resulting mixed stream was then introduced into the fixed-bed reactor packed with catalyst (10.6 wt% Co-55 wt% ZSM-5 / 34.4 wt% Al2O3, bed height 20 cm). A continuous catalytic cracking reaction was carried out at 500℃ and 0.8 MPa, with a feed mass hourly space velocity (WHSV) of 8.0 h⁻¹ for the organosilicon high-boiling-point stock solution during the continuous catalytic cracking reaction. -1 The reactants are fed into the cooling unit through a three-way connector, and a large amount of the reactants are cooled to -14°C to obtain the cracked products. During the continuous catalytic cracking reaction and cooling process, trace amounts of reactants are sent to the online analysis unit for simultaneous detection and analysis of the material composition.

[0097] Application Example 4

[0098] This application example provides a continuous catalytic cracking method for high-boiling-point organosilicon compounds. The continuous catalytic cracking method uses the apparatus provided in Example 1 and specifically includes:

[0099] First, the stock solution storage device (containing organosilicon high-boiling-point stock solution) and the fixed-bed reactor (reaction tube diameter 20 mm) were purged seven times with nitrogen. Then, the feed pump was turned on, and the organosilicon high-boiling-point stock solution and hydrogen were first introduced into a preheating mixer for preheating and mixing at 350°C. The resulting mixed stream was then introduced into the fixed-bed reactor packed with catalyst (12.2 wt% Ni - 33 wt% USY / 54.8 wt% Al₂O₃, bed height 20 cm). A continuous catalytic cracking reaction was carried out at 350°C and 0.5 MPa, with a feed mass hourly space velocity (WHSV) of 5.0 h⁻¹ for the organosilicon high-boiling-point stock solution during the continuous catalytic cracking reaction. -1 The reactants are fed into the cooling unit through a three-way connector, and a large amount of the reactants are cooled to -7°C to obtain the cracked products. During the continuous catalytic cracking reaction and cooling process, trace amounts of reactants are sent to the online analysis unit for simultaneous detection and analysis of the material composition.

[0100] Application Example 5

[0101] This application example provides a continuous catalytic cracking method for high-boiling organosilicon compounds. Except for the continuous catalytic cracking reaction temperature of 190°C, the continuous catalytic cracking method is the same as that in Application Example 1, and will not be repeated here.

[0102] Application Example 6

[0103] This application example provides a continuous catalytic cracking method for high-boiling organosilicon compounds. Except for the continuous catalytic cracking reaction temperature of 600°C, the continuous catalytic cracking method is the same as that in Application Example 1, and will not be repeated here.

[0104] Application Example 7

[0105] This application example provides a continuous catalytic cracking method for high-boiling organosilicon compounds. Except for the pressure of the continuous catalytic cracking reaction being 101 kPa, the continuous catalytic cracking method is the same as that in Application Example 1, and will not be repeated here.

[0106] In this application example, the pyrolysis reaction was difficult to carry out normally due to the low pressure of the pyrolysis reaction.

[0107] Application Example 8

[0108] This application example provides a continuous catalytic cracking method for organosilicon high-boiling-point compounds, wherein the feed liquid of the continuous catalytic cracking method has a mass hourly space velocity (MSV) of 12 h⁻¹. -1 Except for the example, the rest are the same as in application example 1, and will not be repeated here.

[0109] Application Example 9 and Comparative Examples 1-2

[0110] Application Example 9 and Comparative Examples 1-2 provide a catalytic cracking method for high-boiling-point organosilicon compounds. Except for using the catalytic cracking apparatus for high-boiling-point organosilicon compounds in Example 2 and Comparative Examples 1-2 respectively, the catalytic cracking method for high-boiling-point organosilicon compounds is the same as that in Application Example 1, and will not be described again here.

[0111] The analysis results of the above application examples and comparative examples are shown in Table 2.

[0112] Table 2

[0113]

[0114]

[0115] In Tables 1 and 2, " / " indicates that there is no relevant data.

[0116] The following points can be observed from Table 2:

[0117] (1) As can be seen from Application Examples 1 to 4, the continuous catalytic cracking method for high-boiling organosilicon compounds provided by the present invention can not only operate continuously, but also achieve a cracking rate of over 90.1% for high-boiling organosilicon compounds, and the selectivity of dimethyldichlorosilane is over 63%.

[0118] (2) Comparing Application Example 1 and Application Examples 5-6, it can be seen that the temperature of the continuous catalytic cracking reaction in Application Example 5 is too low, resulting in a decrease in the conversion rate of organosilicon high-boiling products to 25.3%. In Application Example 6, although the conversion rate of organosilicon high-boiling products is as high as 97.9%, the selectivity of dimethyldichlorosilane is only 30.1%. This shows that the present invention preferably controls the temperature of the cracking reaction in the continuous catalytic cracking reaction, and at the same time has better conversion rate and selectivity of dimethyldichlorosilane.

[0119] (3) Comparing Application Example 1 and Application Examples 7-8, it can be seen that the present invention preferably controls the pressure and mass hourly space velocity of the continuous catalytic cracking reaction within a reasonable range, resulting in better catalytic activity and selectivity for dimethyldichlorosilane.

[0120] (4) Comparing Application Example 1 and Application Comparative Examples 1-2, it can be seen that the reaction vessel used in Application Comparative Example 1 not only cannot be operated continuously, but also the conversion rate of high-boiling organosilicon is only 30.2% and the selectivity is only 65.3%. In Application Comparative Example 2, the equipment was not nitrogen-sealed, and there were problems such as corrosion and leakage caused by hydrolysis of the material.

[0121] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A continuous catalytic cracking method for high-boiling organosilicon compounds, characterized in that, The continuous catalytic cracking method includes: introducing a high-boiling-point organosilicon stock solution and hydrogen gas into a fixed-bed reactor packed with a catalyst to carry out a continuous catalytic cracking reaction; the reactants are then fed into a cooling unit for cooling to obtain the cracked products; the organic matter in the high-boiling-point organosilicon stock solution has Si-CH2-Si groups or Si-Si-Si groups; the catalyst includes an aluminum-based compound; the aluminum-based compound includes NaAlCl4 or KAlCl4. The continuous catalytic cracking method is carried out using a continuous catalytic cracking device; the continuous catalytic cracking device includes a gas supply unit, a feed unit, a fixed-bed reaction unit, and a cooling unit connected in sequence. The fixed-bed reaction unit includes a fixed-bed reactor; The gas supply unit includes a hydrogen supply pipeline and a nitrogen supply pipeline; the hydrogen supply pipeline is directly connected to the fixed bed reaction unit. The feeding unit includes a raw liquid storage device, which is connected to the fixed bed reaction unit after being sealed with nitrogen through a nitrogen supply pipeline; the feeding unit also includes a metering device located at the bottom of the raw liquid storage device, and a nitrogen sealing device located inside the raw liquid storage device.

2. The continuous catalytic cracking method according to claim 1, characterized in that, The feeding unit also includes a material conveying device, which is connected to the raw liquid storage device and the fixed bed reaction unit respectively.

3. The continuous catalytic cracking method according to claim 1, characterized in that, The fixed-bed reactor includes a first reaction outlet and a second reaction outlet.

4. The continuous catalytic cracking method according to claim 3, characterized in that, The first reaction outlet is connected to the inlet of the cooling unit.

5. The continuous catalytic cracking method according to claim 1, characterized in that, The fixed-bed reactor has a reactant inlet at the top and a reactant outlet at the bottom.

6. The continuous catalytic cracking method according to claim 1, characterized in that, The fixed-bed reaction unit also includes a preheating mixer located before the fixed-bed reactor.

7. The continuous catalytic cracking method according to claim 1, characterized in that, The cooling unit includes a cooler and a recovery device connected in sequence.

8. The continuous catalytic cracking method according to claim 7, characterized in that, The cooler outlet includes a first cooling outlet connected to the inlet of the recovery device and a second cooling outlet for venting.

9. The continuous catalytic cracking method according to claim 8, characterized in that, The second cooling outlet is connected to the vent.

10. The continuous catalytic cracking method according to claim 1, characterized in that, The organic matter in the high-boiling-point organic silicon stock solution also contains Si-Si groups or Si-O-Si groups.

11. The continuous catalytic cracking method according to claim 10, wherein the content of Si-Si components in the organosilicon high-boiling solution is greater than 50 wt%.

12. The continuous catalytic cracking method according to claim 11, wherein the Si-Si component in the organosilicon high-boiling-point stock solution includes any one or a combination of at least two of MeSiCl2-SiCl2Me, MeSiCl2-SiClMe2, or Me2SiCl-SiClMe2.

13. The continuous catalytic cracking method according to claim 1, wherein the organosilicon high-boiling-point stock solution contains a monosilane component, wherein the monosilane component includes any one or a combination of at least two of dimethyldichlorosilane, methyltrichlorosilane, trimethylchlorosilane or methyldichlorohydrosilane.

14. In the continuous catalytic cracking method according to claim 13, the content of monosilane component in the organosilicon high-boiling solution is 10~30wt%.

15. The continuous catalytic cracking method according to claim 1, characterized in that, The catalyst also includes any one or a combination of at least two of silicon-aluminum compounds, metal oxides, or elemental metals.

16. The continuous catalytic cracking method according to claim 15, wherein the silicon-aluminum compound is a molecular sieve.

17. The continuous catalytic cracking method according to claim 15, wherein the silicon-aluminum molar ratio SiO2 / Al2O3 in the silicon-aluminum compound is 50~200:

1.

18. The continuous catalytic cracking method according to claim 15, wherein the metal in the metal oxide or elemental metal independently comprises any one or a combination of at least two of Ni, Mo, Fe, Co, Zn or Cu.

19. The continuous catalytic cracking method according to claim 1, characterized in that, The temperature of the continuous catalytic cracking reaction is 200~500℃.

20. The continuous catalytic cracking method according to claim 1, wherein the pressure of the continuous catalytic cracking reaction is 0.1~2.0 MPa.

21. The continuous catalytic cracking method according to claim 1, wherein the feed liquid mass hourly space velocity of the organosilicon high-boiling-point stock solution is 0.01~10 h⁻¹. -1 .

22. The continuous catalytic cracking method according to claim 1, wherein the cooling temperature is -15℃ to -2℃.

23. The continuous catalytic cracking method according to claim 1, characterized in that, The high-boiling-point organosilicon stock solution and hydrogen are first passed into a preheating mixer for preheating and mixing, and then the mixed stream is passed into a fixed-bed reactor.

24. The continuous catalytic cracking method according to claim 23, wherein the preheating temperature is 300~400℃.

25. The continuous catalytic cracking method according to claim 1, characterized in that, During the continuous catalytic cracking reaction and cooling process, the reactants are fed into an online analysis unit for simultaneous detection and analysis of their composition.

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