Co@hz / b catalyst, preparation method and use thereof

Abstract

This invention provides a Co@HZ / B catalyst, its preparation method, and its applications. The preparation method includes the following steps: mixing a Co@HZ precursor and a B support source, followed by sequential molding, drying, calcination, and reduction to obtain the Co@HZ / B catalyst. In the Co@HZ precursor, HZ is a low-silicon-aluminum-ratio hydrogen-type molecular sieve with a silicon-to-aluminum molar ratio (SiO2 / Al2O3) of 5–50:1; and B is an inorganic oxide support. The catalyst provided by this invention exhibits excellent high-boiling-point cracking rate and methylchlorosilane monomer selectivity in organosilicon high-boiling-point cracking reactions, showing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of organosilicon preparation technology, and in particular to a Co@HZ / B catalyst, its preparation method, and its uses. Background Technology

[0002] With the rapid development of organosilicon monomers, the output of high-boiling-point substances produced as a byproduct in the monomer production process has increased sharply, leading to large-scale stockpiling and storage blockages. This causes not only environmental and safety issues but also a serious waste of resources. There is an urgent need to develop efficient and green catalysts for the cracking of high-boiling-point substances in organosilicon to support the green development of the industry.

[0003] Currently, tri-n-butylamine is commonly used as a catalyst to crack high-boiling-point substances to prepare chlorosilane monomers. Although the operating temperature and pressure are low, there are still fundamental problems that are difficult to overcome, as analyzed below:

[0004] (1) The catalyst tri-n-butylamine is a highly toxic chemical and must be strictly controlled during its use period. It is used as a consumable.

[0005] (2) The target product M2 has low selectivity, and the main products are low-value monomethyltrichlorosilane and monomethyldichlorosilane;

[0006] (3) The cracking rate is low, and only chlorine-rich Si-Si cracking can be achieved; the uncracked high-boiling substances mix with it to form hazardous waste, which further causes secondary pollution to human health and the ecological environment, and wastes resources; subsequent treatment is more complicated and difficult, and the environmental protection cost is huge.

[0007] (4) In a homogeneous batch reaction system, it is difficult to separate the product from the catalyst and unreacted raw materials, resulting in poor product purity;

[0008] (5) Stir-fry reaction system: Due to the limited processing scale, and given the current rapid expansion of monomer production capacity, there is an urgent need to develop a continuous and stable catalytic reaction system.

[0009] The disclosed patent documents concerning the preparation of dimethyldichlorosilane by pyrolysis of high-boiling organosilicon compounds mainly fall into the following categories:

[0010] (1) Noble metal catalysts: CN1071927A, JP54-9228, and JP54-119417 reported the cracking of high-boiling substances using noble metals Pd and Pt as catalysts, with HCl as the cracking gas source, and requiring toluene or xylene as a solvent in the reactor. However, noble metal catalysts are expensive, difficult to recycle, and difficult to purify, making large-scale industrial application difficult.

[0011] (2) Aluminum-based catalysts: US5430168, US5321147, CN1169996A, CN1634937A, CN1634936A, CN1915999A, etc., disclose a catalyst using aluminum trichloride (AlCl3) as a catalyst and HCl as the cracking gas, in a slurry bed or fixed bed reaction. Typical process conditions: reaction temperature is 300-500℃, reaction pressure is 4-7MPa, but the M2 yield is low. During the reaction, the active component AlCl3 is easily sublimated and lost, making it difficult to regenerate and recycle the catalyst. High-pressure operation places stringent requirements on the equipment.

[0012] (3) Molecular sieve and activated carbon catalyst: Dow Corning uses LZ-Y-74 molecular sieve as catalyst to crack methylchlorosilane (Si-Si) and HCl as cracking gas. To reduce costs, the company chooses activated carbon to replace molecular sieve, but the reaction temperature is 500℃ higher and the energy consumption is higher (see "Resource Utilization of By-products in the Production of Methylchlorosilane Monomer", Li Bin, Master's Thesis of Beijing University of Chemical Technology).

[0013] CN115677750A discloses a method for hydrocracking and disproportionation of high-boiling organosilicon compounds in a batch reactor on a Ni@ZSM-5 encapsulated catalyst, with an M2 selectivity >70%. On the one hand, the batch reactor has limited processing scale; on the other hand, the reaction requires a pressure of 2-5 MPa, making it difficult to determine the reaction endpoint.

[0014] CN115746042A discloses a method for catalytic cracking of high-boiling organosilicon compounds, wherein the catalyst is one or more of Fe, Zn, Ni, Ti, and Mo supported on a molecular sieve, but the cracking temperature is high, exceeding 550℃.

[0015] Given the problems of low catalyst cracking rate, low target product selectivity, difficulty in recycling, and limited processing scale in the reaction of organosilicon high-boiling point cracking to prepare dimethyldichlorosilane, there is an urgent need to develop a new type of highly efficient and green catalyst and process for organosilicon high-boiling point cracking to prepare chlorosilane monomers to support the green development of the industry. Summary of the Invention

[0016] To address the shortcomings of existing technologies, the present invention aims to provide a Co@HZ / B catalyst, its preparation method, and its applications. By mixing a Co@HZ precursor with inorganic oxides, this catalyst exhibits advantages such as high pyrolysis rate and high selectivity for target products in the cracking and disproportionation of high-boiling-point organosilicon compounds.

[0017] To achieve this objective, the present invention adopts the following technical solution:

[0018] In a first aspect, the present invention provides a method for preparing a Co@HZ / B catalyst, the method comprising the following steps: mixing a Co@HZ precursor and a B support source, and sequentially subjecting them to molding, drying, calcination and reduction to obtain a Co@HZ / B catalyst; wherein, in the Co@HZ precursor, HZ is a low-silicon-aluminum-ratio hydrogen-type molecular sieve, and the silicon-aluminum molar ratio SiO2 / Al2O3 of the low-silicon-aluminum-ratio hydrogen-type molecular sieve is 5 to 50:1; and B is an inorganic oxide support.

[0019] Compared to industrially commonly used catalysts such as triethylamine, tri-n-butylamine, and aluminum powder, the catalyst provided by this invention achieves both Si-Si and Si-C... n (n>4) The Si-CH2-Si cleavage bond is broken, and the Si, CH3 and Cl functional groups in the chlorosilane monomers obtained by cleavage are directionally disproportionated and rearranged, resulting in higher selectivity of chlorosilane monomers, especially high selectivity of dimethyldichlorosilane (M2).

[0020] In this invention, the silicon-aluminum molar ratio (SiO2 / Al2O3) of the low-silicon-aluminum-ratio hydrogen molecular sieve is 5 to 50:1, for example, it can be 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the amount of Co encapsulated in the Co@HZ precursor is 1.0 to 5.0 wt%, for example, it can be 1.0 wt%, 1.5 wt%, 1.9 wt%, 2.4 wt%, 2.8 wt%, 3.3 wt%, 3.7 wt%, 4.2 wt%, 4.6 wt%, or 5.0 wt%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, Co in the Co@HZ precursor exists in the form of sub-nano particles.

[0023] Preferably, the particle size range of the Co subnano particles in the Co@HZ precursor is 0.1 to 1.5 nm, for example, it can be 0.1 nm, 0.3 nm, 0.5 nm, 0.6 nm, 0.8 nm, 0.9 nm, 1.1 nm, 1.2 nm, 1.4 nm or 1.5 nm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] The present invention preferably uses Co sub-nano particles in the Co@HZ precursor with a particle size within the above-mentioned range, which has a better catalytic effect.

[0025] Preferably, the HZ in the Co@HZ precursor has any one or at least two combinations of molecular sieves with FAU, BEA, MWW, MFI or TON structures, wherein typical but non-limiting combinations are combinations of FAU and BEA, combinations of MWW and BEA, combinations of FAU and MWW, combinations of MFI and BEA, and combinations of FAU and TON.

[0026] Preferably, the inorganic oxide support comprises any one or a combination of at least two of aluminum oxide, magnesium oxide, zirconium oxide, or titanium oxide, wherein typical but non-limiting combinations are combinations of aluminum oxide and magnesium oxide, combinations of zirconium oxide and magnesium oxide, combinations of aluminum oxide and zirconium oxide, combinations of titanium oxide and magnesium oxide, and combinations of aluminum oxide and titanium oxide.

[0027] Preferably, the preparation of the Co@HZ precursor includes:

[0028] The Co@HZ precursor was obtained by mixing a cobalt source and a hydrogen-type molecular sieve, followed by solid-phase grinding, heat treatment, and calcination.

[0029] Preferably, the cobalt source includes cobalt nitrate.

[0030] Preferably, the hydrogen-form molecular sieve includes any one of hydrogen-form Y molecular sieve, hydrogen-form Beta molecular sieve, hydrogen-form ZSM-5 molecular sieve, hydrogen-form MCM-49 molecular sieve, or hydrogen-form ZSM-22 molecular sieve.

[0031] Preferably, the solid-phase grinding time is 2 to 10 hours, for example, it can be 2 hours, 2.9 hours, 3.8 hours, 4.7 hours, 5.6 hours, 6.5 hours, 7.4 hours, 8.3 hours, 9.2 hours or 10 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, the heat treatment temperature is 80 to 120°C, for example, it can be 80°C, 85°C, 89°C, 94°C, 98°C, 103°C, 107°C, 112°C, 116°C or 120°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] The present invention preferably controls the heat treatment temperature within the above-mentioned range. When the heat treatment temperature is too high, there are problems such as high energy consumption and uneven cobalt dispersion. When the heat treatment temperature is too low, there are problems such as cobalt nitrate not melting and being difficult to disperse.

[0034] Preferably, the heat treatment time is 8 to 24 hours, for example, it can be 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 17 hours, 19 hours, 21 hours, 23 hours or 24 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the roasting temperature is 300-500℃, for example, 300℃, 323℃, 345℃, 367℃, 389℃, 412℃, 434℃, 456℃, 478℃ or 500℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] The present invention preferably controls the calcination temperature within the above-mentioned range. When the calcination temperature is too high, there are problems such as mutual interference between the two sites. When the calcination temperature is too low, there are problems such as incomplete decomposition of nitrates.

[0037] Preferably, the roasting time is 2 to 8 hours, for example, 2 hours, 2.7 hours, 3.4 hours, 4 hours, 4.7 hours, 5.4 hours, 6 hours, 6.7 hours, 7.4 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the roasting atmosphere is any one or a combination of at least two of air, oxygen, nitrogen or argon, wherein typical but non-limiting combinations are combinations of air and oxygen, combinations of nitrogen and oxygen, combinations of air and nitrogen, and combinations of argon and oxygen.

[0039] Preferably, the reduction temperature is 400 to 600°C, for example, 400°C, 423°C, 445°C, 467°C, 489°C, 512°C, 534°C, 556°C, 578°C or 600°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the restoration time is 4 to 12 hours, for example, it can be 4 hours, 4.9 hours, 5.8 hours, 6.7 hours, 7.6 hours, 8.5 hours, 9.4 hours, 10.3 hours, 11.2 hours or 12 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the reducing atmosphere is a hydrogen atmosphere.

[0042] Preferably, other additives are also added to the mixture, such as nitric acid and / or guar gum powder.

[0043] In a second aspect, the present invention provides a Co@HZ / B catalyst, wherein the Co@HZ / B catalyst is prepared by the preparation method of the Co@HZ / B catalyst described in the first aspect.

[0044] Preferably, the Co@HZ / B catalyst comprises a Co@HZ active component and a B support, wherein B is an inorganic oxide support.

[0045] Preferably, the content of the Co@HZ active component in the Co@HZ / B catalyst is 50-80 wt%, for example, it can be 50 wt%, 54 wt%, 57 wt%, 60 wt%, 64 wt%, 67 wt%, 70 wt%, 74 wt%, 77 wt%, or 80 wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The content of the B support is 20-50 wt%, for example, it can be 20 wt%, 24 wt%, 27 wt%, 30 wt%, 34 wt%, 37 wt%, 40 wt%, 44 wt%, 47 wt%, or 50 wt%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0046] In this invention, the content of the Co@HZ active component in the Co@HZ / B catalyst is controlled within the above-mentioned range. When the content is too high, there are problems such as poor catalyst strength. When the content is too low, there are problems such as low catalytic activity and poor selectivity of chlorosilane monomers.

[0047] Preferably, the Co content in the Co@HZ active component is 1.0 to 5.0 wt%, for example, it can be 1.0 wt%, 1.45 wt%, 1.89 wt%, 2.34 wt%, 2.78 wt%, 3.23 wt%, 3.67 wt%, 4.12 wt%, 4.56 wt%, or 5.0 wt%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] In this invention, the content of Co in the Co@HZ active component of the Co@HZ / B catalyst is controlled within the above-mentioned range. When the content is too high, there are problems such as uneven dispersion and easy agglomeration of Co nanoparticles in the prepared catalyst. When the content is too low, there are problems such as low cracking activity of the prepared catalyst.

[0049] Preferably, the B-carrier comprises any one or a combination of at least two of alumina, magnesium oxide, zirconium oxide, or titanium oxide, wherein typical but non-limiting combinations are combinations of alumina and magnesium oxide, combinations of zirconium oxide and magnesium oxide, combinations of alumina and zirconium oxide, combinations of titanium oxide and magnesium oxide, and combinations of alumina and titanium oxide.

[0050] Thirdly, the present invention provides the use of the Co@HZ / B catalyst described in the second aspect in the cracking and disproportionation of organosilicon high-boiling compounds.

[0051] The Co@HZ / B catalyst provided by this invention can be used in organosilicon disproportionation pyrolysis using a fixed-bed catalytic process. The reaction conditions are mild, with a pressure of 0.1–1.0 MPa, significantly lower than that of a batch reactor (3–7 MPa), greatly reducing equipment investment costs. The catalyst described in this invention is lossless and additive-free during use, making it environmentally friendly, highly efficient in pyrolysis, and easily scalable.

[0052] Furthermore, the method provided by this invention has high selectivity for chlorosilane monomers, with a total selectivity of >95% for monomethyldichlorosilane, dimethylmonochlorosilane, trimethylmonochlorosilane, and dimethyldichlorosilane.

[0053] Preferably, the application includes: the high-boiling-point organosilicon compound and the cracked gas undergoing a cracking disproportionation reaction in the presence of a Co@HZ / B catalyst.

[0054] Preferably, the high-boiling organosilicon compounds include Si-Si, Si-CH2-Si, or Si-C. n A mixture composed of bonds such as (n>4); wherein the proportion of silane containing Si-Si exceeds 70%, for example, it can be 71%, 72%, 75%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%, etc.

[0055] Preferably, the pyrolysis gas includes any one or a combination of at least two of hydrogen, hydrogen chloride, or chloromethane, wherein typical but non-limiting combinations are a combination of hydrogen and hydrogen chloride, a combination of chloromethane and hydrogen chloride, or a combination of hydrogen and chloromethane.

[0056] Preferably, the temperature of the pyrolysis disproportionation reaction is 300-450°C, for example, 300°C, 323°C, 345°C, 367°C, 389°C, 412°C, 434°C or 450°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] Preferably, the pressure of the pyrolysis disproportionation reaction is 0.1 to 1.5 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.2 MPa or 1.5 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0058] Preferably, the mass hourly space velocity (MSV) of the high-boiling-point organosilicon compound in the pyrolysis disproportionation reaction is 0.05–1.0 h⁻¹. -1 For example, it could be 0.05h -1 0.16h -1 0.27h -1 0.37h-1 0.48h -1 0.58h -1 0.69h -1 0.79h -1 0.9h -1 or 1.0h -1 The values ​​are not limited to those listed; other unlisted values ​​within this range also apply.

[0059] Preferably, the reactor for the pyrolysis disproportionation reaction includes any one of a fixed bed, a moving bed, a fluidized bed, or a slurry bed.

[0060] The present invention does not impose any special restrictions on the drying process described above. Any device and method known to those skilled in the art for drying can be used. Adjustments can also be made according to the actual process. For example, it can be air drying, vacuum drying, oven drying, or freeze drying, or a combination of different methods.

[0061] Compared with the prior art, the present invention has at least the following beneficial effects:

[0062] (1) The preparation method of the Co@HZ / B catalyst provided by the present invention can produce a catalyst with high catalytic activity and high selectivity for methylchlorosilane monomers with a relatively simple process, and has broad application prospects.

[0063] (2) The Co@HZ / B catalyst provided by this invention has a high cracking rate of organosilicon, with a cracking rate of over 90%, and a selectivity of over 90% for methylchlorosilane, exhibiting excellent catalytic stability and great application potential. Attached Figure Description

[0064] Figure 1 This is an HRTEM image of the catalyst prepared in Example 1 of the present invention.

[0065] Figure 2 This is an HRTEM image of the catalyst prepared in Example 3 of the present invention. Detailed Implementation

[0066] 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.

[0067] Example 1

[0068] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst, the method of which includes the following steps:

[0069] (1) Co@HBeta synthesis: The method disclosed in Example 1 of ZL201911225860.4 was followed. HBeta molecular sieves with a BEA structure and a silicon-to-aluminum ratio of 25 were mixed with cobalt nitrate and ground for 4 hours. The resulting mixture was then placed in a sealed container at 80°C and heated for 24 hours. After removal, it was calcined at 450°C for 3 hours to obtain Co@HBeta. The cobalt nanoparticles had a particle size range of 0.2–0.8 nm and a Co content of 4.2 wt%. Figure 1 As shown.

[0070] (2) Preparation of Co@HBeta / Al2O3 catalyst: Co@HBeta, Al2O3, water, guar gum powder and nitric acid were mixed evenly, extruded into strips and then dried, calcined at 450℃ for 4h and reduced at 500℃ for 6h in a hydrogen atmosphere to obtain the Co@HBeta / Al2O3 catalyst.

[0071] Example 2

[0072] This embodiment provides a method for preparing a Co@HY / ZrO2 catalyst, which includes the following steps:

[0073] (1) Co@HY synthesis: The method disclosed in Example 1 of ZL201911225860.4 was followed. HY molecular sieve with FAU structure and a silicon-to-aluminum ratio of 5 was mixed with cobalt nitrate and ground for 4 h. The resulting mixture was placed in a sealed container at 90 °C and heated for 12 h. After removal, it was calcined at 500 °C for 2 h to obtain Co@HY. The particle size range of the cobalt nanoparticles was 0.5-1.0 nm and the Co content was 4.5 wt%.

[0074] (2) Preparation of Co@HY / ZrO2 catalyst: Co@HY, ZrO2, water, guar gum powder and guar gum nitrate powder are mixed evenly, extruded into strips and then dried, calcined at 300℃ for 8h, and reduced at 600℃ for 4h in a hydrogen atmosphere to obtain the Co@HY / ZrO2 catalyst.

[0075] Example 3

[0076] This embodiment provides a method for preparing a Co@HMCM-49 / TiO2 catalyst, which includes the following steps:

[0077] (1) Synthesis of Co@HMCM-49: The method disclosed in Example 1 of ZL201911225860.4 was followed. HMCM-49 molecular sieve with a silicon-to-aluminum ratio of 50 and a MWW structure was mixed with cobalt nitrate and ground for 8 hours. The resulting mixture was then placed in a sealed container at 120°C and heated for 8 hours. After removal, it was calcined at 400°C for 5 hours to obtain Co@HMCM-49. The cobalt nanoparticles had a particle size range of 0.7–1.2 nm and a Co content of 5.0 wt%. Figure 2 As shown.

[0078] (2) Preparation of Co@HMCM-49 / TiO2 catalyst: Co@HMCM-49, TiO2, water, guar gum powder and nitric acid were mixed evenly, extruded into strips and then dried, calcined at 500℃ for 2h and reduced at 400℃ for 12h in a hydrogen atmosphere to obtain the Co@HMCM-49 / TiO2 catalyst.

[0079] Example 4

[0080] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst. The preparation method of the Co@HBeta / Al2O3 catalyst is the same as that in Example 1, except that the silicon-to-aluminum ratio of the HBeta molecular sieve is 73, and will not be repeated here.

[0081] Compared with the catalyst prepared in Example 1, the Co nanoparticles on the catalyst prepared in this example exhibit agglomeration, with a size of about 1 to 3 nm.

[0082] Example 5

[0083] This embodiment provides a method for preparing a Co@HBeta / MgO catalyst. The preparation method of the Co@HBeta / MgO catalyst is the same as that in Example 1, except that Al2O3 is replaced with MgO, and will not be repeated here.

[0084] Example 6

[0085] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst. The preparation method of the Co@HBeta / Al2O3 catalyst is the same as that in Example 1, except that the Co content in Co@HBeta is 6.0 wt%, and will not be repeated here.

[0086] Compared with the catalyst prepared in Example 1, the Co nanoparticles on the catalyst prepared in this example exhibit agglomeration, with a size of approximately 1–3.5 nm.

[0087] Example 7

[0088] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst. The preparation method of the Co@HBeta / Al2O3 catalyst is the same as that in Example 1, except that the Co content in Co@HBeta is 0.5wt%, and will not be repeated here.

[0089] Compared with the catalyst prepared in Example 1, the catalyst prepared in this example has low catalytic cracking activity in the high-boiling-point cracking disproportionation reaction.

[0090] Example 8

[0091] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst. The preparation method of the Co@HBeta / Al2O3 catalyst is the same as that in Example 1, except that the content of Al2O3 is 55wt%, and will not be repeated here.

[0092] Compared with the catalyst prepared in Example 1, the catalyst prepared in this example has low catalytic cracking activity in the high-boiling-point cracking disproportionation reaction.

[0093] Example 9

[0094] This embodiment provides a method for preparing a Co@HBeta / Al2O3 catalyst. The preparation method of the Co@HBeta / Al2O3 catalyst is the same as that in Example 1, except that the content of Al2O3 is 10wt%, and will not be repeated here.

[0095] Compared with the catalyst prepared in Example 1, the catalyst prepared in this example has poor strength and is prone to pulverization in the high-boiling-point cracking and disproportionation reaction, leading to bed blockage.

[0096] Comparative Example 1

[0097] This comparative example provides a Co@HBeta catalyst. The preparation method of the Co@HBeta catalyst is the same as that of Example 1 except that step (2) is omitted, and will not be repeated here.

[0098] Taking Examples 1 and 3 as examples, HRTEM was used for detection, and the resulting images of the catalysts are shown below. Figures 1-2 As shown, from Figures 1-2 It can be seen that, Figures 1-2 No obvious agglomerated metal nanoparticles were present.

[0099] The particle size of the catalyst was detected by HRTEM analysis, the composition of the catalyst was detected by XRF analysis, and the strength of the catalyst was tested by a strength tester.

[0100] The main components and contents of the above embodiments and comparative examples are shown in Table 1.

[0101] Table 1

[0102]

[0103] The composition of the high-boiling-point organosilicon compounds in the application examples is shown in Table 2.

[0104] Table 2

[0105] <![CDATA[CH2=CHCH2SiCl2CH3]]> 3.3 <![CDATA[(CH3)3Si-CH2-Si(CH3)3]]> 5.5 <![CDATA[(CH3)3Si-Si(CH3)2Cl]]> 10.1 <![CDATA[(CH3)2ClSi-O-Si(CH3)2Cl]]> 2.5 <![CDATA[(CH3)2ClSi-Si(CH3)2Cl]]> 15.8 <![CDATA[CH3SiCl2-CH2CH2CH3]]> 6.4 <![CDATA[(CH3)3Si-CH2-Si(CH3)2Cl]]> 5.3 <![CDATA[(CH3)2SiCl-SiCH3Cl2]]> 30.5 <![CDATA[CH3SiCl2-SiCH3Cl2]]> 15.8 <![CDATA[(CH3)2ClSi-CH2-Si(CH3)2Cl]]> 4.8

[0106] Application Example 1-1

[0107] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds, the method comprising:

[0108] A fixed-bed reactor was used to pass high-boiling-point organosilicon compounds (composition as shown in Table 2) and hydrogen-hydrogen chloride (H2 / HCl) into a catalyst packed with the catalyst prepared in Example 1. The reactor was operated at a temperature of 350°C, a pressure of 0.5 MPa, and a feed mass hourly space velocity (WHSV) of 0.15 h⁻¹ for the high-boiling-point organosilicon compounds. -1 Under certain conditions, a pyrolysis reaction is carried out to obtain reactants containing chlorosilane monomers.

[0109] Application Example 1-2

[0110] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds. The only difference between this method and Application Example 1-1 is that the pyrolysis reaction temperature is 450°C, the pressure is 1.5 MPa, and the feed mass hourly space velocity (WHSV) of the organosilicon high-boiling-point compounds is 0.3 h⁻¹. -1 .

[0111] Application Example 2-1

[0112] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds, the method comprising:

[0113] A fixed-bed reactor was used to pass high-boiling-point organosilicon compounds (composition as shown in Table 2) and hydrogen-hydrogen chloride (H2 / HCl) into a catalyst packed with the catalyst prepared in Example 2. The reactor was operated at a temperature of 380°C, a pressure of 0.5 MPa, and a feed mass hourly space velocity (WHSV) of 0.3 h⁻¹ for the high-boiling-point organosilicon compounds. -1 Under certain conditions, a pyrolysis reaction is carried out to obtain reactants containing chlorosilane monomers.

[0114] Application Example 2-2

[0115] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds. The only difference between this method and Application Example 2-1 is that the pyrolysis reaction temperature is 450°C, the pressure is 1.5 MPa, and the feed mass hourly space velocity (WHSV) of the organosilicon high-boiling-point compounds is 0.5 h⁻¹. -1 .

[0116] Application Example 3-1

[0117] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds, the method comprising:

[0118] A fixed-bed reactor was used to pass high-boiling-point organosilicon compounds (composition as shown in Table 2) and hydrogen-hydrogen chloride (H2 / HCl) into a catalyst packed with the catalyst prepared in Example 3. The reactor was operated at a temperature of 300°C, a pressure of 0.5 MPa, and a feed mass hourly space velocity (WHSV) of 0.1 h⁻¹ for the high-boiling-point organosilicon compounds. -1 Under certain conditions, a pyrolysis reaction is carried out to obtain reactants containing chlorosilane monomers.

[0119] Application Example 3-2

[0120] This application example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds. The only difference between this method and Application Example 3-1 is that the pyrolysis reaction temperature is 450°C, the pressure is 1.0 MPa, and the feed mass hourly space velocity (WHSV) of the organosilicon high-boiling-point compounds is 0.5 h⁻¹. -1 .

[0121] Application Examples 4-9 and Comparative Example 1-1

[0122] Application Examples 4-9 and Comparative Example 1-1 provide a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds. Except for the use of the catalysts in Examples 4-9 and Comparative Example 1, the method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds is the same as that in Application Example 1-1, and will not be described again here.

[0123] Application Comparative Example 1-2

[0124] This application comparative example provides a method for the pyrolysis and disproportionation reaction of organosilicon high-boiling-point compounds. The only difference between this method and application comparative example 1-1 is that the pyrolysis reaction temperature is 480℃, the pressure is 1.0 MPa, and the feed mass hourly space velocity of the organosilicon high-boiling-point compounds is 0.3 h⁻¹. -1 .

[0125] Gas chromatography analysis was performed on the reactants in the above application examples and comparative examples. The test results of the above application examples and comparative examples are shown in Table 3.

[0126] Table 3

[0127]

[0128] In Tables 1-3, " / " indicates that there is no relevant data.

[0129] The following points can be observed from Tables 1 and 3:

[0130] (1) As can be seen from the comprehensive application examples 1 to 3, the Co@HZ / B catalyst provided by the present invention uses Co as the active center, Co@HZ precursor as the active component, and is mixed with B support. At the same time, the silicon-aluminum molar ratio of the low silicon-aluminum ratio hydrogen molecular sieve is strictly controlled. The particle size of Co can be controlled within 1.0 nm, and the strength of the catalyst is above 82 N. When applied to the cracking and disproportionation process of organosilicon high boiling point substances, it can significantly improve the cracking rate of high boiling point substances, with a cracking rate of over 90%, a selectivity of chlorosilane monomers of over 95%, and a selectivity of dimethyldichlorosilane of over 50%.

[0131] (2) Combining Application Examples 1-1 and Application Example 4, it can be seen that the silicon-to-aluminum ratio of the HBeta molecular sieve in Application Example 4 is too high, and the Co nanoparticles on the catalyst are agglomerated, about 1-3 nm. Finally, the cracking rate of organosilicon high boiling point substances decreased to 85.8%. This shows that the present invention can significantly improve the catalytic activity of the catalyst by strictly controlling the silicon-to-aluminum ratio of the molecular sieve.

[0132] (3) It can be seen from the combined application examples 1-1 and 6-7 that the Co content in Co@HBeta affects the aggregation of Co nanoparticles, which is about 1-3.5 nm. Ultimately, this results in the high-boiling-point decomposition rate of only 88.7% in application example 6. In application example 7, the Co content is too low, resulting in low catalytic activity of the catalyst in the decomposition and disproportionation reaction of the high-boiling-point substance. This indicates that the present invention preferably controls the Co content in Co@HBeta within a reasonable range, which has better catalytic activity.

[0133] Similarly, comparing Application Example 1 and Application Examples 8-9, it can be seen that the content of the Co@HBeta active component also has a significant effect on catalytic activity, which will not be elaborated here.

[0134] (4) By combining the application of Example 1-1, Comparative Example 1-1 and Comparative Example 1-2, it can be seen that the addition of the support can not only improve the catalytic strength of the catalyst, in which the catalyst strength in Comparative Example 1 is very low and it is difficult to operate in the fixed bed reactor for a long time; but also improve the catalytic activity of the catalyst.

[0135] 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. The use of a Co@HZ / B catalyst in the cracking and disproportionation of high-boiling organosilicon compounds, characterized in that, The applications include: the cracking and disproportionation reaction of organosilicon high-boiling-point substances and cracked gases under the action of Co@HZ / B catalyst; the reactor for the cracking and disproportionation reaction includes any one of fixed bed, moving bed, fluidized bed or slurry bed; The pressure of the cleavage disproportionation reaction is 0.1-1.5 MPa; the mass space velocity of the organosilicon high-boiling substance in the cleavage disproportionation reaction is 0.05-1.0 h -1 ; The preparation method of the Co@HZ / B catalyst includes the following steps: The Co@HZ precursor and B support source were mixed and then subjected to molding, drying, calcination and reduction in sequence to obtain the Co@HZ / B catalyst. In the Co@HZ precursor, HZ is a low-silicon-aluminum-ratio hydrogen-type molecular sieve, and the silicon-aluminum molar ratio (SiO2 / Al2O3) of the low-silicon-aluminum-ratio hydrogen-type molecular sieve is 5~50:1; B is an inorganic oxide support. The Co@HZ / B catalyst comprises a Co@HZ active component and a B support, wherein the content of the Co@HZ active component in the Co@HZ / B catalyst is 50-80 wt%. The preparation of the Co@HZ precursor includes: The Co@HZ precursor was obtained by mixing a cobalt source and a hydrogen-type molecular sieve, followed by solid-state grinding, heat treatment, and calcination. In the Co@HZ precursor, Co exists in the form of sub-nano particles.

2. The use according to claim 1, characterized in that, The amount of Co encapsulated in the Co@HZ precursor is 1.0~5.0 wt%.

3. The use according to claim 1, characterized in that, The Co sub-nano particles in the Co@HZ precursor have a particle size range of 0.1~1.5nm.

4. The use according to claim 1, characterized in that, The Co@HZ precursor contains HZ with any one or at least two of the following molecular sieve structures: FAU, BEA, MWW, MFI, or TON.

5. The use according to claim 1, characterized in that, The inorganic oxide support includes any one or a combination of at least two of aluminum oxide, magnesium oxide, zirconium oxide, or titanium oxide.

6. The use according to claim 1, characterized in that, The cobalt source includes cobalt nitrate.

7. The use according to claim 1, characterized in that, The hydrogen-type molecular sieve includes any one or a combination of at least two of the following: hydrogen-type Y molecular sieve, hydrogen-type Beta molecular sieve, hydrogen-type ZSM-5 molecular sieve, hydrogen-type MCM-49 molecular sieve, or hydrogen-type ZSM-22 molecular sieve.

8. The use according to claim 1, characterized in that, The solid-phase grinding time is 2~10 hours.

9. The use according to claim 1, characterized in that, The heat treatment temperature is 80~120℃.

10. The use according to claim 1, characterized in that, The heat treatment time is 8~24 hours.

11. The use according to claim 1, characterized in that, The calcination temperature is 400~500℃.

12. The use according to claim 1, characterized in that, The calcination time is 2-5 hours.

13. The use according to any one of claims 1 to 12, characterized in that, The roasting temperature is 300~500℃.

14. The use according to any one of claims 1 to 12, characterized in that, The roasting time is 2 to 8 hours.

15. The use according to any one of claims 1 to 12, characterized in that, The roasting atmosphere is any one or a combination of at least two of the following: air, oxygen, nitrogen, or argon.

16. The use according to any one of claims 1 to 12, characterized in that, The reduction temperature is 400~600°C.

17. The use according to any one of claims 1 to 12, characterized in that, The restoration time is 4~12 hours.

18. The use according to any one of claims 1 to 12, characterized in that, The reducing atmosphere is a hydrogen atmosphere.

19. The use according to any one of claims 1 to 12, characterized in that, The content of B support in the Co@HZ / B catalyst is 20~50wt%.

20. The use according to any one of claims 1 to 12, characterized in that, The cracked gas includes any one or a combination of at least two of hydrogen, hydrogen chloride, or chloromethane.

21. The use according to any one of claims 1 to 12, characterized in that, The temperature of the pyrolysis disproportionation reaction is 300~450℃.

Images