A method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue

Abstract

The application provides a method for preparing methyl chlorosilane monomers from organic silicon slurry residue recovery heavy high-boiling substances, wherein the organic silicon slurry residue recovery heavy high-boiling substances are subjected to a cracking reaction with hydrogen under the action of a non-noble metal-silicon aluminum colloid bifunctional catalyst to prepare methyl chlorosilane monomers; the method effectively solves the bottleneck problem of difficult treatment of the organic silicon slurry residue, and realizes resource utilization and high-value utilization of the organic silicon slurry residue; the operation process is simple, easy to operate, and mild in reaction conditions, and the single-pass conversion rate of the heavy high-boiling substances and the yield of the methyl chlorosilane monomers are both high, and the industrial application value is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organosilicon monomer production, and particularly relates to a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organosilicon slurry residue. BACKGROUND

[0002] At present, methyl chlorosilane is a very important platform raw material for synthesizing organosilicon materials. In the process of producing methyl chlorosilane by a direct method, there are decomposition, disproportionation, hydrolysis and other side reactions, and the reaction mechanism is complex. After the target product is separated, organosilicon slurry residue and high-boiling substances are produced. With the rapid expansion of the production of organosilicon monomers, a large amount of organosilicon slurry residue is also produced, which gradually becomes an obstacle to the sustainable development of the industry.

[0003] The organosilicon slurry residue accounts for about 3% of the amount of chlorosilane monomers, mainly composed of heavy high-boiling substances containing Si-Si, Si-Si-Si, Si-O-Si, Si-C-Si and a small amount of silicon powder, copper powder and trace amounts of metal elements Fe, Zn, Al, Sn, etc. The solid residue content is about 20-75%. Moreover, organosilicon production enterprises usually hydrolyze the slurry residue, which seriously pollutes the discharged hydrogen chloride, and a large amount of waste is produced after hydrolysis, which requires a large amount of treatment work. Most importantly, a large amount of heavy high-boiling substances cannot be recycled, resulting in resource waste.

[0004] At present, there are related research reports on the method for preparing methyl chlorosilane monomers by cracking high-boiling substances, such as CN1071927A, CN1169996A and CN101824047A. In 2011, Li Bin also reported a method for preparing methyl chlorosilane monomers by cracking high-boiling substances (see “Resource utilization of by-products in the production of methyl chlorosilane monomers”, Li Bin, Master's Degree Thesis of Beijing University of Chemical Technology). However, in the above-mentioned reports, the high-temperature cracking requires harsh conditions for the reactor, and the carbon deposition and coking are serious and irreversible.

[0005] Although catalytic cracking is considered an effective method, the development of catalysts is the core. Moreover, at present, the industrial catalysts mainly crack disilane, and there is no significant catalytic cracking effect reported for heavy high-boiling substances with structures such as Si-(CH2) n -Si (n≥1), Si-O-Si.

[0006] Therefore, it is urgent to develop a resource utilization method for effectively catalytic cracking of heavy high-boiling substances to solve the environmental protection and economic benefit problems in the prior art. SUMMARY

[0007] In view of the problems in the prior art, the present application provides a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue, which uses heavy high-boiling substances recovered from organic silicon slurry residue as raw material and a non-noble metal-silica-alumina bifunctional catalyst prepared by a coprecipitation method as a cracking catalyst to catalytically crack the heavy high-boiling substances with structures such as Si-(CH2) n -Si(n≥1), Si-O-Si, etc., to obtain methyl chlorosilane monomer, thereby realizing the value recovery of heavy high-boiling substances and relieving environmental pressure.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] The present application provides a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue, which uses heavy high-boiling substances recovered from organic silicon slurry residue as raw material and a non-noble metal-silica-alumina bifunctional catalyst prepared by a coprecipitation method as a cracking catalyst to catalytically crack the heavy high-boiling substances with structures such as Si-(CH2)

[0010] The difficulty of the present application lies in how to improve the conversion rate of heavy high-boiling substances, wherein the catalytic cracking of heavy high-boiling substances with structures such as Si-(CH2) n -Si(n≥1), Si-O-Si, etc., is relatively difficult, the non-noble metal in the non-noble metal-silica-alumina bifunctional catalyst of the present application is uniformly loaded in the silica-alumina carrier and embedded in the interior of the silica-alumina carrier, which avoids the aggregation of the active components of the catalyst during the reaction and enables the cracking of Si-Si bonds or Si-C bonds in the heavy high-boiling substances, thereby significantly improving the conversion rate of the heavy high-boiling substances and enhancing the utilization value of the heavy high-boiling substances. In addition, the non-noble metal-silica-alumina catalyst is prepared by coprecipitation, which is low in cost and more conducive to engineering promotion.

[0011] Preferably, the temperature of the cracking reaction is 250-400℃, for example, it can be 250℃, 260℃, 280℃, 300℃, 310℃, 330℃, 350℃, 360℃, 380℃ or 400℃, etc., but is not limited to the listed values, and other unlisted values within this range are also applicable.

[0012] Preferably, the hydrogen pressure of the cracking reaction is 3.0-8.0 MPa, for example, it can be 3.0 MPa, 3.3 MPa, 3.7 MPa, 4.2 MPa, 4.6 MPa, 5.0 MPa, 6.0 MPa, 7.0 MPa or 8.0 MPa, etc., but is not limited to the listed values, and other unlisted values within this range are also applicable.

[0013] Preferably, the cleavage reaction time is 2 to 8 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 6 hours, 7 hours or 8 hours, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0014] Preferably, the cleavage reaction is carried out under stirring conditions.

[0015] The cracking and disproportionation reaction of the present invention does not impose any particular limitation on the stirring speed. The speed varies according to the production output. Any stirring speed known to those skilled in the art that can be used to uniformly mix the reaction materials can be used. For example, in the pilot stage, it can be 300 to 600 r / min.

[0016] Preferably, the non-precious metal-silica-alumina gel bifunctional catalyst is prepared by a coprecipitation method. The preferred coprecipitation method can effectively inhibit the migration, agglomeration and loss of non-precious metal nanoparticles, thereby providing good catalytic stability and good application prospects. The present invention does not impose any particular restrictions on the specific process of the coprecipitation method, and any coprecipitation method that can be used to prepare non-precious metal-silica-alumina gel bifunctional catalysts well known to those skilled in the art can be used.

[0017] Preferably, the non-precious metal-silica alumina gel bifunctional catalyst accounts for 5 to 15 wt% of the heavy high boiling materials, for example, it can be 5 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt% or 15 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0018] Preferably, the silicon-aluminum ratio SiO2 / Al2O3 in the non-precious metal-silica-alumina gel bifunctional catalyst is 50:1 to 200:1, for example, it can be 50:1, 60:1, 80:1, 100:1, 110:1, 130:1, 150:1, 160:1, 180:1 or 200:1, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0019] Preferably, the non-precious metal comprises any one or a combination of at least two of Ni, Mo, Fe, Co, Zn or Cu, wherein typical but non-limiting combinations are a combination of Ni and Mo, a combination of Ni and Fe, a combination of Fe and Mo, a combination of Zn and Mo, a combination of Co and Mo, a combination of Cu and Mo, and a combination of Co and Cu.

[0020] Preferably, the content of non-noble metal in the non-noble metal-silica-alumina bifunctional catalyst is 2.0-10wt%, for example, it can be 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or 10wt%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0021] Preferably, the non-noble metal in the non-noble metal-silica-alumina bifunctional catalyst exists in the form of nanoparticles.

[0022] Preferably, the nanoparticles are uniformly embedded in the silica-alumina support.

[0023] Preferably, the non-noble metal-silica-alumina bifunctional catalyst has both acidic catalytic cracking function and hydrogenation function.

[0024] Preferably, the particle size of the non-noble metal nanoparticles is 3-10nm, for example, it can be 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0025] Preferably, the silica-alumina support in the non-noble metal-silica-alumina bifunctional catalyst has acidity.

[0026] Preferably, the components of the heavy high-boiling substance include a combination of at least two of a Si-Si-containing compound, a Si-Si-Si-containing compound, a Si-(CH2) n -Si-containing compound or a Si-O-Si-containing compound, wherein n is a natural number ≥1, and typical but non-limiting combinations are a combination of a Si-Si-containing compound and a Si-Si-Si-containing compound, a combination of a Si-Si-containing compound and a Si-O-Si-containing compound, a combination of a Si-Si-Si-containing compound and a Si-O-Si-containing compound, and a combination of a Si-CH2-Si-containing compound and a Si-O-Si-containing compound.

[0027] wherein n is a natural number ≥1, preferably n=1-7, for example, it can be 1, 2, 3, 4, 5, 6 or 7, etc.

[0028] The Si-Si in the present application refers to a compound containing Si-Si bond in the compound, and there is no special limitation on the groups connected to the other bonds on the two silicon atoms, for example, it can be any one or a combination of at least two of alkyl, hydrogen atom, chlorine atom or alkenyl. The Si-Si-Si refers to a compound containing three connected silicon atoms, and there is no special limitation on the groups connected to the other bonds on the three silicon atoms, for example, it can be any one or a combination of at least two of alkyl, hydrogen atom, chlorine atom or alkenyl. The Si-(CH2)n -Si refers to the compound containing two silicon atoms separated by at least one carbon atom, and there is no special restriction on other groups connected to silicon and carbon, for example, it can be any one or a combination of at least two of alkyl, hydrogen atom, chlorine atom or alkenyl. The Si-O-Si refers to the compound containing two silicon atoms separated by one oxygen atom, and there is no special restriction on other groups connected to silicon, for example, it can be any one or a combination of at least two of alkyl, hydrogen atom, chlorine atom or alkenyl. Typical but non-limiting combinations in the above include combinations of alkyl and hydrogen atom, combinations of hydrogen atom and chlorine atom, combinations of chlorine atom and alkenyl, etc.

[0029] Preferably, the alkyl group includes methyl and / or ethyl, etc. The alkenyl group includes vinyl and / or propenyl, etc.

[0030] The compounds in the heavy high-boiling residue in the present application have the above chemical bonds, and in the catalytic cracking disproportionation reaction, the breaking of Si-Si bond, the breaking of Si-Si bond in Si-Si-Si, and the breaking of C-Si bond in Si-(CH2) n -Si, and rearranging chlorine atom and methyl on the silicon atom again to produce dimethyldichlorosilane and other methyl chlorosilane monomers. The present application can improve the conversion rate of heavy high-boiling residue by selecting non-noble metal-silica-alumina bifunctional catalyst, while reducing the cost of catalyst.

[0031] Preferably, the content of the Si-Si-containing compound in the heavy high-boiling residue is 15-35wt%, for example, it can be 15wt%, 18wt%, 20wt%, 22wt%, 24wt%, 27wt%, 29wt%, 31wt%, 33wt% or 35wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0032] Preferably, the content of the Si-Si-Si-containing compound in the heavy high-boiling residue is 1-15wt%, for example, it can be 1wt%, 3wt%, 5wt%, 6wt%, 8wt%, 9wt%, 11wt%, 12wt%, 14wt% or 15wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0033] Preferably, the content of the Si-O-Si-containing compound in the heavy high-boiling residue is 1-15wt%, for example, it can be 1wt%, 3wt%, 5wt%, 6wt%, 8wt%, 9wt%, 11wt%, 12wt%, 14wt% or 15wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0034] Preferably, the content of the Si-(CH2)n The content of the compound of -Si is 10-35 wt%, for example, it can be 10 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%, 27 wt%, 29 wt%, 31 wt%, 33 wt%, or 35 wt%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0035] Preferably, the heavy high boiler comprises any one or a combination of at least two of disilane, vinylsilane, trisilane, or oxysilane, wherein typical but non-limiting combinations are a combination of disilane and trisilane, a combination of oxysilane and trisilane, a combination of disilane and oxysilane, a combination of vinylsilane and oxysilane.

[0036] Preferably, the heavy high-boiling residue includes any one of (CH3)3-Si-SiCl-(CH3)2, (CH3)2-SiCl-SiCl-(CH3)2, CH2=CH-CH2-SiCl-(CH3)2, CH3-SiCl2-SiCl2-CH3, (CH3)2-SiCl-CH2-SiCl-(CH3)2, Cl-CH2-SiClCH3-CH2-Cl, (CH3)2-SiCl-O-SiCl-(CH3)2, (CH3)3-Si-Si(CH3)2-SiH-(CH3)2, (CH3)3-Si-CH-Cl2, CH3-SiCl2-CH2-CH2-SiCl2-CH3, Cl-Si(CH3)2-Si(CH3)2-Si(CH3)2-Cl, CH3-(CH2)7-SiCl-(CH3)2, CH3-SiCl2-CH2-CH=CH2, or (CH3)3-Si-CH2-SiCl-(CH3)2, or a combination of at least two thereof, wherein a typical but non-limiting combination is a combination of (CH3)3-Si-SiCl-(CH3)2 and (CH3)2-SiCl-SiCl-(CH3)2, a combination of CH3-SiCl2-CH2-CH2-SiCl2-CH3 and (CH3)3-Si-CH2-SiCl-(CH3)2, a combination of CH3-SiCl2-CH2-CH=CH2 and (CH3)2-SiCl-SiCl-(CH3)2, a combination of (CH3)3-Si-CH2-SiCl-(CH3)2 and Cl-Si(CH3)2-Si(CH3)2-Si(CH3)2-Cl, a combination of (CH3)3-Si-SiCl-(CH3)2 and (CH3)2-SiCl-SiCl-(CH3)2, a combination of CH3-SiCl2-SiCl2-CH3 and (CH3)2-SiCl-SiCl-(CH3)2, a combination of (CH3)3-Si-SiCl-(CH3)2 and Cl-CH2-SiClCH3-CH2-Cl.

[0037] As a preferred technical solution of the present application, the method comprises: mixing the organosilicon slurry residue recovery heavy high-boiling residue and the non-noble metal-silica alumina gel bifunctional catalyst, the non-noble metal-silica alumina gel bifunctional catalyst accounts for 5-15wt% of the heavy high-boiling residue, the hydrogen pressure is 3.0-8.0MPa, the cracking reaction is carried out at 250-400℃ and under stirring conditions for 2-8h, and methyl chlorosilane monomer is prepared.

[0038] The non-noble metal-silica alumina double functional catalyst has a silica alumina ratio SiO2 / Al2O3=50:1-200:1, the content of non-noble metal in the non-noble metal-silica alumina double functional catalyst is 2.0-10wt%, and the nanoparticle size of the non-noble metal is 3-10nm.

[0039] Compared with the prior art, the present application has at least the following beneficial effects:

[0040] (1) The method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue provided by the present application selects a non-noble metal-silica alumina double functional catalyst as a cracking catalyst, has the advantages of high conversion rate and selectivity, wherein the heavy high-boiling substance conversion rate is more than 50% under the preferred conditions, the heavy high-boiling substance conversion rate is more than 70% under the more preferred conditions, and even more than 90%, and the methyl chlorosilane monomer yield is more than 40% under the preferred conditions, more than 50% under the more preferred conditions, wherein the dimethyldichlorosilane yield is more than 30% under the preferred conditions, and even more than 55%, which greatly improves the value of the heavy high-boiling substances.

[0041] (2) The catalyst provided by the present application is simple to make and has low cost, which greatly facilitates engineering promotion. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The XRD spectra of the Ni-SiO2-Al2O3 double functional catalyst in Example 1 and the Co-SiO2-Al2O3 double functional catalyst in Example 2.

[0043] Figure 2 The TEM image of the Ni-SiO2-Al2O3 double functional catalyst in Example 1. DETAILED DESCRIPTION

[0044] The technical solutions of the present application are further illustrated below by specific embodiments and through specific embodiments.

[0045] The present application is further described below. However, the following examples are only simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0046] The following specific examples and comparative examples are tested by taking the full components of the heavy high-boiling substances recovered from the organic silicon slurry residue of a certain factory as an example. GC-MS is used to analyze the composition content of the high-boiling substances, and the results are shown in Table 1.

[0047] Table 1

[0048]

[0049] Example 1

[0050] The embodiment provides a method for preparing methyl chlorosilane monomer from organic silicon slurry residue recovery heavy high-boiling substances, and the method comprises the following steps: mixing 50.3g of organic silicon slurry residue recovery heavy high-boiling substances and 5.0g of non-noble metal-silica alumina double functional catalyst (Ni-SiO2-Al2O3, 5.6wt% Ni, the particle size of Ni nanoparticles is 5-8nm, Si2O3 / Al2O3=100:1), placing in an autoclave, replacing air with nitrogen for three times, then replacing with hydrogen to 6.0MPa of hydrogen pressure, heating to 320 DEG C, and performing cracking reaction at 400r / min for 6h to prepare methyl chlorosilane monomer, and obtaining reaction materials;

[0051] The reaction materials are cooled to room temperature, discharged after pressure relief, and then a product containing methyl chlorosilane monomer is obtained; and specific result analysis is shown in A1 in Table 2.

[0052] The preparation method of the Ni-SiO2-Al2O3 catalyst adopts a co-precipitation method, i.e., silicon sol, aluminum sol, metal Ni precursor (Ni-ethylenediamine complex) and appropriate amount of water are hydrolyzed and co-precipitated under hydrothermal conditions at 80 DEG C for 6h, and then the Ni-SiO2-Al2O3 catalyst can be obtained by placing in a 105 DEG C oven for drying, calcination and reduction.

[0053] The XRD and TEM analysis of the Ni-SiO2-Al2O3 catalyst is shown in Figure 1 and Figure 2 As can be seen from the figures, the catalyst has no obvious characteristic diffraction peak of Ni species, and the silica alumina gel is in an amorphous state; the Ni nanoparticles are about 5-8nm, are uniformly distributed, have uniform particle size, and are embedded in the silica alumina gel carrier.

[0054] Embodiment 2

[0055] The embodiment provides a method for preparing methyl chlorosilane monomer from organic silicon slurry residue recovery heavy high-boiling substances, and the method comprises the following steps: mixing 50.2g of organic silicon slurry residue recovery heavy high-boiling substances and 6.0g of non-noble metal-silica alumina double functional catalyst (Co-SiO2-Al2O3, 5.1wt% Co, the particle size of Co nanoparticles is 1.1-1.3nm, Si2O3 / Al2O3=50:1), placing in an autoclave, replacing air with nitrogen for four times, then replacing with hydrogen to 4.0MPa of hydrogen pressure, heating to 260 DEG C, and performing cracking reaction at 600r / min for 8h to prepare methyl chlorosilane monomer, and obtaining reaction materials;

[0056] The reaction materials are cooled to room temperature, discharged after pressure relief, and then a product containing methyl chlorosilane monomer is obtained; and specific result analysis is shown in A2 in Table 2.

[0057] The Co-SiO2-Al2O3 catalyst is prepared by a co-precipitation method. The metal Ni precursor is replaced by the metal Co precursor, and the other conditions are the same as in Example 1. Figure 1 It can be seen that there is no obvious diffraction peak of Co in the catalyst, indicating that Co is embedded in the inside of the silica-alumina gel.

[0058] Example 3

[0059] The present example provides a method for preparing methyl chlorosilane monomer from organic silicon slurry residue recovery heavy high-boiling, which comprises: mixing 50.2 g of organic silicon slurry residue recovery heavy high-boiling and 7.5 g of non-noble metal-silica-alumina gel bifunctional catalyst (Mo-SiO2-Al2O3, 9.8 wt% Mo, the particle size of Mo nanoparticles is 5-7 nm, Si2O3 / Al2O3=150:1), placing in an autoclave, replacing air with nitrogen for 4 times, then replacing with hydrogen to a hydrogen pressure of 5.0 MPa, heating to 380℃, and cracking at 600 r / min for 6 h to prepare methyl chlorosilane monomer, and obtaining the reacted material;

[0060] After the reacted material is cooled to room temperature and discharged after pressure relief, a product containing methyl chlorosilane monomer is obtained; the specific result analysis is shown in A3 in Table 2.

[0061] The Mo-SiO2-Al2O3 catalyst is prepared by the method of Example 1, and the metal Ni precursor is replaced by the metal Mo precursor.

[0062] Example 4

[0063] The present example provides a method for preparing methyl chlorosilane monomer from organic silicon slurry residue recovery heavy high-boiling, which comprises: mixing 50.3 g of organic silicon slurry residue recovery heavy high-boiling and 3.0 g of non-noble metal-silica-alumina gel bifunctional catalyst (Ni-SiO2-Al2O3, 5.6 wt% Ni, the particle size of Ni nanoparticles is 3-7 nm, Si2O3 / Al2O3=200:1), placing in an autoclave, replacing air with nitrogen for 5 times, then replacing with hydrogen to a hydrogen pressure of 2.5 MPa, heating to 250℃, and cracking at 400 r / min for 6 h to prepare methyl chlorosilane monomer, and obtaining the reacted material;

[0064] After the reacted material is cooled to room temperature and discharged after pressure relief, a product containing methyl chlorosilane monomer is obtained; the specific result analysis is shown in A4 in Table 2.

[0065] The Ni-SiO2-Al2O3 catalyst is prepared by the same method as in Example 1

[0066] Example 5

[0067] This example provides a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue, which is the same as example 1 except that "5.0 g Ni-SiO2-Al2O3 catalyst" in example 1 is replaced by "2.0 g Ni-SiO2-Al2O3 catalyst".

[0068] Example 6

[0069] This example provides a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue, which is the same as example 1 except that the reaction temperature is 200°C.

[0070] Comparative Example 1

[0071] This comparative example provides a method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue, which is the same as example 1 except that "Ni-SiO2-Al2O3 catalyst" in example 1 is replaced by "Ni / SiO2-Al2O3 catalyst prepared by impregnation method, 5.6 wt% Ni, Si2O3 / Al2O3 = 100:1".

[0072] Test method: GC-MS was used to analyze the composition of the product after reaction in the above examples and comparative examples, and the conversion rate of heavy high-boiling substances and the yield of methyl chlorosilane were calculated, and the results are shown in Table 2. Wherein A1-A6 represent examples 1-6 respectively, and D1 represents comparative example 1.

[0073] Table 2

[0074] Liquid product yield (%) A1 A2 A3 A4 A5 A6 D1 (CH3)2-SiH-Cl 8.2 6.5 4.1 4.8 2.1 1.1 2.8 CH3-SiH-Cl2 9.7 3.8 5.1 7.8 3.1 1.8 4.7 (CH3)3-Si-Cl 4.6 3.3 3.9 5.1 2.2 0.5 2.4 (CH3)2-Si-Cl2 55.8 31.8 35.1 43.4 28.9 14.9 15.3 Other chlorosilane monomers 13.2 6.1 14.7 11.2 7.8 3.5 4.9 Methyl chlorosilane monomer yield (%) 78.3 45.4 48.2 62.3 36.3 18.3 25.2 Single pass conversion of heavy high boiler (%) 91.5 51.5 62.9 73.5 44.1 21.8 30.1

[0075] As can be seen from Table 2, the method for preparing methyl chlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue provided in examples 1-4 significantly improves the single-pass conversion rate of heavy high-boiling substances, wherein the conversion rate is more than 50%, under preferred conditions, the conversion rate is more than 70%, and even more than 90%, and under preferred conditions, the yield of methyl chlorosilane monomer is more than 40%, and under more preferred conditions, it is more than 60%, and the selectivity of dimethyldichlorosilane is more than 30% under preferred conditions, greatly improving the value of heavy high-boiling substances.

[0076] As can be seen from example 1 and example 6, the reaction temperature has a great influence on the cracking reaction, although the temperature of the cracking reaction has been reduced to 250-400°C by using the selected catalyst of the present application, but the cracking reaction is difficult to proceed below 250°C, the present application matches the preferred temperature range on the basis of the selected non-noble metal-silica-alumina gel bifunctional catalyst, reduces the preparation cost of the catalyst, and at the same time guarantees the conversion rate and selectivity of the cracking reaction.

[0077] From the combination of Example 1 and Example 5, it can be seen that the amount of catalyst has certain influence on the reaction, and the present application can further improve the conversion rate and selectivity of the cracking reaction by preferably selecting a specific range of catalyst amount.

[0078] From the combination of Example 1 and Comparative Example 1, it can be seen that the catalyst prepared by the coprecipitation method in Example 1 has a single-pass conversion rate of heavy high-boiling substances as high as 91.5% and a yield of dimethyldichlorosilane as high as 55.8%, while the catalyst prepared by the impregnation method in Comparative Example 1 has a single-pass conversion rate of heavy high-boiling substances of only 30.1% and a yield of dimethyldichlorosilane of only 15.3%, which shows that the non-noble metal-silica-alumina double functional catalyst with non-noble metal embedded in the silica-alumina carrier prepared by the coprecipitation method of the present application significantly improves the conversion rate, the yield of methylchlorosilane monomer and the yield of dimethyldichlorosilane.

[0079] In summary, the method for preparing methylchlorosilane monomer from heavy high-boiling substances recovered from organic silicon slurry residue provided by the present application solves the environmental and economic problems in the prior art, realizes the value recovery of heavy high-boiling substances, relieves the environmental pressure and has high industrial application value.

[0080] The applicant declares that the above examples are used to illustrate the detailed structural features of the present application, but the present application is not limited to the above detailed structural features, i.e. it does not mean that the present application must rely on the above detailed structural features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the components selected by the present application, addition of auxiliary components, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing methylchlorosilane monomer by recovering heavy high boiling products from organosilicon slurry, characterized in that: The heavy high-boiling products recovered from the organosilicon slurry are subjected to a cracking reaction with hydrogen under the action of a non-precious metal-silica-alumina gel dual-function catalyst to prepare methylchlorosilane monomer; the non-precious metal in the non-precious metal-silica-alumina gel dual-function catalyst is embedded in the silica-alumina gel carrier; The temperature of the cracking reaction is 250-400°C; The non-noble metal-silica-alumina gel bifunctional catalyst is prepared by a co-precipitation method; The non-noble metal includes any one of Ni, Mo, Fe, Co, Zn or Cu, or a combination of at least two of them.

2. The method according to claim 1, characterized in that The hydrogen pressure of the cracking reaction is 3.0-8.0 MPa.

3. The method according to claim 1, characterized in that The cleavage reaction time is 2 to 8 hours.

4. The method according to claim 1 or 2, characterized in that The cleavage reaction is carried out under stirring conditions.

5. The method according to claim 1, wherein The non-noble metal-silica alumina gel dual-function catalyst accounts for 5 to 15 wt% of the heavy high boiling materials.

6. The method according to claim 1, characterized in that The silicon-aluminum ratio SiO2 / Al2O3 in the non-precious metal-silica-aluminum gel bifunctional catalyst is 50:1 to 200:

1.

7. The method according to claim 1, characterized in that The content of the non-noble metal in the non-noble metal-silica alumina gel dual-function catalyst is 2.0-10 wt %.

8. The method according to claim 1, characterized in that The non-noble metal in the non-noble metal-silica alumina gel bifunctional catalyst exists in the form of nanoparticles.

9. The method according to claim 1, characterized in that The particle size of the non-noble metal nanoparticles is 3 to 10 nm.

10. The method according to claim 1, characterized in that The silica-alumina gel carrier in the non-noble metal-silica-alumina gel bifunctional catalyst is acidic.

11. The method according to claim 1, characterized in that The heavy high boiling substances include disilane, trisilane and silane oxide.

12. The method according to claim 1, characterized in that The components of the heavy high boiling products include compounds containing Si-Si, compounds containing Si-Si-Si, compounds containing Si-(CH2) n -Si compounds or Si-O-Si containing compounds, wherein n is a natural number ≥1.

13. The method according to claim 1, wherein The method comprises: mixing organosilicon slurry residue to recover heavy high boiling products and a non-precious metal-silica-alumina gel dual-function catalyst, wherein the non-precious metal-silica-alumina gel dual-function catalyst accounts for 5-15 wt% of the heavy high boiling products, performing a cracking reaction at 250-400° C. and stirring for 2-8 hours at a hydrogen pressure of 3.0-8.0 MPa to prepare a methylchlorosilane monomer; The silicon-aluminum ratio SiO2 / Al2O3 in the non-precious metal-silica-alumina bifunctional catalyst is 50:1-200:1, the content of non-precious metal in the non-precious metal-silica-alumina bifunctional catalyst is 2.0-10wt%, and the particle size of the non-precious metal nanoparticles is 3-10nm.

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