Hydroxyl-containing organic amine grafted organic silicon high-boiling residue catalyst and cracking process

Abstract

The invention belongs to the technical field of organic silicon, and discloses a hydroxyl-containing organic amine grafted organic silicon high-boiling residue catalyst and a cracking process. The cracking catalyst is prepared by grafting the organic silicon high-boiling residue with hydroxyl-containing organic amine. And carrying out catalytic cracking on the organic silicon high-boiling residue by adopting a cracking catalyst, and converting the organic silicon high-boiling residue into a mixed product mainly comprising a dimethyldichlorosilane monomer. The method for preparing the methyl chlorosilane through catalytic cracking of the organic silicon high-boiling residues has the advantages of being high in catalytic activity, simple in process, high in safety, high in dimethyl dichlorosilane selectivity, few in generated useless monomers, high in conversion rate, few in residual waste and environmentally friendly, meanwhile, the extremely high cyclic utilization performance is achieved, and industrialization is easy to achieve.

Description

Technical Field

[0001] The present invention relates to a method for preparing a catalyst for cracking organosilicon high boilers by grafting organosilicon high boilers with hydroxy-containing organic amines. Background Art

[0002] The organosilicon industry has developed rapidly. Due to the unique chemical properties of organosilicon compounds, they have been rapidly and widely applied in various sectors of the national economy such as military, electronics, electrics, textiles, automobiles, machinery, chemical engineering, light industry, leather, paper making, paints, metals, construction, aviation, and medical treatment. The demand for them is also increasing day by day. However, the generation and treatment of high boilers have always restricted the development of the organosilicon industry.

[0003] Organosilicon high boilers are by-products of the "direct method" for producing dimethyldichlorosilane. They are a mixed liquid with a pungent odor and strong corrosiveness, containing a small amount of solids and insoluble substances, and also containing a small amount of extremely fine silicon powder. They contain a variety of compounds. With the rapid development of the organosilicon industry, the output of methylchlorosilane monomers is increasing, and the generation amount of high boilers also increases accordingly.

[0004] Using tertiary amines, N,N-dimethylformamide, N,N-diethylformamide, quaternary amine halides, quaternary phosphine halides, etc. as catalysts, the reaction is mainly an intermittent reaction. The reaction conditions are mild, the reaction temperature is low, and the yield of dimethyldichlorosilane monomers is high. But sometimes chlorides are used to introduce new organic groups, resulting in the formation of some new substances. At the same time, the catalyst price is high and it is difficult to recycle and reuse.

[0005] Rhone Plene Company in France filled a fixed-bed reactor with a combination of metal phosphate and an alkaline impregnating agent as a catalyst. Hydrogen chloride gas and organosilicon high boilers as cracking gases were introduced into the fixed-bed reactor. At 100-500°C, the organosilicon high boilers and hydrogen chloride underwent a catalytic cracking reaction under the action of the catalyst to generate silane monomers. This method has a lower reaction temperature, mild process conditions, and the catalyst is a combination of metal phosphate and an alkaline impregnating agent, which is easy to industrialize. But it has high requirements for the purity of organosilicon high boilers, poor raw material adaptability; the cracking products need to be deeply condensed and collected, otherwise the yield will decrease, the product treatment is difficult, and the subsequent product treatment system of the cracking equipment is prone to blockage, with high operation difficulty and low operation efficiency.

[0006] Transition metals such as Pd, Pt, Ru, Rh and Ni are used as catalytic components, and diatomaceous earth, alumina, charcoal, activated carbon, zeolite, silicon dioxide and the like are used as carriers to crack high-boiling substances to prepare methylchlorosilane. The active component of the catalyst used in this type of technology is a transition metal, and the carrier is a porous medium. The catalytic effect is good, the cracking is relatively thorough, and the yield of methylchlorosilane monomer is high. It can be operated both continuously and intermittently, but the reaction temperature is increased and it is operated under pressurized conditions. It is a high-temperature and high-pressure operation with harsh operating conditions. At the same time, the active component of the catalyst is a transition metal, and the carrier is an expensive porous medium, which makes the catalyst very expensive and the production cost high. In addition, catalysts with transition metals as catalytic components are generally prone to poisoning. At the same time, impurities in high-boiling organic silicon substances can easily cause the catalyst to be poisoned and fail.

[0007] The method for preparing methylchlorosilane by catalytic cracking of high-boiling organic silicon products has the advantages of high catalytic activity, simple process, high safety, high selectivity for dimethyldichlorosilane, less generation of useless monomers, high conversion rate, less residual waste, and environmental friendliness, and at the same time has extremely high recyclability and is easy to realize industrialization. Summary of the invention

[0008] The present invention mainly aims at the problems and shortcomings existing in the prior art, and discloses a method for preparing a high-boiling organosilicon cracking catalyst by grafting a hydroxyl-containing organic amine with a high-boiling organosilicon. The cracking catalyst is prepared by grafting a high-boiling organosilicon with a hydroxyl-containing organic amine. The high-boiling organosilicon is then catalytically cracked by a cracking catalyst to convert it into a mixed product mainly composed of dimethyldichlorosilane monomer. The cracking rate of the high-boiling organosilicon can reach more than 50%, in some preferred cases, the cracking rate of the high-boiling organosilicon can reach more than 60%, in some preferred cases, the cracking rate of the high-boiling organosilicon can reach more than 70%, and in some preferred cases, the cracking rate of the high-boiling organosilicon can reach more than 80%. The selectivity of dimethyldichlorosilane can reach more than 50%; in some preferred cases, the selectivity of dimethyldichlorosilane can reach more than 60%; in some preferred cases, the selectivity of dimethyldichlorosilane can reach more than 70%; in some preferred cases, the selectivity of dimethyldichlorosilane can reach more than 80%. The method for preparing methylchlorosilane by catalytic cracking of high-boiling organic silicon products has the advantages of high catalytic activity, simple process, high safety, high selectivity for dimethyldichlorosilane, less generation of useless monomers, high conversion rate, less residual waste, and environmental friendliness, and at the same time has extremely high recyclability and is easy to realize industrialization.

[0009] The present invention uses hydroxyl-containing organic amine grafted with organic silicon high boiling point to prepare an organic silicon high boiling point cracking catalyst, and its principle is as follows: The composition of high boiling point of organosilicon is as follows:

[0010] Silicone high-boiling residues contain a large number of silicon-chlorine bonds (Si-Cl) that can react with the hydroxyl groups (-OH) in organic amines containing hydroxyl groups, grafting the organic amines containing hydroxyl groups onto the silicone high-boiling residues.

[0011] The reaction equation can be expressed as: Si-Cl + R-OH → Si-O-R + HCl Among them, R-OH represents an organic amine containing a hydroxyl group.

[0012]

[0013]

[0014] In addition to the above, the silicone high-boiling residues also contain other substances containing silicon-chlorine bonds (Si-Cl) that can react with the hydroxyl groups (-OH) in the organic amines containing hydroxyl groups, grafting the organic amines containing hydroxyl groups onto the silicone high-boiling residues.

[0015] The method for catalytic cracking of silicone high-boiling residues to prepare methylchlorosilanes has the advantages of high catalytic activity, simple process, high safety, high selectivity for dimethyldichlorosilane, less formation of useless monomers, high conversion rate, less remaining waste, environmental friendliness, and extremely high recyclability, and is easy to industrialize.

[0016] The present invention has the following advantages compared with the prior art: (1) In the present invention, the small-molecule organic amine containing a hydroxyl group is grafted onto the silicone high-boiling residue in the form of a covalent bond, increasing the relative molecular mass and boiling point of the cracking catalyst. Compared with the traditional direct use of organic amine as a catalyst, the loss of the catalyst caused by entrainment is reduced.

[0017] (2) The present invention can graft two catalysts with different catalytic activities and selectivities onto the high-boiling residues. Compared with the prior art, in the present invention, by molecular compounding of organic amines with different catalytic activities, the cracking catalyst has high catalytic activity, high selectivity for dimethyldichlorosilane, less formation of useless monomers, high conversion rate, and less remaining waste.

[0018] (3) The present invention uses the by-product silicone high-boiling residue in the process of producing dimethyldichlorosilane monomer by the "direct method" as the grafting material. The resource utilization rate is effectively improved. Specific Embodiments

[0019] The following further illustrates the present invention in conjunction with specific embodiments, but these embodiments are only used to further illustrate the present invention, rather than to limit the scope of the present invention. The specific ratios, reaction parameters, and material selections involved in the specific embodiments are listed in this specific embodiment for the purpose of illustrating the present invention, and are not any limitation to the present invention.

[0020] On the one hand, the present invention provides a method for preparing a graft catalyst, comprising the following steps: Adding an organic amine containing hydroxyl groups to the high-boiling silicone compound, heating, and grafting the organic amine containing hydroxyl groups onto the high-boiling silicone compound to prepare a cracking catalyst.

[0021] Wherein, the mass ratio of the high-boiling silicone compound to the organic amine is 0.5-5:1.

[0022] Wherein, the preparation temperature of the graft cracking catalyst is 100-150 °C.

[0023] Wherein, the organic amine containing hydroxyl groups includes one or more of N,N-bis(2-hydroxyethyl)ethylenediamine, N-(2-hydroxypropyl)ethylenediamine, 2-(dimethylamino)ethanol, or 2-methylaminoethanol.

[0024] On the other hand, the present invention provides a catalytic cracking process for high-boiling silicone compounds, comprising the following steps: Adding the high-boiling silicone compound into a reactor, adding the above-mentioned cracking catalyst, then introducing or not introducing a cracking agent into the reactor, controlling the reaction temperature at 100-250 °C, and carrying out a catalytic cracking reaction under the catalytic conditions of the cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomers, and separating and recovering it through separation operations. At the same time, high-boiling compounds are continuously introduced during the reaction.

[0025] Wherein, the mass ratio between the cracking catalyst and the high-boiling compound is 0.1-30:100.

[0026] Wherein, the cracking reaction temperature is 100-250 °C.

[0027] Wherein, the cracking agent is one or more of methyl chloride and hydrogen chloride.

[0028] Wherein, the reactor can be one of a packed tower, a fixed bed, a fluidized bed, a stirred bed, or a stirred reaction kettle.

[0029] High-boiling silicone compounds refer to high-boiling by-products generated during the production of silicone. These substances are usually generated during the synthesis of silicone monomers and have relatively high boiling points. The high-boiling silicone compounds in the following examples are provided by Xingrui Silicone Materials Co., Ltd. of Xingfa Group.

[0030] The present invention selects an organic amine containing hydroxyl groups. Because it contains hydroxyl groups (-OH), it can react with various substances containing silicon-chlorine bonds (Si-Cl) in the high-boiling silicone compound and graft it onto the high-boiling silicone compound.

[0031] The following embodiments are some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by the inventors based on the embodiments in the present invention without creative efforts belong to the protection scope of the present invention.

[0032] Example 1 The organosilicon high-boiling residue and N,N-bis(2-hydroxyethyl)ethylenediamine were added to a flask at a mass ratio of 2:1, heated to 130 °C and reacted for 1 hour to graft the hydroxyl-containing organic amine onto the organosilicon high-boiling residue to prepare a cracking catalyst.

[0033] 150 g of the organosilicon high-boiling residue was added to a packed column, and 9.00 g of the above-prepared cracking catalyst was added. Then, a cracking agent was introduced into the packed column, the flow rate of methyl chloride was 20 ml / min, the reaction temperature was controlled at 180 °C, and a catalytic cracking reaction occurred under the catalytic conditions of this cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which was separated and recovered by separation operations. At the same time, pretreated high-boiling residue was introduced at a flow rate of 6.70 g / min during the reaction for 30 min.

[0034] Calculated, the cracking rate of the organosilicon high-boiling residue can reach 80%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 70%.

[0035] Example 2 The organosilicon high-boiling residue and N,N-bis(2-hydroxyethyl)ethylenediamine were added to a flask at a mass ratio of 2:1, heated to 130 °C and reacted for 1 hour to graft the hydroxyl-containing organic amine onto the organosilicon high-boiling residue to prepare a cracking catalyst.

[0036] 150 g of the organosilicon high-boiling residue was added to a packed column, and 4.50 g of the above-prepared cracking catalyst was added. Then, a cracking agent was introduced into the packed column, the flow rate of methyl chloride was 20 ml / min, the reaction temperature was controlled at 165 °C, and a catalytic cracking reaction occurred under the catalytic conditions of this cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which was separated and recovered by separation operations. At the same time, pretreated high-boiling residue was introduced at a flow rate of 6.70 g / min during the reaction for 30 min.

[0037] Calculated, the cracking rate of the organosilicon high-boiling residue can reach 71%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 78%.

[0038] Example 3 The organosilicon high-boiling residue and N,N-bis(2-hydroxyethyl)ethylenediamine were added to a flask at a mass ratio of 2:1, heated to 130 °C and reacted for 1 hour to graft the hydroxyl-containing organic amine onto the organosilicon high-boiling residue to prepare a cracking catalyst.

[0039] Add 150 g of organosilicon high-boiling residues to a packed column, and add 2.25 g of the above-prepared cracking catalyst. Then, introduce a cracking agent into the packed column. The flow rate of methyl chloride is 20 ml / min. Control the reaction temperature at 150 °C. Under the catalytic conditions of this cracking catalyst, a catalytic cracking reaction occurs to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction process, introduce pretreated high-boiling residues at a flow rate of 6.70 g / min for 30 min.

[0040] Through calculation, the cracking rate of organosilicon high-boiling residues can reach 61%. Through gas chromatography detection, the selectivity of dimethyldichlorosilane can reach 79%.

[0041] Example 4 Add organosilicon high-boiling residues and N-(2-hydroxypropyl)ethylenediamine to a flask at a mass ratio of 2:1, heat to 130 °C and react for 1 hour to graft the hydroxy-containing organic amine onto the organosilicon high-boiling residues to prepare a cracking catalyst.

[0042] Add 150 g of organosilicon high-boiling residues to a packed column, and add 9.00 g of the above-prepared cracking catalyst. Then, introduce a cracking agent into the packed column. The flow rate of methyl chloride is 20 ml / min. Control the reaction temperature at 180 °C. Under the catalytic conditions of this cracking catalyst, a catalytic cracking reaction occurs to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction process, introduce pretreated high-boiling residues at a flow rate of 6.70 g / min for 30 min.

[0043] Through calculation, the cracking rate of organosilicon high-boiling residues can reach 67%. Through gas chromatography detection, the selectivity of dimethyldichlorosilane can reach 65%.

[0044] Example 5 Add organosilicon high-boiling residues and 2-(dimethylamino)ethanol to a flask at a mass ratio of 2:1, heat to 130 °C and react for 1 hour to graft the hydroxy-containing organic amine onto the organosilicon high-boiling residues to prepare a cracking catalyst.

[0045] Add 150 g of organosilicon high-boiling residues to a packed column, and add 9.00 g of the above-prepared cracking catalyst. Then, introduce a cracking agent into the packed column. The flow rate of methyl chloride is 20 ml / min. Control the reaction temperature at 180 °C. Under the catalytic conditions of this cracking catalyst, a catalytic cracking reaction occurs to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction process, introduce pretreated high-boiling residues at a flow rate of 6.70 g / min for 30 min.

[0046] Through calculation, the cracking rate of organosilicon high-boiling residues can reach 61%. Through gas chromatography detection, the selectivity of dimethyldichlorosilane can reach 53%.

[0047] Example 6 Add the silicone high-boiling residues and 2-methylaminoethanol into a flask at a mass ratio of 2:1, heat to 130 °C and react for 1 hour to graft the hydroxyl-containing organic amine onto the silicone high-boiling residues to prepare a cracking catalyst.

[0048] Add 150 g of silicone high-boiling residues into a packed column, and add 9.00 g of the cracking catalyst prepared above. Then introduce a cracking agent into the packed column. The flow rate of methyl chloride is 20 ml / min, control the reaction temperature at 180 °C, and carry out a catalytic cracking reaction under the catalytic conditions of this cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomer, and separate and recover it through separation operations. At the same time, introduce pretreated high-boiling residues at a flow rate of 6.70 g / min during the reaction for 30 min.

[0049] Calculated, the cracking rate of the silicone high-boiling residues can reach 53%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 51%.

[0050] Example 7 Add the silicone high-boiling residues and N,N-bis(2-hydroxyethyl)ethylenediamine into a flask at a mass ratio of 0.5:1, heat to 130 °C and react for 1 hour to graft the hydroxyl-containing organic amine onto the silicone high-boiling residues to prepare a cracking catalyst.

[0051] Add 150 g of silicone high-boiling residues into a packed column, and add 4.50 g of the cracking catalyst prepared above. Then introduce a cracking agent into the packed column. The flow rate of methyl chloride is 20 ml / min, control the reaction temperature at 180 °C, and carry out a catalytic cracking reaction under the catalytic conditions of this cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomer, and separate and recover it through separation operations. At the same time, introduce pretreated high-boiling residues at a flow rate of 6.70 g / min during the reaction for 30 min.

[0052] Calculated, the cracking rate of the silicone high-boiling residues can reach 71%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 63%.

[0053] Example 8 Add the silicone high-boiling residues and N,N-bis(2-hydroxyethyl)ethylenediamine into a flask at a mass ratio of 2:1, heat to 130 °C and react for 1 hour to graft the hydroxyl-containing organic amine onto the silicone high-boiling residues to prepare a cracking catalyst.

[0054] Add 150 g of organosilicon high boilers to a packed column, and add 9.00 g of the above-prepared cracking catalyst. Then, introduce a cracking agent into the packed column with a hydrogen chloride flow rate of 20 ml / min, control the reaction temperature at 180 °C, and carry out a catalytic cracking reaction under the catalytic conditions of this cracking catalyst to produce a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction, introduce pretreated high boilers at a flow rate of 6.70 g / min for 30 min.

[0055] Calculated, the cracking rate of organosilicon high boilers can reach 79%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 51%.

[0056] Example 9 Add organosilicon high boilers and N,N-bis(2-hydroxyethyl)ethylenediamine to a flask at a mass ratio of 2:1, heat to 130 °C and react for 1 hour to graft the hydroxy-containing organic amine onto the organosilicon high boilers to prepare a cracking catalyst.

[0057] Add 150 g of organosilicon high boilers to a fixed bed, and add 9.00 g of the above-prepared cracking catalyst. Then, introduce a cracking agent into the fixed bed with a methyl chloride flow rate of 20 ml / min, control the reaction temperature at 180 °C, and carry out a catalytic cracking reaction under the catalytic conditions of this cracking catalyst to produce a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction, introduce pretreated high boilers at a flow rate of 6.70 g / min for 30 min.

[0058] Calculated, the cracking rate of organosilicon high boilers can reach 73%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 67%.

[0059] Example 10 Add 150 g of organosilicon high boilers to a packed column, and add 3.00 g of N,N-bis(2-hydroxyethyl)ethylenediamine. Then, introduce a cracking agent into the packed column with a methyl chloride flow rate of 20 ml / min, control the reaction temperature at 180 °C, and carry out a catalytic cracking reaction under the catalytic conditions of this cracking catalyst to produce a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered through separation operations. At the same time, during the reaction, introduce pretreated high boilers at a flow rate of 6.70 g / min for 30 min.

[0060] Calculated, the cracking rate of organosilicon high boilers can reach 60%. Detected by a gas chromatograph, the selectivity of dimethyldichlorosilane can reach 57%.

Claims

1. A method for preparing a hydroxyl-containing organic amine grafted organosilicon high boiling point catalyst, characterized in that: The following steps are involved: The hydroxyl-containing organic amine is added into the high-boiling organosilicon and heated to make the hydroxyl-containing organic amine grafted onto the high-boiling organosilicon to prepare a cracking catalyst.

2. The process for preparing a hydroxyl-containing organic amine grafted organosilicon high boiling point catalyst according to claim 1, characterized in that: The mass ratio of the high boiling organosilicon substance to the organic amine is 0.5-5:

1.

3. The process for preparing a hydroxyl-containing organic amine grafted organosilicon high boiling point catalyst according to claim 1, characterized in that: The preparation temperature of the grafted cracking catalyst is 100-150°C.

4. The method for preparing a hydroxyl-containing organic amine grafted organosilicon high boiling point catalyst according to claim 1, characterized in that: The organic amine containing hydroxyl groups includes one or more combinations of N,N-bis(2-hydroxyethyl)ethylenediamine, N-(2-hydroxypropyl)ethylenediamine, 2-(dimethylamino)ethanol or 2-methylaminoethanol.

5. The method for preparing the hydroxyl-containing organic amine grafted organosilicon high boiling point catalyst according to any one of claims 1 to 4, characterized in that: In the prepared cracking catalyst, the small molecular hydroxyl-containing organic amine is grafted onto the high-boiling organic silicon in the form of covalent bonds.

6. A catalytic cracking process for high-boiling organic silicon, characterized in that: The following steps are involved: Add the high-boiling organosilicon product to a reactor, and add the hydroxyl-containing organic amine grafted organosilicon high-boiling product catalyst according to any one of claims 1 to 4, then introduce or not introduce a cracking agent into the reactor, control the reaction temperature to 100-250° C., and cause a catalytic cracking reaction under the catalytic conditions of the cracking catalyst to generate a mixed product mainly composed of dimethyldichlorosilane monomer, which is separated and recovered by a separation operation, and at the same time, continuously introduce high-boiling products during the reaction.

7. The catalytic cracking process of high-boiling organic silicon according to claim 6, characterized in that: The mass ratio of the hydroxyl-containing organic amine grafted organic silicon high boiling point catalyst to the high boiling point is 0.1-30:

100.

8. The catalytic cracking process of high-boiling organic silicon according to claim 6, characterized in that: The cracking reaction temperature is 100~250℃.

9. The catalytic cracking process of high-boiling organic silicon according to claim 6, characterized in that: The cracking agent is one or more of methyl chloride and hydrogen chloride.

10. The process for catalytic cracking of high-boiling organic silicon according to claim 6, characterized in that: The reactor can be one of a packed tower, a solidified bed, a fluidized bed, a stirred bed or a stirred reactor.

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