阅读说明：本技术 利用有机硅单体三甲氧基硅烷生产中的废触体制备铜基复合催化剂的方法及用途 (Method for preparing copper-based composite catalyst by using waste contact in production of organosilicon monomer trimethoxy silane and application ) 是由 苏发兵 李琼光 纪永军 谭强强 于 2019-10-11 设计创作，主要内容包括：本发明提供了一种利用有机硅单体三甲氧基硅烷生产中的废触体制备铜基复合催化剂的方法及用途,所述方法包括以下步骤：1)将含有机溶剂的废触体浆液,搅拌混合；2)将废触体浆液静置沉降后,去除上层清液以及下层的硅粉,分离得到含铜组分；3)将分离得到的含铜组分依次经过干燥和焙烧,得到铜基复合催化剂。本发明的优点在于：解决了三甲氧基硅烷生产中废触体的综合利用问题；原料废触体成本低廉、操作流程简单、易于工业化大规模生产。采用本发明制备的铜基复合催化剂一次颗粒的粒径小,疏松多孔,且重现性好；将其重新用于三甲氧基硅烷单体合成反应中,与商业催化剂相比,表现出更高的三甲氧基硅烷选择性和甲醇转化率。(The invention provides a method for preparing a copper-based composite catalyst by using a waste contact body in the production of organosilicon monomer trimethoxy silane and application thereof, wherein the method comprises the following steps: 1) stirring and mixing the waste contact body slurry containing the organic solvent; 2) after the waste contact body slurry is kept stand and settled, removing supernatant liquid and silicon powder on the lower layer, and separating to obtain a copper-containing component; 3) and drying and roasting the separated copper-containing component in sequence to obtain the copper-based composite catalyst. The invention has the advantages that: the problem of comprehensive utilization of waste contacts in production of trimethoxy silane is solved; the waste contact body of the raw material has low cost and simple operation flow and is easy for industrialized mass production. The copper-based composite catalyst prepared by the method has small primary particle size, is loose and porous and has good reproducibility; the trimethoxy silane catalyst is reused in the synthesis reaction of trimethoxy silane monomers, and shows higher selectivity of trimethoxy silane and conversion rate of methanol compared with a commercial catalyst.)

1. A method for preparing a copper-based composite catalyst by using a waste contact body in the production of organosilicon monomer trimethoxy silane is characterized by comprising the following steps:

1) stirring and mixing the waste contact body slurry containing the organic solvent;

2) standing and settling the waste contact body slurry obtained in the step 1), removing supernatant liquid and silicon powder on the lower layer, and separating to obtain a copper-containing component;

3) and (3) drying and roasting the copper-containing component obtained by separation in the step 2) in sequence to obtain the copper-based composite catalyst.

2. The method according to claim 1, wherein the waste contact body in the step 1) is solid waste residue generated by preparing organosilicon monomer trimethoxy silane by a direct method process;

preferably, the particle size of the waste contact body is 0.05-20 μm.

3. The method according to claim 1 or 2, wherein the organic solvent in step 1) comprises any one or a combination of at least two of methanol, ethanol, ethylene glycol, propanol, glycerol, benzene, toluene, xylene, phenyl ether or xylyl ether, further preferably methanol and/or ethanol, and most preferably methanol;

preferably, the mass ratio of the organic solvent to the solid in the waste contact body slurry is 0.5-10: 1;

preferably, the mixing temperature in the step 1) is 15-50 ℃.

4. A method according to any one of claims 1-3, wherein the standing time in step 2) is 2-96 h, more preferably 6-48 h, most preferably 12-36 h.

5. The method according to any one of claims 1 to 4, wherein the drying method of step 3) is forced air drying or vacuum drying;

preferably, the temperature of the forced air drying is 200-400 ℃, and further preferably 300-350 ℃;

preferably, the temperature of the vacuum drying is 30-220 ℃, and further preferably 180-220 ℃;

preferably, the atmosphere for the calcination in step 3) is air or oxygen, preferably air;

preferably, the roasting temperature is 300-900 ℃, more preferably 600-800 ℃, and most preferably 700-800 ℃;

preferably, the roasting time is 5-300 min, more preferably 5-90 min, and most preferably 30-60 min;

preferably, the roasting apparatus comprises any one of a tube furnace, a box furnace, a muffle furnace, a rotary kiln, a fixed bed or a fluidized bed, preferably a muffle furnace.

6. The method according to any one of claims 1 to 5, wherein the firing of step 3) is followed by ball milling;

preferably, the ball-milled beads comprise any one of steel, agate, zirconia or alumina balls:

preferably, the mass ratio of the ball-milled beads to the brown solid matter is 1-30: 1, more preferably 5-15: 1, and most preferably 10-15: 1;

preferably, the ball milling time is 0-120 min, more preferably 20-60 min, and most preferably 30-50 min;

preferably, the rotation speed of the ball mill is 100-1000 rpm, more preferably 400-800 rpm, and most preferably 600-700 rpm.

7. The process of any one of claims 1-6, further comprising recycling the separated silicon powder.

8. The method according to any one of claims 1-7, characterized in that the method comprises the steps of:

1) immersing the waste contact body into methanol, fully stirring and mixing to obtain waste contact body slurry, wherein the mass ratio of the methanol to the solid in the waste contact body slurry is 0.5-10: 1, and the mixing temperature is 15-50 ℃;

2) standing and settling the slurry obtained in the step 1), wherein the standing time is 2-96 hours, pouring supernatant liquor, then separating brown slurry from silicon powder precipitate at the bottom, and centrifuging the brown slurry to obtain brown solid, wherein the brown solid is a copper-containing component;

3) and (3) sequentially carrying out vacuum drying at 30-220 ℃, roasting at 300-900 ℃ for 5-300 min on the brown solid in the step 2), and then carrying out ball milling at the rotating speed of 100-1000 rpm for 20-60 min to obtain the copper-based composite catalyst.

9. Copper-based composite catalyst prepared according to any one of claims 1 to 8, characterized in that the components of the catalyst comprise copper silicide, copper oxide and silicon;

preferably, the catalyst is in a loose porous form;

preferably, the catalyst is formed by stacking primary particles to form secondary particles, and the particle size of the primary particles is 50-150 nm.

10. Use of the copper-based composite catalyst prepared by the method according to any one of claims 1 to 8 or the copper-based composite catalyst according to claim 9, wherein the copper-based composite catalyst is used in an organosilicon monomer synthesis reaction.

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to a method for preparing a copper-based composite catalyst by using a waste contact body in the production of an organosilicon monomer trimethoxy silane and application thereof.

Background

The organosilicon monomer trimethoxy silane (M3) is an important raw material for synthesizing silane coupling agent, organosilicon terminated polyether, polyacrylate sealing glue and adhesive in organosilicon industry, and has important application value. Currently, trimethoxy silane is industrially synthesized by a direct method, namely silicon powder and methanol are directly reacted under the action of a copper-based catalyst to obtain (CN 106243145A), and the reaction formula is as follows:

Si+CH₃OH→HSi(OCH₃)₃+H₂

compared with the traditional method for preparing trimethoxy silane by reacting trichlorosilane with methanol, the method has the greatest advantages that HCl is not generated in the reaction process, equipment is not corroded, and meanwhile, the pollution to the environment is reduced. However, this reaction produces trimethoxysilane with the concomitant production of a number of by-products including dimethoxydihydrosilane, methyltrimethoxysilane, tetramethoxysilane, siloxane polymers, and the like. In recent years, with the rapid development of the organosilicon industry, the market demand for trimethoxy silane is increased, so that the improvement of the selectivity of synthesizing trimethoxy silane by a direct method and the reduction of the production cost are particularly important.

On the other hand, due to the limitation of the existing process and reaction kinetics, a large amount of industrial waste residues, namely waste contact bodies in the production of the trimethoxy silane, is generated in the production process of the trimethoxy silane. The main components of the waste contact body are silicon and copper, and the contents of the silicon and the copper are respectively 70% -95% and 4% -29%. The copper component in the waste contact body has low catalytic activity and cannot be directly utilized in the synthesis reaction of trimethoxy silane. With the increasing production scale of organosilicon coupling agent, the amount of waste contact body produced is also increasing, so that the development of a method for efficiently recovering waste contact body in the production of trimethoxy silane and realizing high-value utilization thereof is urgently needed, and the significance is that: (1) the pollution of industrial waste residue to the environment is reduced; (2) the utilization rate of raw materials is improved.

Patent CN103555951A discloses a method for extracting copper oxide from waste materials generated in the production of methylchlorosilane, which solves the problem of copper recovery in the production process of organosilicon through complicated operation processes such as grinding, oxidation, acidification, alkali neutralization, filtration, replacement, drying, etc. Patent CN104451162A discloses a process for extracting copper from waste contacts generated in the production of methylchlorosilane, which comprises the steps of acid washing, oxidation, filtration, replacement, alkali neutralization, filtration, drying and the like. Patent CN102795653A discloses a method for extracting and recovering copper oxide and zinc oxide from waste contact bodies generated in the production of methylchlorosilane, which still does not completely solve the problem of efficient recovery and utilization of waste contact bodies.

The above patents show that the recovery of the waste contacts from the production of methylchlorosilanes has attracted a great interest and has great application value. However, the compositions of waste contacts generated in different production processes are different, the method is not suitable for recovering the waste contacts in the production of trimethoxy silane, and the recovered product cannot be used as a high-efficiency catalyst. There is no published report on the method for recycling waste contact bodies in the production of trimethoxy silane.

Therefore, we propose a method for preparing a high-activity copper-based composite catalyst by recycling waste contact bodies in the production of trimethoxy silane.

Disclosure of Invention

In order to solve the above problems in the prior art, an object of the present invention is to provide a method for preparing a copper-based composite catalyst from waste contacts in the production of an organosilicon monomer trimethoxysilane, wherein the method uses recycled industrial waste residues and waste contacts as raw materials to prepare a high-performance copper-based composite catalyst through simple operations, and the method is suitable for direct synthesis of trimethoxysilane.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a copper-based composite catalyst by using a waste contact body in the production of organosilicon monomer trimethoxy silane is characterized by comprising the following steps:

1) stirring and mixing the waste contact body slurry containing the organic solvent;

2) standing and settling the waste contact body slurry obtained in the step 1), removing supernatant and silicon powder precipitate at the lower layer, and separating to obtain a copper-containing component;

3) and (3) drying and roasting the copper-containing component obtained by separation in the step 2) in sequence to obtain the copper-based composite catalyst.

In the production process of trimethoxy silane, because of the limitation of the existing process and reaction kinetics, a large amount of industrial waste residue is generated, which is called waste contact in the production of trimethoxy silane. The main components of the waste contact body are silicon and copper, the silicon content is 70 wt% to 95 wt%, such as 70 wt%, 72 wt%, 75 wt%, 80 wt%, 90 wt% or 95 wt%, etc., and the copper content is 4 wt% to 29 wt%, such as 4 wt%, 8 wt%, 12 wt%, 15 wt%, 20 wt%, 25 wt% or 28 wt%, etc. The copper component in the waste contact body has low catalytic activity and cannot be directly utilized in the synthesis reaction of trimethoxy silane.

In the waste contact body in the production of the trimethoxy silane, silicon and copper are main components and account for more than 99 percent of the total content, and the rest trace carbon and silicon have two forms, namely unreacted raw silicon powder (the particle size is about 75 mu m), and fine particle silicon which has close action with the active component of the waste contact body in the reaction process and has the particle size of about 500 nm.

The "waste contact body slurry containing an organic solvent" according to the present invention may be a slurry produced in a production process under liquid phase conditions, which contains waste contact bodies, unreacted silicon powder and a solvent (such as phenylene ether); it is also possible to form a slurry of the waste contacts by immersing the solid waste contacts in an organic solvent, also containing unreacted silicon powder.

The method for separating the copper-containing component in step 2) of the present invention may be, for example, pouring out the supernatant, then pouring out the brown slurry in the middle layer to separate the brown slurry from the unreacted silica powder in the bottom layer, and then centrifuging the brown slurry to obtain the copper-containing component.

The invention sequentially passes through the processes of separation, roasting and ball milling, and extracts and activates copper-containing components from waste contact bodies in the production of trimethoxy silane to prepare the high-activity copper-based composite catalyst. Preferably, the stirring in the step 1) is fully stirred to fully separate the components of the waste contact body, the silicon powder and the copper-containing component (fine particle silicon is combined with the copper-containing component in the copper-containing component) are separated, the mixture is settled by standing by utilizing the difference of the densities of the solvent, the silicon powder and the copper-containing component, the layering occurs after a certain time, the upper layer is transparent liquid, the middle layer is brown copper-based composite catalyst precursor (namely copper-containing component), and the lower layer is unreacted metal silicon powder. After the drying and roasting in the step 2), the copper-containing component is oxidized, and the activation is realized in the ball milling process on one hand, and the compound has a loose porous structure on the other hand, so that the copper-based composite catalyst with high activity is prepared.

The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.

Preferably, the waste contact body in the step 1) is solid waste residue generated by preparing organosilicon monomer trimethoxy silane by a direct method process.

Preferably, the particle size of the waste contact is 0.05 to 20 μm, such as 0.05 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm.

Preferably, the organic solvent of step 1) comprises any one or a combination of at least two of methanol, ethanol, ethylene glycol, propanol, glycerol, benzene, toluene, xylene, phenyl ether, and xylyl ether, and typical but non-limiting examples of the combination are: a combination of methanol and ethanol, methanol, ethanol and ethylene glycol, ethanol, ethylene glycol, propanol and glycerol, benzene, toluene, xylene and phenyl ether, ethanol, propanol, benzene, and the like. Further preferred is methanol and/or ethanol, and most preferred is methanol. However, the organic solvent is not limited to the above-mentioned ones, and other organic solvents commonly used in the art to achieve the same effects can be used in the present invention.

Preferably, the mass ratio of organic solvent to solid in the spent contact slurry is 0.5 to 10:1, such as 0.5:1, 1:1, 2:1, 3:1, 4.5:1, 5:1, 6:1, 7:1, 8:1, or 10: 1. If the mass ratio is less than 0.5:1, the solid matters are difficult to settle; if the mass ratio is more than 10:1, waste of the organic solvent is caused.

Preferably, the temperature of the mixing in step 1) is 15 to 50 ℃, for example, 15 ℃, 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃ or 50 ℃.

Preferably, the standing time in the step 2) is 2-96 h, such as 2h, 6h, 12h, 18h, 24h, 30h, 36h, 48h, 60h, 72h, 84h, 96h, more preferably 6-48 h, and most preferably 12-36 h.

Preferably, the drying method in step 3) is air blast drying or vacuum drying.

Preferably, the temperature of the air-blast drying is 200 to 400 ℃, for example, 200 ℃, 220 ℃, 240 ℃, 260 ℃, 280 ℃, 300 ℃, 320 ℃, 340 ℃, 360 ℃, 380 ℃ or 400 ℃, and more preferably 300 to 350 ℃.

Preferably, the vacuum drying temperature is 30-220 ℃, such as 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃ or 220 ℃, further preferably 180-220 ℃;

preferably, the atmosphere for the calcination in step 3) is air or oxygen, preferably air;

preferably, the baking temperature is 300 to 900 ℃, such as 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃ or 900 ℃. The carbon is converted into gaseous state for volatilization and the conversion from Cu to copper oxide is achieved by roasting, and in order to achieve the better effect, the temperature is more preferably 600-800 ℃, and the most preferably 700-800 ℃.

Preferably, the roasting time is 5-300 min, such as 5min, 10min, 15min, 20min, 25min, 30min, 40min, 50min, 70min, 90min, 100min, 140min, 180min, 200min, 250min or 300min, etc., more preferably 5-90 min, and most preferably 30-60 min;

preferably, the roasting apparatus comprises any one of a tube furnace, a box furnace, a muffle furnace, a rotary kiln, a fixed bed or a fluidized bed, preferably a muffle furnace.

Preferably, the calcination of step 3) is followed by ball milling.

Preferably, the ball-milled beads comprise any one of steel, agate, zirconia or alumina balls:

preferably, the mass ratio of the ball-milled beads to the brown solid (i.e., the ball-to-material ratio) is 1 to 30:1, for example, 1:1, 5:1, 10:1, 15:1, 20:1, 25:1, or 30:1, etc., more preferably 5 to 15:1, and most preferably 10 to 15: 1;

preferably, the ball milling time is 0-120 min, such as 0min, 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min or 120min, etc., more preferably 20-60 min, and most preferably 30-50 min.

Preferably, the rotation speed of the ball mill is 100 to 1000rpm, such as 100rpm, 200pm, 300rpm, 400rpm, 500rpm, 600rpm, 700rpm, 800rpm, 900rpm or 1000rpm, etc., more preferably 400 to 800rpm, and most preferably 600 to 700 rpm.

Through the control of the ball-to-material ratio and the ball-milling time in the ball milling, the product morphology can be optimized, small particles are adhered to form a porous state, and the formed adhered small particles are scattered if the ball-milling time is too long.

The invention can also include recycling the separated silicon powder, for example, drying the silicon powder and recycling the dried silicon powder as the raw material.

As a further preferred technical solution of the method of the present invention, the method comprises the steps of:

1) immersing the waste contact body into methanol, fully stirring and mixing to obtain waste contact body slurry, wherein the mass ratio of the methanol to the solid in the waste contact body slurry is 0.5-10: 1, and the mixing temperature is 15-50 ℃;

2) standing and settling the slurry obtained in the step 1), wherein the standing time is 2-96 hours, pouring supernatant liquor, then separating brown slurry from silicon powder precipitate at the bottom, and centrifuging the brown slurry to obtain brown solid, wherein the brown solid is a copper-containing component;

3) and (3) sequentially carrying out vacuum drying at 30-220 ℃, roasting at 300-900 ℃ for 5-300 min on the brown solid in the step 2), and then carrying out ball milling at the rotating speed of 100-1000 rpm for 20-60 min to obtain the copper-based composite catalyst.

The second purpose of the invention is to provide a copper-based composite catalyst prepared by the method, and the components of the catalyst comprise copper silicide, copper oxide and silicon.

The catalyst of the invention contains a certain amount of copper silicide and silicon instead of pure component copper oxide, and the two components are closely related to the composition of a waste contact body in the production of trimethoxy silane.

Preferably, the catalyst is in the form of loose porosity.

Preferably, the catalyst is formed by stacking primary particles having a particle size of 50 to 150nm, such as 50nm, 75nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, etc., to form secondary particles.

The invention also aims to provide the copper-based composite catalyst prepared by the method or the application of the copper-based composite catalyst, and the copper-based composite catalyst is used for organosilicon monomer synthesis reaction and promotes selective synthesis of trimethoxy silane.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention provides a method for preparing a copper-based composite catalyst by using a waste contact body in the production of an organosilicon monomer trimethoxy silane. Wherein, unreacted metal silicon powder and copper-containing components are separated out by cleaning of an organic solvent, and the copper-containing components are roasted and ball-milled for a certain time to prepare the high-activity copper-based composite catalyst.

(2) The method has simple recovery flow, and solves the problem of comprehensive utilization of waste contact bodies in the production of the trimethoxy silane; the cost of the waste contact body of the raw material is low, the operation flow is simple, the direct recycling of the waste contact body is realized, and the industrial large-scale production is easy to realize.

(3) The copper-based composite catalyst prepared by the invention has small particle size of primary particles, is loose and porous and has good reproducibility; the catalyst is reused for catalyzing the selective synthesis of trimethoxy silane, and compared with a commercial catalyst, the catalyst has the characteristics of high trimethoxy silane selectivity, high methanol conversion rate and the like.

Drawings

FIG. 1a is a schematic diagram of an apparatus for synthesizing trimethoxysilane by a direct method in example 1 of the present invention;

FIG. 1b is a photograph of the product of example 1 of the present invention before and after sedimentation;

FIG. 2 is an XRD pattern of a copper-based composite catalyst prepared in example 1 of the present invention;

FIG. 3 is an SEM image of a copper-based composite catalyst prepared in example 1 of the present invention.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the present invention, which is defined by the claims.