Method for preparing supported copper-based catalyst by using sectional continuous flow technology

Abstract

The invention belongs to the technical field of catalyst continuous flow method preparation, and particularly relates to a method for preparing a supported copper-based catalyst by using a sectional continuous flow technology. The sectional continuous flow method has the advantages of automatic continuous production, accurate control of reaction conditions, uniform mixing of materials, reduction of personal errors and the like, and effectively solves the problems of long time consumption, easy non-uniform mixing, poor repeatability and the like of an impregnation method. Secondly, the active carbon serves as a carrier, copper serves as a main active component, ethyl alcohol serves as a solvent, the sectional type continuous flow technology is utilized, the particle size of copper species is regulated and controlled by adjusting the gas flow rate, the copper-based catalyst which is evenly distributed, small in particle size and high in activity is prepared, the production efficiency of the catalyst is improved, and meanwhile the catalyst yield is increased. And the catalytic performance of the catalyst in the reaction of preparing vinyl chloride from acetylene and hydrogen chloride is optimized.

Description

Technical Field

[0001] The present invention belongs to the technical field of continuous flow preparation of catalysts, and specifically relates to a method for preparing a supported copper-based catalyst using segmented continuous flow technology. The catalyst uses activated carbon as a carrier, copper as a main active component, and ethanol as a solvent. The segmented continuous flow technology is used to adjust the particle size of the copper species by adjusting the gas flow rate, so as to prepare a copper-based catalyst with uniform distribution, small particle size, and high activity. While improving the production efficiency of the catalyst, the catalytic performance in the reaction of acetylene hydrogen chloride to vinyl chloride is optimized. At the same time, the segmented continuous flow preparation method is adopted, which not only realizes automated continuous production, but also can accurately control the reaction flow rate, evenly mix materials, reduce human errors, and has significant industrial application potential. Background Art

[0002] As an innovative reaction technology, the core purpose of the continuous flow reactor is to significantly improve the continuity of chemical reactions. The narrow channel inside this reactor has an inner diameter that is finely controlled between microns and millimeters, providing a unique reaction environment for chemical reactions. Continuous flow technology has the characteristics of high mass and heat transfer efficiency, precise controllable reaction parameters, good reaction repeatability, and a high degree of integrated automation. In recent years, continuous flow reactors have attracted much attention due to their many advantages, and their application areas are becoming increasingly extensive. At present, they are mainly used in the fields of organic synthesis, preparation of nanomaterials and nanoparticles, etc., providing an efficient and stable reaction platform for scientific research and industrial production, and promoting the rapid development of related fields.

[0003] Polyvinyl chloride (PVC) is a widely used general-purpose plastic that plays an irreplaceable role in many fields such as construction, medical equipment, electronic products, and transportation facilities. PVC is made by the polymerization of vinyl chloride monomer (VCM). There are three main preparation processes for VCM: acetylene hydrochlorination, ethylene oxychlorination, and ethane. In view of the particularity of my country's energy structure, that is, abundant coal resources and relatively scarce oil resources, the acetylene hydrochlorination method has occupied a dominant position in my country due to its advantages such as easy availability of raw materials and mature technology. However, the industrial application of the acetylene hydrochlorination method is currently highly dependent on mercuric chloride (HgCl 2 / AC) catalyst. Although mercuric chloride shows excellent activity in the catalytic process, its highly toxic and easy sublimation characteristics pose a great threat to the environment and human health. In addition, the scarcity of global mercury resources has also exacerbated the urgency of this issue, making the search for alternative catalysts a top priority. The development of a new, green, and efficient mercury-free catalyst is of vital importance for my country to achieve green and sustainable development of the polyvinyl chloride industry. This will not only help reduce mercury pollution, but also promote the transformation and upgrading of the PVC industry and enhance its competitiveness in the international market.

[0004] Mercury-free catalysts can be roughly divided into two categories: supported metal catalysts and non-metallic catalysts. Among them, non-precious metal catalysts are regarded as an ideal alternative to mercury-based catalysts due to their significant advantages such as low cost, high activity and strong stability. In the laboratory research and development stage, researchers usually use the incipient wetness impregnation method (IWI) to synthesize copper-based catalysts in small batches. However, when entering the industrial production stage, batch reactors are often used for large-scale synthesis. This method often leads to large copper species particles and uneven distribution, which in turn has an adverse effect on the overall performance of the catalyst. In addition, the particle size and particle size distribution of copper species directly determine the number of active sites, which is one of the key factors affecting the activity of the catalyst. Therefore, exploring a catalyst synthesis method that is simple and easy to scale up, while ensuring high activity at multiple sites is of vital importance to promote the industrial application of mercury-free catalysts. Summary of the invention

[0005] The present invention provides a method for preparing a supported copper-based catalyst using a segmented continuous flow technology. By using the segmented continuous flow method, the particle size of the copper species is regulated by adjusting the gas flow rate, and a copper-based catalyst with uniform distribution, small particle size and high activity is prepared simply and efficiently. -1 , V(C 2 H 2 ) / V(HCl)=1:1.05, under the condition of reaction temperature of 180℃, the acetylene conversion rate reached 76.2%, VCM selectivity was greater than 99.9%, and each segmented continuous flow device could produce 311 g / d of copper-based catalyst.

[0006] In order to solve the technical problem of the present invention, a technical solution is proposed: a method for preparing a supported copper-based catalyst using a segmented continuous flow technology, comprising the following steps:

[0007] (1) Prepare copper precursor solution: weigh 3473 mg of copper chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 ·2H 2 O is completely dissolved to obtain a copper precursor solution;

[0008] (2) Weighing 3000 mg of activated carbon into a container, adding an appropriate amount of anhydrous ethanol for ultrasonic dispersion to obtain an activated carbon slurry; the volume ratio of anhydrous ethanol used to prepare the activated carbon slurry and the copper precursor solution in steps (1) and (2) is 2:1, and the activated carbon is coconut shell activated carbon;

[0009] (3) Preparation of copper-based catalyst using a segmented continuous flow device:

[0010] The segmented continuous flow device is composed of a magnetic stirrer (2), a nitrogen bottle (4), a peristaltic pump (5), a polypropylene tee (6), a nitrogen flow meter (7), a polytetrafluoroethylene pipeline (8) and a collection device (9);

[0011] The inlet end pipeline of the peristaltic pump (5) is respectively introduced into the beaker containing the activated carbon slurry (1) and the copper precursor solution (3), and the liquid is sucked into the pipeline through the peristaltic pump (5) and mixed at the first polypropylene tee (6); after flowing through a section of polytetrafluoroethylene pipeline, it merges with the gas flowing through the nitrogen flowmeter (7) at the second polypropylene tee to form a stable gas-liquid diversion section; the lower interface of the second polypropylene tee is connected to a section of polytetrafluoroethylene pipeline (8), and after waiting for a period of time, the mixed liquid is collected by a collecting device (9); the flow rate ratio of the activated carbon slurry, the copper precursor solution and the nitrogen in the preparation process of the segmented continuous flow technology is 2:1:13;

[0012] (4) placing the beaker containing the solid-liquid mixture in a water bath and heating it at 60° C. to volatilize the anhydrous ethanol, and finally drying the obtained solid in a forced air drying oven for 12-24 h. The mass ratio of copper to activated carbon in the catalyst is 20:80;

[0013] (5) The prepared copper-based catalyst is used in the reaction of acetylene hydrochloride to produce vinyl chloride.

[0014] The method for preparing a supported copper-based catalyst using a segmented continuous flow technology is characterized in that: the preparation method of the copper-based catalyst is as follows: weigh 3473 mg of copper chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 · 2 H 2 O was completely dissolved to obtain a copper precursor solution; 3000 mg of activated carbon was weighed and added to a container, and 90 mL of anhydrous ethanol was added for ultrasonic dispersion to obtain an activated carbon slurry; the inlet pipe of the peristaltic pump was introduced into the beakers containing the activated carbon slurry and the copper precursor solution, respectively, and the flow rate of the activated carbon slurry was set to 2 mL / min, and the flow rate of the copper precursor solution was set to 1 mL / min. The peristaltic pump switch was started at the same time, and the activated carbon slurry and the copper precursor solution were mixed at the first polypropylene tee; after flowing through a section of polytetrafluoroethylene pipe, it was mixed with N at a flow rate of 13 mL / min. 2The gases were mixed at the second polypropylene tee to form a stable gas-liquid segmented flow. After waiting for 30 minutes, a solid-liquid mixture of the copper-based catalyst was obtained. After the ethanol was evaporated by heating in a water bath, the beaker was placed in a 90°C forced air drying oven and dried for 12 hours. After drying, it was sealed and stored. The mass ratio of copper to activated carbon in the catalyst was 20:80, and the catalyst was named 20 wt.%Cu / AC-SMF. 13 .

[0015] The method for preparing a supported copper-based catalyst using segmented continuous flow technology is characterized in that: the gas in step (3) is N 2 In step (4), the solid-liquid mixture separation method is water bath heating at a heating temperature of 60°C.

[0016] The method for preparing a supported copper-based catalyst using segmented continuous flow technology is characterized in that the container and the collecting device are beakers, and the polytetrafluoroethylene pipeline connected to the lower interface of the second polypropylene tee is circularly wound.

[0017] The method for preparing a supported copper-based catalyst using a segmented continuous flow technology is characterized in that the acetylene hydrogen chloride to vinyl chloride reaction in step (5) is specifically performed as follows:

[0018] (1) Catalyst loading: Place a layer of quartz wool with a thickness of 10 mm in the middle of a quartz reaction tube with a diameter of 10 mm, add a certain amount of catalyst into the reaction tube and ensure that the catalyst is flat, and then place another layer of quartz wool with a thickness of 10 mm;

[0019] (2) Before the reaction: 2 The entire pipeline was purged at a flow rate of 20 mL / min for 60 min to remove air and moisture in the reaction system. At the same time, the temperature was raised to 150 °C at 5 °C / min and maintained for 30 min, and then the temperature was further raised to 180 °C at 5 °C / min. Then, HCl gas was introduced at a flow rate of 20 mL / min and maintained for 30 min, and then V C2H2 =16mL / min, V HCl =16.8 mL / min flow rate of the reaction gas and maintain for 10 min to ensure that the catalyst is in the gas atmosphere of acetylene and hydrogen chloride, and then V C2H2 / V HCl =1:1.05 ratio to reduce the reaction gas flow rate, at V C2H2 =4 mL / min, V HCl =4.2 mL / min reaction flow rate, maintained for 20 min, before starting detection;

[0020] (3) After the reaction: The gaseous product first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then was analyzed online by gas chromatography GC-9790Ⅱ to evaluate the acetylene conversion rate and VCM selectivity.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a segmented millifluidic flow method (SMF) for preparing a supported copper-based catalyst. Compared with the traditional impregnation method, this method achieves a significant reduction in preparation cost, greatly improves production efficiency and catalytic performance, effectively reduces human errors, is more convenient and efficient to operate, and supports continuous production mode. Compared with the continuous continuous flow method, this method further optimizes the mixing effect of copper species and activated carbon inside the droplets, effectively avoids the deposition problem of activated carbon in the pipeline, achieves uniform mixing of materials, ensures the uniform distribution of copper species particles on the surface of activated carbon, and can accurately control the size of copper species particles. First of all, this method uses a millimeter-level pipe diameter, which greatly increases the contact area of ​​the reaction liquid, and can quickly transfer mass and heat to achieve uniform mixing of materials.

[0023] Secondly, this method screened different gas flow rates and determined the activated carbon slurry, copper precursor solution, gas (N 2 ) was 2:1:13 mL / min, the copper-based catalyst prepared by the segmented continuous flow method had the best catalytic effect, with a conversion of 76.2% and a VCM selectivity of more than 99.9% in the acetylene hydrochlorination reaction.

[0024] Finally, the automated operation of the segmented continuous flow device can avoid human errors, ensure product quality, and greatly improve production efficiency. Each segmented continuous flow device can produce 311 g / d of copper-based catalyst. The present invention efficiently prepares copper-based catalyst (20 wt.%Cu / AC-SMF 13 ), significantly saving production costs, showing excellent catalytic performance in acetylene hydrochlorination reaction, and has the potential for industrial application.

[0025] As can be seen from Table 1, the catalyst 20 wt.% Cu / AC-SMF prepared by the segmented continuous flow method in Example 3 13 , at a reaction temperature of 180°C, GHSV (C 2 H 2 )=170 h -1 Under the optimal conditions, the acetylene conversion rate reached 76.2%, and the VCM selectivity was higher than 99.9%, which was the best activity. Compared with the acetylene conversion rate (64.0%) obtained by 20 wt.% Cu / AC-IWI prepared by impregnation method, it was increased by 12.2% (such asFigure 2-3 At the same time, Figure 4 It can be seen that Examples 3-4 prepared copper-based catalysts with loading amounts of 20% and 9%, indicating that the segmented continuous flow method can be used to prepare copper-based catalysts with different loading amounts, and the catalyst with a loading amount of 20% prepared in Example 3 has the best activity.

[0026] It can be seen from Table 2 that with the increase of gas flow rate, the volume of the liquid segment is smaller and the distribution is wider, and the copper species particles in the copper-based catalyst are smaller. When the activated carbon slurry flow rate is 2 mL / min, the copper precursor solution flow rate is 1 mL / min, and the gas flow rate is 13 mL / min, the catalyst 20 wt.%Cu / AC-SMF prepared in Example 3 has a 13 The copper species particles are evenly distributed, with the smallest particle size (3.90 ± 1.58 nm) and the best catalytic activity. Compared with the catalyst 20wt.%Cu / AC-IWI prepared by impregnation method (13.53 ± 4.70 nm), the particle size is reduced by about 9.63 nm (e.g. Figure 4-7 as shown). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the segmented continuous flow device.

[0028] Including: activated carbon slurry-1, magnetic stirrer-2, copper precursor solution-3, nitrogen bottle-4, peristaltic pump-5, polytetrafluoroethylene tee-6, nitrogen flowmeter-7, polytetrafluoroethylene pipeline-8, post-reaction mixed liquid-9.

[0029] Figure 2 For the catalyst (Examples 1-3, Comparative Example 1) at GHSV (C 2 H 2 )=170 h -1 The relationship between reaction time and acetylene conversion under different conditions.

[0030] Figure 3 For the catalyst (Examples 1-3, Comparative Example 1) at GHSV (C 2 H 2 )=170 h -1 Relationship between reaction time and VCM selectivity under different conditions.

[0031] Figure 4 For the catalyst (Example 3-4) at GHSV (C 2 H 2 )=170 h -1 The relationship between reaction time and acetylene conversion under different conditions.

[0032] Figure 5For the catalyst (Example 3-4) at GHSV (C 2 H 2 )=170 h -1 Relationship between reaction time and VCM selectivity under different conditions.

[0033] Figure 6 TEM and particle size distribution diagram of catalyst example 1.

[0034] Figure 7 TEM and particle size distribution diagram of catalyst comparative example 1.

[0035] Figure 8 TEM and particle size distribution diagram of catalyst example 2.

[0036] Fig. 9 TEM and particle size distribution diagram of catalyst example 3. DETAILED DESCRIPTION

[0037] Example 1 Catalyst Preparation

[0038] A copper-based catalyst is prepared using a segmented continuous flow device: the segmented continuous flow device is composed of a magnetic stirrer (2), a nitrogen bottle (4), a peristaltic pump (5), a polypropylene tee (6), a nitrogen flow meter (7), a polytetrafluoroethylene pipeline (8) and a collection device (9);

[0039] The inlet end pipeline of the peristaltic pump (5) is respectively introduced into the beaker containing the activated carbon slurry (1) and the copper precursor solution (3), and the liquid is sucked into the pipeline through the peristaltic pump (5) and mixed at the first polypropylene tee (6); after flowing through a section of polytetrafluoroethylene pipeline, it merges with the gas flowing through the nitrogen flow meter (7) at the second polypropylene tee to form a stable gas-liquid diversion section; the lower interface of the second polypropylene tee is connected to a section of polytetrafluoroethylene pipeline (8), and after waiting for a period of time, the mixed liquid is collected by a collecting device (9);

[0040] Preparation of catalyst by segmented continuous flow method: Weigh 3473 mg of cupric chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 ·2H 2 O was completely dissolved to obtain a copper precursor solution; 3000 mg coconut shell activated carbon (S BET = 1108 m 2 / g) was added into a container, and 90 mL of anhydrous ethanol was added for ultrasonic dispersion to obtain activated carbon slurry; the inlet pipe of the peristaltic pump was introduced into the beakers containing activated carbon slurry and copper precursor solution respectively, the flow rate of activated carbon slurry was set to 2 mL / min, and the flow rate of copper precursor solution was set to 1 mL / min, and the peristaltic pump switch was started at the same time, the activated carbon slurry and the copper precursor solution were mixed at the polypropylene tee, and after waiting for 30 minutes, a solid-liquid mixture of copper-based catalyst was obtained; after heating in a water bath at 60°C to volatilize ethanol, the beaker was placed in a 90°C forced air drying oven for 12 hours and then sealed for storage; the mass of copper:activated carbon in the catalyst was 20:80, and each segmented continuous flow device could produce 311 g / d of copper-based catalyst.

[0041] The catalyst was named 20 wt.%Cu / AC-SMF 0 .

[0042] Comparative Example 1 Catalyst Preparation

[0043] Weigh 3473 mg of copper chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 9 mL of anhydrous ethanol and the CuCl 2 ·2H 2 O is completely dissolved to obtain a copper precursor solution.

[0044] Preparation of catalyst by impregnation method: 3000 mg coconut shell activated carbon (S BET = 1108 m 2 / g) was spread flat in a mortar, and then the copper precursor solution was dripped into the activated carbon drop by drop and evenly. After the addition was completed, it was quickly ground in a clockwise direction until the catalyst surface was smooth. Then it was transferred to a watch glass and placed in a 90°C forced air drying oven to dry for 12 hours. After drying, it was sealed and stored. The mass of copper in the catalyst: activated carbon is 20:80.

[0045] The catalyst was named 20 wt.%Cu / AC-IWI.

[0046] Example 2 Catalyst Preparation

[0047] Preparation of catalyst by segmented continuous flow method: Weigh 3473 mg of cupric chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 ·2H 2 O was completely dissolved to obtain a copper precursor solution; 3000 mg coconut shell activated carbon (S BET = 1108 m 2 / g) was added into a container, and 90 mL of anhydrous ethanol was added for ultrasonic dispersion to obtain an activated carbon slurry; the inlet pipe of the peristaltic pump was introduced into the beakers containing the activated carbon slurry and the copper precursor solution, respectively, and the flow rate of the activated carbon slurry was set to 2 mL / min, and the flow rate of the copper precursor solution was set to 1 mL / min. The peristaltic pump switch was started at the same time, and the activated carbon slurry and the copper precursor solution were mixed at the first polypropylene tee; after flowing through a section of polytetrafluoroethylene pipe, it was mixed with N with a flow rate of 7 mL / min. 2 The gases were mixed at the second polypropylene tee to form a stable gas-liquid segmented flow. After waiting for 30 minutes, a solid-liquid mixture of the copper-based catalyst was obtained. After heating in a water bath at 60°C to evaporate the ethanol, the beaker was placed in a 90°C forced air drying oven for 12 hours and then sealed and stored. The mass of copper:activated carbon in the catalyst was 20:80, and each segmented continuous flow device could produce 311 g / d of copper-based catalyst.

[0048] The catalyst was named 20 wt.%Cu / AC-SMF 7 .

[0049] Example 3 Catalyst Preparation

[0050] Preparation of catalyst by segmented continuous flow method: Weigh 3473 mg of cupric chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 ·2H 2 O was completely dissolved to obtain a copper precursor solution; 3000 mg coconut shell activated carbon (S BET = 1108 m 2 / g) was added into a container, and 90 mL of anhydrous ethanol was added for ultrasonic dispersion to obtain an activated carbon slurry; the inlet pipe of the peristaltic pump was introduced into the beakers containing the activated carbon slurry and the copper precursor solution, respectively, and the flow rate of the activated carbon slurry was set to 2 mL / min, and the flow rate of the copper precursor solution was set to 1 mL / min. The peristaltic pump switch was started at the same time, and the activated carbon slurry and the copper precursor solution were mixed at the first polypropylene tee; after flowing through a section of polytetrafluoroethylene pipe, it was mixed with N at a flow rate of 13 mL / min. 2 The gases were mixed at the second polypropylene tee to form a stable gas-liquid segmented flow. After waiting for 30 minutes, a solid-liquid mixture of the copper-based catalyst was obtained. After heating in a water bath at 60°C to evaporate the ethanol, the beaker was placed in a 90°C forced air drying oven for 12 hours and then sealed and stored. The mass of copper:activated carbon in the catalyst was 20:80, and each segmented continuous flow device could produce 311 g / d of copper-based catalyst.

[0051] The catalyst was named 20 wt.%Cu / AC-SMF13 .

[0052] Example 4 Catalyst Preparation

[0053] Preparation of catalyst by segmented continuous flow method: Weigh 955 mg of cupric chloride dihydrate (CuCl 2 ·2H 2 O) solid was dissolved in 45 mL of anhydrous ethanol and stirred with a magnetic stirrer to make CuCl 2 ·2H 2 O was completely dissolved to obtain a copper precursor solution; 3000 mg coconut shell activated carbon (S BET = 1108 m 2 / g) was added into a container, and 90 mL of anhydrous ethanol was added for ultrasonic dispersion to obtain an activated carbon slurry; the inlet pipe of the peristaltic pump was introduced into the beakers containing the activated carbon slurry and the copper precursor solution, respectively, and the flow rate of the activated carbon slurry was set to 2 mL / min, and the flow rate of the copper precursor solution was set to 1 mL / min. The peristaltic pump switch was started at the same time, and the activated carbon slurry and the copper precursor solution were mixed at the first polypropylene tee; after flowing through a section of polytetrafluoroethylene pipe, it was mixed with N at a flow rate of 13 mL / min. 2 The gases were mixed at the second polypropylene tee to form a stable gas-liquid segmented flow. After waiting for 30 minutes, a solid-liquid mixture of the copper-based catalyst was obtained. After heating in a water bath at 60°C to evaporate the ethanol, the beaker was placed in a 90°C forced air drying oven for 12 hours and then sealed and stored. The mass ratio of copper to activated carbon in the catalyst was 9:91. Each segmented continuous flow device could produce 190 g / d of copper-based catalyst.

[0054] The catalyst is named 9 wt.%Cu / AC-SMF 13 .

[0055] The evaluation process and conditions of all catalysts in Example 5 are as follows:

[0056] (1) Catalyst loading: Place a layer of quartz wool with a thickness of 10 mm in the middle of a quartz reaction tube with a diameter of 10 mm, and add a certain amount of catalyst (GHSV (C 2 H 2 ) = 170 h -1 ) and ensure that the catalyst is flat, and then pad it with a layer of 10 mm thick quartz wool;

[0057] (2) Before the reaction: 2The entire pipeline was purged at a flow rate of 20 mL / min for 60 min to remove air and moisture in the reaction system. At the same time, the temperature was raised to 150 °C at 5 °C / min and maintained for 30 min, and then the temperature was further raised to 180 °C at 5 °C / min. Then, HCl gas was introduced at a flow rate of 20 mL / min and maintained for 30 min, and then V C2H2 =16mL / min, V HCl =16.8 mL / min flow rate of the reaction gas and maintain for 10 min to ensure that the catalyst is in the gas atmosphere of acetylene and hydrogen chloride, and then V C2H2 / V HCl =1:1.05 ratio to reduce the reaction gas flow rate, at V C2H2 =4 mL / min, V HCl =4.2 mL / min reaction flow rate, maintained for 10 min, and then began detection;

[0058] (3) After the reaction: The gaseous product first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then was analyzed online by gas chromatography GC-9790Ⅱ to evaluate the acetylene conversion rate and selectivity to VCM.

[0059] The catalyst test results are shown in Table 1.

[0060] Table 1 Acetylene hydrochlorination reaction activity test

[0061]

[0062] As can be seen from Table 1, the catalyst 20 wt.% Cu / AC-SMF prepared by the segmented continuous flow method in Example 3 13 , at a reaction temperature of 180°C, GHSV (C 2 H 2 )=170 h -1 Under the optimal conditions, the acetylene conversion rate reached 76.2%, and the VCM selectivity was higher than 99.9%, which was the best activity. Compared with the acetylene conversion rate (64.0%) obtained by 20 wt.% Cu / AC-IWI prepared by impregnation method, it was increased by 12.2% (such as Figure 2-3 At the same time, Figure 4 It can be seen that Examples 3-4 prepared copper-based catalysts with loading amounts of 20% and 9%, indicating that the segmented continuous flow method can be used to prepare copper-based catalysts with different loading amounts, and the catalyst with a loading amount of 20% prepared in Example 3 has the best activity.

[0063] The particle size distribution of copper species in the catalyst is shown in Table 2.

[0064] Table 2 Particle size distribution of copper species in the catalyst

[0065]

[0066] Combined with Table 2, it can be seen that as the gas flow rate increases, the liquid segment volume is smaller and the distribution is wider, and the copper species particles in the copper-based catalyst are smaller. When the activated carbon slurry flow rate is 2 mL / min, the copper precursor solution flow rate is 1 mL / min, and the gas flow rate is 13 mL / min, the catalyst 20 wt.%Cu / AC-SMF prepared in Example 3 has a 13 The copper species particles are evenly distributed, with the smallest particle size (3.90 ± 1.58 nm) and the best catalytic activity. Compared with the catalyst 20wt.%Cu / AC-IWI prepared by impregnation method (13.53 ± 4.70 nm), the particle size is reduced by about 9.63 nm (e.g. Figure 4-7 This shows that the method of the present invention has significant practical value.

[0067] The present invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent replacement are within the protection scope required by the present invention.

Claims

1. A method for preparing a supported copper-based catalyst using a segmented continuous flow technology, characterized in that: The following steps are involved: (1) Preparation of copper precursor solution: Weigh 3473 mg of copper chloride dihydrate (CuCl2·2H2O) solid and dissolve it in 45 mL of anhydrous ethanol. Use a magnetic stirrer to completely dissolve the CuCl2·2H2O to obtain a copper precursor solution. (2) Weighing 3000 mg of activated carbon into a container, adding an appropriate amount of anhydrous ethanol for ultrasonic dispersion to obtain an activated carbon slurry; the volume ratio of anhydrous ethanol used to prepare the activated carbon slurry and the copper precursor solution in steps (1) and (2) is 2:1, and the activated carbon is coconut shell activated carbon; (3) Preparation of copper-based catalyst using a segmented continuous flow device: The segmented continuous flow device is composed of a magnetic stirrer (2), a nitrogen bottle (4), a peristaltic pump (5), a polypropylene tee (6), a nitrogen flow meter (7), a polytetrafluoroethylene pipeline (8) and a collection device (9); The inlet end pipeline of the peristaltic pump (5) is respectively introduced into the beaker containing the activated carbon slurry (1) and the copper precursor solution (3), and the liquid is sucked into the pipeline through the peristaltic pump (5) and mixed at the first polypropylene tee (6); after flowing through a section of polytetrafluoroethylene pipeline, it merges with the gas flowing through the nitrogen flowmeter (7) at the second polypropylene tee to form a stable gas-liquid diversion section; the lower interface of the second polypropylene tee is connected to a section of polytetrafluoroethylene pipeline (8), and after waiting for a period of time, the mixed liquid is collected by a collecting device (9); the flow rate ratio of the activated carbon slurry, the copper precursor solution and the nitrogen in the preparation process of the segmented continuous flow technology is 2:1:13; (4) placing the beaker containing the solid-liquid mixture in a water bath and heating it at 60° C. to volatilize the anhydrous ethanol, and finally drying the obtained solid in a forced air drying oven for 12-24 h. The mass ratio of copper to activated carbon in the catalyst is 20:80; (5) The prepared copper-based catalyst is used in the reaction of acetylene hydrochloride to produce vinyl chloride.

2. The method for preparing a supported copper-based catalyst using a segmented continuous flow technique according to claim 1, characterized in that: The preparation method of the copper-based catalyst is as follows: 3473 mg of copper chloride dihydrate CuCl2·2H2O solid is weighed and dissolved in 45 mL of anhydrous ethanol, and the CuCl2·2H2O is completely dissolved with a magnetic stirrer to obtain a copper precursor solution; 3000 mg of activated carbon is weighed and added to a container, and 90 mL of anhydrous ethanol is added for ultrasonic dispersion to obtain an activated carbon slurry; the inlet end pipeline of the peristaltic pump is respectively introduced into the beaker containing the activated carbon slurry and the copper precursor solution, and the flow rate of the activated carbon slurry is set to 2 mL / min, and the flow rate of the copper precursor solution is set to 1 mL / min, and the peristaltic pump switch is started at the same time, and the activated carbon slurry and the copper precursor solution are mixed at the first polypropylene tee; After flowing through a section of polytetrafluoroethylene pipe, it was mixed with N2 gas at a flow rate of 13 mL / min at the second polypropylene tee to form a stable gas-liquid segmented flow. After waiting for 30 minutes, a solid-liquid mixture of the copper-based catalyst was obtained; after ethanol was evaporated by heating in a water bath, the beaker was placed in a 90 °C forced air drying oven and dried for 12 hours. After drying, it was sealed and stored; the mass ratio of copper to activated carbon in the catalyst was 20:80, and the catalyst was named 20 wt.%Cu / AC-SMF 13 .

3. The method for preparing a supported copper-based catalyst using a segmented continuous flow technique according to claim 1, characterized in that: The gas in step (3) is N2, and the solid-liquid mixture separation method in step (4) is water bath heating at a heating temperature of 60°C.

4. The method for preparing a supported copper-based catalyst using a segmented continuous flow technique according to claim 1, characterized in that: The container and collecting device is a beaker, and the polytetrafluoroethylene tubing connected to the lower interface of the second polypropylene tee is circularly wound.

5. The method for preparing a supported copper-based catalyst using a segmented continuous flow technique according to claim 1, characterized in that: In step (5), the acetylene hydrochloride is used to produce vinyl chloride, and the specific steps are as follows: (1) Catalyst loading: Place a layer of quartz wool with a thickness of 10 mm in the middle of a quartz reaction tube with a diameter of 10 mm, add a certain amount of catalyst into the reaction tube and ensure that the catalyst is flat, and then place another layer of quartz wool with a thickness of 10 mm; (2) Before the reaction: N2 was purged throughout the pipeline at a flow rate of 20 mL / min for 60 min to remove air and moisture in the reaction system. At the same time, the temperature was raised to 150 °C at a flow rate of 5 °C / min and maintained for 30 min, and then the temperature was further raised to 180 °C at a flow rate of 5 °C / min. Then, HCl gas was introduced at a flow rate of 20 mL / min and maintained for 30 min, and then V C2H2 =16 mL / min, V HCl =16.8 mL / min flow rate of the reaction gas and maintain for 10 min to ensure that the catalyst is in the gas atmosphere of acetylene and hydrogen chloride, and then V C2H2 / V HCl =1:1.05 ratio to reduce the reaction gas flow rate, at V C2H2 =4 mL / min, V HCl =4.2mL / min reaction flow rate, maintained for 20 min, and then began detection; (3) After the reaction: The gaseous product first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then was analyzed online by gas chromatography GC-9790Ⅱ to evaluate the acetylene conversion rate and VCM selectivity.

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