Alumina-loaded ruthenium-erbium-cerium trimetal catalyst for acetylene hydrochlorination reaction as well as preparation and application of alumina-loaded ruthenium-erbium-cerium trimetal catalyst

Abstract

The invention discloses an aluminum oxide loaded ruthenium-erbium-cerium tri-metal catalyst for acetylene hydrochlorination reaction as well as preparation and application of the aluminum oxide loaded ruthenium-erbium-cerium tri-metal catalyst. The catalyst comprises a carrier and a metal active component loaded on the carrier, wherein the carrier is porous alumina; the alumina-loaded ruthenium-erbium-cerium tri-metal catalyst is prepared by the following steps: uniformly adsorbing a salt solution containing ruthenium salt, erbium salt and cerium salt onto a carrier through wet impregnation, and then drying and calcining in an air atmosphere to obtain the alumina-loaded ruthenium-erbium-cerium tri-metal catalyst. The invention provides application of the catalyst in acetylene hydrochlorination reaction. The aluminum oxide loaded ruthenium-erbium-cerium trimetal catalyst is applied to acetylene hydrochlorination reaction, the acetylene conversion rate is high, the vinyl chloride selectivity is high, and the catalyst stability is good.

Description

(I) Technical field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to an alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination reaction, a preparation method thereof, and application thereof in acetylene hydrochlorination reaction. (II) Background technology

[0002] Polyvinyl chloride (PVC for short) is one of the world's top five engineering plastics and is widely used in the chemical industry. Vinyl chloride (VCM for short) is a monomer for synthesizing PVC. The current annual demand for PVC is 400 million tons, which makes VCM a very important chemical raw material. About 90% of VCM is used to produce PVC. There are three main chemical synthesis processes for vinyl chloride, namely, the C2H2 method, the C2H4 method, and the C2H6 method. The calcium carbide acetylene method will be the main process for vinyl chloride production in my country, that is, mercuric chloride catalyzes the reaction of acetylene and hydrogen chloride to produce vinyl chloride. The activity and selectivity of this catalyst are relatively high, but the thermal stability is poor. During use, it will cause the loss of mercury in the catalyst, thereby affecting the activity. What is more serious is that the highly toxic mercuric chloride causes serious pollution to the environment. At present, many scholars are actively exploring how to replace mercury catalysts in the acetylene hydrochlorination reaction and seeking a green and efficient technical route. People have gradually focused their research on mercury-free chlorides with metal chlorides as active components. Among them, precious metal chlorides show the best catalytic activity. For example, gold, palladium, ruthenium, copper and other metals as active components have been reported to have higher catalytic activity than mercury.

[0003] Among them, Au-based mercury-free catalysts have better activity and stability, and are currently the most promising non-mercury catalysts for industrial applications. However, gold-based catalysts are expensive, and there are many problems that need to be solved in industrialization. The price of ruthenium is much lower than that of gold, and its excellent catalytic performance has received more attention and research. However, low-content ruthenium catalysts have low activity, unstable ruthenium trichloride aqueous solution, easy agglomeration during the reaction, weak interaction with the carrier, and easy generation of coke deposition. In response to the problems of the above-mentioned ruthenium catalysts, many studies have been conducted from the aspects of changing the valence state of ruthenium and compounds, adding additives, ligand complexation, ionic liquids, preparation methods, and carrier modification.

[0004] Therefore, designing a highly active and stable ruthenium-based catalyst for acetylene hydrochlorination has great application prospects. (III) Summary of the invention

[0005] The present invention aims to provide an alumina-supported ruthenium-erbium-cerium trimetallic catalyst and its preparation and application in acetylene hydrochlorination reaction, so as to solve the problem of low activity and poor stability of ruthenium-based catalyst in the reaction of acetylene hydrochlorination to synthesize vinyl chloride.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0007] In the first aspect, the present invention provides an alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination reaction, wherein the catalyst comprises a carrier and a metal active component supported on the carrier, wherein the carrier is porous alumina; the alumina-supported ruthenium-erbium-cerium trimetallic catalyst is prepared by the following method: a salt solution containing a ruthenium salt, an erbium salt and a cerium salt is uniformly adsorbed onto the carrier by wet impregnation, and then dried and calcined in an air atmosphere to obtain the alumina-supported ruthenium-erbium-cerium trimetallic catalyst.

[0008] Preferably, the average particle size of the porous alumina is between 3 and 4 mm, and the specific surface area is between 1000 and 1200 m 2 / g.

[0009] Preferably, the feed ratio of the ruthenium salt, erbium salt and cerium salt is 10%:25-35%:55-65% based on the mass ratio of the metal elements ruthenium, erbium and cerium contained therein, and more preferably 10%:29-31%:59-61%.

[0010] Preferably, in the alumina-supported ruthenium-erbium-cerium trimetallic catalyst, the loading amount of ruthenium (relative to the carrier) is 0.5-0.6 wt %.

[0011] Preferably, the wet impregnation is to immerse the support in a salt solution containing ruthenium salt, erbium salt and cerium salt, and immerse it in a fume hood at room temperature for 6-8 hours.

[0012] Preferably, the drying condition is: drying in an oven at 100° C.-110° C. for 20-24 hours.

[0013] Preferably, the calcination temperature is 1000-1100° C. and the calcination time is 5-6 hours.

[0014] In a second aspect, the present invention provides a method for preparing the alumina-supported ruthenium-erbium-cerium trimetallic catalyst according to the first aspect, comprising the following steps:

[0015] Step 1: Mix ruthenium salt, erbium salt and cerium salt in proportion and add them to a solvent to dissolve, so as to prepare a salt solution;

[0016] Step 2: Immerse the carrier in a salt solution, dry it after sufficient immersion, and calcine it in an air atmosphere to obtain an alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination reaction.

[0017] Preferably, the ruthenium salt in step 1 is anhydrous ruthenium chloride, the erbium salt is Er(NO3)3·5H2O, the cerium salt is Ce(NO3)2·6H2O, and the solvent is deionized water.

[0018] Preferably, the immersion condition in step 2 is to immerse in a fume hood at room temperature for 6-8 hours.

[0019] Preferably, the drying condition in step 2 is: drying in an oven at 100° C.-110° C. for 20-24 hours.

[0020] Preferably, the calcination conditions in step 2 are: calcining in an air atmosphere at 1000° C.-1100° C. using a muffle furnace at a heating rate of 5-10° C. / min for 5-6 hours.

[0021] In a third aspect, the present invention provides the use of the alumina-supported ruthenium-erbium-cerium trimetallic catalyst described in the first aspect in the acetylene hydrochlorination reaction.

[0022] The application is specifically as follows: in a fixed bed reactor, the alumina-supported ruthenium-erbium-cerium trimetallic catalyst is loaded, raw gas HCl and C2H2 are introduced, the reaction temperature is controlled to be 120-200°C, and the reaction pressure is controlled to be 0.01-2MPa to react and generate vinyl chloride.

[0023] Furthermore, the molar ratio of the raw gas is n(HCl):n(C2H2)=1:1-1.2:1, and the volumetric space velocity of acetylene is 5-500h -1 .

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention uses porous alumina instead of commonly used activated carbon as a carrier, and the prepared catalyst has high catalytic activity and mechanical strength, and good stability; the use of a trimetallic catalyst makes the catalyst have better catalytic activity, thereby solving the problem of low activity and poor stability of ruthenium catalysts.

[0026] (2) The catalyst preparation method of the present invention uses readily available reagents, has low cost, simple process, and has good application prospects.

[0027] (3) The alumina-supported ruthenium-erbium-cerium trimetallic catalyst of the present invention is applied to the acetylene hydrochlorination reaction, with high acetylene conversion rate, high vinyl chloride selectivity and good catalyst stability. (IV) Specific implementation methods

[0028] The present invention is described below with specific examples. It is necessary to point out that the examples are only used to further illustrate the present invention, but cannot be understood as limiting the scope of protection of the present invention, and the present invention is not limited thereto in any way. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.

[0029] Example 1

[0030] 2.7 g Ce(NO3)3·6H2O was dissolved in 20 mL deionized water in a beaker. Then, 0.3 g RuCl3 and 1.2 g Er(NO3)3·5H2O were added to the beaker and mixed with the cerium nitrate solution. The mixture was stirred at room temperature at 100 r / min for 30 min. 25 g alumina balls with an average diameter of 4 mm (specific surface area 1117.2549 m 2 / g, total pore volume 0.607815cc / g, the same below) was immersed in the prepared metal salt solution and placed in a fume hood for immersion for 8 hours. After immersion, the catalyst was placed in an oven at 100°C for 24 hours and then calcined in an air atmosphere at 1000°C for 6 hours using a muffle furnace at a heating rate of 10°C / min to obtain a catalyst with a metal loading ratio of Ru:Er:Ce of 10wt%:30wt%:60wt%, wherein the Ru loading amount was 0.5wt%, recorded as catalyst 1.

[0031] Application of Catalyst 1 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 99.2% and the vinyl chloride selectivity was 98.8%; after 1000 hours of reaction, the acetylene conversion rate was 84.13% and the vinyl chloride selectivity was 97.0%.

[0032] Example 2

[0033] 2.5 g of Ce(NO3)3·6H2O was dissolved in 20 mL of deionized water in a beaker. Then, 0.3 g of RuCl3 and 1.33 g of Er(NO3)3·5H2O auxiliary salt were added to the beaker and mixed with the cerium nitrate solution, and magnetic stirring was performed at 100 r / min for 30 min at room temperature. 25 g of alumina balls with an average diameter of 4 mm were immersed in the prepared metal salt solution and placed in a fume hood for 8 h. After immersion, the catalyst was placed in an oven at 100°C and dried for 24 h, and then calcined in a muffle furnace at 1000°C in an air atmosphere at a heating rate of 10°C / min for 6 h to obtain a catalyst with a metal loading ratio of Ru:Er:Ce of 10 wt%:35 wt%:55 wt%, wherein the Ru loading amount was 0.5 wt%, recorded as catalyst 2.

[0034] Application of Catalyst 2 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2)=1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 97.4% and the vinyl chloride selectivity was 97.6%; after 1000 hours of reaction, the acetylene conversion rate was 70.6% and the vinyl chloride selectivity was 93.4%.

[0035] Example 3

[0036] 2.95 g of Ce(NO3)3·6H2O was dissolved in 20 mL of deionized water in a beaker. Then, 0.3 g of RuCl3 and 0.96 g of Er(NO3)3·5H2O auxiliary salt were added to the beaker and mixed with the cerium nitrate solution, and magnetic stirring was carried out at room temperature at 100 r / min for 30 min. 25 g of alumina balls with an average diameter of 4 mm were immersed in the prepared metal salt solution and placed in a fume hood for 8 h. After immersion, the catalyst was placed in an oven at 100°C and dried for 24 h. Then, it was calcined in a muffle furnace at 1000°C in an air atmosphere at a heating rate of 10°C / min for 6 h to obtain a catalyst with a metal loading ratio of Ru:Er:Ce of 10 wt%:25 wt%:65 wt%, wherein the Ru loading amount was 0.5 wt%, recorded as catalyst 3.

[0037] Application of Catalyst 3 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 96.2% and the vinyl chloride selectivity was 97.8%; after 1000 hours of reaction, the acetylene conversion rate was 72.88% and the vinyl chloride selectivity was 94.5%.

[0038] Comparative Example 1

[0039] Comparative Example 1 is compared with Example 1 to illustrate that the trimetallic catalyst system has a key influence on the catalytic activity of the catalyst.

[0040] 2.7 g Ce(NO3)3·6H2O was dissolved in 20 mL deionized water in a beaker. Then, 0.3 g RuCl3 was added to the cerium nitrate solution and mixed. The mixture was stirred at 100 r / min for 30 min at room temperature. 25 g alumina balls with an average diameter of 4 mm were immersed in the prepared metal salt solution and placed in a fume hood for 8 h. After impregnation, the catalyst was placed in an oven at 100 ° C and dried for 24 h. Then, the catalyst was calcined in a muffle furnace at 1000 ° C in an air atmosphere at a heating rate of 10 ° C / min for 6 h to obtain a catalyst with a Ru loading of 0.5 wt%, which was recorded as catalyst 4.

[0041] Application of Catalyst 4 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 95.8% and the vinyl chloride selectivity was 96.9%; after 1000 hours of reaction, the acetylene conversion rate was 66.4% and the vinyl chloride selectivity was 93.4%.

[0042] Comparative Example 2

[0043] Comparative Example 2 is compared with Example 1 to illustrate that the trimetallic catalyst system has a critical influence on the catalytic activity of the catalyst.

[0044] In a beaker, 0.3 g of RuCl3 and 1.2 g of Er(NO3)3·5H2O were dissolved in 20 mL of deionized water and mixed. Then, the mixture was magnetically stirred at 100 r / min at room temperature for 30 min. 25 g of alumina balls with an average diameter of 4 mm were immersed in the prepared metal salt solution and placed in a fume hood for immersion for 8 h. After immersion, the catalyst was placed in an oven at 100°C and dried for 24 h. Then, it was calcined in an air atmosphere at 1000°C using a muffle furnace at a heating rate of 10°C / min for 6 h to obtain a catalyst with a Ru loading of 0.5 wt%, which was recorded as catalyst 5.

[0045] Application of Catalyst 5 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 92.9% and the vinyl chloride selectivity was 96.3%; after 1000 hours of reaction, the acetylene conversion rate was 56.1% and the vinyl chloride selectivity was 92.2%.

[0046] Comparative Example 3

[0047] Dissolve 0.3 g of RuCl3 in 20 mL of deionized water in a beaker and stir magnetically at 100 r / min at room temperature for 30 min. Immerse 25 g of alumina balls with an average diameter of 4 mm in the prepared metal salt solution and place in a fume hood for immersion for 8 h. After immersion, place the catalyst in an oven at 100°C and dry it for 24 h. Then, use a muffle furnace in an air atmosphere at 1000°C and calcine for 6 h at a heating rate of 10°C / min to obtain a catalyst with a Ru loading of 0.5 wt%, recorded as Catalyst 6.

[0048] Application of Catalyst 6 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 91.4% and the vinyl chloride selectivity was 95.7%; after 1000 hours of reaction, the acetylene conversion rate was 56.9% and the vinyl chloride selectivity was 93.1%.

[0049] Comparative Example 4

[0050] Comparative Example 4 is compared with Comparative Example 3 to illustrate that using alumina as a carrier can improve the stability of the catalyst.

[0051] Select 25g of columnar medium activated carbon carrier, wash, remove ash and dry for standby use. Dissolve 0.3g of RuCl3 in 20mL of deionized water in a beaker, stir magnetically at 100r / min for 30min at room temperature, immerse 25g of columnar medium activated carbon with an average particle size of 4mm in the prepared metal salt solution, place it in a fume hood and immerse it for 8h, and after immersion, put the catalyst in an oven at 100℃ and dry it for 24h, then use a muffle furnace in an air atmosphere at 1000℃ and calcine it at a heating rate of 10℃ / min for 6h to obtain a catalyst with a Ru loading of 0.5wt%, which is recorded as catalyst 7.

[0052] Application of Catalyst 7 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 90.6% and the vinyl chloride selectivity was 96.3%; after 1000 hours of reaction, the acetylene conversion rate was 35.9% and the vinyl chloride selectivity was 92.2%.

[0053] Comparative Example 5

[0054] Comparative Example 5 is compared with Example 1 to illustrate that using alumina as a carrier can improve the stability of the catalyst.

[0055] Select 25g of columnar medium activated carbon carrier, wash, deash and dry for standby use. Dissolve 2.7gCe(NO3)3·6H2O in 20mL deionized water in a beaker. Then, mix 0.3g RuCl3 and 1.2gEr(NO3)3·5H2O auxiliary salt with the cerium nitrate solution in the beaker, stir magnetically at 100r / min for 30min at room temperature, immerse 25g of columnar medium activated carbon with an average diameter of 4mm in the prepared metal salt solution, place it in a fume hood and immerse it for 8h. After immersion, put the catalyst in an oven at 100℃ and dry it for 24h, then use a muffle furnace in an air atmosphere at 1000℃ and calcine it at a heating rate of 10℃ / min for 6h to obtain a catalyst with a metal loading ratio of Ru:Er:Ce of 10wt%:30wt%:60wt%, wherein the Ru loading amount is 0.5wt%, recorded as catalyst 8.

[0056] Application of Catalyst 8 in Acetylene Hydrochlorination Reaction: Acetylene hydrochlorination reaction was evaluated in a fixed bed reactor under the following reaction conditions: temperature 140°C, reaction pressure 0.01 MPa, n(HCl):n(C2H 2) =1.1:1, acetylene space velocity is 15h -1 At the initial stage of the reaction, the acetylene conversion rate was 99.0% and the vinyl chloride selectivity was 98.1%; after 1000 hours of reaction, the acetylene conversion rate was 68.92% and the vinyl chloride selectivity was 95.5%.

Claims

1. An alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination, characterized in that: The catalyst includes a carrier and a metal active component supported on the carrier, wherein the carrier is porous alumina; the alumina-supported ruthenium-erbium-cerium trimetallic catalyst is prepared by the following method: a salt solution containing ruthenium salt, erbium salt and cerium salt is uniformly adsorbed onto the carrier by wet impregnation, and then dried and calcined in an air atmosphere to obtain the alumina-supported ruthenium-erbium-cerium trimetallic catalyst.

2. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: The average particle size of the porous alumina is between 3-4 mm and the specific surface area is between 1000-1200 m 2 / g.

3. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: The feed ratio of the ruthenium salt, the erbium salt and the cerium salt is 10%:25-35%:55-65% based on the mass ratio of the metal elements ruthenium, erbium and cerium contained therein, and more preferably 10%:29-31%:59-61%.

4. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: In the alumina-supported ruthenium-erbium-cerium trimetallic catalyst, the loading amount of ruthenium relative to the carrier is 0.5-0.6 wt %.

5. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: The wet impregnation is to immerse the carrier in a salt solution containing ruthenium salt, erbium salt and cerium salt, and immerse it in a fume hood at room temperature for 6-8 hours.

6. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: Drying conditions: drying in an oven at 100°C-110°C for 20-24 hours.

7. The alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination as claimed in claim 1, characterized in that: The calcination temperature is 1000-1100°C and the calcination time is 5-6h.

8. A method for preparing the alumina-supported ruthenium-erbium-cerium trimetallic catalyst according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Step 1: Mix ruthenium salt, erbium salt and cerium salt in proportion and add them to a solvent to dissolve, so as to prepare a salt solution; Step 2: Immerse the carrier in a salt solution, dry it after sufficient immersion, and calcine it in an air atmosphere to obtain an alumina-supported ruthenium-erbium-cerium trimetallic catalyst for acetylene hydrochlorination reaction.

9. The method according to claim 8, characterized in that: The ruthenium salt described in step 1 is anhydrous ruthenium chloride, the erbium salt is Er(NO3)3·5H2O, the cerium salt is Ce(NO3)2·6H2O, and the solvent is deionized water.

10. Use of the alumina-supported ruthenium-erbium-cerium trimetallic catalyst as claimed in any one of claims 1 to 8 in acetylene hydrochlorination reaction.