Method for applying nitrogen-oxygen ligand modified low-content ruthenium-based catalyst to acetylene hydrochlorination reaction

Abstract

According to the method, 2-picolinic acid hydrochloride is used as a ligand, commercial activated carbon is used as a carrier, trace ruthenium is used as a main active component, water is used as a solvent, and the nitrogen-oxygen ligand modified low-content ruthenium-based catalyst is prepared through improved synthesis steps. According to the low-content ruthenium-based catalyst with the commercial activated carbon as the carrier, the ruthenium content is reduced, and meanwhile the performance of the catalyst is remarkably improved. The catalyst has relatively high activity and vinyl chloride selectivity in a reaction for preparing vinyl chloride through acetylene hydrochlorination on a fixed bed, is relatively low in cost and has relatively high industrial application value. Under the conditions that the reaction gas space velocity is 170h <-1 >, V (C2H2) / V (HCl) is 1: 1.05 and the reaction temperature is 180 DEG C, the acetylene conversion rate can reach 84.3%, the vinyl chloride selectivity is greater than 99%, and the activity is basically kept unchanged within 10h.

Description

Technical Field

[0001] The invention belongs to the field of catalyst preparation technology and application, and specifically relates to the preparation of a nitrogen oxide ligand-modified low-content ruthenium-based catalyst and its application in acetylene hydrochlorination reaction. Background Art

[0002] As the world's second largest general-purpose resin, polyvinyl chloride is obtained by polymerizing vinyl chloride monomer. Due to its advantages such as wide raw material sources, low cost, and strong performance adjustability, it is widely used in many fields such as construction, industry, agriculture, and daily necessities. The main method for industrial preparation of vinyl chloride in my country is the acetylene method. Under the action of mercuric chloride catalyst, acetylene and hydrogen chloride are added to directly synthesize vinyl chloride. This method has simple process and equipment, low investment, and high yield, but it consumes a lot of energy and has high raw material costs. The used mercuric chloride catalyst seriously harms the environment and human health. At present, my country is gradually restricting the use of HgCl2 catalysts. Therefore, the development of environmentally friendly, non-toxic, and industrially valuable mercury-free catalysts has become an urgent problem to be solved in the production of vinyl chloride by acetylene hydrochlorination.

[0003] Based on the findings of Hutching et al., there is an obvious positive correlation between the catalytic activity of metal cations and their standard electrode potential during the acetylene hydrochlorination reaction. Based on this finding, metals with high redox potentials such as Au, Pd, Pt, Ru, Cu and Bi have been widely studied. Among them, Au catalysts stand out among many metals with their excellent catalytic activity. However, with the rise in gold prices in recent years, Au catalysts have become increasingly difficult to apply to industrial production. The price of Ru is only one-fifth of the price of Au, and Ru has a greater advantage in the preparation cost of mercury-free catalysts, which has attracted widespread attention from researchers. According to the research of Zhu et al., in the process of acetylene hydrochlorination, RuCl3 has the lowest acetylene hydrochlorination reaction energy barrier compared with AuCl3 and HgCl2. At the same time, with the increasingly stringent environmental protection requirements, ruthenium-based catalysts, as a mercury-free catalyst, have broad application prospects.

[0004] Patent CN109331869A prepared a low-content and highly active ruthenium-based catalyst by introducing oxalic acid as a ligand to improve the catalytic activity. When the mass ratio of ruthenium to oxalic acid was 1:15, the catalyst showed the best activity, V(HCl) / V(C2H2)=1.15, T=170℃, GHSV(C2H2)=180h -1The performance test was carried out under the conditions of 200 ℃ and 800 ℃. The test results showed that the acetylene conversion rate of 0.25%Ru-15 / AC reached 80.9%, which was 22.1% higher than that of the unmodified catalyst 0.25%Ru / AC. The TEM results showed that oxalic acid can effectively inhibit the sintering of active species during the reaction, and the XPS results showed that oxalic acid modification can promote the formation of ruthenium oxide in ruthenium-based catalysts, and can effectively inhibit the reduction of ruthenium oxide to low-valent ruthenium during the acetylene hydrochlorination reaction. Although its catalyst activity is high, its loading is still high, which is not conducive to industrial production.

[0005] Although the above studies have screened a series of ligands to modify ruthenium-based catalysts, which inhibited the reduction of high-valent ruthenium species and improved the stability and catalytic activity of the catalysts, ruthenium is a precious metal and a higher loading amount will lead to higher catalyst costs. Therefore, how to reduce the ruthenium loading amount while improving the activity has become a top priority for the industrial application of ruthenium-based catalysts. Summary of the invention

[0006] The technical problem solved by the present invention is to propose a method for using a low-content ruthenium-based catalyst modified by nitrogen oxide ligands for acetylene hydrochlorination reaction. The innovation of this method is that a series of organic chloride salts are prepared by combining the ligand with hydrochloric acid, so that they have better stability and hydrogen chloride activation ability, and the high-valent ruthenium species in the ruthenium-based catalyst are stabilized by the synergistic effect of nitrogen oxides, thereby preparing a catalyst with low ruthenium content, high activity and good stability. The ruthenium loading is 0.1%, which is lower than the content reported in most prior arts. When the reaction gas space velocity is 170h -1 , V (C2H2) / V (HCl) =1:1.05, and the reaction temperature is 180℃, the acetylene conversion rate can reach 84.3%, the vinyl chloride selectivity is greater than 99%, and the activity remains basically unchanged after 10 hours, providing a unique and effective solution for the low-cost and high-efficiency production of vinyl chloride in industry.

[0007] In order to solve the technical problem of the present invention, the technical solution proposed is: using the catalyst for the fixed-bed acetylene hydrochlorination reaction to produce vinyl chloride, at an acetylene space velocity of 170 h -1 , V (C2H2) / V (HCl) =1:1.05, vinyl chloride is produced under the condition of reaction temperature of 180℃;

[0008] The method for preparing a low-content ruthenium-based catalyst for acetylene hydrochlorination reaction comprises the following steps:

[0009] (1) Prepare the precursor solution: first weigh 0.766g of ruthenium trichloride (RuCl3≥99%) solid and dissolve it in 10ml of distilled water, shake and sonicate, and then dilute to a 50ml brown round-bottom flask to obtain RuCl3 mother solution, Ru: 7.47mg / ml;

[0010] (2) Dissolve 15 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir at 350 rpm with a magnetic stirrer at room temperature, then add hydrochloric acid at a molar ratio of 1:1 to 2-picolinic acid, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0011] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90;

[0012] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0013] Preferably, in step (1), distilled water is used as a solvent, and an appropriate amount of ruthenium trichloride (RuCl3) solid is dissolved in distilled water at room temperature, and the mixture is shaken for 10 minutes using a mixer, and then ultrasonically treated for 30 minutes to prepare a mother solution of RuCl3 of 7.47 mg / ml, which is then sealed and stored at low temperature away from light.

[0014] Preferably, in step (2), the volume ratio of the activated carbon mass to the distilled water used in the ruthenium precursor solution is 1:2.

[0015] Preferably, the mass ratio of ruthenium to ligand in step (2) is 1:10.

[0016] Preferably, the molar ratio of the hydrochloric acid and the modifier in step (2) is 1:1.

[0017] Preferably, the activated carbon in step (3) is in the shape of a column, powder or flake, with a particle size of 200 mesh and a specific surface area of ​​1000-1200m 2 / g.

[0018] Preferably, the catalyst after grinding in step (3) should have a smooth surface and then be dried in a forced air drying oven at 90°C.

[0019] Preferably, the specific steps are as follows:

[0020] (1) Loading the catalyst: 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 the catalyst into the reaction tube and ensure that the catalyst is flat, and then pad it with another layer of quartz wool with a thickness of 10 mm.

[0021] (2) Before the reaction: The entire pipeline was purged with N2 at a flow rate of 20 mL / min for 60 min to remove air and moisture in the system. At the same time, the temperature was controlled to rise to 150°C at 5°C / min and maintained for 30 min, and then raised to 180°C at 5°C / min. Then, HCl was introduced at a flow rate of V = 20 mL / min and maintained for 30 min, followed by the introduction of the reaction gas at a flow rate of V(C2H2) = 16 mL / min, V(HCl) = 16.8 mL / min and maintained for 10 min to ensure that the catalyst was in the gas atmosphere of acetylene and hydrogen chloride, and then the reaction gas flow rate was reduced to a ratio of V(C2H2) / V(HCl) = 1:1.05. After maintaining the reaction flow rate for ten minutes, online detection was started.

[0022] (3) After the reaction: The gaseous product is first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then analyzed online by gas chromatography to evaluate the acetylene conversion rate and selectivity for vinyl chloride.

[0023] Beneficial effects:

[0024] The present invention provides a method for preparing a low-content ruthenium-based catalyst modified by nitrogen oxide ligands. Compared with other methods, the method greatly reduces the preparation cost, is simpler to operate and can be expanded. The technical scheme adopted by the present invention is: by using one or more of (Hpic[Cl]=2-picolinic acid hydrochloride, Py[Cl]=pyridine hydrochloride, Pz[Cl]=piperazine hydrochloride, Pip[Cl]=piperidine hydrochloride, MTBD[Cl]=7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene hydrochloride, BA=benzoic acid, Hpmc[Cl]=pyrimidine-2-carboxylic acid hydrochloride, Hpyza[Cl]=2-carboxylic acid pyrazine hydrochloride, Hpydc[Cl]=pyridine-2,6-dicarboxylic acid hydrochloride) as a ligand modifier to modify the ruthenium-based catalyst, water is selected as a solvent, and the content of Ru in the catalyst is greatly reduced, and a low-content ruthenium-based catalyst modified by nitrogen oxide ligands is prepared. The production cost is effectively saved; the catalyst prepared by the invention has excellent catalytic performance for acetylene hydrochlorination reaction and is suitable for industrial production.

[0025] (1) The catalyst uses a nitrogen-containing ligand as a modifier, ruthenium as the main active component, and water as a solvent. The catalyst's performance is improved by rationally adjusting the optimal ratio of the modified carbon support and the solvent: support / g: solution / ml=0.5 and improving the synthesis steps.

[0026] (2) Modifiers used in the present invention: 2-pyridinecarboxylic acid hydrochloride, pyridine hydrochloride, piperazine hydrochloride, piperidine hydrochloride, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene hydrochloride, benzoic acid, pyrimidine-2-carboxylic acid hydrochloride, 2-carboxylic acid pyrazine hydrochloride, pyridine-2,6-dicarboxylic acid hydrochloride or more are selected as ligand modifiers. Under the same conditions, the introduction of nitrogen (oxygen)-containing ligands forms a stable coordination bond with the active Ru species, thereby stabilizing the active ruthenium species, improving the catalytic activity, and reducing the deactivation rate. Through a large number of experiments, the modifier used in the present invention is preferably 2-pyridinecarboxylic acid hydrochloride. The ruthenium loading is lower than the content reported in most prior arts, which is only 0.1%. When the reaction gas C2H2 space velocity is 170h -1 , V (C2H2) / V (HCl) =1:1.05, and the reaction temperature is 180℃, the acetylene conversion rate can reach 84.3%, the vinyl chloride selectivity is greater than 99%, and the activity remains basically unchanged after 10 hours, providing a unique and effective solution for the low-cost and high-efficiency production of vinyl chloride in industry.

[0027] Compared with the prior art: first, the modifier selected in the present invention is non-toxic and harmless, and the price is low; second, the amount of the modifier used in the present invention is small, and the utilization rate is high, so the modification cost is lower than other technologies. In short, the method of the present invention significantly improves the catalytic activity and stability of the catalyst through the interaction between nitrogen (oxygen) and active ruthenium species. Compared with unmodified ruthenium-based catalysts, the synthesis method in this technology can show excellent catalytic activity and can be used as an industrial application.

[0028] (3) In step (2) of the present invention, 15 mg of 2-picolinic acid is dissolved in 3 ml of H2O for dispersion, and a magnetic stirrer is used at 350 rpm at room temperature. Then, hydrochloric acid is added, and the molar ratio of hydrochloric acid to modifier is 1:1. The mixture is stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride. Finally, 201 μl of RuCl3 mother liquor is added, and the beaker is covered with a sealing film and then covered with tin foil. The mixture is stirred at 350 rpm for 5 h at room temperature to obtain a mixed solution of ruthenium and ligand.

[0029] (4) The mixed solution in step (3) of the present invention is evenly dripped onto the surface of the activated carbon, and the catalyst is ground in a clockwise direction to be smooth within 10 minutes, and then placed in a 90°C forced air drying oven for drying. Grinding to be smooth in a short time can reduce the contact between the catalyst and air at room temperature and improve the loading rate and dispersion of the active components.

[0030] (5) 0.1%Ru1%Hpic[Cl] / AC catalyst, at an acetylene space velocity of 170h-1 At T = 180 ° C, the conversion rate of acetylene is 84.3%, the selectivity of vinyl chloride is 99%, and the activity remains basically unchanged within 10 hours.

[0031] (6) The 0.1wt%Ru1%MTBD[Cl] / AC catalyst of Example 5 was heated to 170h at an acetylene hourly velocity. -1 At T = 180 ° C, the conversion rate of acetylene was 86.1%, and the selectivity of vinyl chloride was 99%, but deactivation occurred within 10 hours. The 0.1%Ru1%Hpic[Cl] / AC catalyst of Example 1 was deactivated at an acetylene space velocity of 170 h -1 At T = 180 ° C, the conversion of acetylene was 84.3%, the selectivity of vinyl chloride was 99%, and the activity remained basically unchanged within 10 hours. Compared with the unmodified 0.1%Ru / AC catalyst, the conversion rate increased by 20.9%. Compared with the rapid deactivation of 0.1%Ru1%Py[Cl] / AC in Example 2, the high stability of the 0.1%Ru1%Hpic[Cl] / AC catalyst in Example 1 indicates that the introduction of carboxyl groups enhances the stability of the catalyst, and compared with the low activity of 0.1%Ru1%BA / AC in Example 6, the high activity of the 0.1%Ru1%Hpic / AC catalyst indicates that the interaction between Ru and pyridine nitrogen is the main active site.

[0032] (7) The effect of Hpic loading on the catalytic performance of Ru-Hpic / AC catalyst was further studied. It can be seen from Example 1 and Comparative Examples 1-1, 1-2, 1-3, and 1-4 that when the Hpic loading increases from 0.5% to 1%, the acetylene conversion rate of Ru-Hpic[Cl] / AC does not change significantly, but the deactivation rate of the catalyst gradually decreases with the increase of Hpic loading. When the Hpic loading further increases, the catalytic activity gradually decreases and the deactivation rate gradually increases. This may be due to the excessive introduction of Hpic shielding some active sites. Therefore, the optimal Hpic loading is determined to be 1%, that is, m Ru :m Hpic[Cl] =1:10, the catalyst of Example 1 is the best. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] Figure 1 The relationship between acetylene conversion rate and reaction time of ruthenium-based catalysts modified with different ligands.

[0035] Figure 2 The selectivity-reaction time relationship of ruthenium-based catalysts modified with different ligands. DETAILED DESCRIPTION

[0036] Example 1 Catalyst Preparation

[0037] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0038] (2) Dissolve 15 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0039] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0040] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0041] (5) The prepared ruthenium-based catalyst is used in the fixed-bed acetylene hydrochlorination reaction to produce vinyl chloride.

[0042] The catalyst was named 0.1%Ru1%Hpic[Cl] / AC*.

[0043] The steps of using the low-content ruthenium-based catalyst modified with nitrogen oxide ligands for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are as follows:

[0044] 1. Loading the catalyst: 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 1.00 g 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;

[0045] 2. Before reaction: The whole pipeline was heated at 20 mL min −1The system was purged with N2 flow rate for 60 min to remove air and moisture in the system. At the same time, the temperature was controlled to be increased to 150°C at 5°C / min and maintained for 30 min, and then increased to 180°C at 5°C / min; then, hydrogen chloride was introduced at a flow rate of V=20mL / min and maintained for 30 min, and then the reaction gas was introduced at a flow rate of V(C2H2) =16 mL / min, V(HCl) =16.8mL / min and maintained for 10 min to ensure that the catalyst was in the gas atmosphere of acetylene and hydrogen chloride, and then the reaction gas flow rate was reduced to V(C2H2)=4ml / min, V(C2H2) / V(HCl)=1:1.05. After maintaining at the reaction flow rate for ten minutes, the detection was started;

[0046] 3. After the reaction: The gas phase product is first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then analyzed online by gas chromatography to evaluate the acetylene conversion rate and selectivity to VCM.

[0047] Comparative Example 1-1

[0048] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0049] (2) Dissolve 7.5 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0050] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:0.5:99.40.

[0051] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0052] The catalyst was named 0.1%Ru0.5%Hpic[Cl] / AC*.

[0053] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0054] Comparative Example 1-2

[0055] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0056] (2) Dissolve 30 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0057] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution obtained in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:2:97.90.

[0058] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0059] The catalyst was named 0.1%Ru2%Hpic[Cl] / AC*.

[0060] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0061] Comparative Examples 1-3

[0062] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0063] (2) Dissolve 45 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0064] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:3:96.90.

[0065] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0066] The catalyst was named 0.1%Ru3%Hpic[Cl] / AC*.

[0067] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0068] Comparative Examples 1-4

[0069] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0070] (2) Dissolve 60 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0071] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:4:95.90.

[0072] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0073] The catalyst was named 0.1%Ru4%Hpic[Cl] / AC*.

[0074] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0075] Example 2 Catalyst Preparation

[0076] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0077] (2) Dissolve 15 mg of pyridine in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain pyridine hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0078] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0079] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0080] The catalyst was named 0.1%Ru1%Py[Cl] / AC*.

[0081] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0082] Example 3 Catalyst Preparation

[0083] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0084] (2) Dissolve 15 mg of piperazine in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain piperazine hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0085] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0086] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0087] The catalyst was named 0.1%Ru1%Pz[Cl] / AC*.

[0088] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0089] Example 4 Catalyst Preparation

[0090] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0091] (2) Dissolve 15 mg of piperidine in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain piperidine hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0092] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0093] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0094] The catalyst was named 0.1%Ru1%Pip[Cl] / AC*.

[0095] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0096] Example 5 Catalyst Preparation

[0097] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0098] (2) Dissolve 15 mg of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid in a molar ratio of 1:1 to the modifier, stir at room temperature for 30 min to obtain 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene hydrochloride, then add 201 μl of RuCl3 mother solution, cover the beaker with a sealing film, and then cover with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0099] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0100] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0101] The catalyst was named 0.1%Ru1%MTBD[Cl] / AC*.

[0102] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0103] Example 6 Catalyst Preparation

[0104] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0105] (2) Dissolve 201 μl of the mother solution in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add 15 mg of benzoic acid and stir at room temperature. Cover the beaker with a sealing film and then cover it with tin foil and stir at 350 rpm for 5 h at room temperature.

[0106] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0107] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0108] The catalyst was named 0.1%Ru1%BA / AC*.

[0109] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0110] Example 7 Catalyst Preparation

[0111] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0112] (2) Dissolve 15 mg of pyrimidine-2-carboxylic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain pyrimidine-2-carboxylic acid hydrochloride, finally add 201 μl of RuCl3 mother solution, cover the beaker with a sealing film, then cover with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0113] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0114] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0115] The catalyst was named 0.1%Ru1%Hpmc[Cl] / AC*.

[0116] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0117] Example 8 Catalyst Preparation

[0118] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0119] (2) Dissolve 15 mg of 2-carboxylic acid pyrazine in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain 2-carboxylic acid pyrazine hydrochloride, finally add 201 μl of RuCl3 mother solution, cover the beaker with a sealing film, then cover with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0120] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0121] (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

[0122] The catalyst was named 0.1%Ru1%Hpyza[Cl] / AC*.

[0123] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0124] Example 9 Catalyst Preparation

[0125] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0126] (2) Dissolve 15 mg of pyridine-2,6-dicarboxylic acid in 3 ml of H2O for dispersion, stir with a magnetic stirrer at 350 rpm at room temperature, then add hydrochloric acid with a molar ratio of hydrochloric acid to modifier of 1:1, stir at room temperature for 30 min to obtain pyridine-2,6-dicarboxylic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature;

[0127] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90.

[0128] (4) Place the ground catalyst in a forced air drying oven and dry it for 12-24 hours.

[0129] The catalyst was named 0.1%Ru1%Hpydc[Cl] / AC*.

[0130] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0131] Comparative Example 1 Catalyst Preparation

[0132] (1) Prepare the precursor solution: First weigh 0.766 g of ruthenium trichloride (RuCl3 ≥ 99%) solid and dissolve it in 10 ml of distilled water. Oscillate and sonicate, and then add the volume to a 50 ml brown round-bottom flask to obtain a RuCl3 mother solution with a Ru content of 7.47 mg / ml.

[0133] (2) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; 201 μl of the ruthenium precursor solution prepared in step (1) was added to pure water to prepare a 3 ml solution, and then evenly added to the activated carbon carrier (AC). The catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium to carrier in the catalyst was 0.1:99.90.

[0134] (3) Place the ground catalyst in a forced air drying oven at 90°C and dry it for 12-24 hours.

[0135] The catalyst was named 0.1%Ru / AC*.

[0136] The steps of using a low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination to produce vinyl chloride are the same as those in Example 1 and will not be repeated here.

[0137] Table 1 Acetylene hydrochlorination reaction activity test

[0138]

[0139] The 0.1wt%Ru1%MTBD[Cl] / AC catalyst of Example 5 was heated to 170h at an acetylene hourly velocity. -1 At T = 180 ° C, the conversion rate of acetylene was 86.1% and the selectivity of vinyl chloride was 99%, but deactivation occurred within 10 hours.

[0140] The 0.1%Ru1%Hpic[Cl] / AC catalyst of Example 1 was -1At T = 180 ° C, the conversion of acetylene was 84.3%, the selectivity of vinyl chloride was 99%, and the activity remained basically unchanged within 10 hours. Compared with the unmodified 0.1%Ru / AC catalyst, the conversion rate increased by 20.9%. Compared with the rapid deactivation of 0.1%Ru1%Py[Cl] / AC in Example 2, the high stability of the 0.1%Ru1%Hpic[Cl] / AC catalyst in Example 1 indicates that the introduction of carboxyl groups enhances the stability of the catalyst, and compared with the low activity of 0.1%Ru1%BA / AC in Example 6, the high activity of the 0.1%Ru1%Hpic[Cl] / AC catalyst indicates that the interaction between Ru and pyridine nitrogen is the main active site.

[0141] The effect of Hpic loading on the catalytic performance of Ru-Hpic / AC catalyst was further studied. It can be seen from Example 1 and Comparative Examples 1-1, 1-2, 1-3, and 1-4 that when the Hpic loading increases from 0.5% to 1%, the acetylene conversion rate of Ru-Hpic[Cl] / AC does not change significantly, but the deactivation rate of the catalyst gradually decreases with the increase of Hpic loading. When the Hpic loading further increases, the catalytic activity gradually decreases and the deactivation rate gradually increases, which may be due to the excessive introduction of Hpic shielding some active sites. Therefore, the optimal Hpic loading is determined to be 1%, that is, m Ru :m Hpic[Cl] =1:10, the catalyst of Example 1 is the best.

Claims

1. A method for using a low-content ruthenium-based catalyst modified with a nitrogen oxide ligand in the hydrochlorination reaction of acetylene, characterized in that : The catalyst was used in the fixed-bed acetylene hydrochlorination reaction to produce vinyl chloride at an acetylene space velocity of 170 h -1 , V (C2H2) / V (HCl) =1:1.05, vinyl chloride is produced under the condition of reaction temperature of 180℃; The method for preparing a low-content ruthenium-based catalyst for acetylene hydrochlorination reaction comprises the following steps: (1) Prepare the precursor solution: first weigh 0.766g of ruthenium trichloride (RuCl3≥99%) solid and dissolve it in 10ml of distilled water, shake and sonicate, and then dilute to a 50ml brown round-bottom flask to obtain RuCl3 mother solution, Ru: 7.47mg / ml; (2) Dissolve 15 mg of 2-picolinic acid in 3 ml of H2O for dispersion, stir at 350 rpm with a magnetic stirrer at room temperature, then add hydrochloric acid at a molar ratio of 1:1 to 2-picolinic acid, stir at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally add 201 μl of RuCl3 mother solution. Cover the beaker with a sealing film, then cover it with tin foil, and stir at 350 rpm for 5 h at room temperature; (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was spread evenly in a mortar; the solution prepared in step (2) was evenly added to the activated carbon carrier, and the catalyst was fully ground in a clockwise direction until the surface was smooth. The mass ratio of ruthenium: modifier: carrier in the catalyst was 0.1:1:98.90; (4) Dry the ground catalyst in a forced air drying oven for 12-24 hours.

2. The method for using the low-content ruthenium-based catalyst modified with nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that: Step (1) using distilled water as a solvent, dissolving an appropriate amount of ruthenium trichloride (RuCl3) solid in distilled water at room temperature, oscillating for 10 minutes using a mixer, and then ultrasonically treating for 30 minutes to prepare a mother solution of RuCl3 of 7.47 mg / ml, and storing it in a sealed container away from light and at low temperature.

3. The method for using the low-content ruthenium-based catalyst modified by nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that : The mass ratio of ruthenium described in step (2) to 2-picolinic acid is 1:

10.

4. The method for using the low-content ruthenium-based catalyst modified by nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that The molar ratio of the hydrochloric acid in step (2) and the molar ratio of the modifier 2-pyridinecarboxylic acid is 1:

1.

5. The method for using the low-content ruthenium-based catalyst modified with nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that : In step (3), the volume ratio of the activated carbon mass to the distilled water used in the ruthenium precursor solution is 1:

2.

6. The method for using the low-content ruthenium-based catalyst modified by nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that The activated carbon in step (3) is in the shape of column, powder or flake, with a particle size of 200 mesh and a specific surface area of ​​1000-1200m 2 / g.

7. The method for using the low-content ruthenium-based catalyst modified by nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that The catalyst after grinding in step (3) should have a smooth surface and then be dried in a 90°C forced air drying oven.

8. The method for using the low-content ruthenium-based catalyst modified with nitrogen oxide ligands according to claim 1 for acetylene hydrochlorination reaction, characterized in that: The specific steps are as follows: (1) Loading the catalyst: 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 the catalyst into the reaction tube and ensure that the catalyst is flat, and then pad it with another layer of quartz wool with a thickness of 10 mm; (2) Before the reaction: The entire pipeline was purged with N2 at a flow rate of 20 mL / min for 60 min to remove air and moisture in the system. At the same time, the temperature was controlled to increase to 150 °C at 5 °C / min and maintained for 30 min, and then increased to 180 °C at 5 °C / min; then, HCl was introduced at a flow rate of V = 20 mL / min and maintained for 30 min, and then the reaction gas was introduced at a flow rate of V(C2H2) = 16 mL / min, V(HCl) = 16.8 mL / min and maintained for 10 min to ensure that the catalyst was in the gas atmosphere of acetylene and hydrogen chloride, and then the reaction gas flow rate was reduced to a ratio of V(C2H2) / V(HCl) = 1:1.

05. After maintaining the reaction flow rate for ten minutes, online detection began; (3) After the reaction: The gaseous product is first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then analyzed online by gas chromatography to evaluate the acetylene conversion rate and selectivity for vinyl chloride.

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