A method for the hydrochlorination of acetylene using a low level ruthenium-based catalyst modified with a nitrenyl ligand

Abstract

This invention relates to a method for using a low-content ruthenium-based catalyst modified with nitrogen and oxygen ligands in the hydrochlorination of acetylene. The invention utilizes 2-pyridine carboxylate as a ligand, commercial activated carbon as a support, trace amounts of ruthenium as the main active component, and water as a solvent. An improved synthesis procedure yields a low-content ruthenium-based catalyst with ruthenium ions coordinated by a modifier and commercial activated carbon as a support, significantly improving catalyst performance while reducing ruthenium content. This catalyst exhibits high activity and vinyl chloride selectivity in the fixed-bed hydrochlorination of acetylene to vinyl chloride, and its low cost makes it highly valuable for industrial applications. The ruthenium loading is 0.1%, and the reaction gas space velocity is 170 h⁻¹. ‑1 V (C2H2) / V (HCl) With a ratio of 1:1.05 and a reaction temperature of 180℃, the acetylene conversion rate can reach 84.3%, the vinyl chloride selectivity is greater than 99%, and the activity remains basically unchanged within 10 hours.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation technology and application, and particularly relates to a preparation of a low-content ruthenium-based catalyst modified by a nitrogen-oxygen ligand and application thereof in an ethyne hydrochlorination reaction. BACKGROUND

[0002] Polyvinyl chloride, as the second largest general resin in the world, is obtained by polymerization of vinyl chloride monomer. It has a wide range of applications in many fields such as building, industry, agriculture, daily necessities, etc. due to its advantages such as wide raw material sources, low cost, and strong performance adjustability. The main method for industrial preparation of vinyl chloride in China is the ethyne method, in which vinyl chloride is directly synthesized by addition of ethyne and hydrogen chloride under the action of a mercury chloride catalyst. This method has simple process and equipment, low investment, and high yield, but has high energy consumption and raw material cost, and the used mercury chloride catalyst seriously harms the environment and human health. At present, the use of HgCl2 catalyst is being gradually restricted in China. Therefore, it is urgent to develop a mercury-free catalyst which is environmentally friendly, non-toxic, and has industrial application value for the production of vinyl chloride by the ethyne hydrochlorination method.

[0003] Based on the discovery of Hutching et al., there is a clear positive correlation between the catalytic activity of metal cations and their standard electrode potentials in the process of ethyne hydrochlorination reaction. Based on this discovery, metals such as Au, Pd, Pt, Ru, Cu, and Bi with high redox potentials have been widely studied. Among them, Au catalyst stands out from many metals due to its excellent catalytic activity. However, with the rise of gold prices in recent years, it has become increasingly difficult to apply Au catalyst to industrial production. The price of Ru is only one-fifth of that 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 ethyne hydrochlorination reaction, RuCl3 has the lowest ethyne hydrochlorination reaction energy barrier compared with AuCl3 and HgCl2. At the same time, with the increasing strictness of environmental protection requirements, ruthenium-based catalysts, as a kind of mercury-free catalyst, have broad application prospects.

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

[0005] Although the above research screens a series of ligands to modify the ruthenium-based catalyst, and inhibits the reduction of high-valence ruthenium species while improving the stability and catalytic activity of the catalyst, ruthenium is a noble metal, and a higher loading will lead to a higher cost of the catalyst. Therefore, how to reduce the ruthenium loading while improving the activity has become the top priority of the industrial application of the ruthenium-based catalyst. SUMMARY

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

[0007] In order to solve the technical problem of the present application, the technical solution is that the catalyst is used in the acetylene hydrochlorination reaction for producing vinyl chloride in a fixed bed, under the condition that the acetylene space velocity is 170 h -1 , V (C2H2) / V (HCl) =1:1.05 and the reaction temperature is 180℃;

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

[0009] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) solid was weighed and dissolved in 10 ml of distilled water, shaken and ultrasonically treated, and then diluted to 50 ml in a brown round-bottom flask to obtain a RuCl3 mother liquor, Ru: 7.47 mg / ml;

[0010] (2) 15 mg of 2-picolinic acid was dissolved in 3 ml of H2O to disperse, and then 1 ml of hydrochloric acid was added at a molar ratio of 1:1 with 2-picolinic acid, and stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally 201 μl of RuCl3 mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at room temperature at 350 rpm for 5 h;

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

[0012] (4) The ground catalyst was placed in a blast drying oven and dried for 12-24 h.

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

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

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

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

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

[0018] Preferably, the ground catalyst in step (3) should be smooth on the surface, and then placed in a 90°C blast drying oven for drying.

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

[0020] (1) Loading catalyst: A layer of quartz wool with a thickness of 10 mm was laid in the middle of a quartz reaction tube with a diameter of 10 mm, catalyst was added into the reaction tube and ensured to be flat, and then a layer of quartz wool with a thickness of 10 mm was laid again.

[0021] (2) Before reaction: The whole 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℃ at a rate of 5℃ / min and maintained for 30 min, and then increased to 180℃ at a rate of 5℃ / min. Then, HCl was passed in at a flow rate of V=20 mL / min and maintained for 30 min, then the reaction gas was passed in 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 in the ratio of V(C2H2) / V(HCl)=1:1.05, and after maintaining for ten minutes at the reaction flow rate, online detection was started.

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

[0023] Beneficial effects:

[0024] The application provides a preparation method of a low-content ruthenium-based catalyst modified by a nitrogen-oxygen ligand. Compared with other methods, the method greatly reduces the preparation cost, is simpler to operate and can be scaled up. The technical scheme adopted by the application is that one or more of (Hpic[Cl]=2-pyridine carboxylate 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) is selected as a ligand modifier to modify the ruthenium-based catalyst, water is selected as a solvent, the content of Ru in the catalyst is greatly reduced, and the low-content ruthenium-based catalyst modified by the nitrogen-oxygen ligand is prepared. The production cost is effectively saved; the catalyst prepared by the application has excellent catalytic performance on the acetylene hydrochlorination reaction and is suitable for industrial production.

[0025] (1) The catalyst uses a nitrogen-containing ligand as a modifier, ruthenium as a main active component, and water as a solvent. The optimal ratio of the modified carbon carrier to the solvent is reasonably controlled: carrier / g:solution / ml=0.5, and the synthesis steps are improved to improve the efficiency of the catalyst.

[0026] (2) The modifier used in the present application: one or more of 2-picolinic 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-pyrazine carboxylic acid hydrochloride, and pyridine-2,6-dicarboxylic acid hydrochloride are selected as ligand modifiers. Under the same conditions, the introduction of nitrogen (oxygen) ligand stabilizes the active ruthenium species by forming stable coordination bonds 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 application is preferably 2-picolinic acid hydrochloride. The loading of ruthenium is lower than the content reported in most existing technologies, only 0.1%, and 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 selectivity of vinyl chloride is greater than 99%, and the activity remains basically unchanged for 10h, which provides a unique and effective solution for the industrial production of vinyl chloride with low cost and high efficiency.

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

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

[0029] (4) The mixed solution in step (3) of the present application is uniformly added to the surface of activated carbon, and the catalyst is ground in a clockwise direction to be smooth within 10min, and then placed in a 90℃ air drying oven for drying. Grinding to smoothness 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 component.

[0030] (5) The 0.1%Ru1%Hpic[Cl] / AC catalyst, the acetylene space velocity is 170h-1 The conversion rate of acetylene was 84.3% and the selectivity of vinyl chloride was 99% under the condition of T=180℃, and the activity remained unchanged within 10h.

[0031] (6) The 0.1wt% Ru1%Hpic[Cl] / AC catalyst of Example 5 had a conversion rate of acetylene of 86.1% and a selectivity of vinyl chloride of 99% under the condition of acetylene space velocity of 170h-1, T=180℃, but deactivation occurred within 10h. -1 The conversion rate of acetylene was 84.3% and the selectivity of vinyl chloride was 99% under the condition of T=180℃, and the activity remained unchanged within 10h. -1 The conversion rate of acetylene was 84.3% and the selectivity of vinyl chloride was 99% under the condition of T=180℃, and the activity remained unchanged within 10h.

[0032] (7) The effect of Hpic loading on the catalytic performance of Ru-Hpic / AC catalyst was further studied. As can be seen from Example 1 and Comparative Examples 1-1, 1-2, 1-3 and 1-4, when the Hpic loading increased from 0.5% to 1%, the conversion rate of acetylene of Ru-Hpic[Cl] / AC changed unobviously, but the deactivation rate of the catalyst gradually decreased with the increase of Hpic loading. When the loading of Hpic was further increased, the catalytic activity gradually decreased and the deactivation rate gradually increased, which might be due to the excessive introduction of Hpic which shielded part of the active sites. Therefore, the optimal Hpic loading was determined to be 1%, i.e. m Ru : m Hpic[Cl] =1:10, and the catalyst of Example 1 was the best. BRIEF DESCRIPTION OF DRAWINGS

[0033] The application will be further described below in conjunction with the drawings.

[0034] Figure 1 The relationship diagram of acetylene conversion rate-reacting time of different ligand modified ruthenium-based catalysts.

[0035] Figure 2 The relationship diagram of selectivity-reacting time of different ligand modified ruthenium-based catalysts. DETAILED DESCRIPTION

[0036] Example 1 Catalyst preparation

[0037] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed and dissolved in 10 ml of distilled water, shaken and ultrasonically treated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml;

[0038] (2) 15 mg of 2-picolinic acid was dissolved in 3 ml of H2O to disperse, and then hydrochloric acid was added at a molar ratio of 1:1 with the modifier, and stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at room temperature at 350 rpm for 5 h;

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

[0040] (4) The ground catalyst was placed in a blast drying oven and dried for 12-24 h.

[0041] (5) The prepared ruthenium-based catalyst was used for the fixed-bed acetylene hydrochlorination reaction to prepare vinyl chloride.

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

[0043] The steps for using the nitrogen-oxygen ligand modified low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination reaction to prepare vinyl chloride are as follows:

[0044] 1. Catalyst loading: a layer of quartz wool with a thickness of 10 mm was placed in the middle of a quartz reaction tube with a diameter of 10 mm, 1.00 g of catalyst was added to the reaction tube and the catalyst was leveled, and then another layer of 10 mm thick quartz wool was placed;

[0045] 2. Before the reaction: the entire pipeline was purged with 20 mL min −1The N2 flow was purged for 60 min to remove the air and moisture in the system, and the temperature was controlled to increase to 150°C at a rate of 5°C / min and maintained for 30 min, and then increased to 180°C at a rate of 5°C / min; then, hydrogen chloride 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 and 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 flow rate of the reaction gas was reduced at a ratio of V(C2H2) = 4 mL / min and V(C2H2) / V(HCl) = 1:1.05, and maintained for ten minutes at the reaction flow rate before detection began;

[0046] 3. After the reaction: the gaseous products were first passed through an absorption bottle containing NaOH solution to remove excess HCl, and then analyzed on-line by gas chromatography to evaluate the acetylene conversion rate and the selectivity to VCM.

[0047] Comparative Example 1-1

[0048] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed and dissolved in 10 ml of distilled water, shaken and ultrasonically treated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, with Ru: 7.47 mg / ml.

[0049] (2) 7.5 mg of 2-picolinic acid was dissolved in 3 ml of H2O to disperse, and then stirred at 350 rpm under magnetic stirring at room temperature, and then hydrochloric acid was added at a molar ratio of 1:1 with the modifier, and stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride, and finally 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm for 5 h at room temperature.

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

[0051] (4) The ground catalyst was placed in a forced air drying oven and dried for 12-24 h.

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

[0053] The low-content ruthenium-based catalyst was used for the acetylene hydrochlorination reaction in a fixed bed, and the steps were the same as in Example 1, which will not be repeated.

[0054] Comparative Example 1-2

[0055] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed and dissolved in 10 ml of distilled water, oscillated and ultrasonicated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml;

[0056] (2) 30 mg of 2-picolinic acid was dissolved in 3 ml of H2O for dispersion, and then 1 ml of hydrochloric acid was added at a molar ratio of 1:1 with the modifier, and stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride. Finally, 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm for 5 h at room temperature;

[0057] (3) Preparation of catalyst by impregnation method: 1.5 g of activated carbon was placed in a mortar and pestle, and the solution prepared in step (2) was added dropwise to the activated carbon carrier, and the catalyst was 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) The ground catalyst was placed in a blast drying oven and dried for 12-24 h.

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

[0060] The low-content ruthenium-based catalyst was used in the ethylene hydrochlorination reaction in a fixed bed, and the steps were the same as in Example 1, which will not be repeated.

[0061] Comparative Example 1-3

[0062] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed and dissolved in 10 ml of distilled water, oscillated and ultrasonicated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml;

[0063] (2) 45 mg of 2-picolinic acid was dissolved in 3 ml of H2O for dispersion, and then 1 ml of hydrochloric acid was added at a molar ratio of 1:1 with the modifier, and stirred at room temperature for 30 min to obtain 2-picolinic acid hydrochloride. Finally, 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm for 5 h at room temperature;

[0064] (3) Catalyst preparation by impregnation method: 1.5 g of activated carbon was laid flat in a mortar; the solution prepared in step (2) was added evenly to the activated carbon carrier, and the catalyst was 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) The ground catalyst was dried in a blast drying oven for 12-24 h.

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

[0067] The steps of using the low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination reaction to prepare vinyl chloride were the same as in Example 1, and are not repeated.

[0068] Comparative Examples 1-4

[0069] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was first dissolved in 10 ml of distilled water, shaken and ultrasonicated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, with a Ru concentration of 7.47 mg / ml.

[0070] (2) 60 mg of 2-picolinic acid was dissolved in 3 ml of H2O to disperse, and then stirred at 350 rpm by a magnetic stirrer at room temperature. Then, hydrochloric acid was added, and the molar ratio of hydrochloric acid to modifier was 1:1. After stirring at room temperature for 30 min, 2-picolinic acid hydrochloride was obtained. Finally, 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper. The stirring was carried out at 350 rpm for 5 h at room temperature.

[0071] (3) Catalyst preparation by impregnation method: 1.5 g of activated carbon was laid flat in a mortar; the solution prepared in step (2) was added evenly to the activated carbon carrier, and the catalyst was 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) The ground catalyst was dried in a blast drying oven for 12-24 h.

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

[0074] The steps of using the low-content ruthenium-based catalyst for the fixed-bed acetylene hydrochlorination reaction to prepare vinyl chloride were the same as in Example 1, and are not repeated.

[0075] Example 2 Catalyst Preparation

[0076] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) solid was weighed into 10 ml of distilled water, shaken and ultrasonicated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml;

[0077] (2) 15 mg of pyridine was dissolved in 3 ml of H2O for dispersion, and then hydrochloric acid was added at a molar ratio of 1:1 with the modifier at room temperature, and stirred for 30 min at room temperature to obtain pyridine hydrochloride, and finally 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm for 5 h at room temperature;

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

[0079] (4) The ground catalyst was dried in a blast drying oven for 12-24 h.

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

[0081] The low-content ruthenium-based catalyst was used for the ethylene hydrochlorination reaction in a fixed bed, and the steps were the same as in Example 1, which will not be repeated.

[0082] Example 3 Catalyst Preparation

[0083] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) solid was weighed into 10 ml of distilled water, shaken and ultrasonicated, and then made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml;

[0084] (2) 15 mg of pyridine was dissolved in 3 ml of H2O for dispersion, and then hydrochloric acid was added at a molar ratio of 1:1 with the modifier at room temperature, and stirred for 30 min at room temperature to obtain pyridine hydrochloride, and finally 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm for 5 h at room temperature;

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

[0086] (4) The ground catalyst was dried in a blast drying oven for 12-24h.

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

[0088] The low content ruthenium-based catalyst was used in the fixed bed acetylene hydrochlorination reaction, and the steps were the same as those in Example 1, which will not be repeated.

[0089] Example 4 Catalyst Preparation

[0090] (1) Preparation of precursor solution: First, 0.766g of ruthenium trichloride (RuCl3≥99%) solid was dissolved in 10ml of distilled water, oscillated, ultrasonicated, and made up to 50ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47mg / ml;

[0091] (2) 15mg of piperidine was dissolved in 3ml of H2O for dispersion, and a magnetic stirrer was used at 350rpm at room temperature, then hydrochloric acid was added, and the molar ratio of hydrochloric acid to modifier was 1:1, and the mixture was stirred at room temperature for 30min to obtain piperidine hydrochloride, and finally 201μl of RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350rpm at room temperature for 5h;

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

[0093] (4) The ground catalyst was dried in a blast drying oven for 12-24h.

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

[0095] The low content ruthenium-based catalyst was used in the fixed bed acetylene hydrochlorination reaction, and the steps were the same as those in Example 1, which will not be repeated.

[0096] Example 5 Catalyst Preparation

[0097] (1) Preparation of precursor solution: First, 0.766g of ruthenium trichloride (RuCl3≥99%) solid was dissolved in 10ml of distilled water, oscillated, ultrasonicated, and made up to 50ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47mg / ml;

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

[0099] (3) Catalyst preparation by impregnation method: take 1.5 g of activated carbon and lay it flat in a mortar; take the solution prepared in step (2) and uniformly drop it onto the activated carbon carrier, and grind the catalyst in a clockwise direction until the surface is smooth, and the mass ratio of ruthenium: modifier: carrier in the catalyst is 0.1:1:98.90.

[0100] (4) Dry the ground catalyst in a blast drying oven for 12-24 h.

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

[0102] The low-content ruthenium-based catalyst is used for the ethyne hydrochlorination reaction in a fixed bed to prepare chloroethylene, and the steps are the same as in Example 1, which will not be repeated.

[0103] Example 6 Catalyst preparation

[0104] (1) Preparation of precursor solution: first, take 0.766 g of ruthenium trichloride (RuCl3≥99%) solid and dissolve it in 10 ml of distilled water, shake and ultrasonic, and then make up to 50 ml in a brown round-bottom flask to obtain a RuCl3 mother liquor, and the concentration of Ru is 7.47 mg / ml;

[0105] (2) Take 201 μl of the mother liquor and dissolve it in 3 ml of H2O for dispersion, and then add 15 mg of benzoic acid at room temperature, stir the beaker with sealing film, cover it with tin foil paper, and stir at 350 rpm at room temperature for 5 h;

[0106] (3) Catalyst preparation by impregnation method: take 1.5 g of activated carbon and lay it flat in a mortar; take the solution prepared in step (2) and uniformly drop it onto the activated carbon carrier, and grind the catalyst in a clockwise direction until the surface is smooth, and the mass ratio of ruthenium: modifier: carrier in the catalyst is 0.1:1:98.90.

[0107] (4) Dry the ground catalyst in a blast drying oven for 12-24 h.

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

[0109] Low Ru-based catalysts for the acetylene hydrochlorination to vinyl chloride reaction in a fixed bed were used in the same way as in Example 1, and are not repeated.

[0110] Example 7 Catalyst preparation

[0111] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed into 10 ml of distilled water, shaken and ultrasonically treated, and made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml.

[0112] (2) 15 mg of pyrimidine-2-carboxylic acid was dissolved in 3 ml of H2O to disperse, and stirred at 350 rpm using a magnetic stirrer at room temperature, then hydrochloric acid was added, the molar ratio of hydrochloric acid to modifier was 1:1, and stirred at room temperature for 30 min to obtain pyrimidine-2-carboxylic acid hydrochloride, and finally 201 μl of the RuCl3mother liquor was added, the beaker was covered with a sealing film, and then covered with tin foil paper, and stirred at 350 rpm at room temperature for 5 h.

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

[0114] (4) The ground catalyst was placed in a blast drying oven and dried for 12-24 h.

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

[0116] Low Ru-based catalysts for the acetylene hydrochlorination to vinyl chloride reaction in a fixed bed were used in the same way as in Example 1, and are not repeated.

[0117] Example 8 Catalyst preparation

[0118] (1) Preparation of precursor solution: 0.766 g of ruthenium trichloride (RuCl3≥99%) was weighed into 10 ml of distilled water, shaken and ultrasonically treated, and made up to 50 ml in a brown round-bottom flask to obtain a RuCl3mother liquor, Ru: 7.47 mg / ml.

[0119] (2) Take 15 mg of 2-pyrazinecarboxylic acid and dissolve it in 3 ml of H2O to disperse, then add hydrochloric acid, the molar ratio of hydrochloric acid to modifier is 1:1, stir for 30 min at room temperature, to obtain 2-pyrazinecarboxylic acid hydrochloride, finally add 201 μl of RuCl3 mother liquor, cover the beaker with sealing film, cover it with tin foil paper, stir at 350 rpm for 5 h at room temperature;

[0120] (3) Catalyst prepared by impregnation method: take 1.5 g of activated carbon and lay it flat in a mortar; take the solution prepared in step (2) and evenly drop it onto the activated carbon carrier, and grind the catalyst in a clockwise direction until the surface is smooth, the mass ratio of ruthenium: modifier: carrier in the catalyst is 0.1:1:98.90.

[0121] (4) Dry the ground catalyst in a blast drying oven for 12-24 h.

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

[0123] Low-content ruthenium-based catalyst is used for the ethylene hydrochlorination reaction in a fixed bed, and the steps are the same as in Example 1, which will not be repeated.

[0124] Example 9 Catalyst preparation

[0125] (1) Prepare the precursor solution: first, take 0.766 g of ruthenium trichloride (RuCl3≥99%) solid and dissolve it in 10 ml of distilled water, shake and ultrasonic, and then make up to 50 ml in a brown round-bottom flask to obtain a RuCl3 mother liquor, Ru: 7.47 mg / ml;

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

[0127] (3) Catalyst prepared by impregnation method: take 1.5 g of activated carbon and lay it flat in a mortar; take the solution prepared in step (2) and evenly drop it onto the activated carbon carrier, and grind the catalyst in a clockwise direction until the surface is smooth, the mass ratio of ruthenium: modifier: carrier in the catalyst is 0.1:1:98.90.

[0128] (4) Dry the ground catalyst in a blast drying oven for 12-24 h.

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

[0130] The procedure of acetylene hydrochlorination reaction over low Ru-based catalyst in fixed bed is the same as example 1, and is not repeated here.

[0131] Preparation of catalyst in comparative example 1

[0132] (1) Preparation of precursor solution: 0.766g of ruthenium trichloride (RuCl3≥99%) was weighed and dissolved in 10ml of distilled water, and then oscillated and ultrasonicated. The solution was diluted to 50ml in a brown round-bottom flask to obtain a RuCl3mother liquor, with Ru: 7.47mg / ml.

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

[0134] (3) The ground catalyst was placed in a blast drying oven at 90°C for 12-24h.

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

[0136] The procedure of acetylene hydrochlorination reaction over low Ru-based catalyst in fixed bed is the same as example 1, and is not repeated here.

[0137] Table 1 Activity test of acetylene hydrochlorination reaction

[0138]

[0139] The 0.1wt%Ru1%Hpydc[Cl] / AC catalyst of example 5 has an acetylene conversion rate of 86.1% and a vinyl chloride selectivity of 99% under the condition of acetylene space velocity of 170h-1 and T=180°C, but it is deactivated within 10h. -1

[0140] The 0.1%Ru1%Hpic[Cl] / AC catalyst of example 1 has an acetylene conversion rate of 86.1% and a vinyl chloride selectivity of 99% under the condition of acetylene space velocity of 170h-1 and T=180°C, but it is deactivated within 10h. -1 ​, T = 180 °C, the conversion of ethyne was 84.3% and the selectivity of vinyl chloride was 99%, and the activity remained unchanged within 10 h. Compared with the unmodified 0.1% Ru / AC catalyst, the conversion was increased by 20.9%. Compared with the rapid deactivation of the 0.1% Ru1%Py[Cl] / AC catalyst of Example 2, the high stability of the 0.1% Ru1%Hpic[Cl] / AC catalyst of Example 1 indicated that the introduction of carboxyl groups enhanced the stability of the catalyst, and compared with the low activity of the 0.1% Ru1%BA / AC catalyst of Example 6, the high activity of the 0.1% Ru1%Hpic[Cl] / AC catalyst indicated that the interaction of Ru and pyridine nitrogen was the main active site.

[0141] The effect of Hpic loading on the catalytic performance of Ru-Hpic / AC catalysts was further studied. As can be seen from Example 1 and Comparative Examples 1-1, 1-2, 1-3 and 1-4, when the Hpic loading increased from 0.5% to 1%, the conversion of ethyne of the Ru-Hpic[Cl] / AC catalyst changed insignificantly, but the deactivation rate of the catalyst gradually decreased with the increase of Hpic loading. When the loading of Hpic was further increased, the catalytic activity gradually decreased and the deactivation rate gradually increased, which was probably due to the excessive introduction of Hpic which shielded part of the active sites. Therefore, the optimal Hpic loading was determined to be 1%, i.e. m Ru : m Hpic[Cl] = 1:10, and the catalyst of Example 1 was the best.

Claims

1. A process for the hydrochlorination of acetylene using a low level ruthenium based catalyst modified with a nitrenyl ligand, characterized in that : The catalyst is used in the production of vinyl chloride by acetylene hydrochlorination in a fixed bed, under the conditions of acetylene space velocity 170 h -1 , V (C2H2) / (HCl) = 1:1.05, reaction temperature 180℃. The preparation method of the low content ruthenium-based catalyst for the acetylene hydrochlorination reaction comprises the following steps: (1) Prepare a precursor solution: first, weigh 0.766 g of ruthenium trichloride solid and dissolve it in 10 ml of distilled water, shake and ultrasonic, and then dilute to 50 ml in a brown round-bottom flask to obtain a RuCl3 mother liquor, Ru: 7.47 mg / ml; (2) Take 15 mg of 2-picolinic acid and dissolve it in 3 ml of H2O for dispersion, then add hydrochloric acid with a molar ratio of 1:1, stir at room temperature for 30 min, and then add 201 μl of the RuCl3 mother liquor, cover the beaker with a sealing film, and then cover it with tin foil paper, and stir at 350 rpm at room temperature for 5 h; (3) Prepare the catalyst by impregnation method: take 1.5 g of activated carbon and lay it in a mortar; take the solution prepared in step (2) and evenly drop it onto the activated carbon carrier, and grind the catalyst in a clockwise direction until the surface is smooth, and the mass ratio of ruthenium: modifier: carrier in the catalyst is 0.1:1:98.90; (4) Dry the ground catalyst in a blast drying oven for 12-24 h.

2. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that: Step (1) uses distilled water as the solvent, dissolves an appropriate amount of ruthenium trichloride RuCl3 solid in distilled water at room temperature, uses a mixing instrument to shake for 10 min, and then ultrasonically treats for 30 min, to prepare a RuCl3 mother liquor with a concentration of 7.47 mg / ml, which is sealed, protected from light, and stored at low temperature.

3. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that The mass ratio of ruthenium to 2-picolinic acid in step (2) is 1:

10.

4. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that The molar ratio of hydrochloric acid to modifier 2-picolinic acid in step (2) is 1:

1.

5. The process for the hydrochlorination of acetylene using the low level ruthenium based catalyst modified with the nitrenes ligand as claimed in claim 1, wherein the process is carried out at a temperature in the range of 50- 100°C, preferably 60- 80°C. The volume ratio of activated carbon to distilled water used for the ruthenium precursor solution in step (3) is 1:

2.

6. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that The shape of the activated carbon in step (3) is cylindrical, powdered or flaky, the particle size is 200 mesh, and the specific surface area is 1000-1200 m 2 / g.

7. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that The ground catalyst in step (3) should ensure a smooth surface, and then be placed in a 90°C blast drying oven for drying.

8. Process for the hydrochlorination of acetylene using the low- ruthenium catalyst modified with nitrenes according to claim 1, characterized in that: The specific steps are as follows: (1) Load 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 to the reaction tube and ensure that the catalyst is flat, and then pad another layer of 10 mm thick quartz wool; (2) Before the reaction: the entire pipeline is 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, control the temperature, increase to 150°C at a rate of 5°C / min and maintain for 30 min, then increase to 180°C at a rate of 5°C / min; then, pass in HCl at a flow rate of V=20 mL / min and maintain for 30 min, then pass in the reaction gas at a flow rate of V(C2H2)=16 mL / min, V(HCl)=16.8 mL / min and maintain for 10 min, to ensure that the catalyst is in an acetylene and hydrogen chloride gas atmosphere, and then reduce the reaction gas flow rate in the ratio of V(C2H2) / V(HCl)=1:1.05, maintain for ten minutes, and then start online detection; (3) After reaction: The gaseous products first pass through an absorption bottle containing NaOH solution to remove excess HCl, and then are analyzed on-line by gas chromatography to evaluate the conversion of acetylene and the selectivity to vinyl chloride.

Images