A catalyst for liquid-phase synthesis of vinyl chloride from acetylene, a preparation method and application thereof

Abstract

The application belongs to the technical field of catalysts, and particularly relates to a catalyst for liquid-phase synthesis of chloroethylene from acetylene as well as a preparation method and application thereof. The raw material of the catalyst for liquid-phase synthesis of chloroethylene from acetylene comprises imidazole ionic liquid, metal chloride and quaternary phosphonium salt organic ligand additives. The application uses ionic liquid as a reaction medium, adds an organic ligand to complex a metal active component, and prepares a liquid-phase catalyst, so that the dispersity of the metal active component is greatly improved, the reduction of the active component is inhibited, the catalyst activity and stability are improved, the liquid-phase catalyst can avoid local excessively high temperature, the heat removal capacity requirement of the equipment is reduced, and the catalyst has a high industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, specifically relating to a catalyst for the liquid-phase synthesis of vinyl chloride from acetylene, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC) resin is one of the five major general-purpose plastics, widely used in industry, agriculture, construction, and technology. PVC is polymerized from vinyl chloride monomer (VCM), and the main synthesis methods for VCM monomer include the acetylene process, the ethylene process, and the oxychlorination processes of ethylene and ethane. Industrially, the acetylene process uses a mercury-containing catalyst system. However, due to the increasing depletion of mercury resources and the serious harm mercury causes to the environment and human health, the international community encourages the development of mercury-free catalysts. The development of mercury-free catalysts has almost entirely focused on solid catalysts. However, solid catalysts, due to their high activity and large heat release during use, often experience excessively high local temperatures, leading to problems such as catalyst sintering and carbon deposition. This affects the gas-solid mass transfer efficiency of the catalyst, ultimately reducing its activity and shortening its lifespan. Based on this, researchers have begun to introduce liquid-phase catalysts for the acetylene hydrochlorination reaction. Compared with gas-solid phase reactions, gas-liquid phase reactions have the advantages of uniform temperature and excellent mass transfer.

[0003] Chinese invention patent application CN115945214A discloses a liquid-phase catalytic solution for the hydrochlorination of acetylene to synthesize vinyl chloride, its uses, and a method, apparatus, and application method for synthesizing vinyl chloride. The liquid-phase catalytic solution comprises a liquid-phase non-metallic solution and a liquid-phase metallic catalytic solution. The liquid-phase non-metallic catalytic solution comprises a first component and a second component. The first component is one of an imidazole compound and an imidazole chloride salt, and the second component is an amide. The liquid-phase metallic catalytic solution is based on the liquid-phase non-metallic catalytic solution with the addition of a metal chloride. Catalytic performance evaluation shows that the liquid-phase catalyst exhibits high activity. However, this invention suffers from problems such as long process flow, high energy consumption, and poor desorption effect because the absorption of hydrogen chloride and the desorption of vinyl chloride are carried out separately.

[0004] Another Chinese invention patent application, CN105148989A, discloses a porous solid material supported ionic liquid-gold catalyst and its preparation and application. The catalyst includes a porous solid material support and a composite of an ionic liquid and a metal ion compound supported on the surface of the support. The porous solid material supported ionic liquid-gold catalyst of this invention has the characteristics of high catalytic activity and selectivity, good stability, and low cost. However, the reaction zone is relatively narrow, the reaction heat is difficult to escape, the local temperature is difficult to control, and the mercuric chloride in the catalyst sublimates quickly, resulting in a short catalyst life, high consumption, and great harm to the environment. At the same time, the activated carbon is prone to degradation.

[0005] The invention described above demonstrates the feasibility of liquid-phase catalysis. However, the reaction temperature of the system is generally higher than the boiling point of ordinary solvents, which leads to the loss of liquid-phase catalyst and seriously affects the catalyst activity. Therefore, finding a suitable reaction medium is the key to the liquid-phase reaction of acetylene hydrochlorination. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing a catalyst for the liquid-phase synthesis of vinyl chloride from acetylene, its preparation method, and its application.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A catalyst, wherein the raw materials for the catalyst include imidazole ionic liquids, metal chlorides, and quaternary phosphine salt organic ligands.

[0009] Preferably, the organic ligand auxiliary is selected from any one of tetraphenylphosphine bromide, methyltriphenylphosphine bromide, ethyltriphenylphosphine bromide, propyltriphenylphosphine bromide, tetraphenylphosphine chloride, methyltriphenylphosphine chloride, ethyltriphenylphosphine chloride, and propyltriphenylphosphine chloride.

[0010] Preferably, the imidazole ionic liquid is selected from any one of the imidazole chloride ionic liquids with hydrogen groups in C1-C6 alkyl-substituted amino groups, and the metal chloride is selected from one or more of gold chloride, ruthenium chloride, palladium chloride, copper chloride, bismuth chloride, and tin chloride.

[0011] Preferably, the molar ratio of the metal chloride, ionic liquid, and organic ligand auxiliaries is 0.5-10:100:5-20.

[0012] The present invention also provides a method for preparing the above-mentioned catalyst, comprising the following steps:

[0013] (1) Stir the imidazole ionic liquid to obtain solution A;

[0014] (2) Mix the metal chloride with the quaternary phosphine salt organic ligand auxiliaries to obtain solution B;

[0015] (3) Then mix solution A with solution B to obtain the catalyst.

[0016] Preferably, the stirring time in step (1) is 0.5-2 hours, the stirring temperature is 80-140°C, and the stirring speed is 100-700 rpm. More preferably, the stirring time is 1-2 hours, the stirring temperature is 100-120°C, and the stirring speed is 200-500 rpm.

[0017] Preferably, in step (2), the mixture is stirred after mixing, the stirring temperature is 30-80℃, the stirring time is 0.5-2h, and water is added during mixing. More preferably, the stirring temperature is 40-60℃, and the stirring time is 1-2h.

[0018] Preferably, the mixing temperature in step (3) is 100-140°C, and the mixing time is 2-12 hours. More preferably, the mixing temperature is 120°C, and the mixing time is 5-10 hours.

[0019] The present invention also provides the application of the above-mentioned catalyst in the hydrochlorination reaction of acetylene.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention uses ionic liquid as reaction medium and adds organic ligands to complex metal active components, which greatly improves the dispersion of metal active components and inhibits the reduction of active components, especially reducing the reduction effect of hydrogen on active components in actual industrial conditions.

[0022] (2) The catalyst of the present invention is simple to prepare and can ensure the uniformity of the catalyst.

[0023] (3) The reaction temperature is uniform during the reaction process, avoiding the problem of catalyst sintering and carbon buildup, which can extend the service life of the catalyst and reduce the production cost of PVC. Detailed Implementation

[0024] It is worth noting that the raw materials used in this invention are all commercially available products.

[0025] Example 1

[0026] 20 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 500 rpm for 1 h at 120 °C with a magnetic stir bar. Simultaneously, 0.13 g of ruthenium chloride and 1 g of methyltriphenylphosphine bromide were weighed and placed in a beaker with a ruthenium loading of 0.25%, and 5 g of deionized water was added. The mixture was stirred at 60 °C for 1 h. Then, the mixed solution containing the metal chloride was slowly added to the ionic liquid, and stirring was continued at 120 °C for 5 h to obtain liquid-phase catalyst A.

[0027] Example 2

[0028] 20 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 300 rpm for 2 h at 100 °C with a magnetic stir bar. Simultaneously, 0.13 g of ruthenium chloride and 1.5 g of tetraphenylphosphine bromide were weighed and placed in a beaker with a ruthenium loading of 0.25%, and 5 g of deionized water was added. The mixture was stirred at 40 °C for 2 h. Then, the mixed solution containing the metal chloride was slowly added to the ionic liquid, and stirring was continued at 120 °C for 5 h to obtain liquid-phase catalyst B.

[0029] Example 3

[0030] 20 g of 1-methyl-3-imidazolium chloride was weighed and placed in a beaker, and stirred at 500 rpm for 1 h at 110 °C with a magnetic stir bar. Simultaneously, 0.17 g of gold chloride and 1.5 g of propyltriphenylphosphine chloride were weighed and placed in a beaker with a gold loading of 0.2%, and 5 g of deionized water was added. The mixture was stirred at 50 °C for 1 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring was continued at 120 °C for 5 h to obtain liquid-phase catalyst C.

[0031] Example 4

[0032] 20 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 350 rpm for 1.5 h at 120 °C with a magnetic stir bar. Simultaneously, 2.66 g of bismuth chloride and 1.5 g of tetraphenylphosphine chloride, with a bismuth loading of 5%, were weighed and placed in a beaker, along with 8 g of deionized water, and stirred at 60 °C for 2 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring continued at 120 °C for 10 h to obtain liquid-phase catalyst D.

[0033] Example 5

[0034] 40 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 300 rpm for 2 h at 120 °C with a magnetic stir bar. Simultaneously, 0.05 g of ruthenium chloride, 5.3 g of copper chloride, and 3 g of methyltriphenylphosphine bromide were weighed and placed in a beaker with a copper loading of 5% and a ruthenium loading of 0.05%, and 15 g of deionized water was added. The mixture was stirred at 60 °C for 1 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring was continued at 120 °C for 10 h to obtain liquid-phase catalyst E.

[0035] Example 6

[0036] 40 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 300 rpm for 2 h at 120 °C with a magnetic stir bar. Simultaneously, 0.09 g of gold chloride, 5.3 g of copper chloride, and 3 g of tetraphenylphosphine bromide were weighed and placed in a beaker with a copper loading of 5% and a gold loading of 0.05%, and 15 g of deionized water was added. The mixture was stirred at 60 °C for 1 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring was continued at 120 °C for 10 h to obtain liquid-phase catalyst F.

[0037] Example 7

[0038] 20 g of 1-hexyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 700 rpm for 1 h at 120 °C with a magnetic stir bar. Simultaneously, 0.085 g of palladium chloride and 1.5 g of ethyltriphenylphosphine chloride were weighed and placed in a beaker with a palladium loading of 0.25%, and 5 g of deionized water was added. The mixture was stirred at 60 °C for 1 h. Then, the mixed solution containing the metal chloride was slowly added to the ionic liquid, and stirring was continued at 120 °C for 5 h to obtain liquid-phase catalyst G.

[0039] Comparative Example 1

[0040] 40 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 300 rpm for 2 h at 120 °C with a magnetic stir bar. Simultaneously, 0.05 g of ruthenium chloride and 5.3 g of copper chloride were weighed and placed in a beaker with 15 g of deionized water, according to a copper loading of 5% and a ruthenium loading of 0.05%, and stirred at 60 °C for 1 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring continued at 120 °C for 10 h to obtain the liquid-phase catalyst C1.

[0041] Comparative Example 2

[0042] 40 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker. A magnetic stir bar was added, and the mixture was stirred at 300 rpm for 2 h at 120 °C. With a copper loading of 5% and a ruthenium loading of 0.05%, 0.05 g of ruthenium chloride, 5.3 g of copper chloride, and 3 g of methyltriphenylphosphine bromide were weighed and placed in a beaker, along with 15 g of deionized water. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and the mixture was stirred at 120 °C for another 10 h to obtain the liquid-phase catalyst C2.

[0043] Comparative Example 3

[0044] 30g of activated carbon was weighed and placed in a beaker. A solution was prepared with a ruthenium loading of 0.25%, a methyltriphenylphosphine bromide loading of 0.5%, and a 1-butyl-3-methylimidazolium chloride loading of 5%, using measured amounts of ruthenium chloride, methyltriphenylphosphine bromide, and 1-butyl-3-methylimidazolium chloride to achieve a volume equivalent to the water absorption of 30g of activated carbon. This solution was added to the carrier dropwise while stirring. After titration, the solution was impregnated at 25℃ for 12 hours, and then dried in an oven at 120℃ for 12 hours to obtain the liquid-phase catalyst C3.

[0045] Comparative Example 4

[0046] 20 g of 1-butyl-3-methylimidazolium chloride was weighed and placed in a beaker, and stirred at 500 rpm for 1 h at 120 °C with a magnetic stir bar. Simultaneously, 0.13 g of ruthenium chloride and 1 g of polyethylene glycol were weighed and placed in a beaker with a ruthenium loading of 0.25%, and 5 g of deionized water was added. The mixture was stirred at 60 °C for 1 h. The mixed solution containing the metal chloride was then slowly added to the ionic liquid, and stirring continued at 120 °C for 5 h to obtain the liquid-phase catalyst C4.

[0047] The prepared catalyst was evaluated for its activity and selectivity using the following method:

[0048] The liquid-phase catalysts prepared in Examples 1-7 and Comparative Examples 1-4 were sequentially transferred to a glass-jacketed bubbling reaction tube, hydrogen chloride was introduced and the temperature was raised to 120°C for 1 hour for activation treatment, and then acetylene was introduced and activated at 150°C for 90 hours. -1 The reaction was carried out with HCl / C2H2 at a volume ratio of 1.08. The reaction tail gas was analyzed to obtain the acetylene conversion rate and vinyl chloride selectivity.

[0049] The evaluation results of the catalyst are shown in Table 1 below. Based on the data comparison in Table 1, it can be concluded that the liquid-phase catalyst prepared in the embodiments of this application exhibits a high acetylene conversion rate in the acetylene hydrochlorination reaction, achieving a conversion rate within 90 h⁻¹. -1 Under acetylene space velocity conditions, the acetylene conversion rate was greater than 90%, and the vinyl chloride selectivity was greater than 99%. In particular, the catalyst system composed of precious metals and copper exhibited high low-temperature activity.

[0050] Table 1 Catalytic effect of the catalyst of the present invention

[0051]

[0052] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A catalyst, characterized in that, The catalyst's raw materials include imidazole ionic liquids, metal chlorides, and quaternary phosphine salt organic ligand promoters. The imidazole ionic liquid is 1-methyl-3-imidazolium chloride, 1-butyl-3-methylimidazolium chloride, or 1-hexyl-3-methylimidazolium chloride. The organic ligand promoter is selected from any one of tetraphenylphosphine bromide, tetraphenylphosphine chloride, ethyltriphenylphosphine chloride, and propyltriphenylphosphine chloride. The method for preparing the catalyst includes the following steps: (1) Stir the imidazole ionic liquid to obtain solution A; (2) Mix the metal chloride with the quaternary phosphine salt organic ligand auxiliaries to obtain solution B; (3) Then mix solution A with solution B to obtain the catalyst; In step (2), water is added during mixing, and stirring is performed after mixing. The stirring temperature is 40°C, 50°C, or 60°C, and the stirring time is 1 h or 2 h. The metal chloride is selected from one or more of gold chloride, ruthenium chloride, palladium chloride, copper chloride, bismuth chloride, and tin chloride.

2. The catalyst according to claim 1, characterized in that, The molar ratio of the metal chloride, ionic liquid, and organic ligand auxiliaries is 0.5-10:100:5-20.

3. A method for preparing the catalyst according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Stir the imidazole ionic liquid to obtain solution A; (2) Mix the metal chloride with the quaternary phosphine salt organic ligand auxiliaries to obtain solution B; (3) Then mix solution A with solution B to obtain the catalyst; In step (2), water is added during mixing, and the mixture is stirred after mixing. The stirring temperature is 40℃, 50℃ or 60℃, and the stirring time is 1 h or 2 h.

4. The preparation method according to claim 3, characterized in that, The stirring time in step (1) is 0.5-2 hours, the stirring temperature is 80-140℃, and the stirring speed is 100-700 rpm.

5. The preparation method according to claim 4, characterized in that, The stirring time in step (1) is 1-2 h, the stirring temperature is 100-120℃, and the stirring speed is 200-500 rpm.

6. The preparation method according to claim 3, characterized in that, The mixing temperature in step (3) is 100-140℃, and the mixing time is 2-12 h.

7. The preparation method according to claim 6, characterized in that, The mixing time in step (3) is 5-10 h.

8. The application of a catalyst as described in any one of claims 1-2 or a catalyst prepared by the preparation method as described in any one of claims 3-7 in the hydrochlorination reaction of acetylene.

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