Deep eutectic solvent modified mercury-free catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of synthesis of organic catalysts, and particularly relates to a deep-eutectic solvent modified mercury-free catalyst as well as a preparation method and application thereof. The invention provides a deep-eutectic solvent modified mercury-free catalyst. The deep-eutectic solvent modified mercury-free catalyst comprises an activated carbon carrier, an active component and a deep-eutectic solvent, wherein the active component is located in the activated carbon carrier and on the surface of the activated carbon carrier; the active component is a metal halide and / or a metal complex; metal elements in the metal halide or the metal complex are one or more of gold, palladium, platinum, ruthenium, rhodium, silver, copper and bismuth; the loading capacity of the deep-eutectic solvent in the deep-eutectic solvent modified mercury-free catalyst is 1 to 20 weight percent. The eutectic solvent modified mercury-free catalyst provided by the invention is high in catalytic activity, does not contain mercury in the composition, and is friendly to the environment and human bodies.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic catalyst synthesis, and in particular relates to a deep eutectic solvent modified mercury-free catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the world's three major engineering plastics. With advantages such as flame retardancy and excellent electrical insulation, it is widely used in medical, building materials, packaging, and other fields. The raw material for PVC is vinyl chloride, and its synthesis methods mainly include the ethylene method, the ethane method, and the acetylene method. Currently, the acetylene method, which uses coal as a raw material, is widely used in industry to produce vinyl chloride. However, this method uses a mercury-coal catalyst. The active component of this catalyst, mercuric chloride, easily sublimates at high temperatures, resulting in low catalytic efficiency and harmful effects on the environment and human health. Summary of the Invention

[0003] The purpose of the present invention is to provide a deep eutectic solvent modified mercury-free catalyst and its preparation method and application. The deep eutectic solvent modified mercury-free catalyst provided by the present invention is not only environmentally friendly but also has good catalytic activity for the synthesis of vinyl chloride.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a deep eutectic solvent modified mercury-free catalyst, comprising an activated carbon carrier, active components located in the internal pores and on the surface of the activated carbon carrier, and a deep eutectic solvent;

[0006] The active component is a metal halide and / or a metal complex; the metal element in the metal halide or metal complex is one or more of gold, palladium, platinum, ruthenium, rhodium, silver, copper and bismuth;

[0007] The loading amount of the deep eutectic solvent in the deep eutectic solvent-modified mercury-free catalyst is 1 to 20 wt.%.

[0008] Preferably, the activated carbon carrier is one or more of coconut shell activated carbon, wood activated carbon and coal activated carbon.

[0009] Preferably, the hydrogen bond acceptor of the deep eutectic solvent is a quaternary ammonium ionic liquid and / or an imidazole ionic liquid; and the hydrogen bond donor is one or more of urea, acetamide, N-methylformamide and benzamide.

[0010] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor in the deep eutectic solvent is 0.5 to 2.0:1.

[0011] Preferably, the active component loading amount in the deep eutectic solvent modified mercury-free catalyst is 0.1 to 20 wt.%.

[0012] The present invention also provides a method for preparing the deep eutectic solvent-modified mercury-free catalyst described in the above technical solution, comprising the following steps:

[0013] pre-treating the activated carbon to obtain an activated carbon carrier;

[0014] mixing a hydrogen bond donor and a hydrogen bond acceptor and subjecting the mixture to heat treatment to obtain a deep eutectic solvent;

[0015] A mixed solution of the deep eutectic solvent and the active component is loaded onto an activated carbon carrier to obtain the deep eutectic solvent-modified mercury-free catalyst.

[0016] Preferably, the pretreatment includes crushing and screening the activated carbon, pickling, filtering, washing with water and drying in sequence; the pickling reagent is a hydrochloric acid solution; the drying temperature is 60-70° C.; and the drying time is 8-10 hours.

[0017] Preferably, the heat treatment temperature is 70-90° C., and the heat treatment time is 5 hours; the loading method is ultrasound-assisted impregnation; the ultrasound-assisted impregnation temperature is 20-35° C., and the time is 60-90 minutes.

[0018] The present invention also provides the use of the deep eutectic solvent-modified mercury-free catalyst described in the above technical solution or the deep eutectic solvent-modified mercury-free catalyst prepared by the above preparation method in acetylene hydrochlorination reaction.

[0019] The present invention also provides a method for preparing vinyl chloride, comprising the following steps:

[0020] The catalyst is fixed in a fixed bed reactor, and acetylene and hydrogen chloride are used as raw materials to carry out a catalytic reaction to obtain vinyl chloride; the catalyst is the deep eutectic solvent-modified mercury-free catalyst described in the above technical solution or the deep eutectic solvent-modified mercury-free catalyst prepared by the above preparation method.

[0021] The present invention provides a low eutectic solvent modified mercury-free catalyst, comprising an activated carbon support, an active component located in the internal pores and surface of the activated carbon support, and a low eutectic solvent; the active component is a metal halide and / or a metal complex; the metal element in the metal halide or metal complex is one or more of gold, palladium, platinum, ruthenium, rhodium, silver, copper and bismuth; the loading amount of the low eutectic solvent in the low eutectic solvent modified mercury-free catalyst is 1 to 20 wt.%. The low eutectic solvent modified mercury-free catalyst provided by the present invention improves the dispersion of active metals and can provide more active sites for reaction. The modification of the low eutectic solvent significantly improves the reduction and loss problems of active metals during the catalytic reaction. Therefore, it has high catalytic activity for the synthesis of vinyl chloride by acetylene hydrochlorination, and does not contain mercury in the composition, which is friendly to the environment and the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 IR spectra of the deep eutectic solvent and its hydrogen bond donor and hydrogen bond acceptor obtained in Example 1;

[0024] Figure 2 1 is a graph showing the relationship between acetylene conversion and reaction time for the catalysts prepared in Examples 1 and 3 to 5;

[0025] Figure 3 The relationship between vinyl chloride selectivity and reaction time of the catalysts prepared in Examples 1 and 3 to 5 is shown;

[0026] Figure 4 1 is a graph showing the relationship between acetylene conversion and reaction time of the catalyst prepared in Example 2;

[0027] Figure 5 This is a graph showing the relationship between vinyl chloride selectivity and reaction time for the catalyst prepared in Example 2. DETAILED DESCRIPTION

[0028] The present invention provides a deep eutectic solvent modified mercury-free catalyst, comprising an activated carbon carrier, active components located in the internal pores and on the surface of the activated carbon carrier, and a deep eutectic solvent;

[0029] The active component is a metal halide and / or a metal complex; the metal element in the metal halide or metal complex is one or more of gold, palladium, platinum, ruthenium, rhodium, silver, copper and bismuth; and the loading amount of the deep eutectic solvent in the deep eutectic solvent-modified mercury-free catalyst is 1 to 20 wt.%.

[0030] As an embodiment of the present invention, the activated carbon carrier can be one or more of coconut shell activated carbon, wood activated carbon, or coal-based activated carbon. As an embodiment of the present invention, the active component loading in the deep eutectic solvent-modified mercury-free catalyst can be 0.1 to 20 wt.%.

[0031] In one embodiment of the present invention, the hydrogen bond acceptor of the deep eutectic solvent may be a quaternary ammonium ionic liquid and / or an imidazolium ionic liquid; the hydrogen bond donor may be one or more of urea, acetamide, N-methylformamide, and benzamide. In one embodiment of the present invention, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor in the deep eutectic solvent may be 0.5 to 2.0:1.

[0032] The present invention also provides a method for preparing the deep eutectic solvent-modified mercury-free catalyst described in the above technical solution, comprising the following steps:

[0033] pre-treating the activated carbon to obtain an activated carbon carrier;

[0034] mixing a hydrogen bond donor and a hydrogen bond acceptor and subjecting the mixture to heat treatment to obtain a deep eutectic solvent;

[0035] A mixed solution of the deep eutectic solvent and the active component is loaded onto an activated carbon carrier to obtain the deep eutectic solvent-modified mercury-free catalyst.

[0036] The present invention pre-treats activated carbon to obtain an activated carbon carrier;

[0037] As an embodiment of the present invention, the pretreatment includes crushing and screening the activated carbon, pickling, filtering, washing with water, and drying in sequence. As an embodiment of the present invention, the acid for pickling is a hydrochloric acid solution; the concentration of the hydrochloric acid solution can be 1 to 4 mol / L, specifically 3 mol / L. As an embodiment of the present invention, the water washing can be performed to neutrality. As an embodiment of the present invention, the drying temperature can be 60 to 70°C, specifically 60°C, 65°C, or 70°C; the drying time can be 8 to 10 hours, specifically 8 hours, 9 hours, or 10 hours.

[0038] The invention mixes a hydrogen bond donor and a hydrogen bond acceptor, and performs heat treatment to obtain a deep eutectic solvent.

[0039] As an embodiment of the present invention, the temperature of the heat treatment can be 70-90°C, specifically 70°C, 80°C or 90°C, and the heat treatment time can be 5 hours. As an embodiment of the present invention, the heat treatment can be water bath heating. As an embodiment of the present invention, the heat treatment further includes drying, and the drying temperature can be 120°C, and the drying time can be 10 hours.

[0040] The present invention loads a mixed solution of a deep eutectic solvent and an active component onto an activated carbon carrier to obtain the deep eutectic solvent-modified mercury-free catalyst.

[0041] As an embodiment of the present invention, the loading method is ultrasound-assisted impregnation; the temperature of the ultrasound-assisted impregnation can be 20-35°C; the time can be 60-90 minutes, specifically 60 minutes, 70 minutes, 80 minutes or 90 minutes.

[0042] As an embodiment of the present application, after the ultrasonic-assisted impregnation, the carrier loaded with the active component and the eutectic solvent is further subjected to standing and drying. As an embodiment of the present application, the standing time can be 10-15 h, and specifically can be 10 h, 11 h, 12 h, 13 h, 14 h or 15 h. As an embodiment of the present application, the drying temperature can be 60-70℃, and the time can be 8-10 h.

[0043] The present application also provides the application of the eutectic solvent modified mercury-free catalyst in the acetylene hydrochlorination reaction.

[0044] The present application also provides a preparation method of vinyl chloride, comprising the following steps:

[0045] The catalyst is fixed in a fixed bed reactor, acetylene and hydrogen chloride are used as raw gas, and a catalytic reaction is performed to obtain vinyl chloride; the catalyst is the eutectic solvent modified mercury-free catalyst described in the above technical solution or the eutectic solvent modified mercury-free catalyst prepared by the preparation method described above;

[0046] As an embodiment of the present application, the space velocity of acetylene can be 50-80 h -1 , and specifically can be 50-300 h -1 ; the volume ratio of hydrogen chloride to acetylene in the raw gas can be 1.1-1.5:1; the reaction temperature of the catalytic reaction can be 130-180℃; and the reaction pressure can be normal pressure.

[0047] In order to further illustrate the present application, the schemes of the present application are described in detail below in combination with the drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0048] Example 1

[0049] 5g of coconut shell activated carbon is weighed, and the activated carbon is subjected to acid pickling treatment with 200mL of 3mol / L hydrochloric acid solution for 3h. After filtration, it is washed with deionized water until neutral, and dried at a temperature of 60℃ for 8h to obtain an activated carbon carrier.

[0050] Choline chloride (ChCl) and urea (Urea) (the molar ratio of choline chloride to urea is 1:2) are mixed, heated in a water bath at 80℃ for 5h to obtain a uniform transparent liquid, and then dried at 120℃ for 10h to obtain a eutectic solvent (DES).

[0051] A 0.5wt.% palladium chloride solution was added dropwise into 0.5g of the DES to obtain a DES-palladium mixed solution, and the mixed solution was added dropwise into the activated carbon carrier. After ultrasonic-assisted impregnation at 25°C for 80min, it was left to stand for 10h, and finally dried at a temperature of 65°C for 10h to obtain a DES modified mercury-free catalyst (denoted as 0.5Pd-10DES1 / CAC).

[0052] The DES modified mercury-free catalyst prepared in Example 1 was loaded into a fixed bed reactor, and the reaction conditions were: normal pressure, a reaction temperature of 160°C, a feed gas space velocity of 120h-1, and a feed gas ratio of V(HCl):V(C2H2) = 1.2. After the reaction was stabilized, samples were analyzed. After 10h of reaction, the acetylene conversion rate remained at 99.8%. -1

[0053] Example 2

[0054] 5g of coal-based activated carbon was weighed out, and the activated carbon was acid washed with 200mL of a 3mol / L hydrochloric acid solution for 3h. After filtration, it was washed to neutral with deionized water, and dried at a temperature of 60°C for 8h to obtain an activated carbon carrier. A certain amount of choline chloride and urea was weighed out, and the molar ratio was 1:2. The mixture was heated in a water bath at 80°C for 5h to obtain a uniform transparent liquid, and dried at 120°C for 10h to obtain a DES.

[0055] A 0.5wt.% palladium chloride solution was added dropwise into 0.75g of the DES to obtain a DES-palladium mixed solution, and the mixed solution was added dropwise into the activated carbon carrier. After ultrasonic-assisted impregnation at 25°C for 80min, it was left to stand for 12h, and finally dried at a temperature of 70°C for 8h to obtain a DES modified mercury-free catalyst (denoted as 0.5Pd-15DES / CAC).

[0056] The DES modified mercury-free catalyst prepared in Example 2 was loaded into a fixed bed reactor, and the reaction conditions were: normal pressure, a reaction temperature of 160°C, a feed gas space velocity of 120h-1, and a feed gas ratio of V(HCl):V(C2H2) = 1.2. After the reaction was stabilized, samples were analyzed. After 20h of reaction, the acetylene conversion rate remained at 99.8%. -1

[0057] Example 3

[0058] 5g of wood-based activated carbon was weighed out, and the activated carbon was acid washed with 200mL of a 3mol / L hydrochloric acid solution for 3h. After filtration, it was washed to neutral with deionized water, and dried at a temperature of 70°C for 8h to obtain an activated carbon carrier.

[0059] ​​Weigh a certain amount of choline chloride and N-methylformamide (NMF) in a molar ratio of 1:2. Heat at 80°C in a water bath for 5 hours to obtain a homogeneous transparent liquid. Dry at 120°C for 10 hours to obtain a deep eutectic solvent.

[0060] A 0.5 wt.% palladium chloride solution was added dropwise to 0.5 g of a deep eutectic solvent to produce a deep eutectic solvent-palladium mixed solution. This mixed solution was then added dropwise to an activated carbon support. Ultrasonic-assisted impregnation was performed at 25°C for 80 minutes, followed by 10 hours of undisturbed conditions. The mixture was then dried at 70°C for 10 hours to yield a deep eutectic solvent-modified mercury-free catalyst (denoted as 0.5Pd-10DES2 / CAC).

[0061] The mercury-free catalyst modified with the deep eutectic solvent prepared in Example 3 was loaded into a fixed bed reactor. The reaction conditions were: normal pressure, reaction temperature 160°C, feed gas space velocity 120h -1 The raw gas ratio was V(HCl):V(C2H2) = 1.2. After the reaction stabilized, samples were taken for analysis. After 10 hours of reaction, the acetylene conversion remained at 99.5%.

[0062] Example 4

[0063] Weigh 5g of coal-derived activated carbon and acid-wash it with 200mL of 3mol / L hydrochloric acid for 3 hours. Filter the mixture, wash it with deionized water until neutral, and dry it at 70°C for 8 hours to obtain the activated carbon support. Weigh a certain amount of choline chloride and benzamide in a molar ratio of 1:2. Heat the mixture in a water bath at 80°C for 5 hours to obtain a homogeneous, transparent liquid. Dry it at 120°C for 10 hours to obtain a deep eutectic solvent.

[0064] A 0.5 wt.% palladium chloride solution was added dropwise to 0.5 g of a deep eutectic solvent to produce a deep eutectic solvent-palladium mixed solution. This mixed solution was then added dropwise to an activated carbon support. Ultrasonic-assisted impregnation was performed at 25°C for 90 minutes, followed by 12 hours of undisturbed conditions. The mixture was then dried at 70°C for 8 hours to obtain a deep eutectic solvent-modified mercury-free catalyst (denoted as 0.5Pd-10DES3 / CAC).

[0065] The mercury-free catalyst modified with the deep eutectic solvent prepared in Example 4 was loaded into a fixed bed reactor. The reaction conditions were: normal pressure, reaction temperature 160°C, and feed gas space velocity 120h -1 The raw gas ratio was V(HCl):V(C2H2) = 1.2. After the reaction stabilized, samples were taken for analysis. After 10 hours of reaction, the acetylene conversion remained at 99.3%.

[0066] Example 5

[0067] Weigh 5g of coal-derived activated carbon and acid-wash it with 200mL of 3mol / L hydrochloric acid for 3 hours. Filter the mixture, wash it with deionized water until neutral, and dry it at 60°C for 10 hours to obtain the activated carbon support. Weigh a certain amount of choline chloride and acetamide in a molar ratio of 1:2. Heat the mixture in a water bath at 80°C for 5 hours to obtain a homogeneous, transparent liquid. Dry it at 120°C for 10 hours to obtain a deep eutectic solvent.

[0068] A 0.5 wt.% palladium chloride solution was added dropwise to 0.5 g of a deep eutectic solvent to produce a deep eutectic solvent-palladium mixed solution. This mixed solution was then added dropwise to an activated carbon support. Ultrasonic-assisted impregnation was performed at 25°C for 90 minutes, followed by 12 hours of undisturbed conditions. The mixture was then dried at 70°C for 10 hours to yield a deep eutectic solvent-modified mercury-free catalyst (denoted as 0.5Pd-10DES4 / CAC).

[0069] The mercury-free catalyst modified with the deep eutectic solvent prepared in Example 5 was loaded into a fixed bed reactor. The reaction conditions were: normal pressure, reaction temperature 160°C, feed gas space velocity 120h -1 The raw gas ratio was V(HCl):V(C2H2) = 1.2. After the reaction stabilized, samples were taken for analysis. After 10 hours of reaction, the acetylene conversion remained at 99%.

[0070] The infrared spectra of the deep eutectic solvent and its hydrogen bond donor and hydrogen bond acceptor obtained in Example 1 are shown in Figure 1 ,from Figure 1 It can be seen that: C=O(1685cm -1 ) and OH in ChCl (3244 cm -1 ) in the DES system are shifted and broadened, indicating the formation of intermolecular hydrogen bonds, that is, the formation of OH...O hydrogen bonds between -OH of ChCl and -C=O of Urea. -1 and 3446cm -1 ) also shifts and broadens in the DES system, but because it is close to the -OH stretching vibration peak, it forms a larger broad peak together. This is likely due to the NH…Cl hydrogen bond formed between the -NH2 of urea and the Cl- of ChCl. This proves the successful synthesis of DES.

[0071] Figure 2 The acetylene conversion rate-reaction time relationship diagram of the catalyst prepared in Examples 1, 3 to 5 is shown in FIG. Figure 2 It can be seen that the four deep eutectic solvent modified mercury-free catalysts all have good catalytic activity and stability, among which the acetylene conversion rate of 0.5Pd-10DES1 / CAC catalyst can be stabilized at 99.9%.

[0072] Figure 3The relationship between vinyl chloride selectivity and reaction time of the catalysts prepared in Examples 1, 3 to 5 is shown in FIG. Figure 3 It can be seen that the four deep eutectic solvent modified mercury-free catalysts all showed good vinyl chloride selectivity, which was maintained above 99%.

[0073] Figure 4 The acetylene conversion rate-reaction time relationship diagram of the catalyst prepared in Example 2 is shown in FIG. Figure 4 It can be seen that the 0.5Pd-15DES / CAC catalyst has high activity and high stability. The acetylene conversion rate remains above 90% within 3800 minutes.

[0074] Figure 5 The relationship between vinyl chloride selectivity and reaction time of the catalyst prepared in Example 2 is shown in FIG. Figure 5 It can be seen that the 0.5Pd-15DES / CAC catalyst exhibits a high vinyl chloride selectivity, which remains above 99% within 3800 min.

[0075] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A deep eutectic solvent modified mercury-free catalyst, characterized in that: It includes an activated carbon carrier, an active component located in the internal pores and on the surface of the activated carbon carrier, and a deep eutectic solvent; The active component is a metal halide and / or a metal complex; the metal element in the metal halide or metal complex is one or more of gold, palladium, platinum, ruthenium, rhodium, silver, copper and bismuth; The loading amount of the deep eutectic solvent in the deep eutectic solvent-modified mercury-free catalyst is 1 to 20 wt.%.

2. The deep eutectic solvent modified mercury-free catalyst according to claim 1, characterized in that: The activated carbon carrier is one or more of coconut shell activated carbon, wood activated carbon and coal activated carbon.

3. The deep eutectic solvent modified mercury-free catalyst according to claim 1, characterized in that: The hydrogen bond acceptor of the deep eutectic solvent is a quaternary ammonium ionic liquid and / or an imidazole ionic liquid; the hydrogen bond donor is one or more of urea, acetamide, N-methylformamide and benzamide.

4. The deep eutectic solvent modified mercury-free catalyst according to claim 3, characterized in that The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor in the deep eutectic solvent is 0.5 to 2.0:

1.

5. The deep eutectic solvent modified mercury-free catalyst according to claim 1, characterized in that: The active component loading amount in the deep eutectic solvent modified mercury-free catalyst is 0.1 to 20 wt.%.

6. The method for preparing the deep eutectic solvent-modified mercury-free catalyst according to claim 1, comprising the following steps: pre-treating the activated carbon to obtain an activated carbon carrier; mixing a hydrogen bond donor and a hydrogen bond acceptor and performing heat treatment to obtain a deep eutectic solvent; A mixed solution of the deep eutectic solvent and the active component is loaded onto an activated carbon carrier to obtain the deep eutectic solvent-modified mercury-free catalyst.

7. The preparation method according to claim 1, wherein The pretreatment comprises crushing and screening, pickling, filtering, washing with water and drying the activated carbon in sequence; the pickling reagent is a hydrochloric acid solution; the drying temperature is 60-70° C.; and the drying time is 8-10 hours.

8. The preparation method according to claim 1, wherein The heat treatment temperature is 70-90° C., and the heat treatment time is 5 hours. The loading method is ultrasound-assisted impregnation. The ultrasound-assisted impregnation temperature is 20-35° C., and the time is 60-90 minutes.

9. Use of the deep eutectic solvent-modified mercury-free catalyst according to claim 1 or the deep eutectic solvent-modified mercury-free catalyst prepared by the preparation method according to any one of claims 6 to 8 in acetylene hydrochlorination.

10. A method for preparing vinyl chloride, comprising the following steps: The catalyst is fixed in a fixed bed reactor, and acetylene and hydrogen chloride are used as raw materials to carry out a catalytic reaction to obtain vinyl chloride; the catalyst is the deep eutectic solvent-modified mercury-free catalyst according to claim 1 or the deep eutectic solvent-modified mercury-free catalyst prepared by the preparation method according to any one of claims 6 to 8.

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