Polyethylene nanofiber supported gold-ionic liquid catalyst for catalyzing hydrochlorination of acetylene and preparation and application thereof
By using a gold-ion liquid catalyst supported on polyethylene nanofibers in the acetylene hydrochlorination reaction, the problem of catalyst instability caused by reaction heat was solved, and efficient acetylene conversion and vinyl chloride selectivity were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH
- Filing Date
- 2023-12-26
- Publication Date
- 2026-06-05
Smart Images
Figure QLYQS_1 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to a polyethylene nanofiber supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene, its preparation and application. Background Technology
[0002] Vinyl chloride (VCM) is the monomer used in the industrial production of polyvinyl chloride (PVC). Large-scale production of vinyl chloride is widely referred to as the catalytic hydrochlorination of acetylene (C2H2). Nearly 40% of global vinyl chloride production capacity is produced via the calcium carbide process, using mercuric chloride (HgCl2) supported on activated carbon as a catalyst. However, these processes are not green because mercury is a volatile and toxic substance that harms human health and the environment. Furthermore, mercuric chloride is inevitably lost from the catalyst, limiting its lifespan. The rapid depletion of mercury deposits, coupled with the need to protect the environment and human health, urgently necessitates the development of a novel mercury-free acetylene hydrochlorination catalyst.
[0003] Ionic liquids, also known as room-temperature ionic liquids, room-temperature molten salts, or organic ionic liquids, are salts composed of organic cations and inorganic anions that are liquid below 100°C. Most ionic liquids are liquid at or near room temperature and exhibit a degree of stability in water. Due to the diversity of organic cations and inorganic anions, new ionic liquid materials with special functions can be designed and synthesized by changing their ratios, thus earning them the title of "solvents of the future."
[0004] Recently, interest has been rekindled in the search for commercially viable mercury-free catalysts for this important industrial process, with much of the research focusing on the use of gold as a catalyst.
[0005] CN 105148989 A discloses a porous solid material supported ionic liquid-gold catalyst, comprising a porous solid material support and a composite of an imidazole ionic liquid and a gold compound supported on the surface of the support. When used in the hydrochlorination reaction of acetylene, the acetylene conversion can reach 88.5%, and the selectivity for vinyl chloride is [not specified].
[0006] ≥99.9%. However, in the application of this catalyst in the acetylene hydrochlorination reaction, especially in the scale-up experiments in a fixed-bed reactor, the increased catalyst dosage generates a large amount of heat of reaction. This heat causes the temperature of the fixed-bed catalyst bed to rise rapidly, leading to the reduction and loss of high-valence Au, as well as carbonization, denaturation, and even loss of the ionic liquid. Therefore, the stability of this catalyst is poor.
[0007] Therefore, designing a new supported Au-ionic liquid catalyst for the acetylene hydrochlorination reaction, which can promptly remove the heat released by the reaction to protect the high valence state of the metal and prevent the denaturation or loss of the ionic liquid, is very promising. Summary of the Invention
[0008] The purpose of this invention is to provide a polyethylene nanofiber supported gold-ionic liquid catalyst for catalyzing the hydrochlorination of acetylene, its preparation and application, in order to solve the problems of high-valence Au being reduced and lost due to reaction heat and the carbonization, denaturation or even loss of the ionic liquid in the hydrochlorination of acetylene supported Au-ionic liquid catalyst system.
[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0010] In a first aspect, the present invention discloses a polyethylene nanofiber-supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene. The catalyst comprises a support and a gold active component and an ionic liquid supported on the support, wherein the support is polyethylene nanofiber.
[0011] Preferably, the polyethylene nanofibers are obtained by a preparation method comprising the following steps:
[0012] Step 1: Place the polymer blend containing 10-50 wt% polyethylene and 50-90 wt% paraffin oil in a container for pretreatment, controlling the pretreatment temperature at 80-100℃, and pour it into an extruder after forming a uniform gel.
[0013] Step 2: Using a twin-screw extruder, set the mold temperature to 180-220℃ and the casting roll temperature to 40-60℃, extrude the gel onto the cold rolling roll to obtain a uniform gel film; then cut the gel film into squares and stretch them bidirectionally along the side length direction, with a deformation rate of 2-5 mm / s in both directions, for 1-2 minutes.
[0014] Step 3: After stretching, place the sample in a stretching chamber and heat it at 100-110℃ for 3-5 minutes. Then cool it to room temperature. Finally, extract the sample with n-hexane and cut it into small pieces for later use.
[0015] In step one of this invention, the paraffin oil is used as a solvent and micropore forming agent, and its main component is an aliphatic hydrocarbon with a chain length of about 19 carbon atoms.
[0016] Preferably, in step two, the thickness of the prepared gel film is 0.6–0.8 mm.
[0017] In this invention, the gold active component and ionic liquid can be the gold active component and ionic liquid in the supported Au-ionic liquid system catalysts for the acetylene hydrochlorination reaction that have been reported previously.
[0018] Preferably, the ionic liquid is selected from at least one of the ionic liquids shown in the following structural formulas (1) to (4);
[0019]
[0020] In structural formula (1),
[0021] R1, R2, R3, and R4 are each independently represented by C. n H 2n+1 Or phenyl, where n is an integer and 1≤n≤16;
[0022] X - Selected from tetrafluoroborate, imine, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate;
[0023]
[0024] In structural formula (2),
[0025] R1, R2, R3, and R4 are each independently represented by C. n H 2n+1 Or C1-C4 alkoxy-substituted C n H 2n+1 n is an integer and 1 ≤ n ≤ 16;
[0026] X - Selected from tetrafluoroborate, imine, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate;
[0027]
[0028] In structural formula (3),
[0029] R1 is H, CH3, or C2H5;
[0030] R2 is C n H 2n+1 n is an integer and 1≤n≤6;
[0031] R3 is C k H 2k+1 k is an integer and 1≤k≤16;
[0032] X -Selected from tetrafluoroborate, imine, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate;
[0033]
[0034] In structural formula (4),
[0035] R1 and R2 are each independently defined as C. n H 2n+1 n is an integer and 1 ≤ n ≤ 16;
[0036] R3 represents H and C. n H 2n+1 Or O, where n is an integer and 1 ≤ n ≤ 16;
[0037] X - It is selected from tetrafluoroborate, imine, tetrachloroferrate, hexafluorophosphate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate.
[0038] As a further preferred option, the ionic liquid represented by formula (1) is selected from one of the following:
[0039] Tetrabutylphosphine tetrafluoroborate, tetrabutylphosphine tetrachloroferrate, trihexylhexadecylphosphine trifluoromethanesulfonate, tributylmethylphosphine p-toluenesulfonate, triphenylethylphosphine bis(trifluoromethanesulfonate) imine salt.
[0040] As a further preferred option, the ionic liquid represented by formula (2) is selected from one of the following:
[0041] N-Methoxyethyl-N-methyl-N,N-diethylammonium tetrafluoroborate, Trihexylmethylammonium bis(trifluoromethanesulfonic acid)imine salt, Tetraethylammonium p-toluenesulfonate.
[0042] As a further preferred option, the ionic liquid represented by formula (3) is selected from one of the following:
[0043] 1-Ethyl-2,3-dimethylimidazolium hexafluorophosphate, 1-Ethyl-2,3-dimethylimidazolium tetrafluoroborate, 1-Hexyl-3-methylimidazolium hexafluorophosphate, 1-Propyl-3-butylimidazolium tetrafluoroborate, 1-Methyl-3-hexadecylimidazolium bis(trifluoromethanesulfonate)imine salt, trimethylimidazolium tetrafluoroborate, 1-Methyl-3-octylimidazolium hexafluorophosphate.
[0044] As a further preferred option, the ionic liquid represented by formula (4) is selected from one of the following:
[0045] N-Butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, N-Butyl-N-methylpyrrolidine hexafluorophosphate.
[0046] The present invention particularly prefers that the ionic liquid be selected from one of the following:
[0047] Tetrabutylphosphine tetrafluoroborate; 1-hexyl-3-methylimidazolium hexafluorophosphate; 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate; triphenylethylphosphine bis(trifluoromethanesulfonyl)imide; N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide.
[0048] In this invention, the gold active component in the polyethylene nanofiber supported gold-ionic liquid catalyst can be a conventional gold active component and ionic liquid used in supported gold-ionic liquid catalysts for acetylene hydrochlorination. The loading amounts of the gold active component and ionic liquid are also conventional, for example, the loading amount of the gold active component (based on the mass ratio of gold element to support) is generally 1-5 wt%, and the loading amount of the ionic liquid (based on the mass ratio of ionic liquid to support) is generally 5-30 wt%.
[0049] Secondly, the present invention provides a method for preparing the polyethylene nanofiber-supported gold-ionic liquid catalyst, comprising the following steps:
[0050] Step 1: Dissolve the gold precursor in an acidic solution and sonicate for 5-10 minutes to prepare an Au solution;
[0051] Step 2: Add ionic liquid to Au solution, mix thoroughly, then add polyethylene nanofibers for impregnation treatment, and dry after thorough impregnation to obtain polyethylene nanofiber-supported gold-ionic liquid catalyst.
[0052] Preferably, in step 1, the gold precursor is chloroauric acid.
[0053] Preferably, in step 1, the acidic solution is concentrated hydrochloric acid, concentrated nitric acid, or aqua regia.
[0054] Preferably, in step 2, the immersion treatment conditions are: immersion in a fume hood at room temperature for 6-8 hours.
[0055] Preferably, in step 2, the drying conditions are: drying at 100-120℃ for 5-10 hours.
[0056] Thirdly, the present invention provides the application of the aforementioned polyethylene nanofiber-supported gold-ionic liquid catalyst in the catalytic hydrochlorination of acetylene to synthesize vinyl chloride.
[0057] The specific application is as follows: In a fixed-bed reactor, the polyethylene nanofiber-supported gold-ionic liquid catalyst is loaded, and the raw material gases HCl and C2H2 are introduced to react and obtain vinyl chloride.
[0058] Furthermore, the molar ratio of the raw material gases is n(HCl):n(C2H2) = 1:1 to 1.2:1, the reaction temperature is 120 to 200°C, and the acetylene volume hourly space velocity is 30 to 500 h⁻¹. -1 .
[0059] Compared with the prior art, the present invention has the following innovations and technical advantages:
[0060] (1) In this invention, polyethylene nanofibers were prepared by biaxial stretching and loaded with Au and ionic liquid, and the prepared polyethylene nanofiber-loaded gold-ionic liquid catalyst was applied to the catalytic hydrochlorination reaction of acetylene.
[0061] (2) The polyethylene nanofibers prepared by this invention solve the problems of high-valence Au being reduced and lost due to reaction heat and carbonization and even loss of ionic liquid catalysts in the acetylene hydrochlorination reaction, thus making them more stable.
[0062] (3) The reagents used in the method of the present invention are readily available, the process is simple, and it has a good application prospect. Detailed Implementation
[0063] The present invention will be illustrated below with specific embodiments. It should be noted that the embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention, which is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the invention.
[0064] The polyethylene used in this embodiment of the invention has a weight-average molecular weight (Mw) of 600,000 g / mol. Paraffin oil produced by Shangyu Zhengyuan Petrochemical Co., Ltd. was used.
[0065] Example 1
[0066] A method for preparing and applying a polyethylene nanofiber-supported Au ionic liquid catalyst for the hydrochlorination of acetylene includes the following steps:
[0067] 1) A polymer blend containing 30% polyethylene and 70% paraffin oil was pretreated in a custom-made mixing tank at 100°C to form a uniform gel before being fed into an extruder. Then, using a twin-screw extruder with a die temperature of 220°C and a casting roll temperature of 40°C, the gel was extruded onto a cold rolling roll to obtain a uniform gel film. A chiller unit was used to control the temperature of the cold rolling roll, ensuring temperature fluctuations were within ±1°C. The prepared film thickness was 0.6 mm. The gel film was then cut into 130 mm × 130 mm squares and stretched. After pneumatic clamping, biaxial stretching was performed using a biaxial stretcher. The deformation rate in both directions was 2 mm / s, and the stretching time was 1 min. After stretching, the samples were placed in a stretching chamber and heated at 100°C for 3 minutes, then cooled to room temperature. Finally, the samples were extracted with n-hexane and cut into small pieces for preservation.
[0068] 2) Dissolve the gold precursor HAuCl4·xH2O (containing 49wt% Au, the same below) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with an Au concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid tetrabutylphosphine tetrafluoroborate, mix thoroughly, and then add 10 g of the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation. After thorough impregnation, place it in a 120℃ oven and dry for 8 hours to obtain a catalyst with an ionic liquid loading of 10 wt% and an Au loading of 1 wt%, denoted as catalyst 1.
[0069] 3) Application of Catalyst 1 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 96.25%, and the vinyl chloride selectivity was 91.81%; after 1000 hours of reaction, the acetylene conversion rate was 87.26%, and the vinyl chloride selectivity was 89.04%.
[0070] Example 2: Effect of changing the proportion of polymer blends on the catalyst
[0071] 1) A polymer blend containing 50% polyethylene and 50% paraffin oil was pretreated in a custom-made mixing tank at 100°C to form a uniform gel before being fed into an extruder. Then, using a twin-screw extruder with a die temperature of 220°C and a casting roll temperature of 40°C, the gel was extruded onto a cold rolling roll to obtain a uniform gel film. A chiller unit was used to control the temperature of the cold rolling roll, ensuring temperature fluctuations were within ±1°C. The prepared film thickness was 0.6 mm. The gel film was then cut into 130 mm × 130 mm squares and stretched. After pneumatic clamping, biaxial stretching was performed using a biaxial stretcher. The deformation rate in both directions was 2 mm / s, and the stretching time was 1 min. After stretching, the samples were placed in a stretching chamber and heated at 100°C for 3 minutes, then cooled to room temperature. Finally, the samples were extracted with n-hexane and cut into small pieces for preservation.
[0072] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid tetrabutylphosphine tetrafluoroborate, mix thoroughly, and then add the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in a 120℃ oven for 8 hours to obtain a catalyst with an ionic liquid loading of 10wt% and an Au loading of 1wt%, denoted as catalyst 2.
[0073] 3) Application of Catalyst 2 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 96.05%, and the vinyl chloride selectivity was 92.18%; after 1000 hours of reaction, the acetylene conversion rate was 83.37%, and the vinyl chloride selectivity was 87.69%.
[0074] Example 3: Change the solution used for impregnation
[0075] 1) Prepare polyethylene nanofibers in the same manner as in Example 1;
[0076] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in 1mol / L hydrochloric acid solution and sonicate for 10 min to prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid tetrabutylphosphine tetrafluoroborate, mix thoroughly, and then add the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in a 120℃ oven for 8 hours to obtain a catalyst with an ionic liquid loading of 10wt% and an Au loading of 1wt%, denoted as catalyst 3.
[0077] 4) Application of Catalyst 3 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under conditions where n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 90.9%, and the vinyl chloride selectivity was 95.44%. After 1000 hours of reaction, the acetylene conversion rate was 85.22%, and the vinyl chloride selectivity was 85.16%.
[0078] Example 4
[0079] 1) Prepare polyethylene nanofibers in the same manner as in Example 1;
[0080] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid triphenylethylphosphine bis(trifluoromethanesulfonyl)imide salt, mix thoroughly, and then add the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in a 120℃ oven for 8 hours to obtain a catalyst with an ionic liquid loading of 10wt% and an Au loading of 1wt%, denoted as catalyst 4.
[0081] 4) Application of Catalyst 4 in the Hydrochlorination of Acetylene: The hydrochlorination of acetylene was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30 h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 81.42%, and the vinyl chloride selectivity was 95.61%. After 1000 hours of reaction, the acetylene conversion rate was 70.74%, and the vinyl chloride selectivity was 86.6%.
[0082] Example 5
[0083] 1) Prepare polyethylene nanofibers in the same manner as in Example 1;
[0084] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, mix thoroughly, and then add the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in a 120℃ oven for 8 hours to obtain a catalyst with an ionic liquid loading of 10wt% and an Au loading of 1wt%, which is designated as catalyst 5.
[0085] 4) Application of Catalyst 5 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 86.42%, and the vinyl chloride selectivity was 94.17%. After 1000 hours of reaction, the acetylene conversion rate was 76.74%, and the vinyl chloride selectivity was 86.6%.
[0086] Example 6
[0087] 1) Prepare polyethylene nanofibers in the same manner as in Example 1;
[0088] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid tetraethylammonium p-toluenesulfonate, mix thoroughly, and then add the prepared polyethylene nanofibers. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in an oven at 120℃ for 8 hours to obtain a catalyst with an ionic liquid loading of 10wt% and an Au loading of 1wt%, denoted as catalyst 6.
[0089] 4) Application of Catalyst 6 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 82.42%, and the vinyl chloride selectivity was 93.61%; after 1000 hours of reaction, the acetylene conversion rate was 72.74%, and the vinyl chloride selectivity was 85.86%.
[0090] Comparative Example 1: Polyethylene nanofibers as a catalyst
[0091] The reaction conditions were: temperature 150℃, acetylene space velocity 30 h⁻¹. -1 Under the condition that n(HCl):n(C2H2) = 1.1:1, polyethylene nanofibers prepared in the same steps as in Example 1 were cut into small pieces and used as catalyst 7 for the acetylene hydrochlorination reaction test. Initially, the acetylene conversion rate was 10.35%, and the vinyl chloride selectivity was 70.23%; after 1000 hours of reaction, the acetylene conversion rate was 5.23%, and the vinyl chloride selectivity was 50.39%.
[0092] Comparative Example 2: Carbon nanotubes as a carrier
[0093] 1) Take 20g of carbon nanotubes with a diameter of about 20nm, soak them in 50mL of 0.1mol / L hydrochloric acid solution for 10min, rinse them with deionized water several times until neutral, and put them in an oven at 120℃ for 6h.
[0094] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, add 1 g of the ionic liquid tetrabutylphosphine tetrafluoroborate, mix thoroughly, and then add 10 g of the treated carbon nanotubes. Place the mixture in a fume hood at room temperature for 6 hours of impregnation, and after thorough impregnation, place it in a 120℃ oven for 8 hours to obtain a catalyst with an ionic liquid loading of 10 wt% and an Au loading of 1 wt%, which is designated as catalyst 8.
[0095] 4) Application of Catalyst 8 in the Hydrochlorination of Acetylene: The hydrochlorination of acetylene was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30 h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 90.42%, and the vinyl chloride selectivity was 95.61%. After 1000 hours of reaction, the acetylene conversion rate was 70.74%, and the vinyl chloride selectivity was 86.6%.
[0096] Comparative Example 3: Unloaded Ionic Liquid
[0097] 1) A polymer blend containing 30% polyethylene and 70% paraffin oil was pretreated in a custom-made mixing tank at 100°C to form a uniform gel before being fed into an extruder. Then, using a twin-screw extruder with a die temperature of 220°C and a casting roll temperature of 40°C, the gel was extruded onto a cold rolling roll to obtain a uniform gel film. A chiller unit was used to control the temperature of the cold rolling roll, ensuring temperature fluctuations were within ±1°C. The prepared film thickness was 0.6 mm. The gel film was then cut into 130 mm × 130 mm squares and stretched. After pneumatic clamping, biaxial stretching was performed using a biaxial stretcher. The deformation rate in both directions was 2 mm / s. After stretching, the samples were placed in a stretching chamber and heated at 100°C for 3 minutes, then cooled to room temperature. Finally, the samples were extracted with n-hexane and cut into small pieces for preservation.
[0098] 2) Dissolve the gold precursor HAuCl4·xH2O (49wt%) in aqua regia (3:1 HCl (32wt%): HNO3 (70wt%)), sonicate for 10 min, and prepare an Au solution with a concentration of 0.01 g / mL. Take 10 mL of the prepared Au solution, mix thoroughly, add the prepared polyethylene nanofibers, and impregnate in a fume hood at room temperature for 6 hours. After thorough impregnation, place in a 120℃ oven and bake for 8 hours to obtain a catalyst with an Au loading of 1wt%, designated as catalyst 9.
[0099] 3) Application of Catalyst 9 in the acetylene hydrochlorination reaction: The acetylene hydrochlorination reaction was evaluated in a fixed-bed reactor under the following conditions: temperature 150℃, acetylene space velocity 30h⁻¹. -1 The reaction was carried out under the condition that n(HCl):n(C2H2) = 1.1:1. Initially, the acetylene conversion rate was 76.25%, and the vinyl chloride selectivity was 90.81%; after 1000 hours of reaction, the acetylene conversion rate was 67.26%, and the vinyl chloride selectivity was 89.04%.
Claims
1. A polyethylene nanofiber-supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene, the catalyst comprising a support and a gold active component and an ionic liquid supported on the support, characterized in that: The carrier is polyethylene nanofiber; The polyethylene nanofibers are obtained by a preparation method comprising the following steps: Step 1: Place the polymer blend containing 10~50wt% polyethylene and 50~90wt% paraffin oil in a container for pretreatment, control the pretreatment temperature at 80~100℃, and pour it into the extruder after forming a uniform gel. Step 2: Using a twin-screw extruder, set the mold temperature to 180~220℃ and the casting roll temperature to 40~60℃, extrude the gel onto the cold rolling roll to obtain a uniform gel film; then cut the gel film into squares and stretch them bidirectionally along the side length direction, with a deformation rate of 2~5mm / s in both directions, for 1~2min. Step 3: After stretching, place the sample in a stretching chamber and heat it at 100~110℃ for 3~5 minutes. Then cool it to room temperature. Finally, extract the sample with n-hexane and cut it into small pieces for later use.
2. The polyethylene nanofiber-supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene as described in claim 1, characterized in that: In step two, the thickness of the prepared gel membrane is 0.6~0.8 mm.
3. The polyethylene nanofiber-supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene as described in claim 1 or 2, characterized in that: The ionic liquid is selected from at least one of the ionic liquids shown in the following structural formulas (1) to (4); In structural formula (1), R1, R2, R3, and R4 are each independently represented by C. n H 2n+1 Or phenyl, where n is an integer and 1≤n≤16; X - Selected from tetrafluoroborate, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate; In structural formula (2), R1, R2, R3, and R4 are each independently represented by C. n H 2n+1 Or C1-C4 alkoxy-substituted C n H 2n+1 n is an integer and 1 ≤ n ≤ 16; X - Selected from tetrafluoroborate, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate; In structural formula (3), R1 is H, CH3, or C2H5; R2 is C n H 2n+1 n is an integer and 1≤n≤6; R3 is C k H 2k+1 k is an integer and 1≤k≤16; X - Selected from tetrafluoroborate, tetrachloroferrate, trifluoromethanesulfonate, bis(trifluoromethanesulfonate)imine, p-toluenesulfonate or p-isobutylphenylpropionate; In structural formula (4), R1 and R2 are each independently defined as C. n H 2n+1 n is an integer and 1 ≤ n ≤ 16; R3 represents H and C. n H 2n+1 Or O, where n is an integer and 1 ≤ n ≤ 16; X - It is selected from tetrafluoroborate, tetrachloroferrate, hexafluorophosphate, bis(trifluoromethanesulfonate)imide, p-toluenesulfonate or p-isobutylphenylpropionate.
4. The polyethylene nanofiber-supported gold-ionic liquid catalyst for catalyzing the hydrochlorination reaction of acetylene as described in claim 3, characterized in that: The ionic liquid represented by formula (1) is selected from one of the following: Tetrabutylphosphine tetrafluoroborate, tetrabutylphosphine tetrachloroferrate, trihexylhexadecylphosphine trifluoromethanesulfonate, tributylmethylphosphine p-toluenesulfonate, triphenylethylphosphine bis(trifluoromethanesulfonate) imine salt; The ionic liquid represented by formula (2) is selected from one of the following: N-Methoxyethyl-N-methyl-N,N-diethylammonium tetrafluoroborate, Trihexylmethylammonium bis(trifluoromethanesulfonic acid)imine salt, Tetraethylammonium p-toluenesulfonate; The ionic liquid represented by formula (3) is selected from one of the following: 1-Ethyl-2,3-dimethylimidazolium tetrafluoroborate, 1-propyl-3-butylimidazolium tetrafluoroborate, 1-methyl-3-hexadecylimidazolium bis(trifluoromethanesulfonate)imine salt, trimethylimidazolium tetrafluoroborate; The ionic liquid represented by formula (4) is selected from one of the following: N-Butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, N-Butyl-N-methylpyrrolidine hexafluorophosphate.
5. A method for preparing a polyethylene nanofiber-supported gold-ionic liquid catalyst as described in any one of claims 1-4, characterized in that: The preparation method includes the following steps: Step 1: Dissolve the gold precursor in an acidic solution and sonicate for 5-10 minutes to prepare an Au solution; Step 2: Add ionic liquid to Au solution, mix thoroughly, then add polyethylene nanofibers for impregnation treatment, and dry after thorough impregnation to obtain polyethylene nanofiber-supported gold-ionic liquid catalyst.
6. The preparation method according to claim 5, characterized in that: In step 1, the acidic solution is concentrated hydrochloric acid, concentrated nitric acid, or aqua regia.
7. The preparation method according to claim 5, characterized in that: In step 2, the immersion treatment conditions are: immersion in a fume hood at room temperature for 6-8 hours.
8. The preparation method according to claim 5, characterized in that: In step 2, the drying conditions are: drying at 100~120℃ for 5~10 hours.
9. The application of the polyethylene nanofiber-supported gold-ionic liquid catalyst as described in any one of claims 1-4 in the reaction of catalytic hydrochlorination of acetylene to synthesize vinyl chloride.