Gold-containing catalysts, methods of making and uses

Abstract

The present specification describes a process for producing a hydrochlorination catalyst, the process comprising the steps of: i) preparing an impregnation solution by combining a source of gold and a ligand in a solvent, wherein the solvent comprises an organic solvent; ii) impregnating a support with the impregnation solution from step (i); and iii) drying the product of step (ii) to obtain a catalyst. Also described is a hydrochlorination catalyst comprising a complex of gold and a ligand of formula (I) supported on a support. These catalysts are particularly suitable for use in the conversion of acetylene to vinyl chloride monomer.

Description

Technical Field

[0001] This invention relates to gold-containing catalysts, particularly gold-containing catalysts for the conversion of acetylene into vinyl chloride monomer (VCM). Background Technology

[0002] The hydrochlorination of acetylene to produce VCM as a precursor for polyvinyl chloride (PVC) is currently a large-scale industrial method, particularly in coal-rich regions such as China and in gas-rich areas via the natural gas-to-acetylene route. Over 20 million tons of VCM are produced annually via acetylene hydrochlorination, the vast majority of which utilizes mercuric chloride (HgCl2) catalysts supported on activated carbon. Due to the sublimation of volatile HgCl2 from the catalyst bed, up to 0.6 kg Hg / ton of VCM production, the mercury catalyst poses significant environmental problems. Because of the environmental impact of this process, the recently ratified Minamata Convention mandates that all new VCM plants must use mercury-free catalysts, and in the near future, all existing industrial plants must convert to mercury-free alternatives. This has revived commercial interest in using gold and other metals as catalysts for this reaction.

[0003] According to WO2010 / 055341 (Johnson Matthey PLC and Aker Process BV), Au-containing catalysts prepared by wet impregnation of a mixture of HAuCl4 / aqua regia are active for the conversion of acetylene to VCM. The catalysts are believed to contain gold particles with a metallic gold core and a shell of higher oxidation state substances, including Au(I) and Au(III), which are considered active substances in the hydrochlorination reaction.

[0004] WO2013 / 008004 (Johnson & Co.) describes the development of HAuCl4-based catalysts by incorporating sulfur-containing ligands such as thiosulfates. It is believed that the sulfur-containing ligands form complexes with Au atoms, thereby stabilizing Au(I) and Au(III) as the active substances in the hydrochlorination reaction.

[0005] Further development of the above catalysts is described in WO2020 / 254817 (Johnson & Johnson), which includes inorganic oxides, hydroxides, oxyacids or oxysalts to improve the catalyst’s resistance to carbon nanotube formation.

[0006] VCM catalysts containing gold-thiosulfate ligand complexes on carbon supports have been developed by Johnson Matthey under the trademark PRICAT. TMCommercialization of MFCs. While these catalysts have achieved commercial success, their very high initial activity in the extremely exothermic hydrochlorination of acetylene requires careful optimization for specific systems. If the catalyst activity is initially too high, localized hot spots may form in the catalyst bed, potentially leading to deactivation. Alternative catalysts with more stable activity characteristics and less susceptibility to initial overheating are needed. This invention addresses this problem. Summary of the Invention

[0007] The inventors have discovered that catalysts with stable activity characteristics and less susceptibility to initial overheating can be prepared by modifying the production methods described in WO2013 / 008004 and WO2020 / 254817. The methods exemplified in these references involve forming an aqueous impregnation solution containing a complex of gold and sulfur-containing ligands, which is then applied to a carbon support. The inventors have surprisingly discovered that the initial activity of the catalyst can be reduced by replacing the aqueous solvent of the impregnation solution with an organic solvent or a mixture of an organic solvent and an aqueous solvent. Without being bound by theory, it is believed that this change alters the wetting between the catalyst and the impregnation solution, which in turn alters the dispersion of the gold complex on the support.

[0008] In a first aspect, the present invention relates to a method for manufacturing a hydrochlorination reaction catalyst, the method comprising the following steps:

[0009] i) Prepare an impregnation solution by incorporating the gold source and ligand in a solvent, wherein the solvent includes an organic solvent;

[0010] ii) Impregnate the carrier with the impregnation solution from step (i); and

[0011] iii) Dry the product of step (ii) to obtain the catalyst.

[0012] WO2020 / 016555 (University College Cardiff Consultants Ltd) describes a method for producing a catalyst for hydrochlorination reactions, which involves combining gold, an organic solvent, and a support material. In the embodiments of this reference, the catalyst is prepared by impregnating a solution of HAuCl4·3H2O in an organic solvent. An advantage of this method is that it does not require a ligand. The method according to the first aspect is similar to that in WO2020 / 016555, but requires impregnation with an impregnation solution containing a ligand in addition to the gold source.

[0013] The method according to the first aspect can be used to prepare complexes similar to those described in WO2013 / 008004 and WO2020 / 254817, i.e., in which the ligand is sulfur-containing. However, other advantages in terms of stability can be achieved by replacing the sulfur-containing ligand with a ligand of formula (I) as described herein.

[0014] In a second aspect, the present invention relates to a catalyst comprising a complex of gold and a ligand of formula (I).

[0015]

[0016] in

[0017] X is O or S;

[0018] n is 1 or 2;

[0019] R is H or optionally contains one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen, or nitrogen, and C1 to C10 hydrocarbon groups;

[0020] The complex is loaded onto a carrier.

[0021] It is not yet fully understood that catalysts containing gold and formula I ligands are coordination complexes (e.g., formula Au[ligand]). 4-x Cl x The complex can be an adduct (where x = 1 to 4) or an adduct (e.g., [AuCl3] ligand). This can vary depending on the choice of ligand. As used herein, the term "complex" encompasses both possibilities. To avoid ambiguity, the oxidation state of Au within the complex can be +1 or +3.

[0022] Copper and nitrogen-containing ligand complexes are known to be used as catalysts in the conversion of acetylene to VCM. CN111774094A and CN111715253A (Nankai University) describe a method for producing a copper-based catalyst for the production of vinyl chloride. This method involves impregnating a carbon support with an impregnation solution containing copper chloride and various additives, which may be nitrogen-containing ligands. CN110743624A (Zhejiang University of Technology) describes a comparative example prepared by combining a solution of CuCl2·2H2O and N-methylpyrrolidone (NMP) with activated carbon, followed by drying and treatment with hydrogen chloride gas. To the knowledge of the inventors, similar complexes of gold and NMP have not been previously described.

[0023] In a third aspect, the present invention relates to a method for catalytically hydrochlorinizing a substrate containing an alkyne unit, wherein the reaction is carried out in the presence of a catalyst according to the second aspect or a catalyst produced or producible by the method according to the first aspect.

[0024] This method is particularly suitable when acetylene is used as a substrate to produce VCM. The conversion of acetylene to VCM is preferably carried out in the gas phase. Attached Figure Description

[0025] Figure 1 The activity of catalysts E1 to E11 over time is shown.

[0026] Figure 2 The activity of catalysts E2-1.2, E2-2.0 and E2-4.0 over time is shown.

[0027] Figure 3 The NMR spectra of NMP and the complex formed by combining HAuCl4·3H2O and NMP in a 1:4 molar ratio are shown.

[0028] Figure 4 The activity of catalyst E2-1.2 at different temperatures is shown.

[0029] Figure 5 The activity of catalysts E12 to E18 over time is shown.

[0030] Figure 6 The activity of catalysts E19 (comparison) and E20 over time is shown.

[0031] Figure 7 The activity of catalysts E21 and E22 over time is shown.

[0032] Figure 8 The single-crystal X-ray structure of [HAuCl4](NMP)2 is shown. Detailed Implementation

[0033] Unless otherwise specified, all percentages in this document refer to percentages based on the weight of the total catalyst.

[0034] Catalyst manufacturing

[0035] According to a first aspect of the present invention, a method for manufacturing a hydrochlorination reaction catalyst is provided, the method comprising the following steps:

[0036] i) Prepare an impregnation solution by incorporating the gold source and ligand in a solvent, wherein the solvent includes an organic solvent;

[0037] ii) Impregnate the carrier with the impregnation solution from step (i); and

[0038] iii) Dry the product of step (ii) to obtain the catalyst.

[0039] It is assumed that in step (i), a complex is formed between the gold and the ligand. Preferably, the impregnation solution is prepared by adding the ligand to a solution containing a gold source and a solvent. However, the gold source can also be added to a solution containing the ligand and a solvent. It is also anticipated that the catalyst can be prepared by treating the support with the gold source followed by the ligand, or vice versa.

[0040] The gold source is typically a gold salt capable of forming a complex with the ligand. A preferred gold source is HAuCl4, in solid form (e.g., HAuCl4·3H2O) or in solution form (e.g., a solution of HAuCl4 in HCl / water).

[0041] Solvents include organic solvents. It is believed that the presence of organic solvents in the impregnation solution alters the wetting between the impregnation solution and the carrier, thereby resulting in improved gold dispersion compared to when an aqueous solution of a gold complex is used as the impregnation solution.

[0042] In some embodiments, the solvent is an organic solvent. This may be preferred when both the gold source and the ligand are soluble in an organic solvent.

[0043] In some embodiments, the solvent includes a mixture of organic and aqueous solvents. This may be necessary when either the gold source or the ligand has poor solubility in the organic solvent. For example, if the gold source is soluble in the organic solvent but the ligand is poorly soluble, the ligand can be dissolved in an aqueous solvent and then added to the solution of the gold in the organic solvent.

[0044] Suitable organic solvents are described in WO2020 / 016555, the contents of which are incorporated herein by reference.

[0045] In some embodiments, the preferred organic solvent is E. T (30) Polarity ≤62, e.g. ≤60, ≤55, or ≤50. E is measured by the method described in C. Reichardt, *Angewandte Chemie International Edition*, 1979, 18, pp. 98-110. T (30) Polarity. When the solvent includes a mixture of organic solvents, or a mixture of organic solvents and water, E T (30) Polarity refers to the entire solvent.

[0046] In some embodiments, it is preferred that the organic solvent has a boiling point of ≤120°C, for example ≤100°C or ≤90°C at 1 atm.

[0047] The organic solvent is preferably selected from the group consisting of alcohols, ketones, esters, ethers, sulfoxides, nitriles, amides, or mixtures thereof.

[0048] Preferred alcohol solvents are methanol, ethanol, propanol, and butanol.

[0049] Preferred ketone solvents are acetone, butanone, and cyclohexanone. Acetone is a particularly preferred solvent.

[0050] The preferred ester solvent is ethyl acetate.

[0051] Preferred ether solvents are diethyl ether and tetrahydrofuran.

[0052] The preferred sulfoxide solvent is dimethyl sulfoxide.

[0053] The preferred amide solvent is dimethylformamide.

[0054] In some embodiments, the ligand is a sulfur-containing ligand. Suitable ligands are described in WO2013 / 008004, the contents of which are incorporated herein by reference. When the ligand is sulfur-containing, it is preferred that the ligand be selected from sulfonates, thiosulfates, thiocyanates, thioureas, or thiols. Preferred ligands include thiosulfates, thiocyanates, thiopropionic acid, and thiomalic acid. Thiosulfates are particularly preferred ligands.

[0055] In an alternative embodiment, the ligand has the following formula (I) as defined below with respect to the catalyst.

[0056] The molar equivalent of the added formula (I) ligand relative to gold is preferably 1:1 to 1:4, for example, 1:1 to 1:2. Containing more than 4 molar equivalents of ligand does not appear to impair catalyst performance, but is disadvantageous in terms of cost. Using 1.2 molar equivalents of ligand is generally sufficient to achieve complete gold complexation.

[0057] In step (ii), the carrier is impregnated with the impregnation solution formed in step (i). Impregnation techniques are well known to those skilled in the art.

[0058] In step (iii), the catalyst is dried to remove the organic solvent. Drying techniques are well known to those skilled in the art. Typical methods involve heating the catalyst at a temperature ≥100°C for a period of 12 hours or longer. A gas stream can be used to aid in the removal of the organic solvent. It should be understood that the drying temperature and duration will vary depending on the scale of the preparation being carried out.

[0059] catalyst

[0060] The present invention also relates to catalysts comprising complexes of gold and formula (I) ligands.

[0061]

[0062] in

[0063] X is O or S;

[0064] n is 1 or 2;

[0065] R is H or optionally contains one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen, or nitrogen, and C1 to C10 hydrocarbon groups;

[0066] The complex is loaded onto a carrier.

[0067] Preferably, X is O. Compared to when X is O, using ligands where X is S tends to have lower activity.

[0068] In one embodiment, R is a C1 to C10 hydrocarbon group, such as a C1 to C6 hydrocarbon group, containing one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen (e.g., OH), or nitrogen (e.g., NH2). For example, a C1-C6 hydrocarbon group or a C1-C3 hydrocarbon group, in each case containing one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen (e.g., OH), or nitrogen (e.g., NH2). The presence of heteroatoms in group R can improve the solubility of the ligand in highly polar solvents.

[0069] In one embodiment, R is a C1-C10 hydrocarbon group consisting only of C and H atoms, such as a C1-C6 hydrocarbon group. For example, a C1-C6 hydrocarbon group or a C1-C3 hydrocarbon group. The absence of heteroatoms in group R can improve the solubility of the ligand in low-polarity solvents.

[0070] Preferably, R is H or Me, and more preferably R is Me. Using a ligand where R is H tends to result in lower activity compared to when R is Me.

[0071] Preferably, n is 1.

[0072] Preferred ligands are N-methyl-2-pyrrolidone (NMP) and N-methyl-2-piperidinone. These ligands exhibit acetylene conversion comparable to or better than that of comparative catalysts containing gold thiosulfate complexes. NMP is a particularly preferred ligand.

[0073] To avoid any questions, NMP has the following structure:

[0074]

[0075] The role of the ligand is to stabilize Au in its Au(I) or Au(III) oxidation state. The method of this invention enables the production of catalysts with high Au dispersibility and high proportions of Au(I) and Au(III) substances, which are considered to be active substances for hydrochlorination reactions.

[0076] The Au loading is a trade-off between the cost of Au and the activity of the catalyst. Typical Au content in a catalyst is generally from 0.01 wt% to 5 wt% based on the total weight of the catalyst. Typically, Au loading is from 0.01 wt% to 2 wt%, for example from 0.05 wt% to 1.5 wt%, for example from 0.2 wt% to 1.5 wt%.

[0077] In some embodiments, in addition to Au, the catalyst may also contain one or more promoter metals. The presence of promoter metals can improve the activity of the catalyst and / or help maintain the activity of the catalyst over time. Suitable promoters include Group 1 and Group 2 metals, as well as cobalt, copper, lanthanum, and cerium.

[0078] The catalyst of the present invention can be prepared using any known catalyst support. Typical metal oxide supports, such as alumina, silica, zeolite, silica-alumina, titanium dioxide, or zirconium oxide, and their composites, can be used. Preferably, the support is a carbon support. The carbon can be derived from natural sources (e.g., peat, wood, coal, graphite) or can be synthetic carbon. The carbon is preferably activated carbon, such as activated carbon activated by steam, acid, or other chemical methods.

[0079] The carrier can be in the form of powder, granules, or shaped particles. Examples of shaped particles include spheres, tablets, cylinders, multi-lobed cylinders (e.g., trefoil), rings, miniliths, or bulk catalyst units such as bulk materials. Alternatively, the catalyst in powder form can be contained in a coating formulation and coated onto the reactor wall or a shaped substrate such as a bulk material. A preferred form of catalyst carrier includes multiple shaped units in the form of cylinders, spheres, or lobed cylinders, each cylinder, sphere, or lobed cylinder having a diameter of 0.1 mm to 10 mm, or more preferably a diameter in the range of 1 mm to 3 mm. In cases with a non-uniform diameter cross-sectional shape, such as a lobed cylinder, the diameter is the average diameter. Cylinders and trefoil shapes are particularly preferred carrier shapes.

[0080] Applications of catalysts

[0081] It is envisioned that the catalyst of the present invention can be used in any chemical process in which gold-containing catalysts are known to be practical. This catalyst is particularly suitable for the hydrochlorination of compounds containing an alkyne moiety, especially for the conversion of acetylene to VCM.

[0082] The conversion of acetylene to VCM typically occurs at elevated temperatures, usually between approximately 100°C and 250°C. The reaction temperature represents a balance between conversion and economics when operating the reactor at higher temperatures. Furthermore, coking can become significant at temperatures substantially above 200°C. Surprisingly, catalysts containing the (I) ligand exhibit activity at lower temperatures than existing Au-based catalysts.

[0083] Premixing HCl and acetylene is preferred, and preheating to the reaction temperature is also preferred. Typically, the amount of HCl present exceeds the amount required for the stoichiometric reaction. The catalyst may be present in the reactor as a fixed bed of catalyst particles arranged such that the feed gas passes through or through the catalyst bed. Alternative reactor arrangements, including fluidized bed or other moving bed arrangements, may be used. Alternatively, the catalyst may be provided in bulk form or coated onto the walls of the reaction vessel. If desired, the catalyst bed may have temperature control devices to prevent overheating due to the exothermic reaction or to avoid temperature increases. It may be preferred to treat the catalyst with HCl prior to use in this method. This treatment is typically carried out by flowing HCl over the catalyst at a temperature of at least 50°C, more particularly >100°C, for a period of at least one hour. This pretreatment can be carried out in the reactor by operating with HCl in the absence of acetylene at a suitable temperature.

[0084] The present invention includes the following embodiments.

[0085] 1. A method for producing a catalyst for a hydrochlorination reaction, the method comprising the following steps:

[0086] i) An impregnation solution is prepared by incorporating a gold source and a ligand in a solvent, wherein the solvent includes an organic solvent;

[0087] ii) Impregnate the carrier with the impregnation solution from step (i);

[0088] iii) Dry the product of step (ii) to obtain the catalyst.

[0089] 2. The method according to embodiment 1, wherein the solvent is composed of the organic solvent.

[0090] 3. The method according to embodiment 1, wherein the solvent is composed of a mixture of an organic solvent and an aqueous solvent.

[0091] 4. The method according to any one of embodiments 1 to 3, wherein the support is a carbon support.

[0092] 5. The method according to any one of embodiments 1 to 4, wherein the organic solvent is selected from the group consisting of alcohols, ketones, esters, ethers, sulfoxides, nitriles, amides, or mixtures thereof.

[0093] 6. The method according to any one of embodiments 1 to 5, wherein the organic solvent comprises or is composed of acetone.

[0094] 7. The method according to any one of embodiments 1 to 6, wherein the ligand is a sulfur-containing ligand.

[0095] 8. The method according to embodiment 7, wherein the sulfur-containing ligand is selected from the group consisting of sulfonates, thiosulfates, thiocyanates, thioureas, or thiols.

[0096] 9. The method according to embodiment 7, wherein the sulfur-containing ligand is a thiosulfate.

[0097] 10. The method according to any one of embodiments 1 to 6, wherein the ligand has formula (I)

[0098]

[0099] in

[0100] X is O or S;

[0101] n is 1 or 2;

[0102] R is H or optionally contains one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen, or nitrogen, and is a C1 to C10 hydrocarbon group.

[0103] 11. The method according to implementation scheme 10, wherein X is O.

[0104] 12. The method according to claim 10 or claim 11, wherein R is Me.

[0105] 13. The method according to embodiment 10, wherein the ligand is N-methyl-2-pyrrolidone.

[0106] 14. The method according to any one of embodiments 10 to 13, wherein the molar ratio of Au:ligand in step (i) is 1:1 to 1:2.

[0107] 15. A hydrochlorination reaction catalyst comprising a complex of a gold and a ligand of formula (I).

[0108]

[0109] in

[0110] X is O or S;

[0111] n is 1 or 2;

[0112] R is H or optionally contains one or more heteroatoms selected from halogens (F, Cl, Br, I), oxygen, or nitrogen, and is a C1 to C10 hydrocarbon group; and

[0113] The complex is loaded onto a carrier.

[0114] 16. The catalyst according to embodiment 15, wherein X is O.

[0115] 17. The catalyst according to claim 15 or claim 16, wherein R is H.

[0116] 18. The catalyst according to claim 15 or claim 16, wherein R is Me.

[0117] 19. The catalyst according to embodiment 15, wherein the ligand is N-methyl-2-pyrrolidone.

[0118] 20. The catalyst according to any one of embodiments 15 to 19, wherein the molar ratio of Au:ligand is 1:1 to 1:4.

[0119] 21. The catalyst according to any one of embodiments 15 to 20, wherein the Au content in the catalyst is from 0.01% to 5% by weight.

[0120] 22. The catalyst according to any one of embodiments 15 to 21, wherein the support is in the form of powder, granules or shaped particles.

[0121] 23. The catalyst according to any one of embodiments 15 to 22, wherein the support is a carbon support.

[0122] 24. A method for catalytically hydrochlorinizing a substrate containing an alkyne unit, wherein the reaction is carried out in the presence of a catalyst according to any one of embodiments 15 to 23 or a catalyst that can be produced by the method according to any one of embodiments 1 to 14.

[0123] 25. The method according to embodiment 24, wherein the substrate is acetylene.

[0124] Example

[0125] General procedures for catalyst testing

[0126] The catalyst sample (approximately 90 mg) was loaded onto glass wool inside the reactor tube. The feed stream was prepared by combining 24.00 mL / min C₂H₂ (5% acetylene in argon), 30.00 mL / min HCl (5% HCl in argon), and 4.10 mL / min argon. Unless otherwise specified, the feed stream temperature was set to 180 °C. Acetylene conversion was determined by gas chromatography.

[0127] Example 1 - Preparation of a ligand-free comparative catalyst (E1)

[0128] Catalyst E1 was prepared by impregnation. First, activated carbon (NORIT ROX 0.8) was ground and sieved (150 mesh) to obtain a powder with a particle size <150 μm. The gold precursor HAuCl4·3H2O (solid from Alfa Aesar, 20 mg, 49% determined) was dissolved in anhydrous acetone (2.7 mL) and stirred for 10 minutes. The solution was then added dropwise to the ground, activated, dried carbon powder (0.99 g) with stirring. The solution was stirred at room temperature for 1 hour and finally dried at 45 °C under nitrogen for 16 hours.

[0129] Examples 2 to 11 - Role of Ligands

[0130] Examples 2 to 11 reported in Table 1 were prepared by the same method as described in Example 1, with the following modifications. The ligands were weighed into vials. A solution of HAuCl4·3H2O in acetone was added to the ligands, and the resulting solution was used to impregnate carbon powder as described in Example 1. The Au:ligand (mol:mol) ratio was 1:1.2, 1:2, or 1:4. The final Au loading was 1% by weight.

[0131]

[0132] Table 1 .

[0133] The acetylene conversion of these catalysts was tested following standard procedures. The results are shown in... Figure 1 In the test, all catalysts except E1 (ligand-free), E2-1.2 (NMP), and E10 (benzyl isothiocyanate) were deactivated during the test.

[0134] The role of ligand equivalents

[0135] exist Figure 2 The effects of ligand equivalents of E2-1.2, E2-2.0, and E2-4.0 were compared. Their performance was similar, but generally E2-4.0 > E2-2.0 > E2-1.2.

[0136] NMP in d6-acetone and E2-4.0 prepared in d6-acetone 1 The coverage diagram of the H NMR spectrum is from Figure 3 In the complex, all peaks associated with NMP shift, indicating that NMP is coordinated.

[0137] The effect of temperature

[0138] The activity of Example E2-1.2 was tested at temperatures of 30°C, 65°C, 120°C, 180°C, 200°C, and 220°C. The results are shown in... Figure 4 The activity increases with increasing temperature. Although the acetylene conversion rate is highest at 220℃, the amount of acetylene converted does not correspond to the amount of VCM produced. This difference is believed to be related to coke formation at high temperatures.

[0139] Examples 12 to 18 - Alternative Ligands

[0140] The catalysts in Table 2 were prepared using 1.2 equivalents of ligand, following the same procedures as in Examples 2-11. The final Au loading was 1% by weight.

[0141]

[0142] Table 2 .

[0143] The acetylene conversion of these catalysts was tested following standard procedures. The results are shown in... Figure 5 Among all catalysts, catalyst E2-1.2, containing the NMP ligand, exhibited the highest activity and relatively stable activity over time. Catalyst E12, containing the N-methyl-2-piperidinone ligand, also showed relatively stable and good activity, but its activity was slightly lower than that of E1, which contained the thiosulfate ligand.

[0144] Other catalysts showed lower activity and exhibited gradual deactivation from the outset in the cases of E13 containing 2-pyrrolidone and E15 containing 1-methylpyrrolidine.

[0145] Examples 19 and 20 - Role of Solvents

[0146] Catalysts containing 1% Au were prepared by the following procedure, in each case as complexes with thiosulfate ligands.

[0147] Activated carbon (NORIT ROX 0.8) was ground into powder and sieved to <180 micrometers. Ammonium thiosulfate (0.975 g) and CaCl2 (0.175 g) were dissolved in 17 mL of demineralized water. HAuCl4 solution (Johnson & Co., 0.25 g Au, determined to be 41.76%) was diluted with 17 mL of demineralized water and added to the solution containing ammonium thiosulfate. Carbon powder (24.75 g dry weight) was impregnated with a gold-containing solution using a wet impregnation technique. The impregnated material was allowed to stand for 1 hour and then dried in air at 105 °C for 16 hours to obtain catalyst E19.

[0148] Activated carbon (NORIT ROX 0.8) was ground into powder and sieved to <180 micrometers. Ammonium thiosulfate (0.975 g) was dissolved in 15 mL of demineralized water. HAuCl4 solution (Johnson & Co., 0.25 g Au, determined to be 41.76%) was diluted with 25 mL of acetone and added to the solution containing ammonium thiosulfate. Carbon powder (24.75 g dry weight) was impregnated with a gold-containing solution using a wet impregnation technique. The impregnated material was allowed to stand in flowing air at room temperature for 12 hours, and then dried in air at 105°C for 16 hours to obtain catalyst E20.

[0149] Catalyst testing was performed using sintered reactor tubes. 150 mg of SiC was placed on glass frit, followed by 300 mg of catalyst. A catalyst sample (approximately 300 mg) was loaded onto glass wool inside the reactor tube. The feed stream was prepared by combining acetylene (5% acetylene in argon) at a flow rate of 5.83 mL / min and HCl (5% HCl in argon). Unless otherwise specified, the feed stream temperature was set to 180 °C. Acetylene conversion was determined by gas chromatography. The results are shown in [Table / Insert table here]. Figure 6 middle.

[0150] The catalyst (E19) prepared using an aqueous impregnation solution containing 1% Au initially showed a conversion of approximately 70% and stabilized at approximately 45% conversion. The stable value is approximately 65% ​​of the initial activity.

[0151] Conversely, the catalyst (E20) prepared using an acetone / water impregnation solution initially exhibited approximately 50% conversion and stabilized at approximately 45% conversion. The stability value is approximately 90% of the initial activity. This catalyst displays a much more stable activity profile without the high initial activity. This is expected to be beneficial in avoiding localized hotspots during the initial activation of the catalyst.

[0152] Examples 21 and 22 - Alternative sulfur-containing ligands

[0153] The catalyst (E21) containing 1% Au was prepared following the procedure used for producing E20, except that a solution of sodium thiocyanate (0.530 g) dissolved in 25 mL of acetone was used instead of an aqueous solution of ammonium thiosulfate. The HAuCl4 solution was diluted with 15 mL of acetone instead of 25 mL. The solutions were mixed together and used immediately for impregnating carbon powder.

[0154] The catalyst (E22) containing 0.5% Au was prepared following the procedure used for producing E21, except that a HAuCl4 solution containing 0.125 g Au was used instead of a HAuCl4 solution containing 0.25 g Au. An aqueous solution of ammonium thiosulfate was replaced with a solution of sodium thiocyanate (0.530 g) dissolved in 25 mL of acetone. The HAuCl4 solution was diluted with 15 mL of acetone instead of 25 mL. The solutions were mixed together and used immediately for impregnating carbon powder.

[0155] The results are shown in Figure 7 In each case, the catalyst exhibited stable activity characteristics without initial spikes in catalyst activity. This is expected to help avoid localized hot spots during the initial activation of the catalyst.

[0156] Preparation of [HAuCl4](NMP)2

[0157] 15 ml of acetone was added to 2.50 g of a HAuCl4 (40.02% Au) solution containing 1.00 g Au. Then, 15 ml of acetone solution containing 4 molar equivalents of N-methylpyrrolidine (2.01 g) was added to this solution. The resulting solutions were mixed and allowed to react for 30 minutes. The solution was then evaporated under vacuum to obtain an oily residue. After washing with an equal amount of cyclohexane, a solid product was obtained, which was recrystallized from 1-propanol-cyclohexane to produce a batch of fine, bright yellow needle-like crystals in high yield. Needle-like single crystals suitable for X-ray crystal structure analysis were obtained by slow crystallization from 1-propanol-cyclohexane.

[0158] For AuC 10 Cl4H 19 Elemental analysis of N2O2 required Cl, 26.4%; C, 22.3%; H, 3.6%; N, 5.2%; Measured values: Cl, 26.4%; C, 22.3%; H, 3.5%; N, 5.2%.

[0159] By using wavelength X-ray diffraction analysis at 296 K was performed to determine the single-crystal structure of the material, indicating that it possesses the following properties: monoclinic, space group P21 / n, a = α=90°, β=98.485(7)°, γ=90°, Z=4, crystal size 0.380×0.140×0.090mm 3A total of 4383 independent reflections were collected.

[0160] Figure 8 The image shown illustrates the determined structure, revealing NMP coordination around the AuCl4 center. The N-Au spacing is... and

Claims

1. A method for producing a catalyst for a hydrochlorination reaction, the method comprising the following steps: i) An impregnation solution is prepared by incorporating a gold source and a ligand in a solvent, wherein the solvent comprises an organic solvent, the organic solvent comprising or consisting of acetone; ii) Impregnate the carrier with the impregnation solution from step (i); and iii) Dry the product of step (ii) to obtain the catalyst; The ligands described herein have formula (I) in X is O or S; n is 1 or 2; R is H or optionally contains one or more heteroatoms selected from fluorine, chlorine, bromine, iodine, oxygen, or nitrogen, and is a C1 to C10 hydrocarbon group.

2. The method according to claim 1, wherein the solvent is composed of the organic solvent.

3. The method according to claim 1, wherein the solvent is composed of a mixture of an organic solvent and water.

4. The method according to claim 1, wherein the ligand is N-methyl-2-pyrrolidone.

5. A hydrochlorination reaction catalyst, said hydrochlorination reaction catalyst comprising a complex of a gold and a ligand of formula (I). in X is O or S; n is 1 or 2; R is H or optionally contains one or more heteroatoms selected from fluorine, chlorine, bromine, iodine, oxygen, or nitrogen, and is a C1 to C10 hydrocarbon group; and The complex is loaded onto a carrier.

6. The catalyst according to claim 5, wherein the ligand is N-methyl-2-pyrrolidone.

7. The catalyst according to claim 5, wherein the support is in the form of powder, granules or shaped particles.

8. The catalyst according to claim 5, wherein the support is a carbon support.

9. A method for catalytically hydrochlorinating a substrate containing an alkyne unit, wherein the reaction is carried out in the presence of a catalyst according to claim 5 or a catalyst that can be produced by the method according to claim 1.

10. The method of claim 9, wherein the substrate is acetylene.

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