A heterogeneous catalyst and a method for preparing thiols

Abstract

This application relates to the field of chemical technology and discloses a heterogeneous catalyst and a method for preparing thiols. The heterogeneous catalyst comprises an active component and an organophosphorus polymer ligand. The organophosphorus polymer ligand forms a coordination bond with the active component through a phosphorus element in its chemical structure. The active component includes at least one of Co and Rh elements. The organophosphorus polymer ligand is formed by polymerizing and sulfiding an organophosphorus monomer containing a carbon-carbon double bond. The sulfur content is 1%-20% based on the mass of the heterogeneous catalyst. The heterogeneous catalyst of this application exhibits high utilization of the active component and is not easily lost. The phosphorus ligand has a significant steric effect, which can improve the stereoselectivity of the target product. Simultaneously, a certain amount of sulfur can increase the binding force between the catalyst and H₂S, thereby improving the thiol yield.

Description

Technical Field

[0001] This application relates to the field of chemical technology, specifically to a heterogeneous catalyst and a method for preparing thiols. Background Technology

[0002] Thiols are a class of non-aromatic compounds containing a thiol functional group (-SH), and can be used as rubber vulcanization accelerators, regulators, and surfactants. Industrial production of thiols typically involves the addition reaction of olefins with hydrogen sulfide or the reaction of the corresponding alcohol with hydrogen sulfide. The addition reaction of olefins with hydrogen sulfide generally employs photocatalysis, free radical catalysis, or acid catalysis, but the reaction conditions are harsh, requiring high purity of raw materials, posing significant technical challenges, and resulting in poor yields. Regarding the reaction of alcohols with hydrogen sulfide, because the boiling points of thiols are close to those of their corresponding alcohols, product separation is difficult when the conversion rate of the raw alcohol is insufficient. Therefore, there is an urgent need to develop a highly industrially viable method for the preparation of thiols to address the problems associated with the aforementioned two production processes. Summary of the Invention

[0003] In view of this, this application provides a heterogeneous catalyst and a method for preparing thiols using the heterogeneous catalyst, in order to solve the problems of harsh reaction conditions, difficult product separation and poor reaction yield in existing thiols production processes.

[0004] According to an embodiment of this application, in a first aspect, a heterogeneous catalyst is provided, comprising an active component and an organophosphorus polymer ligand, wherein the organophosphorus polymer ligand forms a coordination bond with the active component through a P element in its chemical structure;

[0005] The active component includes at least one of the elements Co and Rh;

[0006] The organophosphorus polymer ligand is formed by polymerizing and sulfiding organophosphorus monomers including carbon-carbon double bonds, and the sulfur content is 1%-20% based on the mass of the heterogeneous catalyst.

[0007] The heterogeneous catalyst provided in this application utilizes the polymerization reaction between carbon-carbon double bonds in organophosphorus monomers to form organophosphorus polymers with a hierarchical porous structure. The organophosphorus polymer backbone contains a large number of phosphorus elements with lone pairs of electrons, which can form multiple coordinate bonds with the empty orbitals of the active component metal elements. This allows the active component to be uniformly dispersed in the organophosphorus polymer support, significantly improving the utilization rate of the active component and ensuring that it is not easily lost, thus extending the catalyst's lifespan. Simultaneously, the phosphorus ligands exhibit significant steric effects, improving the stereoselectivity of the target product. Furthermore, the heterogeneous catalyst of this application pre-sulfurizes the organophosphorus polymer ligands, resulting in the presence of a certain amount of sulfur, which increases the binding force between the catalyst and H₂S, thereby improving the mercaptan yield. This application's research found that if the sulfur content in the organophosphorus polymer ligands is too high, it leads to excessive sulfur content around the active component, inhibiting the binding of the active component with olefins; conversely, if the sulfur content is too low, it does not significantly contribute to improving the mercaptan yield.

[0008] In some optional embodiments, the vulcanization step includes reacting the polymerized product of the organophosphorus monomer with sulfur at 110°C-150°C for 4-10 hours. This allows hydrogen on the backbone of the organophosphorus monomer polymer to undergo a substitution reaction with sulfur, forming a sulfur-doped organophosphorus polymer. If the reaction temperature is too low or the time is too short, there will be too few thiolated sites, resulting in little improvement in the thiol yield. If the reaction temperature is too high or the time is too long, it will lead to the breakage of the thiol mercapto groups, affecting the vulcanization yield.

[0009] It is understood that, in some optional embodiments, the content of the active component is 0.001%-3% based on the mass of the heterogeneous catalyst, and / or the content of the organophosphorus polymer ligand is 97%-99.999%. This ensures that the active component can bind well with the polymer ligand, thereby guaranteeing high catalytic activity and selectivity.

[0010] For example, the organophosphorus monomer includes at least one of the following compounds:

[0011]

[0012] This study found that, compared to triphenylphosphine, organophosphine monomers with nitrogen-containing aromatic groups, as shown in formulas (3) and (4), can enhance the coordination ability of phosphorus elements, thereby improving the stability of the catalyst. Organophosphine monomers with structures shown in formulas (5) to (12), due to their bidentate coordination ability, can increase the chelation ratio between organophosphorus polymer ligands and active components, thereby increasing the proportion of olefins bound to active components via terminal double bonds and improving the selectivity of primary thiols. Unlike the PC bonds in other organophosphorus monomers, the bidentate phosphate ester monomers formed by constructing PO bonds in formulas (11) and (12) have better coordination activity and can better bind to internal olefins, allowing the double bonds of internal olefins to migrate to the terminal positions and react with CO, H2, and H2S, thereby improving the conversion rate of internal olefins and the selectivity of primary thiols.

[0013] It is understandable that internal alkenes refer to alkenes whose carbon-carbon double bonds are not at the ends of the molecular chain, while terminal alkenes refer to alkenes whose carbon-carbon double bonds are located at the ends of the molecular chain.

[0014] It should be noted that the heterogeneous catalyst can be prepared by a commonly used solvothermal polymerization method. In some optional embodiments, the preparation method of the heterogeneous catalyst includes the following steps:

[0015] S1: Mix organophosphorus monomers, free radical initiators, and solvents at 20℃-60℃ and under an inert gas protective atmosphere, and stir for 0.5-20 hours.

[0016] S2: Under an inert gas protective atmosphere at 80℃-150℃, the suspension obtained in S1 is transferred to a high-pressure reactor for solvothermal polymerization reaction, with a reaction time of 0.5-20 hours.

[0017] S3: The solvent in the suspension obtained in S2 is removed under vacuum at 40℃-100℃ to obtain the polymer product of organophosphorus monomer;

[0018] S4: The polymer product obtained in S3 is subjected to a sulfurization reaction with sulfur at 110℃-150℃ for 4-10 hours to obtain organophosphorus polymer ligands;

[0019] S5: The organophosphorus polymer ligand obtained in S4 is placed in a solvent containing an active metal salt and stirred for 0.5-40 hours at 10℃-100℃ under an inert gas protective atmosphere. Then, the solvent is removed under vacuum at 40℃-100℃ to obtain a heterogeneous catalyst.

[0020] For example, the solvent includes one or more of benzene, toluene, xylene, cyclohexane, tetrahydrofuran, methanol, ethanol, dichloromethane, and dichloroethane; the free radical initiator includes one or more of benzoyl peroxide, tert-butyl hydroperoxide, and azobisisobutyronitrile, and the amount of free radical initiator is 0.1%-5% of the mass of the organophosphorus monomer; the amount of sulfur is 1%-40% of the mass of the polymerization product obtained in S3; the active metal salt includes inorganic and / or organic salts of cobalt and / or rhodium, preferably in the form of acetate, isooctanoate, naphthenate, or acetylacetonate. The chemical structure of the organophosphorus monomer is as described above and will not be repeated here.

[0021] According to embodiments of this application, a second aspect provides the application of the heterogeneous catalyst described in the first aspect in a thiol preparation process.

[0022] According to embodiments of this application, a third aspect also provides a method for preparing thiols, comprising the following steps:

[0023] In the presence of the heterogeneous catalyst described in the first aspect, olefins react with CO, H2, and H2S, with the volume hourly space velocity (VHSV) of the CO, H2, and H2S mixture controlled at 0.1 h⁻¹. -1 -50h -1 The reaction temperature is 80℃-150℃ and the reaction pressure is 0.5MPa-10MPa to produce thiols.

[0024] This application employs a novel process flow under the catalytic action of the heterogeneous catalyst described in the first aspect. By controlling the reaction temperature, pressure, and gas rate, olefins can directly react with carbon monoxide, hydrogen sulfide, and hydrogen to introduce a mercaptomethyl group at the olefin terminal, generating a thiol with one more carbon atom than the olefin. The thiol preparation method provided by this application simplifies the synthesis process. The heterogeneous catalyst used is not only easy to separate but also avoids the harsh conditions of photocatalysis, peroxide catalysis, or acid catalysis. Furthermore, the boiling points of the feed olefin and the target product thiol differ significantly, so even incomplete conversion of the feed olefin does not affect product separation, reducing energy consumption for feed olefin and product separation and significantly lowering product production costs.

[0025] In some optional embodiments, the volume hourly space velocity (VHSV) of the mixture of CO, H2, and H2S is 1 h⁻¹. -1 -30h -1 The gas space velocity is adjusted according to the reactivity of different olefins, so that the reaction efficiency and heat of reaction removal can be better balanced within the above range.

[0026] In some alternative embodiments, the reaction temperature is 100℃-130℃, which better balances the reaction rate and catalyst stability. This application's research found that if the reaction temperature is too low (below 80℃), the reaction rate is too slow, affecting efficiency, while if the temperature is too high (above 150℃), the effective components of the catalyst are easily detached, affecting its service life.

[0027] In some alternative embodiments, the reaction pressure is 1.5 MPa-5 MPa to ensure a more suitable reaction rate. This application found that if the reaction pressure is too low (less than 0.5 MPa), the binding of the gas to the active component is difficult to occur, affecting the feed conversion rate; while if the reaction pressure is too high (greater than 10 MPa), the binding force between gases such as CO and the ligands of the active metal is too strong to detach, thus inhibiting the reaction rate.

[0028] In some alternative embodiments, when C2-C4 olefins are used, the mass flow rate of the olefins is 0.01-0.5 g / (h·mL catalyst), thereby adjusting the feed rate according to the reaction rate of different olefins, controlling the conversion rate and exothermic power, and thus maintaining the stability of the reaction temperature and the selectivity of the target product.

[0029] In some alternative embodiments, at least one of the following conditions is met: a. the molar ratio of H2S to H2 is 0.4-2.5:1; b. the molar ratio of CO to H2 is 0.4-1.2:1; c. the molar ratio of olefin to CO is 1.0-5.0:1. This allows for better control of the selectivity of thiols in the reaction and avoids excessively high selectivity for byproducts such as aldehydes, alcohols, and alkanes.

[0030] In some alternative embodiments, the olefin is a C2-C20 monoolefin, and exemplaryly may be at least one of propylene, 1-butene, 2-butene, 1-pentene, 1-hexene, 1-heptene, 2-heptene, 1-octene, 1-undecene, 2-methyl-1-decene, 5-methyl-5-decene, 8-methyl-1-decene, and 2,4,4,6-tetramethyl-2-heptene.

[0031] It is understood that the reaction to prepare thiols is carried out in a reactor, which may be a fixed-bed reactor or a bubble-bed reactor, for example.

[0032] The technical solution of this application has the following advantages:

[0033] The heterogeneous catalyst provided in this application includes an active component and an organophosphorus polymer ligand. The organophosphorus polymer ligand forms a coordination bond with the active component through a phosphorus element in its chemical structure. The active component includes at least one of Co and Rh elements. The organophosphorus polymer ligand is formed by polymerizing and sulfiding an organophosphorus monomer containing a carbon-carbon double bond. The sulfur content is 1%-20% based on the mass of the organophosphorus polymer ligand. The heterogeneous catalyst of this application has high utilization of the active component and is not easily lost. The phosphorus ligand has a significant steric effect, which can improve the stereoselectivity of the target product. At the same time, a certain amount of sulfur can increase the binding force between the catalyst and H2S, thereby improving the yield of thiols.

[0034] The method for preparing thiols provided in this application employs a novel process flow under the catalysis of a heterogeneous catalyst. By controlling the reaction temperature, pressure, and gas rate, olefins can directly react with carbon monoxide, hydrogen sulfide, and hydrogen to introduce a mercaptomethyl group at the olefin terminal, thereby producing thiols. This method features a short process route, mild reaction conditions, simple operation, and easy product separation, significantly reducing the production cost of thiols.

[0035] Additional aspects and advantages of the embodiments of this application will be described and shown in part in the following description, or illustrated by practice of the embodiments of this application. Detailed Implementation

[0036] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] For any experimental steps or conditions not specified in the following examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0038] The reagents used in the embodiments and comparative examples of this application are as follows:

[0039] The mixture of propylene, carbon monoxide, hydrogen sulfide, and hydrogen was purchased from Air Products.

[0040] 2-Heptene, 1-Undecene, and vinyl monomers were purchased from Beijing Innocare Technology Co., Ltd.

[0041] Rhodium acetylacetone, cobalt acetate, rhodium acetate, and triphenylphosphine were purchased from Aladdin Reagent Co., Ltd.

[0042] The main test methods described in the embodiments and comparative examples of this application are as follows:

[0043] The conversion rate of reactants and the selectivity of the product were determined by gas chromatography using the internal standard method. The reactant conversion rate was calculated as: (moles of reactant - moles of reactant remaining after reaction) / (moles of reactant) × 100%. The product selectivity was calculated as: (moles of product after reaction) / (moles of reactant - moles of reactant remaining after reaction) × 100%. The gas chromatograph used was an Agilent Technologies GC-7820, with a 0.25 mm × 30 m DB-5 capillary column. The column oven temperature was programmed to increase from 40 °C to 280 °C at a rate of 15 °C / min and maintained for 5 min. An FID detector was used. The vaporization chamber temperature was 280 °C, the detector temperature was 300 °C, the argon flow rate was 2.1 mL / min, the hydrogen flow rate was 30 mL / min, the air flow rate was 400 mL / min, and the injection volume was 1.0 μL.

[0044] Unless otherwise specified, the conversion rate and selectivity percentages used in the embodiments and comparative examples of this invention are all molar percentages, and the purity content of substances are all mass percentages. The unit barA represents absolute pressure, which is the actual pressure acting directly on the surface of a container or object, with its zero point being absolute vacuum. The unit MPaG represents gauge pressure, which is the pressure value relative to atmospheric pressure, excluding atmospheric pressure itself.

[0045] Preparation Example 1: Preparation of Catalyst A

[0046] 1000g of tetrahydrofuran, 190g of monomer of formula (4), and 5g of azobisisobutyronitrile were added to a 2L pressure-resistant stirred reactor with a heat transfer inner coil under a nitrogen atmosphere, and the mixture was stirred at 50℃ for 3h. Then, the temperature was raised to 120℃ for thermal polymerization, and the reaction was carried out for 10h. The resulting reaction solution was transferred to a rotary evaporator, and tetrahydrofuran was removed at 50℃ and 0.5barA. The obtained polymer was vulcanized with 2g of sulfur at 120℃ for 6h to obtain 176g of organophosphorus polymer ligand. 14g of cobalt acetate was dissolved in 200g of ethanol to prepare a solution, and the obtained organophosphorus polymer ligand was immersed in the solution. The mixture was stirred at 10℃ for 8h under a nitrogen atmosphere, filtered, and the solid obtained was subjected to a process at 40℃ and 0.9barA to remove residual dichloromethane to obtain catalyst A.

[0047] Based on the total mass of catalyst A, the test results showed that the cobalt content in catalyst A was 2.4% and the sulfur content was 1.1%.

[0048] Preparation Example 2: Preparation of Catalyst B

[0049] 1000g of toluene, 200g of monomer of formula (6), and 2g of benzoyl peroxide were added to a 2L pressure-resistant stirred reactor with a heat transfer inner coil under a nitrogen atmosphere, and the mixture was stirred at 40℃ for 2h. Then, the temperature was raised to 100℃ for thermal polymerization, and the reaction was carried out for 6h. The resulting reaction solution was transferred to a rotary evaporator and toluene was removed at 60℃ and 0.2barA. The obtained polymer was vulcanized with 26g of sulfur at 110℃ for 8h to obtain 183g of organophosphorus polymer ligand. 0.1g of rhodium acetylacetone was dissolved in 200g of toluene to prepare a solution, and the obtained organophosphorus polymer ligand was immersed in the solution and stirred at 70℃ for 6h under a nitrogen atmosphere. After filtration, the solid was subjected to toluene removal at 60℃ and 0.2barA to obtain catalyst B.

[0050] Based on the total mass of catalyst B, the test results showed that the rhodium content in catalyst B was 0.007% and the sulfur content was 12.1%.

[0051] Preparation Example 3: Preparation of Catalyst C

[0052] 1000g of ethanol, 200g of monomer of formula (12), and 10g of tert-butyl hydrogen peroxide were added to a 2L pressure-resistant stirred reactor with a heat transfer inner coil under a nitrogen atmosphere, and the mixture was stirred at 60℃ for 2h. Then, the temperature was raised to 110℃ for thermal polymerization, and the reaction was carried out for 8h. The resulting reaction solution was transferred to a rotary evaporator, and the ethanol was removed at 60℃ and 0.3 barA. The obtained polymer was vulcanized with 30g of sulfur at 150℃ for 4h to obtain 147g of organophosphorus polymer ligand. 6.5g of rhodium acetate was dissolved in 200g of methanol to prepare a solution, and the obtained organophosphorus polymer ligand was immersed in the solution. The mixture was stirred at 70℃ for 6h under a nitrogen atmosphere, filtered, and the obtained solid was deethanolerated at 70℃ and 0.3 barA to obtain catalyst C.

[0053] Based on the total mass of catalyst C, the test results showed that the rhodium content in catalyst C was 1.3% and the sulfur content was 17%.

[0054] Preparation Example 4: Preparation of Catalyst D

[0055] Catalyst D was prepared using a method essentially the same as that used in Preparation Example 3, except that the vinyl monomer used was trivinylphenylphosphine as shown in Formula (1).

[0056] Based on the total mass of catalyst D, the test results showed that catalyst C contained 1.3% rhodium and 17% sulfur.

[0057] Example 1: Synthesis of n-Butanethiol

[0058] A 100 mL jacketed fixed-bed reactor was used, packed with 80 mL of catalyst A, under a carbon monoxide + hydrogen sulfide + hydrogen atmosphere. The reaction pressure was 2 MPaG, and the temperature was 100 °C. Propylene was introduced at a flow rate of 3.38 g / h, and a mixture of carbon monoxide + hydrogen sulfide + hydrogen (25.00% carbon monoxide, 25.00% hydrogen sulfide, and 50.00% hydrogen, all molar percentages) was introduced at a flow rate of 40 mL / min (gas hourly space velocity 30 h⁻¹). -1 The flow rate is from bottom to top through the fixed bed. Sampling and analysis at the outlet showed a propylene conversion of 91.1% and a selectivity of 95.7% for n-butanethiol.

[0059] Example 1-1

[0060] The method is basically the same as that in Example 1, except that the reaction pressure is 3.5 MPaG and the temperature is 120°C.

[0061] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 92.4% and a selectivity of 95.4% for n-butanethiol.

[0062] Examples 1-2

[0063] The method is basically the same as that in Example 1, except that the reaction pressure is 5 MPaG and the temperature is 130°C.

[0064] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 92.8% and a selectivity of 94.8% for n-butanethiol.

[0065] Examples 1-3

[0066] The method is basically the same as that in Example 1, except that the reaction pressure is 10 MPaG and the temperature is 150°C.

[0067] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 76.4% and a selectivity of 83.4% for n-butanethiol.

[0068] Examples 1-4

[0069] The method is basically the same as that in Example 1, except that the reaction pressure is 0.5 MPaG and the temperature is 80°C.

[0070] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 64.8% and a selectivity of 93.6% for n-butanethiol.

[0071] Examples 1-5

[0072] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 15 h⁻¹. -1 .

[0073] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 93.2% and a selectivity of 94.5% for n-butanethiol.

[0074] Examples 1-6

[0075] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 1 h⁻¹. -1 .

[0076] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 93.7% and a selectivity of 94.0% for n-butanethiol.

[0077] Examples 1-7

[0078] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 0.1 h⁻¹. -1 .

[0079] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 96.1% and a selectivity of 87.5% for n-butanethiol.

[0080] Examples 1-8

[0081] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 50 h⁻¹. -1 .

[0082] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 72.1% and a selectivity of 95.8% for n-butanethiol.

[0083] Examples 1-9

[0084] The method is basically the same as in Example 1, except that the composition of the mixed gas is CO, H2 and H2S in molar ratios of 25.64%, 23.08% and 51.28%, respectively.

[0085] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 90.5% and a selectivity of 93.2% for n-butanethiol.

[0086] Examples 1-10

[0087] The method is basically the same as in Example 1, except that the composition of the mixed gas is CO, H2 and H2S in a molar ratio of 23.26%, 30.23% and 46.51%.

[0088] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 91.0% and a selectivity of 95.3% for n-butanethiol.

[0089] Examples 1-11

[0090] The method is basically the same as in Example 1, except that the composition of the mixed gas is CO, H2 and H2S in a molar ratio of 22.22%, 22.22% and 55.56%.

[0091] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 92.3% and a selectivity of 93.9% for n-butanethiol.

[0092] Examples 1-12

[0093] The method is basically the same as in Example 1, except that the composition of the mixed gas is CO, H2 and H2S in a molar ratio of 23.26%, 23.26% and 53.48%.

[0094] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 92.0% and a selectivity of 94.2% for n-butanethiol.

[0095] Examples 1-13

[0096] The method is basically the same as in Example 1, except that the propylene flow rate is 1.13 g / h.

[0097] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 93.7% and a selectivity of 92.9% for n-butanethiol.

[0098] Examples 1-14

[0099] The method is basically the same as in Example 1, except that the propylene flow rate is 2.51 g / h.

[0100] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 93.2% and a selectivity of 93.3% for n-butanethiol.

[0101] Examples 1-15

[0102] The method is basically the same as in Example 1, except that the propylene flow rate is 5.63 g / h.

[0103] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 85.4% and a selectivity of 95.5% for n-butanethiol.

[0104] Examples 1-16

[0105] The method is basically the same as that in Example 1, except that catalyst D is used instead of catalyst A.

[0106] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 81.3% and a selectivity of 91.2% for n-butanethiol.

[0107] Example 2: Synthesis of n-Octamethasone

[0108] A 100 mL jacketed fixed-bed reactor was used, packed with 80 mL of catalyst C, under a carbon monoxide + hydrogen sulfide + hydrogen atmosphere. The reaction pressure was 4 MPaG, and the temperature was 110 °C. 2-Heptene was introduced into the fixed bed at a flow rate of 76.1 g / h, while a mixture of carbon monoxide + hydrogen sulfide + hydrogen (21.74% carbon monoxide, 28.26% hydrogen sulfide, and 50.00% hydrogen, all by volume) flowed downwards at a flow rate of 266.7 mL / min. Analysis at the outlet showed a 2-heptene conversion of 88.1% and a selectivity of 97.8% for n-octylthiol.

[0109] Example 3: Synthesis of n-Octamethasone

[0110] The method is basically the same as in Example 2, except that catalyst D is used instead of catalyst C.

[0111] Analysis of samples taken at the export point showed a 2-heptene conversion rate of 73.2% and a n-octylthiol selectivity of 32.1%.

[0112] Example 4: Synthesis of n-dodecyl mercaptan

[0113] A 100 mL jacketed fixed-bed reactor was used, packed with 80 mL of catalyst B, under a carbon monoxide + hydrogen sulfide + hydrogen atmosphere. The reaction pressure was 3 MPaG, and the temperature was 100 °C. 1-Undecene was fed from top to bottom through the fixed bed at a flow rate of 100 g / h, while a mixture of carbon monoxide + hydrogen sulfide + hydrogen (22.72% carbon monoxide, 20.45% hydrogen sulfide, and 56.83% hydrogen, all by volume) flowed downwards. Analysis at the outlet showed a 1-undecene conversion of 67.4% and a selectivity of 86.1% for n-dodecyl mercaptan.

[0114] Example 5: Synthesis of n-dodecyl mercaptan

[0115] The method is basically the same as in Example 4, except that catalyst D is used instead of catalyst B.

[0116] Sampling and analysis at the export point showed a 1-undecene conversion rate of 53.2% and a n-dodecyl mercaptan selectivity of 75.9%.

[0117] Comparative Example 1

[0118] The method is basically the same as in Example 1, except that catalyst DA is used. The preparation method of catalyst DA is as follows:

[0119] 1000g of tetrahydrofuran, 190g of monomer of formula (4), and 5g of azobisisobutyronitrile were added to a 2L pressure-resistant stirred reactor with a heat transfer inner coil under a nitrogen atmosphere, and the mixture was stirred at 50℃ for 3h. Then the temperature was raised to 120℃ for thermal polymerization, and the reaction was carried out for 10h. The resulting reaction solution was transferred to a rotary evaporator, and tetrahydrofuran was removed at 50℃ and 0.5barA to obtain the polymer. 14g of cobalt acetate was dissolved in 200g of dichloromethane to prepare a solution, and the obtained polymer was immersed in the solution. The mixture was stirred at 10℃ for 8h under a nitrogen atmosphere, and then the dichloromethane was removed at 40℃ and 0.9barA to obtain catalyst DA. The cobalt content in catalyst DA was found to be 2.4% based on the total mass of catalyst DA.

[0120] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 36.2% and a selectivity of 0.002% for n-butanethiol.

[0121] Comparative Example 2

[0122] The method is basically the same as in Example 1, except that the fixed-bed reactor is filled with 80 mL of catalyst DA (prepared by the same method as Comparative Example 1) and 2 mL of sulfur uniformly dispersed around the catalyst DA.

[0123] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 2.4% and a selectivity of 0.001% for n-butanethiol.

[0124] Comparative Example 3

[0125] The method is basically the same as in Example 1, except that the reaction temperature is 160°C.

[0126] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 52.6% and a selectivity of 10.1% for n-butanethiol.

[0127] Comparative Example 4

[0128] The method is basically the same as in Example 1, except that the reaction temperature is 70°C.

[0129] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 5.7% and a selectivity of 93.3% for n-butanethiol.

[0130] Comparative Example 5

[0131] The method is basically the same as in Example 1, except that the reaction pressure is 0.4 MPa.

[0132] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 34.4% and a selectivity of 92.5% for n-butanethiol.

[0133] Comparative Example 6

[0134] The method is basically the same as in Example 1, except that the reaction pressure is 11 MPa.

[0135] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 57.1% and a selectivity of 87.7% for n-butanethiol.

[0136] Comparative Example 7

[0137] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 0.05 h⁻¹. -1 .

[0138] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 96.7% and a selectivity of 49.2% for n-butanethiol.

[0139] Comparative Example 8

[0140] The method is basically the same as in Example 1, except that the volume hourly space velocity of the mixed gas is 52 h⁻¹. -1 .

[0141] Analysis of samples taken at the reactor outlet showed a propylene conversion rate of 63.7% and a selectivity of 91.3% for n-butanethiol.

[0142] As can be seen from the above examples and comparative examples, when sulfidation is not performed during catalyst preparation, the selectivity of thiols in the final product is very low; when sulfur is dispersed around the catalyst in the form of elemental form, it will become an inhibitor of the reaction, resulting in not only a low reaction rate but also low thiols selectivity; when process conditions such as temperature, pressure, or feed rate deviate from the appropriate range, the reaction can occur, but the reaction rate or selectivity is difficult to achieve optimal indicators.

[0143] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A heterogeneous catalyst characterized in that, The active component and the organic phosphine polymer ligand form a coordination bond through the P element in the chemical structure of the organic phosphine polymer ligand; The active component comprises at least one of Co and Rh elements; The organic phosphine polymer ligand is obtained by polymerization and vulcanization of an organic phosphine monomer comprising a carbon-carbon double bond; the vulcanization step comprises: reacting the polymerization product of the organic phosphine monomer with sulfur at 110-150°C for 4-10h; The content of sulfur is 1%-20% based on the mass of the heterogeneous catalyst; The content of the active component is 0.001%-3% and the content of the organic phosphine polymer ligand is 97%-99.999% based on the mass of the heterogeneous catalyst; The organic phosphine monomer comprises at least one of the following compounds: 。 2. Use of the heterogeneous catalyst of claim 1 in a mercaptan preparation process.

3. A method for preparing a mercaptan, characterized by, The process comprises the following steps: In the presence of the heterogeneous catalyst of claim 1, olefin is reacted with CO, H2 and H2S, the volume space velocity of the mixed gas of CO, H2 and H2S is controlled to be 0.1 h -1 -50h -1 - 10 MPa, and the reaction temperature is 80℃ - 150℃, to produce mercaptan.

4. The method of claim 3, wherein the thiol is prepared by the reaction of a thiol precursor with a reducing agent. The volumetric space velocity of the mixed gas of CO, H2 and H2S is 1 h -1 -30 h -1 .

5. The method of claim 3, wherein the thiol is prepared by the reaction of a thiol precursor with a reducing agent. The reaction temperature is 100-130°C.

6. The method for preparing thiols according to claim 3, characterized in that, The reaction pressure is 1.5-5MPa.

7. The method of claim any one of claims 3 to 6, wherein the thiol is prepared by, When C2-C4 olefins are used, the mass flow rate of the olefins is 0.01-0.5g / (h·mL catalyst).

8. The method of claim any one of claims 3-6, wherein the thiol is prepared by, At least one of the following conditions is met: a. The molar ratio of H2S to H2 is 0.4-2.5:1; b. The molar ratio of CO to H2 is 0.4-1.2:1; c. The molar ratio of olefins to CO is 1.0-5.0:

1.

9. The method of claim any one of claims 3-6, wherein the thiol is prepared by, The olefins are C2-C20 monoolefins.

10. The method for preparing thiols according to claim 9, characterized in that, The C2-C20 monoolefins are at least one of propylene, 1-butene, 2-butene, 1-pentene, 1-hexene, 1-heptene, 2-heptene, 1-octene, 1-undecene, 2-methyl-1-decene, 5-methyl-5-decene, 8-methyl-1-decene, and 2,4,4,6-tetramethyl-2-heptene.

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