A catalyst, its preparation and use

Abstract

The application provides a catalyst, a preparation method and application thereof. The catalyst comprises a carrier and copper and / or cobalt supported on the carrier; the carrier comprises a carbon body and a first carrier compound and a second carrier compound supported on the carbon body. The catalyst is used to catalyze the preparation of adipic acid from cyclohexene, green conversion of cyclohexene can be realized, and the catalyst has high conversion rate and adipic acid selectivity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalytic synthesis, and particularly relates to a catalyst and a preparation method and application thereof. BACKGROUND

[0002] Adipic acid is one of the most valuable binary acids in aliphatic binary acids. As an important organic chemical raw material, adipic acid can undergo condensation reaction with multifunctional compounds to generate high molecular polymers, which are used for producing polyurethane foam plastics, PA66, PBAT degradable plastics, plasticizers, high-grade lubricating oils, food additives, pharmaceutical intermediates, flavor and fragrance control agents, new monocrystalline materials, plastic foaming agents, coatings, pesticides, adhesives and dyes, and have very wide applications.

[0003] The existing industrial production methods of adipic acid include cyclohexane method and cyclohexene method:

[0004] The production of adipic acid by the cyclohexane method accounts for about 90% of the total production of adipic acid, and the method comprises: preparing cyclohexane by full hydrogenation of pure benzene; preparing cyclohexanol and cyclohexanone (KA oil) by air oxidation of cyclohexane; and generating adipic acid by nitric acid oxidation of KA oil under the action of copper and vanadium catalysts.

[0005] The cyclohexene method comprises: producing cyclohexene by partial hydrogenation of benzene under the action of a catalyst, preparing cyclohexanol by hydration of cyclohexene, and oxidizing cyclohexanol into adipic acid by nitric acid.

[0006] The above production methods have mature processes, high yield and high purity of prepared adipic acid, but inevitably use nitric acid as an oxidant, which causes serious corrosion of equipment and serious pollution of nitrogen oxides to the environment, and cannot meet the current requirements of green chemical industry.

[0007] In order to solve the above problems, researchers have developed a green catalytic oxidation preparation process of adipic acid, which uses hydrogen peroxide as an oxidant to catalytically oxidize cyclohexene to prepare adipic acid. Hydrogen peroxide is a clean oxidant, and its reaction product is water, which can fundamentally avoid pollution generated in the oxidation process. For example, Sato et al. (Science, 1998, 281: 1646-1648.) developed a method for directly oxidizing cyclohexene to synthesize adipic acid by using sodium tungstate as a catalyst, [CH3(n-C8H 17 )3N]HSO4 as a phase transfer agent, and 30% hydrogen peroxide as an oxidant. The molar ratio of cyclohexene, sodium tungstate and phase transfer agent is 100:1:1, and the yield of adipic acid reaches 93%. However, the phase transfer agent is highly toxic and causes high environmental pollution, and is difficult to popularize.

[0008] Patent CN102766037B reports that titanium silicalite and poly-metallic oxygen acid or poly-metallic oxygen acid salt are used as catalysts to contact cyclohexene with hydrogen peroxide oxidant to realize the oxidation of cyclohexene to produce adipic acid. The selectivity of adipic acid is good, the activity and stability of the catalyst are high, the equipment corrosion is small, and the environment is friendly. Patent CN102850205B discloses that zinc modified titanium silicalite is used for the oxidation of cyclohexene to produce 1,2-cyclohexanediol and adipic acid. The catalyst is prepared by simply calcining a zinc compound and a heteroatom molecular sieve, and adipic acid is obtained under mild conditions by using hydrogen peroxide as an oxidant. However, the above two methods use organic solvents such as methanol, acetone and acetonitrile, which pollute the environment to a certain extent, and the conversion rate of cyclohexene or the selectivity of adipic acid is low, resulting in low yield of adipic acid.

[0009] Therefore, how to realize the green conversion of cyclohexene and improve the yield of adipic acid is a problem to be solved by those skilled in the art. SUMMARY

[0010] The present application provides a catalyst which can convert cyclohexene to adipic acid in a green and environmentally friendly manner, and the conversion rate of cyclohexene and the selectivity of adipic acid are high.

[0011] The present application also provides a preparation method of a catalyst, which can avoid the use of toxic substances and effectively convert cyclohexene to adipic acid.

[0012] The present application further provides a method for preparing adipic acid by oxidizing cyclohexene, which is more environmentally friendly, and the selectivity of adipic acid obtained is as high as 65%, and the conversion rate of cyclohexene is as high as 80%.

[0013] The present application provides a catalyst comprising a carrier and copper and / or cobalt supported on the carrier; the carrier comprises a carbon body and a first carrier compound and a second carrier compound supported on the carbon body;

[0014] The first carrier compound comprises at least one of NiO, ZnO and Fe2O3; the second carrier compound comprises at least one of ZnX, NiX and FeX2, and X is at least one selected from S, Se and Te.

[0015] According to an embodiment of the present application, the catalyst further comprises nitrogen element.

[0016] The present application also provides a preparation method of a catalyst, comprising the following steps: reducing a reaction system comprising copper salt and / or cobalt salt, carrier and reducing agent to obtain the catalyst.

[0017] According to an embodiment of the present application, the mass ratio of the copper salt and / or cobalt salt to the carrier is 1:(10-100).

[0018] According to an embodiment of the present application, the carrier is prepared by a method comprising the following steps:

[0019] 1) performing a calcination process on a mixture comprising a first metal source, an organic carbon source, and a nitrogen source, wherein the nitrogen source reduces the organic carbon source into a carbon body, and the first metal source is oxidized into a first carrier compound, thereby obtaining a nitrogen-doped carbon body loaded with the first carrier compound;

[0020] 2) co-calcinating the nitrogen-doped carbon body loaded with the first carrier compound with an oxygen group element, thereby obtaining the carrier.

[0021] According to an embodiment of the present application, the molar ratio of the metal element in the first metal source to the carbon element in the organic carbon source and the nitrogen element in the nitrogen source is 1:(4-50):(0.5-4).

[0022] According to an embodiment of the present application, the mass ratio of the oxygen group element to the carbon loaded with the first carrier compound is 1:(5-20).

[0023] According to an embodiment of the present application, the co-calcination in step 2) is performed in an inert gas atmosphere, the inert gas flows from upstream to downstream, the oxygen group element is placed upstream of the carbon body loaded with the first carrier compound, the flow rate of the inert gas is 20-50 mL / min, the calcination process is performed at a temperature of 300-500℃ for a time period of 0.5-2h.

[0024] The present application further provides a method for preparing adipic acid by oxidizing cyclohexene, comprising the following steps: using the catalyst described above, or the catalyst prepared by the method described above, to make the system comprising cyclohexene and an oxidizing agent undergo an oxidation reaction, thereby obtaining adipic acid.

[0025] According to an embodiment of the present application, the oxidizing agent is an aqueous hydrogen peroxide solution, the temperature of the oxidation reaction is 60-120℃, the molar ratio of cyclohexene to hydrogen peroxide is 1:(2-15), and the mass ratio of the catalyst to cyclohexene is 1:(5-200).

[0026] The present application can convert cyclohexene into adipic acid by selecting a carrier loaded with copper and / or cobalt as a catalyst, the carrier comprising a carbon body and a first carrier compound and a second carrier compound loaded on the carbon body, the conversion process is safe and environmentally friendly, the conversion rate of cyclohexene can be as high as 65%, and the selectivity of adipic acid can be as high as 80%. DETAILED DESCRIPTION

[0027] In order for those skilled in the art to better understand the solutions of the present application, the present application is further described in detail below. The specific embodiments listed below are only to describe the principles and characteristics of the present application, and the examples are only to explain the present application, and not to limit the scope of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] The first aspect of the present application provides a catalyst comprising a carrier and copper and / or cobalt supported on the carrier; the carrier comprises a carbon body and a first carrier compound and a second carrier compound supported on the carbon body;

[0029] The first carrier compound comprises at least one of NiO, ZnO, Fe2O3; the second carrier compound comprises at least one of ZnX, NiX, FeX2, X is at least one selected from S, Se, Te.

[0030] By using the catalyst with the above composition to catalyze cyclohexene, cyclohexene can be successfully converted into adipic acid, with high cyclohexene conversion rate and adipic acid selectivity, and without using toxic or corrosive substances such as phase transfer agent, nitric acid, etc., which is safe and environmentally friendly. After analyzing the reasons, the inventors believe that the carbon body has adsorptive properties, which can adsorb the reaction raw materials to the surface of the catalyst, and the copper and / or cobalt, the first carrier compound and the second carrier compound in the catalyst as active components can effectively catalyze cyclohexene, thereby improving the conversion rate of cyclohexene; in addition, the catalyst with the above specific composition can be beneficial to the conversion of cyclohexene into adipic acid.

[0031] It is found through research that when the catalyst further comprises nitrogen element, it is more beneficial to improve the conversion rate of cyclohexene and the selectivity of adipic acid and adipic acid, which may be because the nitrogen element can further improve the adsorption of raw materials such as cyclohexene, thereby enabling the active components to fully exert the catalytic effect.

[0032] In the specific implementation process, the above-mentioned catalyst is prepared by a method comprising the following process:

[0033] The reaction system comprising copper salt and / or cobalt salt, carrier and reducing agent is subjected to a reduction reaction to obtain the catalyst.

[0034] The present application does not limit the specific type of copper salt and / or cobalt salt, for example, the copper salt can be one or more of copper nitrate, copper chloride, copper acetate, copper bromide, copper fluoride, copper phosphate, copper sulfate, copper formate, copper gluconate, copper citrate, copper acetylacetone or copper oxalate; the cobalt source can be one or more of cobalt nitrate, cobalt chloride, cobalt acetate, cobalt bromide, cobalt fluoride, cobalt phosphate, cobalt sulfate, cobalt formate, cobalt gluconate, cobalt citrate, cobalt acetylacetone or cobalt oxalate.

[0035] The present application is also not limited to the type of reducing agent, as long as it can ensure that the copper salt and / or cobalt salt is converted into copper and / or cobalt, for example, it can be a reducing gas H2, NH3, CO.

[0036] In the above reduction reaction process, the reducing agent reduces the copper salt and / or cobalt salt into copper and / or cobalt, and the copper and / or cobalt is loaded on the carrier to obtain the catalyst.

[0037] Through the above method, the copper and / or cobalt can be loaded on the carrier to obtain a catalyst that can catalyze the preparation of adipic acid from cyclohexene.

[0038] The second aspect of the present application provides a method for preparing a catalyst, which comprises the following steps: allowing a reaction system comprising a copper salt and / or a cobalt salt, a carrier and a reducing agent to undergo a reduction reaction to obtain a catalyst. The method is simple to operate, and the obtained catalyst can convert cyclohexene into adipic acid when used to catalyze cyclohexene.

[0039] Further, when the mass ratio of the copper salt and / or cobalt salt to the carrier is controlled to be 1:(10-100), it is more conducive to improving the yield of adipic acid.

[0040] In the present application, the carrier is prepared by a method comprising the following processes:

[0041] 1) performing calcination treatment on a mixture comprising a first metal source, an organic carbon source and a nitrogen source, the nitrogen source reducing the organic carbon source into a carbon body, and the first metal source being oxidized into a first carrier compound, to obtain a nitrogen-doped carbon body loaded with the first carrier compound;

[0042] 2) co-calcining the nitrogen-doped carbon body loaded with the first carrier compound with an oxygen element to obtain the carrier.

[0043] The above-mentioned first metal source refers to an organic and / or inorganic substance containing zinc, iron and nickel elements; the present application does not limit the specific type of the above-mentioned first metal source, which can be zinc salt, iron salt, nickel salt, zinc metal organic framework, nickel metal organic framework, iron metal organic framework, etc. The present application also does not limit the specific type of the anion of the zinc salt, iron salt and nickel salt, which can be nitrate, acetate, phosphate, sulfate, etc.

[0044] The present application also does not limit the specific type of the above-mentioned organic carbon source, which can be glucose, citric acid, oxalic acid, dopamine hydrochloride, starch, cellulose, etc.

[0045] The present application also does not limit the specific type of the above-mentioned nitrogen source, as long as it can reduce the organic carbon source into carbon, which can be melamine, urea, dicyandiamide, cyanamide, pyrrole, polyaniline, etc.

[0046] It can be understood that oxygen element is needed in the process of reducing the first metal source into the first support compound, the present application does not limit the source of oxygen, and the oxygen element can come from the first metal source and / or the nitrogen source for the convenience of operation and cost factors, which is achieved by selecting oxygen-containing first metal salt and / or oxygen-containing nitrogen source, for example, the first metal source is selected from sulfate, and the nitrogen source is selected from melamine, urea, dicyanamide and cyanamide. The present inventors can also add other oxygen-containing substances as long as the nitrogen-doped carbon body loaded with the first support compound can be obtained.

[0047] The above-mentioned chalcogen element refers to at least one of sulfur, selenium and tellurium.

[0048] Through the above-mentioned method, nitrogen element can be introduced into the catalyst to improve the conversion rate of cyclohexene, which is beneficial to obtaining high-yield adipic acid.

[0049] It can be understood that oxygen in the air will further oxidize the carbon body, therefore, the calcination treatment of step 1) is carried out in an inert gas atmosphere, and the inert gas is at least one of nitrogen, argon and helium. The present application does not limit the flow rate of the inert gas as long as the carbon body can be protected from oxidation. Specifically, the flow rate of the inert gas is 40-100 mL / min.

[0050] In order to convert the carbon source into the carbon body, the calcination treatment temperature of step 1) is 400-700°C, and the calcination time is about 3-6 h; the present application does not limit the heating rate, and exemplarily, the heating rate is 2-10°C / min. When the control temperature range is 500-600°C, the utilization rate of the carbon source can be improved, and the carbon source can be fully converted into the carbon body.

[0051] At the same time, in order to further improve the utilization rate of the carbon source, the first metal source and the nitrogen source, the present application further grinds the mixture of the first metal source, the nitrogen source and the carbon source, the grinding time is 20-30 min, and the grinding is carried out in a mortar. After the grinding treatment, the calcination treatment is carried out.

[0052] The present inventors find that when the molar ratio of the metal element in the first metal source to the carbon element in the organic carbon source and the nitrogen element in the nitrogen source is controlled to be 1:(4-50):(0.5-4), the catalytic effect of the catalyst is better, and it is more beneficial to obtain adipic acid. Preferably, the mass ratio of the first metal source to the carbon-containing organic matter and the nitrogen source is 1:(0.8-2):(5-10).

[0053] Further, the mass ratio of the chalcogen element to the carbon loaded with the first support compound is controlled to be 1:(5-20), which can control the amount of the first support compound and the second support compound loaded on the carrier, and obtain a catalyst that is more beneficial to the conversion of cyclohexene. Preferably, the mass ratio of the chalcogen element to the carbon loaded with the first support compound is 1:(8-12).

[0054] In a specific implementation, the co-calcination in step 2) is performed in an inert gas atmosphere, the inert gas flows from upstream to downstream, the oxygen family element is placed upstream of the carbon body loaded with the first carrier compound, the flow rate of the inert gas is 20-50 mL / min, the temperature of the calcination treatment is 300-500°C, and the time is 0.5-2 h.

[0055] The present application is also not limited to the heating rate of the process, which may, for example, be 1-5°C / min.

[0056] During the calcination treatment, the oxygen family element volatilizes and is adsorbed on the carbon body loaded with the first carrier compound. Therefore, in order to improve the adsorption of the carbon body loaded with the first carrier compound for the oxygen family element, the present application places the oxygen family element upstream and controls the flow rate of the inert gas to ensure that the oxygen family element is fully converted into the second carrier compound.

[0057] The third aspect of the present application provides a method for preparing adipic acid by oxidizing cyclohexene, which comprises the following steps: using the aforementioned catalyst or the catalyst prepared by the aforementioned method, and causing the system comprising cyclohexene and an oxidizing agent to undergo an oxidation reaction to obtain adipic acid.

[0058] In a specific implementation, the oxidizing agent is an aqueous hydrogen peroxide solution, the temperature of the oxidation reaction is 60-120°C, the molar ratio of cyclohexene to hydrogen peroxide is 1:(2-15), and the mass ratio of the catalyst to cyclohexene is 1:(5-200). The present application is not limited to the specific concentration of the aforementioned aqueous hydrogen peroxide solution, and in order to improve the conversion rate of cyclohexene, the concentration of the aqueous hydrogen peroxide solution is preferably 10%-50%.

[0059] The method does not require the use of corrosive solvents or phase transfer agents, and can catalytically oxidize cyclohexene into adipic acid with a high yield.

[0060] It should be noted that, in order to ensure that cyclohexene is fully oxidized by hydrogen peroxide and to avoid waste of raw materials, the molar ratio of cyclohexene to hydrogen peroxide is preferably 1:(4-8).

[0061] In addition, when the mass ratio of the aforementioned catalyst to cyclohexene is 1:(50-100), it is more beneficial to improve the conversion rate of cyclohexene and the selectivity of adipic acid.

[0062] The aforementioned reaction can be batch or continuous, and generally, in the case of continuous reaction, the catalytic oxidation of cyclohexene can be achieved in 2-12 h. In a specific implementation, the present application determines whether the conversion of cyclohexene is complete by detecting the amount of cyclohexene using gas chromatography when the amount of cyclohexene no longer changes.

[0063] The present application will be described in more detail below through specific examples.

[0064] In the naming of the embodiments of the present application, the total amount of substance of copper and cobalt is 1, and the subscripts of copper and cobalt represent the amount of substance of copper or cobalt, respectively.

[0065] Example 1

[0066] The catalyst preparation method of the present embodiment comprises the following steps:

[0067] 1) 0.2 g of zinc nitrate, 0.16 g of melamine, and 1.0 g of glucose were mixed and ground for 20 min, and then subjected to calcination treatment under a nitrogen atmosphere to obtain ZnO / C;

[0068] The calcination treatment temperature was 500°C, the time was 3 h, the nitrogen flow rate was 40 mL / min, and the heating rate was 5°C / min;

[0069] 2) 0.5 g of ZnO / C was calcined with 0.0625 g of sulfur under an argon atmosphere to obtain ZnO-ZnS / C;

[0070] The argon gas flowed from upstream to downstream, and the sulfur was placed upstream of the ZnO / C. The argon flow rate was 20 mL / min, the calcination temperature was 300°C, the time was 1 h, and the heating rate was 5°C / min;

[0071] 3) 0.05 g of copper nitrate and 0.06 g of cobalt nitrate were dissolved in 0.5 g of ZnO-ZnS / C and ultrasonicated for 20 min, then stirred for 4 h and dried overnight. The obtained solid was calcined together under the action of H2 at a temperature of 300°C for 4 h to obtain Cu 0.5 Co 0.5 / ZnO-ZnS / C;

[0072] The catalyst Cu 0.5 Co 0.5 / ZnO-ZnS / C of the present embodiment was reacted with cyclohexene and hydrogen peroxide at 60°C for 4 h to obtain the product;

[0073] The molar ratio of cyclohexene to hydrogen peroxide was 1:4, and the mass ratio of the catalyst to cyclohexene was 1:50.

[0074] Example 2

[0075] The catalyst preparation method of the present embodiment comprises the following steps:

[0076] 1) 0.2 g of nickel acetate, 0.2 g of urea, and 1.6 g of citric acid were mixed and ground for 30 min, and then subjected to calcination treatment under a nitrogen atmosphere to obtain NiO / C;

[0077] The calcination treatment temperature was 600°C, the time was 5 h, the nitrogen flow rate was 60 mL / min, and the heating rate was 2°C / min;

[0078] 2) 0.5 g of NiO / C was calcined with 0.05 g of sulfur under an argon atmosphere to obtain NiO-ZnS / C;

[0079] Argon gas flowed from upstream to downstream, and sulfur was placed upstream of the NiO / C. The argon flow rate was 20 mL / min, the calcination temperature was 400°C, the time was 1 h, and the heating rate was 2°C / min;

[0080] 3) 0.03 g of copper nitrate and 0.009 g of cobalt nitrate were calcined with 0.5 g of NiO-ZnS / C under the action of NH3at a temperature of 350°C for 6 h to obtain Cu 0.8 Co 0.2 / NiO-NiS / C;

[0081] The catalyst Cu 0.8 Co 0.2 / NiO-NiS / C of this example was reacted with cyclohexene and hydrogen peroxide at 90°C for 8 h to obtain the product;

[0082] The molar ratio of cyclohexene to hydrogen peroxide was 1:6, and the mass ratio of the catalyst to cyclohexene was 1:50.

[0083] Example 3

[0084] The catalyst preparation method of this example includes the following steps:

[0085] 1) 0.2 g of iron nitrate, 0.3 g of dicyandiamide, and 2.0 g of oxalic acid were mixed and ground for 25 min, and then calcination treatment was performed under a nitrogen atmosphere to obtain Fe2O3 / C;

[0086] The calcination treatment temperature was 550°C, the time was 4 h, the nitrogen flow rate was 50 mL / min, and the heating rate was 5°C / min;

[0087] 2) 0.5 g of Fe2O3 / C was calcined with 0.042 g of selenium under an argon atmosphere to obtain Fe2O3-FeS2 / C;

[0088] Argon gas flowed from upstream to downstream, and selenium was placed upstream of the Fe2O3 / C. The argon flow rate was 20 mL / min, the calcination temperature was 350°C, the time was 1.5 h, and the heating rate was 5°C / min;

[0089] 3) 0.014 g of copper chloride and 0.031 g of cobalt acetate were ultrasonically treated with 0.5 g of Fe2O3-FeS2 / C for 20 min, and then stirred for 4 h before being dried overnight. The obtained solid was calcined with CO at a temperature of 400°C for 5 h to obtain Cu 0.4 Co 0.6 / Fe2O3-FeSe2 / C;

[0090] The catalyst Cu 0.4 Co 0.6 / Fe2O3-FeSe2 / C was reacted with cyclohexene and hydrogen peroxide at 100℃ for 6h to obtain the product.

[0091] The molar ratio of cyclohexene to hydrogen peroxide was 1:8, and the mass ratio of catalyst to cyclohexene was 1:80.

[0092] Example 4

[0093] 1) 0.2g zinc acetate, 0.36g urea and 1.2g carbon nitride were mixed and ground for 25min, and then calcination treatment was carried out under a nitrogen atmosphere to obtain ZnO / C;

[0094] The calcination treatment temperature was 600℃, the time was 6h, the nitrogen flow rate was 100mL / min, and the heating rate was 8℃ / min;

[0095] 2) 0.5g ZnO / C and 0.05g tellurium were calcined under an argon atmosphere to obtain ZnO-ZnTe / C;

[0096] The argon gas flowed from upstream to downstream, and the tellurium was placed upstream of the ZnO / C, the argon flow rate was 20mL / min, the calcination temperature was 500℃, the time was 1.5h, and the heating rate was 5℃ / min;

[0097] 3) 0.05g copper nitrate and 0.06g cobalt nitrate were co-calcined with 0.5g ZnO-ZnTe / C under the action of NH3 at a temperature of 320℃ for 3h to obtain Cu 0.5 Co 0.5 / ZnO-ZnTe / C;

[0098] 4) cyclohexene, hydrogen peroxide and the catalyst Cu 0.5 Co 0.5 / ZnO-ZnTe / C were reacted at 80℃ for 12h to obtain the product;

[0099] The molar ratio of cyclohexene to hydrogen peroxide was 1:2, and the mass ratio of catalyst to cyclohexene was 1:20.

[0100] Example 5

[0101] The catalyst preparation method of the present embodiment comprises the following steps:

[0102] 1) 0.2g nickel phosphate, 0.18g cyanamide and 1.2g starch were mixed and ground for 30min, and then calcination treatment was carried out under a nitrogen atmosphere to obtain NiO / C;

[0103] The temperature of the calcination treatment is 600°C, the time is 4h, the flow rate of nitrogen is 50mL / min, and the temperature increasing rate is 5°C / min;

[0104] 2) 0.5g of NiO / C is calcined with 0.045g of selenium under an argon atmosphere to obtain NiO-NiSe / C;

[0105] The argon gas flows from upstream to downstream, and the selenium is placed upstream of the NiO / C. The flow rate of argon is 20mL / min, the calcination temperature is 450°C, the time is 1h, and the temperature increasing rate is 3°C / min;

[0106] 3) 0.05g of copper nitrate and 0.06g of cobalt nitrate are ultrasonically treated with 0.5g of NiO-NiSe / C for 20min, and then stirred for 4h before being dried overnight. The obtained solid is calcined under the action of H2 at a temperature of 400°C for 4h to obtain Cu 0.5 Co 0.5 / NiO-NiSe / C.

[0107] The catalyst Cu 0.5 Co 0.5 / NiO-NiSe / C of the present embodiment is reacted with cyclohexene and hydrogen peroxide at 95°C for 10h to obtain a product.

[0108] The molar ratio of cyclohexene to hydrogen peroxide is 1:4, and the mass ratio of catalyst to cyclohexene is 1:50.

[0109] Example 6

[0110] The catalyst preparation method of the present embodiment includes the following steps:

[0111] 1) 0.2g of iron nitrate, 0.4g of dicyandiamide and 1.5g of cellulose are mixed and ground for 25min before being subjected to a calcination treatment under a nitrogen atmosphere to obtain Fe2O3 / C;

[0112] The temperature of the calcination treatment is 500°C, the time is 4h, the flow rate of nitrogen is 50mL / min, and the temperature increasing rate is 5°C / min;

[0113] 2) 0.5g of Fe2O3 / C is calcined with 0.05g of sulfur under an argon atmosphere to obtain Fe2O3-FeS2 / C;

[0114] The argon gas flows from upstream to downstream, and the sulfur is placed upstream of the Fe2O3 / C. The flow rate of argon is 30mL / min, the calcination temperature is 300°C, the time is 1.5h, and the temperature increasing rate is 5°C / min;

[0115] 3) 0.017 g of copper sulfate and 0.064 g of cobalt chloride were ultrasonically treated with 0.5 g of Fe2O3-FeS2 / C for 20 min, and after stirring for 4 h, the obtained solid was dried overnight, and then Cu 0.2 Co 0.8 / Fe2O3-FeS2 / C was obtained by calcining the mixture at 360°C under H2 for 4 h.

[0116] The catalyst Cu 0.2 Co 0.8 / Fe2O3-FeS2 / C of the present example was reacted with cyclohexene and hydrogen peroxide at 120°C for 4 h to obtain the product.

[0117] The molar ratio of cyclohexene to hydrogen peroxide was 1:4, and the mass ratio of the catalyst to cyclohexene was 1:80.

[0118] Example 7

[0119] The difference between the present example and Example 1 is that selenium is used instead of sulfur in step 2) to obtain ZnO-ZnSe / C.

[0120] Example 8

[0121] The difference between the present example and Example 5 is that 0.021 g of copper chloride and 0.072 g of cobalt acetate are used instead of 0.05 g of copper nitrate and 0.06 g of cobalt nitrate in step 3) to obtain Cu 0.3 Co 0.7 / NiO-NiSe / C.

[0122] Example 9

[0123] The difference between the present example and Example 3 is that 0.034 g of copper nitrate and 0.018 g of cobalt nitrate are used instead of 0.014 g of copper chloride and 0.031 g of cobalt acetate in step 3) to obtain Cu 0.7 Co 0.3 / Fe2O3-FeSe2 / C.

[0124] Example 10

[0125] The difference between the present example and Example 1 is that no cobalt nitrate is added in step 3).

[0126] Example 11:

[0127] The difference between the present example and Example 1 is that no copper nitrate is added in step 3).

[0128] Example 12

[0129] The difference between the present example and Example 1 is that 0.30 g of copper nitrate and 0.01 g of cobalt nitrate are added in step 3).

[0130] Example 13

[0131] The difference between this example and Example 1 is that in step 1), the amount of glucose added is 1.2 g.

[0132] Example 14

[0133] The difference between this example and Example 1 is that in step 1), the amount of glucose added is 0.02 g.

[0134] Example 15

[0135] The difference between this example and Example 1 is that in step 1), the amount of glucose added is 0.7 g.

[0136] Example 16

[0137] The difference between this example and Example 1 is that in step 2), 0.125 g of sulfur is added.

[0138] Example 17

[0139] The difference between this example and Example 1 is that in step 2), 0.02 g of sulfur is added.

[0140] Example 18

[0141] The difference between this example and Example 1 is that in step 2), 0.033 g of sulfur is added.

[0142] Example 19

[0143] The difference between this example and Example 1 is that in step 2), the flow rate of inert gas is 70 mL / min.

[0144] Example 20

[0145] The difference between this example and Example 1 is that zinc nitrate and glucose are directly ground and mixed, then calcined, without adding melamine.

[0146] Example 21

[0147] The difference between this example and Example 1 is that in step 3), 0.095 g of copper nitrate is added.

[0148] Comparative Example 1

[0149] The difference between the present comparative example and Example 1 is that steps 1) to 3) are not performed, and a zinc-modified titanium silicalite molecular sieve is prepared as a catalyst using the method disclosed in Patent CN102850205B, and the specific method is as follows: 6.8 g of di-zinc hydrogen phosphate is mixed with 12 g of hollow titanium silicalite molecular sieve (in the hollow titanium silicalite molecular sieve, the molar ratio of silicon atoms to titanium atoms is 130:1), and then the obtained mixture is calcined in a muffle furnace at 550°C for 5 hours in an air atmosphere, thereby obtaining catalyst K. In the catalyst K, the molar ratio of zinc atoms to titanium atoms in the hollow titanium silicalite molecular sieve is 2.5:1 in terms of elements.

[0150] Comparative Example 2

[0151] The difference between the present comparative example and Example 1 is that step 3) is not performed, and ZnO-ZnS / C is directly used as a catalyst.

[0152] Comparative Example 3

[0153] The difference between the present comparative example and Example 1 is that step 2) is not performed, and copper nitrate and cobalt nitrate solution are calcined together with ZnO / C to obtain catalyst Cu 0.5 Co 0.5 / ZnO / C.

[0154] Comparative Example 4

[0155] The difference between the present comparative example and Example 1 is that in step 2), ZnO / C obtained in step 1) is mixed with excess elemental sulfur in a porcelain boat and calcined to convert ZnO into ZnS completely, thereby obtaining catalyst Cu 0.5 Co 0.5 / ZnS / C:

[0156] Comparative Example 5

[0157] The difference between the present comparative example and Example 1 is that in step 3), 0.013 g of copper and 0.012 g of cobalt are directly mixed with 0.5 g of ZnO-ZnS / C to obtain a catalyst, and the copper and cobalt are not loaded on the ZnO-ZnS / C.

[0158] Test Example 1

[0159] The present application uses gas chromatography and liquid chromatography to analyze the content of each component in the product of catalytic oxidation of cyclohexene, and then calculates the conversion rate of cyclohexene and the selectivity of adipic acid by the following formula, and the results are shown in Table 1:

[0160] Cyclohexene conversion rate % = (moles of added cyclohexene - moles of cyclohexene in product) / moles of added cyclohexene x 100%;

[0161] Adipic acid selectivity % = moles of adipic acid in product / (moles of added cyclohexene - moles of cyclohexene in product) x 100%.

[0162] Table 1

[0163]

[0164]

[0165] According to the data in Table 1, the catalyst of the present application can successfully convert cyclohexene into adipic acid, has high cyclohexene conversion rate and adipic acid selectivity, and does not need to use toxic or corrosive substances such as phase transfer agent, nitric acid, etc., which is safe and environmentally friendly. As can be seen from the comparative examples, when not using the catalyst of the present application for catalysis, the cyclohexene conversion rate and adipic acid selectivity are significantly reduced.

[0166] In order to make the objects, technical solutions and advantages of the present application clearer, the above technical solutions of the present application are described clearly and completely in combination with specific examples. Obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A catalyst for the oxidation of cyclohexene to prepare adipic acid, characterized in that, Includes a support and copper and / or cobalt loaded on the support; the support includes a carbon matrix and a first support compound and a second support compound loaded on the carbon matrix; The first support compound includes at least one of NiO, ZnO, and Fe2O3; the second support compound includes at least one of ZnX, NiX, and FeX2, where X is selected from at least one of S, Se, and Te. The method for preparing the catalyst includes the following steps: subjecting a reaction system comprising copper salt and / or cobalt salt, a support and a reducing agent to a reduction reaction to obtain the catalyst; The carrier is prepared by a method comprising the following steps: 1) A mixture comprising a first metal source, an organic carbon source, and a nitrogen source is calcined, wherein the nitrogen source reduces the organic carbon source to carbon bulk, and the first metal source is oxidized to a first support compound, thereby obtaining a nitrogen-doped carbon bulk loaded with the first support compound. 2) The chalcogenide element and the nitrogen-doped carbon matrix loaded with the first support compound are co-calcined to obtain the support; The nitrogen source is selected from melamine, urea, dicyandiamide, or cyanamide; The oxalic elements are selected from at least one of sulfur, selenium, and tellurium.

2. A method for preparing the catalyst according to claim 1, characterized in that, The process includes the following steps: reducing a reaction system comprising copper salts and / or cobalt salts, a support, and a reducing agent to obtain the catalyst; The carrier is prepared by a method comprising the following steps: 1) A mixture comprising a first metal source, an organic carbon source, and a nitrogen source is calcined, wherein the nitrogen source reduces the organic carbon source to carbon bulk, and the first metal source is oxidized to a first support compound, thereby obtaining a nitrogen-doped carbon bulk loaded with the first support compound. 2) The chalcogenide element and the nitrogen-doped carbon matrix loaded with the first support compound are co-calcined to obtain the support; The nitrogen source is selected from melamine, urea, dicyandiamide, or cyanamide; The oxalic elements are selected from at least one of sulfur, selenium, and tellurium.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the copper salt and / or cobalt salt to the carrier is 1:(10~100).

4. The preparation method according to claim 2, characterized in that, The molar ratio of the metal element in the first metal source to the carbon element in the organic carbon source and the nitrogen element in the nitrogen source is 1:(4~50):(0.5~4).

5. The preparation method according to claim 2 or 4, characterized in that, The mass ratio of the oxalic element to the nitrogen-doped carbon matrix supporting the first carrier compound is 1:(5~20).

6. The preparation method according to claim 2, characterized in that, The co-calcination in step 2) is carried out in an inert gas atmosphere, with the inert gas flowing from upstream to downstream. The oxalic element is placed upstream of the nitrogen-doped carbon matrix loaded with the first carrier compound. The flow rate of the inert gas is 20~50 mL / min, the calcination temperature is 300~500℃, and the time is 0.5~2h.

7. A method for preparing adipic acid by oxidizing cyclohexene, characterized in that, The process includes the following steps: using the catalyst described in claim 1, or the catalyst prepared by any one of claims 2-6, to cause an oxidation reaction in a system comprising cyclohexene and an oxidant to obtain adipic acid.

8. The method according to claim 7, characterized in that, The oxidant is an aqueous solution of hydrogen peroxide, and the oxidation reaction temperature is 60~120℃; the molar ratio of cyclohexene to hydrogen peroxide is 1:(2~15); the mass ratio of the catalyst to cyclohexene is 1:(5~200).

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