A cobalt-based perovskite oxide catalyst and its preparation and application

Abstract

The present invention discloses a cobalt-based perovskite oxide catalyst and its preparation and application. The cobalt-based perovskite oxide of the present invention can regulate its metal element composition, crystal structure, metal element valence state and oxygen vacancy concentration by extensive doping of A-position and B-position, and can also regulate the composition, surface element chemical state, surface defect type and concentration of its surface catalytic active center by surface interface modification treatment of the oxide. The cobalt-based perovskite oxide catalyst prepared by the present invention can be used for one-step cyclohexane catalytic oxidation reaction, and highly selectively prepares cyclohexanol and cyclohexanone (commonly known as KA oil). The cobalt-based perovskite oxide catalyst prepared by the present invention can not only activate the reaction substrate, but also promote the rapid decomposition and conversion of the reaction intermediate, and the different metal ions in the catalyst have good synergistic catalytic effect, greatly improve the reaction process efficiency and KA oil yield, show good alkane partial oxidation catalytic performance, and the catalyst is easy to separate and has good stability, and is an environmentally friendly heterogeneous catalyst with industrial application prospects.

Description

Technical Field

[0001] The present invention relates to a cobalt-based perovskite oxide catalyst and its preparation and application, and in particular to the application of the cobalt-based perovskite oxide catalyst in the selective catalytic oxidation of hydrocarbon compounds to prepare high value-added compounds. Background Art

[0002] The mixture of cyclohexanone and cyclohexanol is commonly known as KA oil. Cyclohexanone, an organic compound, is a saturated cyclic ketone with a carbonyl carbon atom included in a six-membered ring. It is a colorless, transparent liquid with a molecular formula of C6H 10 O, molecular weight is 98.14, melting point is -47°C, boiling point is 155°C. Cyclohexanol is an organic compound with the chemical formula C6H 12 O, a colorless viscous liquid at room temperature and pressure, with a molecular weight of 100.158, a melting point of 25.93°C, and a boiling point of 161.84°C. KA oil is widely used in the fields of pesticides, medicines, coatings, detergents, etc., and is also an important intermediate for the production of nylon-6 and nylon-66. There have been many reports on the method of producing KA oil. At present, the industry mainly adopts a two-step method to produce KA oil, that is, cyclohexane is first oxidized to obtain cyclohexyl hydroperoxide, and then the cyclohexyl hydroperoxide is decomposed under alkaline conditions to obtain KA oil. For the two-step method for preparing KA oil, the cyclohexane oxidation reaction temperature is 160-170°C, the cyclohexane single-pass conversion rate is low (3-5%), and the total yield of KA oil is not high (81-83%), resulting in low efficiency and high energy consumption in the production process, and a large amount of saponification waste alkali liquor is generated, which seriously pollutes the environment. Therefore, it is urgent to develop a green and efficient catalyst for the one-step catalytic oxidation of cyclohexane to prepare KA oil, so as to improve the efficiency of the production process and promote the sustainable development of the industry.

[0003] Patent US4326084 reports a two-step method for preparing KA oil using a soluble cobalt salt as a homogeneous catalyst. First, cyclohexane is oxidized to generate a mixture containing cyclohexyl hydroperoxide; then, cyclohexyl hydroperoxide is decomposed into KA oil at a temperature of 151-154°C. This method is a homogeneous catalytic process, the catalyst is easily fouled, and a two-step reaction process is required to obtain KA oil. In order to obtain a higher KA oil yield, the conversion rate of cyclohexane needs to be controlled below 4%, and the maximum decomposition rate of cyclohexyl hydroperoxide is 97%.

[0004] Patent JP2000239210A2 (2000) uses N-hydroxyphthalimide (NHPI) and a mixture of cobalt acetylacetonate as a homogeneous catalyst to directly oxidize cyclohexane to KA oil. The cyclohexane oxidation reaction temperature of the invention is 160°C, the reaction pressure is 4.0 MPa, the reaction time is 2 hours, the cyclohexane conversion rate is 11%, and the KA oil selectivity is 89%. Although the technology has a high substrate conversion rate and KA oil selectivity, the amount of catalyst added during the reaction is large (the mass of cobalt acetylacetonate accounts for about 6.8% of cyclohexane, and the amount of NHPI accounts for about 17% of cyclohexane), the catalyst cost is high, the reaction pressure is also high, the catalyst stability is poor, and it is difficult to recover, which is not conducive to industrial application.

[0005] Patent CN 109331859A reports that a carbon nitride-supported cobalt tetroxide catalyst is used for cyclohexane oxidation reaction. Under the conditions of reaction temperature of 150°C, reaction pressure of 0.8 MPa and reaction time of 1.5 h, the conversion rate of cyclohexane is 7.43% and the selectivity of KA oil is 82.41%.

[0006] Patent US7045667B2 reported that a cerium-zirconium composite oxide catalyst prepared by a common coprecipitation method was used for cyclohexane oxidation reaction. Under the conditions of reaction temperature of 120°C, air pressure of 1.1 MPa, and reaction time of 5 h, the conversion rate of cyclohexane was about 1.4%, and the selectivity of KA oil was about 75%. The activity and selectivity of the catalyst were relatively low.

[0007] Patent WO99 / 40055 (1999) and patent US006160183A (2000) reported that a catalyst containing precious metal gold was prepared by a general sol-gel method, and the conversion rate of cyclohexane was 4.7% and the total selectivity of KA oil and cyclohexyl hydroperoxide was 86.2% at 170° C. The catalyst used precious metal gold, the catalyst preparation cost was high, and the activity and selectivity of the catalyst were not ideal.

[0008] Lu, H. and Dai, S. et al. studied the manganese-cerium solid solution catalyst prepared by adding ionic liquid complexation method, and applied the manganese-cerium solid solution catalyst to the selective oxidation reaction of cyclohexane at a lower temperature (Nature Communications, 2015, 6: 1-10). 0.5 Ce 0.5 O xThe solid solution is used as a catalyst, acetonitrile is used as a solvent, the reaction temperature is 100°C, the oxygen pressure is 1MPa, the reaction time is 12h, the conversion rate of cyclohexane is 17.7%, and the selectivity of KA oil is 81%. The catalyst preparation process of this method is complicated, and toxic ionic liquids are used as complexing agents and template agents; a large amount of acetonitrile solvent (about three times the volume of cyclohexane) is required in the reaction process, which increases the difficulty of post-processing and causes great environmental pollution.

[0009] The present invention provides a method for preparing a cobalt-based perovskite oxide catalyst, which is used for one-step cyclohexane catalytic oxidation to prepare KA oil with high selectivity. The cobalt-based perovskite oxide catalyst in the present invention can not only activate the reaction substrate, but also promote the rapid decomposition and conversion of the reaction intermediate cyclohexyl hydroperoxide. The reaction product does not contain or contains only a trace amount of cyclohexyl hydroperoxide, so a subsequent peroxide decomposition process is not required. Different metal ions in the catalyst have a good synergistic catalytic effect, which greatly improves the reaction process efficiency and KA oil yield, and shows good alkane partial oxidation catalytic performance. The catalyst is easy to separate and has good stability, and is an environmentally friendly heterogeneous catalyst with industrial application prospects. Summary of the invention

[0010] The present invention aims to provide a cobalt-based perovskite oxide (La x A 1-x Co y B 1-y O 3-δ ) catalyst and its preparation and application in the one-step catalytic oxidation of cyclohexane to prepare KA oil with high selectivity. The method for preparing the cobalt-based perovskite oxide catalyst is characterized in that a quantitative amount of a cobalt-containing salt compound, a lanthanum-containing salt compound and a salt modifier containing other metal ions are dissolved in water, and then a complexing agent is added under the action of a gravity field, ultrasound, microwave or magnetic field to carry out a complexing reaction, and the obtained complex is evaporated and dried to obtain a gel, which is then calcined in an oxygen-containing atmosphere to obtain a cobalt-based perovskite oxide catalyst. The cobalt-based perovskite oxide catalyst is used for the one-step partial catalytic oxidation of cyclohexane to prepare KA oil, and the conversion rate of cyclohexane can reach more than 7.6%, and the selectivity of KA oil can reach more than 89%. The cobalt-based perovskite oxide catalyst prepared by the present invention can not only activate the reaction substrate, but also promote the rapid conversion of the reaction intermediates. The reaction product contains no or only a trace amount of cyclohexyl hydroperoxide, so no subsequent peroxide decomposition process is required. The different metal ions in the catalyst have a good synergistic catalytic effect, which greatly improves the reaction process efficiency and KA oil yield, and shows good alkane partial oxidation catalytic performance. The catalyst is easy to separate and has good stability. It is an environmentally friendly heterogeneous catalyst with industrial application prospects.

[0011] According to the present invention, a cobalt-based perovskite oxide catalyst and its preparation and application are provided, characterized in that the chemical formula of the cobalt-based perovskite oxide catalyst is La x A 1-x Co y B 1-y O 3-δ (x=0-1, y=0-1, δ=0-1), the preparation process of the catalyst comprises the following steps:

[0012] (1) Weigh a certain amount of a salt compound containing cobalt as a cobalt source, weigh a certain amount of a salt compound containing lanthanum as a lanthanum source, and weigh a certain amount of a salt compound containing other metal ions as a modifier, add a certain amount of deionized water until the weighed salt is completely dissolved to obtain a solution A, add a certain amount of a complexing agent to the solution A, and carry out a complexing reaction at a temperature of 20-90° C. in one or more external fields of gravity, ultrasound, microwave or magnetic field, so that the cobalt ions and lanthanum ions in the solution A form a stable and uniform complex with the complexing agent.

[0013] (2) Under constant temperature conditions, solution A is stirred and slowly evaporated, and the temperature is controlled between 50-100° C. to evaporate and remove excess water. The resulting gel is dried and calcined in an oxygen-containing atmosphere at a calcination temperature of 200-900° C. (preferably 300-800° C., and more preferably 500-800° C.) to obtain cobalt-based perovskite oxide catalysts having different compositions and different cobalt valence states.

[0014] (3) The cobalt-based perovskite oxide catalyst prepared in step (2) is subjected to surface modification treatment, specifically: soaking treatment with an acid solution or an alkaline solution to selectively dissolve the surface metal oxygen ions and form surface anion and cation defects, then washing with deionized water, and then drying and calcining treatment, the calcination temperature is 200-900°C (preferably 300-800°C, more preferably 500-800°C); or treating with water vapor for 0.1-12h (preferably 0.5-6h), and then drying treatment at 60-80°C for 0.5-24h (preferably 3-12h). Through different surface modification methods, La x A 1-x Co y B 1-y O 3-δ The surface oxygen vacancy concentration of the catalyst is controlled within the range of δ = 0.01-0.6 (preferably δ = 0.05-0.3), and the molar defect concentration of the cation is controlled within the range of 0-0.2 mol / mol La x A 1-x Co y B 1-y O 3-δ Within this range, surface-modified cobalt-based perovskite oxide catalysts were obtained.

[0015] The above-mentioned catalyst preparation method uses cobalt-based perovskite oxide as the active material, has a simple synthesis method, and the elemental composition of the A and B positions can be adjusted. The method for surface modification is relatively simple and convenient for large-scale synthesis. The cobalt-based perovskite oxide also has good catalytic activity in cyclohexane oxidation at a relatively low temperature.

[0016] Furthermore, in step (1), the cobalt salt compound is a +2-valent or +3-valent cobalt salt, preferably one or more of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt dichloride or cobalt trichloride; the lanthanum salt compound is a +3-valent lanthanum salt, preferably one or more of lanthanum acetate, lanthanum sulfate, lanthanum carbonate, lanthanum chloride, lanthanum nitrate, lanthanum cerium nitrate, etc.

[0017] Furthermore, in step (1), the salt compound modifier containing other metal ions is used for cobalt-based perovskite oxide La x A 1-x Co y B 1-y O 3-δ The A-position and B-position doping modification, the A-position modified metal ion is one or more of rare earth metal, main group metal, alkali metal or alkaline earth metal La, Nd, Sm, Gd, Dy, Y, Ce, Bi, Li, Na, K, Mg, Ca, Sr, Ba ions, the B-position modified metal ion is one or more of transition metal or main group metal Fe, Mn, Cu, Zn, Ni, Mg, V, W, Mo, Zr, Ti, Ce, Cr, Y, Sm, Sc, Hf, Pt, Ir, Ru, Rh, Pd, Al, Bi, Si, Ga ions, the salt compound modifier is one or more of sulfate, nitrate, acetate, carbonate, chloride. The La x A 1-x Co y B 1-y O 3-δ In the catalyst, the molar content of metallic lanthanum is x=0-1, and the total molar content of other rare earth metals, main group metals, alkali metals or alkaline earth metals is 1-x, preferably x=0-0.5; the molar content of metallic cobalt is y=0.01-1, and the total molar content of other transition metals or main group metals is 1-y, preferably y=0.01-0.5.

[0018] Furthermore, in step (1), the complexing agent is one or more of citric acid, tartaric acid, glycine, oxalic acid, ethylenediaminetetraacetic acid, sodium hexametaphosphate, ethanolamine, polyacrylic acid, etc., and the amount of the complexing agent is based on the total molar amount of all metal elements, and the molar amount of the complexing agent to the molar amount of all metal elements is 1.0-6.0, preferably 1.5-4.0, and more preferably 2.0-3.5.

[0019] Furthermore, in step (2) and step (3), the calcination treatment refers to placing the catalyst in a muffle furnace or an atmosphere furnace, heating the temperature to 200-900°C at a heating rate of 5-20°C / min, keeping the temperature for 1-6 hours, cooling to room temperature and collecting for later use. The atmosphere introduced into the atmosphere furnace is air or a mixed gas of oxygen and nitrogen (the volume ratio of oxygen / nitrogen is: O2 / N2=0-1), and the gas flow rate is 20-400mL min -1 .

[0020] Furthermore, in step (3), the acid solution is capable of hydrolyzing or dissociating H + The acid solution is preferably one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, tartaric acid, sodium bisulfate, oxalic acid, and acetic acid; the alkaline solution is one or more of sodium hydroxide solution, sodium carbonate, ammonium chloride solution, and ammonium bisulfate; the concentration of the acid solution or the alkaline solution is 0.01-3 mol / L (preferably 0.01-1 mol / L); the immersion treatment temperature is 10-80°C (preferably 25-60°C); and the immersion treatment time is 0.1-12h (preferably 0.5-3h).

[0021] The catalyst obtained by the above preparation method is used for the selective catalytic oxidation of hydrocarbons, preferably for the catalytic oxidation of cyclohexane.

[0022] Furthermore, the catalytic oxidation of cyclohexane is a one-step oxidation of cyclohexane to produce KA oil, specifically: under the action of a perovskite oxide catalyst, cyclohexane is subjected to a catalytic oxidation reaction with air or oxygen-enriched air or oxygen, and the product contains no or only a trace amount of cyclohexyl hydroperoxide, so there is no need for a subsequent decomposition step of cyclohexyl hydroperoxide.

[0023] Furthermore, the temperature of the catalytic oxidation reaction is 100-200°C, preferably 130-160°C; the reaction pressure is 0.1-2MPa, preferably 0.4-1.0Mpa; the reaction time is 0.2-6h, preferably 0.5-1h; and the amount of catalyst added is 0.01-3% of the mass of cyclohexane, preferably 0.01-1%.

[0024] The beneficial effects of the present invention are:

[0025] The cobalt-based perovskite oxide catalyst prepared by the present invention has good stability, and the A-position and B-position elements of the perovskite oxide have a certain tolerance for most metal elements in the periodic table, and most elements can be widely doped and modified, and its composition, crystal structure, metal element valence state and oxygen vacancy concentration are easy to adjust. The composition and chemical state of the surface catalytic active center, the surface defect type and its concentration can be effectively regulated by simple acid solution or alkaline solution soaking treatment. The different metal ions in the catalyst have good synergistic catalytic effect, greatly improve the reaction process efficiency and KA oil yield, and show good alkane partial oxidation catalytic performance. The cobalt-based perovskite oxide catalyst prepared by the present invention is applied to the one-step cyclohexane catalytic oxidation to prepare KA oil, and the conversion rate of cyclohexane can reach more than 7.6%, and the selectivity of KA oil can reach more than 89%. The catalytic performance is better than the existing industrial level, and the reaction conditions are mild, and no organic solvent is required. The cobalt-based perovskite oxide catalyst prepared by the present invention has stable performance, is easy to separate and reuse, is environmentally friendly, and has potential industrial application value. In addition, the cobalt-based perovskite oxide catalyst prepared by the present invention can also be applied to the selective catalytic oxidation reaction of other hydrocarbons to prepare high value-added compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The following are X-ray diffraction (XRD) diagrams of catalysts prepared under different conditions of the present invention. DETAILED DESCRIPTION

[0027] The following examples are used to describe the technical solution of the present invention in detail. The following examples are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention. An intermittent process is described in the examples.

[0028] Preparation Examples 1-15 are used to illustrate the perovskite oxide catalyst and the preparation method thereof of the present invention.

[0029] Preparation Example 1: Preparation of lanthanum cobaltate perovskite oxide catalyst: Weigh 4.3g of lanthanum nitrate hexahydrate and 2.9g of cobalt nitrate hexahydrate respectively, then add 80ml of deionized water, stir to completely dissolve, then weigh 2.0g of glycine and add it to the solution, then mix the solution thoroughly under ultrasonic conditions to carry out complexation reaction. Then, stir and evaporate the solution in a 90°C oil bath to a gel state, and then calcine in a muffle furnace at 800°C for 4 hours to obtain lanthanum cobaltate perovskite oxide catalyst C1.

[0030] Preparation Example 2: The preparation method of calcium cobaltate oxide catalyst is the same as that of Preparation Example 1, except that 4.3 g of lanthanum nitrate hexahydrate is replaced by 2.4 g of calcium nitrate tetrahydrate, and 2.0 g of glycine is replaced by 1.5 g, to obtain calcium cobaltate oxide catalyst C2.

[0031] Preparation Example 3: The preparation method of manganese-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that half of the 2.9 g of cobalt nitrate hexahydrate is replaced with 1.8 g of a 50% manganese nitrate solution to obtain a manganese-modified lanthanum cobaltate perovskite oxide catalyst C3.

[0032] Preparation Example 4: The preparation method of the strontium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that half of the 4.3 g lanthanum nitrate hexahydrate is replaced with 1.0 g strontium nitrate, and 2.0 g of glycine is replaced with 1.8 g to obtain a strontium-modified lanthanum cobaltate perovskite oxide catalyst C4.

[0033] Preparation Example 5: The preparation method of the calcium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that half of the 4.3 g lanthanum nitrate hexahydrate is replaced with 1.2 g calcium nitrate tetrahydrate, and 2.0 g of glycine is replaced with 1.8 g to obtain a calcium-modified lanthanum cobaltate perovskite oxide catalyst C5.

[0034] Preparation Example 6: The preparation method of calcium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that 4.3 g of lanthanum nitrate hexahydrate is replaced by 0.4 g of lanthanum nitrate hexahydrate and 2.2 g of calcium nitrate tetrahydrate, and 2.0 g of glycine is replaced by 1.6 g to obtain calcium-modified lanthanum cobaltate perovskite oxide catalyst C6.

[0035] Preparation Example 7: The preparation method of the calcium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that 4.3 g of lanthanum nitrate hexahydrate is replaced by 1.3 g of lanthanum nitrate hexahydrate and 1.7 g of calcium nitrate tetrahydrate, and 2.0 g of glycine is replaced by 1.7 g to obtain a calcium-modified lanthanum cobaltate perovskite oxide catalyst C7.

[0036] Preparation Example 8: The preparation method of calcium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 1, except that 4.3 g of lanthanum nitrate hexahydrate is replaced by 3.0 g of lanthanum nitrate hexahydrate and 0.7 g of calcium nitrate tetrahydrate, and 2.0 g of glycine is replaced by 1.9 g to obtain calcium-modified lanthanum cobaltate perovskite oxide catalyst C8.

[0037] Preparation Example 9: The preparation method of calcium-doped modified lanthanum cobaltate perovskite oxide catalyst is the same as that of Preparation Example 5, except that the gel is calcined at 600° C. in a muffle furnace for 4 h to obtain a calcium-modified lanthanum cobaltate perovskite oxide catalyst C9.

[0038] Preparation Example 10: Weigh 1.0 g of oxalic acid dihydrate and add it to 100 mL of deionized water, stir and dissolve, weigh 0.5 g of calcium-doped lanthanum cobaltate calcium oxide catalyst C5 synthesized by the method of Preparation Example 5 and add it to the prepared oxalic acid solution for 12 hours, wash it with water and ethanol alternately for 3 times, put it in a 60°C oven to dry, and then put it in a muffle furnace for calcination at 550°C for 3 hours. The calcium-doped lanthanum cobaltate perovskite oxide catalyst C10 with oxalic acid surface modification was obtained.

[0039] Preparation Example 11: Chloride ion-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst The preparation method is the same as that of Preparation Example 10, except that 1.0 g of oxalic acid dihydrate is added to 100 mL of deionized water and replaced with 0.3 g of ammonium chloride dissolved in 50 mL of deionized water. The chloride ion surface-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C11 is obtained.

[0040] Preparation Example 12: Calcium-doped lanthanum cobaltate perovskite oxide catalyst modified by citric acid The preparation method is the same as that of Preparation Example 10, except that 1.0 g of oxalic acid dihydrate added to 100 mL of deionized water is replaced by 6.3 g of citric acid dissolved in 30 mL of deionized water, and the immersion time is replaced by 2 h. The citric acid surface-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C12 is obtained.

[0041] Preparation Example 13: Hydrochloric acid-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst The preparation method is the same as that of Preparation Example 10, except that 1.0 g of oxalic acid dihydrate is added to 100 mL of deionized water and replaced with 50 mL of 0.02 mol / L dilute hydrochloric acid, and the immersion time is replaced with 2 h. The hydrochloric acid surface-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C13 is obtained.

[0042] Preparation Example 14: Nitric Acid-Modified Calcium-Doped Lanthanum Cobaltate Perovskite Oxide Catalyst The preparation method is the same as that of Preparation Example 10, except that 1.0 g of oxalic acid dihydrate is added to 100 mL of deionized water and replaced with 100 mL of 0.04 mol / L dilute nitric acid, and the immersion is replaced with 2 h. The nitric acid-surface-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C14 is obtained.

[0043] Preparation Example 15: Weigh 0.5 g of the calcium-doped lanthanum cobaltate calcium oxide catalyst C5 synthesized using the method of Preparation Example 5, place it in a water vapor atmosphere for 6 hours, and then place it in a 60°C oven to dry, to obtain a hydroxyl surface-modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C15.

[0044] Preparation Example 16: Calcium-doped modified lanthanum cobaltate perovskite oxide catalyst The preparation method is the same as that of Preparation Example 5, except that the mixed solution is placed under microwave conditions for complexation reaction, thereby obtaining microwave-assisted modified calcium-doped lanthanum cobaltate perovskite oxide catalyst C16.

[0045] Examples 1-26 are used to illustrate the experimental method for catalytic oxidation of cyclohexane according to the present invention.

[0046] Example 1: Weigh 60g of cyclohexane and 0.1g of lanthanum cobaltate perovskite oxide C1 obtained in Preparation Example 1 and place them in a 250ml autoclave reactor, turn on the heating and stirring, and when the temperature approaches 120°C, start to introduce oxygen to reach 0.9Mpa (gauge pressure). When the temperature rises to 130°C, adjust the oxygen pressure to 1.0Mpa (gauge pressure) to reach a reaction pressure of 1.0Mpa (gauge pressure), and maintain the pressure at 1.0Mpa (gauge pressure) during the reaction. When the temperature rises to 130°C, start the reaction timing and react for 3 hours. After the reaction is completed, cool the reactor to room temperature. Separate the catalyst from the liquid product by centrifugation. The liquid product KA oil is quantitatively analyzed by gas chromatography internal standard method (with chlorobenzene as internal standard), and the liquid product acid and ester are quantitatively analyzed by acid-base titration. The conversion rate of cyclohexane is 5.4%, and the selectivity of KA oil is 80.3%.

[0047] Example 2: The reaction steps are the same as those of Example 1, except that the catalyst used is the calcium cobalt oxide catalyst C2 prepared in Preparation Example 2, and the conversion rate of cyclohexane is 2.8%, and the selectivity of KA oil is 77.6%.

[0048] Example 3: The reaction steps are the same as those of Example 1, except that the catalyst used is the manganese-modified lanthanum cobaltate perovskite oxide catalyst C3 prepared in Preparation Example 3, and the conversion rate of cyclohexane is 4.3%, and the selectivity of KA oil is 75.2%.

[0049] Example 4: The reaction steps are the same as those of Example 1, except that the catalyst is the strontium-modified lanthanum cobaltate perovskite oxide catalyst C4 prepared in Preparation Example 4, and the conversion rate of cyclohexane is 4.2%, and the selectivity of KA oil is 78.5%.

[0050] Example 5: The reaction steps are the same as those of Example 1, except that the catalyst is the calcium-modified lanthanum cobaltate perovskite oxide catalyst C5 prepared in Preparation Example 5, and the conversion rate of cyclohexane is 5.8%, and the selectivity of KA oil is 83.3%.

[0051] Example 6: Weigh 60g of cyclohexane and 0.1g of lanthanum cobaltate calcium perovskite oxide C5 obtained in Preparation Example 5 and place them in a 250ml autoclave reactor, turn on the heating and stirring, and when the temperature approaches 130°C, start to introduce oxygen to reach 0.55MPa. When the temperature rises to 150°C, adjust the oxygen pressure to 0.65MPa to reach a reaction pressure of 0.65MPa, and maintain the pressure at 0.65MPa during the reaction. When the temperature rises to 150°C, start the reaction timing and react for 2 hours. After the reaction is completed, cool the reactor to room temperature. Separate the catalyst from the liquid product by centrifugation. The liquid product KA oil is quantitatively analyzed by gas chromatography internal standard method (with chlorobenzene as internal standard), and the liquid product acid and ester are quantitatively analyzed by acid-base titration. The conversion rate of cyclohexane is 7.7%, and the selectivity of KA oil is 86.4%.

[0052] Example 7: The reaction steps are the same as those of Example 6, except that the reaction time is 1 h, the conversion rate of cyclohexane is 6.0%, and the selectivity of KA oil is 81.6%.

[0053] Example 8: The reaction steps are the same as those of Example 6, except that the reaction time is 3 h, the conversion rate of cyclohexane is 8.7%, and the selectivity of KA oil is 81.0%.

[0054] Example 9: The reaction steps are the same as those of Example 6, except that the reaction temperature is 130°C, the conversion rate of cyclohexane is 4.3%, and the selectivity of KA oil is 73.2%.

[0055] Example 10: The reaction steps are the same as those of Example 6, except that the reaction temperature is 140°C, the conversion rate of cyclohexane is 11.5%, and the selectivity of KA oil is 75.9%.

[0056] Example 11: The reaction steps are the same as those of Example 6, except that the reaction temperature is 160°C, the conversion rate of cyclohexane is 5.7%, and the selectivity of KA oil is 83.7%.

[0057] Example 12: The reaction steps are the same as those of Example 6, except that the reaction pressure is 0.5 MPa, the conversion rate of cyclohexane is 4.4%, and the selectivity of KA oil is 87.0%.

[0058] Example 13: The reaction steps are the same as those of Example 6, except that the reaction pressure is 0.6 MPa, the conversion rate of cyclohexane is 6.9%, and the selectivity of KA oil is 85.3%.

[0059] Example 14: The reaction steps are the same as those of Example 6, except that the reaction pressure is 0.7 MPa, the conversion rate of cyclohexane is 10.7%, and the selectivity of KA oil is 77.3%.

[0060] Example 15: The reaction steps are the same as those of Example 13, except that the catalyst used is calcium cobaltate oxide catalyst C2, the conversion rate of cyclohexane is 6.7%, and the selectivity of KA oil is 84.8%.

[0061] Example 16: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C6, and the conversion rate of cyclohexane obtained is 6.7%, and the selectivity of KA oil is 80.6%.

[0062] Example 17: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C7, and the conversion rate of cyclohexane obtained is 6.6%, and the selectivity of KA oil is 81.3%.

[0063] Example 18: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C8, and the conversion rate of cyclohexane obtained is 6.7%, and the selectivity of KA oil is 81.1%.

[0064] Example 19: The reaction steps are the same as those of Example 13, except that the catalyst used is lanthanum cobaltate perovskite oxide catalyst C1, the conversion rate of cyclohexane is 6.6%, and the selectivity of KA oil is 85.0%.

[0065] Example 20: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C9, and the conversion rate of cyclohexane obtained is 7.4%, and the selectivity of KA oil is 74.6%.

[0066] Example 21: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C10, and the conversion rate of cyclohexane obtained is 6.9%, and the selectivity of KA oil is 82.2%.

[0067] Example 22: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C11, and the conversion rate of cyclohexane obtained is 7.0%, and the selectivity of KA oil is 77.6%.

[0068] Example 23: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C12, and the conversion rate of cyclohexane obtained is 6.7%, and the selectivity of KA oil is 85.4%.

[0069] Example 24: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C13, and the conversion rate of cyclohexane obtained is 6.6%, and the selectivity of KA oil is 86.7%.

[0070] Example 25: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C14, and the conversion rate of cyclohexane obtained is 6.0%, and the selectivity of KA oil is 81.3%.

[0071] Example 26: The reaction steps are the same as those of Example 13, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C15, and the conversion rate of cyclohexane is 7.2%, and the selectivity of KA oil is 85.3%.

[0072] Example 27: The reaction steps are the same as those of Example 6, except that the catalyst used is a calcium-modified lanthanum cobaltate perovskite oxide catalyst C16, and the conversion rate of cyclohexane is 7.6%, and the selectivity of KA oil is 89.6%.

[0073] Comparative Example 1: The reaction steps are the same as those of Example 1, except that the catalyst used is Co3O4, the conversion rate of cyclohexane is 1.7%, and the selectivity of KA oil is 57.3%.

[0074] Comparative Example 2: The reaction steps are the same as those of Example 1, except that the catalyst used is MnO2, the conversion rate of cyclohexane is 1.9%, and the selectivity of KA oil is 73.5%.

[0075] Comparative Example 3: The reaction steps are the same as those of Example 1, except that no catalyst is used, the conversion rate of cyclohexane is 0.2%, and the selectivity of KA oil is 35.8%.

[0076] The cyclohexane catalytic oxidation performance results of different catalysts are shown in Table 1 below.

[0077] Table 1 Cyclohexane catalytic oxidation performance results of different catalysts

[0078]

[0079] a The reaction pressure is gauge pressure.

Claims

1. Use of a cobalt-based perovskite oxide catalyst in the partial catalytic oxidation of cyclohexane to prepare cyclohexanol and cyclohexanone, characterized in that: The chemical formula of the cobalt-based perovskite oxide catalyst is La x A 1-x Co y B 1-y O 3-δ , x=0-1, y=0-1, δ=0.01-0.6, wherein the value of y is not 0, the A position and B position of the cobalt-based perovskite oxide are doped and modified with different metal ions, the A position modified metal ion is one or more of Nd, Sm, Gd, Dy, Y, Ce, Mg, Ca, Sr, Ba ions, and the B position modified metal ion is one or more of Fe, Mn, Cu, Zn, Ni, Mg, V, W, Mo, Zr, Ti, Ce, Cr, Y, Sm, Sc, Hf, Al, Bi, Ga ions, and the preparation of the catalyst comprises the following steps: (1) weighing a certain amount of a salt compound containing cobalt as a cobalt source, weighing a certain amount of a salt compound containing lanthanum as a lanthanum source, and weighing a certain amount of a salt compound containing other metal ions as a modifier, adding a certain amount of deionized water until the weighed salt is completely dissolved to obtain a solution A, and adding a certain amount of a complexing agent to the solution A; performing a complexing reaction at a temperature of 20-90° C. in one or more external field environments of a gravity field, an ultrasonic wave, a microwave or a magnetic field, so that the cobalt ions and the lanthanum ions in the solution A form a stable and uniform complex with the complexing agent; (2) stirring solution A to evaporate slowly under constant temperature conditions, wherein the evaporation temperature is controlled between 50° C. and 100° C., and excess water is evaporated away, and the obtained gel is dried and calcined in an oxygen-containing atmosphere at a calcination temperature of 200° C. and 900° C., to obtain cobalt-based perovskite oxide catalysts having different compositions and different cobalt valence states; (3) subjecting the cobalt-based perovskite oxide catalyst prepared in step (2) to surface modification treatment, specifically: soaking in an acid solution or an alkaline solution to selectively dissolve surface metal cations and form surface anion and cation defects, washing with deionized water, and then drying and calcining at a calcination temperature of 200-900° C.; or treating with water vapor for 0.1-12 h, and then drying at 60-80° C. for 0.5-24 h; using different surface modification methods, La x A 1-x Co y B 1-y O 3-δ The surface oxygen vacancy concentration of the catalyst is controlled in the range of δ = 0.01-0.6, and the molar defect concentration of the cation is controlled in the range of 0-0.2 mol / mol La x A 1-x Co y B 1-y O 3-δ In the range of 0.1% to 0.2%, the molar defect concentration of the cation is not 0, and a surface-modified cobalt-based perovskite oxide catalyst is obtained; The La x A 1-x Co y B 1-y O 3-δ The catalyst is used for partial catalytic oxidation of cyclohexane to prepare cyclohexanol and cyclohexanone, the conversion rate of cyclohexane reaches more than 7.6%, and the selectivity of cyclohexanol and cyclohexanone reaches more than 89%.

2. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The calcination temperature in step (2) is 300-800°C; the calcination temperature in step (3) is 300-800°C; the water vapor treatment time in step (3) is 0.5-6h; and the water vapor treatment in step (3) is followed by drying at 60-80°C for 3-12h.

3. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The calcination temperature in step (2) is 500-800°C, and the calcination temperature in step (3) is 500-800°C.

4. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The La x A 1-x Co y B 1-y O 3-δ The surface oxygen vacancy concentration of the catalyst is controlled in the range of δ=0.05-0.

3.

5. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The cobalt salt compound is a +2-valent or +3-valent cobalt salt, and the lanthanum salt compound is a +3-valent lanthanum salt.

6. Use of the cobalt-based perovskite oxide catalyst according to claim 5 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The cobalt-containing salt compound is one or more of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt dichloride or cobalt trichloride; the lanthanum-containing salt compound is one or more of lanthanum acetate, lanthanum sulfate, lanthanum carbonate, lanthanum chloride and lanthanum nitrate.

7. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The salt compound modifier is one or more of sulfate, nitrate, acetate, carbonate and chloride; the La x A 1-x Co y B 1-y O 3-δ In the catalyst, the molar content of metal lanthanum is x=0-0.5, and the molar content of metal cobalt is y=0.01-1.

8. Use of the cobalt-based perovskite oxide catalyst according to claim 7 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The La x A 1-x Co y B 1-y O 3-δ In the catalyst, the molar content of metal cobalt is y=0.01-0.

5.

9. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The complexing agent is one or more of citric acid, tartaric acid, glycine, oxalic acid, ethylenediaminetetraacetic acid, sodium hexametaphosphate, ethanolamine, and polyacrylic acid. The amount of the complexing agent is based on the total molar amount of all metal elements. The complexing reaction temperature is 20-90°C.

10. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The acid solution is capable of hydrolyzing or dissociating H + The acid solution is selected from the group consisting of sodium hydroxide solution, sodium carbonate solution, and ammonium chloride solution. The concentration of the acid solution or the alkaline solution is 0.01-3 mol / L. The soaking treatment temperature is 10-80° C., and the soaking treatment time is 0.1-12 h.

11. Use of the cobalt-based perovskite oxide catalyst according to claim 10 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The acid solution is one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, tartaric acid, oxalic acid, and acetic acid. The concentration of the acid solution or alkaline solution is 0.01-1 mol / L. The soaking treatment temperature is 25-60° C. and the soaking treatment time is 0.5-3 h.

12. Use of the cobalt-based perovskite oxide catalyst according to claim 1 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The partial catalytic oxidation of cyclohexane to prepare cyclohexanol and cyclohexanone is achieved through a one-step reaction process, specifically, under the catalytic action of the cobalt-based perovskite oxide, cyclohexane and an oxygen-containing gas undergo a partial catalytic oxidation reaction to prepare cyclohexanol and cyclohexanone, and the obtained reaction product contains no or only a trace amount of cyclohexyl hydroperoxide, so a subsequent cyclohexyl hydroperoxide decomposition step is not required; the oxygen-containing gas is one of air, oxygen-enriched air, and oxygen, wherein the volume content of oxygen in the oxygen-enriched air is 21%-95%, and the balance gas is one or more of nitrogen, argon, and carbon dioxide.

13. Use of the cobalt-based perovskite oxide catalyst according to claim 12 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The temperature of the cyclohexane partial catalytic oxidation reaction is 100-200°C; the reaction pressure is 0.1-2MPa; the reaction time is 0.2-6h; and the amount of catalyst added is 0.01-3% of the mass of cyclohexane.

14. Use of the cobalt-based perovskite oxide catalyst according to claim 13 in the preparation of cyclohexanol and cyclohexanone by partial catalytic oxidation of cyclohexane, characterized in that: The temperature of the partial catalytic oxidation reaction of cyclohexane is 130-160°C; the reaction pressure is 0.4-1.0Mpa; the reaction time is 0.5-3h; and the amount of catalyst added is 0.01-1% of the mass of cyclohexane.

Images