CN110694632A - Preparation method and application of cobalt-cerium composite oxide catalyst - Google Patents
Preparation method and application of cobalt-cerium composite oxide catalyst Download PDFInfo
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Abstract
The invention discloses a preparation method and application of a cobalt-cerium composite oxide catalyst. The cobalt salt compound, the cerium salt compound and the metal ion modifier are dissolved in water, then a reducing agent is added for reduction reaction, then a precipitator is added for coprecipitation reaction under the action of ultrasonic waves or microwaves, and the obtained precipitate is dried and then is roasted in an oxygen-containing atmosphere, so that the composite oxide catalyst containing cobalt with different valence states and cerium with different valence states is obtained and is used for cyclohexane oxidation reaction to prepare the KA oil in one step with high selectivity. The cobalt-cerium composite oxide catalyst obtained by the invention can activate reaction substrates, can promote the rapid conversion of reaction intermediates, shows strong synergistic catalysis, greatly improves the reaction process efficiency and the KA oil yield, is easy to separate, has good stability, and is an environment-friendly heterogeneous catalyst.
Description
Technical Field
The invention relates to preparation of a catalyst, in particular to a preparation method and application of a cobalt-cerium composite oxide catalyst.
Background
The KA oil is a mixture of cyclohexanone and cyclohexanol. Cyclohexanone, organic compounds, saturated cyclic ketones containing carbonyl carbon atoms in six-membered rings, colorless transparent liquids, formula C6H10O, molecular weight 98.14, melting point-47 deg.C, boiling point 155 deg.C. Cyclohexanol is an organic compound of formula C6H12O, a colorless viscous liquid at normal temperature and pressure, with a molecular weight of 100.158, a melting point of 25.93 ℃ and a boiling point of 161.84 ℃. The KA oil has wide application in the fields of pesticide, medicine, paint, detergent and other industries, and is also an important intermediate for producing nylon-6 and nylon-66. There are many reports on methods for producing KA oil, and at present, the industry mainly adopts a two-step method of cyclohexane oxidation-cyclohexyl hydroperoxide decomposition: cyclohexane is firstly oxidized with oxygen to obtain the oxidation products of cyclohexyl hydroperoxide and cyclohexanone and cyclohexanol, and then the cyclohexyl hydroperoxide is catalyzed and decomposed into cyclohexanone and cyclohexanol under the alkaline condition. In the two-step process, the temperature of the cyclohexane oxidation reaction is 160-170 ℃, the single-pass conversion rate of the cyclohexane is generally 3-4%, and the total yield of the KA oil is only 81-83%. Not only has high energy and material consumption, but also produces a large amount of saponification waste lye. Therefore, the development of green and efficient catalysts to improve the technical level of preparing KA oil by cyclohexane oxidation is urgently needed.
Patent US4326084 reports the preparation of KA oil in a two-step process using soluble cobalt salts as homogeneous catalysts: cyclohexane is first oxidized to form a mixture containing cyclohexyl hydroperoxide, which is then decomposed to KA oil at 151-154 ℃. The method is a homogeneous catalysis process, the catalyst is easy to scale, and two steps are needed to obtain the KA oil. In order to obtain high KA oil yield, the conversion rate of cyclohexane is required to be controlled to be below 4%, and the maximum decomposition rate of cyclohexyl hydroperoxide is 97%.
Patent JP2000239210a2(2000) uses a mixture of N-hydroxyphthalimide (NHPI) and cobalt acetylacetonate as a homogeneous catalyst for the direct oxidation of cyclohexane to KA oil; the reaction temperature is 160 ℃, the reaction pressure is 4.0MPa, the reaction time is 2 hours, the cyclohexane conversion rate is 11 percent, and the KA oil selectivity is 89 percent. Although the technology has higher conversion rate and selectivity, the catalyst dosage in the reaction process is larger (the mass of cobalt acetylacetonate accounts for about 6.8% of cyclohexane, and the dosage of NHPI accounts for about 17% of cyclohexane), the catalyst cost is higher, the reaction pressure is higher, the catalyst stability is poorer, the recovery is difficult, and the industrial application is not facilitated.
Patent US7045667B2 reports that when a cerium-zirconium composite oxide catalyst prepared by a common coprecipitation method is used for cyclohexane oxidation reaction, under the conditions of reaction temperature of 120 ℃, air pressure of 1.1MPa and reaction time of 5 hours, the conversion rate of cyclohexane is about 1.4%, and the selectivity of KA oil is about 75%. The catalyst has low activity and selectivity.
The patent DE19832016A1(1983) reports that oxides of Cr, V and Co are loaded on an MCM-41 molecular sieve by a common impregnation method to obtain a loaded catalyst, cyclohexane is oxidized by a gas phase method to prepare KA oil, the reaction is carried out at 200-350 ℃, the conversion rate of the cyclohexane is about 4 percent, and the selectivity of the KA oil is about 80 percent. Although the method adopts a heterogeneous catalyst, the reaction temperature is higher, and the activity and selectivity of the catalyst are not ideal and are lower than the prior industrial level.
Patent WO99/40055(1999) and patent US006160183A (2000) report that the gold-containing noble metal catalyst prepared by the general sol-gel method reacts at 170 ℃, the conversion rate of cyclohexane is 4.7%, and the total selectivity of KA oil and cyclohexyl hydroperoxide is 86.2%. The catalyst adopts noble metal, the cost of the catalyst is high, and the activity and the selectivity of the catalyst are not ideal.
Lu, h, and Dai, s, et al report a reaction for selectively oxidizing cyclohexane at a relatively low temperature using a manganese-cerium solid solution catalyst prepared by a complex method with addition of an ionic liquid (Nature Communications,2015,6: 1-10). With Mn0.5Ce0.5OxA solid solution catalyst,Acetonitrile is used as a solvent, the reaction time is 12 hours at the reaction temperature of 100 ℃ and the oxygen pressure of 1MPa, the conversion rate of cyclohexane can reach 17.7 percent, and the selectivity of KA oil is 81 percent. The method really achieves better technical effect, but the preparation process of the catalyst is complex, and toxic ionic liquid is used as a complexing agent and a template agent; the reaction process requires the use of large amounts of acetonitrile solvent (about three times the volume of cyclohexane), which increases the difficulty and cost of work-up and environmental pressure.
Disclosure of Invention
Aiming at the technical problems, the invention provides a preparation method and application of a cobalt-cerium composite oxide catalyst. The method is characterized in that quantitative cobalt-containing salt compounds, cerium-containing salt compounds and metal ion modifiers are dissolved in water, then reducing agents are added for reduction reaction, then precipitating agents are added for coprecipitation reaction under the action of ultrasonic waves or microwaves, obtained precipitates are dried and then are roasted in oxygen-containing atmosphere, and therefore composite oxide catalysts containing cobalt with different valence states and cerium with different valence states are obtained, the obtained catalysts are used for cyclohexane oxidation reaction, and KA oil is prepared in one step in a high-selectivity mode. The cobalt-cerium composite oxide catalyst disclosed by the invention can activate a reaction substrate and promote the rapid conversion of a reaction intermediate, and an oxidation product does not contain or only contains trace cyclohexyl hydrogen peroxide, so that a subsequent decomposition process is not needed, the catalyst shows a strong synergistic catalytic action, the reaction process efficiency and the KA oil yield are greatly improved, and the catalyst is easy to separate and good in stability, and is an environment-friendly heterogeneous catalyst.
The technical scheme of the invention is as follows:
a preparation method of a cobalt-cerium composite oxide catalyst comprises the following steps:
(1) taking a cobalt salt compound as a cobalt source and a cerium salt compound as a cerium source, stirring and dissolving the cobalt salt compound and the cerium salt compound in water to obtain a solution A, and adding a reducing agent into the solution A to perform a reduction reaction so that cobalt ions and cerium ions in the solution A are partially reduced;
(2) stirring and dissolving the coprecipitate in water to obtain a solution B;
(3) slowly adding the solution B into the solution A under the ultrasonic or microwave-assisted condition, carrying out ultrasonic coprecipitation reaction, then adjusting the pH value of the solution, drying the obtained precipitate, and roasting in an oxygen-containing atmosphere to obtain the cobalt-cerium composite oxide catalyst, wherein cobalt and cerium have different valence states.
The method further comprises the step (1) of adding a modifier into the solution A, wherein the modifier is added before a reducing agent, the modifier is a salt compound containing metal ions except cobalt and cerium, the metal element is preferably one or more of transition metal, alkali metal or alkaline earth metal, more preferably Fe, Mn, Cu, V, Zr, Ti, La, Y, Sm, Li, Na, K, Mg, Ca, Sr or Ba, and the salt compound is preferably one or more of sulfate, nitrate, acetate, carbonate or chloride; the modifier is used in a molar ratio of the metal to cerium in the modifier of 0 to 10, preferably 0.001 to 5.0, and more preferably 0.01 to 1.0.
Further, in the step (1), the cobalt salt compound is a cobalt salt with a valence of +2 or +3, preferably one or more of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt dichloride and cobalt trichloride; the cerium salt compound is a +3 or +4 valent cerium salt, preferably one or more of cerium sulfate, ceric sulfate, cerium chloride, cerium nitrate, ceric nitrate and ammonium ceric nitrate; the dosage ratio of the cobalt salt and the cerium salt is 0.001-100.0, preferably 0.005-10.0, and more preferably 0.01-5.0 in terms of the molar ratio of cobalt to cerium.
Further, in the step (1), the reducing agent is hydrogen gas or NaBH4One or more than two of vitamin C, isobutanol and benzyl alcohol; the reducing agent is used in terms of the reduction conversion rate of cobalt and cerium: the total reduction conversion of cobalt and cerium is 0.01 or more, preferably 0.05 to 0.8, more preferably 0.1 to 0.5.
In step (2), the coprecipitator is an alkaline compound, preferably one or more of alkali metal or alkaline earth metal hydroxide, alkali metal carbonate, urea, ammonia, ammonium carbonate or ammonium bicarbonate, and the amount of the coprecipitator added is 1 to 1.5 times of the stoichiometric ratio.
Further, in the step (3), the pH value of the solution is adjusted to 7.5-14, preferably 9-13 by dropwise adding ammonia water under the stirring condition; the temperature of the coprecipitation reaction is less than or equal to 100 ℃, preferably less than or equal to 80 ℃, and more preferably less than or equal to 60 ℃.
Further, in the step (3), the roasting temperature is 200-800 ℃, preferably 300-700 ℃, and the roasting time is 1-6 hours, preferably 2-4 hours.
The catalyst prepared by the preparation method is used for selective catalytic oxidation of hydrocarbons, preferably for catalytic oxidation of cyclohexane.
Further, the catalytic oxidation of cyclohexane to cyclohexane oxide further prepares KA oil, and specifically comprises the following steps: under the action of the cobalt cerium composite oxide catalyst, cyclohexane and air or oxygen-enriched air or oxygen are subjected to catalytic oxidation reaction, and the product does not contain or only contains trace cyclohexyl hydroperoxide, so that the subsequent decomposition step of the cyclohexyl hydroperoxide is not needed.
Further, the temperature of the catalytic oxidation reaction is 100-200 ℃, preferably 130-170 ℃; the pressure is 0.1-2MPa, preferably 0.4-1.0 MPa.
The invention has the beneficial effects that:
according to the preparation method of the catalyst, the active metal element of the catalyst forms a special heterojunction interface containing different species through the coexistence process of simple substance-low valence ion-high valence ion, so that the synthesized cobalt-cerium composite oxide catalyst has special heterojunction interface and surface interface properties, and shows good performance of catalyzing cyclohexane oxidation to prepare KA oil in one step. The conversion rate of cyclohexane can reach more than 5%, the selectivity of KA oil can reach more than 90%, the efficiency of the reaction process is higher than the existing industrial level, the reaction condition is mild, an organic solvent is not used, the adopted cobalt-cerium composite oxide catalyst is stable in performance, easy to separate and reusable, and the method is an environment-friendly method for producing KA oil. The cobalt cerium composite oxide catalyst of the invention can also be applied to selective catalytic oxidation of other hydrocarbons.
Drawings
FIG. 1 is an X-ray diffraction (XRD) spectrum of a catalyst obtained under different preparation conditions of the present invention, wherein a: Co3O4B is cobalt cerium composite oxide catalyst (Ce: Co 2:1 without ultrasonic), c is cobalt cerium composite oxide catalyst (Ce: Co 2:1 without reducing agent), d is CeO2And e, cobalt cerium composite oxide catalyst (Ce: Co ═ 2:1, reducing agent and ultrasonic wave).
Detailed Description
The following examples are intended to illustrate the invention, but not to limit it. In the examples a batch process is described.
Example 1: preparation of cobalt cerium composite oxide catalyst: respectively weighing 4.4g of cerous nitrate hexahydrate and 1.5g of cobalt nitrate hexahydrate, adding 250ml of deionized water, stirring to completely dissolve the cerous nitrate hexahydrate and the cobalt nitrate hexahydrate to obtain a solution A, adding NaBH into the solution A at room temperature4The cobalt ions and cerium ions in the solution A are partially reduced. 3.1g of potassium carbonate was weighed and placed in a 100ml beaker, and 50ml of deionized water was added thereto and stirred to completely dissolve the potassium carbonate, thereby obtaining a solution B. And then slowly adding the solution B into the solution A under the ultrasonic condition, carrying out coprecipitation reaction at 40 ℃, then dropwise adding ammonia water into the mixture containing the precipitate under the stirring condition to adjust the pH value of the solution, continuously stirring to stabilize the pH value of the solution at 10, filtering and washing the obtained precipitate, drying at 120 ℃ for 12 hours, and roasting at 400 ℃ in a muffle furnace for 2 hours to obtain the cobalt-cerium composite oxide catalyst C-1.
Comparative example 1: the preparation method of the cobalt-cerium composite oxide catalyst is the same as that of example 1, except that: and (3) adding no reducing agent into the solution A, namely adding no reducing agent to prepare the cobalt-cerium composite oxide catalyst C-2.
Comparative example 2: the preparation method of the cobalt-cerium composite oxide catalyst is the same as that of example 1, except that: and (3) carrying out coprecipitation reaction without ultrasonic wave, namely, without ultrasonic wave, so as to obtain the cobalt-cerium composite oxide catalyst C-3.
Example 2: the preparation method of the cobalt-cerium composite oxide catalyst is the same as that of example 1, except that: 0.43g of lanthanum nitrate hexahydrate is additionally added into the mixed solution A as a modifier to prepare the cobalt-cerium composite oxide catalyst C-4.
Example 3: the preparation method of the cobalt cerium composite oxide catalyst is the same as that of example 1. The difference lies in that: 0.10g of potassium nitrate as a modifier was additionally added to the mixed solution A, and the amount of the reducing agent was changed to 0.04g of NaBH4To obtain the cobalt cerium composite oxide catalyst C-5.
Example 4: the preparation method of the cobalt cerium composite oxide catalyst is the same as that of example 1. The difference lies in that: 0.15g of strontium nitrate was added to the mixed solution A, and the amount of isobutanol was changed to 0.08g as a reducing agent, to obtain cobalt-cerium composite oxide catalyst C-6.
Example 5: the preparation method of the cobalt cerium composite oxide catalyst is the same as that of example 1. The difference lies in that: the roasting temperature is 200 ℃, and the composite oxide catalyst C-7 is prepared.
Comparative example 3: the preparation method of the cobalt cerium composite oxide catalyst is the same as that of example 1. The difference lies in that: the roasting temperature is 900 ℃, and the composite oxide catalyst C-8 is prepared.
Example 6: 60g of cyclohexane and 0.1g of cobalt cerium composite oxide C-1 are weighed and placed in a 250ml kettle reactor, the temperature is raised and stirred, and when the temperature approaches 130 ℃, molecular oxygen is introduced to reach 0.5 MPa. When the temperature is raised to 140 ℃, the oxygen pressure is increased to 0.6Mpa to reach the reaction pressure of 0.6Mpa, and the pressure is maintained at 0.6Mpa in the reaction process. When the temperature rises to 150 ℃, the reaction is started for 1.5 hours. After the reaction is finished, the reaction kettle is cooled to room temperature. The catalyst was separated from the liquid phase product by centrifugation. And (3) quantitatively analyzing the KA oil in the liquid-phase product by adopting a gas chromatography internal standard method (chlorobenzene is used as an internal standard substance), titrating the cyclohexyl hydroperoxide by adopting triphenylphosphine to convert the cyclohexyl hydroperoxide into cyclohexanol, quantitatively analyzing by adopting the gas chromatography internal standard method, and quantitatively analyzing the byproduct acid and ester by adopting acid-base titration. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 7: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-2. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 8: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-3. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 9: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-4. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 10: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-5. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 11: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-6. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 12: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-7. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 13: the reaction procedure and procedure were the same as in example 6 except that: adopts cobalt cerium composite oxide catalyst C-8. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 14: the reaction procedure and procedure were the same as in example 6 except that: the reaction time was 1 h. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 15: the reaction procedure and procedure were the same as in example 6 except that: the reaction time was 2 h. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 16: the reaction procedure and procedure were the same as in example 6 except that: the reaction temperature was 130 ℃. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 17: the reaction procedure and procedure were the same as in example 6 except that: the reaction temperature was 160 ℃. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 18: the reaction procedure and procedure were the same as in example 6 except that: the reaction pressure was 0.5 MPa. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 19: the reaction procedure and procedure were the same as in example 6 except that: the reaction pressure was 0.7 MPa. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 20: the reaction procedure and procedure were the same as in example 6 except that: the reaction pressure was 0.8 MPa. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 21: the reaction procedure and procedure were the same as in example 6 except that: the catalyst is CeO2. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 22: the reaction procedure and procedure were the same as in example 6 except that: the catalyst is Co3O4. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
Example 23: the reaction procedure and procedure were the same as in example 6 except that: no catalytic oxidation is carried out, and the reaction time is 2 hours. The cyclohexane conversion and selectivity of KA oil and cyclohexyl hydroperoxide obtained are analyzed and shown in Table 1.
TABLE 1 analysis of cyclohexane oxidation
| Example number | Conversion of cyclohexane | Selectivity of KA oil | Cyclohexyl hydroperoxide selectivity |
| 6 | 5.8 | 90.6 | 0 |
| 7 | 3.5 | 82.8 | 0 |
| 8 | 4.9 | 81.8 | 0 |
| 9 | 6.2 | 93.2 | 0 |
| 10 | 6.0 | 92.1 | 0 |
| 11 | 6.7 | 92.3 | 0 |
| 12 | 3.8 | 81.6 | 13.8 |
| 13 | 6.9 | 72.0 | 0 |
| 14 | 5.1 | 91.8 | 0 |
| 15 | 7.3 | 86.0 | 0 |
| 16 | 0.1 | 89.9 | 9.5 |
| 17 | 8.5 | 80.0 | 0 |
| 18 | 2.4 | 96.0 | 0 |
| 19 | 8.2 | 85.2 | 0 |
| 20 | 11.5 | 77.2 | 0 |
| 21 | 5.4 | 78.6 | 14.7 |
| 22 | 6.9 | 73.6 | 12.4 |
| 23 | 2.3 | 42.5 | 53.6 |
As can be seen from Table 1, the catalyst obtained by the invention can obtain good catalytic effect, the conversion rate of cyclohexane can reach more than 5%, the selectivity of KA oil can reach more than 90%, the use of the modifier can further improve the catalytic effect, and the catalytic effect is obviously reduced without adding a reducing agent (comparative example 1), ultrasound (comparative example 2) or overhigh roasting temperature (comparative example 3) in the preparation process of the catalyst.
According to the preparation method, the active metal element of the catalyst forms a special heterojunction interface containing different species through the coexistence process of simple substance-low valence ion-high valence ion, and the active component cobalt can be highly and uniformly dispersed in the catalyst system, so that the synthesized cobalt-cerium composite oxide catalyst has special heterojunction interface and surface interface properties and shows good catalytic cyclohexane oxidation performance. The X-ray diffraction pattern of the cobalt-cerium composite oxide catalyst is shown in FIG. 1. As can be seen from FIG. 1, the diffraction peak intensity of the catalyst is not high without the addition of ultrasound (curve b in FIG. 1) or the addition of a reducing agent (curve c in FIG. 1), and is 32.5 degrees at 2 θWhere (represents CeO)2The (121) crystal plane) diffraction peak of (a) is not conspicuous. In addition, under the conditions of the reducing agent and the ultrasound (e curve in fig. 1), a new diffraction peak appears at an angle of 23.6 ° of 2 θ, indicating that under the action of the reducing agent and the ultrasound, the bulk composition of the cobalt-cerium composite oxide catalyst is different from that of the catalyst without the reducing agent or the ultrasound. In addition, reduction and ultrasonic means are adopted in the preparation process of the catalyst, and obviously, no characteristic diffraction peak of a Co component is observed, which indicates that the Co serving as an active component can be highly dispersed in cerium dioxide, and thus, the reduction and ultrasonic means adopted by the invention are fully indicated, and the active component can be uniformly dispersed in a catalyst system.
Claims (10)
1. The preparation method of the cobalt-cerium composite oxide catalyst is characterized by comprising the following steps of:
(1) taking a cobalt salt compound as a cobalt source and a cerium salt compound as a cerium source, stirring and dissolving the cobalt salt compound and the cerium salt compound in water to obtain a solution A, and adding a reducing agent into the solution A to perform a reduction reaction so that cobalt ions and cerium ions in the solution A are partially reduced;
(2) stirring and dissolving the coprecipitate in water to obtain a solution B;
(3) slowly adding the solution B into the solution A under the ultrasonic or microwave-assisted condition, carrying out ultrasonic coprecipitation reaction, finally adjusting the pH value of the solution, drying the obtained precipitate, and roasting in an oxygen-containing atmosphere to obtain the cobalt-cerium composite oxide catalyst.
2. The method for preparing a cobalt-cerium composite oxide catalyst according to claim 1, further comprising the step of (1) adding a modifier into the solution a, wherein the modifier is added before the reducing agent, the modifier is a salt compound containing metal ions other than cobalt and cerium, the metal element is a transition metal, an alkali metal or an alkaline earth metal, and the salt compound is one or more of sulfate, nitrate, acetate, carbonate or chloride; the amount of the modifier is calculated by the molar ratio of metal to cerium in the modifier, and the molar ratio of the metal to cerium in the modifier is 0-10 and is more than 0.
3. The method of producing a cobalt-cerium composite oxide catalyst according to claim 2, wherein the metal element in the modifier is one or more of Fe, Mn, Cu, V, Zr, Ti, La, Y, Sm, Li, Na, K, Mg, Ca, Sr, or Ba; the molar ratio of the metal to cerium in the modifier is 0.001-5.0.
4. The method for preparing a cobalt-cerium composite oxide catalyst according to claim 1 or 2, wherein in the step (1), the cobalt salt compound is one or more of cobalt acetate, cobalt carbonate, cobalt nitrate, cobalt sulfate, cobalt dichloride, or cobalt trichloride; the cerium salt compound is one or more than two of cerium sulfate, ceric sulfate, cerium chloride, cerium nitrate, ceric nitrate and ammonium ceric nitrate; the dosage ratio of the cobalt salt to the cerium salt is calculated by the molar ratio of cobalt to cerium, and the molar ratio of cobalt to cerium is 0.001-100.0.
5. The method for preparing a cobalt-cerium composite oxide catalyst according to claim 1 or 2, wherein in the step (1), the reducing agent is hydrogen gas or NaBH4One or more than two of vitamin C, isobutanol and benzyl alcohol; the reducing agent is used in terms of the reduction conversion rate of cobalt and cerium: the total reduction conversion rate of the cobalt and the cerium is more than or equal to 0.01.
6. The method of claim 1 or 2, wherein in the step (2), the coprecipitator is one or more of a hydroxide of an alkali metal or an alkaline earth metal, an alkali metal carbonate, urea, ammonia, ammonium carbonate, or ammonium bicarbonate, and the amount of the coprecipitator added is 1 to 1.5 times of the stoichiometric ratio.
7. The preparation method of the cobalt cerium composite oxide catalyst according to claim 1 or 2, wherein in the step (3), the pH value of the solution is adjusted to 7.5-14 by dropwise adding ammonia water under stirring; the temperature of the coprecipitation reaction is less than or equal to 100 ℃.
8. The method for preparing a cobalt-cerium composite oxide catalyst according to claim 1 or 2, wherein in the step (3), the calcination temperature is 200 to 800 ℃ and the calcination time is 1 to 6 hours.
9. Use of a catalyst obtained by the process according to any one of claims 1 to 8 for the selective catalytic oxidation of hydrocarbons.
10. The use according to claim 9, characterized in that said selective catalytic oxidation of hydrocarbons is the catalytic oxidation of cyclohexane, said catalytic oxidation of cyclohexane being the oxidation of cyclohexane to produce KA oil in one step, in particular: under the action of the cobalt cerium composite oxide catalyst, cyclohexane and air or oxygen-enriched air or oxygen are subjected to catalytic oxidation reaction at the reaction temperature of 100-200 ℃ and the pressure of 0.1-2 MPa.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN114950452A (en) * | 2022-05-25 | 2022-08-30 | 万华化学集团股份有限公司 | Catalyst for synthesizing L-2-aminopropanol, preparation method thereof and method for synthesizing L-2-aminopropanol |
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| CN116459840A (en) * | 2023-02-24 | 2023-07-21 | 湘潭大学 | Cobalt-based perovskite oxide catalyst and preparation and application thereof |
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| CN113171777A (en) * | 2021-04-26 | 2021-07-27 | 湖南大学 | Iron/cerium bimetallic heterogeneous electro-Fenton catalyst and preparation method and application thereof |
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| CN114950452A (en) * | 2022-05-25 | 2022-08-30 | 万华化学集团股份有限公司 | Catalyst for synthesizing L-2-aminopropanol, preparation method thereof and method for synthesizing L-2-aminopropanol |
| CN114950452B (en) * | 2022-05-25 | 2024-05-03 | 万华化学集团股份有限公司 | Catalyst for synthesizing L-2-aminopropanol and preparation method thereof, and method for synthesizing L-2-aminopropanol |
| CN116173959A (en) * | 2022-12-12 | 2023-05-30 | 陕西科技大学 | Reverse ZrO 2 -Co catalyst and catalytic Co thereof 2 Hydrogenation synthesis C 5+ Use of alkanes |
| CN116459840A (en) * | 2023-02-24 | 2023-07-21 | 湘潭大学 | Cobalt-based perovskite oxide catalyst and preparation and application thereof |
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