Lanthanum cobalt composite catalyst, and preparation method and application thereof
By preparing lanthanum-cobalt composite catalysts La2O2SO4, Co4S3, and Co3O4, the problems of high temperature and high pressure and numerous byproducts in the oxidation of ethylbenzene to acetophenone were solved, realizing a highly efficient and green selective oxidation reaction of ethylbenzene using molecular oxygen as an oxidant.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANGZHOU UNIV
- Filing Date
- 2023-11-02
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies for the oxidation of ethylbenzene to prepare acetophenone have problems such as the need for high temperature and high pressure, numerous byproducts, and difficulty in separating the catalyst. Furthermore, the method of using molecular oxygen as an oxidant has not been widely adopted.
Lanthanum-cobalt composite catalysts, consisting of La2O2SO4, Co4S3, and Co3O4, were prepared via a solvothermal method and used to selectively oxidize ethylbenzene under solvent-free conditions with molecular oxygen as the oxidant.
The method achieves efficient and selective oxidation of ethylbenzene to acetophenone under mild reaction conditions. The catalyst is simple to prepare, the raw materials are readily available, the reaction effect is good, and it is environmentally friendly and suitable for large-scale promotion.
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Figure CN117504898B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a lanthanum-cobalt composite catalyst, its preparation method and application, and particularly to a method for preparing a lanthanum-cobalt composite catalyst and its application in the selective oxidation reaction of ethylbenzene, belonging to the field of organic reaction catalyst preparation technology. Background Technology
[0002] Acetophenone is an important raw material for the production of pharmaceuticals, fragrances, resins, and flavorings. In addition, it can be used as a solvent for esters, dyes, and preservatives (New Journal of Chemistry, 2019, 43(21): 8189-8194). Industrially, acetophenone is typically produced through the decomposition of cumene peroxide or the Friedel-Crafts acylation reaction. These reactions generate a large number of corrosive byproducts and require extensive equipment, which does not meet the requirements of green chemical development (Dalton Transactions, 2023, 52(19): 6398-6406). Liquid-phase oxidation of ethylbenzene using a homogeneous catalyst is another important route for acetophenone production; however, this method produces numerous byproducts, and the catalyst is difficult to separate from the product.
[0003] Due to the high bond energy of the CH bonds in ethylbenzene, its activation and oxidation typically require high-temperature and high-pressure oxidation conditions or the addition of a solvent or oxidant to the reaction system. Molecular oxygen, as a renewable resource, is inexpensive and environmentally friendly, making it an ideal oxidant in industrial production. Therefore, the preparation of heterogeneous catalysts with excellent catalytic performance and their application in the selective oxidation of ethylbenzene using molecular oxygen as the oxidant is highly promising. Summary of the Invention
[0004] To achieve the above objectives, the present invention aims to propose a lanthanum-cobalt composite catalyst, its preparation method, and its application. Specifically, it is a method for preparing a heterogeneous catalyst for the solventless molecular oxygen oxidation of ethylbenzene to acetophenone, achieving efficient and selective oxidation of ethylbenzene to acetophenone under relatively mild reaction conditions.
[0005] Technical solution: The present invention adopts the following technical solution.
[0006] The first objective of this invention is to provide a lanthanum-cobalt composite catalyst, wherein the lanthanum-cobalt composite catalyst is composed of La2O2SO4, Co4S3 and Co3O4.
[0007] The second objective of this invention is to provide a method for preparing a lanthanum-cobalt composite catalyst, wherein Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate are dissolved in isopropanol solution to form a reaction solution, a precursor is obtained by solvothermal method, and then the lanthanum-cobalt composite catalyst is prepared by calcination.
[0008] Further, Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate were dissolved in isopropanol solution and stirred for 1-3 hours.
[0009] Further, the solvothermal method includes reacting the reaction solution at 150–200°C for 8–20 h, cooling to room temperature after the reaction is complete, and washing to obtain the precursor. Even further, the reaction solution is reacted at 180–200°C for 12–20 h. Even more further, the reaction solution is reacted at 180°C for 12 h.
[0010] Furthermore, the washing process includes washing the precipitate several times with deionized water and anhydrous ethanol.
[0011] Further, the calcination includes calcining at 500°C for 1–3 hours. Even further, calcining at 500°C for 2–3 hours. Even more specifically, calcining at 500°C for 2 hours.
[0012] Furthermore, the preparation process of the lanthanum-cobalt composite catalyst includes the following steps:
[0013] (1) Dissolve Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate in isopropanol solution and stir for 1-3 hours to form a reaction solution;
[0014] (2) The obtained reaction solution was placed in a kettle and reacted at 150-200℃ for 8-20 hours. After the reaction was completed and cooled to room temperature, the precipitate was washed multiple times with deionized water and anhydrous ethanol to obtain the precursor.
[0015] (3) After drying the obtained precursor, it is calcined at 500℃ for 1-3 hours to obtain the lanthanum-cobalt composite catalyst.
[0016] Furthermore, the molar ratio of Co(NO3)2·6H2O, La(NO3)3·6H2O, and urea is 1:1:(5-15).
[0017] Furthermore, the molar ratio of Co(NO3)2·6H2O, La(NO3)3·6H2O, and urea is 1:1:10.
[0018] Furthermore, the mass ratio of sodium dodecyl sulfate to urea is (0.5–1):1.
[0019] Furthermore, the mass ratio of sodium dodecyl sulfate to urea is 0.625:1.
[0020] Furthermore, the amount of urea dissolved in the isopropanol solution is calculated based on urea, and the concentration of urea dissolved in the isopropanol solution is 0.02–0.05 g / mL.
[0021] Furthermore, the amount of urea dissolved in the isopropanol solution is calculated as urea, and the concentration of urea dissolved in the isopropanol solution is 0.03 g / mL.
[0022] Furthermore, the washed precursor was dried at 75–85°C for 12–24 hours.
[0023] A third objective of this invention is to provide a lanthanum-cobalt composite catalyst prepared by the method described above.
[0024] Furthermore, the composition of the lanthanum-cobalt composite catalyst is La2O2SO4, Co4S3 and Co3O4.
[0025] The fourth objective of this invention is to provide an application of the lanthanum-cobalt composite catalyst described above, specifically, the lanthanum-cobalt composite catalyst is used to prepare acetophenone.
[0026] Furthermore, the preparation of acetophenone refers to the selective oxidation of ethylbenzene with molecular oxygen as the oxidant and without solvent to prepare acetophenone.
[0027] Furthermore, the prepared catalyst was applied to the selective oxidation of ethylbenzene to prepare acetophenone. The reaction process was as follows: the lanthanum-cobalt composite catalyst and ethylbenzene were added to a high-pressure reactor, and molecular oxygen was used as the oxidant. After reacting for a period of time under certain reaction temperature and pressure, the target product acetophenone was obtained.
[0028] Furthermore, the amount of catalyst used is 0.005 to 0.0085 g / mL based on the volume of ethylbenzene.
[0029] Furthermore, the amount of catalyst used is 0.006 to 0.0085 g / mL based on the volume of ethylbenzene.
[0030] Furthermore, the amount of catalyst used is 0.006 to 0.0075 g / mL based on the volume of ethylbenzene.
[0031] Furthermore, the amount of catalyst used is 0.0075 g / mL based on the volume of ethylbenzene.
[0032] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction temperature is 110–140 °C.
[0033] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction temperature is 110–140 °C.
[0034] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction temperature is 110–130°C.
[0035] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction temperature is 120–130°C.
[0036] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction temperature is 130°C.
[0037] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction time is 2-8 hours.
[0038] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction time is 4–8 h.
[0039] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction time is 6-8 hours.
[0040] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction time is 8 hours.
[0041] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction pressure is 0.6–1.0 MPa.
[0042] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction pressure is 0.8–1.0 MPa.
[0043] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the reaction pressure is 0.8 MPa or 1.0 MPa.
[0044] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the conversion rate of ethylbenzene is greater than 40%, and the selectivity of acetophenone is greater than 78%.
[0045] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the conversion rate of ethylbenzene is greater than 67%, and the selectivity of acetophenone is greater than 87%.
[0046] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the conversion rate of ethylbenzene is greater than 73%, and the selectivity of acetophenone is greater than 88%.
[0047] Furthermore, in the selective oxidation of ethylbenzene to prepare acetophenone, the conversion rate of ethylbenzene is greater than 83%, and the selectivity of acetophenone is greater than 89%.
[0048] Compared with the prior art, the advantages of the present invention are as follows:
[0049] (1) The catalyst preparation process of the present invention is simple and the raw materials used are inexpensive and readily available.
[0050] (2) This invention is the first to apply lanthanum-cobalt composite catalyst to the reaction of ethylbenzene oxidation to prepare acetophenone, and uses molecular oxygen as the only oxidant. It is green and environmentally friendly, the catalytic system is simple, the reaction effect is good, and it is conducive to large-scale promotion. Attached Figure Description
[0051] Figure 1 The XRD patterns are those of the lanthanum-cobalt composite catalyst (labeled LaCo-500) prepared in Example 1 and the lanthanum-cobalt composite catalyst (labeled LaCo-800) prepared in Comparative Example 3.
[0052] Figure 2 The image shows a SEM image of the lanthanum-cobalt composite catalyst LaCo-500 prepared in Example 1 of the invention.
[0053] Figure 3 Co3O4 in Comparative Example 1 and LaO in Comparative Example 2 x XRD pattern. Detailed Implementation
[0054] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. The present invention can be better understood from the following embodiments. However, those skilled in the art will readily understand that the specific material ratios, process conditions, and results described in the embodiments are for illustrative purposes only and should not, and will not, limit the present invention as described in the claims.
[0055] Example
[0056] This embodiment describes the preparation process of a lanthanum-cobalt composite catalyst, which specifically includes the following steps:
[0057] (1) Dissolve Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate in isopropanol solution and stir for 1-3 hours to form a reaction solution;
[0058] (2) The obtained reaction solution was placed in a kettle and reacted at 150-200℃ for 8-20 hours. After the reaction was completed and cooled to room temperature, the precipitate was washed multiple times with deionized water and anhydrous ethanol to obtain the precursor.
[0059] (3) After drying the obtained precursor, it is calcined at 500℃ for 1-3 hours to obtain the lanthanum-cobalt composite catalyst.
[0060] Optionally, in one example of this embodiment, the molar ratio of Co(NO3)2·6H2O, La(NO3)3·6H2O, and urea is 1:1:(5-15). Further, the molar ratio of Co(NO3)2·6H2O, La(NO3)3·6H2O, and urea is 1:1:10.
[0061] Optionally, in one example of this embodiment, the mass ratio of sodium dodecyl sulfate to urea is (0.5-1):1. Further, the mass ratio of sodium dodecyl sulfate to urea is 0.625:1.
[0062] Optionally, in one example of this embodiment, the amount of urea dissolved in the isopropanol solution is calculated as urea, and the concentration of urea dissolved in the isopropanol solution is 0.02–0.05 g / mL. Further, the amount of urea dissolved in the isopropanol solution is calculated as urea, and the concentration of urea dissolved in the isopropanol solution is 0.03 g / mL.
[0063] Optionally, in one example of this embodiment, the washed precursor is dried at 75–85°C for 12–24 hours.
[0064] The following are specific embodiments and comparative examples of the present invention, in order to provide a more detailed explanation of the present invention.
[0065] Example 1
[0066] 2.0 mmol Co(NO3)2·6H2O, 2.0 mmol La(NO3)3·6H2O, 1.2 g (20 mmol) urea, and 0.75 g sodium dodecyl sulfate were dissolved in 40 mL of isopropanol solution and stirred for 1 h. The solution was then transferred to a 100 mL reactor and reacted at 180 °C for 12 h. After the reaction, the mixture was filtered and the precipitate was washed repeatedly with deionized water and anhydrous ethanol. The resulting precursor was dried in an oven at 80 °C for 12 h and then calcined in air at 500 °C for 2 h to obtain the LaCo-500 catalyst.
[0067] The obtained LaCo-500 catalyst was subjected to XRD pattern analysis and SEM image analysis to determine its component composition.
[0068] Figure 1 The XRD pattern of the LaCo-500 catalyst prepared in Example 1 is included, showing that it is composed of La2O2SO4, Co4S3 and Co3O4.
[0069] Figure 2 The image shows a SEM image of the LaCo-500 catalyst prepared in Example 1, which shows that the LaCo-500 catalyst is composed of uniformly sized nanoparticles.
[0070] The prepared catalyst was used in the selective oxidation of ethylbenzene to acetophenone. Specifically, 0.15 g of LaCo-500 catalyst and 20 mL of ethylbenzene were added to a high-pressure reactor. The reactor was checked for airtightness and purged three times with oxygen. When the reaction temperature reached 130 °C, oxygen was introduced at 0.8 MPa. After 6 hours of reaction, the product was quantitatively analyzed by gas chromatography. The results showed that the conversion rate of ethylbenzene reached 87.3%, and the selectivity of acetophenone reached 89.7%.
[0071] Comparative Example 1: La(NO3)3·6H2O
[0072] Weigh out 4 mmol of Co(NO3)2·6H2O, 1.2 g of urea, and 0.75 g of sodium dodecyl sulfate, dissolve them in 40 mL of isopropanol solution, and under the same conditions as in Example 1, the resulting product was analyzed and obtained as shown in the figure. Figure 3 The XRD patterns shown demonstrate that a single-metal Co3O4 catalyst was successfully prepared in this comparative example.
[0073] Catalytic performance tests were conducted under the same reaction conditions as in Example 1. The results showed that the conversion rate of ethylbenzene was 54.2% and the selectivity of acetophenone was 84.2%.
[0074] Comparative Example 2: No Co(NO3)2·6H2O
[0075] Weigh out 4 mmol of La(NO3)3·6H2O, 1.2 g of urea, and 0.75 g of sodium dodecyl sulfate, dissolve them in 40 mL of isopropanol solution, and under the same conditions as in Example 1, the resulting product was analyzed and obtained as shown in the figure. Figure 3 The XRD patterns shown indicate that a composite catalyst of La2O2CO3 and La2O2SO4 (labeled as LaO) was successfully prepared in this comparative example. x ).
[0076] Catalytic performance tests were conducted under the same reaction conditions as in Example 1. The results showed that the conversion rate of ethylbenzene was 24.7% and the selectivity of acetophenone was 73.9%.
[0077] Comparative Example 3 without solvothermal treatment
[0078] Weigh out 2.0 mmol Co(NO3)2·6H2O, 2.0 mmol La(NO3)3·6H2O, 1.2 g urea, and 0.75 g sodium dodecyl sulfate, dissolve them in 40 mL of isopropanol solution, and calcine at 800 °C in air for 2 h (labeled as LaCo-800). The resulting product, after monitoring and analysis, yielded the following... Figure 1The XRD pattern shown indicates that it is a composite catalyst composed of LaCoO3, La2O2SO4 and Co3O4.
[0079] Other conditions and reaction conditions were the same as in Example 1. Catalytic performance tests were conducted, and the results showed that the conversion rate of ethylbenzene was 54.9% and the selectivity of acetophenone was 87.7%.
[0080] Example 2
[0081] Example 1 was repeated, except that 0.10 g of LaCo-500 catalyst was added to the reactor. Under the same reaction conditions, the conversion of ethylbenzene was 67.8%, and the selectivity for acetophenone was 87.2%.
[0082] Example 3
[0083] Example 1 was repeated, except that 0.12 g of LaCo-500 catalyst was added to the reactor. Under the same reaction conditions, the conversion of ethylbenzene was 77.0%, and the selectivity of acetophenone was 89.6%.
[0084] Example 4
[0085] Example 1 was repeated, except that 0.17 g of LaCo-500 catalyst was added to the reactor. Under the same reaction conditions, the conversion of ethylbenzene was 83.6%, and the selectivity of acetophenone was 88.9%.
[0086] Example 5
[0087] Example 1 was repeated, except that the ethylbenzene oxidation temperature was 110°C. Under the same reaction conditions, the conversion rate of ethylbenzene was 76.9%, and the selectivity of acetophenone was 90.3%.
[0088] Example 6
[0089] Example 1 was repeated, except that the ethylbenzene oxidation reaction temperature was 140°C. Under the same reaction conditions, the conversion rate of ethylbenzene was 77.6%, and the selectivity of acetophenone was 88.7%.
[0090] Example 7
[0091] Example 1 was repeated, except that the ethylbenzene oxidation reaction time was 2 hours. Under the same reaction conditions, the conversion rate of ethylbenzene was 67.0%, and the selectivity of acetophenone was 88.9%.
[0092] Example 8
[0093] Example 1 was repeated, except that the ethylbenzene oxidation reaction time was 4 hours. Under the same reaction conditions, the conversion rate of ethylbenzene was 73.6%, and the selectivity of acetophenone was 89.0%.
[0094] Example 9
[0095] Example 1 was repeated, except that the ethylbenzene oxidation reaction time was 8 hours. Under the same reaction conditions, the conversion rate of ethylbenzene was 88.0%, and the selectivity of acetophenone was 90.6%.
[0096] Example 10
[0097] Example 1 was repeated, except that the ethylbenzene oxidation reaction pressure was 0.6 MPa. Under the same reaction conditions, the conversion rate of ethylbenzene was 40.9%, and the selectivity of acetophenone was 78.1%.
[0098] Example 11
[0099] Example 1 was repeated, except that the ethylbenzene oxidation reaction pressure was 1.0 MPa. Under the same reaction conditions, the conversion rate of ethylbenzene was 88.5%, and the selectivity of acetophenone was 88.8%.
[0100] Those skilled in the art will readily understand that the above-described embodiments are merely for the purpose of more clearly illustrating the present invention and are not intended to limit the present invention. Any extensions, modifications, substitutions, improvements, etc., made within the spirit and principles of the present invention should be within the protection scope of the present invention.
Claims
1. A lanthanum-cobalt composite catalyst, characterized in that, The lanthanum-cobalt composite catalyst is composed of La2O2SO4, Co4S3 and Co3O4; the preparation method of the lanthanum-cobalt composite catalyst includes dissolving Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate in isopropanol solution to form a reaction solution, obtaining the precursor by solvothermal method, and then preparing the lanthanum-cobalt composite catalyst by calcination. The molar ratio of Co(NO3)2·6H2O, La(NO3)3·6H2O, and urea is 1:1:(5-15), and the mass ratio of sodium dodecyl sulfate to urea is (0.5-1):
1.
2. The lanthanum-cobalt composite catalyst according to claim 1, characterized in that, The amount of urea dissolved in the isopropanol solution is calculated as urea, and the concentration of urea dissolved in the isopropanol solution is 0.02-0.05 g / mL.
3. The lanthanum-cobalt composite catalyst according to claim 1, characterized in that, Co(NO3)2·6H2O, La(NO3)3·6H2O, urea and sodium dodecyl sulfate were dissolved in isopropanol solution and stirred for 1-3 hours. The solvothermal method includes reacting the reaction solution at 150-200°C for 8-20 hours, cooling the reaction to room temperature after completion, and washing to obtain the precursor. The washing process includes washing the precipitate several times with deionized water and anhydrous ethanol. The washed precursor was dried at 75–85°C for 12–24 hours. The roasting process includes roasting at 500°C for 1 to 3 hours.
4. The application of the lanthanum-cobalt composite catalyst according to any one of claims 1-3, characterized in that, The lanthanum-cobalt composite catalyst is used to prepare acetophenone, wherein the preparation of acetophenone refers to the selective oxidation of ethylbenzene with molecular oxygen as the oxidant and without solvent to prepare acetophenone.
5. The application according to claim 4, characterized in that, The lanthanum-cobalt composite catalyst and ethylbenzene were added to a high-pressure reactor, and acetophenone was prepared using molecular oxygen as an oxidant.
6. The application according to claim 4, characterized in that, The amount of the lanthanum-cobalt composite catalyst used is 0.005–0.0085 g / mL based on the volume of ethylbenzene.
7. The application according to claim 4, characterized in that, The reaction temperature is 110–140℃, the reaction time is 2–8 h, and the reaction pressure is 0.6–1.0 MPa.