Use of copper and alkali metal salts, photocatalyst for oxidative cleavage of arene derivatives and process for preparing benzoic acid derivatives
By using copper salts and alkaline metal salts as photocatalysts to activate the CH bonds of aromatic derivatives, the problem of the difficulty in breaking the C-C bonds during the photocatalytic oxidation of polystyrene was solved, and efficient preparation of benzoic acid derivatives was achieved, which is suitable for industrial production.
Patent Information
- Application Number
- CN202311020500.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-14
- Publication Date
- 2026-03-17
- Estimated Expiration
- 2043-08-14
AI Technical Summary
In the existing technology, the C-C bonds are difficult to break during the photocatalytic oxidation degradation of polystyrene, resulting in low selectivity of benzoic acid and limiting its industrial application.
Using copper salt and alkaline metal salt as photocatalysts, benzoic acid derivatives are prepared by photo-oxidative cracking of aromatic hydrocarbon derivatives. The copper salt generates CuCl and chlorine radicals to activate CH bonds, and the alkaline metal ions are used to regulate the activity of metal-oxygen complexes to improve the breaking efficiency of C-C bonds.
It improves the photo-oxidative cracking efficiency of aromatic derivatives, enhances the yield of benzoic acid derivatives, and is simple to operate, operates under mild conditions, and has low cost, making it suitable for industrial production.
Smart Images
Figure CN117049957B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of plastic recycling technology, specifically to the application of copper salts and alkaline metal salts as photocatalysts in the photo-oxidative cracking of aromatic derivatives, a photocatalyst for the oxidative cracking of aromatic derivatives, and a method for preparing benzoic acid derivatives by the photo-oxidative cracking of aromatic derivatives. Background Technology
[0002] Polystyrene (PS) is a widely used thermoplastic, a brittle polymer with a high glass transition temperature. It is widely used in the production of plastic model kits, plastic tableware, insulation materials, electronic products, building products, and medical products. However, PS's high hardness, hydrophobic properties, and corrosion resistance allow it to exist in nature for extended periods without decomposing, causing environmental pollution. Recycling waste PS is therefore of great interest, as it can both protect the environment and conserve resources.
[0003] Upgrading PS chemically into target small molecules is an ideal way to reduce its pollution. Among them, degrading PS waste into useful chemical raw materials is an effective means of degrading PS. Photocatalytic degradation of PS has the characteristics of mild conditions, low cost, and green environmental protection, and is widely used. Among them, the photocatalytic oxidation of PS to benzoic acid has attracted the attention of chemists. For example, Stache et al. (Oh S, Stache E E. Chemical Upcycling of Commercial Polystyrene via Catalyst-Controlled Photooxidation[J]. Journal of the American Chemical Society, 2022(13):144.) reported that under visible light, inexpensive FeCl3 is used as a catalyst and oxygen is used as a green oxidant. FeCl3 is photoexcited to generate chlorine radicals, which promote the degradation of PS to benzoyl products, as shown in formula (1):
[0004]
[0005] However, due to the inertness and stability of the C-C bonds in the PS main chain, it is difficult to break them, and the oxidative degradation process of polystyrene is relatively complex, resulting in low selectivity of benzoic acid in benzoyl products, which limits its industrial value and practical application. Summary of the Invention
[0006] In view of this, the purpose of the present invention is to provide the application of copper salts and alkaline metal salts, photocatalysts for the oxidative cracking of aromatic derivatives, and methods for preparing benzoic acid derivatives. The present invention uses copper salts and alkaline metal salts as photocatalysts for the oxidative cracking of aromatic derivatives, and the degradation of aromatic derivatives to obtain benzoic acid derivatives has high selectivity.
[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0008] This invention provides the application of copper salts and alkaline metal salts as photocatalysts in the photo-oxidative cracking of aromatic derivatives, wherein the alkaline metal salts include one or more of calcium chloride, magnesium chloride, and lithium chloride; and the molar ratio of the copper salt to the alkaline metal salt is 1:0 to 10.
[0009] This invention provides a photocatalyst for the oxidative cracking of aromatic hydrocarbon derivatives, comprising a copper salt and an alkaline metal salt; the alkaline metal salt comprises one or more of calcium chloride, magnesium chloride, and lithium chloride; the molar ratio of the copper salt to the alkaline metal salt is 1:0 to 10.
[0010] Preferably, the copper salt includes one or more of copper chloride, cuprous chloride, copper acetate, copper nitrate, and copper sulfate.
[0011] Preferably, the aromatic derivative includes one or more of polystyrene, toluene derivatives, ethylbenzene derivatives, phenylethanol derivatives, propylbenzene derivatives, butylbenzene derivatives, and lignin model compounds.
[0012] Preferably, the toluene derivative has one or more of the following structures:
[0013]
[0014] The ethylbenzene derivative has one or more of the following structures:
[0015]
[0016] The phenylethanol derivative has one or more of the following structures:
[0017]
[0018] The propylbenzene derivative has one or more of the following structures:
[0019]
[0020] The propylbenzene derivative has one or more of the following structures:
[0021]
[0022] The lignin model compound derivative has one or more of the following structures:
[0023]
[0024] This invention provides a method for preparing benzoic acid derivatives by photo-oxidative pyrolysis of aromatic hydrocarbon derivatives, comprising the following steps:
[0025] Aromatic hydrocarbon derivatives, the oxidative cracking photocatalyst described in the above technical solution, and acetonitrile are mixed and photo-oxidatively cracked under oxygen and blue light irradiation to obtain benzoic acid derivatives.
[0026] Preferably, the molar ratio of the aromatic derivative to the copper salt in the oxidative cracking photocatalyst is 1:0.01 to 1.
[0027] Preferably, the mixing is carried out in darkness under stirring conditions, and the mixing time is 1 to 10 minutes.
[0028] Preferably, the photo-oxidative pyrolysis time is 24–72 h; and the power of the blue light is 30–100 W.
[0029] Preferably, the molar ratio of the aromatic derivative to the volume of acetonitrile is 1 mol: 1 to 10 L.
[0030] This invention provides a photocatalyst for the oxidative cracking of aromatic hydrocarbon derivatives, comprising a copper salt and an alkaline metal salt; the alkaline metal salt includes one or more of calcium chloride, magnesium chloride, and lithium chloride; the molar ratio of the copper salt to the alkaline metal salt is 1:0-10. When the photocatalyst provided by this invention is applied to the photo-oxidative cracking of aromatic hydrocarbon derivatives, the copper salt (taking copper chloride as an example) generates CuCl and chlorine radicals upon irradiation. The chlorine radicals act as hydrogen atom transfer reagents, activating the CH bonds of aromatic hydrocarbon derivatives and lignin-based model compounds to generate alkyl carbon radicals, which combine with O2 to form a peroxide intermediate to obtain benzoic acid derivatives. Furthermore, this invention also utilizes the oxidation-reduction of inactive metal ions (the alkaline metal ions Ca in the alkaline metal salt) to generate benzoic acid derivatives. 2+ Mg 2+ Or Li + The activity of the Lewis acid-regulated metal-oxygen complex intermediate further improves the oxidative cracking effect of aromatic derivatives, significantly increasing the yield of benzoic acid derivatives in the cracking products. The oxidative cracking photocatalyst provided by this invention can efficiently break the C-C bonds in aromatic derivatives, exhibiting high photo-oxidative cracking efficiency and a wide range of reaction substrates. This makes the photo-oxidative cracking of aromatic derivatives to prepare benzoic acid derivatives simple, with mild reaction conditions, low energy consumption, and readily available and low-cost sources, making it suitable for industrial production. Attached Figure Description
[0031] Figure 1 Images of different types of polystyrene. Detailed Implementation
[0032] This invention provides the application of copper salts and alkaline metal salts as photocatalysts in the photo-oxidative cracking of aromatic derivatives, wherein the alkaline metal salts include one or more of calcium chloride, magnesium chloride, and lithium chloride; and the molar ratio of the copper salt to the alkaline metal salt is 1:0 to 10.
[0033] In this invention, the copper salt preferably includes one or more of copper chloride, cuprous chloride, copper acetate, copper nitrate and copper sulfate, and more preferably copper chloride.
[0034] In this invention, the molar ratio of the copper salt to the alkaline metal salt is 1:0 to 10, preferably 1:1 to 8, more preferably 1:3 to 5, and most preferably 1:4.
[0035] In this invention, the aromatic derivatives preferably include one or more of polystyrene, toluene derivatives, ethylbenzene derivatives, phenethyl alcohol derivatives, propylbenzene derivatives, butylbenzene derivatives, and lignin model compounds.
[0036] In this invention, the toluene derivative has one or more of the following structures:
[0037]
[0038] In this invention, the ethylbenzene derivative preferably has one or more of the following structures:
[0039]
[0040] In this invention, the phenylethanol derivative preferably has one or more of the following structures:
[0041]
[0042] In this invention, the propylbenzene derivative preferably has one or more of the following structures:
[0043]
[0044] In this invention, the butylbenzene derivative preferably has one or more of the following structures:
[0045]
[0046] In this invention, the lignin model compound derivative has one or more of the following structures:
[0047]
[0048] This invention does not specifically limit the source and molecular weight of the polystyrene; any polystyrene well-known to those skilled in the art can be used. In specific embodiments of this invention, the polystyrene preferably includes one or more of the following: synthetic polystyrene, polystyrene lunch boxes, polystyrene bowls, polystyrene foam, polystyrene soy milk cup lids, polystyrene cups, polystyrene weighing boats, polystyrene fruit forks, polystyrene spoons, and polystyrene petri dishes. The number-average molecular weight of the polystyrene is preferably 23–390 kg / mol, and the PDI of the polystyrene is preferably 2.8–9.3.
[0049] This invention provides a photocatalyst for the oxidative cracking of aromatic hydrocarbon derivatives, comprising a copper salt and an alkaline metal salt; the alkaline metal salt comprises one or more of calcium chloride, magnesium chloride, and lithium chloride; the molar ratio of the copper salt to the alkaline metal salt is 1:0 to 10.
[0050] In this invention, the types of copper salts, the molar ratio of copper salts to alkaline metal salts, and the types of aromatic derivatives are described above and will not be repeated here.
[0051] This invention provides a method for preparing benzoic acid derivatives by photo-oxidative pyrolysis of aromatic hydrocarbon derivatives, comprising the following steps:
[0052] Aromatic hydrocarbon derivatives, the oxidative cracking photocatalyst described in the above technical solution, and acetonitrile are mixed and photo-oxidatively cracked under oxygen and blue light irradiation to obtain benzoic acid derivatives.
[0053] Unless otherwise specified, all raw materials used in this invention are commercially available products.
[0054] In this invention, the types of aromatic derivatives are the same as those of the aforementioned aromatic derivatives, and will not be repeated here.
[0055] In this invention, the molar ratio of the aromatic derivative to the copper salt in the oxidative cracking photocatalyst is preferably 1:0.01 to 1, more preferably 1:0.02 to 0.5, and even more preferably 1:0.05 to 0.1.
[0056] In this invention, the molar ratio of the aromatic derivative to the volume of acetonitrile is preferably 1 mol: 1 to 10 L, more preferably 1 mol: 5 to 10 L.
[0057] In this invention, when the aromatic derivative is polystyrene, the mixing is preferably performed by mixing the aromatic derivative, the oxidative cracking photocatalyst described in the above-mentioned technical solution, acetonitrile, and benzene; the acetonitrile mainly acts as a co-catalyst, and the benzene is used to dissolve the polystyrene. When the aromatic derivative is not polystyrene, the acetonitrile acts as both a co-catalyst and a solvent.
[0058] In this invention, the mixing is preferably carried out in the dark under stirring conditions, the mixing temperature is preferably 20-35°C, more preferably room temperature, the mixing time is 1-10 min, more preferably 5 min, and there is no special limitation on the stirring speed, as long as the raw materials are mixed evenly.
[0059] In this invention, the oxygen is preferably provided by an oxygen ball.
[0060] In this invention, the temperature of the photo-oxidation pyrolysis is preferably 20-35°C, more preferably room temperature; the time of the photo-oxidation pyrolysis is preferably 24-72h, more preferably 24-60h, and even more preferably 24-48h; the power of the blue light is preferably 30-100W, more preferably 40-80W, and even more preferably 50-60W.
[0061] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0062] Example 1
[0063] Add to a 10 mL Schlenk tube Figure 1 Polystyrene (0.1 mmol), CuCl2 (0.005 mmol), CaCl2 (0.02 mmol), acetonitrile (0.5 mL), and benzene (0.5 mL) were mixed with an oxygen bulb and stirred in the dark for 5 min. Then, the mixture was irradiated with a 50 W blue LED lamp at room temperature for 24 h. The resulting mixture was dissolved in methanol and diluted to volume in a 5 mL volumetric flask. After centrifugation, the yield of benzoic acid in the supernatant was measured by high performance liquid chromatography.
[0064] Table 1. Results of photooxidative pyrolysis of different polystyrene to prepare benzoic acid.
[0065] polystyrene source Number-average molecular weight of polystyrene Polystyrene Number (PDI) Benzoic acid yield synthesis 90kg / mol 9.29 17％ synthesis 110kg / mol 6.45 18％ synthesis 390kg / mol 3.14 20％ lunch box 23kg / mol 4.09 17％ Soy milk cup lid 89kg / mol 2.82 18％ Fruit fork 55kg / mol 3.42 15％ bowl 75kg / mol 3.67 21％ cup 68kg / mol 3.94 24％ Spoon 68kg / mol 3.54 20％ Foam 87kg / mol 3.29 22％ Weighing boat 103 kg / mol 3.24 17％ petri dish 93kg / mol 3.59 20％
[0066] Example 2
[0067] Benzoic acid was prepared by photo-oxidative pyrolysis of polystyrene according to the method of Example 1, wherein the polystyrene was the polystyrene foam in Table 1. The only difference from Example 1 was that CuCl2 was replaced with CuCl, and the yield of benzoic acid was 20%.
[0068] Example 3
[0069] Benzoic acid was prepared by photo-oxidative pyrolysis of polystyrene according to the method of Example 1, wherein the polystyrene was the polystyrene foam of the material listed in Table 1. The only difference from Example 1 was that CuCl2 was replaced with CuSO4·5H2O, and the yield of benzoic acid was 17%.
[0070] Example 4
[0071] Benzoic acid was prepared by photo-oxidative pyrolysis of polystyrene according to the method of Example 1, wherein the polystyrene was the polystyrene foam of the material listed in Table 1. The only difference from Example 1 was that CuCl2 was replaced with Cu(OAc)2·H2O, and the yield of benzoic acid was 8%.
[0072] Example 5
[0073] Benzoic acid was prepared according to the method of Example 1, except that polystyrene was replaced with propylbenzene and no benzene was added, and the yield of benzoic acid was 75%.
[0074]
[0075] Example 6
[0076] Benzoic acid was prepared according to the method of Example 1, except that polystyrene was replaced with a lignin model compound and no benzene was added. The yield of benzoic acid was 66% and the yield of phenyl formate was 71%.
[0077]
[0078] Example 7
[0079] Phenyl formate was prepared according to the method of Example 1, except that polystyrene was replaced with anisole compounds and benzene was not added. The oxidation reaction yielded the corresponding phenyl formate. The reaction raw materials, reaction time, and yield are as follows:
[0080]
[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A process for the photo-oxidative cleavage of an aromatic hydrocarbon derivative to produce benzoic acid, characterized in that, The method comprises the following steps: The aromatic hydrocarbon derivative, the oxidative cleavage photocatalyst, acetonitrile and benzene are mixed with copper salt and basic metal salt as oxidative cleavage photocatalyst, and the benzene is photo-oxidatively cleaved under the conditions of oxygen and blue light irradiation to obtain benzoic acid; The aromatic hydrocarbon derivative is polystyrene; The basic metal salt is calcium chloride; the copper salt is one or more of copper chloride, cuprous chloride, copper acetate and copper sulfate; the molar ratio of the copper salt to the basic metal salt is 1:1-8; The molar ratio of the aromatic hydrocarbon derivative to the copper salt is 1:0.01-1; The mixing is carried out in the dark under stirring, and the mixing time is 1-10 min; The photo-oxidative cleavage time is 24-72 h, and the power of the blue light is 30-100 W.
2. The method of claim 1, wherein, The molar ratio of the copper salt to the basic metal salt is 1:3-5.
3. The method according to claim 1 or 2, characterized in that, The molar ratio of the copper salt to the basic metal salt is 1:
4.
4. The method of claim 1, wherein, The molar ratio of the aromatic hydrocarbon derivative to the copper salt is 1:0.02-0.
5.
5. The method according to claim 1 or 4, characterized in that, The molar ratio of the aromatic hydrocarbon derivative to the copper salt is 1:0.05-0.
1.
6. The method of claim 1, wherein, The ratio of the amount of substance of the aromatic hydrocarbon derivative to the volume of acetonitrile is 1 mol:1-10 L.
7. The method according to claim 1 or 6, characterized in that, The ratio of the amount of substance of the aromatic hydrocarbon derivative to the volume of acetonitrile is 1 mol:5-10 L.
8. The method of claim 1, 2, 4, or 6, wherein, The mixing temperature is 20-35℃.
9. The method of claim 8, wherein, The mixing temperature is room temperature.
10. The method of claim 1, 2, 4, 6, or 9, wherein, The mixing time is 5 min.
11. The method of claim 1, wherein, The oxygen is provided by an oxygen balloon.
12. The method of claim 1 or 11, wherein, The photo-oxidative cleavage temperature is 20-35℃.
13. The method of claim 12, wherein, The photo-oxidative cleavage temperature is room temperature.
14. The method of claim 1, 11, or 13, wherein, The photo-oxidative cleavage time is 24-60 h.
15. The method of claim 14, wherein, The photo-oxidative cleavage time is 24-48 h.
16. The method of claim 1, 11, 13, or 15, wherein, The photo-oxidative cleavage power is 40-80 W.
17. The method of claim 16, wherein, The photo-oxidative cleavage power is 50-60 W.