Preparation method of porphyrin-based polymer and ethylene oxide

Abstract

The invention discloses a porphyrin-based polymer and a preparation method of ethylene oxide. According to the method, carbon dioxide, water and oxygen are used as raw materials, a copper oxide-porphyrin-based polymer composite material is used as a catalyst, the reaction temperature is 20-150 DEG C, the reaction pressure is 0.05-2.0 MPa, and a catalytic reaction is carried out under the conditions of electrolysis and illumination to obtain the ethylene oxide. The method has the advantages of green and mild reaction conditions, cheap and easily available raw materials, good catalytic effect, simple process and the like.

Description

Technical Field

[0001] This invention relates to a method for preparing ethylene oxide, and more specifically, to a porphyrin-based polymer and a method for preparing ethylene oxide. Background Technology

[0002] Ethylene oxide is an important chemical product used in the production of organic synthesis intermediates and high molecular weight polymers, such as ethylene glycol, polycarboxylate superplasticizer monomers, polyethers, and ethylene glycol; it can also be used to synthesize detergents, nonionic surfactants, and antifreeze. The main methods for preparing ethylene oxide are the direct oxidation of ethylene and the chlorohydrin process.

[0003] The chlorohydrin process for synthesizing ethylene oxide involves reacting chlorine and water to produce hypochlorous acid, which is then reacted with ethylene to produce the final product. While the chlorohydrin process is relatively mature, it causes severe equipment corrosion and generates large amounts of chlorine-containing wastewater and waste residue, failing to meet the requirements of green chemistry and clean production. With increasingly stringent environmental protection requirements, the chlorohydrin process for producing ethylene oxide will be phased out due to environmental pollution and other issues.

[0004] Besides the chlorohydrin method, ethylene epoxidation is also a commonly used method for preparing ethylene oxide. Invention patents CN1383915 and CN1438920 disclose processes for preparing ethylene oxide using silver-based catalysts through ethylene epoxidation. CN1649671 and CN1802206 disclose processes for preparing ethylene oxide using alumina-based catalysts through ethylene epoxidation. While ethylene epoxidation can achieve the preparation of ethylene oxide, it requires obtaining ethylene first, resulting in higher process costs.

[0005] CN116113624A discloses a process for directly preparing ethylene oxide from oxygen and carbon dioxide, but the overall process involves multiple steps that need to be carried out in stages, making the process complex.

[0006] Therefore, developing a process for preparing ethylene oxide using oxygen, carbon dioxide, and water as raw materials and employing green energy will be of great significance and application value. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a newly synthesized porphyrin-based polymer and the composite catalyst prepared therefrom, which can provide a mild, green, and efficient method for selectively catalyzing oxygen, carbon dioxide, and water to produce ethylene oxide.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A porphyrin-based polymer with the structure shown in general formula (I), wherein M in general formula (I) is one of the following: metal-free or transition metal atoms: Fe, Zn, Co, Mn, Cu, Ni, and Mg; and the monomer group R is selected from one of the following: terephthalaldehyde, 2,5-dimethoxyterephthalaldehyde, 1,3,5-tricarboxyphenyl, triacylphloroglucinol, 4,4′-biphenyldialdehyde, 1,3,5-tris(4-formylphenyl)benzene (TFPB), pyromellitic dianhydride, p-phenylenediamine, 1,3,5-tris(4-aminophenyl)benzene, and 4,4′-diaminobiphenyl.

[0009] The preparation method of the above-mentioned porphyrin-based polymer includes the following steps: (1) Dissolve the porphyrin compound and the R monomer group in an organic solvent; (2) The prepared organic solvent was placed in a hydrothermal reactor and reacted at 120 °C for 72 hours to obtain a precipitate. The precipitate was separated by filtration, washed with acetone, and dried under vacuum to obtain a porphyrin polymer.

[0010] A copper oxide@porphyrin-based polymer composite material, comprising copper oxide and the porphyrin-based polymer.

[0011] The preparation method of the above-mentioned copper oxide@porphyrin-based polymer composite material includes the following steps: (1) Dissolve the porphyrin-based polymer and copper oxide in an organic solvent; (2) The prepared organic solution was placed in a hydrothermal reactor and reacted at 120 °C for 24 hours to obtain a precipitate. The precipitate was separated by filtration, washed with acetone and ethanol in sequence, and dried under vacuum to obtain a copper oxide@porphyrin-based polymer composite material.

[0012] The copper oxide is one of copper oxide and cuprous oxide, or a combination thereof.

[0013] A method for preparing ethylene oxide includes the following steps: using oxygen, water, and carbon dioxide as raw materials, and a copper oxide@porphyrin-based polymer composite material as a catalyst, with the catalyst added at an amount of 0.02%–2.0 mol% of the raw materials, and controlling the reaction temperature at 20–150 °C and the reaction pressure at 0.05–2.0 MPa, the catalytic reaction is carried out under light and electrolysis conditions to obtain ethylene oxide. The light irradiation is 150 W, a full-spectrum light source; the electrolysis environment refers to electrolysis at -1.5 V relative to a standard hydrogen electrode.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses carbon dioxide and oxygen, which are cleaner, safer, more widely available, and cheaper, as raw materials, avoiding problems such as equipment corrosion and safety issues caused by the chlorohydrin method.

[0015] 2. This invention uses low temperature and normal pressure and green energy such as photoelectric power, thus avoiding problems such as high temperature, high pressure and high energy consumption in the reaction process.

[0016] 3. The process of the present invention is simple, the product selectivity is high, and the product is easy to separate. Attached Figure Description

[0017] Figure 1 The infrared spectrum of the porphyrin-based polymer; Figure 2 Powder X-ray diffraction pattern of porphyrin-based polymer; Figure 3 This is the solid-state carbon NMR spectrum of the porphyrin-based polymer; Figure 4 The 1H NMR spectrum of ethylene oxide ( 1 HNMR). Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments. Examples 1 and 2 are the preparation process of the catalyst, and Examples 3 to 10 are the preparation process of ethylene oxide.

[0019] Example 1: 0.1 mmol pyromellitic dianhydride and 0.5 mmol tetrakis(4-aminophenyl)porphyrin were ultrasonically dissolved in 20 mL of N,N-dimethylformamide solution. The mixture was placed in a 100 mL hydrothermal reactor and reacted at 120°C for 72 hours, resulting in a black precipitate. This precipitate was separated by filtration, washed three times with acetone, and vacuum dried to obtain a black powdery solid, which was the porphyrin-based polymer (in general formula (I), M represents none, and R represents terephthalaldehyde), with a yield of 60%. The infrared spectrum of the obtained porphyrin-based polymer is shown below. Figure 1 As shown, the powder X-ray diffraction pattern of the obtained porphyrin-based polymer is as follows. Figure 2 As shown, the solid-state carbon NMR spectrum of the obtained porphyrin-based polymer is as follows. Figure 3 As shown. The structure of the obtained porphyrin-based polymer can be confirmed as shown in general formula (I).

[0020] Example 2: 0.1 mmol of the porphyrin-based polymer obtained in Example 1 was ultrasonically dissolved in 20 mL of mesitylene solution, followed by the addition of 0.02 mmol of cuprous oxide. The mixture was placed in a 100 mL hydrothermal reactor and reacted at 120°C for 24 hours, resulting in a dark brown precipitate. The precipitate was separated by filtration, washed three times sequentially with acetone and ethanol, and dried under vacuum to obtain a brown powdery solid, which is the copper oxide@porphyrin-based polymer catalyst with a yield of 35%.

[0021] Example 3: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.2 mol% copper oxide@porphyrin-based polymer catalyst (Example 2) (the copper oxide was cuprous oxide, M in general formula (I) was absent, and R was terephthalaldehyde). A mixed gas (O2:CO2 = 1:1) was introduced at 1.0 MPa, and the mixture was irradiated with a xenon lamp and stirred at 40 °C. After 3 h, 1H NMR spectroscopy showed that the yield of ethylene oxide was 54%, with a selectivity of 90%. The 1H NMR spectrum of the obtained ethylene oxide product is shown below. Figure 4 As shown, this proves that ethylene oxide was indeed synthesized.

[0022] Example 4: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.05 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, except that cuprous oxide was replaced with copper oxide, M in general formula (I) is Fe, and R is 2,5-dimethoxy-terephthalaldehyde). A mixed gas of 1.5 MPa (O2:CO2=1:2) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 45 °C. After 3 h, the yield of ethylene oxide was 48% and the selectivity was 85% as detected by 1H NMR.

[0023] Example 5: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.1 mol% copper oxide@porphyrin-based polymer catalyst (referring to Example 2, except that cuprous oxide was replaced with copper oxide, and M in general formula (I) was Zn, and R was 1,3,5-tricarboxyphenyl). A mixed gas of 0.05 MPa (O2:CO2=1:2) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 60 °C. After 3 h, the yield of ethylene oxide was 52% and the selectivity was 95% as detected by 1H NMR.

[0024] Example 6: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.4 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, copper oxide is cuprous oxide, M in general formula (I) is Co, and R is p-triacyl-resorcinol). A mixed gas of 2.0 MPa (O2:CO2=1:1) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 55 °C. After 3 h, the yield of ethylene oxide was 64% and the selectivity was 94% as detected by 1H NMR.

[0025] Example 7: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.25 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, copper oxide is copper oxide, M in general formula (I) is Ni, and R is 4,4′-biphenyldicarboxaldehyde). A mixed gas of 1.0 MPa (O2:CO2=1:1) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 50 °C. After 3 h, the yield of ethylene oxide was 65% and the selectivity was 92% as detected by 1H NMR.

[0026] Example 8: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.2 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, copper oxide is cuprous oxide, M in general formula (I) is Cu, R is 1,3,5-tris(4-formylphenyl)benzene (TFPB)), and a mixed gas (O2:CO2=1:2) was introduced at 2.0 MPa. The cell was then irradiated with a xenon lamp at 45 °C. o The reaction was carried out under C with stirring. After 3 hours, the yield of ethylene oxide was 55% and the selectivity was 97% as determined by 1H NMR.

[0027] Example 9: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.3 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, where the copper oxide is cuprous oxide, M in general formula (I) is Ni, and R is pyromellitic dianhydride). A mixed gas of 0.5 MPa (O2:CO2=1:1) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 50 °C. After 3 h, the yield of ethylene oxide was 44% and the selectivity was 88% as detected by 1H NMR.

[0028] Example 10: In an electrolytic cell containing 10 mL of KHCO3 solution, an electrode was prepared using 0.25 mol% copper oxide@porphyrin-based polymer catalyst (refer to Example 2, copper oxide is copper oxide, M in general formula (I) is Mg, and R is p-phenylenediamine). A mixed gas of 1.5 MPa (O2:CO2=1:2) was introduced, and the mixture was irradiated with a xenon lamp and stirred at 60 °C. After 3 h, the yield of ethylene oxide was 31% and the selectivity was 80% as detected by 1H NMR.

Claims

1. A porphyrin-based polymer having the structure shown in general formula (I), wherein M in general formula (I) is one of the following: Fe, Zn, Co, Mn, Cu, Ni, and Mg, and R is a monomer group selected from terephthalaldehyde, 2,5-dimethoxyterephthalaldehyde, 1,3,5-tricarboxyphenyl, triacylphloroglucinol, 4,4′-biphenyldialdehyde, 1,3,5-tris(4-formylphenyl)benzene, pyromellitic dianhydride, p-phenylenediamine, 1,3,5-tris(4-aminophenyl)benzene, and 4,4′-diaminobiphenyl; 。 2. The method for preparing the porphyrin-based polymer according to claim 1, characterized in that... Includes the following steps: (1) Dissolve the porphyrin compound and the R monomer group in an organic solvent; (2) The prepared organic solvent was placed in a hydrothermal reactor and reacted at 120 °C for 72 hours to obtain a precipitate. The precipitate was separated by filtration, washed with acetone, and dried under vacuum to obtain a porphyrin polymer.

3. A copper oxide@porphyrin-based polymer composite material, characterized in that... It is composed of copper oxide and the porphyrin-based polymer as described in claim 1.

4. The method for preparing the copper oxide@porphyrin-based polymer composite material according to claim 3, characterized in that... Includes the following steps: (1) Dissolve the porphyrin-based polymer and copper oxide in an organic solvent; (2) The prepared organic solution was placed in a hydrothermal reactor and reacted at 120 °C for 24 hours to obtain a precipitate. The precipitate was separated by filtration, washed with acetone and ethanol in sequence, and dried under vacuum to obtain a copper oxide@porphyrin-based polymer composite material.

5. The preparation method according to claim 4, characterized in that... The copper oxide is one of copper oxide and cuprous oxide or a combination thereof.

6. A method for preparing ethylene oxide, characterized in that... The process includes the following steps: using oxygen, water, and carbon dioxide as raw materials, and copper oxide@porphyrin-based polymer composite material as catalyst, with the amount of catalyst added being 0.02% to 2.0 mol% of the raw materials, and controlling the reaction temperature at 20 to 150 °C and the reaction pressure at 0.05 to 2.0 MPa, the catalytic reaction is carried out in a light and electrolysis environment to obtain ethylene oxide.

7. The preparation method according to claim 6, characterized in that, The illumination is 150 W, a full-spectrum light source; the electrolysis environment refers to electrolysis at -1.5 V relative to the standard hydrogen electrode.

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