Benzene ring-containing compounds, methods of making and using the same
By preparing and applying compounds containing benzene rings as photocatalysts, the problems of poor selectivity and low oxygen activation efficiency of existing photocatalysts have been solved, achieving high efficiency, selectivity and safety in aldehyde oxidation reactions, which are suitable for industrial production.
Patent Information
- Application Number
- CN202411729236.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing photocatalysts exhibit poor selectivity in the isooctaldehyde oxidation reaction and low oxygen activation efficiency, resulting in long reaction times and making them unsuitable for industrial production.
A benzene ring-containing compound was used as a photocatalyst. It was prepared by substitution reaction and then contacted with aldehydes under light conditions. The photocatalytic oxidation of aldehydes to produce acid was carried out using a blue LED lamp, and an oxygen-containing gas was used for the reaction.
It improves the oxidation rate and selectivity of aldehydes, shortens the reaction time, is suitable for industrial production, and can be carried out under air conditions, ensuring high safety.
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Figure CN122102951A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalysis, specifically relating to a compound containing a benzene ring, its preparation method, and its application. Background Technology
[0002] 2-Ethylhexanoic acid, also known as isooctanoic acid, is an important fine chemical organic product. Its salts are widely used in coating drying agents, catalysts for polymer products, and stabilizers. The main industrial synthesis methods for isooctanoic acid include the isooctyl alcohol oxidation method and the aldehyde oxidation method. The aldehyde oxidation method uses n-butyraldehyde as a raw material, which undergoes condensation and dehydration to produce 2-ethylhexenal, which is then hydrogenated to obtain isooctaldehyde (also known as 2-ethylhexanal), and finally oxidized to obtain isooctanoic acid. This process has reliable raw material sources and is a continuous, fully enclosed process, making it easy to scale up production.
[0003] The oxidation of isooctaldehyde primarily utilizes alkaline catalysts, which struggle to activate oxygen to generate oxygen free radicals, resulting in a slow initial reaction rate and long reaction time. Photocatalysis can achieve efficient oxygen activation and shorten the reaction time. However, existing photocatalysts exhibit poor selectivity in the photocatalytic oxidation of isooctaldehyde. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a new method for photocatalytic oxidation of aldehydes to produce acids, which can achieve efficient activation of oxygen, shorten reaction time, and has excellent selectivity, making it suitable for industrial production.
[0005] To achieve the above objectives, the first aspect of the present invention provides a compound containing a benzene ring, the general structural formula of which is shown in formula (1):
[0006]
[0007] In this context, R and R' are each independently an alkyl group having 1-10 carbon atoms and may be the same or different.
[0008] The second aspect of the present invention provides a method for preparing the above-mentioned compound, comprising the following steps: contacting the compound represented by formula (2), an alkaline substance, and the compound represented by formula (3) to carry out a substitution reaction;
[0009]
[0010] A third aspect of this invention provides the application of compounds containing benzene rings in photocatalytic oxidation.
[0011] The fourth aspect of the present invention provides a method for preparing an acid by oxidizing an aldehyde, the method comprising: irradiating the aldehyde with light in an oxygen-containing gas in the presence of the photocatalyst described in formula (1).
[0012] Through the above technical solution, the present invention has achieved at least the following beneficial effects:
[0013] (1) The compounds of the present invention have excellent activity, which can accelerate the oxidation rate of aldehydes and improve the reaction selectivity. They also have excellent solubility in solvents (such as isooctanoic acid) used in the oxidation of aldehydes to prepare acids.
[0014] (2) The aldehyde oxidation reaction conditions of the present invention are mild, can be carried out under air conditions, are highly safe, and are suitable for industrial scale-up. Detailed Implementation
[0015] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0016] To achieve the above objectives, the first aspect of the present invention provides a compound containing a benzene ring, the structure of which is shown in formula (1):
[0017]
[0018] Where, X, X 1 X 2 X 3 Each is an independent halogen atom, and R and R' are each an alkyl group with 1-10 carbon atoms (preferably 4-9, more preferably 6-8) and are the same or different (that is, R on the four benzene rings are the same or different, and R' on the four benzene rings are the same or different).
[0019] In this invention, the alkyl group can be a straight-chain alkyl group or a branched alkyl group, preferably a straight-chain alkyl group, and more preferably, R and R' are each independently n-hexyl, n-heptyl and n-octyl.
[0020] Preferably, R = R'.
[0021] Preferably, X = X 1 =X 2 =X 3 .
[0022] In this invention, the halogen atom is preferably a fluorine atom.
[0023] In this invention, the R and R' substitutions on the benzene ring can be 1-5, preferably R and R' are located at the para position of the amino group on the benzene ring, that is, the structure of the compound is preferably as shown in formula (1a):
[0024]
[0025] The second aspect of the present invention provides a method for preparing the (above) compound, comprising the following steps: contacting the compound of formula (2), an alkaline substance, and the compound of formula (3) to carry out a substitution reaction;
[0026]
[0027] In equations (2) and (3), X and X 1 X 2 X 3 R and R' are as described above. Accordingly, in a preferred case, the structure of the compound represented by formula (3) is as shown in formula (3a):
[0028]
[0029] In the preparation method of the present invention, the molar ratio of formula (2) to formula (3) can be 1:4-6, preferably 1:4.5-5.5.
[0030] In the preparation method of the present invention, the alkaline substance can be a common substance that is alkaline in the reaction system, preferably a hydride and / or a tert-butoxide salt, more preferably at least one of sodium hydride, lithium hydride, potassium hydride, sodium tert-butoxide, potassium tert-butoxide and lithium tert-butoxide; and even more preferably sodium hydride.
[0031] In the preparation method of the present invention, the molar ratio of alkaline substance to formula (2) can be 4-8:1; preferably 5-6:1.
[0032] In the preparation method of the present invention, the contact is carried out in a reaction solvent, which can be a solvent commonly used in the art that can dissolve the above-mentioned reaction substrate. Preferably, the reaction solvent is a polar aprotic solvent, more preferably at least one of tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide, and N,N-dimethylformamide.
[0033] In the preparation method of the present invention, the amount of formula (2) can be 0.5-10 mol relative to each liter of reaction solvent, preferably 1-5 mol.
[0034] In the preparation method of the present invention, preferably, the contact conditions include: a temperature of 10-50°C, more preferably 20-30°C or room temperature.
[0035] In the preparation method of the present invention, preferably, the contact conditions include a time of 8-15 hours, more preferably 10-12 hours.
[0036] In the preparation method of the present invention, in order to further improve the conversion rate and yield of the product, the preferred contact method is to first contact the alkaline substance with the compound shown in formula (3), and then introduce the compound shown in formula (2) for a second contact.
[0037] More preferably, the temperature of the first contact is 0-20°C, more preferably 0-5°C. Preferably, the duration of the first contact is 10-50 min, more preferably 25-35 min.
[0038] More preferably, the temperature of the second contact is 10-50°C, more preferably 20-30°C or room temperature. Preferably, the duration of the first contact is 8-15 hours, more preferably 10-12 hours.
[0039] The preparation method of the present invention may further include: quenching with water after the reaction is completed, concentrating under reduced pressure, and then obtaining the target compound by column chromatography.
[0040] The third aspect of the present invention also provides the application of the above-mentioned benzene ring-containing compounds in photocatalytic oxidation (especially photocatalytic oxidation of aldehydes such as 2-ethylhexanal)).
[0041] A fourth aspect of the present invention provides a method for preparing an acid by oxidizing an aldehyde, the method comprising: irradiating the aldehyde in an oxygen-containing gas in the presence of a photocatalyst, wherein the photocatalyst is the aforementioned compound containing a benzene ring.
[0042] In this invention, the aldehyde is irradiated in the form of an aldehyde solution. Preferably, the mass fraction of aldehyde in the aldehyde solution is 20-50 wt%, more preferably 30-40 wt%. Preferably, the solvent in the aldehyde solution can be a solvent commonly used in the art for the photocatalytic oxidation of aldehydes. However, in order to further avoid solvent residue and improve product purity, the solvent in the aldehyde solution is preferably the acid corresponding to the aldehyde (the oxidation product of the aldehyde). For example, when the aldehyde is isooctaldehyde, the corresponding solvent isooctanoic acid (2-ethylhexanoic acid).
[0043] In the acid preparation method of the present invention, the molar amount of the photocatalyst is 100-1000 ppm relative to each mole of aldehyde; preferably 300-500 ppm.
[0044] In the acid preparation method of the present invention, the light source for illumination is blue light (a light source generated by a blue LED lamp, with a wavelength of 400-500nm) and a power of 10-50W.
[0045] In the acid preparation method of the present invention, the oxygen-containing gas can be a gas with an oxygen content greater than 20% by volume, and the oxygen-containing gas can be pure oxygen, air, or an oxygen-enriched gas composed of an inert gas (preferably nitrogen) and oxygen, preferably air.
[0046] In the acid preparation method of the present invention, the light irradiation is preferably carried out at room temperature.
[0047] In the acid preparation method of the present invention, the irradiation time can be 1-5 hours, preferably 2-4 hours.
[0048] In this invention, the aldehyde can be a common aldehyde in the art, such as C5-C9 aldehydes, preferably at least one of isooctaldehyde (2-ethylhexanal), n-nonanal, n-octanal, n-heptanal and 3,5,5-trimethylhexanal.
[0049] The present invention will be described in detail below through embodiments.
[0050] Unless otherwise specified, all reagents and materials used in the following examples and comparative examples are commercially available. 4,4′-Dimethyldiphenylamine, bis(4-n-hexylphenyl)amine, bis(4-n-octylphenyl)amine, and 2,4,5,6-tetrafluoroisophthalonitrile were purchased from Anegie Chemicals; sodium hydride was dispersed in mineral oil; yield = (actual yield of target product (acid) / theoretical yield of target product (acid)) × 100%; aldehyde conversion = (amount of aldehyde reacted / initial amount of aldehyde) × 100%; acid selectivity = (acid yield / aldehyde conversion) × 100%.
[0051] Preparation Example 1
[0052] Tri-tert-butylphosphine tetrafluoroborate (1 mmol), tris(dibenzylacetone)dipalladium (0.25 mmol), and potassium tert-butoxide (60 mmol) were dissolved in nitrogen to remove oxygen. Toluene (200 mL), 4-n-heptylaniline (50 mmol), and 4-n-heptylbromobenzene (51 mmol) were then added. The mixture was stirred at room temperature for 10 min. The temperature was then raised to 110 °C and reacted for 12 h. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow oily compound of formula (3). The mass of the obtained compound was 15.78 g, with a yield of 86.4%.
[0053] The reaction process is as follows:
[0054]
[0055] The product obtained in this preparation example was characterized by NMR, and the results are as follows: 1¹H NMR (500MHz, Chloroform) δ 7.06 (d, J = 8.1Hz, 4H), 6.97 (d, J = 8.0Hz, 4H), 2.54 (t, J = 7.4Hz, 4H), 1.62-1.55 (m, 4H), 1.39-1.27 (m, 16H), 0.89 (t, J = 6.8Hz, 6H). The NMR results show that the product structure is as shown in equation (3), where R and R' are both n-heptyl groups.
[0056] Preparation Example 2
[0057] Tri-tert-butylphosphine tetrafluoroborate (1 mmol), tris(dibenzylacetone)dipalladium (0.25 mmol), and potassium tert-butoxide (60 mmol) were dissolved in nitrogen to remove oxygen. Toluene (200 mL), 4-n-decylaniline (50 mmol), and 4-n-decylbromobenzene (53 mmol) were then added. The mixture was stirred at room temperature for 10 min. The temperature was then raised to 120 °C and reacted for 12 h. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow solid compound of formula (3). The mass of the obtained compound was 11.67 g, with a yield of 51.8%.
[0058] The reaction process is as follows:
[0059]
[0060] The product obtained in this preparation example was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.06 (d, J = 8.1Hz, 4H), 6.97 (d, J = 8.0Hz, 4H), 2.54 (t, J = 7.4Hz, 4H), 1.62-1.55 (m, 4H), 1.39-1.27 (m, 28H), 0.89 (t, J = 6.8Hz, 6H). The NMR results show that the product structure is as shown in equation (3), where R and R' are both n-decyl groups.
[0061] Preparation Example 3
[0062] 1.5 mmol of tri-tert-butylphosphine tetrafluoroborate, 0.5 mmol of tris(dibenzylacetone)dipalladium, and 60 mmol of potassium tert-butoxide were added after nitrogen purging to remove oxygen. Toluene (200 mL), 50 mmol of 3-n-hexylaniline, and 56 mmol of 3-n-hexylbromobenzene were then added. The mixture was stirred at room temperature for 10 min, then heated to 130 °C and reacted for 14 h. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, concentrated under reduced pressure, and then subjected to column chromatography to obtain a yellow liquid compound of formula (3). The mass of the obtained compound was 5.27 g, with a yield of 31.2%.
[0063] The reaction process is as follows:
[0064]
[0065] The product obtained in this preparation example was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, DMSO-d₆) δ 7.49 (dt, J = 15.0, 3.1Hz, 2H), 7.28 (t, J = 3.0Hz, 2H), 7.19 (t, J = 15.0Hz, 2H), 6.88 (dt, J = 15.0, 3.0Hz, 2H), 2.64 (t, J = 15.7Hz, 4H), 1.70-1.53 (m, 4H), 1.38-1.21 (m, 12H), 0.95-0.84 (m, 6H). The NMR results show that the product structure is as shown in equation (3), where R and R' are both n-hexyl groups.
[0066] Example 1
[0067] 5 mL of tetrahydrofuran was added to bis(4-hexylphenyl)amine (22.5 mmol), the mixture was purged with nitrogen to remove oxygen, and then cooled to 0 °C. 60% sodium hydride (25 mmol) was slowly added, and the reaction was maintained at 0 °C for 30 min. Then 2,4,5,6-tetrafluoroisophthalonitrile (5 mmol) was added, and the mixture was heated to 25 °C and reacted for 10 h. After the reaction was completed, excess sodium hydride was quenched with water, and the mixture was concentrated under reduced pressure and then subjected to column chromatography to obtain 5.56 g of yellow solid, with a yield of 75.6%.
[0068] The reaction process is as follows:
[0069]
[0070] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.28-7.15 (m, 16H), 7.09-6.99 (m, 12H), 6.92-6.85 (m, 4H), 2.69-2.46 (m, 16H), 1.72-1.23 (m, 64H), 0.96-0.85 (m, 24H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the para position of the amino group, which is n-hexyl.
[0071] Example 2
[0072] Bis(4-n-heptylphenyl)amine (Preparation Example 1, 27.5 mmol) was dissolved in 4 mL of tetrahydrofuran. After purging with nitrogen to remove oxygen, the solution was cooled to 0 °C, and 60% sodium hydride (30 mmol) was slowly added. The reaction was maintained at 0 °C for 30 min. Then, 2,4,5,6-tetrafluoroisophthalonitrile (5 mmol) was added, and the temperature was raised to 30 °C for 12 h. After the reaction was completed, excess sodium hydride was quenched with water, and the solution was concentrated under reduced pressure. Column chromatography was then performed to obtain 5.68 g of a yellow solid, with a yield of 71.8%.
[0073] The reaction process is as shown in Example 1.
[0074] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.30-7.15 (m, 16H), 7.06-6.95 (m, 12H), 6.82-6.55 (m, 4H), 2.64-2.41 (m, 16H), 1.70-1.23 (m, 80H), 1.01-0.83 (m, 24H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the para position of the amino group, which is n-heptyl.
[0075] Example 3
[0076] Bis(4-n-octylphenyl)amine (25 mmol) was dissolved in 1 mL of tetrahydrofuran. After purging with nitrogen to remove oxygen, the solution was cooled to 0 °C, and 60% sodium hydride (27.5 mmol) was slowly added. The reaction was maintained at 0 °C for 30 min. Then, 2,4,5,6-tetrafluoroisophthalonitrile (5 mmol) was added, and the temperature was raised to 20 °C for 11 h. After the reaction was completed, excess sodium hydride was quenched with water, and the solution was concentrated under reduced pressure. Column chromatography was then performed to obtain 6.30 g of a yellow solid, with a yield of 74.4%.
[0077] The reaction process is as shown in Example 1.
[0078] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.21-7.05 (m, 16H), 7.01-6.85 (m, 12H), 6.72-6.55 (m, 4H), 2.71-2.52 (m, 16H), 1.75-1.13 (m, 96H), 1.05-0.78 (m, 24H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the para position of the amino group, which is n-octyl.
[0079] Example 4
[0080] 20 mmol of 4,4′-dimethyldiphenylamine was dissolved in 1 mL of tetrahydrofuran. After purging with nitrogen to remove oxygen, the solution was cooled to 0 °C, and 25.5 mmol of 60% sodium hydride was slowly added. The reaction was maintained at 0 °C for 30 min. Then, 5 mmol of 2,4,5,6-tetrafluoroisophthalonitrile was added, and the temperature was raised to 20 °C for 11 h. After the reaction was completed, excess sodium hydride was quenched with water, and the solution was concentrated under reduced pressure. Column chromatography was then performed to obtain 3.84 g of a yellow solid, with a yield of 84.4%.
[0081] The reaction process is as shown in Example 1.
[0082] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.08-7.02 (m, 8H), 6.92-6.85 (m, 16H), 6.72-6.63 (m, 8H), 2.28 (s, 6H), 2.17 (s, 12H), 2.01 (s, 6H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the para position of the amino group, indicating that it is a methyl group.
[0083] Example 5
[0084] Bis(4-n-decylphenyl)amine (Preparation Example 2, 28 mmol) was dissolved in 5 mL of tetrahydrofuran. After purging with nitrogen to remove oxygen, the solution was cooled to 0 °C, and 60% sodium hydride (30 mmol) was slowly added. The reaction was maintained at 0 °C for 30 min. Then, 2,4,5,6-tetrafluoroisophthalonitrile (5 mmol) was added, and the temperature was raised to 20 °C for 12 h. After the reaction was completed, excess sodium hydride was quenched with water, and the solution was concentrated under reduced pressure. Column chromatography was then performed to obtain 4.14 g of a brown solid, with a yield of 43.1%.
[0085] The reaction process is as shown in Example 1.
[0086] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.12-7.06 (m, 16H), 7.01-6.85 (m, 16H), 2.71-2.60 (m, 16H), 1.75-1.18 (m, 128H), 0.98-0.75 (m, 24H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the para position of the amino group, which is n-decyl.
[0087] Example 6
[0088] Bis(3-n-hexylphenyl)amine (Preparation Example 3, 11 mmol) was dissolved in 5 mL of tetrahydrofuran. After purging with nitrogen to remove oxygen, the solution was cooled to 0 °C, and 60% sodium hydride (12 mmol) was slowly added. The reaction was maintained at 0 °C for 30 min. Then, 2,4,5,6-tetrafluoroisophthalonitrile (2 mmol) was added, and the temperature was raised to 20 °C for 12 h. After the reaction was completed, excess sodium hydride was quenched with water, and the solution was concentrated under reduced pressure. Column chromatography was then performed to obtain 0.64 g of a yellow solid, with a yield of 21.8%.
[0089] The reaction process is as shown in Example 1.
[0090] The product obtained in this embodiment was characterized by NMR, and the results are as follows: 1 ¹H NMR (500MHz, Chloroform) δ 7.33-7.14 (m, 16H), 7.00-6.94 (m, 8H), 6.92-6.85 (m, 8H), 2.64 (t, J = 15.6Hz, 16H), 1.65-1.24 (m, 64H), 0.89 (t, J = 13.0Hz, 24H). The NMR results show that the product structure is as shown in formula (1), where R and R' are both on the benzene ring and located at the meta position of the amino group, representing a n-hexyl group.
[0091] Test Example 1
[0092] A 100 mL Schlenk tube was filled with 100 mmol of 2-ethylhexanol, a 30% (w / w) solution of 2-ethylhexanoic acid, and a photocatalyst (Example 1, 0.03 mmol). The reaction was carried out under air irradiation with a 10 W blue LED light, and the reaction temperature was maintained at 23-27 °C by cooling water. After 2 h of reaction, the reaction products were analyzed by gas chromatography. The conversion rate of 2-ethylhexanol was calculated to be 99.2%, the selectivity of 2-ethylhexanoic acid was 99.0%, and the yield was 98.2%.
[0093] Comparative Test Case 1
[0094] The method was the same as in Test Example 1, except that no photocatalyst was added. Calculations showed a conversion of 90.2% for 2-ethylhexanal, a selectivity of 76.1% for 2-ethylhexanoic acid, and a yield of 68.6%.
[0095] Test Example 2
[0096] A 100 mL Schlenk tube was filled with 100 mmol of 2-ethylhexanol, a 40% (w / w) solution of 2-ethylhexanoic acid, and a photocatalyst (Example 2, 0.04 mmol). The reaction was carried out under air irradiation with a 10 W blue LED light, and the reaction temperature was maintained at 23-27 °C by cooling water. After 4 h of reaction, the reaction products were analyzed by gas chromatography. The conversion rate of 2-ethylhexanol was calculated to be 98.8%, the selectivity of 2-ethylhexanoic acid was 99.5%, and the yield was 98.3%.
[0097] Test Example 3
[0098] A 100 mL Schlenk tube was filled with 100 mmol of 2-ethylhexanol, a 40% (w / w) solution of 2-ethylhexanoic acid, and a photocatalyst (Example 3, 0.05 mmol). The reaction was carried out under air irradiation with a 10 W blue LED light, and the reaction temperature was maintained at 23-27 °C by cooling water. After 3 h of reaction, the reaction products were analyzed by gas chromatography. The conversion rate of 2-ethylhexanol was calculated to be 99.4%, the selectivity of 2-ethylhexanoic acid was 99.9%, and the yield was 99.3%.
[0099] Test Example 4
[0100] The method was the same as in Test Example 1, except that the photocatalyst was replaced with the structure shown in Formula (1), but R and R' were both methyl (Example 4). The conversion of 2-ethylhexanal was calculated to be 92.5%, the selectivity of 2-ethylhexanoic acid was 85.7%, and the yield was 79.3%.
[0101] Test Example 5
[0102] The method was the same as in Test Example 1, except that the photocatalyst was replaced, resulting in a structure as shown in Formula (1), but with R and R' both being n-decyl (Example 5). Calculations showed a conversion of 89.3% for 2-ethylhexanal, a selectivity of 85.3% for 2-ethylhexanoic acid, and a yield of 76.2%.
[0103] Test Example 6
[0104] The method was the same as in Test Example 1, except that the photocatalyst was replaced, resulting in a structure as shown in Formula (1) but with R and R' in the meta position (Example 6). Calculations showed a conversion of 97.5% for 2-ethylhexanal, a selectivity of 98.6% for 2-ethylhexanoic acid, and a yield of 96.1%.
[0105] Test Example 7
[0106] A 100 mL Schlenk tube was filled with 100 mmol of 3,5,5-trimethylhexanal and a 40% (w / w) solution of 3,5,5-trimethylhexanoic acid, along with a photocatalyst (Example 2, 0.03 mmol). The reaction was carried out under air irradiation with a 10 W blue LED light, and the reaction temperature was maintained at 23-27 °C using cooling water. After 4 h of reaction, the reaction products were analyzed by gas chromatography. The conversion rate of 3,5,5-trimethylhexanal was 99.8%, the selectivity of 3,5,5-trimethylhexanoic acid was 99.3%, and the yield was 99.1%.
[0107] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A compound containing a benzene ring, characterized in that, The structure of the compound is shown in formula (1): In this context, R and R' are each independently an alkyl group having 1-10 carbon atoms and may be the same or different.
2. The compound according to claim 1, wherein, R = R'; And / or, R and R' are each independently 4-9 alkyl groups, preferably n-hexyl, n-heptyl or n-octyl; And / or, R and R' are located at the para position of the amino group on the benzene ring.
3. A method for preparing a compound containing a benzene ring, characterized in that, The method includes: contacting the compound shown in formula (2), an alkaline substance, and the compound shown in formula (3) to carry out a substitution reaction; Among them, X, X 1 X 2 X 3 Each is an independent halogen atom, and R and R' are each an independent alkyl group having 1-10 carbon atoms and may be the same or different.
4. The preparation method according to claim 3, wherein, The molar ratio of the compound shown in formula (2) to the compound shown in formula (3) is 1:4-6, preferably 1:4.5-5.5; And / or, R = R'; And / or, R and R' are each independently 4-9 alkyl groups, preferably n-hexyl, n-heptyl or n-octyl; And / or, X = X 1 =X 2 =X 3 ; And / or, X, X 1 X 2 X 3 All are fluorine atoms.
5. The preparation method according to claim 3, wherein, The alkaline substance is at least one selected from sodium hydride, lithium hydride, potassium hydride, sodium tert-butoxide, potassium tert-butoxide, and lithium tert-butoxide; preferably sodium hydride.
6. The preparation method according to any one of claims 3-5, wherein, The molar ratio of the alkaline substance to the compound shown in formula (2) is 4-8:1; preferably 5-6:
1.
7. The preparation method according to claim 3, wherein, The contact is carried out in a reaction solvent, which is a polar aprotic solvent, preferably at least one of tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide and N,N-dimethylformamide; And / or, the contact conditions include: a temperature of 10-50°C, preferably 20-30°C; and a time of 8-15 hours, preferably 10-12 hours.
8. The application of the benzene ring-containing compound according to claim 1 or 2 in photocatalytic oxidation.
9. A method for preparing an acid by aldehyde oxidation, characterized in that, The method includes: irradiating an aldehyde in an oxygen-containing gas in the presence of a photocatalyst, wherein the photocatalyst is a benzene-ring-containing compound as described in claim 1 or 2.
10. The method according to claim 9, wherein, The aldehyde is irradiated in the form of an aldehyde solution, wherein the mass fraction of aldehyde in the aldehyde solution is 20-50 wt%, preferably 30-40 wt%. Preferably, the solvent in the aldehyde solution is an acid, the oxidation product of the aldehyde.
11. The method according to claim 9, wherein, The molar amount of the photocatalyst relative to each mole of aldehyde is 100-1000 ppm; preferably 300-500 ppm. And / or, the aldehyde is a C5-C9 aldehyde, preferably at least one of 2-ethylhexanal, n-nonanal, n-octanal, n-heptanal and 3,5,5-trimethylhexanal.
12. The method according to claim 9, wherein, The oxygen-containing gas is air; And / or, the light source is blue light with a power of 10-50W.