Process for the preparation of substituted phenylene aromatic diesters and their use in the preparation of catalysts

Abstract

The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of substituted phenylene aromatic diester and application thereof in preparation of a catalyst. The preparation method comprises the following steps: first, 2-hydroxy-3-methylbenzaldehyde is reacted with meta-chloro peroxybenzoic acid and sodium ethoxide to generate 3-methyl catechol; then, 3-methyl catechol is reacted with isobutene by taking triisobutyl aluminum as a catalyst to generate 5-tert-butyl-3-methyl catechol; finally, 5-tert-butyl-3-methyl catechol is reacted with triethylamine and benzoyl chloride, and the substituted phenylene aromatic diester is obtained. The application provides a novel preparation method of the substituted phenylene aromatic diester, the dependence on metal reagents in a traditional reduction method is avoided by selecting specific alkaline reagents and catalysts, the yield and purity of the substituted phenylene aromatic diester are greatly improved, the reaction condition is mild, the cost is low, and the method is suitable for large-scale preparation.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of a substituted phenylene aromatic diester and application thereof in catalyst preparation. Background Art

[0002] Substituted phenylene aromatic diesters are a class of compounds with a phenylene (1,2-phenylene, 1,3-phenylene, or 1,4-phenylene) core skeleton and aromatic carboxylate groups attached to either end. Their aromatic rings are substituted with groups such as alkyl, halogen, and alkoxy groups. A typical example is 3-methyl-5-tert-butyl-1,2-benzenediol benzoate (BMPD). Ziegler-Natta catalysts containing BMPD as an internal electron donor exhibit high catalytic activity and selectivity in polymerization processes, enabling the preparation of olefin polymers with a wide molecular weight distribution.

[0003] Chinese invention patent publication number CN104860826A provides a four-step synthesis pathway for BMPD from o-cresol via halogenation, hydrolysis, alkylation, and benzoylation. However, this invention uses a traditional catalyst, inorganic acid (such as concentrated sulfuric acid), which presents problems of equipment corrosion and side reactions, and the overall yield and purity of the BMPD produced are low.

[0004] In view of this, there is an urgent need in the art to provide a green and efficient method for the large-scale production of high-yield and high-purity substituted phenylene aromatic diesters under mild reaction conditions. Summary of the Invention

[0005] The present invention aims to solve the problems in the prior art and provides a preparation method of a substituted phenylene aromatic diester and an application of the same in catalyst preparation.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for preparing a substituted phenylene aromatic diester, comprising the following steps:

[0008] (1) 2-Hydroxy-3-methylbenzaldehyde reacts with m-chloroperbenzoic acid and sodium ethoxide to produce 3-methylcatechol;

[0009] (2) Using triisobutylaluminum as a catalyst, 3-methylcatechol reacts with isobutylene to produce 5-tert-butyl-3-methylcatechol;

[0010] (3) Finally, 5-tert-butyl-3-methylcatechol is reacted with triethylamine and benzoyl chloride to obtain the product.

[0011] Preferably, the molar ratio of 2-hydroxy-3-methylbenzaldehyde, m-chloroperbenzoic acid and sodium ethoxide in step (1) is 1:1-2:2-4.

[0012] Preferably, the reaction temperature in step (1) is 20-25°C, the reaction time is 2-3 h, and acetonitrile is used as the reaction solvent.

[0013] Preferably, in step (1), the progress of the reaction is monitored by TLC, and the developing solvent of TLC is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2-4:1. After the reaction is completed, post-treatment is also performed, and the post-treatment comprises adding a sodium thiosulfate aqueous solution with a volume fraction of 10%-15% to the reaction solution, separating the liquids, combining the organic phases and drying.

[0014] Preferably, the molar ratio of 3-methylcatechol, isobutylene and triisobutylaluminum in step (2) is 1:2-3:0.05-0.1.

[0015] Preferably, in step (2), the reaction atmosphere is nitrogen or argon, the reaction temperature is 20-30°C, and the reaction time is 2-4 h. After the reaction is completed, the reaction solution needs to be washed with water to neutrality, separated, and the organic phases are combined, purified by column chromatography, and dried.

[0016] Preferably, the molar ratio of 5-tert-butyl-3-methylcatechol, triethylamine and benzoyl chloride in step (3) is 1:3.5-4.5:2.5-3.

[0017] Preferably, the reaction atmosphere in step (3) is nitrogen or argon, the reaction temperature is 20-30°C, the reaction time is 0.5-1.5 h, and the reaction solvent is dichloromethane.

[0018] Preferably, after the reaction in step (3) is completed, the liquid is separated, the organic phase is combined, the solvent is distilled off, and the product is purified by column chromatography and dried. The eluent for column chromatography purification is a mixture of petroleum ether and ethyl acetate in a volume ratio of 7-9:1.

[0019] Preferably, the preparation process of 2-hydroxy-3-methylbenzaldehyde in step (1) comprises: condensing o-cresol with paraformaldehyde to generate 2-hydroxy-3-methylbenzaldehyde.

[0020] The present invention also provides application of the preparation method in preparing a propylene polymerization catalyst.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a novel preparation method of substituted phenylene aromatic diesters. By selecting specific alkaline reagents and catalysts, the dependence of traditional reduction methods on metal reagents is avoided, the yield and purity of substituted phenylene aromatic diesters are greatly improved, and the reaction conditions are mild, the cost is low, and the method is suitable for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the H NMR spectrum of 2-hydroxy-3-methylbenzaldehyde.

[0024] Figure 2 This is the H NMR spectrum of 3-methylcatechol.

[0025] Figure 3 This is the H NMR spectrum of 5-tert-butyl-3-methylcatechol.

[0026] Figure 4 This is the H NMR spectrum of 3-methyl-5-tert-butyl-1,2-benzenediol benzoate.

[0027] It is worth noting that the unclear parts of the drawings do not affect the understanding of the technical solutions of the present invention by those skilled in the art. DETAILED DESCRIPTION

[0028] It is worth noting that the raw materials used in the present invention are all common commercially available products: paraformaldehyde, with a relative molecular weight of 30 g / mol; and concentrated hydrochloric acid, with a mass fraction of 38%.

[0029] Example 1

[0030] A method for preparing a substituted phenylene aromatic diester comprises the following steps:

[0031] (1) Add o-cresol (500 mmol), magnesium chloride (1500 mmol) and acetonitrile (1500 mL) to a three-necked flask and stir until dissolved. Then, add triethylamine (1925 mmol) dropwise at 10 °C. Stir for 15 min after the addition. Add paraformaldehyde (3500 mmol) in batches. Stir vigorously after each addition to ensure that the paraformaldehyde is evenly dispersed. React at 90 °C for 4 h. After the reaction is completed, cool to 25 °C, add ethyl acetate (500 mL) and concentrated hydrochloric acid (700 mL) to the reaction solution, adjust the pH to 2, continue stirring for 30 min, and then separate the liquids. Add ethyl acetate (1500 mL) to the aqueous phase, combine the organic phases, remove ethyl acetate and acetonitrile by rotary evaporation, and then dry over anhydrous sodium sulfate. Finally, add ethyl acetate for three times and recrystallize to obtain 2-hydroxy-3-methylbenzaldehyde (yield 92.6%, purity 97.5%). Its nuclear magnetic hydrogen spectrum is shown as follows: Figure 1 shown.

[0032] (2) Add 2-hydroxy-3-methylbenzaldehyde (463 mmol) and acetonitrile (1500 mL) prepared in step (1) to a three-necked flask, stir until completely dissolved, heat to 20 °C, add sodium ethoxide (1389 mmol) first, then add m-chloroperbenzoic acid (926 mmol) in batches, stir and react for 2 h, and monitor the disappearance of the substrate by TLC (developing solvent is petroleum ether: ethyl acetate = 3:1, v / v). After the reaction is completed, slowly add 10% volume fraction of sodium thiosulfate aqueous solution (1500 mL) to the reaction solution, separate the liquid, wash the organic phase with saturated brine twice, combine the organic phases, and dry over anhydrous magnesium sulfate to obtain 3-methylcatechol (yield 91.5%, purity 96.4%), the H NMR spectrum of which is shown as follows Figure 2 shown.

[0033] (3) Under nitrogen protection, 3-methylcatechol (423 mmol), triisobutylaluminum (33.84 mmol) and toluene (1000 mL) prepared in step (2) were added to a three-necked flask, heated to 30 °C, and isobutylene (1058 mmol) gas was introduced at a rate of 60 mL / min for 3 h. After the reaction, the reaction solution was washed with water until neutral, then separated, the organic phases were combined, concentrated under reduced pressure, and purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 10:1, v / v). The eluate was collected and dried to obtain 5-tert-butyl-3-methylcatechol (yield 95.7%, purity 93.7%). Its H NMR spectrum is shown as follows: Figure 3 shown.

[0034] (4) Under nitrogen protection and a temperature of 5°C, 5-tert-butyl-3-methylcatechol (405 mmol), triethylamine (1617 mmol), benzoyl chloride (1010 mmol) and dichloromethane (825 mL) prepared in step (3) were added to a four-necked flask, and the temperature was raised to 25°C for reaction for 1 h. After the reaction, the reaction solution was separated, the organic phase was combined, the dichloromethane was distilled off, and the product was purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 8:1, v / v). The eluate was collected and dried to obtain 3-methyl-5-tert-butyl-1,2-benzenediol benzoate (yield 98.6%, purity 99.1%). Its H NMR spectrum is shown in FIG. Figure 4 shown.

[0035] Example 2

[0036] A method for preparing a substituted phenylene aromatic diester comprises the following steps:

[0037] (1) Add o-cresol (500 mmol), magnesium chloride (1500 mmol) and acetonitrile (1500 mL) to a three-necked flask and stir until dissolved. Then, add triethylamine (1925 mmol) dropwise at 10 °C. Stir for 15 min after the addition. Add paraformaldehyde (3500 mmol) in batches. Stir vigorously after each addition to ensure that the paraformaldehyde is evenly dispersed. React at 90 °C for 4 h. After the reaction is completed, cool to 25 °C, add ethyl acetate (500 mL) and concentrated hydrochloric acid (700 mL) to the reaction solution, adjust the pH to 2, continue stirring for 30 min, and then separate the liquids. Add ethyl acetate (1500 mL) to the aqueous phase, combine the organic phases, remove ethyl acetate and acetonitrile by rotary evaporation, dry over anhydrous sodium sulfate, and finally add ethyl acetate for three times to obtain 2-hydroxy-3-methylbenzaldehyde (yield 92.6%, purity 97.5%).

[0038] (2) Add 2-hydroxy-3-methylbenzaldehyde (463 mmol) and acetonitrile (1500 mL) prepared in step (1) to a three-necked flask, stir until completely dissolved, heat to 25 °C, add sodium ethoxide (926 mmol) first, then add m-chloroperbenzoic acid (463 mmol) in batches, stir and react for 2 h, and monitor the disappearance of the substrate by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1, v / v). After the reaction is completed, slowly add 15% volume fraction of sodium thiosulfate aqueous solution (1200 mL) to the reaction solution, separate the liquid, wash the organic phase with saturated brine twice, combine the organic phases, and dry over anhydrous magnesium sulfate to obtain 3-methylcatechol (yield 90.8%, purity 95.7%).

[0039] (3) Under nitrogen protection, 3-methylcatechol (420 mmol), triisobutylaluminum (21 mmol), and toluene (1000 mL) prepared in step (2) were added to a three-necked flask, heated to 25 °C, and isobutylene (840 mmol) gas was introduced at a rate of 60 mL / min for 2 h. After the reaction, the reaction solution was washed with water until neutral, then separated, the organic phases were combined, concentrated under reduced pressure, and purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 10:1, v / v). The eluate was collected and dried to obtain 5-tert-butyl-3-methylcatechol (yield 94.8%, purity 91.5%).

[0040] (4) Under nitrogen protection and a temperature of 5°C, 5-tert-butyl-3-methylcatechol (398 mmol), triethylamine (1393 mmol), benzoyl chloride (995 mmol) and dichloromethane (800 mL) prepared in step (3) were added to a four-necked flask, and the temperature was raised to 20°C for reaction for 1.5 h. After the reaction, the reaction solution was separated, the organic phase was combined, and the dichloromethane was distilled off. The product was purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 7:1, v / v). The eluate was collected and dried to obtain 3-methyl-5-tert-butyl-1,2-benzenediol benzoate (yield 98.2%, purity 99.0%).

[0041] Example 3

[0042] (1) Add o-cresol (500 mmol), magnesium chloride (1500 mmol) and acetonitrile (1500 mL) to a three-necked flask and stir until dissolved. Then, add triethylamine (1925 mmol) dropwise at 10 °C. Stir for 15 min after the addition. Add paraformaldehyde (3500 mmol) in batches. Stir vigorously after each addition to ensure that the paraformaldehyde is evenly dispersed. React at 90 °C for 4 h. After the reaction is completed, cool to 25 °C, add ethyl acetate (500 mL) and concentrated hydrochloric acid (700 mL) to the reaction solution, adjust the pH to 2, continue stirring for 30 min, and then separate the liquids. Add ethyl acetate (1500 mL) to the aqueous phase, combine the organic phases, remove ethyl acetate and acetonitrile by rotary evaporation, dry over anhydrous sodium sulfate, and finally add ethyl acetate for three times to obtain 2-hydroxy-3-methylbenzaldehyde (yield 92.6%, purity 97.5%).

[0043] (2) Add 2-hydroxy-3-methylbenzaldehyde (463 mmol) and acetonitrile (1800 mL) prepared in step (1) to a three-necked flask, stir until completely dissolved, heat to 20 °C, add sodium ethoxide (1852 mmol) first, then add m-chloroperbenzoic acid (694 mmol) in batches, stir and react for 3 h, and monitor the disappearance of the substrate by TLC (developing solvent is petroleum ether: ethyl acetate = 4:1, v / v). After the reaction is completed, slowly add 15% volume fraction of sodium thiosulfate aqueous solution (1500 mL) to the reaction solution, separate the liquid, wash the organic phase with saturated brine twice, combine the organic phases, and dry over anhydrous magnesium sulfate to obtain 3-methylcatechol (yield 91.0%, purity 96.3%).

[0044] (3) Under nitrogen protection, 3-methylcatechol (421 mmol), triisobutylaluminum (42 mmol), and toluene (1200 mL) prepared in step (2) were added to a three-necked flask, heated to 20 °C, and isobutylene (1263 mmol) gas was introduced at a rate of 60 mL / min for 4 h. After the reaction, the reaction solution was washed with water until neutral, then separated, the organic phases were combined, concentrated under reduced pressure, and purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 10:1, v / v). The eluate was collected and dried to obtain 5-tert-butyl-3-methylcatechol (yield 95.3%, purity 92.9%).

[0045] (4) Under nitrogen protection and a temperature of 5°C, 5-tert-butyl-3-methylcatechol (401 mmol), triethylamine (1804 mmol), benzoyl chloride (1203 mmol) and dichloromethane (850 mL) prepared in step (3) were added to a four-necked flask, and the temperature was raised to 30°C for reaction for 0.5 h. After the reaction, the reaction solution was separated, the organic phase was combined, and the dichloromethane was distilled off. The product was purified by column chromatography (silica gel column, eluent: petroleum ether: ethyl acetate = 9:1, v / v). The eluate was collected and dried to obtain 3-methyl-5-tert-butyl-1,2-benzenediol benzoate (yield 98.4%, purity 99.3%).

[0046] Example 4

[0047] A method for preparing a Ziegler-Natta catalyst comprises the following steps:

[0048] (1) Anhydrous MgCl2 and propylene glycol were mixed in a mass ratio of 10:1 and added to a grinder. The mixture was ground to a particle size of <5 μm and then vacuum dried at 120 °C for 2 h to obtain a porous MgCl2 carrier.

[0049] (2) Under nitrogen protection, a porous MgCl2 carrier (2.0 g), 3-methyl-5-tert-butyl-1,2-benzenediol benzoate (0.5 g) prepared in Example 1, and toluene (50 mL) were mixed, heated to 80 °C, and TiCl4 (10 mL) was added dropwise. The mixture was stirred at a constant temperature for 4 h, cooled, centrifuged, washed, and dried to obtain the product.

[0050] Comparative Example 1

[0051] Compared with Example 1, the only difference is that sodium ethoxide is not added in step (2).

[0052] The yield of 3-methylcatechol prepared in step (2) is 76.8% and the purity is 80.3%.

[0053] Comparative Example 2

[0054] Compared with Example 1, the only difference is that the sodium ethoxide in step (2) is replaced by sodium bicarbonate.

[0055] The yield of 3-methylcatechol prepared in step (2) is 83.4% and the purity is 89.9%.

[0056] Comparative Example 3

[0057] Compared with Example 1, the only difference is that triisobutylaluminum in step (3) is replaced by aluminum chloride.

[0058] The yield of 5-tert-butyl-3-methylcatechol prepared in step (3) is 84.1% and the purity is 87.6%.

[0059] Comparative Example 4

[0060] Compared with Example 1, the only difference is that the eluent in step (4) is petroleum ether:ethyl acetate = 5:1 (v / v).

[0061] The yield of 3-methyl-5-tert-butyl-1,2-benzenediol benzoate prepared in step (4) is 90.4% and the purity is 89.5%.

[0062] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a substituted phenylene aromatic diester, characterized in that: The steps include: (1) 2-Hydroxy-3-methylbenzaldehyde reacts with m-chloroperbenzoic acid and sodium ethoxide to produce 3-methylcatechol; (2) Using triisobutylaluminum as a catalyst, 3-methylcatechol reacts with isobutylene to produce 5-tert-butyl-3-methylcatechol; (3) Finally, 5-tert-butyl-3-methylcatechol is reacted with triethylamine and benzoyl chloride to obtain: After the reaction in step (3) is completed, the liquid is separated, the organic phase is combined, the solvent is distilled off, and the product is purified by column chromatography and dried. The eluent for the column chromatography purification is a mixture of petroleum ether and ethyl acetate in a volume ratio of 7-9:

1.

2. The preparation method according to claim 1, characterized in that The molar ratio of 2-hydroxy-3-methylbenzaldehyde, m-chloroperbenzoic acid and sodium ethoxide in step (1) is 1:1-2:2-4.

3. The preparation method according to claim 1, characterized in that In step (1), the reaction temperature is 20-25° C., the reaction time is 2-3 h, and acetonitrile is used as the reaction solvent.

4. The preparation method according to claim 3, characterized in that In step (1), the progress of the reaction is monitored by TLC, and the developing solvent of TLC is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2-4:

1. After the reaction is completed, post-treatment is also performed, and the post-treatment includes adding a sodium thiosulfate aqueous solution with a volume fraction of 10%-15% to the reaction solution, separating the liquids, combining the organic phases and drying.

5. The preparation method according to claim 1, characterized in that The molar ratio of 3-methylcatechol, isobutylene and triisobutylaluminum in step (2) is 1:2-3:0.05-0.

1.

6. The preparation method according to claim 1, characterized in that In step (2), the reaction atmosphere is nitrogen or argon, the reaction temperature is 20-30 ° C, and the reaction time is 2-4 h. After the reaction is completed, the reaction solution needs to be washed with water to neutrality, separated, and the organic phases are combined, purified by column chromatography, and dried.

7. The preparation method according to claim 1, characterized in that In step (3), the reaction atmosphere is nitrogen or argon, the reaction temperature is 20-30°C, the reaction time is 0.5-1.5 h, and the reaction solvent is dichloromethane.

8. The preparation method according to claim 1, characterized in that The preparation process of 2-hydroxy-3-methylbenzaldehyde in step (1) comprises: condensing o-cresol with paraformaldehyde to generate 2-hydroxy-3-methylbenzaldehyde.

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