A method for synthesizing m-tert-butylphenol

Abstract

This invention relates to a method for synthesizing m-tert-butylphenol. In a fixed-bed continuous flow reactor, using Cu / MCM-41 as a catalyst, at a reaction temperature of 240-260℃ and atmospheric pressure, and a feed rate of 5-15 mL / h, a mixture of phenol and di-tert-butyl ether is contacted with a solid catalyst to obtain m-tert-butylphenol. This invention provides a simple, one-step synthesis method for m-tert-butylphenol, yielding high-purity m-tert-butylphenol. The fixed-bed continuous flow reactor is suitable for industrial applications. The reaction equation is as follows:

Description

Technical Field

[0001] This invention belongs to the field of synthesis of fine chemical intermediates, and in particular, a method for synthesizing m-tert-butylphenol. Background Technology

[0002] m-tert-butylphenol, as a phenol derivative, is an important intermediate in fine chemical industry, particularly as a raw material for the synthesis of the fungicide etoxazole and the antioxidant anoxex. However, due to the similar boiling points of m-tert-butylphenol and p-tert-butylphenol, they cannot be separated by distillation. Therefore, the formation of p-tert-butylphenol should be avoided during the synthesis of m-tert-butylphenol, or a catalyst with extremely high selectivity for m-tert-butylphenol should be selected. Only after distillation can high-purity m-tert-butylphenol be obtained.

[0003] CN105198710A discloses a method for synthesizing m-tert-butylphenol, comprising the following steps: using p-tert-butylchlorobenzene as raw material, nitrifying to obtain 1-chloro-4-tert-butyl-2-nitrobenzene, reducing to generate m-tert-butylaniline, diazotizing, and hydrolyzing to obtain m-tert-butylphenol, and distilling along this route to obtain m-tert-butylphenol with a purity of over 97%.

[0004] CN103449975A discloses a method for synthesizing m-tert-butylphenol from p-tert-butyl halobenzene. The method uses p-tert-butyl halobenzene as raw material and obtains m-tert-butylphenol through nitration, reduction, diazotization and hydrolysis.

[0005] CN110903171A discloses a green preparation process for m-tert-butylphenol, using phenol and tert-butyl chloride as raw materials, and acidic clay and concentrated sulfuric acid as catalysts, to obtain the main product m-tert-butylphenol and the byproduct p-tert-butylphenol in one step through an alkylation reaction, which are then separated; using the unreacted phenol and p-tert-butylphenol byproduct as raw materials, and acidic clay and aluminum trichloride as catalysts, m-tert-butylphenol is obtained in one step through a rearrangement reaction.

[0006] The aforementioned patented synthesis process is complex and involves many steps.

[0007] CN110563557A discloses an environmentally friendly synthesis process for m-tert-butylphenol. Using phenol and isobutylene as raw materials, the purified phenol and isobutylene obtained in the above steps are placed in a reaction vessel. Then, a positioning aid, pentasilicic acid, is added to the reaction vessel. Under the action of the pentasilicic acid, phenol and isobutylene are converted into m-tert-butylphenol. This synthesis process is only suitable for small-batch synthesis of m-tert-butylphenol and cannot be applied industrially.

[0008] CN110803981A discloses a method for synthesizing m-tert-butylphenol. The method uses tert-butylbenzene as the raw material. In a four-necked reaction flask equipped with a stirrer, thermometer, and reflux condenser, 12.5 g to 17.8 g of tert-butylbenzene is added, followed by 3.8 g to 5.2 g of copper acetate, then 70 mL to 80 mL of 30% hydrochloric acid solution. Finally, 20 mL of diethyl ether and 2.3 g of polyethylene glycol are added. The temperature is then gradually raised to 110°C to 130°C and reacted at this temperature for 1 hour. The temperature is then raised to 170°C to 190°C and reacted for another 2 hours. After the reaction is complete, the mixture is cooled to room temperature, filtered, and finally distilled under reduced pressure to obtain m-tert-butylphenol. The m-tert-butylphenol synthesized by this patent has a low purity, not exceeding 95%. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for synthesizing m-tert-butylphenol, which can synthesize m-tert-butylphenol in one step, and achieve a purity of over 99% after distillation. The method uses a fixed-bed continuous flow reactor and is suitable for industrial applications.

[0010] The technical solution adopted by this invention to solve the technical problem is:

[0011] This invention provides a method for synthesizing m-tert-butylphenol. In a fixed-bed continuous flow reactor, using Cu / MCM-41 as a catalyst, at a reaction temperature of 240-260℃ and atmospheric pressure, and a feed rate of 5-15 mL / h, a mixture of phenol and di-tert-butyl ether is contacted with a solid catalyst to obtain m-tert-butylphenol. The reaction equation is as follows:

[0012]

[0013] Furthermore, the reaction temperature is preferably 245–255°C, and even more preferably 250°C.

[0014] Furthermore, the feed rate is preferably 9-12 mL / h, and even more preferably 10 mL / h.

[0015] Furthermore, the molar ratio of phenol to di-tert-butyl ether is 2:1 to 1.5, preferably 2:1.1.

[0016] Furthermore, the loading of the active component in the Cu / MCM-41 is 3-8 wt%, preferably 5-7 wt%.

[0017] Furthermore, the Cu / MCM-41 is prepared by an impregnation method. The active component of Cu / MCM-41 is derived from one or more soluble copper salts such as copper nitrate, copper acetate, and copper oxalate. The concentration of the aqueous solution of the soluble copper salt is 0.5–2 mol / L.

[0018] Furthermore, the Cu / MCM-41 requires pre-reduction with hydrogen before the reaction, and the reduction temperature is 210-230℃, preferably 220℃.

[0019] The advantages and positive effects of this invention are:

[0020] The method for synthesizing m-tert-butylphenol in this invention is simple, can be completed in one step, and yields m-tert-butylphenol with high purity. A fixed-bed continuous flow reactor is used, making it suitable for industrial applications. Attached Figure Description

[0021] Figure 1 The image shows the infrared spectrum of m-tert-butylphenol.

[0022] Figure 2 For m-tert-butylphenol 1 H nuclear magnetic resonance spectrum. Detailed Implementation

[0023] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0024] MCM-41 all-silica molecular sieves and ZSM-5 are commercially available, and small-scale preparations can be carried out in the laboratory using existing techniques. Catalysts require reduction and activation before reaction; this is common knowledge among those skilled in the field.

[0025] Example 1

[0026] A method for synthesizing m-tert-butylphenol uses a fixed-bed continuous flow reactor with Cu / MCM-41 catalyst (20 g), a hydrogen pre-reduction temperature of 220°C, a reaction temperature of 250°C, atmospheric pressure, and a mixed solution of phenol and di-tert-butyl ether (molar ratio of 2:1.1) at a feed rate of 10 mL / h.

[0027] The preparation method of Cu / MCM-41 is as follows: using MCM-41 all-silica molecular sieve as a carrier, the Cu loading is 5wt% by impregnation method. Specifically, the mesoporous molecular sieve MCM-41 is added to a copper nitrate aqueous solution with a concentration of 1mol / L, then evaporated to dryness at 60℃, dried at 120℃ for 12h, and then calcined in a muffle furnace at 500℃ for 6h. After pressing and granulation, it is used.

[0028] The preparation method of MCM-41 all-silica molecular sieve is hydrothermal synthesis: 2g of hexadecyltrimethylammonium bromide (template agent) is dissolved in 270mL of distilled water, ammonia water is added to adjust the pH of the solution to 11, and then 10mL of tetraethyl orthosilicate is added. After the solution changes from transparent to milky white, it is transferred to a magnetic stirrer and stirred continuously at 50℃ for 3h. After filtration, it is washed with deionized water and methanol until neutral, dried at 110℃, and calcined at 550℃ for 6h to remove the template agent, thus obtaining MCM-41.

[0029] The phenol conversion rate was 99.8%, the selectivity for m-tert-butylphenol was 98.5%, and the remainder consisted of small amounts of o-tert-butylphenol, p-tert-butylphenol, 2,4-di-tert-butylphenol, and 3,5-di-tert-butylphenol. Distillation yielded m-tert-butylphenol with a purity of 99%.

[0030] Figure 1 The Fourier transform infrared spectrum of m-tert-butylphenol is compared with the standard infrared spectrum. Figure 1 To. Figure 2 The image shows the 1H NMR spectrum of m-tert-butylphenol (using deuterated chloroform as solvent). The chemical shifts and integrated areas of the proton peaks indicate that the obtained product contains no significant impurities. 1 H NMR (400MHz, CDCl3), δ: 7.22(t,1H),7.02(dd,1H),6.92(t,1H),6.70(m,1H),4.94(s,1H),1.34(s,9H).

[0031] Example 2

[0032] The difference from Example 1 is that the Cu loading is 8 wt%, the phenol conversion rate is 98%, the selectivity of m-tert-butylphenol is 97.8%, and m-tert-butylphenol with a purity of 98% is obtained after distillation.

[0033] Example 3

[0034] The difference from Example 1 is that the reaction temperature is 260°C, the phenol conversion rate is 98.5%, the selectivity of m-tert-butylphenol is 95.8%, and m-tert-butylphenol with a purity of 96% is obtained after distillation.

[0035] Comparative Example 1

[0036] By replacing copper nitrate with nickel nitrate, Ni / MCM-41 was prepared with a phenol conversion rate of 85% and a selectivity of 63% for m-tert-butylphenol. After distillation, m-tert-butylphenol with a purity of 68% was obtained.

[0037] Comparative Example 2

[0038] MCM-41 was replaced with ZSM-5 molecular sieve (Si:Al = 50:1, Dalian Institute of Chemical Physics) to prepare Cu / ZSM-5. The phenol conversion rate was 72%, the selectivity of m-tert-butylphenol was 32%, and m-tert-butylphenol with a purity of 43% was obtained after distillation.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A method for synthesizing m-tert-butylphenol, characterized in that, In a fixed-bed continuous flow reactor, using Cu / MCM-41 as a catalyst, a mixture of phenol and di-tert-butyl ether was contacted with a solid catalyst at a reaction temperature of 240-260℃, atmospheric pressure, and a feed rate of 5-15 mL / h to obtain m-tert-butylphenol. The reaction equation is as follows: The Cu / MCM-41 requires pre-reduction with hydrogen before the reaction, and the reduction temperature is 240-260℃.

2. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The molar ratio of phenol to di-tert-butyl ether is 2:1 to 1.

5.

3. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The active component loading in the Cu / MCM-41 is 3-8 wt%.

4. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The Cu / MCM-41 is prepared by impregnation.

5. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The active components of Cu / MCM-41 are derived from one or more of copper nitrate, copper acetate, and copper oxalate.

6. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The reaction temperature is 245–255°C.

7. The method for synthesizing m-tert-butylphenol according to claim 1, characterized in that, The feed rate is 9–12 mL / h.

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