Method for preparing phenylethyl resorcinol through microchannel reaction

Abstract

The invention discloses a method for preparing phenylethyl resorcinol through microchannel reaction, which comprises the following steps: uniformly mixing resorcinol, a solid acid catalyst and a solvent to obtain a mixed solution, respectively pumping the mixed solution and styrene into a microchannel reactor to carry out Friedel-Crafts alkylation reaction, and carrying out post-treatment after the reaction to obtain the phenylethyl resorcinol. The solid superacid catalyst is adopted to catalyze the reaction of resorcinol and styrene, compared with a traditional sulfuric acid catalyst, the catalyst has higher activity and selectivity, the reaction efficiency can be effectively improved, and meanwhile the problems of strong corrosivity and environmental pollution of the sulfuric acid catalyst are solved.

Description

Technical Field

[0001] This invention belongs to the field of phenylethyl resorcinol preparation technology, and in particular relates to a method for preparing phenylethyl resorcinol by microchannel reaction. Background Technology

[0002] In the fields of organic and polymer chemistry, phenylethyl resorcinol is an important chemical raw material, widely used in pharmaceuticals, cosmetics, plastics, and other industries. Traditional methods for preparing phenylethyl resorcinol mainly involve the Friedel-Crafts alkylation reaction of resorcinol with styrene under high temperature and pressure. However, this method suffers from harsh reaction conditions, high energy consumption, and low product yield and purity. Microreactor technology is an emerging chemical technology in recent years. Its main characteristics are a complex internal reactor structure and diverse fluid flow patterns, enabling efficient mixing and rapid reactions of materials. Conducting chemical reactions in microreactors can significantly improve reaction efficiency, reduce energy consumption, and increase product yield and purity. Existing technological solutions: To address the problems in traditional phenylethyl resorcinol preparation methods, researchers have begun exploring the use of microreactor technology for its preparation. For example, some researchers have used sulfuric acid as a catalyst to carry out the alkylation reaction of resorcinol with styrene in a microreactor, achieving some success. However, the sulfuric acid catalyst used in this method is highly corrosive, requires sophisticated equipment, and is prone to environmental pollution. Secondly, existing catalysts often suffer from low activity, poor selectivity, and easy deactivation, affecting reaction efficiency and product quality. Furthermore, the reaction process may generate high pressure and high temperature, posing safety hazards.

[0003] Therefore, selecting appropriate process conditions is of great significance for preparing high-purity, high-yield phenylethyl resorcinol. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing phenylethyl resorcinol via microchannel reaction. By selecting the appropriate catalyst and combining process steps and conditions, the reaction can be carried out under milder conditions without the need for high temperature and high pressure, thus improving the safety of the reaction, the yield of the product, and its purity.

[0005] The specific technical solution of this invention is as follows: A method for preparing phenylethyl resorcinol via microchannel reaction includes the following steps: mixing resorcinol, a solid acid catalyst, and a solvent to obtain a mixture; pumping the mixture and styrene into a microchannel reactor for Friedel-Crafts alkylation reaction; and performing post-processing after the reaction to obtain phenylethyl resorcinol.

[0006] Furthermore, the catalyst is SO4. 2- / TiO2、SO4 2- One of ZrO2-SiO2 and N-methylpyrrolidone hydrogen sulfate ([Hnmp]HSO4), preferably SO4. 2- / ZrO2-SiO2. All catalysts are commercially available.

[0007] Furthermore, the amount of catalyst used is 0.2 to 1% of the mass of styrene, for example 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, preferably 0.4 to 0.8%.

[0008] Furthermore, the solvent is one or more selected from diethyl ether, n-hexane, toluene, benzene, ethanol, and acetone, preferably a mixture of n-hexane and acetone. When the solvent is a mixture of n-hexane and acetone, it has the advantages of enhanced solubility, more uniform material mixing, and more thorough reaction. The molar ratio of n-hexane to acetone is preferably 4 to 6:1, for example, 4:1, 5:1, or 6:1.

[0009] Furthermore, the molar ratio of the solvent to styrene is 0.5 to 3:1, for example 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, preferably 1 to 2:1.

[0010] Furthermore, the molar ratio of resorcinol to styrene in the mixture is 0.5 to 2:1, for example, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 2:1, preferably 0.8 to 1.2:1.

[0011] Furthermore, in the microchannel reactor, the molar ratio of the raw materials is controlled by controlling the flow rate of the materials. Simultaneously, the selection of the flow rate enhances mass and heat transfer efficiency, ensures flow stability, and optimizes the reaction. The styrene enters the microchannel reactor at a rate of 10-15 g / min, and the rate at which the mixed liquid enters the microchannel reactor ensures that the resorcinol in the mixed liquid enters the microchannel reactor at a rate of 8-20 g / min.

[0012] Furthermore, in the microchannel reactor, the reaction temperature is 45–55°C, and the residence time of the material in the microchannel reactor is 10–15 min.

[0013] Furthermore, the microchannel reactor used in this invention can be of various commercially available types, such as parallel multichannel microchannel reactors.

[0014] Further, after the reaction is complete, the reaction solution is filtered, and the filtrate is evaporated and concentrated to obtain a crude product. The crude product is dissolved in a solvent, cooled, and crystallized. The obtained crystals are dried to obtain phenylethyl resorcinol. The evaporation and concentration temperature is 60-70℃, and the product is concentrated until no liquid flows out, and then concentrated for another 0.5-1 hour to obtain the crude product. The solvent used to dissolve the crude product is the same as the solvent used in the reaction. After the crude product is added to the solvent, it is heated and stirred until dissolved. The heating temperature is 70-80℃, and the stirring speed is 150-300 rpm. After the crude product is completely dissolved, it is cooled to -10-0℃ at a rate of 0.5℃ / min to 1℃ / min to crystallize, obtaining a solid-liquid mixture. The solid-liquid mixture is separated, and the obtained solid is dried at 55-60℃ to constant weight to obtain the phenylethyl resorcinol product.

[0015] Compared with existing technologies, the present invention has the following advantages: 1. This invention uses a solid superacid catalyst to catalyze the reaction between resorcinol and styrene. Compared with traditional sulfuric acid catalysts, this catalyst has higher activity and selectivity, which can effectively improve the reaction efficiency, while also avoiding the strong corrosiveness and environmental pollution problems of sulfuric acid catalysts.

[0016] 2. The present invention prepares phenylethyl resorcinol in a microchannel reactor. Compared with the traditional batch reactor, the microchannel reactor has a complex internal structure and diverse fluid flow patterns, and has high-efficiency heat and mass transfer performance. It can realize efficient mixing and rapid reaction of materials, thereby greatly improving reaction efficiency, reducing energy consumption, and improving product yield and purity.

[0017] 3. By adjusting the material flow rate, a stable laminar or weakly turbulent state is maintained in the channel. The fluid shear force is used to flush the inner wall of the channel and the surface of the catalyst, ensuring continuous material flow and reducing material adsorption and deposition. At the same time, the catalyst improves the reaction efficiency and optimizes the material residence time, avoiding material stagnation and accumulation due to excessively slow reaction rates.

[0018] 4. By selecting solvents, especially mixed solvents, this invention reduces the mass transfer resistance of materials, enabling the reaction to proceed efficiently at normal pressure and low temperature. This replaces the traditional method of relying on high temperature and high pressure to increase solubility, making the process safer.

[0019] 5. The small size effect of the microchannel inner diameter increases the heat transfer coefficient to 10-100 times that of traditional reactors, and the exothermic reaction can be instantly discharged, avoiding side reactions caused by local overheating. 6. The method of the present invention yields products with high yield and purity, and has low production costs, making it suitable for industrial applications. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, making the advantages of the present invention more apparent. It should be understood that the content therein is for illustrative purposes only and is not intended to limit the scope of protection of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0021] In the following embodiments, the SO4 used 2- / ZrO2-SiO2 catalyst, SO4 2- The TiO2 catalyst and N-methylpyrrolidone hydrogen sulfate catalyst were purchased commercially.

[0022] In the following examples and comparative examples, the product yield is calculated using the following formula: Yield = Product quality / (Molar amount of styrene) (molecular weight of phenylethyl resorcinol) 100.

[0023] Example 1 1. First, mix 140g of resorcinol and 140.9g of solvent (hexane:acetone molar ratio = 5:1), then add 0.72g of SO4. 2- The ZrO2-SiO2 catalyst was mixed evenly to obtain a mixed solution.

[0024] 2. The molar ratio of raw materials is controlled by controlling the flow rate of the materials. 120.4 g of styrene is pumped into the microchannel reactor at a rate of 12 g / min using a metering pump. At the same time, the mixed liquid is pumped into the microchannel reactor to ensure that resorcinol enters the microchannel reactor at a rate of 14 g / min. The materials undergo Friedel-Crafts alkylation reaction in the microchannel reactor. The reaction temperature is controlled at 50℃ and the residence time is 11 min to obtain the phenethyl resorcinol synthesis solution.

[0025] 3. The synthesis solution was filtered, and the filtrate was concentrated at 65°C until no liquid flowed out. Concentration was continued for 30 minutes to obtain the crude product. The crude product was added to 100g of a mixed solvent (hexane:acetone molar ratio = 5:1) at 75°C and stirred at 200rpm until the solid was completely dissolved. The resulting solution was then cooled to -5°C at a rate of 0.8°C / min. After observing crystal precipitation, crystallization was continued for 1.5h until no crystals precipitated. The solution was then filtered under pressure. The resulting solid was dried at 55°C to constant weight to obtain phenylethyl resorcinol. The purity (HPLC) of the obtained phenylethyl resorcinol was 99.8%, the yield (based on styrene) was 97.4%, and the appearance was white crystals.

[0026] Example 2 1. Mix 137g of resorcinol and 100.6g of solvent (hexane:acetone molar ratio = 4:1), then add 0.52g of SO4. 2- The ZrO2-SiO2 catalyst was mixed evenly to obtain a mixed solution.

[0027] 2. The molar ratio of raw materials is controlled by controlling the flow rate of the materials. 130g of styrene is pumped into the microchannel reactor at a rate of 10g / min using a metering pump. At the same time, the mixed liquid is pumped into the microchannel reactor to ensure that resorcinol enters the microchannel reactor at a rate of 10.6g / min. The materials undergo Friedel-Crafts alkylation reaction in the microchannel reactor. The reaction temperature is controlled at 45℃ and the residence time is 13min to obtain the phenethyl resorcinol synthesis solution.

[0028] 3. The synthesis solution was filtered, and the filtrate was concentrated at 60°C until no liquid flowed out. Concentration was continued for 50 minutes to obtain a crude product. The crude product was added to 100g of a mixed solvent (hexane:acetone molar ratio = 4:1) at 70°C and stirred at 200rpm until the solid was completely dissolved. The resulting solution was then cooled to -5°C at a rate of 0.5°C / min. After observing crystal precipitation, crystallization continued for 2 hours until no crystals precipitated. The solution was then filtered under pressure. The resulting solid was dried at 60°C to constant weight to obtain phenylethyl resorcinol. The purity (HPLC) of the obtained phenylethyl resorcinol was 98.3%, the yield (based on styrene) was 85.2%, and the appearance was white crystals.

[0029] Example 3 1. First, mix 150g of resorcinol and 186.5g of solvent (hexane:acetone molar ratio = 6:1), then add 0.95g of SO4. 2- The ZrO2-SiO2 catalyst was mixed evenly to obtain a mixed solution.

[0030] 2. The molar ratio of raw materials is controlled by controlling the flow rate of the materials. 118.2g of styrene is pumped into the microchannel reactor at a rate of 15g / min using a metering pump. At the same time, the mixed liquid is pumped into the microchannel reactor to ensure that resorcinol enters the microchannel reactor at a rate of 19g / min. The materials undergo Friedel-Crafts alkylation reaction in the microchannel reactor. The reaction temperature is controlled at 55℃ and the residence time is 15min to obtain the phenethyl resorcinol synthesis solution.

[0031] 3. The synthesis solution was filtered, and the filtrate was concentrated at 70°C until no liquid flowed out. Concentration was continued for 30 minutes to obtain a crude product. The crude product was added to 100g of a mixed solvent (hexane:acetone molar ratio = 6:1) at 70°C and stirred at 200rpm until the solid was completely dissolved. The resulting solution was then cooled to -10°C at a rate of 1°C / min. After observing crystal precipitation, crystallization continued for 1 hour until no crystals precipitated. The solution was then filtered under pressure. The resulting solid was dried at 55°C to constant weight to obtain phenylethyl resorcinol. The purity (HPLC) of the obtained phenylethyl resorcinol was 98.0%, the yield (based on styrene) was 87.9%, and the appearance was white crystals.

[0032] Example 4 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the mixed solvent was replaced with an equimolar amount of n-hexane; and in step 3, the mixed solvent was replaced with an equimolar amount of n-hexane. The purity (HPLC) of the obtained phenylethyl resorcinol was 99.5%, and the yield based on styrene was 93.6%.

[0033] Example 5 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the mixed solvent was replaced with an equimolar amount of acetone; and in step 3, the mixed solvent was replaced with an equal mass of acetone. The purity (HPLC) of the obtained phenylethyl resorcinol was 98.6%, and the yield based on styrene was 90.7%.

[0034] Example 6 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the catalyst was replaced with an equal mass of solid superacid SO4. 2- / TiO2 was used to obtain phenylethyl resorcinol with a purity (HPLC) of 99.0% and a yield of 92.3% based on styrene.

[0035] Example 7 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the catalyst was replaced with an equal mass of N-methylpyrrolidone hydrogen sulfate, and the purity (HPLC) of phenylethyl resorcinol was 98.8%, and the yield was 88.5% based on styrene.

[0036] Example 8 Phenethyl resorcinol was synthesized according to the method in Example 1, except that the residence time in the microchannel reactor was replaced with 15 min, and the purity (HPLC) of phenylethyl resorcinol was 97.9% and the yield was 89.3% based on styrene.

[0037] Example 9 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the mixed solvent was replaced with an equimolar amount of toluene; and in step 3, the mixed solvent was replaced with an equimass amount of toluene. The purity (HPLC) of the obtained phenylethyl resorcinol was 97.5%, and the yield based on styrene was 87.4%.

[0038] Example 10 Phenethyl resorcinol was synthesized according to the method of Example 1, except that in step 1, the mixed solvent was replaced with an equimolar amount of diethyl ether; and in step 3, the mixed solvent was replaced with an equal mass of diethyl ether. The purity (HPLC) of the obtained phenylethyl resorcinol was 96.8%, and the yield based on styrene was 83.2%.

[0039] Comparative Example 1 Phenethyl resorcinol was synthesized according to the method in Example 5, except that the catalyst was replaced with sulfuric acid, and the purity (HPLC) of phenylethyl resorcinol was 97.1% and the yield was 84.6% based on styrene.

[0040] Comparative Example 2 Add 140g of resorcinol and 140.9g of solvent (hexane:acetone molar ratio = 5:1) to a three-necked flask, then add 0.72g of... The SO42- / ZrO2-SiO2 catalyst was mixed evenly, and 120.4 g of styrene was added dropwise. The temperature was controlled at 50℃ and the dropping rate was 0.15 kg / min. After the addition was complete, the reaction was carried out at 75℃ for 6 h. The resulting synthesis solution was filtered, and the filtrate was concentrated at 60℃ until no liquid flowed out. The concentration was continued for 30 min to obtain a crude product. The crude product was added to 100 g of mixed solvent (hexane:acetone molar ratio = 5:1) and completely dissolved at 75℃. Then, the mixture was mechanically stirred at 200 rpm and cooled to -5℃. After observing the precipitation of crystals, the crystallization was continued for 1.5 h until the crystals were completely precipitated. The product was then filtered under pressure, and the resulting solid was vacuum dried at 55℃ to obtain phenylethyl resorcinol. The purity of the obtained phenylethyl resorcinol (HPLC) was 98.9%, and the yield based on styrene was 92.5%.

[0041] Comparative Example 3 1. First, mix 140g of resorcinol and 140.9g of solvent (hexane:acetone molar ratio = 5:1), then add 0.72g of SO4. 2- The ZrO2-SiO2 catalyst was mixed evenly to obtain a mixed solution.

[0042] 2. The molar ratio of raw materials is controlled by controlling the flow rate of the materials. 120.4 g of styrene is pumped into the microchannel reactor at a rate of 24 g / min using a metering pump. At the same time, the mixed liquid is pumped into the microchannel reactor to ensure that resorcinol enters the microchannel reactor at a rate of 28 g / min. The materials undergo Friedel-Crafts alkylation reaction in the microchannel reactor. The reaction temperature is controlled at 50℃ and the residence time is 10 min to obtain the phenethyl resorcinol synthesis solution.

[0043] 3. The synthesis solution was filtered, and the filtrate was concentrated at 65°C until no liquid flowed out. The concentration was then continued for 30 minutes to obtain a crude product. This crude product was added to 100g of a mixed solvent (hexane:acetone molar ratio = 5:1) at 75°C and stirred at 200rpm until the solid was completely dissolved. The resulting solution was then cooled to -5°C at a rate of 0.8°C / min. After observing crystal precipitation, crystallization was continued for 1.5 hours until no crystals precipitated. The solution was then filtered under pressure. The resulting solid was dried at 55°C to constant weight to obtain phenylethyl resorcinol. The purity (HPLC) of the obtained phenylethyl resorcinol was 96.3%, and the yield (based on styrene) was 87.5%. The product appeared as white crystals.

[0044] Comparative Example 4 1. First, mix 140g of resorcinol and 140.9g of solvent (hexane:acetone molar ratio = 5:1), then add 0.72g of SO4. 2- The ZrO2-SiO2 catalyst was mixed evenly to obtain a mixed solution.

[0045] 2. The molar ratio of raw materials is controlled by controlling the flow rate of the materials. 120.4 g of styrene is pumped into the microchannel reactor at a rate of 6 g / min using a metering pump. At the same time, the mixed solution is pumped into the microchannel reactor using a metering pump to ensure that resorcinol enters the microchannel reactor at a rate of 7 g / min. The materials undergo Friedel-Crafts alkylation reaction in the microchannel reactor. The reaction temperature is controlled at 50℃ and the residence time is 21 min to obtain the phenethyl resorcinol synthesis solution.

[0046] 3. The synthesis solution was filtered, and the filtrate was concentrated at 65°C until no liquid flowed out. The concentration was then continued for 30 minutes to obtain a crude product. This crude product was added to 100g of a mixed solvent (hexane:acetone molar ratio = 5:1) at 75°C and stirred at 200rpm until the solid was completely dissolved. The resulting solution was then cooled to -5°C at a rate of 0.8°C / min. After observing crystal precipitation, crystallization continued for 1.5 hours until no crystals precipitated. The solution was then filtered under pressure, and the resulting solid was dried at 55°C to constant weight to obtain phenylethyl resorcinol. The purity (HPLC) of the obtained phenylethyl resorcinol was 95.9%, and the yield (based on styrene) was 85.7%. The product appeared as white crystals. After 5 hours of continuous operation, particles were found to have deposited inside the microchannel reactor.

[0047] The present invention has been described in detail above to explain some of its features. Its purpose is to enable those skilled in the art to understand and implement the content of the present invention. However, it should not be construed as limiting the scope of protection of the present invention. Moreover, the present invention is not limited to the above-described embodiments. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing phenylethyl resorcinol via microchannel reaction, characterized in that: Includes the following steps: Resorcinol, a solid acid catalyst, and a solvent were mixed evenly to obtain a mixture. The mixture and styrene were then pumped separately into a microchannel reactor for Friedel-Crafts alkylation. After the reaction, post-treatment was performed to obtain phenethyl resorcinol.

2. The method according to claim 1, characterized in that: The catalyst is SO4. 2- / TiO2、SO4 2- One of ZrO2-SiO2 and N-methylpyrrolidone hydrogen sulfate, preferably SO4. 2- / ZrO2-SiO2.

3. The method according to claim 1 or 2, characterized in that: The catalyst is 0.2-1% of the mass of styrene, preferably 0.4-0.8%.

4. The method according to claim 1, characterized in that: The molar ratio of resorcinol to styrene is 0.5 to 2:1, preferably 0.8 to 1.2:

1.

5. The method according to claim 1, characterized in that: The solvent is at least one selected from diethyl ether, n-hexane, toluene, benzene, ethanol, and acetone, preferably a mixture of n-hexane and acetone; preferably, the molar ratio of the solvent to styrene is 0.5 to 3:1, more preferably 1 to 2:

1.

6. The method according to claim 1, characterized in that: The styrene inlet rate is 10-15 g / min, and the inlet rate of hydroquinone in the mixture is 8-20 g / min.

7. The method according to claim 1, characterized in that: in In the microchannel reactor, the reaction temperature is 45–55℃, and the residence time of the material in the microchannel reactor is 10–15 min.

8. The method according to claim 1, characterized in that: after the reaction, the reaction solution is filtered, the filtrate is concentrated to obtain a crude product, the crude product is dissolved in a solvent and cooled to crystallize, and the obtained crystals are dried to obtain phenylethyl resorcinol.

9. The method according to claim 8, characterized in that: The filtrate was evaporated and concentrated at 60-70℃ until no liquid flowed out. The concentration was continued for 0.5-1h to obtain the crude product. The crude product was added to a solvent and heated to 70-80℃ to dissolve it. Then, the temperature was lowered to -10-0℃ at a rate of 0.5-1℃ / min to crystallize.