Method for preparing resorcinol through micro-channel reaction

Abstract

The present disclosure provides a method for preparing resorcinol through micro-channel reaction. In the method, resorcinol is prepared through micro-channel reaction using m-aminophenol as a raw material, a diazo salt is synthesized at 0° C. or more, hydrolysis of the diazo salt is performed at 90° C. or less, and then reaction conditions are reduced; the reaction time is decreased from traditional 10 hours to less than 2 minutes, and therefore the reaction time is significantly shortened; the purity of a product is 75% or more, which is significantly improved. The method provided by the present disclosure has high heat exchange efficiency and high mass transfer rate; the efficiency of reaction is improved by hundreds of times; the reaction system is precisely controlled in the temperature and pressure, and safe and reliable in process, and meanwhile is capable of stably controlling hazard processes such as diazotization, so as to promote safe industry production, reduce energy consumption and greatly reduce industrial hazard waste emission and realize green ecology development.

Claims

1. A method for preparing resorcinol through micro-channel reaction, comprising the following steps: (1) preparation of a diazo salt: mixing m-aminophenol with sulfuric acid aqueous solution to obtain a first mixture, then conveying the first mixture to a first reaction module in a micro-reactor to be pre-cooled to 5˜15° C., wherein the concentration of the sulfuric acid solution is 20˜35%, and a molar ratio of the m-aminophenol to the sulfuric acid solution is 1:2˜3.5; conveying sodium nitrite aqueous solution to a second reaction module in the micro-reactor to be pre-cooled to 5˜15° C.; conveying the pre-cooled materials obtained in the first reaction module and the second reaction module to a third reaction module in the micro-reactor to be mixed and reacted, wherein the temperature of the third reaction module is 5˜30° C., then conveying the above obtained mixture to a fourth reaction module in the micro-reactor to react to obtain a m-aminophenol diazo salt, wherein the temperature of the fourth reaction module is 5˜30° C.; (2) hydrolysis of the diazo salt: respectively conveying an organic solvent and water to a fifth reaction module in the micro-reactor to be preheated to 60˜90° C., then conveying the above preheated material to a sixth reaction module in the micro-reactor, and meanwhile conveying the m-aminophenol diazo salt obtained in step (1) to the sixth reaction module to be mixed to obtain a hydrolysis reactant, wherein the temperature of the sixth reaction module is 60˜90° C., conveying the hydrolysis reactant to a seventh reaction module for further hydrolysis reaction, wherein the temperature of the hydrolysis reaction is 60˜90° C., finally conveying the above obtained hydrolysis reactant to a cooling module to be cooled, and collecting a product to obtain the resorcinol, wherein the first reaction module is independent from the second reaction module, and the fourth reaction module is independent from the fifth reaction module.

2. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (1), the conveying rate of the first mixture is 0.02˜12 kg/min.

3. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (1), the conveying rate of the sodium nitrite solution is 0.012˜6.79 kg/min.

4. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (1), a molar ratio of sodium nitrite to m-aminophenol is 0.95˜1.2:1.

5. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (1), the reaction temperature of the fourth reaction module is 5˜30° C., and the reaction time is 15˜40 s.

6. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (2), the organic solvent comprises one of ethyl acetate, n-butanol and n-butyl acetate, the conveying rate of the organic solvent is 0.0014˜13.59 kg/min, and the conveying rate of water is 0.003˜3.09 kg/min.

7. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (2), a molar ratio of organic solvent to m-aminophenol diazo salt is 6˜9:1.

8. The method for preparing resorcinol through micro-channel reaction according to claim 1, wherein in step (2), the time of hydrolysis reaction is 20˜45 s.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a better understanding of the embodiments of the present disclosure or the technical solution in the prior art, the drawings used in the embodiments or in the prior art will be simply discussed below, obviously, the drawings in the description below are only some Examples in the present disclosure. Persons of ordinary skill in the art can also obtain other drawings according to these drawings without creative efforts.

(2) FIG. 1 is a flowchart of a feed reaction of a method for preparing resorcinol through micro-channel reaction provided by the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

(3) To make the purpose, the features and the benefits of the present disclosure more clear, the technical solution of the present disclosure will be described in detail. Obviously, the described Examples are only some Examples of the present disclosure but not all the Examples. Based on the Examples of the present disclosure, other implementation modes obtained by persons of ordinary skill in the art without creative efforts are all included within the scope of protection of the present disclosure.

(4) The following examples of the present disclosure use Corning G1-10FM reactor (namely AFR®-G1-10FM reactor), four Corning pumps are used to convey materials, two Corning® heat exchangers are used to control the temperature of the reactor, and finally one module is cooled using air.

(5) The present disclosure provides a method for preparing resorcinol through micro-channel reaction, comprising the following steps: (1) preparation of a diazo salt: m-aminophenol with sulfuric acid aqueous solution having a concentration of 20˜35% were mixed to obtain a first mixture, wherein a molar ratio of the m-aminophenol to sulfuric acid solution was 1:2˜3.5, and the obtained first mixture was conveyed via a first feed pump (Feed A) at the conveying rate of 0.02˜12 kg/min to a first reaction module in a G1 reactor to be pre-cooled to 5˜15° C.; sodium nitrite aqueous solution having a concentration of 20˜40% was conveyed via a second feed pump (Feed B) at the conveying rate of 0.006˜3.4 kg/min to a second reaction module in the G1 reactor to be pre-cooled to 5˜15° C.; the pre-cooled materials obtained in the first reaction module and the second reaction module were conveyed to a third reaction module in the micro-reactor to be mixed, wherein a molar ratio of sodium nitrite to m-aminophenol is 0.95˜1.2:1, and the temperature of the third reaction module was 5˜30° C. to react, the above obtained mixture was conveyed to a fourth reaction module in the micro-reactor to react to obtain a m-aminophenol diazo salt, wherein the temperature of the fourth reaction module was 5˜30° C., and the reaction time was 15˜40 s; hydrolysis of the diazo salt: an organic solvent having a purity of 99.8% which was one of ethyl acetate, n-butanol and n-butyl acetate and water were respectively conveyed to a fifth reaction module via a third feed pump (Feed C) at the conveying rate of 0.0014˜13.59 kg/min and via a fourth feed pump (Feed D) at the conveying rate of 0.003˜3.09 kg/min to be preheated to 60˜90° C., then the organic solvent was conveyed via the third feed pump, the water was conveyed via the fourth feed pump, and meanwhile the m-aminophenol diazo salt obtained in step (1) was conveyed to a sixth reaction module to be mixed to obtain a hydrolysis reaction mixture, a molar ratio of the organic solvent to the diazo salt is 6˜9:1, the temperature of the sixth reaction module was 60˜90V, the hydrolysis reaction mixture was conveyed to a seventh reaction module to react and flowed through an eighth reaction module and a ninth reaction module via the seventh reaction module for hydrolysis reaction, the temperatures from the seventh reaction module to the ninth reaction module were all maintained at 60˜90° C., hydrolysis reaction time was 20˜45 s, and then finally the resulting hydrolysis reactant was fed to a cooling module and finally flowed out of the reactor to enter into a collection tank to obtain the resorcinol.

(6) The present disclosure provides the following examples and comparative examples, wherein examples 1˜5 are seen in Table 1, examples 6˜9 and comparative examples 1-2 are seen in Table 2, and examples 10˜13 and comparative examples 3˜4 are seen in Table 3.

(7) TABLE-US-00001 TABLE 1 Parameters of examples 1~5 Groups Example 1 Example 2 Example 3 Example 4 Example 5 Weight (g) of m- 281.2 365.5 281.2 365.5 281.2 aminophenol Concentration (%) of 30 30 30 30 30 sulfuric acid Molar ratio of m-    1:2.5    1:2.5    1:2.5    1:2.5    1:2.5 aminophenol to sulfuric acid Conveying rate 0.02 0.5 6 12 2 (kg/min) of Feed A Pre-cooling 10 10 10 5 15 temperature (° C.) of first reaction module Concentration (%) of 528.5/26.6 635.5/26.6 513.7/26.6 644.87/26.6 528.5/26.6 sodium nitrite weight (g) Conveying rate 0.006 0.5 3.4 1.0 0.06 (kg/min) of Feed B Pre-cooling 10 10 10 5 15 temperature (° C.) of second reaction module Molar ratio of sodium 1.07:1   0.99:1   1.05:1   1.05:1   1.15:1   nitrite to m-aminophenol Temperature (° C.) of 10 5 15 30 15 third reaction module Temperature (° C.) of 10 5 15 30 15 fourth reaction module Reaction time(s) of 34.7 35.8 17.4 34.8 34.7 step (1) Conveying rate 0.016 0.0014 13.59 2 0.15 (kg/min) of Feed C Conveying rate 0.005 0.02 1.05 3.09 2.84 (kg/min) of Feed D Temperature (° C.) of 60 90 80 80 60 fifth reaction module Varity of organic n-butyl Ethyl n-butanol n-butyl n-butyl solvents acetate acetate acetate acetate Molar ratio of organic  7.6:1   6.43:1   7.58:1    7.3:1      9:1   solvent to m-aminophenol Temperature (° C.) of 60 90 80 80 60 sixth reaction module Temperature (° C.) of 60 90 80 80 60 hydrolysis reaction  Hydrolysis time(s) 40.4 43 22.6 40.5 45

(8) Other variables of reactions in examples 6˜9 and comparative examples 1-2 are the completely same, the difference is the concentration of sulfuric acid, wherein the concentrations of sulfuric acids in examples 6˜9 and comparative examples 1-2 are seen in Table 2.

(9) TABLE-US-00002 TABLE 2 Concentrations of sulfuric acids examples 6~9 and comparative examples 1~2 Comparative Comparative Groups Example 1 Example 6 Example 7 Example 8 Example 9 Example 2 Amount of 2.5 eq 2.5 eq 2.5 eq 2.5 eq 2.5 eq 2.5 eq sulfuric acid Concentration 15 20 25 30 35 40 of sulfuric acid

(10) Other variables in reactions in examples 10˜13 and comparative examples 3˜4 are the completely same and the difference is the molar ratio of m-aminophenol to sulfuric acid, specifically see in Table 3.

(11) TABLE-US-00003 TABLE 3 Partial parameters of examples 10~13 and comparative examples 3~4 Comparative Comparative Groups Example 3 Example 10 Example 11 Example 12 Example 13 Example 4 Amount of m- 1.0 eq 1.0 eq 1.0 eq 1.0 eq 1.0 eq 1.0 eq aminophenol Amount of 1.5 eq 2.0 eq 2.5 eq 3.0 eq 3.5 eq 4.0 eq sulfuric acid

(12) Test Example

(13) m-aminophenol (reaction solution) obtained in examples 1˜13 and comparative examples 1˜4 is detected using high performance liquid chromatography. Specific detection conditions are as follows: Flow velocity: 0.8 mL/min Chromatographic column C18 4.6×250 mm (Shimadzu C18 4.6×250 mm Chromatographic column) Detection wavelength: 274 nm Column temperature: 30° C. Flowing phase: A phase: water: B phase: methanol Loading amount: 10 μL

(14) 1. 100 g of resorcinol reaction products (reaction solution) obtained from step (2) in examples 1˜5 were extracted respectively for later use, and then diluted by 5000 folds. Purity detection was performed using Shimadzu high performance liquid chromatograph. Results are seen in Table 4.

(15) TABLE-US-00004 TABLE 4 Purity detection results of resorcinol obtained in examples 1~5 Groups Example 1 Example 2 Example 3 Example 4 Example 5 Purity (%) 82.0 75.0 79.24 78.04 75.14

(16) It can be seen from Table 4 that in the preparation method of the new continuous flow micro-channel process for diazotization and hydrolysis of resorcinol provided by the present disclosure, the preparation time is within two minutes, the purity of the obtained resorcinol is 75% or more, the preparation period is short, the preparation efficiency is high, and the purity of the obtained product is high.

(17) 2. 100 g of resorcinol reaction products (reaction solution) obtained from step (2) in examples 6˜9 and comparative examples 1-2 were respectively taken to detect the purity of the reaction solution, and the purity and yield of the crude product. Results are seen in Table 5.

(18) TABLE-US-00005 TABLE 5 Detection results of examples 6~9 and comparative examples 1~2 Amount Concen- of tration of Purity of Purity Amount Yield sulfuric sulfuric reaction of crude of crude of crude acid acid solution product product product Comparative 2.5 eq 15% 69.2% 81.2% 4.9 g 44.5% example 1 Example 6 2.5 eq 20% 80.1% 97.9% 6.3 g 57.3% Example 7 2.5 eq 25% 81.3% 98.5% 6.4 g 58.2% Example 8 2.5 eq 30% 80.3% 98.4% 6.3 g 57.3% Example 9 2.5 eq 35% 79.7% 99.6% 5.9 g 53.6% Comparative 2.5 eq 40% 58.7% 76.5% 3.6 g 32.7% example 2

(19) It can be seen from results in Table 5 in that in examples 6˜9, the concentration of sulfuric acid is between 20% and 35%, the purity of the obtained reaction solutions is 79.7% or more, the purity of the crude products is 98.4% or more, the yield of the crude products is 53.6% or more; when the concentration of sulfuric acids is 15%, the purity of the obtained reactions solution is 69.2%, the purity of the crude products is 81.2%, the yield of the crude products is 44.5%; when the concentration of sulfuric acid is 40%, the purity of the reaction solution is 58.7%, the yield of the crude product is 76.5%, and the yield of the crude product is 32.7%. Accordingly, when the concentration of sulfuric acid is less than 20% or more than 35%, the purity and yield of the obtained resorcinol are seriously affected.

(20) 3. 100 g of resorcinol reaction products (reaction solution) obtained from step (2) in examples 10˜13 and comparative examples 3˜4 were respectively taken to detect the purity of the reaction solution, and the purity and yield of the crude product. Results are seen in Table 6.

(21) TABLE-US-00006 TABLE 6 Detection results of examples 10~13 and comparative examples 3~4 Amount Concen- Purity Purity Amount Yield of m- tration of of of of amino- of sulfuric reaction crude crude crude phenol acid solution product product product Comparative 1.0 eq 1.5 eq 70.1% 89.2% 5.1 g 46.3% example 3 Example 10 1.0 eq 2.0 eq 75.6% 99.2% 5.5 g 50.0% Example 11 1.0 eq 2.5 eq 78.2% 98.9% 6.4 g 58.2% Example 12 1.0 eq 3.0 eq 80.4% 98.9% 6.5 g 59.1% Example 13 1.0 eq 3.5 eq 80.6% 98.7% 6.4 g 58.2% Comparative 1.0 eq 4.0 eq 65.3% 82.5% 4.2 g 38.1% example 4

(22) It can be seen from results in Table 6 in that when the molar ratio of m-aminophenol to sulfuric acid is between 1:2 and 3.5, the purity of the reaction solution is 75.6% or more, the purity of the crude product is 98.7% or more, the yield of the crude product is 50% or more; when the molar ratio of m-aminophenol to sulfuric acid is less than 1:3.5 or more than 1:2, the purity and yield of the crude product are greatly reduced, which indicates that the m-aminophenol and sulfuric acid provided by the present disclosure within the above ranges can effectively improve the yield and purity of the crude product.

(23) The above descriptions are only embodiments of the present disclosure, however, the protective scope of the present disclosure is not limited to thereto. Any persons of skill in the art can easily conceive that changes or replacements within the technical scope disclosed in the present disclosure should be included within the protective scope of the present, disclosure. Therefore, the protective scope of the present disclosure shall be subject to the protective scope of the claims.