CN112390720B - Method for synthesizing 1, 5-dinitroanthraquinone by continuous flow microchannel reactor - Google Patents
Method for synthesizing 1, 5-dinitroanthraquinone by continuous flow microchannel reactor Download PDFInfo
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- CN112390720B CN112390720B CN202011359096.2A CN202011359096A CN112390720B CN 112390720 B CN112390720 B CN 112390720B CN 202011359096 A CN202011359096 A CN 202011359096A CN 112390720 B CN112390720 B CN 112390720B
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- C07C201/06—Preparation of nitro compounds
- C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
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Abstract
The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing 1, 5-dinitroanthraquinone by using a continuous flow microchannel reactor. In particular to a process method for generating 1, 5-dinitro by continuously nitrifying anthraquinone serving as a substrate in a continuous flow microchannel reactor.
Description
Technical Field
The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing 1, 5-dinitroanthraquinone by using a continuous flow microchannel reactor.
Background
1. 5-dinitroanthraquinone is one of the most important anthraquinone derivatives, is an important intermediate for synthesizing anthraquinone dyes, has wide application and high consumption, and can be used for producing disperse, reduction, acid and active dyes, inks, coatings, polymer pigments and other applications. Although there are many ways to produce 1, 5-dinitroanthraquinone, the most competitive method currently exists for the nitration of anthraquinones to produce 1, 5-dinitroanthraquinone.
The nitration of anthraquinone is mainly carried out by three methods, namely a pure nitric acid nitration method, a mixed acid nitration method and a solvent nitration method. In the pure nitric acid nitration method, the molar ratio of anthraquinone to nitric acid is about 1:19, the purity is not high, and the yield is 73%. The yield of the mixed acid nitration method is 75%, the reaction system is close to paste, the fluidity and the mixing property are poor, and the reaction time is long. The pure nitric acid nitration method and the mixed acid nitration method are almost eliminated due to large acid consumption, low yield and serious wastewater. The solvent method is the most widely used method in the current industrial production, the yield is about 75-83%, and meanwhile, some byproducts and impurities can be obtained and can be further applied after refining. Meanwhile, in an intermittent reaction kettle, nitration reaction inevitably causes local overheating to cause danger due to local uneven mixing, and the method has the advantages of long reaction time, unstable reaction process, high explosion risk and large production risk.
The invention provides a method for synthesizing 1, 5-dinitroanthraquinone by using a continuous flow microchannel reactor, which is a future production trend and has the advantages of high conversion rate, stable performance, safety, reliability, reduction of manpower and convenience for realizing intelligent production.
Disclosure of Invention
The invention aims to provide a process method for preparing 1, 5-dinitroanthraquinone by anthraquinone nitration in a high-flux microchannel reactor. Compared with the prior art, the method can improve the yield and the product purity of the reaction, greatly shorten the reaction period, reduce the use of solvents and the generation of wastes, reduce potential safety hazards and realize continuous intelligent production.
The invention relates to a method for synthesizing 1, 5-dinitroanthraquinone by a continuous flow microchannel reactor, which comprises the following steps:
step 1, preheating an anthraquinone-concentrated sulfuric acid saturated solution, a mixed acid nitrating agent and an organic solvent respectively serving as three strands of materials, and then respectively introducing the materials into a continuous flow microchannel reactor through a metering pump;
step 2, controlling the flow of the materials by a metering pump, enabling the preheated anthraquinone-concentrated sulfuric acid saturated solution, the mixed acid nitration solution of mercury sulfate and the organic solvent to synchronously enter a micro-channel reactor module for mixing reaction according to set flow rates, controlling the reaction temperature by an external heat exchanger, enabling a heat exchange medium to be heat conduction oil, enabling a product to flow out of an outlet of the reactor, and enabling the product to enter a product collecting region for further treatment;
step 3, diluting the material obtained at the outlet of the microchannel reactor by ice water, standing and settling, and separating out sulfuric acid mother liquor; distilling and recovering an organic phase;
wherein the mass ratio of anthraquinone to concentrated sulfuric acid in the anthraquinone-concentrated sulfuric acid saturated solution in the step 1 is 1: 2-6, wherein the mass ratio of the concentrated nitric acid to the concentrated sulfuric acid in the mixed acid nitration solution of the mercury sulfate is 1: 1-5; wherein the concentration of the nitric acid is 85-98 percent, and the concentration of the sulfuric acid is 90-98 percent; the mass of the mercuric sulfate and the anthraquinone is 0,03-0, 05: 1.
wherein the set flow rate of the anthraquinone-concentrated sulfuric acid saturated solution in the step 2 is 10-40ml/min, and the mixed acid nitration solution of mercuric sulfate is 10-20 ml/min; the flow rate of the organic solvent is 5-40 ml/min;
wherein the time for carrying out the mixing reaction in the microchannel reactor module in the step 2 is 40-300 s; the reaction temperature is 100-120 ℃; the reaction pressure is 0-10 bar.
In the above method for preparing 1, 5-dinitroanthraquinone, the organic solvent in steps 1 and 2 is selected from one or more of dichloroethane, chloroform, ethyl acetate, acetone, acetonitrile, cyclohexane, N-dimethylformamide and N, N-dimethylacetamide; wherein the volume ratio of the organic solvent to the anthraquinone is 1-10: 1.
Further, in the method for preparing 1, 5-di-nitroanthraquinone, the mass ratio of anthraquinone to concentrated sulfuric acid in the anthraquinone-concentrated sulfuric acid saturated solution in the step 1 is 1: 3-5; the mass ratio of the concentrated nitric acid to the concentrated sulfuric acid in the mixed acid nitration solution of the mercury sulfate is 1: 2-4; the flow rate of the anthraquinone-concentrated sulfuric acid saturated solution in the step 2 is set to be 10-20 ml/min; the flow rate of the mixed acid nitration solution of the mercury sulfate is 10-14 ml/min; the flow rate of the organic solvent is 10-20 ml/min; the time for carrying out the mixing reaction in the microchannel reactor module in the step 2 is 60-150 s; the reaction temperature is 100 ℃; the reaction pressure is 0-5 bar.
The above reactions are all carried out in a continuous flow microchannel reactor with a certain structure, and the reaction system comprises a metering device, a reaction device, a product collecting and processing device and other different functional device areas.
The microchannel reactor module is divided into a direct-current channel structure and an enhanced mass transfer structure, wherein the direct-current channel structure is in a tubular structure and the like, and the enhanced mass transfer structure is in a heart shape or other shapes and the like.
The invention has the beneficial effects that:
the process is carried out in a continuous flow microchannel reactor, the reaction time is only dozens of seconds to several minutes, the reaction time is greatly reduced, the generation of side reactions is reduced, and the production efficiency is greatly improved.
The adopted equipment has accurate temperature control, rapid reaction, excellent heat transfer performance, temperature runaway prevention, and higher safety and reliability.
The adopted equipment is made of special glass, ceramics, silicon carbide and the like, and has stable performance and long service life. The continuous production quality is stable, manual operation is reduced, and intelligent production is convenient to realize. Can realize that one production line produces a plurality of nitroanthraquinone derivatives, and saves the configuration of production equipment for enterprises.
Drawings
FIG. 1 is a structural unit diagram of a microchannel reactor used in the present invention, wherein a is a straight flow channel with a tubular structure, and b is an enhanced mass transfer channel with a heart-shaped structure.
FIG. 2 is a simplified flow chart of the present invention.
FIG. 3 is a diagram of a simple apparatus of the present invention, in which 1, 2, 3, 4, 5 are raw material tanks, 6, 7, 8, 9, 10 are raw material weighing devices, 11, 12, 13 are mixing and preheating devices, 14, 15, 16 are metering pumps, 17, 18, 19 are pressure gauges, 20 is a reaction device, and 21 is a product collecting region.
Detailed Description
The present invention will be specifically illustrated below with reference to examples, but is not limited thereto.
Example 1
(1) The connection mode is determined by referring to fig. 2, the channel structure of the reactor is a in fig. 1, the molar ratio is determined according to the volume of the channel and the set flow rate, and the heat exchange medium of the heat exchanger is heat conduction oil.
(2) Mixing 150g of anthraquinone and 900g of sulfuric acid, and stirring to form an anthraquinone-sulfuric acid saturated solution; 92.5g of nitric acid, 370g of sulfuric acid and 4.5g of mercuric sulfate are prepared into a mixed acid nitration solution of mercuric sulfate, and the solvent is dichloroethane. Preheating the three systems, and pumping into a metering pump respectively, wherein the anthraquinone-sulfuric acid saturated solution is pumped into a microchannel reactor at a flow rate of 14ml/min, the mixed acid nitration solution of mercury sulfate is pumped into the microchannel reactor at a flow rate of 10ml/min, and dichloroethane is pumped into the microchannel reactor at a flow rate of 15ml/min, wherein the molar ratio of anthraquinone to nitric acid is 1: 2.1, controlling the reaction temperature at 120 ℃, keeping the reaction temperature for 40s, diluting the product with ice water, settling and absorbing acid, distilling out an organic phase, washing to obtain a crude product of the 1, 5-di-nitroanthraquinone, and detecting by liquid chromatography, wherein the conversion rate of the anthraquinone is 99.5 percent, and the HPLC purity of the 1, 5-di-nitroanthraquinone is 99.3 percent.
Example 2
And (3) determining a connection mode by referring to FIG. 2, wherein the channel structure of the reactor is b in FIG. 1, the molar ratio is determined according to the volume of the channel and the set flow rate, and the heat exchange medium of the heat exchanger is heat conduction oil.
Mixing 150g of anthraquinone and 600g of sulfuric acid, and stirring to form an anthraquinone-sulfuric acid saturated solution; 92.5g of nitric acid, 370g of sulfuric acid and 7.5g of mercuric sulfate are prepared into a mixed acid nitration solution of mercuric sulfate, and the solvent is dichloroethane. Preheating the three systems, and pumping into a metering pump respectively, wherein the anthraquinone-sulfuric acid saturated solution is pumped into a microchannel reactor at a flow rate of 14ml/min, the mixed acid nitration solution of mercury sulfate is pumped into the microchannel reactor at a flow rate of 14ml/min, and dichloroethane is pumped into the microchannel reactor at a flow rate of 15ml/min, wherein the molar ratio of anthraquinone to nitric acid is 1: 2.1, controlling the reaction temperature at 110 ℃, keeping the reaction temperature for 200s, diluting the product with ice water, settling and absorbing acid, distilling out an organic phase, washing to obtain a crude product of the 1, 5-di-nitroanthraquinone, and detecting by liquid chromatography, wherein the conversion rate of the anthraquinone is 99.6 percent, and the HPLC purity of the 1, 5-di-nitroanthraquinone is 99.1 percent.
Example 3
The connection mode is determined by referring to fig. 2, the channel structure of the reactor is a in fig. 1, the molar ratio is determined according to the volume of the channel and the set flow rate, and the heat exchange medium of the heat exchanger is heat conduction oil.
Mixing 150g of anthraquinone and 600g of sulfuric acid, and stirring to form an anthraquinone-sulfuric acid saturated solution; 92.5g of nitric acid, 277.5g of sulfuric acid and 7.5g of mercuric sulfate are prepared into a mixed acid nitration solution of mercuric sulfate, and the solvent is dichloroethane. Preheating the three systems, and pumping into a metering pump respectively, wherein an anthraquinone-sulfuric acid saturated solution is pumped into a microchannel reactor at a flow rate of 14ml/min, a mixed acid nitration solution of mercuric sulfate is pumped into the microchannel reactor at a flow rate of 15ml/min, and dichloroethane is pumped into the microchannel reactor at a flow rate of 15ml/min, wherein the molar ratio of anthraquinone to nitric acid is 1: 2.3, controlling the reaction temperature at 100 ℃, keeping the reaction time at 300s, diluting the product with ice water, settling and absorbing acid, distilling out an organic phase, washing to obtain a crude product of the 1, 5-di-nitroanthraquinone, and detecting by liquid chromatography, wherein the conversion rate of the anthraquinone is 99.8 percent, and the HPLC purity of the 1, 5-di-nitroanthraquinone is 99.1 percent.
Example 4
And (3) determining a connection mode by referring to FIG. 2, wherein the channel structure of the reactor is b in FIG. 1, the molar ratio is determined according to the volume of the channel and the set flow rate, and the heat exchange medium is heat conduction oil.
Mixing 150g of anthraquinone and 600g of sulfuric acid, and stirring to form an anthraquinone-sulfuric acid saturated solution; 92.5g of nitric acid, 185g of sulfuric acid and 5.5g of mercuric sulfate are prepared into a mixed acid nitration solution of mercuric sulfate, and the solvent is chloroform. Preheating the three systems, pumping into a metering pump respectively, pumping an anthraquinone-sulfuric acid saturated solution at 14ml/min, pumping a mixed acid nitration solution of mercuric sulfate into a microchannel reactor at 10ml/min and chloroform at a flow rate of 15ml/min, wherein the molar ratio of anthraquinone to nitric acid is 1: 2.1, controlling the reaction temperature at 110 ℃, keeping the reaction temperature for 60s, diluting the product with ice water, settling and absorbing acid, distilling out an organic phase, washing to obtain a crude product of the 1, 5-di-nitroanthraquinone, and detecting by liquid chromatography, wherein the conversion rate of the anthraquinone is 98.9 percent, and the HPLC purity of the 1, 5-di-nitroanthraquinone is 99.1 percent.
Example 5
The connection mode is determined by referring to fig. 2, the channel structure of the reactor is a in fig. 1, the molar ratio is determined according to the volume of the channel and the set flow rate, and the heat exchange medium of the heat exchanger is heat conduction oil.
Mixing 150g of anthraquinone and 600g of sulfuric acid, and stirring to form an anthraquinone-sulfuric acid saturated solution; 92.5g of nitric acid, 185g of sulfuric acid and 6g of mercuric sulfate are prepared into a mixed acid nitration solution of mercuric sulfate, and the solvent is ethyl acetate. Preheating the three systems, pumping into a metering pump respectively, pumping the anthraquinone-sulfuric acid saturated solution at 14ml/min, pumping the mixed acid nitration solution of mercury sulfate into a microchannel reactor at 15ml/min and the ethyl acetate at the flow rate of 15ml/min, wherein the molar ratio of anthraquinone to nitric acid is 1: 2.3, controlling the reaction temperature at 100 ℃, keeping the reaction time at 100s, diluting the product with ice water, settling and absorbing acid, distilling out an organic phase, washing to obtain a crude product of the 1, 5-di-nitroanthraquinone, and detecting by liquid chromatography, wherein the conversion rate of the anthraquinone is 98.8 percent, and the HPLC purity of the 1, 5-di-nitroanthraquinone is 99.1 percent.
Claims (1)
1. A method for synthesizing 1, 5-dinitroanthraquinone by a continuous flow microchannel reactor is characterized by comprising the following steps:
step 1, preheating an anthraquinone-concentrated sulfuric acid saturated solution, a mixed acid nitration solution of mercuric sulfate and an organic solvent respectively serving as three strands of materials, and then respectively introducing the materials into a continuous flow microchannel reactor through a metering pump;
step 2, controlling the flow of the materials by a metering pump, enabling the preheated anthraquinone-concentrated sulfuric acid saturated solution, the mixed acid nitration solution of mercury sulfate and the organic solvent to synchronously enter a micro-channel reactor module for mixing reaction according to set flow rates, controlling the reaction temperature by an external heat exchanger, enabling a heat exchange medium to be heat conduction oil, enabling a product to flow out of an outlet of the reactor, and enabling the product to enter a product collecting region for further treatment;
step 3, diluting the material obtained at the outlet of the microchannel reactor by ice water, standing and settling, and separating out sulfuric acid mother liquor; distilling and recovering an organic phase;
wherein the mass ratio of anthraquinone to concentrated sulfuric acid in the anthraquinone-concentrated sulfuric acid saturated solution in the step 1 is 1:3-5, and the mass ratio of concentrated nitric acid to concentrated sulfuric acid in the mixed acid nitration solution of mercury sulfate is 1: 2-4; wherein the concentration of the nitric acid is 85-98 percent, and the concentration of the sulfuric acid is 90-98 percent; the mass of the mercuric sulfate and the anthraquinone is 0,03-0, 05: 1; the organic solvent is one or more selected from dichloroethane, chloroform, ethyl acetate, acetone, acetonitrile, cyclohexane, N-dimethylformamide and N, N-dimethylacetamide; the volume ratio of the organic solvent to the anthraquinone is 1-10: 1;
wherein the set flow rate of the anthraquinone-concentrated sulfuric acid saturated solution in the step 2 is 10-20ml/min, and the mixed acid nitration solution of mercuric sulfate is 10-14 ml/min; the flow rate of the organic solvent is 10-20 ml/min;
wherein the time for carrying out the mixing reaction in the microchannel reactor module in the step 2 is 60-150 s; the reaction temperature is 100 ℃; the reaction pressure is 0-5 bar.
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