TW202228841A - Preparation method of dinitronaphthalene capable of evenly mixing naphthalene and nitric acid with increased contact probability to obtain dinitronaphthalene - Google Patents

Abstract

The invention relates to a preparation method of dinitronaphthalene, which includes the following steps: performing a nitration reaction of naphthalene and nitric acid placed in a reactor to obtain a solution containing dinitronaphthalene, wherein the reactor comprises a rectangular reaction channel for performing the nitration reaction, and a mixing member disposed in the rectangular reaction channel. The mixing member is provided with several stacked comb-like baffles, and each comb-like baffle has several comb teeth. The comb teeth of the comb-like baffles may be cooperated to make the naphthalene and nitric acid generating irregular flow to be mixed with each other.

Description

The preparation method of dinitronaphthalene

The present invention relates to a kind of nitration method of aromatic compound, especially refers to a kind of preparation method of dinitronaphthalene.

The synthesis method of dinitronaphthalene is mainly synthesized by using nitric acid and naphthalene, or using an acid component containing nitric acid and other acids (such as sulfuric acid or acetic acid) and naphthalene to synthesize, and the method widely used in industry is to use Nitric acid is used as a single nitrating agent to react with naphthalene to prepare dinitronaphthalene.

Chinese Patent Publication No. 104478728 A discloses a method for synthesizing dinitronaphthalene by microchannel reaction. The method takes naphthalene and nitric acid as raw materials, and feeds them into a microchannel reactor for reaction. The microchannel reactor has a microchannel structure. The microchannel structure is, for example, a straight-through tubular channel structure or a heart-shaped channel structure.

Therefore, an object of the present invention is to provide a preparation method of dinitronaphthalene.

Thus, the preparation method of dinitronaphthalene of the present invention comprises the following steps: Naphthalene and nitric acid placed in a reactor are subjected to nitration reaction to obtain a solution containing dinitronaphthalene, wherein the reactor includes a rectangular reaction channel for the nitration reaction to be carried out, and a rectangular reaction channel arranged in the rectangular reaction channel a mixing assembly inside, and the mixing assembly has a plurality of stacked comb-shaped baffles, each comb-shaped baffle has a plurality of comb teeth, and the comb teeth of the comb-shaped baffles cooperate with each other, The naphthalene and nitric acid are mixed with each other so that irregular flow occurs.

Another object of the present invention is to provide a preparation method of dinitronaphthalene.

Therefore, the preparation method of dinitronaphthalene of the present invention comprises the following steps: carrying out nitration reaction of naphthalene and nitric acid placed in a reactor to obtain a solution containing dinitronaphthalene, wherein the reactor comprises several The rectangular reaction channel in which the nitration reaction is carried out, and a plurality of mixing components respectively disposed in the rectangular reaction channels, and each mixing component has a plurality of stacked comb-shaped baffles, and each comb-shaped baffle There are several comb teeth, which are matched through the comb teeth of the comb-shaped guide plates, so that the naphthalene and the nitric acid flow irregularly and are mixed with each other.

The effect of the present invention is: through the flow channels formed by the stacking of the comb-shaped baffles, the irregular flow of naphthalene and nitric acid is generated in the rectangular reaction channels, and the contact probability of naphthalene and nitric acid is increased. was mixed homogeneously to obtain dinitronaphthalene.

The first embodiment of the method for preparing dinitronaphthalene of the present invention comprises the following steps: nitration reaction of naphthalene and nitric acid placed in a reactor to obtain a solution containing dinitronaphthalene, wherein the reactor includes a A rectangular reaction channel for the nitrification reaction, and a mixing assembly arranged in the rectangular reaction channel, and the mixing assembly has several stacked comb-shaped baffles, and each comb-shaped baffle has several combs The teeth are matched through the comb teeth of the comb-shaped baffles, so that the naphthalene and the nitric acid flow irregularly and are mixed with each other; the solution containing dinitronaphthalene is cooled to make the dinitronaphthalene The dinitronaphthalene was precipitated from this solution, and then, a separation treatment was performed to obtain a dinitronaphthalene solid and a residual liquid.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , the reactor includes a shell unit 1 , a shell cover unit 2 , eight reaction tubes 3 , and eight mixing components 4 .

The casing unit 1 includes a first casing wall 11 , a second casing wall 12 spaced from the first casing wall 11 , and a second casing wall 12 located between the first casing wall 11 and the second casing wall 12 and connecting the first casing wall 11 . A casing wall 11 and a surrounding wall 13 of the second casing wall 12 . The first shell wall 11 is formed with eight first through holes 110 arranged at intervals. The second housing wall 12 is formed with eight second through holes 120 corresponding to the corresponding first through holes 110 respectively. The surrounding wall 13 defines a heat-conducting space 130 for the heat medium (not shown) to flow, an inlet 131 communicating with the heat-conducting space 130 and allowing the heat medium to enter, and an inlet 131 communicating with the heat-conducting space 130 and supplying the heat The outlet 132 from which the media flows out.

The case cover unit 2 includes a first case cover 21 covering the first case wall 11 and a second case cover 22 covering the second case wall 12 . The first shell cover 21 has a communication with the first through holes 110 of the first shell wall 11 for supplying the naphthalene from a pipeline (not shown) and the naphthalene from another pipeline (not shown) The injection port 210 into which the nitric acid enters. The second cover 22 has a liquid outlet 220 which communicates with the second through holes 120 of the second shell 12 and is used for the solution containing dinitronaphthalene to flow out.

Referring to FIGS. 2 and 3 , the reaction tubes 3 are connected to the first shell wall 11 and the second shell wall 12 of the shell unit 1 , and are arranged at intervals in the heat conduction space 130 surrounding the wall 13 of the shell unit 1 . Each reaction tube 3 has a rectangular reaction channel 31 communicating with the respective first through holes 110 of the first shell wall 11 and the respective second through holes 120 of the second shell wall 12 . The rectangular reaction channel 31 is used to supply the naphthalene and the nitric acid entering from the injection port 210 of the first shell cover 21 to flow and perform the nitration reaction.

Referring to FIGS. 3 to 5 , the mixing components 4 are respectively disposed in the rectangular reaction channels 31 of the reaction tubes 3 . Each mixing assembly 4 has three comb-shaped deflectors 41 arranged in a stack. Each comb-shaped deflector 41 has a plurality of comb teeth 411 extending toward an extending direction and arranged at intervals, and a connecting piece 412 for connecting the comb teeth 411 together. Each comb tooth 411 and the connecting member 412 form an included angle ranging from 30 degrees to 45 degrees. In the first embodiment, the included angle between each comb tooth 411 and the connecting member 412 is 45 degrees. The distance between two adjacent comb teeth 411 of each comb-shaped deflector 41 is 1 mm to 4 mm. In the first embodiment, the distance between two adjacent comb teeth 411 of each comb-shaped deflector 41 is 2 mm. In each mixing assembly 4 , the comb teeth 411 of the comb-shaped baffles 41 are stacked and the connecting pieces 412 are stacked on the same side, and the comb-shaped baffles 41 of the adjacent two comb-shaped baffles 41 are stacked. The extending directions of the comb teeth 411 from the connecting elements 412 are opposite.

It should be noted that the number of the reaction tubes 3 is not limited to eight, and may be one, two, three, four, nine, ten, etc., and can be adjusted according to requirements. The number of the mixing components 4 is not limited to eight, and is adjusted according to the number of the reaction tubes 3 . The number of comb-shaped baffles 41 of each mixing assembly 4 is not limited to three, and may be two, four, five, etc., and can be adjusted according to requirements. The arrangement of the comb-shaped baffles 41 of each mixing assembly 4 is not limited to the above, for example, the connecting elements 412 of the comb-shaped baffles 41 are arranged on different sides. This reactor is, for example, a commercially available product of the ^Miprowa® series manufactured by Ehrfeld Corporation. In this first embodiment, the reactor is a reactor manufactured by Ehrfeld Company and the model is miprowa lab.

In the present invention, the nitration reaction is carried out at 80°C to 85°C. In this first embodiment, the nitration reaction is carried out at 85°C, and the reaction time is 54 seconds. In the present invention, based on the total amount of the naphthalene and the nitric acid being 100 wt%, the content of the naphthalene ranges from 15 wt% to 20 wt%, and the content of the nitric acid ranges from 80 wt% to 85 wt%. In the first embodiment, the content of the naphthalene is 6 grams, the content of the nitric acid is 24.65 grams, and the total amount of the naphthalene and the nitric acid is 100 wt%, the content of the naphthalene is 19.6 wt%. In the present invention, an aqueous nitric acid solution is used. In this first embodiment, the amount of the nitric acid aqueous solution used is 29 grams, and the concentration of the nitric acid in the nitric acid aqueous solution is 85 wt%.

For example, in the cooling treatment, water is added to the solution containing dinitronaphthalene to cool down or the solution containing dinitronaphthalene is cooled by water. In the present invention, the temperature range of the cooling treatment is 10°C to 20°C. In the present invention, the time range of the cooling treatment is 300 seconds to 600 seconds. In this first embodiment, water is added to the solution containing dinitronaphthalene, and the consumption of this water is 10 times the theoretical yield of dinitronaphthalene, and cooled to 10° C. in 300 seconds. This separation treatment is, for example, filtration treatment or centrifugation treatment. In this first embodiment, the separation process is a filtering process. In this first example, the yield of the dinitronaphthalene solids is 50% to 60%. In the first embodiment, since no organic solvent is used, the residual liquid does not contain an organic solvent, so that the organic solvent recovery process is not required, so that the production cost can be reduced.

A second embodiment of the preparation method of dinitronaphthalene of the present invention is to obtain dinitronaphthalene by a preparation method similar to the first embodiment, the difference is that an organic solvent is placed in the reactor, and the nitration The reaction time of the reaction is 44 seconds, this cooling treatment is to add water in this solution containing dinitronaphthalene, and the consumption of this water is 10 times of the theoretical yield of dinitronaphthalene, and is cooled to 20 ° in 600 seconds C. The organic solvent is selected from dichloromethane, dichloroethane, chloroform, carbon tetrachloride or acetic acid. In this second embodiment, the organic solvent is dichloroethane. Based on the total amount of the naphthalene, the organic solvent and the nitric acid being 100 wt %, the content of the naphthalene ranges from 5 wt % to 10 wt %, and the content of the nitric acid ranges from 63.4 wt % to 68.9 wt %. In this second embodiment, the content of the naphthalene is 4.425 grams, the content of the organic solvent is 13.275 grams, the content of the nitric acid is 30.719 grams, and the total amount of the naphthalene, the organic solvent and the nitric acid is 100 wt %, the naphthalene content was 9.14 wt%, and the nitric acid content was 63.44 wt%. In this second example, the yield of the dinitronaphthalene solid was 86%. From the reaction time of the nitration reaction of the second embodiment and the yield of the dinitronaphthalene solid, it can be seen that the reaction residence time compared to the method of Chinese Patent Publication No. 104478728 A is 50 seconds to 100 seconds and the dinitronaphthalene solid The yield of 85% to 90%, under the equivalent yield of dinitronaphthalene solid, the second embodiment can obtain dinitronaphthalene solid in a shorter reaction time.

In a third embodiment of the preparation method of dinitronaphthalene of the present invention, dinitronaphthalene is obtained by a preparation method similar to that of the second embodiment, except that the cooling treatment in the third embodiment is through The solution containing dinitronaphthalene is cooled to 20 DEG C in 300 seconds by the mode of water cooling, at this moment, the nitric acid concentration in this solution containing dinitronaphthalene is 79.8 wt%, then, in the solution containing dinitronaphthalene Water was added to the solution of naphthalene to dilute the concentration of nitric acid to 71%. In this third example, the yield of the dinitronaphthalene solids was 86%.

In the fourth embodiment of the preparation method of dinitronaphthalene of the present invention, dinitronaphthalene is obtained by a preparation method similar to the third embodiment, the difference is that: in the fourth embodiment, 60 vol% to 70 vol% residual liquid, according to the concentration of nitric acid and dichloroethane in the residual liquid, mix with fresh naphthalene, fresh nitric acid or fresh dichloroethane in an appropriate amount to make up for the needs of each component. The reaction dosage is then introduced into the reactor to carry out the nitration reaction.

To sum up, the preparation method of dinitronaphthalene of the present invention forms several interlaced flow channels in the rectangular reaction channels 31 through the stacking of the comb teeth 411, so that the naphthalene and the nitric acid pass through the The comb-shaped deflector 41 generates irregular flow, so that the naphthalene and the nitric acid can be uniformly mixed under the condition of increasing the contact probability to obtain dinitronaphthalene, so the object of the present invention can be achieved.

However, the above are only examples of the present invention, and should not limit the scope of implementation of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the patent specification are still included in the scope of the present invention. within the scope of the invention patent.

1: Shell element 11: The first shell wall 110: First perforation 12: Second shell wall 120: Second perforation 13: Surrounding the Wall 130: Thermal space 131: Entrance 132:Export 2: Shell cover unit 21: The first shell cover 210: Injection port 22: Second shell cover 220: Liquid outlet 3: reaction tube 31: Rectangular reaction channel 4: Hybrid Components 41: Comb deflector 411: Comb 412: Connector

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: Fig. 1 is a perspective view illustrating a reactor of the preparation method of dinitronaphthalene of the present invention; Figure 2 is a schematic perspective view illustrating a shell unit, several reaction tubes and several mixing components of the reactor; 3 is a partial cross-sectional view illustrating a plurality of rectangular reaction channels of the reactor and a plurality of mixing assemblies respectively disposed in the rectangular reaction channels; 4 is a schematic cross-sectional view taken along IV-IV of FIG. 3; and Figure 5 is a schematic diagram illustrating a mixing element within one of the rectangular reaction channels.

3: reaction tube

31: Rectangular reaction channel

4: Hybrid Components

41: Comb deflector

411: Comb

412: Connector

Claims (11)

A preparation method of dinitronaphthalene, comprising the following steps: Naphthalene and nitric acid placed in a reactor are subjected to nitration reaction to obtain a solution containing dinitronaphthalene, wherein the reactor includes a rectangular reaction channel for the nitration reaction to be carried out, and a rectangular reaction channel arranged in the rectangular reaction channel The mixing assembly inside, and the mixing assembly has several stacked comb-shaped baffles, each comb-shaped baffle has several comb teeth, and the comb teeth of the comb-shaped baffles cooperate with each other The naphthalene and nitric acid are mixed with each other so that irregular flow occurs. The method for preparing dinitronaphthalene according to claim 1, wherein the comb teeth of the comb-shaped baffles are arranged in a stack, and the extension directions of the comb teeth of two adjacent comb-shaped baffles are opposite. The method for preparing dinitronaphthalene according to claim 2, wherein the extending directions of the comb teeth of each comb-shaped baffle are the same. The method for preparing dinitronaphthalene as claimed in claim 3, wherein each comb-shaped baffle further has a connector connecting the comb teeth, and the angle between each comb tooth and the connector is in the range of 30 degrees to 45 degrees. The preparation method of dinitronaphthalene as claimed in claim 3, wherein the distance between two adjacent comb teeth ranges from 1 mm to 4 mm. The preparation method of dinitronaphthalene according to claim 1, further comprising placing an organic solvent in the reactor. The preparation method of dinitronaphthalene as claimed in claim 6, wherein the organic solvent is dichloroethane. The preparation method of dinitronaphthalene as claimed in claim 6, wherein, based on the total amount of the naphthalene, the organic solvent and the nitric acid being 100 wt%, the content of the naphthalene ranges from 5 wt% to 10 wt%. The method for preparing dinitronaphthalene according to claim 1, further comprising cooling the solution containing dinitronaphthalene, so that the dinitronaphthalene is precipitated from the solution. The preparation method of dinitronaphthalene as claimed in claim 9, wherein the temperature range of this cooling treatment is 10°C to 20°C. A preparation method of dinitronaphthalene, comprising the following steps: Naphthalene and nitric acid placed in a reactor are subjected to a nitration reaction to obtain a solution containing dinitronaphthalene, wherein the reactor includes a plurality of rectangular reaction channels for the nitration reaction to be carried out, and a plurality of Mixing components in an equirectangular reaction channel, and each mixing component has several stacked comb-shaped guide plates, and each comb-shaped guide plate has a number of comb teeth, passing through the comb-shaped guide plates of the Equal comb teeth are matched to make the naphthalene and nitric acid flow irregularly and mix with each other.

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