阅读说明：本技术 一种以均三甲苯为原料合成均三甲基苯胺的方法 (Method for synthesizing mesitylene by using mesitylene as raw material ) 是由 贾建洪 左英壮 蒋见睿 王丹凤 佘远斌 于 2021-09-24 设计创作，主要内容包括：本发明公开了一种以均三甲苯为原料合成均三甲基苯胺的方法,本发明以过量的均三甲苯为底物,均三甲苯既作溶剂又作原料,发烟硝酸为硝化剂,多聚磷酸作为脱水剂,氢气作所得硝化产品还原剂,设计一套绿色经济的反应工艺流程,以此来制备均三甲基苯胺。本发明使用均三甲苯原料作为反应溶剂,更加绿色环保,反应速率更快,无副产物生成,总收率更高并且作溶剂的均三甲苯可以回收循环使用,后处理简单,可得到纯度较高的油状均三甲基苯胺产品。(The invention discloses a method for synthesizing mesitylene by using mesitylene as a raw material. The method uses the mesitylene raw material as the reaction solvent, is more environment-friendly, has faster reaction rate, no byproduct, higher total yield, simple post-treatment and capability of recycling the mesitylene used as the solvent and obtaining the oily mesitylene product with higher purity.)

1. A method for synthesizing mesitylene by taking mesitylene as a raw material is characterized by comprising the following steps:

1) in a reactor, taking mesitylene of a formula (I) as a substrate, mixing fuming nitric acid and polyphosphoric acid at a low temperature of 0-10 ℃, dropwise adding the mixture into the reactor, and washing off residual phosphoric acid in a solution after reaction to obtain a mixed reaction liquid A containing a compound of a formula (II) and a compound of a formula (I);

2) adding a compound (I) into the reaction liquid A obtained in the step 1) to dilute the reaction liquid A until the mass concentration of a compound (II) is 10-30%, adding the diluted reaction liquid A into a reaction kettle, adding a catalyst, replacing the reaction kettle with nitrogen, replacing the nitrogen in the reaction kettle with hydrogen, performing hydrogenation reduction reaction, continuously supplementing hydrogen during the hydrogenation reduction reaction, and obtaining a reaction liquid B containing a compound of a formula (III) and a compound of a formula (I) after the reaction is finished;

3) and (3) carrying out post-treatment on the reaction solution B to obtain a mesitylene product.

2. The method for synthesizing mesitylene according to claim 1, wherein in step 1), the mass ratio of mesitylene to fuming nitric acid is 3-5: 1.

3. the method for synthesizing mesitylene according to claim 1, wherein in step 1), the mass ratio of polyphosphoric acid to fuming nitric acid is 2-4: 1.

4. the method for synthesizing mesitylene according to claim 1, wherein the step 1) of washing away the residual phosphoric acid in the solution comprises:

adding saturated saline solution into the liquid after reaction, quenching, separating to obtain an organic phase and an aqueous phase, adding saturated saline solution again, separating, and repeatedly washing for three times.

5. The method for synthesizing mesitylene according to claim 1, wherein the reaction time in step 1) is 4-6 h.

6. The method for synthesizing mesitylene according to claim 1, wherein in the step 2), nitrogen is substituted by nitrogen, hydrogen is substituted by nitrogen in the reaction kettle, then hydrogen is introduced until the pressure in the reaction kettle is 2-4 MPa, and the reaction kettle is heated to 100-150 ℃ for hydrogenation reduction reaction.

7. The method for synthesizing mesitylene according to claim 6, wherein the time of hydrogenation reduction reaction in step 2) is 8-12 h.

8. The method for synthesizing mesitylene according to claim 1, wherein the catalyst in step 2) is Raney nickel, Pd/C or Pt/Al₂O₃。

9. The method for synthesizing mesitylene according to claim 1, wherein the post-treatment in step 3) comprises:

and cooling the reaction liquid B, dropwise adding an acidic solution into the reaction liquid B, stirring the compound (III) to form salt, adding water to dissolve the salt formed by the compound (III), layering the aqueous phase with a mesitylene solution, filtering to remove the catalyst, recovering and recycling, separating the solution to obtain an aqueous solution of the salt formed by the mesitylene and the mesitylene, recovering and recycling, adding an alkaline solution into the salt solution of the mesitylene, separating the mesitylene out, and separating the solution to obtain a mesitylene product.

10. The method for synthesizing mesitylene according to claim 9, wherein in step 3), the acidic solution is sulfuric acid solution or hydrochloric acid solution;

the alkaline solution is sodium hydroxide solution or sodium carbonate solution.

Technical Field

The invention relates to the field of organic synthesis, in particular to a green and economic preparation method and technical field for synthesizing mesitylene by using mesitylene as a raw material.

Background

Mesitylene (CAS:88-05-1), having the following chemical formula:

the mesitylene (1, 3, 5-trimethylbenzene) is nitrated to prepare 2, 4, 6-trimethylnitrobenzene, and then reduced to obtain 2-amino mesitylene (also known as mesitylene). The 2-amino mesitylene is an intermediate of weak acid and reactive dyes, and dyes synthesized by the 2-amino mesitylene, such as weak acid brilliant blue RAW, reactive emerald green, reactive brilliant blue and the like, have bright color and good uniformity, can be used for dyeing wool, silk and polyamide fiber fabrics, can be dyed in a single color, and can also be spliced with other weak acid dyes.

The synthesis of mesitylene with mesitylene as material includes two main steps:

(1) nitrating mesitylene with mixed nitric acid and sulfuric acid to obtain 2, 4, 6-trimethyl nitrobenzene;

(2) hydrogenating and catalyzing 2, 4, 6-trimethyl nitrobenzene to obtain mesitylene.

At present, the domestic production of 2, 4, 6-trimethyl nitrobenzene adopts a traditional intermittent nitration method, namely, sulfuric acid, nitric acid and water are prepared into mixed acid, then the mixed acid and the mesitylene are nitrated at the temperature of below 10 ℃, the obtained product is stood for layering, waste acid is discharged, and then the 2, 4, 6-trimethyl nitrobenzene is obtained by washing and neutralizing with water. Most of the batch nitration methods adopt kettle type batch production, the reaction speed is slow, the process is not easy to control, the yield is low, the product yield is low, the waste acid is difficult to treat and utilize, the resource waste is serious, and in addition, the batch nitration is easy to explode if the operation is improper, thereby causing safety accidents.

At present, the common 2, 4, 6-trimethylnitrobenzene in China is reduced to prepare the mesitylene, mainly hydrogenation reduction is used as the main part, the existing hydrogenation process is generally finished by adopting an intermittent hydrogenation kettle, and the hydrogenation method is more conventional and more mature in operation. At present, the common hydrogenation reduction needs to dissolve the solid raw material by an external solvent, but the method is relatively complicated in operation, and besides increasing the cost, the problems of solvent recovery, environmental pollution and the like need to be considered. Therefore, the invention discloses a novel catalytic hydrogenation process for preparing the mesitylene, which has important economic and environmental protection values.

Disclosure of Invention

In order to overcome the defects, a green nitration process taking a mesitylene raw material as a solvent and polyphosphoric acid as a dehydrating agent and a new process for synthesizing mesitylene are provided. The method is characterized in that mesitylene is selected to be greatly excessive and used as a reaction raw material and a reaction solvent, fuming nitric acid is used as a nitrating agent, hydrogen is used as a reducing agent, and Pd/C is used as a catalyst, and in order to achieve the purpose, the method adopts the following technical scheme:

the invention provides a novel method for synthesizing mesitylene by using mesitylene as a raw material, which comprises the following reaction processes:

(I) mesitylene; (II) 2, 4, 6-trimethylnitrobenzene; (III) mesitylene;

the invention designs a set of green and economic reaction process flow by using excessive mesitylene as a substrate, using mesitylene as a solvent and a raw material, fuming nitric acid as a nitrating agent, polyphosphoric acid as a dehydrating agent and hydrogen as an obtained nitration product reducing agent, so as to prepare the mesitylene.

A method for synthesizing mesitylene by taking mesitylene as a raw material comprises the following steps:

1) in a reactor, taking mesitylene of a formula (I) as a substrate, mixing fuming nitric acid and polyphosphoric acid at a low temperature of 0-10 ℃, dropwise adding the mixture into the reactor, and washing off residual phosphoric acid in a solution after reaction to obtain a mixed reaction liquid A containing a compound of a formula (II) and a compound of a formula (I);

2) adding a compound (I) into the reaction liquid A obtained in the step 1) to dilute the reaction liquid A until the mass concentration of a compound (II) is 10% -30% (preferably 20%), adding the diluted reaction liquid A into a reaction kettle after the dilution is finished, adding a catalyst, replacing the reaction kettle with nitrogen, replacing the nitrogen in the reaction kettle with hydrogen, carrying out hydrogenation reduction reaction, continuously supplementing hydrogen during the hydrogenation reduction reaction, and obtaining a reaction liquid B containing a compound of a formula (III) and a compound of a formula (I) after the reaction is finished;

3) and (3) carrying out post-treatment on the reaction solution B to obtain a mesitylene product.

In the step 1), the compound (I) is used as a reaction raw material and a reaction solvent, and mechanical stirring is started.

The mass ratio of the mesitylene to fuming nitric acid is 3-5: 1, the mesitylene is obviously excessive and is used as a raw material and a reaction solvent.

The mass ratio of the polyphosphoric acid to the fuming nitric acid is 2-4: 1, mixing the two solutions at low temperature under ice bath condition.

The dropping speed is 1 drop in 1 second to 1 drop in 2 seconds.

The washing of the residual phosphoric acid in the solution specifically comprises:

adding saturated saline solution into the reacted liquid for quenching, separating the solution to obtain an organic phase and an aqueous phase, adding the saturated saline solution again, separating the solution, and repeatedly washing the solution for three times so as to wash away the residual phosphoric acid in the solution.

The reaction time is 4-6 h (preferably 5 h).

In the step 2), nitrogen is selected to replace the reaction kettle, nitrogen in the reaction kettle is replaced by hydrogen, then hydrogen is introduced until the pressure in the reaction kettle is 2-4 MPa (preferably 3MPa), and the reaction kettle is heated to 100 ℃ -150 ℃ (preferably 120 ℃) to carry out hydrogenation reduction reaction.

The time of the hydrogenation reduction reaction is 8h to 12h (preferably 10 h).

The catalyst is Raney nickel, Pd/C, Pt/Al₂O₃(preferably Pd/C).

In step 3), the post-processing comprises:

and cooling the reaction liquid B, dropwise adding an acidic solution into the reaction liquid B, stirring the compound (III) to form salt, adding water to dissolve the salt formed by the compound (III), layering the aqueous phase with a mesitylene solution, filtering to remove the catalyst, recovering and recycling, separating the solution to obtain an aqueous solution of the salt formed by the mesitylene and the mesitylene, recovering and recycling, adding an alkaline solution into the salt solution of the mesitylene, separating the mesitylene out, and separating the solution to obtain a mesitylene product.

The acid solution is sulfuric acid solution or hydrochloric acid solution.

The alkaline solution is sodium hydroxide solution or sodium carbonate solution.

The mass fraction of the acidic substance in the acidic solution (i.e. the acidic substance aqueous solution) is more than 30%.

The mass fraction of the alkaline substance in the alkaline solution (namely the alkaline substance aqueous solution) is more than 30 percent.

Specifically, the method comprises the following steps:

adding excessive compound (I) serving as a substrate into a four-neck flask at room temperature, wherein the compound (I) serves as a reaction raw material and a reaction solvent, and starting mechanical stirring. Mixing fuming nitric acid and polyphosphoric acid at low temperature, controlling the temperature to be 0-10 ℃, adding the mixture into a dropping funnel, slowly dropping the mixture into a four-neck flask, controlling the dropping speed to be 1 drop to 2 drops in 1 second, and reacting for 4-6 h (preferably 5h) to obtain a mixed reaction liquid A containing a compound of a formula (II) and a compound of a formula (I); adding a saturated saline solution into the reaction solution A for quenching, separating the solution to obtain an organic phase and an aqueous phase, adding the saturated saline solution again, separating the solution, and repeatedly washing the solution for three times so as to wash away the residual phosphoric acid in the solution.

Adding the compound (I) into the reaction liquid A obtained in the last step to dilute the reaction liquid A until the concentration of the compound (II) is 10-30 percent (preferably 20 percent), adding the reaction liquid A into a stainless steel autoclave after the dilution is finished, and adding Raney nickel, Pd/C, Pt/Al₂O₃The catalyst (preferably Pd/C) is replaced by nitrogen with 0.4MPa for 3-5 times (preventing explosion caused by direct introduction of hydrogen), and the nitrogen in the reaction kettle is replaced by hydrogen with 0.5MPa for 3-5 timesIntroducing hydrogen until the pressure in the kettle is 2-4 MPa (preferably 3MPa), checking the air tightness of the device, heating the reaction kettle to 100-150 ℃ (preferably 120 ℃) to perform hydrogenation reduction reaction, continuously replenishing hydrogen in the reaction kettle until the hydrogen is not consumed for one hour continuously (the pressure of the hydrogen in the reaction kettle is not reduced for one hour continuously), keeping the reaction time between 8 h-12 h (preferably 10h), cooling to room temperature after the reaction is finished (discharging at high temperature is not needed to prevent trimethylaniline from being oxidized), and obtaining reaction liquid B containing the compound of the formula (III) and the compound of the formula (I); cooling the reaction liquid B to room temperature, dropwise adding an acidic solution into the reaction liquid B to enable the compound (III) to be stirred and salified, adding water to dissolve the salt formed by the compound (III), layering the aqueous phase with a mesitylene solution, filtering to remove the catalyst (for recycling), separating liquid to obtain an aqueous solution of the salt formed by the mesitylene and the mesitylene (for recycling), adding an alkaline solution into the salt solution of the mesitylene to enable the mesitylene to be separated out, and separating liquid to obtain a mesitylene product (yellow oily liquid).

The mass ratio of the mesitylene to fuming nitric acid is 3-5 (preferably 4); the mass ratio of the dehydrating agent polyphosphoric acid to fuming nitric acid is 2-4 (preferably 3); the acid solution is a hydrochloric acid solution or a sulfuric acid solution (preferably a sulfuric acid solution); the alkaline solution is a sodium hydroxide solution or a sodium carbonate solution (preferably a sodium hydroxide solution), and the amount ratio of the mesitylene solution of the mesitylene to the acid substance in the acid solution is 1.1-1.3 (preferably 1.2); the sulfuric acid solution is a sulfuric acid aqueous solution with the mass fraction of more than or equal to 30%, and preferably the mass fraction of concentrated sulfuric acid is 50%; the sodium hydroxide solution is a sodium hydroxide solution with the mass fraction of more than or equal to 30%, and the concentrated sulfuric acid is preferably 50%.

Compared with the prior art, the invention has the following advantages:

the invention provides a new synthesis process and a post-treatment method of mesitylene. The method has the advantages that the mesitylene raw material is used as a reaction solvent, the environment is protected, the reaction rate is high, no by-product is generated, the total yield is high, the mesitylene used as the solvent can be recycled, the post-treatment is simple, and the oily mesitylene product with high purity can be obtained.

The oxidation by-product generated by oxidizing mesitylene can be effectively reduced by using polyphosphoric acid instead of the traditional concentrated sulfuric acid as a dehydrating agent; the method of using excessive mesitylene as solvent can effectively reduce dinitration by-products generated by dinitration of mesitylene, and the reason of ice water bath in the dropping process is that the reaction temperature needs to be controlled because of the heat release of nitration reaction.

Compared with a methanol solution of the mesitylene, the mesitylene solution of the mesitylene can save more organic solvents, is more economic and environment-friendly, can play the same role in the hydrogenation catalytic reduction process, and has the advantages of being more economic and environment-friendly compared with the traditional process, such as the mesitylene can be recycled.

Drawings

FIGS. 1 and 2 are HPLC charts of 2-nitromesitylene and mesitylene, respectively, in example 1;

FIG. 3 is a process flow diagram of the whole bench process.

Detailed Description

The mesitylene product prepared in this example was analyzed by liquid chromatography to obtain a product containing 99.02% by mass of mesitylene, and the liquid chromatogram is shown in the figure. The chromatographic conditions for the liquid chromatography of the mesitylene product prepared in this example were as follows:

the liquid chromatograph model is as follows: agilent 1260; mobile phase: methanol: water-40: 60(0min) → 40: 60(2min) → 80: 20(20min) → 80: 20(30min) → 90: 10(35min), flow rate: 1ml/min, column temperature: 28 ℃; detection wavelength: 220 nm.

Example 1:

adding 36.06g (0.3mol) of mesitylene into a 100mL four-neck round-bottom flask at room temperature of 25 ℃, starting mechanical stirring, weighing 6.43g (0.1mol) of fuming nitric acid, mixing with 12.86g of polyphosphoric acid under ice bath (below 10 ℃), slowly dripping into the four-neck round-bottom flask through a dropping funnel, controlling dripping speed to be about 2 seconds per drop, then reacting for 4 hours at 25 ℃, heating to 35 ℃ for reacting for one hour, adding 20mL of saturated saline solution to quench the reaction, shaking in a separating funnel, standing for layering, separating liquid, taking an organic layer, adding 20mL of saturated saline solution again, washing for 3 times in the same way, and removing phosphoric acid in the organic layer. 38.68g of 2, 4, 6-trimethylnitrobenzene in mesitylene are finally obtained, 14.64g of product being obtained in 88.62% yield and 100% HPLC purity.

Adding 29.22g of mesitylene into the reaction liquid obtained in the last step to dilute the reaction liquid until the concentration of 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 5), adding the solution into a stainless steel autoclave after the dilution is finished, adding 1.12g of Raney nickel catalyst (65.2% of Raney nickel and 34.8% of water), replacing the autoclave 4 times by 0.3MPa of nitrogen, replacing the nitrogen in the autoclave 3 times by 0.4MPa of hydrogen, introducing hydrogen until the pressure in the autoclave is 4MPa, checking the airtightness of the device, heating the autoclave to 100 ℃ for hydrogenation reduction reaction for 8 hours to obtain a mesitylene solution of mesitylene, cooling the reaction liquid to room temperature, filtering and separating the reaction liquid and the catalyst (0.88 g of the catalyst is recovered), dripping 84.14g of a 35% hydrochloric acid solution into the reaction liquid, heating, starting stirring, the method comprises the steps of generating mesitylene hydrochloride, adding water to dissolve the mesitylene hydrochloride, layering an aqueous phase and a mesitylene solution, separating the layers to obtain a mesitylene hydrochloride aqueous solution and mesitylene (48.5 g of recovered mesitylene), adding 22.55g of a 50% sodium carbonate solution into the mesitylene hydrochloride aqueous solution, heating, stirring, and separating the layers to obtain 10.95g of yellow oily mesitylene, wherein the yield is 91.39%, and the HPLC purity is 98.33%.

As shown in FIG. 1, 23.202min showed a peak (2-nitromesitylene) and 29.145min showed a peak (mesitylene). As shown in FIG. 2, 17.299min peaked (mesitylene).

As shown in fig. 3, is a process flow diagram of the whole set of the lab-on-a-chip process.

Example 2:

adding 36.06g (0.3mol) of mesitylene into a 100mL four-neck round-bottom flask at room temperature of 25 ℃, starting mechanical stirring, weighing 6.43g (0.1mol) of fuming nitric acid, mixing with 19.29g of polyphosphoric acid under ice bath (below 10 ℃), slowly dripping into the four-neck round-bottom flask through a dropping funnel, controlling dripping speed to be about 2 seconds per drop, then reacting for 5 hours at 25 ℃, heating to 35 ℃ for reacting for one hour, adding 20mL of saturated saline solution to quench the reaction, shaking in a separating funnel, standing for layering, separating liquid, taking an organic layer, adding 20mL of saturated saline solution again, washing for 3 times in the same operation, and removing phosphoric acid in the organic layer. 39.44g of a mesitylene solution of 2, 4, 6-trimethylnitrobenzene were obtained to give 15.4g of product in 93.22% yield and 100% HPLC purity.

Adding 31.98g of mesitylene into the reaction liquid obtained in the last step for dilution until the concentration of 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 5), adding the solution into a stainless steel autoclave after dilution is finished, adding 2.07g of Pd/C catalyst (Pd/C37.1%, moisture is 62.9%), replacing the autoclave 4 times with 0.3MPa nitrogen, replacing the nitrogen in the autoclave 3 times with 0.4MPa hydrogen, introducing hydrogen until the pressure in the autoclave is 3MPa, checking the airtightness of the device, heating the autoclave to 120 ℃ for hydrogenation reduction reaction for 10 hours to obtain a mesitylene solution of mesitylene, cooling the reaction liquid to room temperature, filtering and separating the reaction liquid and the catalyst (recovering 1.78g of the catalyst), dropwise adding 31.42g of sulfuric acid solution with the concentration of 50% into the reaction liquid, heating, starting stirring to generate mesitylene sulfate, adding water to dissolve the mesitylene sulfate, layering an aqueous phase and a mesitylene solution, separating to obtain a mesitylene sulfate aqueous solution and mesitylene (48.8 g of recovered mesitylene), adding 16.4g of 50% sodium hydroxide solution into the mesitylene sulfate aqueous solution, heating, stirring, and separating to obtain 11.99g of yellow oily mesitylene, wherein the yield is 95.12%, and the HPLC purity is 98.65%.

Example 3:

adding 36.06g (0.3mol) of mesitylene into a 100mL four-neck round-bottom flask at room temperature of 25 ℃, starting mechanical stirring, weighing 6.43g (0.1mol) of fuming nitric acid, mixing with 25.72g of polyphosphoric acid under ice bath (below 10 ℃), slowly dripping into the four-neck round-bottom flask through a dropping funnel, controlling dripping speed to be about 2 seconds per drop, then reacting for 6 hours at 25 ℃, heating to 35 ℃ for reacting for one hour, adding 20mL of saturated saline solution to quench the reaction, shaking in a separating funnel, standing for layering, separating liquid, taking an organic layer, adding 20mL of saturated saline solution again, washing for 3 times in the same way, and removing phosphoric acid in the organic layer. 39.45g of 2, 4, 6-trimethylnitrobenzene in mesitylene were finally obtained, giving 15.41g of product in 93.28% yield and 100% HPLC purity.

Adding 32.02g of mesitylene into the reaction liquid obtained in the last step for dilution until the concentration of the 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of the 2, 4, 6-trimethylnitrobenzene to the mesitylene is 1: 5), adding the solution into a stainless steel autoclave after the dilution is finished, and adding 1.18g of Pt/Al₂O₃Catalyst (Pt/Al)₂O₃65.5 percent of water, 34.5 percent of water), replacing the nitrogen in the reaction kettle for 4 times by using 0.3MPa of nitrogen, replacing the nitrogen in the reaction kettle for 3 times by using 0.4MPa of hydrogen, finally filling hydrogen to the pressure of 2MPa, then introducing the hydrogen to the pressure of 3MPa in the kettle, checking the air tightness of the device, raising the temperature of the reaction kettle to 150 ℃ to carry out hydrogenation reduction reaction for 12 hours to obtain a mesitylene solution of mesitylene, cooling the reaction solution to room temperature, filtering and separating the reaction solution and a catalyst (recovering 1.01g of the catalyst), dropwise adding 19.08g of a 60 percent sulfuric acid solution into the reaction solution, heating, starting stirring to generate mesitylene sulfate, adding water to dissolve the mesitylene sulfate, layering a water phase with the mesitylene solution, separating the liquid to obtain a mesitylene sulfate water solution and mesitylene (recovering 48.6g of the mesitylene), adding 16.17g of a 60 percent sodium hydroxide solution into the mesitylene sulfate water solution, heating, stirring, and liquid separation gave mesitylene 11.87g as yellow oil, 94.11% yield, 98.57% HPLC purity.

Example 4:

at room temperature of 25 ℃, 96.16g (0.8mol) of mesitylene is added into a 250mL four-neck round-bottom flask, mechanical stirring is started, 12.86g (0.2mol) of fuming nitric acid and 25.72g of polyphosphoric acid are weighed and mixed under ice bath (below 10 ℃), the mixture is slowly dripped into the four-neck round-bottom flask through a dripping funnel, the dripping speed is controlled to be about 1 second per drip, the mixture reacts for 4 hours at 25 ℃ after dripping is finished, the temperature is increased to 35 ℃ for reaction for one hour, 40mL of saturated saline solution is added for quenching reaction, the mixture is shaken in a separating funnel, the mixture is kept stand for layering, an organic layer is separated, 40mL of saturated saline solution is added again, the operation is carried out for 3 times, and the phosphoric acid in the organic layer is removed. 100.69g of a mesitylene solution of 2, 4, 6-trimethylnitrobenzene were obtained to give 28.57g of product in 86.47% yield and 99.5% HPLC purity.

Adding 180.1g of mesitylene into the reaction liquid obtained in the last step to dilute the reaction liquid until the concentration of 2, 4, 6-trimethylnitrobenzene is 10% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 10), adding the solution into a stainless steel autoclave after the dilution is finished, adding 2.19g of Raney nickel catalyst (65.2% of Raney nickel and 34.8% of water), replacing the autoclave with 0.3MPa of nitrogen for 4 times, replacing the nitrogen in the autoclave with 0.4MPa of hydrogen for 3 times, introducing hydrogen until the pressure in the autoclave is 2MPa, checking the airtightness of the device, heating the autoclave to 100 ℃ for hydrogenation reduction reaction for 12 hours to obtain a mesitylene solution of mesitylene, cooling the reaction liquid to room temperature, filtering and separating the reaction liquid and the catalyst (1.73 g of the catalyst is recovered), adding 53.76g of 40% sulfuric acid solution into the reaction liquid, heating, stirring is started to generate mesitylene sulfate, water is added to dissolve the mesitylene sulfate, an aqueous phase is layered with a mesitylene solution, liquid separation is carried out to obtain a mesitylene sulfate aqueous solution and mesitylene (246.5 g of mesitylene is recovered), 43.89g of a 50% sodium hydroxide solution with the concentration is added into the mesitylene sulfate aqueous solution, heating and stirring are carried out, liquid separation is carried out to obtain 21.01g of yellow oily mesitylene, the yield is 89.98%, and the HPLC purity is 98.51%.

Example 5:

at room temperature of 25 ℃, 96.16g (0.8mol) of mesitylene is added into a 250mL four-neck round-bottom flask, mechanical stirring is started, 12.86g (0.2mol) of fuming nitric acid and 38.58g of polyphosphoric acid are weighed and mixed under ice bath (below 10 ℃), the mixture is slowly dripped into the four-neck round-bottom flask through a dropping liquid funnel, the dripping speed is controlled to be about 1 second per drop, the mixture reacts for 5 hours at 25 ℃ after the dripping is finished, the temperature is increased to 35 ℃ for reaction for one hour, 40mL of saturated saline solution is added for quenching reaction, the mixture is shaken in a separating funnel, the mixture is kept stand for layering, liquid is separated, an organic layer is taken, 40mL of saturated saline solution is added again, and the operation is carried out for 3 times in the same way, so that the phosphoric acid in the organic layer is removed. 102.33g of 2, 4, 6-trimethylnitrobenzene in mesitylene were finally obtained, giving 30.21g of product, 91.4% yield and 99.5% HPLC purity.

Adding 37.78g of mesitylene into the reaction liquid obtained in the last step for dilution until the concentration of 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 5), adding the solution into a stainless steel autoclave after dilution is finished, adding 4.07g of Pd/C catalyst (Pd/C37.1%, moisture is 62.9%), replacing the autoclave 4 times with 0.3MPa nitrogen, replacing the nitrogen in the autoclave 3 times with 0.4MPa hydrogen, introducing hydrogen until the pressure in the autoclave is 3MPa, checking the airtightness of the device, heating the autoclave to 120 ℃ for hydrogenation reduction reaction for 10 hours to obtain a mesitylene solution of mesitylene, cooling the reaction liquid to room temperature, filtering and separating the reaction liquid and the catalyst (recovering 2.73g of the catalyst), dropwise adding 43.01g of a 50% sulfuric acid solution into the reaction liquid, heating, starting stirring to generate mesitylene sulfate, adding water to dissolve the mesitylene sulfate, layering an aqueous phase and a mesitylene solution, separating the layers to obtain a mesitylene sulfate aqueous solution and mesitylene (103.5 g of mesitylene is recovered), adding 35.11g of a 50% sodium hydroxide solution into the mesitylene sulfate aqueous solution, heating, stirring, and separating the layers to obtain 23.11g of yellow oily mesitylene, wherein the yield is 93.45%, and the HPLC purity is 98.65%.

Example 6:

at room temperature of 25 ℃, 96.16g (0.8mol) of mesitylene is added into a 250mL four-neck round-bottom flask, mechanical stirring is started, 12.86g (0.2mol) of fuming nitric acid and 51.44g of polyphosphoric acid are weighed and mixed under ice bath (below 10 ℃), the mixture is slowly dripped into the four-neck round-bottom flask through a dropping liquid funnel, the dripping speed is controlled to be about 1 second per drop, the mixture reacts for 6 hours at 25 ℃ after the dripping is finished, the temperature is increased to 35 ℃ for reaction for one hour, 40mL of saturated saline solution is added for quenching reaction, the mixture is shaken in a separating funnel, the mixture is kept stand for layering, liquid is separated, an organic layer is taken, 40mL of saturated saline solution is added again, and the operation is carried out for 3 times in the same way, so that the phosphoric acid in the organic layer is removed. 102.48g of a mesitylene solution of 2, 4, 6-trimethylnitrobenzene were obtained to give 30.36g of product in 91.9% yield and 99.4% HPLC purity.

Removing 13.3g of mesitylene from the reaction solution obtained in the last step, concentrating until the concentration of 2, 4, 6-trimethylnitrobenzene is 30% (the molar ratio of the 2, 4, 6-trimethylnitrobenzene to the mesitylene is 3: 10), adding the solution into a stainless steel autoclave after the dilution is finished, and adding 2.32g of Pt/Al₂O₃Catalyst (Pt/Al)₂O₃65.5 percent of water, 34.5 percent of water), replacing the nitrogen in the reaction kettle for 4 times by using 0.3MPa of nitrogen, replacing the nitrogen in the reaction kettle for 3 times by using 0.4MPa of hydrogen, introducing hydrogen until the pressure in the kettle is 4MPa, checking the airtightness of the device, heating the reaction kettle to 150 ℃ to perform hydrogenation reduction reaction for 8 hours to obtain a mesitylene solution of mesitylene, cooling the reaction solution to room temperature, filtering and separating the reaction solution and the catalyst (recovering 2.73g of the catalyst), dropwise adding 51.61g of 60 percent sulfuric acid solution into the reaction solution, heating, starting stirring to generate mesitylene sulfate, adding water to dissolve the mesitylene sulfate solution, layering the water phase and the mesitylene solution, separating to obtain a mesitylene sulfate aqueous solution and mesitylene (recovering 103.5g of mesitylene), adding 42.13g of 60 percent sodium hydroxide solution into the mesitylene sulfate aqueous solution, heating, stirring, and liquid separation gave 23.08g of mesitylene as a yellow oil, 92.88% yield, and 98.65% HPLC purity.

Example 7:

at room temperature of 25 ℃, 240.38g (2mol) of mesitylene is added into a 500ml four-neck round-bottom flask, mechanical stirring is started, 25.72g (0.4mol) of fuming nitric acid is weighed and mixed with 102.88g of polyphosphoric acid under ice bath (below 10 ℃), the mixture is slowly dripped into the four-neck round-bottom flask through a dropping funnel, 2 drops are added in a dropping speed controlled for about 1 second, then the mixture is reacted for 5 hours at 25 ℃, the temperature is increased to 35 ℃ for reaction for one hour, 100ml of saturated saline solution is added for quenching reaction, the mixture is shaken in a separating funnel, standing is carried out for layering, liquid separation is carried out, an organic layer is taken, 100ml of saturated saline solution is added again, and the operation is carried out for 3 times for removing the phosphoric acid in the organic layer. 253.66g of a mesitylene solution of 2, 4, 6-trimethylnitrobenzene were finally obtained, giving 61.27g of product, a yield of 92.7% and an HPLC purity of 99.4%.

Diluting the reaction liquid obtained in the last step by adding 30.51g of mesitylene until the concentration of 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 5), adding the solution into a stainless steel autoclave after dilution is finished, adding 8.26g of Pd/C catalyst (Pd/C37.1%, moisture is 62.9%), replacing the autoclave by 0.3MPa nitrogen for 4 times, replacing the nitrogen in the autoclave by 0.4MPa hydrogen for 3 times, finally filling hydrogen to the pressure of 2MPa, then introducing hydrogen to the pressure of 2MPa in the autoclave, checking the airtightness of the device, heating the autoclave to 120 ℃ for hydrogenation reduction reaction, reacting for 10h to obtain a mesitylene solution of mesitylene, cooling the reaction liquid to room temperature, filtering and separating the reaction liquid and the catalyst (5.79 g of the catalyst is recovered), adding 87.24g of 50% sulfuric acid solution dropwise into the reaction liquid, heating, starting stirring to generate mesitylene sulfate, adding water to dissolve the mesitylene sulfate, layering an aqueous phase and a mesitylene solution, separating to obtain a mesitylene sulfate aqueous solution and mesitylene (215.11 g of recovered mesitylene), adding 71.21g of 50% sodium hydroxide solution into the mesitylene sulfate aqueous solution, heating, stirring, and separating to obtain 47.88g of yellow oily mesitylene, wherein the yield is 93.01%, and the HPLC purity is 98.81%.

Example 8:

215.11g of mesitylene and 5.79g of Pd/C catalyst (37.1% Pd/C, 62.9% water) were recovered from example 7 and were ready for use. At room temperature, 215.11g (1.79mol) of mesitylene is added into a 500mL four-neck round-bottom flask, mechanical stirring is started, 25.72g (0.4mol) of fuming nitric acid is weighed and mixed with 77.16g of polyphosphoric acid under ice bath (below 10 ℃), the mixture is slowly dripped into the four-neck round-bottom flask through a dropping funnel, 2 drops are added into the mixture for about 1 second by controlling the dripping speed, then the mixture is reacted for 5 hours at 25 ℃, the temperature is increased to 35 ℃ for reaction for one hour, 80mL of saturated saline solution is added for quenching reaction, the mixture is shaken in a separating funnel, standing and layering are carried out, an organic layer is obtained, 80mL of saturated saline solution is added again, and the operation is carried out for 3 times by the same operation, so that the phosphoric acid in the organic layer is removed. 162.09g of a mesitylene solution of 2, 4, 6-trimethylnitrobenzene were obtained to give 59.64g of product in 90.3% yield and 99.1% HPLC purity.

Adding 54.88g of mesitylene into the reaction solution obtained in the last step to dilute the reaction solution until the concentration of 2, 4, 6-trimethylnitrobenzene is 20% (the molar ratio of 2, 4, 6-trimethylnitrobenzene to mesitylene is 1: 5), adding the solution into a stainless steel autoclave after the dilution is finished, adding 8.26g (additionally adding 2.47g) of Pd/C catalyst (Pd/C37.1% and water content is 62.9%), replacing the autoclave with 0.3MPa of nitrogen for 4 times, replacing the nitrogen in the autoclave with 0.4MPa of hydrogen for 3 times, finally filling hydrogen until the pressure is 2MPa, then introducing the hydrogen until the pressure in the autoclave is 2MPa, checking the airtightness of the device, heating the autoclave to 120 ℃ to carry out hydrogenation reduction reaction for 10h to obtain a mesitylene solution of mesitylene, cooling the reaction solution to room temperature of 25 ℃, filtering and separating the reaction solution and the catalyst (5.68 g of recovered catalyst), 87.24g of 50% sulfuric acid solution is dropwise added into the reaction solution, heating and stirring are started to generate mesitylene sulfate, water is added to dissolve the mesitylene sulfate, a water phase and a mesitylene solution are layered, liquid separation is carried out to obtain a mesitylene sulfate water solution and mesitylene (213.89 g of recovered mesitylene), 71.21g of 50% sodium hydroxide solution with concentration is added into the mesitylene sulfate water solution, heating and stirring are carried out, liquid separation is carried out to obtain 45.99g of yellow oily mesitylene, the yield is 94.22%, and the HPLC purity is 98.95%.