阅读说明：本技术 一种利用填充床式反应器制备对氯邻硝基乙酰乙酰苯胺的方法 (Method for preparing p-chloro-o-nitroacetoacetanilide by using packed bed reactor ) 是由 张宗英 郝春艳 刘玲玲 李珂 高欢 崔子玉 于 2021-08-13 设计创作，主要内容包括：本发明属于化学合成领域,涉及一种利用填充床式反应器制备对氯邻硝基乙酰乙酰苯胺的方法,具体步骤为：将对氯邻硝基苯胺用甲苯溶解后,将双乙烯酮加入到反应体系中,搅拌均匀备用；反应液经泵以恒定的流速,从上端打入装有固体酸催化剂的填充床反应器中,反应液从底部流出,进入反应液收集器；检测合格之后,负压脱出大部分溶剂,降温结晶后,抽滤干燥可得到产物。与现有技术相比,本发明由于使用酸性阳离子交换树脂催化剂,可以实现催化剂的重复使用,从而达到连续生产；同时,由于催化剂比表面积大,催化活性高,使反应周期缩短,利于杂质控制,产品纯度高(98％),收率高(98％)。(The invention belongs to the field of chemical synthesis, and relates to a method for preparing p-chloro-o-nitroacetoacetanilide by using a packed bed reactor, which comprises the following specific steps: dissolving p-chloro-o-nitroaniline with toluene, adding diketene into a reaction system, and uniformly stirring for later use; pumping the reaction liquid into a packed bed reactor filled with a solid acid catalyst from the upper end at a constant flow rate through a pump, and enabling the reaction liquid to flow out from the bottom and enter a reaction liquid collector; and after the detection is qualified, most of the solvent is removed under negative pressure, and after cooling crystallization, the product can be obtained by suction filtration and drying. Compared with the prior art, the method can realize the repeated use of the catalyst due to the use of the acidic cation exchange resin catalyst, thereby achieving the continuous production; meanwhile, the catalyst has large specific surface area and high catalytic activity, so that the reaction period is shortened, the impurity control is facilitated, the product purity is high (98%), and the yield is high (98%).)

1. A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor is characterized by comprising the following steps: the method comprises the following specific steps:

firstly, dissolving p-chloro-o-nitroaniline by using toluene, adding diketene into a reaction system, and uniformly stirring for later use; pumping the reaction liquid into a packed bed reactor filled with a solid acid catalyst from the upper end at a constant flow rate through a pump, and enabling the reaction liquid to flow out from the bottom and enter a reaction liquid collector;

detecting that the residue of the p-chloro-o-nitroaniline in the reaction system is less than or equal to 1 percent, removing most of the solvent under negative pressure, cooling, crystallizing, and carrying out suction filtration and drying to obtain a product; if the detection is unqualified, the reaction liquid can be circularly pumped into the packed bed until the reaction tracking is qualified;

wherein the mass fraction of the p-chloro-o-nitroaniline toluene solution is 15-40%;

the molar ratio of the p-chloro-o-nitroaniline to the diketene is 1: 1.0-1.5;

the solid acid catalyst is one of acidic cation exchange resin, super-strong solid acid, zeolite molecular sieve and acidic clay; h in the p-chloro-o-nitroaniline and solid acid catalyst⁺The molar ratio of (A) to (B) is 1: 0.1-0.2;

the reaction temperature of the packed bed reactor is set to be 50-100 ℃.

2. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: the mass fraction of the p-chloro-o-nitroaniline toluene solution is 25 percent; the molar ratio of the p-chloro-o-nitroaniline to the diketene is 1: 1.15.

3. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: the solid acid catalyst is strong acid cation exchange resin, and the parachloro-o-nitroaniline and H in the solid acid catalyst⁺Is 1: 0.14.

4. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: the reaction temperature of the packed bed reactor is set to 80 ℃.

5. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: and the temperature of the cooling crystallization is 0-15 ℃, and then the filtration and the drying are carried out.

6. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 5, wherein: the temperature of the cooling crystallization is 0-5 ℃.

7. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: the used pump is one of a peristaltic pump, a constant flow plunger pump and a high-pressure constant flow double-plunger pump, and the total feeding speed is 10-40 mL/min.

8. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: the pump used was a peristaltic pump.

9. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 1, wherein: circularly applying the mother liquor obtained by suction filtration until the content of the finally obtained product is lower than 98 percent, and stopping applying; and meanwhile, repeatedly using the acidic resin catalyst until the p-chloro-o-nitroaniline residue in the tracking reaction solution is more than 1 percent, and stopping repeated use.

10. The method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor according to claim 9, wherein: the mother liquor is reused for 8 times.

Technical Field

The invention relates to the field of chemical synthesis, and particularly provides a method for preparing p-chloro-o-nitroacetoacetanilide by using a packed bed reactor.

Background

Quizalofop-p-ethyl is also called Jing-grass Ke and Xian hoe. Is an improved product after removing inactive optical isomer (L-body) in the process of synthesizing quizalofop-ethyl. Quizalofop-p-ethyl is a novel high-selectivity stem and leaf treating agent for dry farmland, has high selectivity between gramineous weeds and dicotyledonous crops, and has good control effect on gramineous weeds in broad leaf crop fields.

The other Chinese characters are acetyl p-chloro-o-nitroaniline and N- (4-chloro-2-nitrophenyl) -3-oxo-butyramide. The p-chloro-o-nitro-n-acetoacetanilide is an intermediate for synthesizing quizalofop-p-ethyl, the main raw materials for synthesizing the p-chloro-o-nitro-acetoacetanilide at present are p-chloro-o-nitroaniline and diketene, and the reaction equation is as follows:

the reaction mechanism is as follows:

the mature route for synthesizing the p-chloro-o-nitro-n-acetoacetanilide is mainly as follows: the method comprises the steps of preparing p-chloro-o-nitroacetoanilide by using a one-pot reaction method under the heating condition of p-chloro-o-nitroaniline and diketene, wherein in the method, on one hand, the diketene is easy to generate self-polymerization reaction in an alkaline environment, the requirements on workshop equipment and reaction conditions are high, the production safety is poor, and the product has low purity due to large impurities; on the other hand, the catalyst is difficult to recycle and has high production cost. The applicant has proposed that a raw material with low toxicity and high safety is used to replace diketene to prepare p-chloro-o-nitroacetoacetanilide, but since diketene is still the most common raw material in the prior art, how to improve a preparation method using diketene as a raw material is still the research direction in the field, and based on the research direction, how to provide a synthetic method of p-chloro-o-nitroacetoacetanilide with simple operation, high production safety, low cost, high purity and high yield becomes an urgent problem to be solved.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for preparing p-chloro-o-nitroacetoacetanilide by using a packed bed reactor, which has the specific scheme that an acidic cation exchange resin catalyst is filled in a packed bed, reaction liquid is introduced into the packed bed at a certain flow rate, the catalytic reaction and the material transfer are realized under certain reaction conditions, and the more specific reaction steps are as follows: dissolving p-chloro-o-nitroaniline with toluene, adding diketene into the system, and uniformly stirring for later use; pumping the reaction liquid into a packed bed reactor filled with a solid acid catalyst from the upper end at a constant flow rate through a pump, and enabling the reaction liquid to flow out from the bottom and enter a reaction liquid collector; and after the detection is qualified, most of the solvent is removed under negative pressure, and after cooling crystallization, the product can be obtained by suction filtration and drying. Compared with the prior art, the method can realize the repeated use of the catalyst due to the use of the acidic cation exchange resin catalyst, thereby achieving the continuous production; meanwhile, the catalyst has large specific surface area and high catalytic activity, so that the reaction period is shortened, the impurity control is facilitated, the product purity is high (98%), and the yield is high (98%).

The specific technical scheme of the invention is as follows:

a method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

firstly, dissolving p-chloro-o-nitroaniline by using toluene, adding diketene into a reaction system, and uniformly stirring for later use; pumping the reaction liquid into a packed bed reactor filled with a solid acid catalyst from the upper end at a constant flow rate through a pump, and enabling the reaction liquid to flow out from the bottom and enter a reaction liquid collector;

detecting that the residual p-chloro-o-nitroaniline in the reaction system is less than or equal to 1 percent, removing most of solvent under negative pressure, cooling, crystallizing, carrying out suction filtration and drying to obtain a product, and if the detection is unqualified, circularly pumping the reaction liquid into a packed bed until the reaction tracking is qualified;

wherein the mass fraction of the p-chloro-o-nitroaniline toluene solution is 15-40%, preferably 25%;

the molar ratio of the p-chloro-o-nitroaniline to the diketene is 1:1.0-1.5, and the preferred molar ratio is 1: 1.15.

The solid acid catalyst is as follows: acidic cation exchange resin (strong acid cation exchange resin, weak acid cation exchange resin), and superstrong solid acid (C-SO)₃H、SO₄ ^2-/ZrO₂/TiO₂/Fe₃O₄、SO₄ ^2-/ZrO₂/Fe₃O₄、SO₃H-PGMA-(Fe₃O₄-OA)), a hydrogen zeolite molecular sieve (hydrogen ZSM-5 zeolite), an acid clay (kaolin, bentonite); the strong acid cation exchange resin is preferable, and more specifically, it can be selected from D001 macroporous strong acid resin or Na type 732 cation exchange resin (national drug group chemical Co., Ltd.), and Na type 732 cation exchange resin is most preferable.

H in the p-chloro-o-nitroaniline and solid acid catalyst⁺In a molar ratio of 1:0.1-0.2, preferably in a molar ratio of 1: 0.14. And the filling amount of the acidic cation exchange resin in the packed bed reactor is converted based on the molar ratio, so long as the requirements are met, wherein an implementable technical scheme is that the molar amount of hydrogen ions in 1g of resin is calculated according to an acid-base titration method, and then the acidic cation exchange resin with the corresponding weight is weighed according to the actually required hydrogen ions of the defined reaction and filled into the packed bed.

The total feeding speed of the pump is 10-40mL/min, the preferred feeding speed is 25mL/min, and the used pump can be one of a peristaltic pump, a constant flow plunger pump and a high-pressure constant flow double-plunger pump.

The reaction temperature of the packed bed reactor is set to be 50-100 ℃, and the preferred reaction temperature is 80 ℃.

The temperature reduction and crystallization temperature is 0-15 ℃, the preferable crystallization temperature is 0-5 ℃, and then the filtration and the drying are carried out.

Circulating water is introduced into the jacket during the reaction, so that the reaction temperature is controlled;

circularly applying the mother liquor obtained by suction filtration until the content of the finally obtained product is lower than 98 percent, and stopping applying; the mother liquor is applied for 1 to 9 times, and the preferable application time is 8 times; and meanwhile, repeatedly using the resin catalyst until the p-chloro-o-nitroaniline residue in the tracking reaction liquid is more than 1 percent, and stopping repeatedly using the resin catalyst.

Compared with the prior art, the invention has the main advantages that:

the resin solid catalyst used in the invention has high catalyst load per unit volume and high catalytic efficiency, and simultaneously, due to the adsorption effect of the resin, the reaction mass transfer efficiency is extremely high, the reaction time is greatly reduced, the reaction efficiency and the product selectivity are obviously improved, the side reaction and the raw material waste are reduced, and the product yield and quality are greatly improved.

Secondly, the acidic cation exchange resin is used for filling the bed reactor, so that the influence caused by mechanical stirring can be avoided, and the use stability of the catalyst is improved.

In conclusion, the method is simple, convenient and safe to operate, has little environmental pollution, can reach the content of more than 98 percent, has the yield of more than 98 percent, is far beyond the traditional synthetic method, and obtains good technical effect.

Drawings

FIG. 1 is a schematic diagram of the preparation process of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following examples, but it should not be construed that the scope of the above subject matter is limited to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention, and the following embodiments are all completed by adopting the conventional prior art except for the specific description.

Example 1

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.5, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to the formula of p-chloro-o-nitroaniline and H in hydrogen type ZSM-5 zeolite⁺Filling a hydrogen type ZSM-5 zeolite molecular sieve into a packed bed at a molar ratio of 1: 0.2;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, and tracking the residual 31.0 percent of the p-chloro-o-nitroaniline raw material; it can be seen that the catalytic effect of the hydrogen type ZSM-5 zeolite is not ideal.

Example 2

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.5, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to the H in p-chloro-o-nitroaniline and acidic clay kaolin⁺Filling an acidic clay kaolin catalyst into a packed bed at a molar ratio of 1: 0.2;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) and detecting the reaction liquid collected in the collector, tracking the residual 97.0 percent of the p-chloro-o-nitroaniline raw material, wherein the catalytic effect of the acid clay kaolin is poor, and the conversion rate of the raw material is very low.

Example 3

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.5, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling D001 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.14;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, and tracking the residual 7.0 percent of the p-chloro-o-nitroaniline raw material. Compared with hydrogen type ZSM-5 zeolite and acid clay kaolin, the D001 acid cation exchange resin as the catalyst has very obvious improvement.

Example 4

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.0, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.2;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in a collector, tracking the residual 4.2 percent of the p-chloro-o-nitroaniline raw material, removing two thirds of the solvent under negative pressure, cooling to 10-15 ℃ by using an ice water bath, keeping for 30min, and detecting the content of the p-chloro-o-nitroacetanilide and the yield of 93.4 percent after cold suction filtration and drying. When the Na-type 732 acidic cation exchange resin is used as a catalyst, the residual amount of raw materials is as low as 4.2%, the content of target products is as high as 97.4%, and the method can be applied to industrialization.

Example 5

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.15, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 50 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.2;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 50 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 10ml/min, and reacting the reaction liquid in the reactor;

(3) the reaction solution collected in the collector is detected, the residual 15.1% of the p-chloro-o-nitroaniline raw material is tracked, and the embodiment proves that when the reaction temperature is too low, the reaction rate is slow.

Example 6

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 40%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.3, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 85 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.1;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 85 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 15ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, tracking the residual 3.0 percent of the p-chloro-o-nitroaniline, removing two thirds of the solvent under negative pressure, cooling to 5-10 ℃ by using an ice water bath, keeping for 20min, and detecting the content of the p-chloro-o-nitroacetanilide to be 98.3 percent and the yield to be 94.2 percent after cold suction filtration and drying.

Example 7

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 15%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.5, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 70 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.2;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor at 70 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 15ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, after the reaction liquid is tracked to be qualified, removing two thirds of solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping the temperature for 10min, and detecting the content of the p-chloro-o-nitroacetoanilide to be 98.2% and the yield to be 93.2% after cold suction filtration and drying.

Example 8

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25 percent is prepared,adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.15, stirring and heating until the solid is completely dissolved to obtain a reaction solution, and controlling the temperature in the heating process to be below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.14;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 100 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 40ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, after the reaction liquid is tracked to be qualified, removing two thirds of solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping the temperature for 20min, and detecting the content of the p-chloro-o-nitroacetanilide by 97.8% and the yield of 92.1% after cold suction filtration and drying.

The embodiment verifies that the catalytic effect of the acid resin catalyst is obviously superior to that of hydrogen type ZSM-5 zeolite and acid clay kaolin, and the Na type acid resin in the acid resin catalyst has the best catalytic effect;

in addition, the reaction temperature, the raw material ratio, the feeding speed, the solid catalyst usage and the like all have obvious influence on the reaction.

By way of the above examples, the inventors have determined that the best manufacturing process is as in example 9 below:

example 9

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.15, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Filling Na type 732 acidic cation exchange resin into a packed bed at a molar ratio of 1: 0.14;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, after the reaction liquid is tracked to be qualified, removing two thirds of solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping the temperature for 10min, and detecting the content of the p-chloro-o-nitroacetanilide to be 99.2% and the yield to be 96.4% after cold suction filtration and drying.

The embodiment proves that under the reaction condition, the product content is high, and the yield is high; this reaction condition will be used as the preferable condition for the mother liquor application verification and the resin catalyst continuous use verification in the subsequent two examples.

Example 10

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene (mother liquor in example 9 is continuously used for 8 times, and the rest is made up by toluene) solution with the mass fraction of 25 percent, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.15, stirring and heating until all solids are dissolved to obtain reaction liquid, wherein the temperature in the heating process is controlled below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺Packing Na type 732 acidic cation exchange resin in a packed bed (continuously used for 3 times) at a molar ratio of 1: 0.14;

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in the collector, after the reaction liquid is tracked to be qualified, removing two thirds of solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping for 10min, carrying out cold suction filtration, drying, detecting the content of the p-chloro-o-nitroacetoanilide to be 98.1%, and obtaining the yield of 98.9%.

The embodiment proves that the mother liquor is used for 8 times, the content of the p-chloro-o-nitroacetoacetanilide is still higher than 98 percent, and the content of the product is lower than 98 percent after the mother liquor is used for 9 times.

Experiment number	Number of mother liquor application	Content of product/%)	Product yield/%
				1	New throwing	99.2	96.4
2	1	99	100.1
				3	2	99.1	98.2
4	3	98.8	98.4
				5	4	98.6	99.0
6	5	98.6	98.7
				7	6	98.4	98.6
8	7	98.2	98.1
				9	8	98.1	98.9
10	9	97.5	98.0

Example 11

A method for preparing p-chloro-o-nitro-acetoacetanilide by using a packed bed reactor comprises the following specific steps:

(1) preparing 250g of p-chloro-o-nitroaniline toluene solution with the mass fraction of 25%, adding diketene into the p-chloro-o-nitroaniline toluene solution according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.15, stirring and heating until the solid is completely dissolved to obtain reaction liquid, and controlling the temperature in the heating process to be below 80 ℃; according to p-chloro-o-nitroaniline and H in resin⁺The Na type 732 acidic cation exchange resin is packed in a packed bed (with a molar ratio of 1: 0.14)Use 10 more times);

(2) starting a heating circulation device, setting the temperature of the packed bed reactor to be 80 ℃, pumping the reaction liquid into the reactor by using a peristaltic pump according to the flow rate of 25ml/min, and reacting the reaction liquid in the reactor;

(3) detecting the reaction liquid collected in a collector, tracking the residual 1.8 percent of the p-chloro-o-nitroaniline raw material, removing two thirds of the solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping for 10min, and detecting the content of the p-chloro-o-nitroacetanilide to be 98.2 percent and the yield to be 95.3 percent after cold suction filtration and drying.

The example verifies that the acidic resin catalyst is continuously used for 10 times, and after the feed liquid passes through the packed bed again, the chloro-o-nitroaniline raw material is unqualified, and the catalyst treatment is needed at the moment.

Comparative example

The conventional reaction process of preparing p-chloro-o-nitro acetoacetanilide includes the following steps:

(1) according to the molar ratio of the p-chloro-o-nitroaniline to the diketene of 1:1.3, preparing 250g of 25 mass percent p-chloro-o-nitroaniline toluene solution into a 500mL four-neck flask, and adding 14 percent (mol%/p-chloro-o-nitroaniline) hydrochloric acid;

(2) slowly heating the system to 80 ℃, keeping the temperature for 2h, then carrying out liquid phase tracking detection, and if the detection is unqualified (the residue of the p-chloro-o-nitroaniline is less than or equal to 1%), continuing the heat preservation reaction;

(3) after the reaction system is tracked to be qualified, removing two thirds of solvent under negative pressure, cooling to 0-5 ℃ by using an ice water bath, keeping for 10min, and detecting the content of the p-chloro-o-nitroacetoacetanilide by 96.0 percent and the yield of 88.5 percent after cold suction filtration and drying.

The example verifies that the product content is not high and the yield is low by using the conventional kettle type reaction.