A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner

Abstract

The present application relates to the field of synthesizing 2,4-dichlorotoluene, and in particular to a method for catalyzing the directional synthesis of 2,4-dichlorotoluene by parachlorotoluene. A method for catalyzing the directional synthesis of 2,4-dichlorotoluene by parachlorotoluene, comprising the following preparation steps: taking parachlorotoluene, a catalyst and an auxiliary agent, mixing, using chlorine as a chlorine source, heat-insulating the reaction, collecting the reactants, separating the reactants and collecting 2,4-dichlorotoluene; the catalyst includes one or more of aluminum chloride, ferric chloride, antimony trichloride and zirconium tetrachloride. The present application adopts a homogeneous catalyst, which has the advantages of stable properties, convenient purchase channels, no need for further processing, low toxicity and high product yield; and the catalyst application system has mature industrial technology, many separation methods, and the convenience and safety of operation can be fully guaranteed, which can not only effectively improve the effect of catalytic synthesis, but also synthesize and separate 2,4-dichlorotoluene with higher purity and yield.

Description

Technical Field

[0001] The present application relates to the field of synthesizing 2,4-dichlorotoluene, and in particular to a method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner. Background Art

[0002] 2,4-Dichlorotoluene is a very important organic synthesis fine chemical intermediate. It can be used to synthesize a variety of organic chemical products such as 2,4-dichlorobenzoic acid, 2,4-dichlorobenzyl chloride, 2,4-dichlorobenzoyl chloride and 2,4-dichlorobenzaldehyde. It is the main raw material for pesticides such as pyrazol (herbicide), diniconazole (fungicide), and medicine ciprofloxacin.

[0003] Patent (CN201610622306.X) discloses a synthesis process of 2,4-dichlorotoluene, which is to mix ferric chloride and aluminum chloride, etc., and then go through cumbersome preparation steps such as power supply and loading. There are problems such as long preparation time, cumbersome steps and unstable catalyst performance. Patent (CN201610619322.3) discloses a production and processing process of 2,4-dichlorotoluene, which uses ReY type molecular sieve as a carrier, loads ferric chloride, zinc chloride and other substances, and obtains the catalyst through steps such as adsorption and drying. There are problems such as long preparation time and large differences in loading effects.

[0004] In view of the above-mentioned related technologies, the inventors found that the supported catalyst used in the existing 2,4-dichlorotoluene synthesis catalyst takes a long time to prepare and has complicated preparation steps. In particular, the catalyst performance is unstable, resulting in poor purity and yield of the final synthesized and separated 2,4-dichlorotoluene. Summary of the invention

[0005] In order to improve the defect of poor catalytic effect of existing 2,4-dichlorotoluene synthesis catalysts, the present application provides a method for catalyzing the directed synthesis of 2,4-dichlorotoluene from para-chlorotoluene.

[0006] The present application provides a method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner, using the following technical solution:

[0007] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: mixing para-chlorotoluene, a catalyst and an auxiliary agent, using chlorine gas as a chlorine source, carrying out a heat-insulating reaction, collecting reactants, separating the reactants and collecting 2,4-dichlorotoluene;

[0008] The catalyst includes one or more of aluminum trichloride, ferric trichloride, antimony trichloride and zirconium tetrachloride.

[0009] By adopting the above technical scheme, the present application optimizes the method for catalyzing para-chlorotoluene to direct the synthesis of 2,4-dichlorotoluene. The present application adopts one or more of aluminum trichloride, ferric trichloride, antimony trichloride and zirconium tetrachloride as catalysts. Since the catalyst used is a homogeneous catalyst, it has the advantages of stable properties, convenient purchase channels, no need for further processing, low toxicity and high product yield. In addition, the industrial technology of the catalyst application system is mature, there are many separation methods, and the convenience and safety of operation can be fully guaranteed. It can not only effectively improve the effect of catalytic synthesis, but also the purity and yield of the synthesized and separated 2,4-dichlorotoluene are higher.

[0010] Preferably, the catalyst further comprises a porous catalytic carrier, and the porous catalytic carrier comprises zeolite, porous silica particles or molecular sieve particles.

[0011] By adopting the above-mentioned technical scheme, the present application further optimizes the composition of the catalyst. By selecting a porous catalytic carrier to load the effective ingredients of the catalyst, on the one hand, the porous carrier provides a higher specific surface area, which can improve the catalytic activity of the catalyst; on the other hand, the porous catalytic carrier can improve the quality of the loaded catalyst active ingredients, thereby improving the catalytic performance of the catalyst.

[0012] Preferably, the porous catalytic carrier is a molecular sieve particle, and the molecular sieve particle is made by the following scheme:

[0013] Sodium hydroxide and potassium hydroxide are mixed and placed in a sodium aluminate solution, stirred and mixed, and a base liquid is collected;

[0014] Add silica sol to the base liquid, stir and mix to obtain a gel liquid;

[0015] The gel solution is taken and placed in a reaction kettle, crystallized and filtered, and the filter cake is collected to prepare a porous catalytic carrier.

[0016] By adopting the above technical scheme, the present application selects molecular sieve as the catalyst carrier for preparation, and the molecular sieve catalyst with optimized preparation scheme not only has good adsorption performance and specific surface area, but also has excellent catalytic activity.

[0017] Preferably, the catalyst is prepared by the following scheme:

[0018] Take one or more of aluminum trichloride, ferric trichloride, antimony trichloride or zirconium tetrachloride, heat and sublime, collect the sublimated gas and mix it with nitrogen to obtain reaction gas;

[0019] After the porous catalyst carrier is pretreated by heating, the reaction gas is blown through the porous catalyst. After the blowing is completed, the porous catalyst is allowed to stand and cool to room temperature under the protection of nitrogen, and then ground and sieved to prepare the catalyst.

[0020] By adopting the above technical scheme, the present application optimizes the preparation method of the catalyst. By using the active ingredients in the catalyst (aluminum trichloride, ferric chloride, antimony trichloride or zirconium tetrachloride) to sublimely coat the surface of the porous catalyst carrier, not only the structure of the prepared composite catalyst is more stable, but also the catalyst formed by surface coating in the present application has good catalytic performance, which effectively improves the purity and yield of the synthesized 2,4-dichlorotoluene.

[0021] Preferably, the porous catalyst carrier is pretreated by heating the porous catalyst to 400-450°C and calcining for 2 hours, and then cooling to 300-350°C by standing.

[0022] By adopting the above technical scheme, the present application further optimizes the technical scheme for catalyst preparation, and the technical scheme of preheating treatment can effectively improve the effective coating of the catalyst active substance on the catalyst carrier, thereby further improving the purity and yield of the synthesized 2,4-dichlorotoluene.

[0023] Preferably, the insulation reaction temperature is 30-60°C.

[0024] Preferably, the insulation reaction time is 3 to 6 hours.

[0025] In summary, this application has the following beneficial effects:

[0026] First, the present application optimizes the method for catalyzing para-chlorotoluene to direct the synthesis of 2,4-dichlorotoluene. The present application adopts one or more of aluminum trichloride, ferric trichloride, antimony trichloride and zirconium tetrachloride as catalysts. Since the catalyst used is a homogeneous catalyst, it has the advantages of stable properties, convenient purchase channels, no need for further processing, low toxicity and high product yield. In addition, the industrial technology of the catalyst application system is mature, there are many separation methods, and the convenience and safety of operation can be fully guaranteed. It can not only effectively improve the effect of catalytic synthesis, but also the purity and yield of the synthesized and separated 2,4-dichlorotoluene are higher.

[0027] Second, the present application further optimizes the composition of the catalyst by selecting a porous catalytic carrier to load the effective ingredients of the catalyst. On the one hand, the porous carrier provides a higher specific surface area, which can improve the catalytic activity of the catalyst; on the other hand, the porous catalytic carrier can improve the quality of the loaded catalyst active ingredients, thereby improving the catalytic performance of the catalyst.

[0028] Third, the present application optimizes the preparation method of the catalyst by using the active ingredients in the catalyst (aluminum trichloride, ferric chloride, antimony trichloride or zirconium tetrachloride) to modify the surface of the porous catalyst carrier by sublimation. Not only does this make the structure of the prepared composite catalyst more stable, but the catalyst formed by surface coating in the present application also has good catalytic performance, effectively improving the purity and yield of the synthesized 2,4-dichlorotoluene. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to the embodiments.

[0030] Preparation Example 1: Molecular sieve particles 1:

[0031] Take 3kg 0.5mol / L sodium hydroxide solution and 3.5kg 0.5mol / L potassium hydroxide solution, stir and mix, and place in 10.6kg mass fraction 5% sodium aluminate solution, stir and mix, and collect the base liquid;

[0032] Take 0.6 kg of silica sol with a solid content of 18% and add it to 6 kg of base liquid, stir and mix at room temperature to collect the gel liquid;

[0033] The gel solution was taken and placed in a reaction kettle. After crystallization reaction at 120° C. for 2 h, the solution was filtered and the filter cake was collected to prepare a porous catalytic carrier 1.

[0034] Preparation Example 2: Molecular sieve particles 2:

[0035] Take 3.8kg 0.5mol / L sodium hydroxide solution and 4kg 0.5mol / L potassium hydroxide solution, stir and mix, and place in 11kg 5% by mass sodium aluminate solution, stir and mix, and collect the base liquid;

[0036] Take 0.7 kg of silica sol with a solid content of 18% and add it to 7 kg of base liquid, stir and mix at room temperature to collect the gel liquid;

[0037] The gel solution was taken and placed in a reaction kettle, and crystallized at 120° C. for 2 h and then filtered to collect the filter cake, thereby preparing a porous catalytic carrier 2.

[0038] Preparation Example 3: Molecular sieve particles 3:

[0039] Take 4.5 kg of 0.5 mol / L sodium hydroxide solution and 4.5 kg of 0.5 mol / L potassium hydroxide solution, stir and mix, and place in 11.3 kg of 5% by mass sodium aluminate solution, stir and mix, and collect the base liquid;

[0040] Take 0.8 kg of silica sol with a solid content of 18% and add it to 8 kg of base liquid, stir and mix at room temperature to collect the gel liquid;

[0041] The gel solution was taken and placed in a reactor, and crystallized at 120° C. for 2 h and then filtered to collect the filter cake, thereby preparing a porous catalytic carrier 3.

[0042] Preparation Example 4

[0043] Take aluminum chloride, heat it to 250°C and keep it warm, collect the sublimated gas and mix it with nitrogen to obtain the reaction gas;

[0044] The porous catalytic carrier 1 is heated to 425°C and calcined for 2 hours. It is then allowed to stand and cool to 325°C. The reaction gas is purged through the porous catalyst at a purging rate of 450 mL / min. After the purging is completed, it is allowed to stand and cool to room temperature under nitrogen protection. The catalyst 1 is then ground and sieved.

[0045] Preparation Example 5

[0046] Take ferric chloride, heat it to 350℃ and keep it warm, collect the sublimated gas and mix it with nitrogen to obtain the reaction gas;

[0047] The porous catalytic carrier 1 is heated to 400°C and calcined for 2 hours. It is then allowed to stand and cool to 300°C. The reaction gas is purged through the porous catalyst at a purging rate of 450 mL / min. After the purging is completed, it is allowed to stand and cool to room temperature under nitrogen protection, and then ground and sieved to obtain the catalyst 2.

[0048] Preparation Example 6

[0049] Take antimony trichloride, heat it to 250℃ and keep it warm, collect the sublimated gas and mix it with nitrogen to obtain the reaction gas;

[0050] The porous catalytic carrier 1 was heated to 450°C and calcined for 2 hours. It was allowed to stand and cool to 350°C. The reaction gas was purged through the porous catalyst at a purging rate of 450 mL / min. After the purging was completed, it was allowed to stand and cool to room temperature under nitrogen protection. It was then ground and sieved to obtain the catalyst 3.

[0051] Preparation Example 7

[0052] After heating zirconium tetrachloride to 250°C and maintaining the temperature, the sublimated gas is collected and mixed with nitrogen to obtain the reaction gas;

[0053] The porous catalytic carrier 1 was heated to 425°C and calcined for 2 hours. The catalyst was allowed to stand and cool to 325°C. The reaction gas was purged through the porous catalyst at a purging rate of 450 mL / min. After the purging was completed, the catalyst was allowed to stand and cool to room temperature under nitrogen protection. The catalyst was then ground and sieved to obtain the catalyst 4.

[0054] Preparation Example 8

[0055] After heating zirconium tetrachloride to 375°C and maintaining the temperature, the sublimated gas is collected and mixed with nitrogen to obtain the reaction gas;

[0056] The porous catalytic carrier 2 was heated to 425°C and calcined for 2 hours. It was allowed to stand and cool to 325°C. The reaction gas was purged through the porous catalyst at a purging rate of 450 mL / min. After the purging was completed, it was allowed to stand and cool to room temperature under nitrogen protection. The catalyst 5 was then ground and sieved to obtain the catalyst 5.

[0057] Preparation Example 9

[0058] After heating zirconium tetrachloride to 250°C and maintaining the temperature, the sublimated gas is collected and mixed with nitrogen to obtain the reaction gas;

[0059] The porous catalytic carrier 3 was heated to 425°C and calcined for 2 hours. The catalyst was allowed to stand and cool to 325°C. The reaction gas was purged through the porous catalyst at a purging rate of 450 mL / min. After the purging was completed, the catalyst was allowed to stand and cool to room temperature under nitrogen protection. The catalyst was then ground and sieved to obtain the catalyst 6. Example

[0060] Example 1

[0061] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine gas at a reaction temperature of 30° C., adding 2 g of aluminum trichloride, reacting for 3 hours, separating the product, and thus preparing 2,4-dichlorotoluene.

[0062] Example 2

[0063] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine gas at a reaction temperature of 30° C., adding 2 g of ferric chloride, reacting for 3 hours, separating the product, and thus preparing 2,4-dichlorotoluene.

[0064] Example 3

[0065] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine gas at a reaction temperature of 30° C., adding 2 g of antimony trichloride, reacting for 3 hours, separating the product, and thus preparing 2,4-dichlorotoluene.

[0066] Example 4

[0067] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine gas at a reaction temperature of 30° C., adding 2 g of zirconium tetrachloride, reacting for 3 hours, separating the product, and thus preparing 2,4-dichlorotoluene.

[0068] Example 5

[0069] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine at a reaction temperature of 30° C., adding 2 g of a catalyst 1, reacting for 3 h, separating a product, and thus preparing 2,4-dichlorotoluene.

[0070] Example 6

[0071] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine at a reaction temperature of 30° C., adding 2 g of a catalyst 2, reacting for 3 h, separating a product, and thus preparing 2,4-dichlorotoluene.

[0072] Example 7

[0073] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine at a reaction temperature of 30° C., adding 2 g of a catalyst 3, reacting for 3 h, separating a product, and thus preparing 2,4-dichlorotoluene.

[0074] Example 8

[0075] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine at a reaction temperature of 30° C., adding 2 g of a catalyst 4, reacting for 3 h, separating the product, and thus preparing 2,4-dichlorotoluene.

[0076] Example 9

[0077] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine gas at a reaction temperature of 30° C., adding 2 g of a catalyst 5, reacting for 3 h, separating the product, and thus preparing 2,4-dichlorotoluene.

[0078] Example 10

[0079] A method for catalyzing para-chlorotoluene to synthesize 2,4-dichlorotoluene in a directional manner comprises the following preparation steps: adding 300 g of para-chlorotoluene into a 500 mL four-necked flask, introducing 150 mL / min of chlorine at a reaction temperature of 30° C., adding 2 g of a catalyst 6, reacting for 3 h, separating the product, and thus preparing 2,4-dichlorotoluene.

[0080] Comparative Example

[0081] Comparative Example 1

[0082] A method for synthesizing 2,4-dichlorotoluene, compared with Example 1, uses an equal mass of zeolite as a catalyst for catalytic treatment.

[0083] Performance testing

[0084] The 2,4-dichlorotoluene prepared in Examples 1 to 10 and Comparative Example 1 was tested, specifically the yield and purity of 2,4-dichlorotoluene. The test results are shown in Table 1 below:

[0085] Table 1 Performance test table

[0086]

[0087] Combining the data of Examples 1 to 10 and Comparative Example 1, it can be found that by optimizing the type of catalyst, first, by optimizing the method for catalyzing the directional synthesis of 2,4-dichlorotoluene from para-chlorotoluene, the present application uses one or more of aluminum trichloride, ferric trichloride, antimony trichloride and zirconium tetrachloride as a catalyst. Since the catalyst used is a homogeneous catalyst, it has the advantages of stable properties, convenient purchase channels, no need for further processing, low toxicity and high product yield; and the catalyst application system has mature industrial technology, many separation methods, and the convenience and safety of operation can be fully guaranteed, which can not only effectively improve the effect of catalytic synthesis, but also the purity and yield of the synthesized and separated 2,4-dichlorotoluene are higher.

[0088] At the same time, the present application further optimizes the composition of the catalyst by selecting a porous catalytic carrier to load the effective ingredients of the catalyst. On the one hand, the porous carrier provides a higher specific surface area, which can improve the catalytic activity of the catalyst; on the other hand, the porous catalytic carrier can improve the quality of the loaded catalyst active ingredients, thereby improving the catalytic performance of the catalyst.

[0089] Finally, the present application optimizes the preparation method of the catalyst by using the active ingredients in the catalyst (aluminum trichloride, ferric chloride, antimony trichloride or zirconium tetrachloride) to modify the surface of the porous catalyst carrier by sublimation. Not only is the structure of the prepared composite catalyst more stable, but the catalyst formed by surface coating in the present application has good catalytic performance, which effectively improves the purity and yield of the synthesized 2,4-dichlorotoluene.

[0090] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for catalyzing the directional synthesis of 2,4-dichlorotoluene by p-chlorotoluene, characterized in that: The method comprises the following preparation steps: mixing para-chlorotoluene and a catalyst, using chlorine gas as a chlorine source, carrying out a heat-insulating reaction, collecting reactants, separating the reactants and collecting 2,4-dichlorotoluene; The catalyst includes one or more of aluminum trichloride, ferric trichloride, antimony trichloride and zirconium tetrachloride; The catalyst also includes a porous catalyst support; The porous catalyst carrier is a molecular sieve particle, and the molecular sieve particle is made by the following scheme: Sodium hydroxide and potassium hydroxide are mixed and placed in a sodium aluminate solution, stirred and mixed, and a base liquid is collected; Add silica sol to the base liquid, stir and mix to obtain a gel liquid; The gel solution is taken and placed in a reactor, crystallized and filtered, and the filter cake is collected to prepare a porous catalyst carrier; the catalyst is prepared by the following scheme: Take one or more of aluminum trichloride, ferric trichloride, antimony trichloride or zirconium tetrachloride, heat and sublime, collect the sublimated gas and mix it with nitrogen to obtain reaction gas; After the porous catalyst carrier is pretreated by heating, the reaction gas is purged through the porous catalyst carrier. After the purging is completed, the porous catalyst carrier is allowed to stand and cool to room temperature under nitrogen protection, and then ground and sieved to prepare the catalyst. The porous catalyst carrier is pretreated by heating the porous catalyst carrier to 400-450°C, heat-insulating and calcining for 2 hours, and then allowed to stand and cool to 300-350°C.

2. The method for catalyzing the directional synthesis of 2,4-dichlorotoluene by para-chlorotoluene according to claim 1, characterized in that: The insulation reaction temperature is 30-60°C.

3. The method for catalyzing the directional synthesis of 2,4-dichlorotoluene by p-chlorotoluene according to claim 1, characterized in that: The heat preservation reaction time is 3 to 6 hours.

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