阅读说明：本技术 一种4,4’-二(苯基异丙基)二苯胺的制备方法 (Preparation method of 4,4' -di (phenylisopropyl) diphenylamine ) 是由 毕莹 刘光奇 张会京 范小鹏 孙春光 于 2021-09-24 设计创作，主要内容包括：本发明提供了一种4,4’-二(苯基异丙基)二苯胺的制备方法。该制备方法包括：将包含二苯胺、催化剂及反应溶剂的溶液A以及α-甲基苯乙烯注入微通道反应器进行反应,得到式I的4,4’-二(苯基异丙基)二苯胺；其中,二苯胺、α-甲基苯乙烯以及式I的结构式分别如下：其中,溶液A及α-甲基苯乙烯以二苯胺与α-甲基苯乙烯摩尔比为1:1.5～2.5,50-100ml/min的总流速注入微通道反应器。本发明的4,4’-二(苯基异丙基)二苯胺制备方法采用微通道反应器取代传统釜式反应器,反应过程安全,大幅度缩短了反应时间,提高了生产效率。(The invention provides a preparation method of 4,4' -bis (phenylisopropyl) diphenylamine. The preparation method comprises the following steps: injecting a solution A containing diphenylamine, a catalyst and a reaction solvent and alpha-methylstyrene into a microchannel reactor for reaction to obtain 4,4' -bis (phenylisopropyl) diphenylamine shown in the formula I; wherein, diphenylamine, alpha-methylstyrene and structural formulas of formula I are respectively as follows:)

1. A method for preparing 4,4' -bis (phenylisopropyl) diphenylamine, comprising:

injecting a solution A containing diphenylamine, a catalyst and a reaction solvent and alpha-methylstyrene into a microchannel reactor for reaction to obtain 4,4' -bis (phenylisopropyl) diphenylamine shown in a formula I;

wherein the diphenylamine, the alpha-methylstyrene and the structural formula of formula I are respectively as follows:

the solution A and the alpha-methyl styrene are injected into the microchannel reactor at a total flow rate of 50-100ml/min, wherein the molar ratio of diphenylamine to alpha-methyl styrene is 1: 1.5-2.5.

2. The method as claimed in claim 1, wherein the solution A is heated to 160 ℃ and 100 ℃ before being injected into the microchannel reactor.

3. The preparation method according to claim 1 or 2, wherein the solution A and the alpha-methylstyrene are injected into the microchannel reactor in a molar ratio of diphenylamine to alpha-methylstyrene of 1: 1.8-2.1.

4. The process of claim 3, wherein the alpha-methylstyrene further contains a polymerization inhibitor prior to being fed into the microchannel reactor.

5. The process according to claim 3 or 4, wherein the reaction time of the solution A and the α -methylstyrene in the microchannel reactor is 10 to 60 minutes.

6. The method of claim 5, further comprising, after completion of the reaction:

collecting the reaction liquid flowing out of the microchannel reactor, filtering and washing;

carrying out reduced pressure distillation on the water washing liquid, and recovering the reaction solvent and alpha-methyl styrene for recycling;

and purifying the residue obtained after the reduced pressure distillation treatment to obtain the purified 4,4' -bis (phenylisopropyl) diphenylamine.

7. The process according to any one of claims 1 to 5, characterized in that the catalyst is a Lewis acid or activated clay, wherein the amount of Lewis acid is 1 to 10% by mole of the diphenylamine and the amount of activated clay is 1 to 10% by mass of the diphenylamine.

8. The preparation method of claim 7, wherein the Lewis acid is selected from one or more of aluminum trichloride and zinc trichloride ferric trichloride.

9. The process according to claim 7, wherein when the catalyst is activated clay, the particle size of the activated clay is 800 mesh or more.

10. The production method according to any one of claims 1 to 9, characterized in that the reaction solvent is any one or more of nitrobenzene, chlorobenzene, o-dichlorobenzene, dichloromethane, dichloroethane; wherein the dosage of the reaction solvent is 1-8 times of the theoretical yield of the 4,4' -bis (phenylisopropyl) diphenylamine.

Technical Field

The invention relates to the technical field of synthesis of diphenylamine antioxidants, and particularly relates to a preparation method of 4,4' -bis (phenylisopropyl) diphenylamine.

Background

4,4' -di (phenyl isopropyl) diphenylamine is one of a few nontoxic, tasteless and light antioxidant varieties in amine antioxidants, can be used for protecting natural rubber and synthetic rubber such as butylbenzene, isoprene, chloroprene and butyl from aging caused by heat, light and ozone, and has a good synergistic effect with sulfur-containing antioxidants.

Currently, 4,4' -bis (phenylisopropyl) diphenylamine is synthesized mainly from diphenylamine and α -methylstyrene as starting materials. The synthesis route is mainly two, one is that diphenylamine and alpha-methyl styrene react under the catalysis of Lewis acid in the absence of solvent or inert solvent; secondly, under the protection of nitrogen, diphenylamine and alpha-methyl styrene are subjected to solvent-free reaction under the catalysis of activated clay. Since the raw material alpha-methylstyrene is easily polymerized by heating, in the above synthesis method, a slow dropwise manner is usually adopted to prevent the alpha-methylstyrene from polymerizing, or the dosage of the alpha-methylstyrene is increased to increase the yield of 4,4' -bis (phenylisopropyl) diphenylamine.

The above preparation method has problems that: 1. the feeding amount of the alpha-methyl styrene is larger, so that the unit consumption of the alpha-methyl styrene is increased; 2. the polymerization reaction of the alpha-methyl styrene can release a large amount of polymerization heat, thereby causing huge potential safety hazard to the production process; 3. the nitrogen protection in the reaction increases the difficulty of operation and the production cost.

Disclosure of Invention

In order to solve the problems of easy self-polymerization, long reaction time, high unit consumption, potential safety hazard and the like of alpha-methylstyrene in the prior art, the invention mainly aims to provide a method for preparing 4,4' -bis (phenylisopropyl) diphenylamine by using a microchannel reactor.

In order to achieve the above objects, the present invention provides a method for preparing 4,4' -bis (phenylisopropyl) diphenylamine using a microchannel reactor. The preparation method comprises the following steps: injecting a solution A containing diphenylamine, a catalyst and a reaction solvent and alpha-methylstyrene into a microchannel reactor for reaction to obtain 4,4' -bis (phenylisopropyl) diphenylamine shown in a formula I;

wherein, diphenylamine, alpha-methylstyrene and structural formulas of formula I are respectively as follows:

wherein the solution A and the alpha-methyl styrene are injected into the microchannel reactor at a total flow rate of 50-100ml/min, wherein the molar ratio of diphenylamine to alpha-methyl styrene is 1: 1.5-2.5.

Further, the solution A is heated to 100-160 ℃ before being injected into the microchannel reactor.

Further, the solution A and the alpha-methyl styrene are injected into the microchannel reactor in a molar ratio of diphenylamine to alpha-methyl styrene of 1: 1.8-2.1.

Further, the alpha-methylstyrene feed further contains a polymerization inhibitor prior to being fed into the microchannel reactor.

Further, the reaction time of the solution A and the alpha-methyl styrene in the microchannel reactor is 10 to 60 minutes.

In the specific embodiment provided by the present invention, after the completion of the above reaction, the method further comprises the following steps: collecting reaction liquid flowing out of the microchannel reactor, filtering and washing; carrying out reduced pressure distillation on the water washing liquid, and recovering the reaction solvent and the alpha-methyl styrene for recycling; and purifying the residue obtained after the reduced pressure distillation treatment to obtain the 4,4' -bis (phenylisopropyl) diphenylamine.

In the specific embodiment provided by the invention, the catalyst is Lewis acid or activated clay, wherein the dosage of the Lewis acid is 1-10% of the molar weight of diphenylamine; the dosage of the activated clay is 1 to 10 percent of the mass of the diphenylamine. Preferably, the lewis acid is one or more selected from the group consisting of aluminum trichloride, zinc trichloride and iron trichloride.

Further, when the catalyst is activated clay, the particle size of the activated clay is 800 mesh or more.

In the specific embodiment provided by the invention, the reaction solvent is any one or mixture of more of nitrobenzene, chlorobenzene, o-dichlorobenzene, dichloromethane and dichloroethane; preferably, the amount of the reaction solvent is 1 to 8 times of the theoretical amount of 4,4' -bis (phenylisopropyl) diphenylamine produced.

By applying the preparation method of the 4,4' -bis (phenylisopropyl) diphenylamine provided by the invention, the microchannel reactor is used for replacing the traditional kettle-type reactor, the usage amount of alpha-methylstyrene is effectively reduced, the generation of alpha-methylstyrene autopolymer is reduced, the reaction selectivity is improved, the reaction time is greatly shortened, and the reaction safety is improved.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background section, the problem of auto-polymerization of alpha-methylstyrene and potential safety hazard in the synthesis process of 4,4 '-bis (phenylisopropyl) diphenylamine in the prior art is solved by the present invention, which provides a method for preparing 4,4' -bis (phenylisopropyl) diphenylamine by using a microchannel reactor, the method comprising: respectively injecting a solution A containing diphenylamine, a catalyst and a reaction solvent and alpha-methylstyrene into a microchannel reactor for chemical reaction to obtain the 4,4' -bis (phenylisopropyl) diphenylamine. Wherein the solution A and the alpha-methyl styrene are injected into the microchannel reactor at a total flow rate of 50-100ml/min, wherein the molar ratio of diphenylamine to alpha-methyl styrene is 1: 1.5-2.5.

Although microchannel reactors have large specific surface areas and excellent heat and mass transfer capabilities, most reactions containing heterogeneous catalysts are not suitable for use with microchannel reactors due to their tendency to clog. In addition, because the traditional reaction kettle and the microchannel reactor have great difference, the reaction conditions and processes adopted by the traditional reaction kettle are not necessarily suitable for the microchannel reaction, such as the proportion of reaction raw materials, the sample injection mode, the sample injection temperature and the like. Therefore, through several research and development activities, the inventor creatively selects the feeding mode, the feeding proportion and the sample injection speed of the reaction raw materials, and realizes the safe and high-yield production and preparation of the 4,4' -bis (phenylisopropyl) diphenylamine by utilizing the microchannel reactor. The preparation method of the 4,4' -bis (phenylisopropyl) diphenylamine provided by the invention comprises the steps of firstly preparing reaction substrates into separate reaction raw material liquids, respectively injecting the reaction raw material liquids into a microchannel reactor, wherein the reaction substrates can be instantly and uniformly mixed in the microchannel reactor and effectively prevent alpha-methylstyrene from self-polymerizing, and secondly, controlling the molar ratio of diphenylamine to alpha-methylstyrene to be 1: 1.5-2.5, and injecting the solution A and the alpha-methylstyrene into the microchannel reactor under the condition that the total flow rate of the solution A and the alpha-methylstyrene is 50-100ml/min, thereby further and accurately controlling the selectivity of products and the reaction heat release. The reaction yield of the 4,4' -bis (phenylisopropyl) diphenylamine is improved to 90 percent from about 75 percent of the reaction yield of the traditional process by controlling the sample injection mode, the sample injection proportion and the sample injection speed of the reaction raw materials. The preparation method not only reduces the usage amount of the alpha-methyl styrene, but also obviously improves the reaction yield, and is suitable for industrial large-scale production.

The chemical reaction equation related to the invention is as follows:

in the embodiment of the present invention, the solution A is heated to a temperature of between 100 ℃ and 160 ℃ before being injected into the microchannel reactor. Heating the solution A to the above temperature to dissolve or uniformly disperse the raw materials and the catalyst in the solvent; and the reaction raw materials are respectively prepared into reaction liquid, so that the phenomenon that the alpha-methyl styrene is heated to the temperature to generate self-polymerization is avoided. Once the solution A with the temperature of 100-160 ℃ is mixed with the alpha-methylstyrene in the microchannel reactor, the reaction liquid is quickly heated to the reaction temperature, thereby further accelerating the reaction speed and shortening the reaction process. Further, the heating of the solution a may be performed under a nitrogen blanket, and the solution a may be sufficiently stirred.

In the specific embodiment provided by the invention, the solution A and the alpha-methylstyrene are injected into the microchannel reactor at a molar ratio of diphenylamine to alpha-methylstyrene of 1:1.8-2.1 and a total flow rate of 50-100 ml/min. In the preferable proportion, the reaction selectivity is higher, and the reaction yield is higher.

In a preferred embodiment of the present invention, a polymerization inhibitor is further added (contained) to the alpha-methylstyrene feedstock prior to its introduction into the microchannel reactor. The polymerization inhibitor is added into the alpha-methyl styrene raw material, so that the alpha-methyl styrene can be prevented from self-polymerization before being added into the microchannel reactor. Meanwhile, due to the existence of the polymerization inhibitor, the self-polymerization phenomenon of the alpha-methyl styrene in the microchannel reactor is also obviously reduced. 0-150ppm of polymerization inhibitor in the alpha-methyl styrene raw material. Although the invention provides a specific mode in which the polymerization inhibitor is added into the alpha-methylstyrene raw material to realize the polymerization inhibition effect, equivalent modifications, such as adding into the solution A or independently adding into a microchannel reactor, are within the protection scope of the invention. The polymerization inhibitor which can be used in the present application is p-tert-butylcatechol, 2, 6-dinitro-p-cresol, 4, 6-dinitro-2-sec-butylphenol, etc.

The inventors of the present application have also found that the degree of substitution of the reaction product can be further controlled by controlling the reaction time of solution a and α -methylstyrene in the microchannel reactor. Preferably, in the technical scheme provided by the application, if the reaction time is controlled to be 10-60 minutes, the yield of the target product (disubstituted) is higher.

In the specific embodiment provided by the invention, after the chemical reaction is completed, the method further comprises the steps of collecting the reaction liquid flowing out of the microchannel reactor, filtering and washing; carrying out reduced pressure distillation on the water washing liquid, and recovering the reaction solvent and the alpha-methyl styrene for recycling; and purifying the residue obtained after the reduced pressure distillation treatment to obtain the 4,4' -bis (phenylisopropyl) diphenylamine.

Further, the purification method is to add the residue into petroleum ether for crystallization treatment.

In the specific embodiment provided by the invention, the catalyst is Lewis acid or activated clay, and preferably at least one or more of aluminum trichloride, zinc trichloride and ferric trichloride. Furthermore, the dosage of the Lewis acid is 1 to 10 percent of the molar weight of the diphenylamine, and the dosage of the activated clay is 1 to 10 percent of the mass of the diphenylamine.

When the catalyst is activated clay, the particle size of the activated clay is preferably 800 mesh or more. In a preferred embodiment, the activated clay is first screened to a mesh size of 800 mesh or greater prior to being placed in the microchannel reactor. By optimizing the size of catalyst particles, the microchannel reactor can be effectively prevented from being blocked in a large area, so that the reaction is smoother.

In the specific embodiment provided by the invention, the reaction solvent is any one or mixture of more of nitrobenzene, chlorobenzene, o-dichlorobenzene, dichloromethane and dichloroethane; preferably, the amount of the reaction solvent is 1 to 8 times of the theoretical amount of 4,4' -bis (phenylisopropyl) diphenylamine produced. Although the present invention has been described with reference to the above reaction solvents, the present invention is not limited to the above reaction solvents, and the reaction solvents that can be used in the chemical reaction are within the scope of the present invention.

As can be seen from the above description, the molar ratio of diphenylamine to alpha-methylstyrene is controlled to be 1: 1.5-2.5 by controlling the sample introduction mode, the sample introduction ratio and the sample introduction speed of the reaction raw materials, and even the reaction ratio can be controlled to be within the range of 1:1.8-2.1, so that the usage amount of alpha-methylstyrene is greatly reduced.

Another advantage of the present invention is that the reaction temperature is lower and the reaction time is significantly reduced. The reaction temperature of the solution A and the alpha-methyl styrene in the microchannel reactor is 100-160 ℃, which is lower than the reaction temperature of the traditional reaction kettle. Moreover, the dripping time of the traditional process is generally 3-6 hours, the subsequent heat preservation time is more than 1 hour, the total reaction time is about 5-8 hours, and the reaction time of the invention can be only 10-60 minutes.

The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention. The operations referred to in the examples are, unless otherwise specified, all those of ordinary skill in the art.

Raw material and reactor

The diphenylamine, alpha-methylstyrene and other reagents used in the present invention are commercially available, and can also be prepared according to techniques known in the art.

The microchannel reactor used in the examples of the present invention was corning G1-6FM (commercially available from corning reactor technologies, inc.). The flow range is wide: 15-250 ml/min. The temperature and pressure ranges were: the temperature is-60 ℃ to 200 ℃, and the pressure can be born by 18 kg.

Comparative example

170.0g (1.00mol) of diphenylamine, 9.5g (0.07mol) of aluminum chloride and 800mL of nitrobenzene were charged in this order into a 2000mL four-necked flask equipped with an electric stirrer, a thermometer and a constant-pressure dropping funnel, stirred under nitrogen and heated to 140 ℃. 331.0g (2.80mol) of alpha-methylstyrene are added dropwise at 140 ℃ over 6 h. And reacting for 4 h. Filtering while the solution is hot, and washing with water. The solvent is removed by reduced pressure distillation, and the alpha-methyl styrene is recycled. The residue was crystallized from petroleum ether to give 4,4' -bis (phenylisopropyl) diphenylamine as a white powdery solid in a yield of 79%.

EXAMPLES 1-8 preparation of diphenylamine antioxidant 4,4' -bis (phenylisopropyl) diphenylamine

Example 1

170.0g (1.00mol) of diphenylamine, 8.0g (0.06mol) of aluminum chloride and 800mL of nitrobenzene were successively charged into a 1000mL four-necked flask equipped with an electric stirrer and a thermometer, and the mixture was stirred under nitrogen atmosphere and heated to 140 ℃ to obtain a solution A. 237.0g (2.00mol) of alpha-methylstyrene are introduced into a 500mL round-bottom flask. The two liquids were pumped into a microchannel reactor at a total flow rate of 80mL/min diphenylamine to alpha-methylstyrene molar ratio of 1: 2.0. The reaction liquid stays for 20min at 140 ℃, flows out of the microchannel reactor and flows into a receiving device. Filtering while the solution is hot, and washing with water. The solvent is removed by reduced pressure distillation, and the alpha-methyl styrene is recycled. The residue was crystallized from petroleum ether to give 4,4' -bis (phenylisopropyl) diphenylamine as a white powdery solid in a yield of 91%.

Example 2

The difference from example 1 is that 2.7g (0.02mol) of aluminum chloride was used as the catalyst, 213.0g (1.80mol) of alpha-methylstyrene was used, the two liquids were injected into a microchannel reactor at a molar ratio of diphenylamine to alpha-methylstyrene of 1:1.8 and a total flow rate of 50ml/min, chlorobenzene was used as the reaction solvent, and the reaction time was 60 minutes, to finally obtain 4,4' -bis (phenylisopropyl) diphenylamine with a yield of 86%.

Example 3

The difference from example 1 is that 8.2g (0.06mol) of zinc chloride, 189.0g (1.60mol) of alpha-methylstyrene are used, and the two liquids are injected into the microchannel reactor at a molar ratio of diphenylamine to alpha-methylstyrene of 1:1.6 and a total flow rate of 100ml/min, the alpha-methylstyrene containing 30ppm of p-tert-butylcatechol. The reaction temperature is 160 ℃, the adopted reaction solvent is o-dichlorobenzene, the reaction time is 30 minutes, and the 4,4' -di (phenylisopropyl) diphenylamine is finally obtained, and the yield is 89%.

Example 4

The difference from example 1 is that the two liquids were injected into the microchannel reactor at a molar diphenylamine to alpha-methylstyrene ratio of 1:2.0, with a total flow rate of 90 ml/min. The reaction solution A was not heated before the addition, the reaction temperature was controlled at 130 ℃ by a microchannel reactor using 400ml of o-dichlorobenzene as a solvent, and the reaction time was 40 minutes, to finally obtain 4,4' -bis (phenylisopropyl) diphenylamine in a yield of 90%.

Example 5

The difference from example 1 is that the amount of alpha-methylstyrene used is 177.0g (1.50mol), the molar ratio of diphenylamine to alpha-methylstyrene is 1:1.5, the total flow rate is 60ml/min, and the reaction time is 70 minutes, to finally obtain 4,4' -bis (phenylisopropyl) diphenylamine in a yield of 82%.

Example 6

The difference from example 1 is that the reaction solution at a total flow rate of 50mL/min (molar ratio of diphenylamine to alpha-methylstyrene is 1:2.0) was allowed to co-reside at 120 ℃ for 50min and then flowed out of the microchannel reactor, wherein the alpha-methylstyrene contained 60ppm of 2, 6-dinitro-p-cresol. 4,4' -bis (phenylisopropyl) diphenylamine was obtained in a yield of 92%.

Example 7

The difference from example 1 is that the amount of alpha-methylstyrene used is 295.0g (2.50mol), and the two liquids are injected into the microchannel reactor at a molar ratio of diphenylamine to alpha-methylstyrene of 1:2.5 and a total flow rate of 80mL/min, at a reaction temperature of 100 ℃ for 40 minutes, to finally obtain 4,4' -bis (phenylisopropyl) diphenylamine in a yield of 90%.

Example 8

The difference from example 1 is that 13.6g of activated clay was used as the catalyst, and the particle size of the activated clay was controlled to be 800 mesh or larger by sieving the activated clay before the reaction. Stirring and heating to 140 ℃, then uniformly dispersing the mixture in the reaction liquid A, injecting the two liquids into a microchannel reactor at a flow rate of which the molar ratio of diphenylamine to alpha-methylstyrene is 1:2, and reacting for 35 minutes to finally obtain the 4,4' -bis (phenylisopropyl) diphenylamine, wherein the yield is 89%.

The purity of 4,4' -bis (phenylisopropyl) diphenylamine obtained in comparative example and examples 1-8 was 99%.

The preparation method of the 4,4' -bis (phenylisopropyl) diphenylamine provided by the invention realizes the following advantages:

(1) the auto-polymerization of alpha-methyl styrene is avoided, the reaction material ratio can be accurately controlled, the usage amount of the alpha-methyl styrene is reduced, and the unit consumption is reduced;

(2) by controlling the proportion of the reaction raw materials and feeding the reaction raw materials independently, the self-polymerization of the alpha-methyl styrene is avoided, the reaction temperature is accurately controlled, and the reaction safety is improved;

(3) the reaction time is greatly shortened, and the energy consumption is low;

(4) nitrogen protection is not needed in the reaction process, so that the reaction cost is saved;

(5) can flexibly regulate and control the production scale according to the market demand, and is suitable for industrial production.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.