Preparation method of phthalimide compound

Abstract

The invention relates to the technical field of chemical preparation, and discloses a preparation method of a phthalimide compound, which comprises the following steps: S1, raw material mixing: sequentially adding phthalic anhydride, a primary amine compound, p-toluenesulfonic acid and phosphorus pentoxide into a reaction container with a stirring device and a temperature control module, and stirring for 1-2 hours; adding ethanol as a solvent, and carrying out a stirring reaction; s2, curing: cooling the reaction liquid to 20-25 DEG C, slowly adding deionized water into the reaction liquid while stirring, standing, and separating out a solid product; a traditional dehydrating agent is changed into a low-cost green dehydrating agent combination, so that the cost loss is reduced, the stimulation effect is reduced, the catalytic activity is equivalent to that of p-toluenesulfonic acid by adding a new sulfonic group functional polymer, but the problems of volatility of liquid acid and equipment corrosion are avoided, a low-toxicity and low-cost solvent of ethanol is added, the toxicity is reduced, and the environment-friendly dehydrating agent is prepared. The preparation is safer, the cost is lower, and the applicability is wider.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of chemical preparation, in particular to a preparation method of an o-phthalimide compound. BACKGROUND

[0002] The o-phthalimide compound is an important organic compound with industrial value, the imide group contained in the molecular structure of the o-phthalimide compound has good reactivity, and various functional compounds can be derived through hydrolysis, aminolysis and reduction, so that the o-phthalimide compound is widely applied in the fields of medicines, dyes, pesticides and polymer materials. There are various syntheses of the existing preparation method of the o-phthalimide compound, wherein the o-phthalimide compound is synthesized by using o-phthalic anhydride and primary amine compounds as raw materials, however, the existing method has the problems that the solvent-free melting reaction needs high energy consumption, and due to high temperature, the raw materials are prone to carbonization, the color of the product is deepened, and the difficulty of subsequent purification is increased, and the high-boiling-point polar solvent can reduce the reaction temperature, but the solvent needs to be recovered through distillation after the reaction, the operation is complicated, the energy consumption is significantly increased, and the method does not conform to the development trend of green chemical industry.

[0003] In view of the above problems, a preparation method of an o-phthalimide compound is provided. SUMMARY

[0004] The application aims to provide a preparation method of an o-phthalimide compound, which can efficiently remove water molecules, reduce the corrosiveness of organic acids and improve the recovery of the catalyst.

[0005] To achieve the above-mentioned purpose, the application provides the following technical scheme: a preparation method of an o-phthalimide compound, comprising the following steps: S1, raw material mixing, o-phthalic anhydride, primary amine compounds, p-toluenesulfonic acid and diaphosphorus pentoxide are sequentially added into a reaction container provided with a stirring device and a temperature control module, and then ethanol is added as a solvent to perform stirring reaction; S2, solidification, the reaction liquid is cooled to 20-25 DEG C, deionized water is slowly added thereto while stirring, and then the mixture is statically placed to precipitate solid products; S3, purification treatment, the precipitated solid products are filtered, washed with sodium bicarbonate aqueous solution and then washed with deionized water, and the washed solid products are dried in a vacuum drying box to obtain the o-phthalimide compound.

[0006] As a further description of the above technical solution: In step S1, the molar ratio of phthalic anhydride to primary amine compound is 1:1.1, the amount of p-toluenesulfonic acid added is 5% of the molar amount of phthalic anhydride, the amount of phosphorus pentoxide added is 1.5 times the molar amount of phthalic anhydride, and the mass ratio of ethanol to phthalic anhydride is 5:1.

[0007] As a further description of the above technical solution: In step S2, the volume ratio of deionized water to ethanol is 2.5:1.

[0008] As a further description of the above technical solution: In step S3, the drying environment is a temperature of 65-75℃ and a vacuum degree of 0.09-0.098MPa; the drying time is 3-5 hours.

[0009] As a further description of the above technical solution: the primary amine compound is selected from aliphatic primary amines or aromatic primary amines; the aliphatic primary amine is a straight-chain or branched alkyl primary amine with 1-8 carbon atoms, including at least one of methylamine, ethylamine, n-propylamine, isopropylamine, and n-butylamine; the aromatic primary amine is an aniline with an unsubstituted benzene ring or substituted by 1-2 methyl, methoxy, or fluorine atoms, including at least one of aniline, p-methylaniline, p-methoxyaniline, and o-fluoroaniline.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention provides a method for preparing phthalimide compounds. By replacing the traditional dehydrating agent with a low-cost, green dehydrating agent combination, the cost loss is reduced and the irritation effect is decreased. By adding a new sulfonic acid-functionalized polymer, the catalytic activity is comparable to that of p-toluenesulfonic acid, but without the volatility and equipment corrosion problems of liquid acid. The addition of ethanol, a low-toxicity and low-cost solvent, reduces toxicity, making the preparation safer, lower in cost, and more widely applicable. Detailed Implementation

[0011] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0012] To further understand the content of this invention, a detailed description of this invention is provided.

[0013] A method for preparing a phthalimide compound includes the following steps: S1. Raw materials are mixed. Phthalic anhydride, primary amine compounds, p-toluenesulfonic acid, and phosphorus pentoxide are added sequentially to a reaction vessel equipped with a stirring device and a temperature control module. Ethanol is then added as a solvent, and the mixture is stirred and reacted. The molar ratio of phthalic anhydride to primary amine compounds is 1:1.1. The amount of p-toluenesulfonic acid added is 5% of the molar amount of phthalic anhydride, and the amount of phosphorus pentoxide added is 1.5 times the molar amount of phthalic anhydride. The mass ratio of ethanol to phthalic anhydride is 5:1. The primary amine compounds are selected from aliphatic primary amines or aromatic primary amines. The aliphatic primary amines are straight-chain or branched alkyl primary amines with 1-8 carbon atoms, including at least one of methylamine, ethylamine, n-propylamine, isopropylamine, and n-butylamine. The aromatic primary amines are those with unsubstituted or 1-2-substituted carbon atoms on the benzene ring. Aniline selected from methyl, methoxy, or fluorine-substituted anilines, including at least one of aniline, p-methylaniline, p-methoxyaniline, and o-fluoroaniline; during stirring, the stirring rate is controlled at 250-350 r / min, and the reaction system is heated to 60-70°C at a heating rate of 4-8°C / min, and the reaction is maintained at this temperature for 2-3 hours.

[0014] S2. Curing: Cool the reaction solution to 20-25℃, slowly add deionized water while stirring, then let it stand to precipitate solid product. The volume ratio of deionized water to ethanol is 2.5:1. The stirring rate is 180-220 r / min. Stirring for 15-25 min and then letting it stand for 20-30 min will result in the best curing effect.

[0015] S3. Purification treatment: Filter the precipitated solid product, wash it with sodium bicarbonate aqueous solution, and then wash it with deionized water; place the washed solid product in a vacuum drying oven for drying to obtain phthalimide compounds. The drying environment is 65-75℃ and 0.09-0.098MPa; the drying time is 3-5 hours; the sodium bicarbonate aqueous solution can be washed 3-4 times to make the pH of the washing solution 6.8-7.2.

[0016] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a phthalimide compound, characterized in that: The method comprises the following steps: S1, raw material mixing, adding phthalic anhydride, primary amine compound, p-toluenesulfonic acid and phosphorus pentoxide into a reaction container with stirring device and temperature control module in sequence, then adding ethanol as solvent, and stirring and reacting; S2, solidification, cooling the reaction liquid to 20-25 DEG C, slowly adding deionized water into the reaction liquid, stirring while adding, and then standing to precipitate solid product; S3, purification treatment, filtering the precipitated solid product, washing with sodium bicarbonate aqueous solution, then washing with deionized water, and drying the washed solid product in vacuum drying oven to obtain phthalimide compound.

2. The method for preparing a phthalimide compound according to claim 1, characterized in that: In the step S1, the molar ratio of phthalic anhydride to primary amine compound is 1:1.1, the addition amount of p-toluenesulfonic acid is 5% of the molar amount of phthalic anhydride, the addition amount of phosphorus pentoxide is 1.5 times of the molar amount of phthalic anhydride, and the mass ratio of ethanol to phthalic anhydride is 5:

1.

3. The method for preparing a phthalimide compound according to claim 1, characterized in that: In the step S2, the volume ratio of deionized water to ethanol is 2.5:

1.

4. The method for preparing a phthalimide compound according to claim 1, characterized in that: In the step S3, the drying environment is 65-75 DEG C and the vacuum degree is 0.09-0.098 MPa; the drying time is 3-5 hours.

5. The method for preparing a phthalimide compound according to claim 1, characterized in that: The primary amine compound is selected from aliphatic primary amine or aromatic primary amine; the aliphatic primary amine is linear or branched alkyl primary amine with carbon atom number of 1-8, including at least one of methylamine, ethylamine, n-propylamine, isopropylamine and n-butylamine; the aromatic primary amine is aniline unsubstituted or substituted with 1-2 groups selected from methyl, methoxy and fluorine atom on benzene ring, including at least one of aniline, p-methyl aniline, p-methoxy aniline and o-fluoro aniline.