Production process of phthalic dicarboxaldehyde

Abstract

The invention relates to the technical field of compound production, in particular to a production process of o-phthalaldehyde, which comprises the following steps: putting 1200kg of o-xylene into a clean chlorination kettle; heating the chlorination kettle to 90 DEG C by steam, then closing a steam valve, naturally heating to 100 + / -2 DEG C, and stabilizing for 10 minutes; the water bath temperature of the chlorine vaporizer is controlled to be 45 + / -5 DEG C, then the steel cylinder is slowly opened, chlorine is introduced into the chlorination kettle, and the chlorination temperature does not exceed 200 DEG C; closing the valve of the liquid chlorine steel cylinder, cooling the material in the chlorination kettle to 60 DEG C, discharging, then cooling to 0 DEG C, centrifuging, and drying to obtain a chlorinated product; adding water into a reaction kettle, and adding hydrochloric acid, the chlorination product and a catalyst under a stirring condition; heating to reflux, and carrying out reflux and heat preservation for 12 hours; after the reaction is finished, cooling water is started for cooling, stirring is stopped, standing is performed for 10 minutes, then lower-layer leftovers are separated and removed, and the leftovers are completely separated and removed by clicking for several times; and extracting, desolventizing, crystallizing, centrifuging and drying to obtain a finished product of o-phthalaldehyde.

Description

Technical Field

[0001] The invention relates to the technical field of compound production, in particular to a production process of o-phthalaldehyde. Background Art

[0002] O-phthalaldehyde is an important pharmaceutical chemical intermediate, which is widely used in analytical testing, sterilization and disinfection, and drug synthesis. For example, in analytical testing, o-phthalaldehyde can be used for the determination of histamine and alkaloids by fluorescence meter, and is also often used in amino acid analysis; in sterilization, o-phthalaldehyde-based disinfectants are often stable, have little odor, and have little irritation to human eye and nasal mucosa. They have excellent sterilization effects and good compatibility with most materials. These characteristics are significantly better than glutaraldehyde disinfectants, so they are widely favored by consumers; in the field of drug synthesis, o-phthalaldehyde can be used in the synthesis of antihypertensive drug lacidipine.

[0003] At present, there are many methods for synthesizing o-phthalaldehyde, mainly including: o-xylene halogenation and hydrolysis, o-phthalic alcohol direct oxidation, 1,3-dihydroisobenzofuran oxidation, naphthalene ozonation and hydrogenation, etc. The reagents generally used for direct oxidation of o-phthalic alcohol are relatively expensive, and when cheap nitric acid is used as an oxidant, there are many side reactions, resulting in unsatisfactory yields; 1,3-dihydroisobenzofuran oxidation and naphthalene ozonation and hydrogenation have the disadvantages of high production cost, complex process, and high equipment requirements, making it difficult to achieve industrial production. At present, the process suitable for industrial production is mainly o-xylene halogenation and hydrolysis. This method uses cheap o-xylene as the starting material, and after chlorination or bromination, it is hydrolyzed to obtain o-xylaldehyde. The bromination method requires the use of bromine, which is costly. Therefore, the ideal method is to use chlorine instead of bromine to chlorinate o-xylene. However, under high temperature conditions, the conversion rate is low because chlorine cannot be fully utilized. To ensure the same conversion rate, the amount of chlorine used needs to be greatly increased, which not only increases costs but also puts pressure on environmental protection. Summary of the invention

[0004] Based on the above purpose, the present invention provides a production process of o-phthalaldehyde.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A production process of o-phthalaldehyde, characterized in that it comprises the following steps:

[0007] Step 1: Add 1200 kg of o-xylene into a clean chlorination kettle;

[0008] Step 2, heating the chlorination kettle: steam heat the chlorination kettle to 90°C, then close the steam valve, naturally heat up to 100±2°C, and stabilize for 10 minutes;

[0009] Step 3: Pass chlorine: The water bath temperature of the chlorine vaporizer is controlled at 45±5°C, then slowly open the cylinder and pass chlorine into the chlorination kettle. The chlorination temperature does not exceed 200°C;

[0010] Step 4, discharging: close the valve of the liquid chlorine cylinder, cool the material in the chlorination kettle to 60°C and discharge, then centrifuge when cooled to 0°C, and dry to obtain tetrachloro-o-xylene;

[0011] Step 5, mixing; add water to the reactor, add hydrochloric acid, chlorination product and catalyst under stirring; heat to reflux, and keep reflux for 12 hours; after the reaction is completed, turn on the cooling water to cool down and stop stirring to stand for 10 minutes, then remove the bottom layer of scraps, click several times to ensure that the scraps are completely removed;

[0012] Step 6, extraction; start stirring, cool to about 40°C, slowly add 2 barrels of dichloroethane through the high-level tank, stir and extract for 1 hour, then stop stirring, let it stand for 20 minutes, transfer the lower organic layer to the desolventizing kettle, add 2 barrels of dichloroethane to the aqueous phase for secondary extraction, repeat the previous operation, and transfer the secondary extract to the high-level tank for application;

[0013] Step seven, desolventizing; desolventizing under negative pressure until the temperature reaches about 65°C, then stop desolventizing, add toluene to dissolve, crystallize, then centrifuge at 0°C, and dry to obtain the finished product of o-phthalaldehyde.

[0014] In the present invention, o-xylene is chlorinated to obtain tetrachloro-o-xylene, and tetrachloro-o-xylene is hydrolyzed to obtain o-phthalaldehyde, and the chemical formula is as follows:

[0015]

[0016] The beneficial effects of the present invention are: the method for synthesizing o-phthalaldehyde has low cost, simple equipment requirements, simple operation and relatively ideal yield. The method is characterized in that o-xylene is used as a starting material, reacts with chlorine gas under heating conditions to chlorinate, then the chlorinated product is mixed with hydrochloric acid and a catalyst for reaction, then extracted with dichloroethane, and finally deoxidized with toluene to synthesize o-phthalaldehyde with relatively ideal yield and purity. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1

[0019] A production process of o-phthalaldehyde, characterized in that it comprises the following steps:

[0020] Step 1: Add 1200 kg of o-xylene into a clean chlorination kettle;

[0021] Step 2, heating the chlorination kettle: steam heat the chlorination kettle to 90°C, then close the steam valve, naturally heat up to 100°C, and stabilize for 10 minutes;

[0022] Step 3: Pass chlorine: The water bath temperature of the chlorine vaporizer is controlled at 45°C, then slowly open the cylinder and pass chlorine into the chlorination kettle. The chlorination temperature does not exceed 200°C;

[0023] Step 4, discharging: close the valve of the liquid chlorine cylinder, cool the material in the chlorination kettle to 60°C and discharge, then centrifuge when cooled to 0°C, and dry to obtain tetrachloro-o-xylene;

[0024] Step 5, mixing; add water to the reactor, add hydrochloric acid, chlorination product and catalyst under stirring; heat to reflux, and keep reflux for 12 hours; after the reaction is completed, turn on the cooling water to cool down and stop stirring to stand for 10 minutes, then remove the bottom layer of scraps, click several times to ensure that the scraps are completely removed;

[0025] Step 6, extraction; start stirring, cool to about 40°C, slowly add 2 barrels of dichloroethane through the high-level tank, stir and extract for 1 hour, then stop stirring, let it stand for 20 minutes, transfer the lower organic layer to the desolventizing kettle, add 2 barrels of dichloroethane to the aqueous phase for secondary extraction, repeat the previous operation, and transfer the secondary extract to the high-level tank for application;

[0026] Step seven, desolventizing; desolventizing under negative pressure until the temperature reaches about 65°C, then stop desolventizing, add toluene to dissolve, crystallize, then centrifuge at 0°C, and dry to obtain the finished product of o-phthalaldehyde.

[0027] Example 2

[0028] A production process of o-phthalaldehyde, characterized in that it comprises the following steps:

[0029] Step 1: Add 1200 kg of o-xylene into a clean chlorination kettle;

[0030] Step 2, heating the chlorination kettle: steam heat the chlorination kettle to 90°C, then close the steam valve, naturally heat up to 102°C, and stabilize for 10 minutes;

[0031] Step 3: Pass chlorine: The water bath temperature of the chlorine vaporizer is controlled at 50°C, then slowly open the cylinder and pass chlorine into the chlorination kettle. The chlorination temperature does not exceed 200°C;

[0032] Step 4, discharging: close the valve of the liquid chlorine cylinder, cool the material in the chlorination kettle to 60°C and discharge, then centrifuge when cooled to 0°C, and dry to obtain tetrachloro-o-xylene;

[0033] Step 5, mixing; add water to the reactor, add hydrochloric acid, chlorination product and catalyst under stirring; heat to reflux, and keep reflux for 12 hours; after the reaction is completed, turn on the cooling water to cool down and stop stirring to stand for 10 minutes, then remove the bottom layer of scraps, click several times to ensure that the scraps are completely removed;

[0034] Step 6, extraction; start stirring, cool to about 40°C, slowly add 2 barrels of dichloroethane through the high-level tank, stir and extract for 1 hour, then stop stirring, let it stand for 20 minutes, transfer the lower organic layer to the desolventizing kettle, add 2 barrels of dichloroethane to the aqueous phase for secondary extraction, repeat the previous operation, and transfer the secondary extract to the high-level tank for application;

[0035] Step seven, desolventizing; desolventizing under negative pressure until the temperature reaches about 65°C, then stop desolventizing, add toluene to dissolve, crystallize, then centrifuge at 0°C, and dry to obtain the finished product of o-phthalaldehyde.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A production process of o-phthalaldehyde, characterized in that: The steps include: Step 1: Add o-xylene into a clean chlorination kettle; Step 2, heating the chlorination kettle; after the steam heats the chlorination kettle to a certain temperature, close the steam valve, naturally heat up to a certain temperature, and stabilize for 10 minutes; Step 3: Pass chlorine: The water bath temperature of the chlorine vaporizer is controlled at 45±5°C, then slowly open the cylinder and pass chlorine into the chlorination kettle; Step 4, discharging: close the valve of the liquid chlorine cylinder, discharge the material in the chlorination kettle after cooling, then centrifuge when the temperature drops to 0°C, and dry to obtain tetrachloro-o-xylene; Step 5: Mixing: adding water into the reaction kettle, and adding hydrochloric acid, chlorination product and catalyst under stirring; Raise the temperature to reflux and keep reflux for 12 hours; After the reaction is over, turn on the cooling water to cool down and stop stirring. Let it stand for 10 minutes and then remove the bottom layer of scraps. Click it several times to ensure that the scraps are completely removed. Step 6, extraction; start stirring, cool to about 40°C, slowly add 2 barrels of dichloroethane through the high-level tank, stir and extract for 1 hour, then stop stirring, let it stand for 20 minutes, transfer the lower organic layer to the desolventizing kettle, add 2 barrels of dichloroethane to the aqueous phase for secondary extraction, repeat the previous operation, and transfer the secondary extract to the high-level tank for application; Step seven, desolventizing; desolventizing under negative pressure until the temperature reaches about 65°C, then stop desolventizing, add toluene to dissolve, crystallize, then centrifuge at 0°C, and dry to obtain the finished product of o-phthalaldehyde.

2. A production process for o-phthalaldehyde according to claim 1, characterized in that: In step one, the chlorination kettle is heated to 90°C with steam.

3. A production process for o-phthalaldehyde according to claim 1, characterized in that: In step 1, the temperature is naturally raised to 100±2°C.

4. A production process for o-phthalaldehyde according to claim 1, characterized in that: In step 3, the chlorination temperature does not exceed 200°C.

5. A production process for o-phthalaldehyde according to claim 1, characterized in that: In step 4, the material in the chlorination kettle is cooled to 60°C and discharged.

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