Method for preparing hydrazinobenzene in continuous micro-channel reactor

Abstract

The invention relates to a method for preparing highly pure hydrazinobenzene by using continuous flow micro-channel reactor. The method concretely comprises the following steps: preparing aniline hydrochloride from hydrochloric acid and aniline, respectively pumping the aniline hydrochloride and a sodium nitrite solution into the micro-channel reactor by two metering pumps to obtain a diazo salt solution, reducing the obtained reaction solution, carrying out acid separation on the reduced solution, filtering the obtained solution, neutralizing the filtered solution, and distilling the neutralized solution to obtain the highly pure hydrazinobenzene. The diazotization process is a strong exothermic reaction, and the generated diazo salt easily decomposes after standing at a high temperature for a long time, and generates toxic gases which pollute environment and even blast. The mixing effect of the heart-shaped micro-channel reactor is far better than the mass transfer effect generated by stirring, so the aniline conversion rate can reach 99%, the mixing mass transfer effect is good, and heat conduction is fast to avoid local overheating phenomenon; and the reaction can be carried out at constant temperature conditions, so the temperature runaway blast danger of general reactors is eliminated, and the safety is improved.

Description

Technical field

[0001] The present invention relates to the synthesis of phenylhydrazine. The specific content includes the use of a "heart" type microchannel reactor (Corning's high-throughput microchannel reactor) to diazotize aniline to prepare phenylhydrazine, which belongs to the field of fine chemicals. A novel method for preparing phenylhydrazine. Background technique

[0002] Phenylhydrazine is an important intermediate of dyes, medicines, and pesticides. It can be used as an antidepressant for the treatment of polycythemia. It can be used to synthesize saccharine, phenylhydrazone, alkyl indole, and 1H-indazole-3-carboxylic acid. , Drugs clonidamine, edaravone, pyrazole derivatives, pyrazolone derivatives, tryptamine derivatives pyridazinone thiadiazoles and pyridazin pyrazolone derivatives, etc., can also be combined with metal Form a complex.

[0003] The synthesis process of phenylhydrazine mainly adopts aniline diazotization, reduction, hydrolysis, and distillation pr...

Examples

Embodiment 1

[0030] Device: Coring heart-shaped microchannel reactor, 6 plates are selected for the reaction module, and the raw material feeding method is referred to image 3 Confirm that the heat exchange medium is heat transfer oil.

[0031] Aniline hydrochloride configuration: At room temperature, add 310 ml of 30% hydrochloric acid (3.0 mol) and 200 mL of water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0032] Sodium nitrite solution configuration: 64 g (1.0 mol) sodium nitrite and 300 mL of water are used to make a 40% sodium nitrite solution.

[0033] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 5°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump with a flow rate of 20 mL / min ,Pour 40% sodium nitrite solution into the reactor through a...

Embodiment 2

[0038] Aniline hydrochloride configuration: at room temperature, add 237 ml 30% hydrochloric acid (2.3 mol) and 200 mL water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0039] Sodium nitrite solution configuration: 64g (1.0 mol) of sodium nitrite and 300 mL of water are mixed into a 40% sodium nitrite solution.

[0040] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 0°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump, with a flow rate of 20 mL / min , The 40% sodium nitrite solution was pumped into the reactor through a metering pump, the flow rate was controlled at 44 mL / min, the materials were reacted in the microchannel reactor, the reaction residence time was 28 s, the reaction pressure was 0.2 MPa, and the diazonium liquid The r...

Embodiment 3

[0045] Aniline hydrochloride configuration: at room temperature, add 330 ml 30% hydrochloric acid (3.2 mol) and 200 mL water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0046] Sodium nitrite solution configuration: 64 g (1.0mol) sodium nitrite and 300 mL of water are mixed into a 40% sodium nitrite solution.

[0047] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 10°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump, with a flow rate of 20 mL / min ,Pour 40% sodium nitrite solution into the reactor through a metering pump. The flow rate is controlled at 48 mL / min. The materials react in the microchannel reactor. The reaction residence time is 26 s, the reaction pressure is 0.2 MPa, and the diazonium liquid The reactor flows continuous...

Technical field

[0001] The present invention relates to the synthesis of phenylhydrazine. The specific content includes the use of a "heart" type microchannel reactor (Corning's high-throughput microchannel reactor) to diazotize aniline to prepare phenylhydrazine, which belongs to the field of fine chemicals. A novel method for preparing phenylhydrazine. Background technique

[0002] Phenylhydrazine is an important intermediate of dyes, medicines, and pesticides. It can be used as an antidepressant for the treatment of polycythemia. It can be used to synthesize saccharine, phenylhydrazone, alkyl indole, and 1H-indazole-3-carboxylic acid. , Drugs clonidamine, edaravone, pyrazole derivatives, pyrazolone derivatives, tryptamine derivatives pyridazinone thiadiazoles and pyridazin pyrazolone derivatives, etc., can also be combined with metal Form a complex.

[0003] The synthesis process of phenylhydrazine mainly adopts aniline diazotization, reduction, hydrolysis, and distillation pr...

Examples

Embodiment 1

[0030] Device: Coring heart-shaped microchannel reactor, 6 plates are selected for the reaction module, and the raw material feeding method is referred to image 3 Confirm that the heat exchange medium is heat transfer oil.

[0031] Aniline hydrochloride configuration: At room temperature, add 310 ml of 30% hydrochloric acid (3.0 mol) and 200 mL of water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0032] Sodium nitrite solution configuration: 64 g (1.0 mol) sodium nitrite and 300 mL of water are used to make a 40% sodium nitrite solution.

[0033] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 5°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump with a flow rate of 20 mL / min ,Pour 40% sodium nitrite solution into the reactor through a...

Embodiment 2

[0038] Aniline hydrochloride configuration: at room temperature, add 237 ml 30% hydrochloric acid (2.3 mol) and 200 mL water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0039] Sodium nitrite solution configuration: 64g (1.0 mol) of sodium nitrite and 300 mL of water are mixed into a 40% sodium nitrite solution.

[0040] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 0°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump, with a flow rate of 20 mL / min , The 40% sodium nitrite solution was pumped into the reactor through a metering pump, the flow rate was controlled at 44 mL / min, the materials were reacted in the microchannel reactor, the reaction residence time was 28 s, the reaction pressure was 0.2 MPa, and the diazonium liquid The r...

Embodiment 3

[0045] Aniline hydrochloride configuration: at room temperature, add 330 ml 30% hydrochloric acid (3.2 mol) and 200 mL water into a 1000 mL three-necked flask, add 93 g (1.0 mol) of aniline dropwise within 30 minutes, and stir for 30 minutes after the addition , Formulated into aniline hydrochloride.

[0046] Sodium nitrite solution configuration: 64 g (1.0mol) sodium nitrite and 300 mL of water are mixed into a 40% sodium nitrite solution.

[0047] Diazotization: Use a circulator cooler to cool the reactor. Set the temperature of the reactor to 10°C. After the temperature stabilizes, pump the aniline hydrochloride solution into the reactor through a metering pump, with a flow rate of 20 mL / min ,Pour 40% sodium nitrite solution into the reactor through a metering pump. The flow rate is controlled at 48 mL / min. The materials react in the microchannel reactor. The reaction residence time is 26 s, the reaction pressure is 0.2 MPa, and the diazonium liquid The reactor flows continuous...

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