Method for preparing p-hydroxybenzene formaldehyde by diazo salt hydrolysis of p-aminobenzaldehyde

A technology of p-hydroxybenzaldehyde and p-aminobenzaldehyde, which is applied in the field of p-hydroxybenzaldehyde preparation, can solve problems such as unstable product quality, difficult process control, and low production efficiency, and achieve rapid temperature rise, reduced back-mixing, and improved The effect on product yield

Active Publication Date: 2012-07-25
ZHONGBEI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, the production time is longer, the by-products are many, the product yield is low (only about 55%), the process is difficult to control, and the product quality is unstable
[0004] In order to increase the yield of phenol by hydrolysis of diazonium salt, Hao Yanxia (Journal of Fire and Explosives, 2002 (1): 64~66), Zhang Zhenming (Chemical Journal, 2004 (18) 6: 48~49) etc. The process has been studied to optimize the process. The main methods are phase transfer method, steam distillation method, etc. Although the yield of hydrolyzed product phenol has been improved through process improvement, the process of product separation and solvent recovery has been added. The problems of low production efficiency and high energy consumption in the instant kettle method have not been completely resolved

Method used

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  • Method for preparing p-hydroxybenzene formaldehyde by diazo salt hydrolysis of p-aminobenzaldehyde
  • Method for preparing p-hydroxybenzene formaldehyde by diazo salt hydrolysis of p-aminobenzaldehyde
  • Method for preparing p-hydroxybenzene formaldehyde by diazo salt hydrolysis of p-aminobenzaldehyde

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Put the diazonium salt solution of p-aminobenzaldehyde into the head tank 4 with the pump 2, open the hot air intake valve 8, heat the rotary packed bed 11 to 65°C, and adjust the rotating speed of the rotary packed bed 11 to 600r / min at the same time , open the discharge valve 5 of the head tank 4 to a certain opening, and adjust the flow rate of the raw material diazonium salt into the rotary packed bed 11 to be 1.0m 3 / h, the material enters the deflector tower 12 to continue post-reaction after mixing and preliminary reaction in the rotating packed bed 11, and the total residence time of the reaction materials passing through the rotating packed bed 11 and the deflector tower 12 is 140s. After the reaction is completed, the reaction solution enters the filter I13 equipped with activated carbon from the liquid outlet of the deflector plate tower 12 to filter out the oily by-product while it is hot, and then enters the tube condenser 14 to rapidly cool the gained hydro...

Embodiment 2

[0045] Use the pump 2 to pump the diazonium salt solution of the raw material p-aminobenzaldehyde into the head tank 4, open the hot air intake valve 8, heat the rotary packed bed 11 to 68°C, and simultaneously adjust the rotating speed of the rotary packed bed 11 to 600r / h min, open the discharge valve 5 of the head tank 4, and adjust the flow rate of the raw material diazonium salt into the rotary packed bed 11 to be 0.5m 3 / h, the material enters the deflector tower 12 to continue post-reaction after mixing and preliminary reaction in the rotating packed bed 11, and the total residence time of the reaction materials passing through the rotating packed bed 11 and the deflector tower 12 is 180s. After the reaction is completed, the reaction liquid enters the filter I13 equipped with glass wool from the outlet of the deflector plate tower 12 to filter while it is hot, and then enters the tube condenser 14 to rapidly cool the gained hydrolyzate to room temperature. After cooling...

Embodiment 3

[0047] Use the pump 2 to pump the diazonium salt solution of the raw material p-aminobenzaldehyde stored in the diazo liquid storage tank into the head tank 4, open the hot air intake valve 8, heat the rotating packed bed 11 to 72 ° C, and rotate the packing The rotating speed of bed 11 is adjusted to 800r / min, the discharge valve 5 of head tank 4 is opened, and the flow rate of raw material diazonium salt entering rotary packed bed 11 is adjusted to 0.5m 3 / h, the material enters the deflector tower 12 to continue post-reaction after mixing and preliminary reaction in the rotating packed bed 11, and the total residence time of the reaction materials passing through the rotating packed bed 11 and the deflector tower 12 is 180s. After the reaction was completed, the reaction liquid entered the filter I13 equipped with gac from the liquid outlet of the deflector plate tower 12 to filter while it was hot, and then entered the tube condenser 14 to cool the gained hydrolyzate to roo...

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Abstract

The invention belongs to the technical field of preparing parahydroxyben-zaldehyde, and more particularly relates to a method for preparing parahydroxyben-zaldehyde by hydrolyzing diazo salt of para aminotenzaldehyde and a device thereof. The invention solves the problems of low efficiency and high energy consumption in the existing method for preparing the parahydroxyben-zaldehyde. The method comprises the steps: reactant is thrown into a rotary packed bed to be heated and then enters a diversion plate type tower, and sent out to be filtered, condensed and filtered again. The device comprises the rotary packed bed and the diversion plate type tower, wherein, a liquid inlet of the rotary packed bed is connected with a liquid storage tank of diazonium, an air inlet is connected with a thermal medium generator, and a liquid outlet is connected with a liquid inlet of the diversion plate type tower; a liquid outlet of the diversion plate type tower is connected with a filter I which is connected with a condenser. The invention has the beneficial effects of easily controlled process, stable operation, uniform product quality, small volume of the device, convenient installation and maintenance and short startup and shutdown time.

Description

technical field [0001] The invention belongs to the technical field of p-hydroxybenzaldehyde preparation, and in particular relates to a method and a device for preparing p-hydroxybenzaldehyde by hydrolysis of diazonium salt of p-aminobenzaldehyde. Background technique [0002] p-Hydroxybenzaldehyde is called PHB for short. The appearance of pure product is colorless or light yellow needle-like crystal with aromatic smell. Its melting point is 116.4°C-118°C (sublimation). Soluble in water and benzene. p-Hydroxybenzaldehyde is an important fine chemical intermediate, widely used in medicine, pesticide, fragrance, cosmetics, liquid crystal, electroplating and other fields. In recent years, with the rapid development of my country's pesticide, pharmaceutical and spice industries, the domestic demand for p-hydroxybenzaldehyde is on the rise. However, domestic production capacity cannot meet the demand, production costs are high, and product quality is low. Therefore, , my count...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C47/565C07C45/64
Inventor 张巧玲申红艳焦纬洲
Owner ZHONGBEI UNIV
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