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Method for preparing 3,5-dibromine-4-hydroxy benzaldehyde

A technology of hydroxybenzaldehyde and o-dichlorobenzene, which is applied in 3 fields, can solve the problems of high production cost and rising price of p-hydroxybenzaldehyde, and achieve the effects of increasing yield, reducing water content and improving utilization rate

Inactive Publication Date: 2008-08-27
SHANDONG MORIS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, with the rapid development of industries such as medicine, pesticides, and spices, the domestic demand for p-hydroxybenzaldehyde has increased significantly, while the domestic market has a large gap and relies heavily on imports; the price of p-hydroxybenzaldehyde continues to rise, resulting in production high cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Add 200g (1.85mol) of p-cresol and 92.5g (0.74mol) of o-dichlorobenzene into a 1000ml bromination reactor respectively, stir to dissolve fully, control the temperature at 40°C, and control the vacuum at ≤0Mpa, drop Add Br 2 563g (3.52mol), bromination reaction 5h, collect the HBr gas produced in the reaction process simultaneously, after the reaction finishes, keep warm for 1h;

[0025] (2) After the heat preservation is completed, slowly raise the temperature to 140°C, control the vacuum at ≤0Mpa, and add 560g (3.5mol) Br dropwise 2 , bromination reaction for 6 hours, while collecting the HBr gas generated during the reaction, after the reaction, keep it warm for 2 hours, and naturally cool down to 125 ° C to obtain bromination material liquid for future use;

[0026] (3) While the bromination material liquid is cooling, in the 2000ml hydrolysis reactor, adding concentration is 15% HBr acid 700g (1.30mol), reclaims o-dichlorobenzene;

[0027] (4) Then transfer th...

Embodiment 2

[0031] (1) Add 250g (2.31mol) of p-cresol and 100g (0.8mol) of o-dichlorobenzene to a 1000ml bromination reactor respectively, stir to dissolve fully, control the temperature at 38°C, and control the vacuum at ≤0Mpa, add dropwise Br 2 720g (4.5mol), bromination reaction 5h, while collecting the HBr gas generated in the reaction process, after the reaction, keep warm for 1h;

[0032] (2) After the heat preservation is completed, the temperature is slowly raised to 148°C, the vacuum is controlled at ≤0Mpa, and 715g (4.47mol) of Br is added dropwise 2 , the bromination reaction was 6.5 hours, and the HBr gas generated during the reaction was collected at the same time. After the reaction, the temperature was kept for 2 hours, and the temperature was naturally lowered to 125 ° C to obtain the bromination liquid, which was set aside;

[0033] (3) While the bromination material liquid is cooling, in the 2000ml hydrolysis reactor, adding concentration is 15% HBr acid 750g (1.39mol),...

Embodiment 3

[0038] (1) Into a 1000ml bromination reactor, add 210g (1.94mol) of p-cresol and 92.5g (0.74mol) of o-dichlorobenzene respectively, stir to dissolve fully, control the temperature at 42°C, and control the vacuum at ≤0Mpa, drop Add Br 2 600g (3.75mol), bromination reaction 5h, while collecting the HBr gas generated in the reaction process, after the reaction, keep warm for 1h;

[0039] (2) After the heat preservation is completed, slowly raise the temperature to 155°C, control the vacuum at ≤0Mpa, and add 600g (3.75mol) Br dropwise 2 , bromination reaction for 7 hours, and the HBr gas generated during the reaction was collected at the same time. After the reaction was completed, it was kept for 2 hours, and the temperature was naturally lowered to 125 ° C to obtain a bromination liquid, which was set aside;

[0040] (3) While the bromination feed liquid is cooling, add 18% HBr acid 700g (1.56mol) in the 2000ml hydrolysis reactor to reclaim o-dichlorobenzene;

[0041] (4) Then...

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Abstract

The invention provides a preparation method of 3, 5-dibromo-4-hydroxy benzaldehyde, which uses p-cresol and o-dichlorobenzen as raw materials, processes low-temperature bromination at 32-42DEG C, high-temperature bromination at 145-168DEG C, hydrolysis, dehydration and drying to synthesize 3, 5-dibromo-4-hydroxy benzaldehyde. The inventive method has clear mechanism, simple operation, high product yield and reduced water content, while the HBr gas generated in preparation can be recovered to be reused, thereby reducing production cost, saving energy and protecting environment. The invention is suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of 3,5-dibromo-4-hydroxybenzaldehyde, which belongs to the field of marine fine chemicals. Background technique [0002] 3,5-Dibromo-4-hydroxybenzaldehyde, also known as dibromoaldehyde, is an important pharmaceutical and pesticide intermediate. Dibromoaldehyde is the main raw material for the production of 3,4,5-trimethoxybenzaldehyde and bromoxynil. 3,4,5-trimethoxybenzaldehyde (TMB) is used in the synthesis of antibacterial drugs and sulfa synergist Bromoxynil, an intermediate of benzylaminopyridine (TMP), is widely used as a contact herbicide for selective post-emergence stem and leaf treatments. [0003] The Journal of Qingdao Institute of Chemical Technology, No. 2, 2002, pages 36-38, Cao Wei, Department of Applied Chemistry, Qingdao Institute of Chemical Technology, etc., reported the synthesis process of 3,4,5-trimethoxybenzaldehyde, which mentioned the use of p-hydroxybenzaldehyde and bromine Gen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/565C07C45/42C07C45/00
Inventor 杨树仁黄伟李德旺宋前进郝建港丁瑞林徐永生
Owner SHANDONG MORIS TECH
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