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Method for circularly preparing 3-bromine-4-hydroxybenzaldehyde

A technology of hydroxybenzaldehyde and p-hydroxybenzaldehyde, which is applied in the field of cyclic preparation of 3-bromo-4-hydroxybenzaldehyde, can solve the problems of inconvenient solvent recovery, low solvent recovery rate, and large solvent consumption, and achieve easy reaction conditions The effect of simple control and production process and low equipment requirements

Inactive Publication Date: 2017-11-24
BIJIA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main defect of this technique is: (1) solvent consumption is big
Furthermore CHCl 3 The boiling point is 61.2°C, and the low solvent recovery rate under reduced pressure is a matter of course
According to its recovery rate of 80%, the production of 17.1g3-bromo-4-hydroxybenzaldehyde needs to consume CHCl 3 As much as 70mL, solvent consumption is high
(2) Solvent recovery is inconvenient
These drawbacks limit the industrial application of this method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 3

[0023] The cyclic preparation method of the present embodiment 3-bromo-4-hydroxybenzaldehyde is carried out in the following steps:

[0024] 1. Place the 1L four-necked flask equipped with a stirrer, a reflux condenser (into the reflux condenser with cooling water at 5°C), a thermometer and a dropping funnel in a constant temperature water bath, add 12.2g of p-Hydroxybenzaldehyde and 238.76g of chloroform, stirred and dissolved at 40°C, then 19.18g of bromine was miscible in 23.9g of chloroform, slowly dropped into the bromination reactor within 0.8h, and stirred at 40°C under a negative pressure of 720mmHg 2h, stirring at 20°C for 2h to carry out the bromination reaction, and absorb the hydrogen bromide produced by the bromination reaction through three series-connected water absorbers;

[0025] 2. After the bromination reaction is completed, all the aqueous solutions in the three water absorbers are transferred to the bromination reactor, and NaOH solution is added to adjust...

Embodiment 2

[0032] The cyclic preparation method of the present embodiment 3-bromo-4-hydroxybenzaldehyde is carried out in the following steps:

[0033] 1. Place a 1L four-neck flask equipped with a stirrer, a reflux condenser (cooling water at 5°C in the reflux condenser), a thermometer and a dropping funnel in a constant temperature water bath, add 12.2g of p-hydroxybenzaldehyde, 119.4g of chloroform and 153.8g of carbon tetrachloride were stirred and dissolved at 40°C, then 19.2g of bromine was miscibly dissolved in 16g of chloroform and 7.7g of carbon tetrachloride, and slowly dropped into the bromination reactor within 1 hour In the process, under the negative pressure of 730mmHg, stir at 40°C for 2h, and stir at 24°C for 2h to carry out the bromination reaction, and absorb the hydrogen bromide produced by the bromination reaction through three series-connected water absorbers;

[0034] 2. After the bromination reaction is completed, transfer all the aqueous solutions in the three wa...

Embodiment 4

[0051] The cyclic preparation method of the present embodiment 3-bromo-4-hydroxybenzaldehyde is carried out in the following steps:

[0052] 1. Place a 1L four-neck flask equipped with a stirrer, a reflux condenser (cooling water at 5°C into the reflux condenser), a thermometer and a dropping funnel in a constant temperature water bath, add 36.7g of p-hydroxybenzaldehyde, 232.2g of ethyl acetate, stirred and dissolved at 40°C, then 57.6g of bromine was miscibly dissolved in 37.6g of ethyl acetate, slowly dropped into the bromination reactor within 0.5h, under the state of 720mmHg negative pressure, at 40°C Stir for 2h, stir at 22°C, carry out the bromination reaction for 2h, and absorb the hydrogen bromide produced by the bromination reaction through three series-connected water absorbers;

[0053] 2. After the bromination reaction is completed, transfer all the aqueous solutions in the three water absorbers to the bromination reactor, and add Na 2 CO 3 The pH value of the s...

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Abstract

The invention relates to a method for circularly preparing 3-bromine-4-hydroxybenzaldehyde. The preparation method comprises three processes of bromination reaction, solvent recovery and crystallization separating; in the invention, p-hydroxy benzaldehyde and bromine are subjected to a bromination reaction in a solvent, the solvent is recovered, and finally crystallization separating is carried out to obtain the product. The preparation method has the advantages of simple production process, easy control of reaction condition, and low equipment requirement; a byproduct bromide during the preparation process can be completely recovered to bromine for recycling, the mother liquor waste water in a reaction process can be fully and comprehensively used, and the disadvantages of large solvent consumption and high cost in the prior art can be overcome; in addition, the secondary waste water containing methyl chloride generated by solvent recovery through underpressure distillation by a washing technology in the prior art can be eliminated, the green production is realized, and method is easy for large-scale popularization and application.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a cyclic preparation method of 3-bromo-4-hydroxybenzaldehyde. Background technique [0002] 3-Bromo-4-hydroxybenzaldehyde is a fine chemical intermediate, which can be used as a raw material to synthesize methyl vanillin and other spices. It is also used in chemical industry, food processing and other fields, and it also has the ability to inhibit microbial growth. Features. [0003] At present, the more advanced preparation method for preparing 3-bromo-4-hydroxybenzaldehyde is to use p-hydroxybenzaldehyde as raw material through bromination reaction. The "Synthesis of 3-Bromo-4-Hydroxybenzaldehyde" published in the second issue of "Jihua Science and Technology" in 1994 and the 52nd issue of "Chemical Engineer" "Research on the New Process of Synthesizing Vanillin" introduced this process. . From the above-mentioned documents, it can be known that the main steps of the ...

Claims

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Application Information

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IPC IPC(8): C07C45/63C07C45/78C07C47/565
CPCC07C45/63C07C45/78C07C47/565
Inventor 毕佳
Owner BIJIA
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