Method for continuously preparing vanillin and syringaldehyde

A technology for syringaldehyde and vanillin, which is applied in the field of continuous preparation of vanillin and syringaldehyde, can solve the problems of large quantity of three wastes, low yield, uneconomical, etc. Process flow, the effect of simplified operation

Inactive Publication Date: 2019-12-24
孔繁昇 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, it mainly comes from the oxidative degradation of lignin (CN10556608, CN102146025) and chemical synthesis ("Fine Petrochemical" in No. 3 in 1989); these all have the disadvantages of large amount of three wastes, difficult to handle, low yield and uneconomical

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A kind of method for continuously preparing vanillin and syringaldehyde of the present embodiment comprises the following steps:

[0025] 1. Bromination of p-Hydroxybenzaldehyde

[0026] 24.4 g (0.2 mol) of p-hydroxybenzaldehyde, 160 ml of methanol, and 250 ml of chloroform were successively added to the reactor, stirred, and cooled to 0-5° C. in an ice-water bath. Take 36.8 grams of bromine (0.23 moles), dissolve it in 75 milliliters of chloroform to make a solution, and slowly add it dropwise to the reactor for about 1.5-2 hours, and continue to react for 2.5 hours after the drop is completed. After the reaction was completed, nitrogen gas was used to blow off residual hydrogen bromide and bromine in the system to obtain a reaction complete solution.

[0027] Raise the temperature of the reaction-completed liquid, distill off chloroform and part of methanol to obtain the brominated product, which is directly used as a raw material for the synthesis of vanillin. The ...

Embodiment 2

[0033] The difference between this example and Example 1 is that it is used for the synthesis of ethyl vanillin.

[0034] The solvent methanol in Example 1 was replaced with ethanol, and the ethanol solution of 0.7 moles of sodium ethylate and 70 milliliters of ethanol were added to the reaction kettle of the bromination product (0.2 moles) and stirred to dissolve, and then 2.2 grams of basic copper carbonate, dimethylformaldehyde Amide (DMF) 12 grams, replace the air with nitrogen, raise the temperature to 110°C-120°C (pressure about 0.5MPa-0.6MPa), react for 4 hours, cool to room temperature to terminate the reaction. The ethanol was distilled off from the reaction mixture and recovered for reuse. Add 350 ml of water, 2 grams of powdered activated carbon, stir and heat up to 95°C, keep warm for decolorization, filter while hot, cool the filtrate to 60°C, neutralize with concentrated hydrochloric acid to PH=2-3, precipitate out, cool to 10°C, Filter, wash and dry to obtain t...

Embodiment 3

[0036] The differences between this embodiment and Embodiment 1 are:

[0037] Add 0.64 mole of sodium methylate (28% methanol solution), 50 milliliters of methanol, 10 milliliters of ethyl acetate in the bromination product (0.2 mole) reaction kettle of embodiment 1, stir well, then add cuprous chloride 2.0 successively gram. Introduce carbon dioxide for about 1 minute, airtightly heat up to 115°C-120°C (pressure about 0.6MPa-0.7MPa), react for 3 hours, cool to room temperature to terminate the reaction. Methanol was distilled off from the reaction mixture and recovered for reuse. Finally, the yield of vanillin was 89.5%, and the yield of syringaldehyde was 5.3%.

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Abstract

The invention relates to the technical field of organic synthesis, in particular to a method for continuously preparing vanillin and syringaldehyde. According to the method for continuously preparingthe vanillin and the syringaldehyde, the vanillin and the syringaldehyde are continuously synthesized and produced by taking the p-hydroxy benzaldehyde as the raw material, and the vanillin and the syringaldehyde are obtained by directly etherifying brominated products without refining in the process, so that the aims of shortening the process, improving the yield, reducing the cost, being safe and environment-friendly and easily realizing industrial production are achieved.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a method for continuously preparing vanillin and syringaldehyde. Background technique [0002] Vanillin is a class of bulk broad-spectrum spices, the chemical name is 3-alkoxy-4-hydroxybenzaldehyde; according to the different alkoxy groups, there are methyl vanillin (methoxy: -OCH3), ethyl Base vanillin (ethoxy: -OC2H5), etc.; mainly used in the preparation of various flavors and fragrances, food, beverages, daily necessities, and also in the synthesis of drugs and fine chemicals. [0003] Ways to obtain vanillin include natural raw material extraction and chemical synthesis. The former is far from being able to meet demand due to limited resources; traditional chemical production processes include eugenol method, sassafras oil method, lignin method, guaiacol-glyoxylic acid method, guaiacol-nitrosation method, all due to the process Disadvantages such as long routes, ...

Claims

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Application Information

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IPC IPC(8): C07C45/64C07C47/575C07C47/58
CPCC07C45/63C07C45/64C07C47/565C07C47/575C07C47/58
Inventor 孔繁昇刘占峰
Owner 孔繁昇
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