Preparation method of p-(methylthio)benzaldehyde

A technology of p-chlorobenzaldehyde and benzaldehyde, applied in the direction of mercaptan preparation, sulfide preparation, organic chemistry, etc., can solve the problems of increased difficulty in wastewater treatment, a large amount of organic impurities, poor operating conditions, etc., and achieve high product yield, The effect of high total yield and good industrialization prospects

Active Publication Date: 2020-01-21
SHANDONG GUOBANG PHARMA +1
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Problems solved by technology

But, be applied to bromine in the method (1), produce hydrobromic acid, have a large amount of waste acid to produce, and reaction is a high-temperature reaction, can produce a large amount of organic impurities in the production process, increased the wastewater treatment difficulty, simultaneously bromine is in production and There are certain safety risks in the transportation process, and the overall yield is only about 85%, and the cost is relatively high; method (2) has a simple reaction process, mild reaction conditions, and the overall yield can reach 88~92%, but in the first step In the reaction, sodium methyl mercaptide, which is one of the main raw materials, is easily hydrolyzed to release foul smell and extremely low threshold value of methyl mercaptan gas, which will inevitably produce foul smell and toxic pollutants, which has a great impact on the environment, and the operating conditions are relatively low. Difference

Method used

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  • Preparation method of p-(methylthio)benzaldehyde
  • Preparation method of p-(methylthio)benzaldehyde

Examples

Experimental program
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Embodiment 1

[0027] a. Take 412g (0.261mol) of 10% sodium thiosulfate solution and add it to a four-necked flask with mechanical stirring, add 0.63g (0.00227mol) tetrabutylammonium chloride, raise the temperature to 70°C, and throw in 31.95 g (0.227mol) p-chlorobenzaldehyde, reacted for 4 hours;

[0028] b. Add concentrated sulfuric acid to adjust pH=0, heat up to 90°C, and keep warm for 2 hours; then lower the temperature to 60°C, add 0.15g zinc powder, stir and keep warm for 2 hours; then add 32% liquid alkali dropwise to adjust pH=9.0, Stir for 1 hour;

[0029] c. Put the material into the autoclave, raise the temperature to 90°C, feed in methyl chloride, keep the pressure in the kettle at 0.5MPa, and keep it warm for 8 hours; after the heat preservation is over, cool it to 35°C, and put the material into the separatory funnel to stand still After 30 minutes, the lower organic phase was collected to obtain the product crude product; 31.95g sodium sulfate was added to absorb water in th...

Embodiment 2

[0031] The difference between this implementation method and Example 1 is that the phase transfer catalyst is the tetrabutylammonium bromide of 0.73g (0.00226mol), and other steps are identical, obtain 33.79g product, molar yield 97.70%, gas phase detection purity is 99.3%.

Embodiment 3

[0033] The difference between this implementation method and Example 1 is that the phase transfer catalyst is 0.67g (0.00227mol) tetrabutylphosphine chloride, other steps are the same, obtain 32.86g product, molar yield 95.03%, gas phase detection purity is 99.2%.

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Abstract

The invention discloses a preparation method of p-(methylthio)benzaldehyde, which comprises the following steps: generating a bunte salt by adopting sodium thiosulfate in place of sodium methyl mercaptide; and carrying out acid hydrolysis and methylation reactions to synthesize the p-(methylthio)benzaldehyde. According to the method, the defect that sodium methyl mercaptide is used as a substituting agent in an existing production process line is overcome, the smell problem in the using process of the sodium methyl mercaptide is effectively solved, the raw materials are cheap and easy to obtain, clean and free of pollution, the operation procedure is simple, the total yield is high, and good industrial prospects are achieved.

Description

technical field [0001] The invention belongs to the technical field of organic chemical synthesis, and also belongs to the technical field of synthesis of veterinary drugs and pharmaceutical raw materials, and relates to a method for synthesizing p-methylthiobenzaldehyde, an intermediate p-methylsulfonylbenzaldehyde, which is a raw material of florfenicol. Background technique [0002] Florfenicol (Florfenicol, also known as fluprofen, fluthiamphenicol) is a white or off-white crystalline powder, odorless, and bitter in taste. It is a new veterinary special chlorine that was successfully developed in the late eighties. Broad-spectrum antimicrobials. The main raw material of Florfenicol is D-p-thymphenylphenylserine ethyl ester (commonly known as D-ethyl ester). [0003] The synthesis of D-ethyl ester takes p-thymphenyl benzaldehyde as raw material, and there are two methods for p-thymphenyl benzaldehyde: (1) using p-thymphenyl toluene as the starting material, reacting with...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C319/14C07C323/22
CPCC07C319/02C07C319/14C07C381/02C07C323/22
Inventor 张小垒刘聪赵肖泽王召平
Owner SHANDONG GUOBANG PHARMA
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