Method for synthesizing and preparing bronopol by one step

Abstract

The invention discloses a method for synthesizing and preparing bronopol by one step. The method comprises the steps of: (1) adding nitromethane, a formaldehyde solution and a solvent into a reaction vessel and mixing, adding liquid caustic soda into the mixture at the temperature of 0-20 DEG C, and then adding liquid bromine into the mixture until the reaction liquid is colorless, and adjusting the content of bromic acid in the reaction product to be less than 10ppm to obtain a crude product, wherein the molar ratio of nitromethane to formaldehyde in the formaldehyde solution to alkali in the caustic soda to the liquid bromine is 1:( 2.1-2.2): (1-1.1): (1-1.05); (2) putting the crude product obtained in the step (1) into a distillation tower for negative pressure distillation, so as to obtain distillation product in a tower kettle; and (3) centrifuging and drying the distillation product to obtain bronopol. The invention relates to the technical field of fine chemical engineering, and the method is short in reaction period, simple in production technology, low in production consumption and environmental pollution as well as high in product quality and yield.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a method for preparing bronopol through one-step synthesis. Background technique [0002] Bronopol (Bronopol), chemical name: 2-bromo-2-nitro-1,3-propanediol, also known as Bronopol, bronopol, bacteriostatic alcohol, Pi Lebao, etc. Bronopol is a white to pale yellow crystalline powder with a melting point of 120-123°C. It is easily soluble in water, ethanol, and propylene glycol, but insoluble in chloroform, acetone, and benzene. Bronopol is a broad-spectrum, high-efficiency, low-toxicity bactericidal preservative. It exerts antibacterial activity in a wide pH range and has a good inhibitory effect on yeast and mold, especially against Gram-positive bacteria with strong resistance. , The inhibitory effect on negative bacteria is outstanding. Because it can still maintain its antibacterial properties in cationic, nonionic surfactants and protein hydrolyzates, it is very s...

AI Technical Summary

Problems solved by technology

[0004] At present, only a small number of industrial production in China adopt the first production method. This method has no intermediate separation operation and the reaction is easy to control, but its disadvantages are that the product yield is not high and the purity is low, and it consumes a large amount of solvent and pollutes the environment.

[0005] At present, the second production method is commonly used in domestic industrial production. This process needs to be operated in two steps, and there will be a very pungent intermediate product bromonitromethane. The diffusion of the intermediate product bromonitromethane will lead to a poor working environment. The health of workers is adversely affected; the reaction cycle is long, the bromination reaction in the first step takes about 6 hours, and the hydroxyalkylation reaction in the second step takes 4 to 5 hours; the reaction needs to be carried out under ultra-low temperature conditions, if the reaction The higher the temperature, the lower the yield, which is not conducive to the control of production conditions. In order to achieve a suitable reaction temperature, the production consumption will inevitably be increased, and the difficulty of the production process will also be increased. In addition, in order to control the lower production temperature, a smaller The production container is generally a 100L reactor for reaction, the production efficiency is low, and the yield is only about 85wt%; formaldehyde is added in the follow-up production, so the amount of formaldehyde is not easy to control, so the product inevitably contains formaldehyde. At around 80ppm, if you want to deal with formaldehyde, you must carry out follow-up treatment, which prolongs the production process. The production process is longer and may not completely remove formaldehyde, resulting in lower product quality and limiting the application of the product in some demanding fields. At the same time, it has a great impact on the environment. With the international control of formaldehyde, the market competitiveness of products has declined

The intermediate product bromopicrin needs to be separated by distillation, and the filtered mother liquor also needs to be distilled, so that the whole production process is distilled twice, the production process is longer, the energy consumption is large, and the labor required is also large. increase the cost of production