A method and system for continuous production of 5-fluoro-2-nitrophenol

Abstract

The invention provides a method and system for continuously producing 5-fluoro-2-nitrophenol. The method comprises the steps: firstly, intensely mixing an alkali solution, 2,4-difluoronitrobenzene and a back-mixing solution, so as to obtain an intensely-mixed solution; then, enabling the intensely-mixed solution to enter a hydrolysis kettle for a reaction, so as to obtain reactant liquor; and then, recycling part of the obtained reactant liquor as the back-mixing solution, and acidifying the other part of the obtained reactant liquor, thereby obtaining 5-fluoro-2-nitrophenol. Through recycling the reaction-completed reactant liquor and mixing the raw materials through intense mixing, side reactions of a hydrolysis reaction are reduced, then, the yield of the reaction is increased, and meanwhile, waste gases, waste water and waste residues of the reaction are less.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method and system for continuous production of 5-fluoro-2-nitrophenol. Background technique [0002] 5-fluoro-2-nitrophenol, English name: 5-Fluoro-2-nitrophenol, molecular formula: C 6 h 4 FNO 3 , Molecular weight: 157, CAS: 446-36-6. 5-Fluoro-2-nitrophenol is an intermediate of the herbicide fluramid, which belongs to the phthalimide herbicide and is also a typical contact herbicides. It has been widely used in foreign agriculture. The domestic and foreign markets for flumechlor propargyl are vast, and there is an urgent need for a new production process for flumecil propargyl to meet the market demand. For this, the synthesis method and synthesis process of 5-fluoro-2-nitrophenol as an intermediate have also become a research topic. hotspot. [0003] At present, the relatively mature 5-fluoro-2-nitrophenol process method is as follows: using 2,4-difluoronitrobenzene a...

AI Technical Summary

Problems solved by technology

The yield of the existing synthesis process is only about 78%, and the remaining more than 20% of the raw materials generate some creosote such as 3-fluoro-4-nitrophenol, etc. The 5-fluoro-2-nitrophenol synthesis process still has consumption Due to the disadvantages of long time, high energy consumption, high production cost, and high risk factor, the research and development of new synthetic processes has become a hot spot in the field of synthetic research. For example, a preparation of 5-fluoro-2-nitrophenol was disclosed in the Journal of Chemical Technology and Development Method, the method uses 2,4-difluoronitrobenzene as the starting material, reacts with potassium hydroxide to hydrolyze to obtain potassium phenate, and then acidifies and purifies at room temperature to obtain 5-fluoro-2-nitrophenol. The cost is high, and the three wastes produced are more, so it is not suitable for large-scale industrial production

As another example, the World Journal of Pesticides discloses a preparation method of 5-fluoro-2-nitrophenol, which uses 2,4-difluoronitrobenzene as a starting material and reacts with sodium hydroxide to obtain Sodium phenate, and then acidify and purify at room temperature to obtain 5-fluoro-2-nitrophenol. The yield of this process route is relatively high, but it produces more three wastes and the output is small, and it is not suitable for large-scale industrial production.

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