Aminobenzotrifluoride (abbreviated as PTFMA, CAS registration number 455-14-1) is an important chemical raw material, especially widely used in pesticide and medicine. After chlorination of p-trifluoromethylaniline, 2,6-dichloro-p-aminotrifluoromethylbenzene can be obtained. It is an important intermediate. It is used in the agricultural chemicalbook pharmaceutical industry to synthesize high efficiency and low toxicity insecticides fipronil (regent), cyfluthrin, flufenuron, herbicides ethafluorin, ethyneflurin, etc., and in the pharmaceutical industry to synthesize a new immunosuppressive drug leflunomide, etc. With the continuous deepening of green chemical technology and new drug research, new uses have been continuously developed and have become important and promising chemical products.
As one of the important fine chemical products, p-trifluoromethylaniline can be used to synthesize a variety of pesticides. With the deepening of research on new varieties of pesticides, its application range is becoming more and more extensive. The product is chlorinated to obtain 2,6_ Dichlorop-aminotrifluoromethylbenzene, which is an important pesticide intermediate, is used in the synthesis of insecticide fipronil (regent), cypermethrin, fluorouracil, fungicide haloperidine, herbicide ibuprofen, etc. in the pesticide industry. Among them, Ruijinte has many outstanding advantages such as high efficiency, low toxicity, low residue and so on because of the introduction of fluorine-containing groups in its structure.
There are many ways to synthesize p-trifluoromethylaniline. According to the different raw materials, there are four main processes: p-nitrotrifluoromethylbenzene reduction, p-chlorotrifluoromethylaniline, high-pressure ammonolysis and trifluoromethylation. The most economical synthesis route is the high pressure ammonolysis of p-chlorotrifluoromethylbenzene.
CN101298421B provides a synthesis method of p-trifluoromethylaniline. p-chlorotrifluoromethylbenzene and liquid ammonia undergo ammonolysis reaction under the action of catalyst and acid binding agent to produce the p-trifluoromethylaniline. By weight, the catalyst is composed of 1 to 10 parts of cuprous chloride, 2 to 30 parts of potassium fluoride, and 5 to 30 parts of phase transfer catalyst. The amount of the catalyst added is 8 to 70% (mass) of p-chlorotrifluoromethylbenzene.
The invention adopts an efficient composite catalyst to provide a high single-pass conversion and economically feasible synthesis scheme for the synthesis of p-trifluoromethylaniline; The price of catalyst used in the synthesis process is low, and the organic solvent and phase transfer catalyst can be recycled and reused, and the production cost is low; The whole process has no wastewater discharge and is environmentally friendly.
Other preparation methods are as follows. In the method of p-nitrotoluene as raw material, p-nitrotoluene is used as raw material to brominate with bromine to produce p-dibromomethylnitrobenzene, which is then brominated with sodium hypobromate to produce p-tribromomethylnitrobenzene, which is then fluorinated with antimony trifluoride, and then reduced with tin dichloride to obtain p-trifluoromethylaniline. This method is a classic method. The raw materials used are easy to obtain, but bromination requires more bromine and only intermediate transition. It also requires SbF3 fluorination and SnCl2 reduction. The process is complex and there are many three wastes, which is difficult to industrialize. If chlorination can replace bromination, HF can be used for fluorination, and conventional reduction methods can be used for reduction, it will have certain industrial significance. P-trifluoromethylaniline is produced by the reaction of chlorotrifluoromethylbenzene and ammonia under high pressure and high temperature (150~240 ℃) with chemicalbook chlorotrifluoromethylbenzene as raw material. Although p-chlorotrifluoromethylbenzene has become an industrial commodity, the conditions for ammonolysis are harsh, and industrialization is difficult. P-trichloromethyl phenyl isocyanate is used as raw material to produce p-trifluoromethylaniline hydrofluorate by reaction of p-trichloromethyl phenyl isocyanate with hydrogen fluoride, and then react with alkali. This method is developed abroad in recent years, and p-trichloromethyl phenyl isocyanate can be produced from p-methylaniline by passing phosgene to generate p-trichloromethyl chloroformyl aniline, and further generate p-trichloromethyl phenyl isocyanate.