Research Of Cleaner Nitration Technique Of 4-Chloro-3, 5-Dinitrotrifluoromethylbenzene

The 4-chloro-3, 5-dinitrotrifluoromethylbenzen is an important intermediate, which can be synthesized into many kinds of herbicide. It is made from raw material of 4-chlorotrifluoromethylbenzene with two nitrifying processing. But in China the production of it always involves with the problems such as low efficiency, serious pollution.The research on the improvement nitrification of 4-chloro-3, 5-dinitrotrifluoromethylbenzen aims to make environmental-friendly production of it by reducing the amount of waste acid in the production. The following are the main focuses of this thesis paper:(1) The organic matters in the waste acid was tested by IR analysis and the results showed that they are mainly 4-chloro-3, 5-dinitrotrifluoromethylbenzen;Processing waste acid with leaching agent is a common method. With many tests the raw material is thought to be the best leaching agent.(2) On the base of the present production procedure, the introduction of sulfur trioxide to exchange the fuming sulphuric acid is aimed to reduce the discharge of sulphuric acid. The main influencing elements such as raw material ratio, reaction temperature, reaction time, the density of sulfur trioxide,the density of nitric acid, the mol of sulfur trioxide are tested with the orthogonal experiment and thus generate the best reaction conditions. Based on the result of (small scale test), project and enlarged test is conducted. The output rate of the product just boosts from 83% to 90.1%.(3) The test methods include: making use of the soft reaction conditions, reducing the reaction time, reducing the amount of raw material, using the ordinary segregation method, boost the output rate of the raw material. The concret method is the following: when the The achievements of this thesis paper involve: with the method of direct synthesizing, the ratio of raw material, reconversion percentage is over 90%, the reaction will be stopped, insulated,. The organic matter of the upper layer will be distilled with decompression. Then the product that dosen’t take part in reaction will be distilled and the content of it will be no more than 0.5%. The soft reaction conditions with the distillation makes the production of 4-chloro-3, 5-dinitrotrifluoromethylbenzen over 92.7%.(4)The introduction of output rate as water absorbing agent,minimize the amount waste acid; the soft reaction condition reduce the generation of byproducts and make the recycling of waste acid possible. The above two methods reduce the waste acid pollution and boost the output rate. So it is the cleanest production method of 4-chloro-3, 5-dinitrotrifluoromethylbenzen with present technological level.