Continuous Synthesis Of Pendimethalin

Pendimethalin , which was firstly developed by American Cyanamiol Company,Trade names include AC92553,Accotab, Go-Go-San ,Herbadox,Penoxalin,Prowl,Sipaxol,Sovereign, Stomp and Way-Up.Acute oral LD₅₀ technical for rats,1250mg/kg. Acute dermal LD₅₀ for mice,1620mg/kg. Nocarcinogenic,(mutagenic and teratogenic effects at experimental dosage). High toxic to fish and aquatic organisms. Low toxic to bees and birds,oral LD₅₀ forbees 59.0mg/kg,acute oral LD₅₀ for wigeon 10g/kg?d .Acute oral LD₅₀ of 33% EC for ats2.9g/kg(male) and 2.7g/kg(female),acute dermal for male rabbits 6.8g/kg,acute inhale for r>475mg/m。Pendimethalin is a selective herbicide used to control most annual grasses and certain broadleaf weeds in field corn, potatoes,rice,cotton,soybeans,tobacco,peanuts and sunflowers. It is used both pre-emergence, that is before weed seeds have sprouted,and early post-emergence. Incorporation into the soil by cultivation or irrigation recommended within 7 days following application. Pendimethalin is available in emulsifiable concentrate,wet table powder,or dispersible granule formulations.In the article,N-(1-ethylpropyl)-3,4-dimethylaniline was used as starting material, we studied on the synthetic process of Nitrification by batch process。We determined the concentration of the nitric acid is 35%,The amount of nitric acid is N-(1-ethylpropyl)-3,4-dimethylaniline1.05 times, the reaction temperature is 40℃, the reaction time was 30min, the reaction was complete in the salifying process; in the nitrification process, We determined the concentration of the nitric acid is 55%,The amount of nitric acid is N-(1-ethylpropyl)-3,4-dimethylaniline 3 times, the reaction temperature is 46-55℃, the reaction time was 2.5h,at the same time ,we carried out a continuous stability test, the average level of Pendimethalin is 96.5%, with an average conversion rate of 79.8%。On this basis,We studied the synthetic process of Nitrification by continuous process,When the total flow is 1.2ml/min,it can be synthesized continuously Pendimethalin TC,the content of Pendimethalin is79.89%,Compared with the intermittent,the Content of product is higher 2%～3%,and the Nitrite content of Pendimethalin was less. In the process of denitrosation,We used FeCl₂·4H₂O as Scavenger to remove nitrosourea compounds of Pendimethalin TC, after 3h , the concentration of N-nitroso-Pendimethalin below the detection level about 100ppm。...