Scale-Up of the Nitration of 1-Acetyl-3,4-dichloro-1,2-(ethylenedioxy)benzene Using Nitric Acid/Trifluoroacetic Acid

The process development of the nitration of 3-acetyl-4,5-dichloro-1,2-(ethylenedioxy)benzene (1) to 3-acetyl-4,5-dichloro-1,2-(ethylenedioxy)-6-nitrobenzene (2) led to two potential scale-up processes. The two nitration processes were a solids addition to nitric acid and nitric acid addition to a trifluoroacetic acid solution. The detailed hazards safety evaluation of the two processes was carried out using abuse studies, CHETAH calculations, the reactive system screening tool, accelerating rate calorimetry, and differential scanning calorimetry. The nitric acid addition to a trifluoroacetic acid solution process was chosen because of the better safety profile. This process was successfully scaled up in a pharmaceutical pilot plant.