Process for making pentachloronitrobenzene

The process for producing pentachloronitrobenzene comprising

• reacting pentachlorobenzene with substantially pure nitric acid at a temperature from about 40.degree. to about 85.degree. C, with the provisos that
• i. a weight ratio of said nitric acid to said pentachlorobenzene of at least about 3.0:1 is employed when the reaction is effected at a temperature in the range of about 40.degree. to about 49.degree. C;
• ii. a weight ratio of said nitric acid to said pentachlorobenzene of at least about 2.5:1 is employed when the reaction is effected at a temperature in the range of about 50.degree. to about 59.degree. C;
• iii. a weight ratio of said nitric acid to said pentachlorobenzene of at least about 2.0:1 is employed when the reaction is effected at a temperature in the range of about 60.degree. to about 75.degree. C;
• and
• iv. a weight ratio of said nitric acid to said pentachlorobenzene in the range of about 2.0:1 to 3.5:1 is employed when the reaction is effected at a temperature in the range of about 76.degree. to about 85.degree. C.