Svaret på DCM frågan står i USPatent 3,981,975:
Citat:
A method for preparing anhydrous nitric acid comprising extracting an aqueous mixture of nitric acid and sulfuric acid with methylene chloride to yield a solution of anhydrous nitric acid in methylene chloride. The anhydrous nitric acid can be isolated from the methylene chloride by distillation or crystallization. Alternatively, the anhydrous solution of nitric acid in methylene chloride may be used directly. The methylene chloride extract of the nitric acid-sulfuric acid mixture is a useful nitrating agent.
Och ett eksempel:
Citat:
A solution was prepared by mixing 53.0 ml of 70 percent nitric acid with 47.0 ml of 96 percent sulfuric acid. The aqueous acid mixture was then extracted with 300 ml of methylene chloride. The methylene chloride raffinate was then analyzed. The methylene chloride contained 27.3 gms (51.8 percent) of anhydrous nitric acid and only a trace quantity of sulfuric acid. This may be compared to 31.2 gm (59.3 percent) which was obtained for three 100 ml extractions.
Dessutom ges ett eksempel, som visar att andra klorerade kolväten inte funkar alls, jämfört med MeCl2. Men som sagt - för att hålla oss på topic - så är ämnet förbjuden många ställen på grund av dets cancerframkallande- och reproduktionsskadande effekt.