Azeotropic compositions of methoxy-perfluoropropane and their use

An azeotropic composition consisting essentially of C3F7—OCH3 and a second component selected from the group consisting of an alkane or cycloalkane having 5 to 7 carbon atoms, said azeotropic composition is selected from one of the following compositions:

• (A) a composition consisting essentially of 69-72 weight percent n-C3F7—OCH3 and 28-31 weight percent n-pentane and having a boiling point of 24.8° C. +1° C. at a pressure of 735.8 mm Hg;
• (B) a composition consisting essentially of 82-84 weight percent n-C3F7—OCH3 and 16-18 weight percent 2,2-dimethylbutane and having a boiling point of 30.6° C.±1° C. at a pressure of 735.6 mm Hg;
• (C) a composition consisting essentially of 96.1-96.5 weight percent n-C3F7—OCH3 and 3.5-3.9 weight percent n-hexane and having a boiling point of 32.7° C.±1° C. at a pressure of 729.6mm Hg;
• (D) a composition consisting essentially of 95.8-96.2 weight percent n-C3F7—OCH3 and 3.8-4.2 weight percent methylcyclopentane and having a boiling point of 32.9° C.±1° C. at a pressure of 729.5 mm Hg;
• (E) a composition consisting essentially of 97.4-97.7 weight percent n-C3F7—OCH3 and 2.3-2.6 weight percent cyclohexane and having a boiling point of 33.3° C.±1° C. at a pressure of 735.8 mm Hg;
• (F) a composition consisting essentially of 99.2-99.8 weight percent n-C3F7—OCH3 and 0.2-0.6 weight percent n-heptane and having a boiling point of 33.4° C.±1° C. at a pressure of 729.3 mm Hg.