C6H12O 100.16

2-Pentanone, 4-methyl-.
4-Methyl-2-pentanone [108-10-1].

Packaging and storage— Preserve in tight containers.

Identification— The IR absorption spectrum of a thin film of it between sodium chloride crystals exhibits maxima, among others, at the following wavelengths, in µm: 5.81 (vs), 6.80 (m), 7.00 (m), 7.09 (m), 7.29 (vs), 7.72 (m), 8.06 (m), 8.31 (sh), 8.53 (s), and 8.91 (m).

Specific gravity 841: not more than 0.799, indicating not less than 99.0% of C6H12O.

Distilling range, Method I 721: between 114 and 117, a correction factor of 0.046 per mm being applied as necessary.

Acidity— Mix 15.0 mL with 15 mL of neutralized alcohol, add phenolphthalein TS, and titrate with 0.050 N sodium hydroxide: not more than 0.40 mL is required for neutralization.

Limit of nonvolatile residue— Evaporate 50 mL in a tared porcelain dish on a steam bath, and dry at 105 for 1 hour: the weight of the residue does not exceed 4 mg (0.008%).

Topic/Question	Contact	Expert Committee
Monograph	Robert H. Lafaver, B.A. Scientist 1-301-816-8335	(EM105) Excipient Monographs 1

USP32–NF27 Page 1281