C15H24O 220.35

Phenol, 2,6-bis(1,1-dimethylethyl)-4-methyl-.
2,6-Di-tert-butyl-p-cresol [128-37-0].

Packaging and storage— Preserve in well-closed containers.

Identification— To 10 mL of a solution in methanol (1 in 100,000) add 10 mL of water, 2 mL of sodium nitrite solution (3 in 1000), and 5 mL of dianisidine dihydrochloride solution (1 in 500), prepared by dissolving 200 mg of dianisidine dihydrochloride in a mixture of 40 mL of methanol and 60 mL of 1 N hydrochloric acid: an orange-red color develops within 3 minutes. Add 5 mL of chloroform, and shake: the chloroform layer exhibits a purple or magenta color, which fades when exposed to light.

Congealing temperature 651: not lower than 69.2, corresponding to not less than 99.0% of C15H24O.

Residue on ignition 281— Transfer about 50 g, accurately weighed, to a tared crucible, ignite until thoroughly charred, and cool. Moisten the ash with 1 mL of sulfuric acid, and complete the ignition by heating at 800 ± 25 for 15-minute periods to constant weight: the limit is 0.002%.

Heavy metals, Method II 231: 0.001%.

Organic volatile impurities, Method IV 467: meets the requirements. [NOTE—A G16 column has been shown to be an appropriate secondary column.]

Residual solvents 467: meets the requirements.

Expert Committee : (EM105) Excipient Monographs 1

USP29–NF24 Page 3286

Phone Number : 1-301-816-8262