Butylated Hydroxytoluene
(bue' ti lay'' ted hye drox'' ee tol' ue een).
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C15H24O 220.35
Phenol, 2,6-bis(1,1-dimethylethyl)-4-methyl-;    
2,6-Di-tert-butyl-p-cresol     [128-37-0].
DEFINITION
Butylated Hydroxytoluene contains NLT 99.0% of C15H24O.
IDENTIFICATION
•  A. Infrared Absorption 197K: On undried sample
IMPURITIES
•  Residue on Ignition 281
Analysis:  Transfer 50 g 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-min periods to constant weight.
Acceptance criteria:  NMT 0.002%
•  Heavy Metals, Method II 231: NMT 10 ppm
•  Organic Impurities
Solution A:  50 mg/mL of potassium ferricyanide
Solution B:  105 mg/mL of ferric chloride
Sample solution:  20 mg/mL of Butylated Hydroxytoluene in methanol
Standard solution:  0.1 mg/mL of Butylated Hydroxytoluene from the Sample solution diluted with methanol
Chromatographic system 
Mode:  TLC
Absorbent:  0.25-mm layer of chromatographic silica gel mixture
Developing solvent system:  Methylene chloride
Application volume:  10 µL
Spray reagent:  Solution A, Solution B, and water (1:2:7), freshly prepared
Analysis 
Samples:  Sample solution and Standard solution
Apply the Samples, and allow to dry. Place the plate in the chromatographic chamber, and develop until the solvent front has moved three-fourths of the length of the plate. Remove the plate, and allow the plate to dry. Spray the plate with Spray reagent.
Acceptance criteria:  Any spot from the Sample solution, apart from the principal spot, is not more intense than the spot from the Standard solution (NMT 0.5%).
SPECIFIC TESTS
•  Congealing Temperature 651: NLT 69.2, corresponding to NLT 99.0% of C15H24O
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers.
•  USP Reference Standards 11
USP Butylated Hydroxytoluene RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
1-301-816-8335
(EXC2010) Monographs - Excipients
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 1718
Pharmacopeial Forum: Volume No. 34(1) Page 130