Antioxidant BBMC
[CAS# 85-60-9]

Identification

• Classification: Catalysts and additives >> Antioxidant
• Name: Antioxidant BBMC
• Synonyms: 4,4'-Butylidenebis(6-tert-butyl-3-methylphenol)
• Molecular Formula: C₂₆H₃₈O₂
• Molecular Weight: 382.58
• CAS Registry Number: 85-60-9
• EC Number: 201-618-5
• SMILES: CCCC(C1=CC(=C(C=C1C)O)C(C)(C)C)C2=CC(=C(C=C2C)O)C(C)(C)C

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Melting point: 211 ºC (Expl.)
• Boiling point: 475.5±40.0 ºC 760 mmHg (Calc.)^*
• Flash point: 196.8±21.9 ºC (Calc.)^*
• Index of refraction: 1.539 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Hazard Statements: H315-H319-H335-H410-H412-H413
• Precautionary Statements: P261-P264-P264+P265-P271-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovory and Applicatios

Antioxidant BBMC, chemically known as 2-tert-butyl-4-methyl-6-(3,5-di-tert-butyl-4-hydroxybenzyl)phenol, is a highly effective sterically hindered phenolic antioxidant widely used in polymer stabilization. It belongs to the family of bisphenol-based antioxidants that offer outstanding protection against thermal oxidative degradation in organic substrates such as plastics, synthetic rubbers, adhesives, and resins. Its design incorporates multiple tert-butyl groups and phenolic hydroxyl groups, which together confer both high thermal stability and long-term resistance to oxidation.

The compound’s structure includes a benzyl linkage connecting two aromatic rings—one being a substituted hydroxyphenyl ring and the other a tert-butylated and methylated phenol. The steric bulk provided by the tert-butyl groups around the phenolic OH groups hinders the accessibility of oxidizing agents and enhances the molecule’s resistance to decomposition under elevated processing temperatures. Moreover, the benzyl bridge contributes to the overall rigidity and durability of the antioxidant molecule.

Antioxidant BBMC functions by donating a hydrogen atom from its phenolic OH groups to neutralize free radicals, thereby interrupting the autoxidation chain reactions that lead to polymer degradation. This mechanism allows it to act as a primary antioxidant, particularly effective in inhibiting the initiation and propagation phases of oxidation. Because of its molecular structure, BBMC is also less prone to volatilization and migration, making it particularly useful in applications requiring low extractables or long service life.

The development of BBMC was part of a broader effort in the polymer additives industry to address the limitations of earlier antioxidants, such as discoloration, limited thermal stability, and volatility during high-temperature processing. BBMC’s enhanced molecular weight and steric shielding make it suitable for use in demanding processing environments, such as the manufacture of polyolefins, styrenics, polyesters, and engineering plastics.

In practical applications, BBMC is often used in conjunction with secondary antioxidants such as phosphites or thioethers to achieve synergistic stabilization. While BBMC interrupts the radical chain reactions, secondary antioxidants decompose hydroperoxides, which are the precursors to free radicals. This dual-stabilization approach ensures a broader and more robust protection during both processing and long-term aging.

BBMC’s physical properties include good compatibility with a wide range of polymers and low volatility, which reduces loss during extrusion, molding, or other high-temperature processing steps. It is typically incorporated into the polymer matrix at low concentrations, often between 0.1% and 0.5% by weight, depending on the stability requirements and the specific application environment.

Because of its low toxicity and high efficacy, BBMC is often selected for use in consumer product packaging, automotive components, electrical insulation, and construction materials. Additionally, it finds application in coatings and sealants, where resistance to yellowing, embrittlement, and surface degradation is crucial. It is generally supplied as a crystalline solid or a fine powder and is soluble in organic solvents such as toluene, acetone, and chloroform, allowing for flexible formulation options.

Synthesis of BBMC involves the alkylation of a 2,6-substituted phenol with a hindered hydroxybenzyl halide under basic conditions. This process requires careful control of temperature and reagent ratios to ensure the formation of the desired mono-benzylated product without over-alkylation or oxidation of the sensitive phenolic moieties.

Overall, Antioxidant BBMC is a valuable stabilizing agent in advanced material systems where long-term durability, color retention, and resistance to heat and oxidation are critical. Its combination of structural stability, functional efficiency, and formulation versatility continues to make it a preferred choice in polymer additive systems.

References

1981. Effects of four bisphenolic antioxidants on lipid contents of rat liver. Toxicology Letters.
DOI: 10.1016/0378-4274(81)90142-9

1997. Comparison of two antioxidants for poly(etherurethane urea) in an accelerated in vitro biodegradation system. Journal of Biomedical Materials Research.
DOI: 10.1002/(sici)1097-4636(19970315)34:4<493::aid-jbm10>3.0.co;2-e

2005. Male reproductive toxicity of four bisphenol antioxidants in mice and rats and their estrogenic effect. Archives of Toxicology.
DOI: 10.1007/s00204-005-0033-5