Butylated hydroxyanisole
[CAS# 25013-16-5]

Identification

• Classification: Natural product >> Natural phenols
• Name: Butylated hydroxyanisole
• Synonyms: 3(2)-tert-Butyl-4-hydroxyanisole; 2(3)-tert-Butyl-4-methoxyphenol; BHA
• Molecular Formula: C₁₁H₁₆O₂
• Molecular Weight: 180.25
• CAS Registry Number: 25013-16-5
• EC Number: 246-563-8
• FEMA: 2183
• SMILES: CC(C)(C)C1=C(C=CC(=C1)OC)O

Properties

• Melting point: 104 - 105 ºC (Expl.)
• Boiling point: 264-270 ºC
• Flash point: 130 ºC
• Water solubility: <0.1 g/100 mL at 18.5 ºC. 10 mM in DMSO (Expl.)

Safety Data

• Hazard Symbols: GHS07;GHS08;GHS09 Warning
• Hazard Statements: H315-H319-H351-H361-H411
• Precautionary Statements: P203-P264-P264+P265-P273-P280-P302+P352-P305+P351+P338-P318-P321-P332+P317-P337+P317-P362+P364-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Carcinogenicity	Carc.	2	H351
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Reproductive toxicity	Repr.	2	H361
Reproductive toxicity	Repr.	2	H361f
Serious eye damage	Eye Dam.	1	H318
Carcinogenicity	Carc.	1B	H350
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H410
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Specific target organ toxicity - single exposure	STOT SE	3	H336
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Specific target organ toxicity - single exposure	STOT SE	1	H370
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H411

Discovory and Applicatios

Butylated hydroxyanisole (BHA) is a synthetic antioxidant widely used in the food, pharmaceutical, and cosmetic industries. It is a waxy solid mixture of two isomers: 3-tert-butyl-4-hydroxyanisole and 2-tert-butyl-4-hydroxyanisole. The compound was first developed in the mid-20th century as part of research into synthetic antioxidants that could prolong the shelf life of fats and oils by preventing oxidative rancidity. BHA is derived from 4-methoxyphenol through tert-butylation using isobutylene under acidic conditions.

The discovery of BHA was driven by the need for more effective preservatives in processed food products. Natural antioxidants such as vitamin E and certain polyphenols, while effective, were either too costly or unstable under processing conditions. Synthetic alternatives like BHA and its structural analog butylated hydroxytoluene (BHT) offered greater thermal stability and compatibility with a variety of food systems. BHA quickly became approved for use in food products in many countries, and it was included in regulatory frameworks for food additives by organizations such as the United States Food and Drug Administration and the European Food Safety Authority.

BHA is primarily used to prevent the oxidation of fats and oils in foods. It is especially effective in high-fat products such as snack foods, baked goods, margarine, and preserved meats. By scavenging free radicals and stabilizing peroxyl radicals formed during lipid peroxidation, BHA slows the degradation of unsaturated fats, thereby preserving flavor, color, and nutritional value. Its antioxidant activity also helps prevent the formation of potentially harmful secondary oxidation products.

In the pharmaceutical industry, BHA is used to stabilize formulations that contain lipophilic active ingredients or excipients prone to oxidative degradation. It helps extend the shelf life of vitamins, particularly vitamin A and vitamin D, and other fat-soluble compounds. In cosmetics and personal care products, BHA is added to products such as lipsticks, moisturizers, and sunscreens to prevent rancidity of oils and waxes, contributing to longer product stability and consumer safety.

The compound has also been utilized in the polymer and rubber industries to protect materials against oxidative damage during processing and storage. BHA's compatibility with various organic materials makes it suitable as an additive in plasticizers, lubricants, and packaging materials.

Toxicological studies and regulatory reviews have been conducted extensively on BHA due to its widespread use in consumer products. Acceptable daily intake levels have been established by health authorities based on long-term feeding studies in laboratory animals. While BHA has been associated with certain biological effects at high doses in animal models, its use at regulated levels in foods and consumer goods is generally considered safe. Some jurisdictions require labeling of BHA-containing products for consumers seeking to avoid synthetic additives.

Despite occasional debate over its health implications, BHA remains a legally permitted additive in many parts of the world. Its low cost, effectiveness, and chemical stability continue to support its role in modern manufacturing practices. The compound is typically used in combination with other antioxidants such as BHT or citric acid to achieve synergistic effects and broader protection across various product formulations.

BHA is stable under typical processing conditions and resists volatilization and decomposition during baking or frying, making it particularly valuable in high-temperature food applications. Its antioxidant efficiency is dependent on concentration, medium polarity, and the presence of other antioxidants or pro-oxidants.

The role of butylated hydroxyanisole in food preservation, pharmaceuticals, and cosmetics illustrates the importance of antioxidant technology in modern industrial chemistry. Its continued use reflects a balance between efficacy, safety, and regulatory oversight based on decades of scientific evaluation and practical application.

References

1951. Alkyl hydroxyanisoles as antioxidants. Journal of the American Oil Chemists' Society, 28(5).
DOI: 10.1007/bf02646544

2024. Polycaprolactone/polylactic acid nanofibers incorporated with butyl hydroxyanisole /HP-β-CD assemblies for improving fruit storage quality. International Journal of Biological Macromolecules, 285.
DOI: 10.1016/j.ijbiomac.2024.137637

2025. BBCEAS-HLPC measurements for synthetic antioxidants (TBHQ, BHA, and BHT) in deep-UV region below 300 nm. Food Chemistry, 469.
DOI: 10.1016/j.foodchem.2024.142150