Chemical Properties
white or light yellow waxy solid with an
Uses
Butylated Hydroxyanisole is an antioxidant consisting of a mixture of two isomers of tert-butyl-4-hydroxyanisole. Butylated Hydroxyanisole is used in food preservation as it antioxidant properties pre
vent food from becoming rancid. Butylated Hydroxyanisoleas is also used in animal feed, petroleum products, and cosmetics.
Uses
Antioxidant and preservative, especially in foods, cosmetics, pharmaceuticals; also rubber and petroleum products.
General Description
White, beige or slightly yellow waxy solid with an aromatic odor and a slightly bitter burning taste.
Air & Water Reactions
Insoluble in water.
Reactivity Profile
Butylated hydroxyanisole degrades with prolonged exposure to sunlight. Exhibits antioxidant properties and synergism with acids, BHT, propyl gallate, hydroquinone, methionine, lecithin and thiodipropionic acid. Butylated hydroxyanisole exhibits antioxidant properties as a scavenger of free radicals. Butylated hydroxyanisole is incompatible with oxidizing agents and ferric salts.
Fire Hazard
Butylated hydroxyanisole is combustible.
Hazard
Toxic by ingestion. Use in foods restricted;
consult FDA regulations.
Shipping
UN2811 Toxic solids, organic, n.o.s., Hazard
Class: 6.1; Labels: 6.1—Poisonous materials, Technical
Name Required. UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9—
Miscellaneous hazardous material, Technical Name Required
Description
Butylated hydroxyanisole (BHA) is an antioxidant
widely used in food. Because it is contained in pastry,
it can induce sensitization in caterers.
Waste Disposal
Suggested: Dispose of contents and container to an approved waste disposal plant. All federal, state,
and local environmental regulations must be observed.
Occurrence
BHA is not known to occur as a natural product.
Production Methods
Prepared by the reaction of p-methoxyphenol with isobutene.
Aroma threshold values
Detection: 3 ppm
Pharmaceutical Applications
Butylated hydroxyanisole is an antioxidant with some
antimicrobial properties. It is used in a wide range of cosmetics,
foods, and pharmaceuticals. When used in foods, it is used to delay
or prevent oxidative rancidity of fats and oils and to prevent loss of
activity of oil-soluble vitamins.
Butylated hydroxyanisole is frequently used in combination with
other antioxidants, particularly butylated hydroxytoluene and alkyl
gallates, and with sequestrants or synergists such as citric acid.
FDA regulations direct that the total content of antioxidant in
vegetable oils and direct food additives shall not exceed 0.02% w/w
(200 ppm) of fat or oil content or essential (volatile) oil content of
food.
USDA regulations require that the total content of antioxidant
shall not exceed 0.01% w/w (100 ppm) of any one antioxidant or
0.02% w/w combined total of any antioxidant combination in
animal fats.
Japanese regulations allow up to 1 g/kg in animal fats.
Safety
Butylated hydroxyanisole is absorbed from the gastrointestinal tract
and is metabolized and excreted in the urine with less than 1%
unchanged within 24 hours of ingestion. Although there have
been some isolated reports of adverse skin reactions to butylated
hydroxyanisole, it is generally regarded as nonirritant and
nonsensitizing at the levels employed as an antioxidant.
Concern over the use of butylated hydroxyanisole has occurred
following long-term animal feeding studies. Although previous
studies in rats and mice fed butylated hydroxyanisole at several
hundred times the US-permitted level in the human diet showed no
adverse effects, a study in which rats, hamsters, and mice were fed
butylated hydroxyanisole at 1–2% of the diet produced benign and
malignant tumors of the forestomach, but in no other sites.
However, humans do not have any region of the stomach
comparable to the rodent forestomach and studies in animals that
also do not have a comparable organ (dogs, monkeys, and guinea
pigs) showed no adverse effects. Thus, the weight of evidence does
not support any relevance to the human diet where butylated
hydroxyanisole is ingested at much lower levels. The WHO
acceptable daily intake of butylated hydroxyanisole has been set at
500 μg/kg body-weight.
LD50 (mouse, oral): 1.1–2.0 g/kg
LD50 (rabbit, oral): 2.1 g/kg
LD50 (rat, IP): 0.88 g/kg
LD50 (rat, oral): 2.0 g/kg
Synthesis
Several methods are used for the commercial production of BHA. Methylation of hydroquinone yields an intermediate
that gives a mixture of 3-BHA and 2-BHA upon treatment with tert-butyl alcohol and phosphoric acid. Butylation of hydroquinone
and subsequent methylation with dimethyl sulfate and sodium hydroxide can also be used to produce a mixture of the two BHA isomers.
In addition BHA can be synthesized by the tert-butylation of 4-methoxyphenol over silica or alumina at 150°C.
Carcinogenicity
Butylated hydroxyanisole (BHA) is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.
Environmental Fate
The metabolites of BHA can bind to cellular macromolecules,
such as proteins and DNA, and cause toxicity.
storage
Exposure to light causes discoloration and loss of activity. Butylated
hydroxyanisole should be stored in a well-closed container,
protected from light, in a cool, dry place.
Toxicity evaluation
BHA is a white or slightly yellow, waxy solid with a characteristic
odor. It is insoluble in water, but soluble in fats, oils,
and solvents like petroleum ether, chloroform, and alcohol.
Its octanol/water partition coefficient is 3.50; vapor pressure is
2.48×10-3 mm Hg at 25°C; and Henry’s law constant is
1.17×10-6 atm-m3 mol-1.
BHA is released into the environment through waste
streams. It has low soil mobility and volatilizes slowly from
water. It may bioconcentrate in aquatic organisms, adsorb to
sediment, and be subject to direct photolysis.
Incompatibilities
Butylated hydroxyanisole is phenolic and undergoes reactions
characteristic of phenols. It is incompatible with oxidizing agents
and ferric salts. Trace quantities of metals and exposure to light
cause discoloration and loss of activity.
Regulatory Status
GRAS listed. Accepted as a food additive in Europe. Included in the
FDA Inactive Ingredients Database (IM and IV injections, nasal
sprays, oral capsules and tablets, and sublingual, rectal, topical, and
vaginal preparations). Included in nonparenteral medicines licensed
in the UK. Included in the Canadian List of Acceptable Nonmedicinal
Ingredients.
