Butylated hydroxyanisole

Description

Butylated hydroxyanisole (BHA) is an antioxidant widely used in food. Because it is contained in pastry, it can induce sensitization in caterers.

Chemical properties

white or light yellow waxy solid with an

Chemical properties

Log Kow 5. 3. Values above 3.0 are likely to bioaccumulate in aquatic organisms

Chemical properties

Butylated hydroxyanisole occurs as a white or almost white crystalline powder or a yellowish-white waxy solid with a faint, characteristic aromatic odor.

Chemical properties

BHA and BHT (butylated hydroxytoluene) are monohydric phenolic antioxidants that, prior to their introduction and acceptance in the food industry, were used to protect petroleum against oxidative degumming. Chemically, BHA is a mixture of two isomers, 3-tertiary-butyl-4-hydroxyanisole (90%) and 2-tertiary-butyl-4-hydroxyanisole (10%). Both BHA and BHT assert a good carry-through effect, although BHA is slightly better than BHT in this respect. BHT is, however, more effective in suppressing oxidation of animal fats than vegetable oils. Among its multiple applications, BHA is particularly useful in protecting the flavors and color of essential oils and is considered the most effective of all food-approved antioxidants for this application. BHA is particularly effective in controlling the oxidation of short-chain fatty acids, such as those found in coconut and palm kernel oils that are used typically in cereal and confectionary products.

Occurrence

BHA is not known to occur as a natural product.

The Uses of Butylated hydroxyanisole

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.

The Uses of Butylated hydroxyanisole

Antioxidant and preservative, especially in foods, cosmetics, pharmaceuticals; also rubber and petroleum products.

The Uses of Butylated hydroxyanisole

BHA (butylated hydroxy anisole) is a preservative with anti-oxidant capabilities, not to be confused with beta hydroxy acids (BHAs).

The Uses of Butylated hydroxyanisole

Butylated Hydroxyanisole (BHA) is an antioxidant that imparts stability to fats and oils and should be added before oxidation has started. It is a mixture of 3-tert-butyl-4-hydroxyanisole and 2-tertbutyl-4-hydroxyanisole. In direct addition, the fat or oil is heated to 60–70°C and the BHA is added slowly under vigorous agitation. The maximum concentration is 0.02% based on the weight of the fat or oil. It may protect the fat-soluble vitamins A, D, and E. It is used singly or in combination with other antioxidants. It is used in cereals, edible fat, vegetable oil, confectionary products, and rice.

What are the applications of Application

Butylated hydroxyanisole is an industrial antioxidant

Definition

A mixture of 2- and 3-tert-4-methoxyphenol.

Production Methods

Prepared by the reaction of p-methoxyphenol with isobutene.

Aroma threshold values

Detection: 3 ppm

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.

Hazard

Toxic by ingestion. Use in foods restricted; consult FDA regulations.

Fire Hazard

Butylated hydroxyanisole is combustible.

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.

Contact allergens

BHA is an antioxidant widely used in cosmetics and food. Contained in pastry, it can induce sensitization in caterers.

Safety Profile

Confirmed carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data. Moderately toxic by ingestion and intraperitoneal routes. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits acrid and irritating fumes

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.

Chemical property

Butylated hydroxyanisole (BHA) is a monohydric phenolic antioxidant found as a mixture of two isomeric compounds, 2-tert-butyl-4-hydroxyanisole (2-BHA) and 3-tert-butyl-4-hydroxyanisole (3-BHA); in commercial mixtures, the latter isomer is found in greater quantities than the former at a ratio of 9:1 and is preferred for its antioxidant properties. BHA is a crystalline or waxy solid that can be white or slightly yellow in colour and has a faint, characteristic odour. It is freely soluble in alcohols, such as ethanol, and in petroleum ether, chloroform, fats, oils, and propylene glycol, but it is insoluble in water. It melts at temperatures ranging from 48 to 63 degrees Celsius.

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.

Toxicity

The National Toxicology Program determined that Butylated Hydroxyanisole (BHA) is reasonably anticipated to be a carcinogen. California listed BHA as a carcinogen on the Proposition 65 list. The International Agency for Research on Cancer (IARC) concluded that there is sufficient evidence for the carcinogenicity of BHA in animals but that there are not enough data to classify its carcinogenicity in humans. BHA is listed as a category 1 endocrine disrupting chemical on the European Union (EU) list of potential endocrine disruptors.

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.

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

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.

Waste Disposal

Suggested: Dispose of contents and container to an approved waste disposal plant. All federal, state, and local environmental regulations must be observed.

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.