Industrial grade: 98%; Food grade: 99% Butylated Hydroxytoluene CAS 128-37-0

What is BHT? How does it work?

BHT, short for Butylated hydroxytoluene, is a synthetic phenolic compound with the CAS number 128-37-0. It is a white crystalline powder, practically insoluble in water but highly soluble in oils and fats. It is a fat-soluble antioxidant approved for use in food. It protects oily foods from spoilage by capturing free radicals with its phenolic hydroxyl groups and breaking the chain reaction of oil oxidation – this is its core ability to preserve the shelf life and flavor of potato chips, chewing gum, and cooking oils.

Basic information : Chinese name: Butylated hydroxytoluene (also known as dibutylhydroxytoluene); English name: Butylated hydroxytoluene (abbreviation BHT); CAS number: 128-37-0; Molecular formula: C15H24O; Molecular weight: 220.35; Melting point: approximately 70℃; Boiling point: approximately 265℃; Other names: BHT, 2,6-di-tert-butyl-4-methylphenol, etc.

Structurally , BHT's full chemical name is 2,6-di-tert-butyl-4-methylphenol: a phenolic hydroxyl group (-OH) is attached to position 1 of the benzene ring, a tert-butyl group (-C(CH3)3) is attached to positions 2 and 6, and a methyl group (-CH3) is attached to position 4. The two large tert-butyl groups on either side of the phenolic hydroxyl group form significant steric hindrance, keeping the phenolic hydroxyl group in a "protected" state. This "hindered phenol" structure is the core structural feature that distinguishes BHT from ordinary phenolic compounds, and it also determines that the free radical it generates after donating hydrogen is exceptionally stable.

physical properties , BHT is a white crystalline or crystalline powder with a faint, distinctive odor; it is almost insoluble in water but readily soluble in ethanol, ether, acetone, benzene, and organic media such as animal and vegetable oils and mineral oils, making it a typical fat-soluble substance; its melting point is about 70°C and its boiling point is about 265°C. When heated, it melts into a colorless to pale yellow transparent liquid and can evaporate with water vapor.

Chemically , BHT is a hindered phenolic antioxidant: the hydrogen atom on its phenolic hydroxyl group is easily captured by free radicals (hydrogen donation), transforming the active free radical into a stable product, thereby terminating the chain reaction of oil oxidation; after hydrogen donation, BHT itself transforms into a phenoxy radical, which is difficult to initiate a new oxidation reaction due to the steric hindrance of the two tert-butyl groups, thus its antioxidant effect is long-lasting; BHT is chemically stable and heat-resistant, and can be used in high-temperature processing such as frying and baking, but it is sensitive to light and will gradually change color after prolonged storage or exposure to light.

Why does BHT play these roles in the food industries such as oils, baking, confectionery, and meat products? Its mechanism of action mainly includes the following:

Phenolic hydroxyl group hydrogen donation chain scission mechanism : Oil oxidation is a chain reaction of free radicals. The phenolic hydroxyl group of BHT provides hydrogen atoms to the peroxide free radical in the reaction, deactivating it into hydroperoxide. The free radical chain is thus broken, and the rate of oil oxidation decreases significantly. This is the fundamental action of all the antioxidant effects of BHT.

Hindered phenol radical passivation mechanism : After hydrogen donation, BHT becomes a phenoxy radical. Two large tert-butyl groups surround the radical center like a shield, making it difficult for it to react with oil molecules. Therefore, BHT does not produce "secondary catalysis" like ordinary phenols, and can maintain protection for a long time with a single hydrogen donation.

Fat-soluble partitioning mechanism : BHT is almost insoluble in water but highly soluble in fats and oils. After addition, it can dissolve uniformly and reside in the fat phase, directly intercepting free radicals in the oil phase, unlike water-soluble antioxidants which are confined to the aqueous phase. Therefore, it is particularly suitable for oil-containing systems such as vegetable oils, margarine, and fried foods.

Synergistic antioxidant mechanism : When BHT is combined with food antioxidants such as BHA (butylated hydroxyanisole), propyl gallate, and citric acid, the components can regenerate each other. Citric acid and other substances can also chelate trace metal ions that promote lipid oxidation. The total antioxidant effect of the compound system is stronger than that of single addition, and the same protection can be achieved at a lower dosage.

Heat-resistant and long-lasting protection mechanism : BHT has a melting point of about 70°C and a boiling point of about 265°C. It is not easily decomposed and volatilized during high-temperature processing such as frying and baking. It can be retained in the finished product and continue to play a role during the storage period at room temperature, covering the entire cycle from processing to shelf.

 All Uses of BHT

1. Edible oils and fat products sector

Edible vegetable oils and blended oils

It can be added directly to oils to block the oxidation chain reaction, delay rancidity and the formation of rancidity, and extend shelf life and shelf life after opening.

Corresponding products: vegetable oil, blended oil, shortening, margarine, etc.

Frying oil and fried foods

It continuously protects the oil during frying, prevents high-temperature oxidation from producing unpleasant flavors, and extends the lifespan of frying oil.

Corresponding products: frying oil, fried dough sticks, fried dough sticks, etc.

2. Grains, Baking, and Nuts

Breakfast cereals and instant oatmeal

It protects the unsaturated fats in the grain germ and oats, prevents oxidation, and maintains a crisp texture.

Corresponding products: instant oatmeal, breakfast cereals, rolled oats, etc.

Baked Pastries and Nuts

To prevent nuts from developing a stale, oily taste, maintain the crispness of biscuits and pastries, and extend the shelf life of seasonal foods such as mooncakes.

Corresponding products: biscuits, cookies, pastries, nuts, mooncakes, etc.

3. Confectionery and chewing gum sector

Chewing gum and bubble gum

It stabilizes the oil components in the flavoring, prevents the flavoring from oxidizing and losing its flavor, and maintains a consistent flavor over long-term chewing.

Corresponding products: chewing gum, bubble gum, etc.

Oily candies

To prevent the oxidation of oils and flavorings in candy, thus preserving its flavor and texture.

Corresponding products: hard candy, soft candy, toffee, etc.

4. Instant noodles and fast food sector

Instant noodles and fried dough cakes

It protects the oil in fried dough cakes and prevents oxidation during storage, which can produce unpleasant odors.

Corresponding products: instant noodles, instant rice vermicelli, instant rice noodles, etc.

Oily pre-prepared and frozen foods

It protects the oil components in prepared dishes and frozen foods, and slows down flavor deterioration.

Corresponding products: frozen dumplings, pre-cooked dishes, frozen prepared foods, etc.

5. Meat products and cured meat products sector

Cured meat products

It slows down fat oxidation and inhibits color darkening and flavor deterioration.

Corresponding products: cured pork, sausage, bacon, etc.

Sausages and jerky

Combined with packaging technology, it extends shelf life and maintains flavor.

Corresponding products: sausages, dried meat, meat jerky, etc.

6. Food flavoring and fragrance industry

Edible flavorings

To prevent the easily oxidized components of aldehydes and ketones in the flavoring from deteriorating, and to maintain the freshness of the aroma and batch consistency.

Corresponding products: food flavorings, food seasonings, etc.

Natural Flavor Essential Oils

To prevent flavorful essential oils such as lemon oil and peppermint oil from oxidizing and losing their aroma.

Corresponding products: lemon oil, peppermint oil, flavor essential oils, etc.

7. Health food industry

Fish oil supplements

It protects fish oil and easily oxidized nutrients such as unsaturated fatty acids, preventing a decline in their potency.

Corresponding products: fish oil soft capsules, compound nutritional supplements, etc.

Functional oil products

It protects easily oxidized functional oils such as DHA and EPA, and maintains the stability of active ingredients.

Corresponding products: DHA algal oil products, EPA fish oil products, etc.

8. Food Packaging Materials

Food-grade plastic packaging

It acts as an antioxidant in the processing of plastics such as cling film and food packaging bags, delaying plastic aging and controlling migration.

Corresponding products: cling film, food packaging bags, food containers, etc.

Waxed packaging paper

To prevent the wax layer of food wax paper and waxed packaging from oxidizing and turning yellow.

Corresponding products: food wax paper, waxed packaging paper, etc.

 Summary

BHT (Butylhydroxytoluene, CAS 128-37-0) is a hindered phenolic lipid-soluble antioxidant with the chemical name 2,6-di-tert-butyl-4-methylphenol. Its single phenolic hydroxyl group and two sterically hindered tert-butyl groups allow it to efficiently capture free radicals while simultaneously deactivating its own free radicals, thus effectively blocking the chain reaction of lipid oxidation. As a food-grade antioxidant, it protects oil-containing foods—from vegetable oils and potato chips to chewing gum, cured meats, and fish oil capsules—in extremely low doses, preventing spoilage, maintaining flavor, and extending shelf life. Understanding its hindered phenolic structure explains why it can simultaneously serve as a core antioxidant in numerous food sectors, including oils, baking, confectionery, meat products, flavorings, and dietary supplements—this is the fundamental reason for BHT's enduring popularity in the food industry.