Butylated Hydroxytoluene (BHT)
Antioxidant

The (fat-soluble) crystaline phenolic antioxidant butylated hydroxytoluene (BHT) was patented in 1947 and received approval for use as a food additive and preservative by the U.S. Food and Drug Administration in 1954.(1)

The author of this page does not know how BHT works as an antioxidant. Please consider the page to be a collection of clues.

Here is a microscopic image of BHT crystals.

Microscopic Image of BHT (White Crystalline Powder) Showing Individual Crystals
(Courtesy: Jack Reed, Department of Entomology, Mississippi State University)

Here is a somewhat unorthodox stick figure drawing of a BHT molecule. (In this drawing, some of the sticks really represent sticks. An explanation for this is given further down.)

Stick Diagram and Formula for BHT Molecule

Grey = Carbon; White (and match heads) = Hydrogen; Red = Oxygen

BHT molecules host seven CH₃ methyl groups. A methyl group consists of three hydrogen atoms bonded to a carbon atom which is linked to the remainder of a molecule.(2) In the colored stick diagram, the methyl group hydrogen atoms are shown as match heads to remind readers of their roles as hydrogen donor free radical scavengers. Their anthromorphic motto might be "Light my fire!" (These last two sentences are written by a non-chemist. It may turn out that something else about the molecule causes it's free radical scavenging activity. Input is welcome!)

Structural comparisons of Antioxidants BHA, BHT and Vitamin E

John J. Manura(3) summarizes a gas chromatography/mass spectrometry (GC/MS) study to measure volatile and semi-volatile organics (including BHA and BHT) in food and pharmaceutical packaging. He cites an earlier study(4) focused on quantifying BHA and BHT in food cereals.

Here is a copy of Table 2 in the article from which the two preceding statements were drawn.

Table 2. Antioxidant activity of Berberis vulgaris extracts, BHT and Vitamin E using the Thiobarbituric acid method (TBA).