Tert-butyl hydroquinone, also known as tert-butyl hydroquinone, referred to as TBHQ, has a molecular formula of C 10 H 14 O 2 and a relative molecular mass of 166.22. Tert-butyl hydroquinone is a white powdery crystal with a special odor, a melting point of 126.5~128.5, and a boiling point of 300 degrees Celsius. Soluble in ethanol and ether, soluble in oil, insoluble in water. It is stable to heat and does not form colored substances in the presence of iron and copper ions, but can be pink when exposed to light or alkaline conditions.

Basic Information

Chinese name: tert-butyl hydroquinone

English name: tert-Butylhydroquinone

Alias: tert-butyl hydroquinone; TBHQ; tert- butyl hydroquinone ; tert-butyl hydroquinone;

Molecular formula: C 10 H 14 O 2

Molecular weight: 166.22

CAS NO．：1948-33-0

Preparation method: It is prepared by the interaction of hydroquinone and tert-butanol.

Toxicological basis:

①LD50: Oral 0.7~1.0g/kg for rats.

②ADI：0~50.2mg/kg（bw）（FAO/WHO，1994）

Quality Requirements: Quality Standards (FAO/WHO, 1995)

Content/% ≥ 99.0

tert-butyl-p-benzoquinone /% ≤ 0.2

2,5-Di-tert-butylhydroquinone/% ≤ 0.2

Hydroquinone/% ≤ 0.1

Toluene (mg/kg)/% ≤ 25

Heavy metals (as Pb) (mg/kg) ≤ 10

Arsenic (as As) (mg/kg) ≤ 3

performance

Tertiary butyl hydroquinone has strong antioxidant capacity. For vegetable oils, the order of antioxidant capacity is TBHQ>PG>BHT>BHA; for animal oils, the order of antioxidant capacity is TBHQ>PG>BHA>BHT.

TBHQ has no effect on stabilizing the color and odor of oils, it has no "carry-in" ability in baked goods, this property can be improved when mixed with BHA, but it has this ability in fried foods.

TBHQ has a synergistic effect on other antioxidants and chelating agents, and it is still effective in oils where other phenols do not work. The addition of citric acid enhanced its antioxidant activity. In vegetable oils, bulk oils, and animal fats, TBHQ is typically used in combination with citric acid.

In addition to anti-oxidative effects, TBHQ also has a certain bacteriostatic effect. The minimum inhibitory concentration for bacteria and yeast is 0.005%~0.01%, and for mold is 0.005%~0.028%. NaCl has a synergistic effect on its antibacterial effect

Manufacturing method and quality index

There are two preparation methods for tert-butyl hydroquinone. One is to use the same amount of hydroquinone and tert-butyl alcohol as the solvent, 85% sulfuric acid as the catalyst, and react at 90~100 ℃. After that, the hot toluene layer was separated, the solvent was removed by distillation, the isomer was removed by hot filtration, and the filtrate was cooled to obtain TBHQ. Another method is to use the same amount of hydroquinone and isobutylene under the catalysis of 85% phosphoric acid, and use toluene as a solvent to react at 105 ° C, separate the toluene layer and cool it to obtain TBHQ containing a small amount of impurities. The product can be obtained by recrystallization with hot water

safety term

S26：In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

After accidental contact with eyes, rinse immediately with plenty of water and seek medical advice.

risk term

R22：Harmful if swallowed.

Harmful if swallowed.

Usage and Precautions

Fat-soluble antioxidant

my country's "Hygienic Standard for the Use of Food Additives" (GB2760-1996) stipulates that tert-butyl hydroquinone can be used in edible oils and fats, fried foods, dried fish products, biscuits, instant noodles, quick-cooked rice, canned dried fruits, and cured meat products. , The maximum usage is 0.2g/kg. For other references, for example, Taiwan Province, China's "Scope of Use and Dosage Standard for Food Additives" (1986) stipulates that tert-butyl hydroquinone can be used in oils and butters, and the limit of use is below 0.2g/kg.

tert-Butylhydroquinone is a fat-soluble antioxidant

Poor heat resistance, not suitable for frying and baking conditions, can be used together with butylated hydroxyanisole to improve. It has better storage effect on vegetable oils and fats at room temperature. In addition, tert-butyl hydroquinone has a certain antibacterial effect, especially when combined with salt in a slightly acidic medium. Tertiary butyl hydroquinone has a synergistic effect on other antioxidants and chelating agents, and the addition of citric acid can enhance its antioxidant activity. In vegetable oils, leavening oils, and animal oils, tert-butylhydroquinone is typically used in combination with citric acid. When determining the oxidative stability of lard by the method of active oxygen, the effect of tert-butyl hydroquinone is equal to that of butylated hydroxyanisole, more than that of dibutylated hydroxytoluene and propyl gallate . Incorporating it into packaging materials can effectively inhibit the oxidative deterioration of lard. For poultry fat, tert-butyl hydroquinone is more effective than butylated hydroxyanisole, dibutylhydroxytoluene or propyl gallate.

tert-butylhydroquinone for most oils

Especially effective with vegetable oils. The effect on various crude and refined oils is equal to or exceeds that of butylated hydroxyanisole, dibutylated hydroxytoluene, and propyl gallate. Especially effective in cottonseed oil, soybean oil and safflower oil. Used in combination with citric acid and ascorbyl palmitate, tert-butyl hydroquinone has a high antioxidant effect on soybean oil and the mixed oil composed of 50% soybean oil and 50% cottonseed oil, and has a high anti-oxidative effect on refining, decolorization, removal of The smelly olive oleate worked better than propyl gallate, butylated hydroxyanisole, and dibutylated hydroxytoluene. For meat products, tert-butyl hydroquinone is effective in prolonging the time for frozen patties to develop a rancid smell. Identification method: Dissolve about 5mL of this product in 10Ml methanol, add a few drops of dimethylamine solution (25g/100mL), it should appear red to pink. Content analysis: Accurately weigh 0.2 g of the crushed sample, dissolve it in 10 mL of methanol, and add 150 mL of distilled water and 1 mL of sulfuric acid (1 mol/L). Using sodium p-benzidine sulfonate solution (3g/L) as indicator, titrate from yellow to red-purple with 0.1mol/L cerium sulfate standard solution. Do blank experiments in the same way. The content of 0.1 mol/L cerium sulfate standard solution per milliliter is equivalent to 8.311 mg of tert-butyl hydroquinone.