|General Phenolic Antioxidant||Antioxidant 264 is an excellent general type of phenolic
antioxidants with no toxicity, no flammability, no corrosion and
excellent storage stability. It can inhibit and delay the
oxidation-degradation of plastic or rubber and prolong their
|Physicochemical Properties||Physical State: Solid /Crystal|
Appearance: White. It turns yellow in the presence of light and
gradually becomes darker.
Odor: Faint, characteristic odor.
Vapor Pressure: 0.01 mm Hg at 20 ?C
Vapor Density: 7.6
Viscosity: 3.47cSt at 20 ?C
Boiling Point: 265 ?C
Freezing/Melting Point: 70 ?C
Solubility: Insoluble in water and soluble in benzene,
methylbenzene, methanol, methyl ethyl ketone, ethanol, isopropanol,
petroleum ether and flaxseed oil.
Specific Gravity/Density: 1.048
Molecular Formula: C15H24O
Molecular Weight: 220.35
|Applications||BHT is listed under three categories in catalogues and databases,
such as food additive, household product ingredient, industrial
additive, personal care product/cosmetic ingredient, pesticide
ingredient, plastic/Rubber ingredient and
BHT is primarily used as an antioxidant food additive. In the
United States, it is classified as generally recognized as safe
(GRAS) based on a National Cancer Institute study from 1979 in rats
and mice. It is approved for use in the U.S. by the Food and Drug
Administration: For example, 21 CFR § 137.350(a)(4) allows BHT up
to 0.0033% by weight in "enriched rice", while 9 CFR §
381.147(f)(1) allows up to 0.01% in poultry "by fat content". It is
permitted in the European Union under E321. It is forbidden as food
additive in Japan (since 1958), Romania, Sweden, and Australia.
Since the 1970s, BHT has been steadily replaced with butylated
hydroxyanisole (BHA). Some food companies have voluntarily
eliminated BHT from their products. Others like General Mills and
Kellogg's announced in February 2015, following a petition by Vani
Hari, that they were going to phase it out.
BHT is also used as an antioxidant in products such as cosmetics,
pharmaceuticals, rubber, electrical transformer oil (at 0.35%),and
embalming fluid. In the petroleum industry, where BHT is known as
the fuel additive AO-29, it is used in hydraulic fluids, turbine
and gear oils, and jet fuels. BHT is also used to prevent peroxide
formation in diethyl ether and other laboratory chemicals. As
rubber antioxidant, BHT can protect rubber from heat and oxidation
aging as well as control the harm from copper. It is also applied
as stabilizer used on synthesized rubber in the handling and
BHT can be applied by dip-moulding, direct mixing, nebulization and
indirect mixing in alcobolic solution.
Some additive products contain BHT as their primary ingredient,
while others contain the chemical merely as a component of their
formulation, sometimes alongside butylated hydroxyanisole (BHA).
|Synthesis Methods||1.Industrially, BHT is prepared by the reaction of p-cresol
(4-methylphenol) with isobutylene (2-methylpropene) catalyzed by
CH3(C6H4)OH + 2 CH2=C(CH3)2 → ((CH3)3C)2CH3C6H2OH
Isobutene is added in the (98:2) mixture of p-cresol and
concentrated sulfuric acid. The reaction is carried out at 65~70 ℃
for 5h. The acid in the mixture is washed away with water of 60 ℃.
The mixture is then washed with 10% NaOH solution and hot water to
obtain the neutral crude product. The crude product is dissolved in
hot 50% alcohol along with 0.5% of sulfocarbamide. Filtration and
spin-drying is carried out when the liquid is still hot. The
finished product is obtained through the following desiccation. In
this routine, the productivity rate is as high as and the product
purity is with melting point of over 69.5℃.
In industry, the cascading main-vice tower technology is usually
adapted. P-cresol and catalysts are put in the main and vice
towers. The temperature in the main tower is maintained at 65～80℃
while that in the vice tower at 50～70℃. Isobutene gas is pumped in
from the bottom, the majority of which react with p-cresol and the
rest of which is let into the vice tower for further reaction with
p-cresol. The reaction cycle in the main tower lasts for 4～5h. On
the end of the reaction, isobutene gas is cut off and NaOH solution
(20%) is added. Compressed air is pumped in to bubble the solution.
The neutralized crude alkylation product is extracted through
distillation tower with 8 theoretical plates. The crude product is
then dissolved in 95% alcohol and separated from mineral salts
using ion exchange followed by refrigeration crystallization at
10～20℃, separation and vacuum drying to obtain the finished product
with its melting point at over 69℃.
2.In another synthesis routine, p-cresol and tert.-butyl alcohol
are mixed in their molar ratio of 1:1.1. Under the catalysis of
ortho-phosphoric acid, the react is conducted at 65～70℃ with
intense stirring. The product is washed with caustic soda solution
to reach certain basicity and then washed into neutral with water.
The dissolvent is then removed and the product is obtained through
recrystallization with alcohol.
3.Alternatively, BHT is prepared from 2,6-di-tert-butylphenol by
hydroxymethylation or aminomethylation followed by hydrogenolysis.
|Content Analysis||Internal standard solution: Dissolve 500mg of diphenylamine or
4-tert butyl phenol in acetone and dilute with it to 250mL.|
Standard solution :Dissolve 100mg of BHT in acetone and dilute with
it to 50mL.
Determination: Dissolve 100mg of the sample in internal standard
solution and dilute with it to 50mL. The sample solution is put
into a gas chromatograph equipped with a hydrogen flame ion
detector. A column (1.5 m x 3 mm ID) containing 10% XE-60 at 100 to
200 mesh Aeropak 30 is kept at an constant temperature of 155 ° C.
The temperature of the injector and the detector ss 225 ° C and 250
° C, respectively. The determination is conducted with nitrogen
carrier gas whose flow velocity is 30ml/min.
The standard curves are drawn according to the peak height of
various concentrations of BHT and internal standard solution, and
then the reference standard curve is used to determine the content
|Toxicological Information||Routes of Entry:|
Absorbed through skin. Dermal contact. Inhalation. Ingestion.
Toxicity to Animals:
Acute oral toxicity (LD50): 650 mg/kg [Mouse].
- FAO/WHO(1984,mg/kg): 200 in general edible oils and fats, 200 in
butter oil ( not allowed in direct consumption and recombined
milk), 100 in margarine.
- In Japan (g/kg): 0.2 in grease and pickled fishes, 1 in
impregnation liquid for frozen fishes, 0.75 in gum confection.
- USDA (9CFR, §318．7, §381．147,2000%): 0.003 in dry sausage； 0.01 in
refined animal oil； 0.02 in margarine； 0.01 in poultry (calculated
by fat content).
- FDA (21CFR, §172．115, §172．615,§173．340,§181．24, §182．3173；
§172．515；2000,mg/kg) 50 in dehydrated potato and cereal； 0.1% in
defoamer； 0.005％ migrated from packaging material for food； 0.5% in
essential oil； 0.1% in gum base；0.02% in fat food.
- EEC-HACSG:not allowed in infantal food except used for the
supplement of vitamin A.
|Handling and Storage||Precautions for safe handling|
Avoid contact with skin and eyes. Avoid formation of dust and
Provide appropriate exhaust ventilation at places where dust is
Normal measures for preventive fire protection.
Conditions for safe storage
Keep container tightly closed in a dry and well-ventilated
place.Keep in a dry place.
- Suitable extinguishing media
- Use water spray, alcohol-resistant foam, dry chemical or carbon
- Special protective equipment for fire-fighters
- Wear self contained breathing apparatus for fire fighting if
|Chemical Properties||white crystalline solid|
|Uses||Antioxidant 264 as general antioxidants is used widely in polymer
materials, petroleum products and food processing industries.
Antioxidant 264 is commonly used rubber antioxidant, heat, oxygen
aging have some protective effect, but also can inhibit copper
harm. This product does not change color, not pollution.
Antioxidants 264 high solubility in oil, no precipitation, less
volatile, non-toxic and non-corrosive.|
|Definition||ChEBI: A member of the class of phenols that is 4-methylphenol
substituted by tert-butyl groups at positions 2 and 6.|
|Uses||Antioxidant for food, animal feed, petroleum products, synthetic
rubbers, plastics, animal and vegetable oils, soaps. Antiskinning
agent in paints and inks.|
|General Description||White crystalline solid.|
|Air & Water Reactions||Insoluble in water.|
|Reactivity Profile||Phenols, such as 2,6-Di-tert-butyl-4-methylphenol, do not behave as
organic alcohols, as one might guess from the presence of a
hydroxyl (-OH) group in their structure. Instead, they react as
weak organic acids. Phenols and cresols are much weaker as acids
than common carboxylic acids (phenol has Ka = 1.3 x 10^[-10]).
These materials are incompatible with strong reducing substances
such as hydrides, nitrides, alkali metals, and sulfides. Flammable
gas (H2) is often generated, and the heat of the reaction may
ignite the gas. Heat is also generated by the acid-base reaction
between phenols and bases. Such heating may initiate polymerization
of the organic compound. Phenols are sulfonated very readily (for
example, by concentrated sulfuric acid at room temperature). The
reactions generate heat. Phenols are also nitrated very rapidly,
even by dilute nitric acid. Nitrated phenols often explode when
heated. Many of them form metal salts that tend toward detonation
by rather mild shock. May react with oxidizing materials.|
|Fire Hazard||2,6-Di-tert-butyl-4-methylphenol is combustible.|
|Contact allergens||This antioxidant is contained in food, adhesive glues, industrial
oils, and greases, including cutting fluids. Sensitization seems
|Purification Methods||Dissolve BHT in n-hexane at room temperature, then cool with rapid
stirring, to -60o. The precipitate is separated, redissolved in
hexane, and the process is repeated until the mother liquor is no
longer coloured. The final product is stored under N2 at 0o
[Blanchard J Am Chem Soc 82 2014 1960]. It has also been
recrystallised from EtOH, MeOH, *benzene, n-hexane,
methylcyclohexane or pet ether (b 60-80o), and is dried in a
vacuum. [Beilstein 6 IV 3511.]|