PRODUCT IDENTIFICATION
H.S. CODE
UN NO.
TOXICITY
CLASSIFICATION
EXTRA NOTES
PHYSICAL AND CHEMICAL PROPERTIES
MELTING POINT
SOLUBILITY IN WATER
REFRACTIVE INDEX
110 C
EXTERNAL LINKS & GENERAL DESCRIPTION
Wikipedia
Linking
Industrial uses:
Antioxidants are frequently added to industrial products. A common use is as
stabilizers in fuels and lubricants to prevent oxidation, and in gasolines to
prevent the polymerization that leads to the formation of engine-fouling
residues. In 2007, the
worldwide market for industrial antioxidants had a total volume of around 0.88
million tons. This created a revenue of circa 3.7 billion US-dollars (2.4
billion Euros). They are widely used to prevent the oxidative degradation of polymers such as rubbers, plastics and adhesives that causes a loss of strength and
flexibility in these materials. Polymers
containing double bonds in their main chains, such as such as
natural rubber and polybutadiene, are especially
susceptible to oxidation and ozonolysis. They can be protected by antiozonants. Solid polymer
products start to crack on exposed surfaces as the material degrades and the
chains break. The mode of cracking varies between oxygen and ozone attack, the former causing a "crazy paving" effect,
while ozone attack produces deeper cracks aligned at right angles to the tensile
strain in the product. Oxidation and UV degradation are also frequently linked,
mainly because UV radiation creates free radicals by bond
breakage. The free radicals then react with oxygen to produce peroxy radicals which
cause yet further damage, often in a chain reaction. Other polymers susceptible to
oxidation include polypropylene and polyethylene. The former is more sensitive owing
to the presence of secondary carbon atoms present in every
repeat unit. Attack occurs at this point because the free radical formed is more
stable than one formed on a primary carbon atom. Oxidation of
polyethylene tends to occur at weak links in the chain, such as branch points in
low density polyethylene.
Local:
Antioxidant is a substance added in small quantities to hydrocarbons which are
susceptible to oxidation, such as rubbers, plastics, foods, and oils to inhibit
or slow oxidative processes, while being itself oxidized. Antioxidants work in
two different ways. In primary antioxidants (also called free-radical
scavengers), antioxidative activity is implemented by the donation of an
electron or hydrogen atom to a radical derivative. These antioxidants are
usually hindered amines (p-Phenylene diamine, trimethyl dihydroquinolines,
alkylated diphenyl amines) or substituted phenolic compounds with one or more
bulky functional groups such as a tertiary butyl at 2,6 position commonly.
Butylated hydroxytoluene (BHT) is a common example of hindered phenolic
antioxidant. The reaction rate, or carbocation stability, in SN1 mechanism is 3° > 2° > 1° > CH3
(no SN1) so, tertiary alkyl moiety exists in lots of phenolic antioxidant
compounds. Primary antioxidants are free radical scavengers which combine with
peroxy radicals and break autocatalytic cycle. In secondary antioxidants ( also
called peroxide decomposers), activity is implemented by the removal of an
oxidative catalyst and the consequent prevention of the initiation of oxidation.
Examples of peroxide decomposer type of antioxidant are trivalent phosphorous
and divalent sulfurcontaining compound such as sulfides, thiodipropionates and
organophosphites. Synergistic effect is expected when primary antioxidants are
used together with secondary antioxidants as primary antioxidants are not very
effective against the degradation by UV oxidation. Sometimes, chelating agents
are added to scavenge metal impurities which can initiate decomposition.
Tert-butyl-Phenol is an intermediate for varnish and lacquer resins, antioxidants, oil field additives, fragrances and stabilizers.
APPEARANCE
99.0% min
REFRACTIVE INDEX