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Dtbhq
Antioxidant is a substance added in small quantities to hydrocarbons which are susceptibleto oxidation, such as rubbers, plastics, foods, and oils to inhibit orslow oxidative processes, while being itself oxidized. Antioxidants work in twodifferent ways. In primary antioxidants (also called free-radical scavengers),antioxidative activity is implemented by the donation of an electron or hydrogenatom to a radical derivative. These antioxidants are usually hindered amines (p-Phenylenediamine, trimethyl dihydroquinolines, alkylated diphenyl amines) orsubstituted phenolic compounds with one or more bulky functional groups such asa tertiary butyl at 2,6 position commonly. Butylated hydroxytoluene (BHT) is a commonexample of hindered phenolic antioxidant. The reaction rate, or carbocationstability, in SN1 mechanism is 3 >2 >1 >CH3 (no SN1) so, tertiary alkylmoiety exists in lots of phenolic antioxidant compounds. Primary antioxidantsare free radical scavengers which combine with peroxy radicals and break autocatalyticcycle. In secondary antioxidants ( also called peroxide decomposers), activityis implemented by the removal of an oxidative catalyst and the consequentprevention of the initiation of oxidation. Examples of peroxide decomposer typeof antioxidant are trivalent phosphorous and divalent sulfurcontaining compoundsuch as sulfides, thiodipropionates and organophosphites. Synergistic effect isexpected when primary antioxidants are used together with secondary antioxidantsas primary antioxidants are not very effective against the degradation by UV oxidation.Sometimes, chelating agents are added to scavenge metal impurities whichcan initiate decomposition.DTBHQ is used as an inhibitor, antioxidant, and stabilizer. It is useful as an antioxidantfor rubber products, a stabilizer, and an anti-skinning agent in paints.
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