German:
Antioxidantien
Spanish:
antioxidantes
French:
antioxidants
Italian:
antiossidanti
Russian:
Антиоксиданты
Arabic:
مضادات الأكسدة
Chinese:
抗氧化剂
Japanese:
酸化防止剤
General overview of Antioxidants
Antioxidants inhibit the autoxidation of organic substances by intervening in reactions with free radicals: They reduce or stop the oxidation of other molecules, by hindering reactions with atmospheric oxygen and other chemicals. Living organisms contain antioxidants, such as vitamins C and E. Natural and synthetic antioxidants are added to foods and medications. Regarding industrial applications, antioxidants reduce the oxidative degradation of plastics, elastomers, and adhesives, and additionally serve as stabilizers in fuels and lubricants. They reduce rancidity in oil-based cosmetics, such as lipstick and moisturizers.
The worldwide antioxidant market for industrial applications reached a total volume of 0.88 million tons in 2007, whereby a revenue of approximately 3.7 billion US$ (2.4 billion €) was attained. Although antioxidants are applied in very small amounts, they substantially influence a product's physical parameters, processing, life-span, and in many cases, its profitability. Without the addition of antioxidants, many plastics would not last a particularly long time. Most would actually not even exist, since many plastic articles would not be able to be manufactured without some sort of irreversible damage.
Many different compounds can act as antioxidants. However, only a few classes of chemical compounds with specific structures are actually used as antioxidants on a large scale: phenols, various amines, phosphites, and sulfur compounds. They stop the degradation process in many ways, each according to its structure. An ideal antioxidant system should be able to end the oxidation cycle at every level of degradation.
There is a distinction between primary and secondary antioxidants. Primary antioxidants are also referred to as chain-breaking antioxidants or chain-terminators, because they inhibit chain growth reactions, considering they respond to the proper radicals. The majority of these radical interceptors are either hindered phenols or secondary arylamines. Secondary antioxidants usually contain sulfur and/or phosphorous with a low valency. Their job is to intervene where peroxides or hydroperoxides emerge, and transform them into harmless compounds before they have the capability to form radicals. Accordingly, they are often referred to as hydroperoxide decomposers. Since secondary antioxidants inhibit the formation of radicals, they can also be referred to as preventative antioxidants.
Comprehensive information on antioxidants - their characteristics, application areas, market data, manufacturers, and environmental aspects - can be found in Market Study Antioxidants, from Ceresana Research.
Important antioxidant groups:
Last Revision: 13 Feb 09
