Antioxidants arylamine

Carcinogenic aminoazo dyes were previously found to increase the latent period of linoleate peroxidation and that DAB was a more effective antioxidant than MAB (13). Furthermore, as autoxidation of the linoleic acid proceeded, N-demethylation of DAB and MAB occurred. Demethylation of DAB also occurred in vitro when DAB is dissolved in cottonseed oil and mixed with ground brown rice (14). Our results clearly indicate that a linoleic acid hydroperoxide-hematin system readily N-demethylates DAB to MAB and MAB to AB. Previously, it was found that in this system, HCHO formation by N-demethylation of DAB was faster than that obtained with MAB (15). Similar results are now reported during the H202 peroxidase catalyzed oxidation of DAB and MAB. Peroxidase and H2O2 have previously been reported to catalyze the N-dealkylation of other arylamines (16, 17). 

Yao, J. 1997. Evaluation of Sodium Acetylacetonate as a Synergist for Arylamine Antioxidants in Synthetic Lubricants. Tribol. Int., 30,795-799. 

Arylamines act as primary antioxidants by donating hydrogen. They are highly effective because they act both as chain terminators and peroxide decomposers. Negative properties include their tendency to discolour and stain and their toxicity, which precludes their application in non-pigmented plastics and those intended for food use. Arylamines are included in black wire and cable insulation and polyurethanes. 

The most widely used CB antioxidants are the polymer soluble 2,6-di-tert-butylphenols, such as BHT and 1076, in plastics and the arylamine antioxidants, e.g. PBN and IPPD, in rubbers ... 

Phenols are less effective antioxidants than the arylamines but they are non-discolouring. They are converted into a variety of oxidation products e.g. quinones and stable phenoxyl radicals) by further reaction with oxygen or peroxyl radicals (page 64). Many of these are themselves antioxidants. 

Amines. Amines, normally arylamines, function as primary antioxidants by donating hydrogen. Amines are the most effective type of primary antioxidant, having the ability to act as chain terminators and peroxide decomposers. However, they tend to discolor, causing staining, and, for the most part, lack FDA approval. For this reason, amines are found in pigmented plastics in nonfood applications. Amines are com-... 

The antioxidants presently used in the practice of reprocessing polymer materials mainly represent derivatives of the following classes of compounds phenols, sulfide phenols, and arylamines, as well as phosphorous acid esters (phosphites). 

The first acts by removing the active free radicals which are involved in the cyclical chain reaction described in (1). Normally the alkylperoxy radical (ROO-) is the reaction species present in highest concentration and this reacts readily with phenolic and arylamine antioxidants (AH) to give a new stable free radical species which cannot continue the chemical chain reaction (2a). The absorption of oxygen and the rapid formation of hydroperoxide is therefore slowed down ... 

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