Anti-oxygen

An anti-oxygen such as catechol or hydroquinone is used to prevent polymerization. Hydroquinone should be added in the ratio of one part per thousand unless the phenylethylene is to be used immediately.1... 

One can see that the substance a acts as a negative catalyst (inhibitor) and that it disappears during its action. Such anticatalytic effects were studied in the renowned works by Moureau and Dufraisse on anti-oxygenes from about 1920 (17). They also found that the inhibiting effect on the autoxidation of certain aldehydes by certain substances, e.g., quinols, disappeared after a while. Some years later Backstrom (18) and co-workers showed by chemical analysis that the inhibitors were in such cases actually used up (oxidized) during their action. 

Li GR, Wu JJ, Jin WJ, Xie JW. Anti-oxygen-quenching room temperature phosphorescence stabilized by deoxycholate aggregate. Talanta 2003 60 555-62. 

Doan, F., Miller, G., 1940. Tiypsin-an anti-oxygen for milk. Milk Plant Monthly 29, 42—47. 

In a synthetic medium, SO2 has been shown to take several days to consume 8.0-8.6 mg of oxygen per liter (this amount corresponds with the saturation of this medium). Such oxidation requires the presence of catalyzers, notably iron and copper ions. Yet musts are very oxidizable and should therefore be rapidly and effectively protected against oxidation. Sulfiting accomplishes this. Sulfur dioxide, however, cannot act by its anti-oxygen effect, that is to say by combining with oxygen which is no longer available for the oxidation of other must constituents. 

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