Typical antioxidants are alkyl phenols and phenylene diamines. These not only retard the formation of gums and improve storage stability but also diminish the formation of peroxides that may attack rubber hoses used in some aircraft. The dosage is around 20 mg/L.
Besides, minor quantities of metal ions, such as 0.01 ppm copper, picked up by refinery streams may actually catalyse the formation of gums. Metal deactivators are added to chelate these metal traces acting in synergy with the anti-oxidants. Example: N,N-disalicylidene 1,2 propanediamine.
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