Editing Gasoline (section)

===Fuel stabilizers (antioxidants and metal deactivators)===
[[File:Antioxidant.png|thumb|Substituted [[phenol]]s and derivatives of [[phenylenediamine]] are common antioxidants used to inhibit gum formation in gasoline]]
Gummy, sticky resin deposits result from [[Oxidation|oxidative]] degradation of gasoline during long-term storage. These harmful deposits arise from the oxidation of [[alkene]]s and other minor components in gasoline{{citation needed|date=March 2024}} (see [[drying oil]]s). Improvements in refinery techniques have generally reduced the susceptibility of gasolines to these problems. Previously, catalytically or thermally cracked gasolines were most susceptible to oxidation. The formation of gums is accelerated by copper salts, which can be neutralized by additives called [[metal deactivator]]s.

This degradation can be prevented through the addition of 5–100 ppm of [[antioxidant]]s, such as [[phenylenediamine]]s and other [[amine]]s.<ref name="Ullmann2" /> Hydrocarbons with a [[bromine number]] of 10 or above can be protected with the combination of unhindered or partially hindered [[phenol]]s and oil-soluble strong amine bases, such as hindered phenols. "Stale" gasoline can be detected by a [[colorimetric]] [[enzymatic]] test for [[organic peroxide]]s produced by oxidation of the gasoline.<ref>{{patent|AU|2000/72399 A1|Gasoline test kit}}</ref><!---See http://www.patentlens.net/patentlens/structured.cgi?patnum=AU_2000/72399_A1#show if template link fails--->

Gasolines are also treated with [[metal deactivator]]s, which are compounds that sequester (deactivate) metal salts that otherwise accelerate the formation of gummy residues. The metal impurities might arise from the engine itself or as contaminants in the fuel.