Methylethyl ketone oxime is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

with the formula C₂H₅C(NOH)CH₃. This colourless liquid is the

oxime In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted ...

derivative of methyl ethyl ketone. MEKO, as it is called in the paint industry, is used to suppress "skinning" of paints: the formation of a skin on paint before it is used. It is particularly used in

alkyd An alkyd is a polyester resin modified by the addition of fatty acids and other components. Alkyds are derived from polyols and organic acids including dicarboxylic acids or carboxylic acid anhydride and triglyceride oils. The term ''alkyd'' is a m ...

paints. MEKO functions by binding the drying agents, metal salts that catalyze the oxidative crosslinking of

drying oil A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (not ...

s. Once the paint is applied to a surface, MEKO evaporates, thereby allowing the drying process to proceed. Other antiskinning agents have been used, including phenolic

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...

s (E.G

butylated hydroxytoluene Butylated hydroxytoluene (BHT), also known as dibutylhydroxytoluene, is a lipophilic organic compound, chemically a derivative of phenol, that is useful for its antioxidant properties. BHT is widely used to prevent free radical-mediated oxidat ...

), but these tend to yellow the paint.J. Bielman "Antiskinning Agents" in "Additives for Coatings" J. H. Bielman, Ed. Wiley-VCH, 2000, Weinheim. . This oxime is also used in some types of RTV silicones.

References

{{Reflist Ketoximes Visual arts materials Painting materials