Also known as methyl isobutyl ketone, 4-methyl-2-pentanone. It is a colorless liquid with pleasant smell. Stable in nature. Slightly soluble in water and miscible with most organic solvents. Vapor forms an explosive mixture with air. It has strong local irritation and toxicity. It is commonly used as solvent (for dissolving tetracycline, pyrethrin and DDT, oil dewaxing, etc.), inorganic salt separating agent, beneficiation agent, adhesive, rubber glue, masking paint and organic synthetic raw materials. It is used as a developing solvent for PMMA in electron beam lithography.