Diketene

[674-82-8] C4H4O2 (MW 84.07) InChI = 1S/C4H4O2/c1-3-2-4(5)6-3/h1-2H2 InChIKey = WASQWSOJHCZDFK-UHFFFAOYSA-N (acetoacetylation reagent; acetylketene equivalent for heterocyclic synthesis) Alternate Name: 4-methyleneoxetan-2-one. Physical Data: mp −7.5 °C; bp 69–70 °C/100 mmHg; d 1.090 g cm−3. Solubility: sol most organic solvents; immiscible H2O, hexane. Form Supplied in: neat liquid. Analysis of Reagent Purity: IR (2150 cm−1), NMR. Preparative Method: via dimerization of ketene.2 Purification: vacuum distillation. Handling, Storage, and Precautions: lachrymator; best stored as a solid (refrigerated) in plastic containers; avoid contamination; prepare for exothermic reactions. Handle in a fume hood.