丁烯酮（MVK），结构式CH₃COCH＝CH₂。是最简单的α,β-不饱和酮。

无色具有刺激性臭味的挥发性液体。可燃。易溶于水、甲醇、乙醇、乙醚、丙酮、冰醋酸，微溶于烃。与水形成二元共沸物，共沸点75°C（101.3kPa），含水12％。有毒，对皮肤、眼、鼻和咽喉粘膜有刺激作用，致视力障碍。可经皮肤吸收中毒，与皮肤接触造成斑痕。蒸气吸入时可引起喘息、支气管炎和肺气肿。

Methyl vinyl ketone (MVK, IUPAC name: butenone) is the organic compound with the formula CH₃C(O)CH=CH₂. It is a reactive compound classified as an enone, in fact the simplest example thereof. It is a colorless, flammable, highly toxic liquid with a pungent odor. It is soluble in water and polar organic solvents. It is a useful intermediate in the synthesis of other compounds.