ジケテン

解説

ジケテン，放置すると徐々に重合するため，安定剤を含んだ形で販売されることもある．550 ℃ 程度で熱分解するとアセチル化剤などとして有用なケテンを生成する．また，さまざまな求核体(アルコール，アミンなど)と反応し，アセト酢酸誘導体を生成する．この性質を利用してアミノ基などの保護基として用いられることもある．求電子体とはエキソメチレン部で反応し，4位に置換基をもつアセトアセチル誘導体を与える．LD50 560 mg/kg(ラット，経口)．

森北出版「化学辞典（第2版）

用途

医薬、染料、防腐剤原料

応用

薬品，染料，農薬，高分子などの分野で広範に使われている．

使用

Diketene is used as a reactant in the manufacture of paper and control of its sizing. In addition its used in the preparation of potent and selective inhibitor of histone methyltransferase EZH2 in the treatment of B-Cell lymphomas.

一般的な説明

A colorless liquid with a disagreeable odor. Slightly less dense than water. Flash point 90°F. Irritates skin and eyes. Used to make paints and pharmaceuticals.

空気と水の反応

Highly flammable. Slightly soluble in water.

反応プロフィール

DIKETENE is a very reactive dimer, Acetyl ketene may undergo a spontaneous decomposition followed by explosion or ignition [Vervalin, 1973, p.86]. In the presence of bases, amines, mineral acids or Lewis acids a violent polymerization will occur, accompanied by gas evolution [Zdenek, F. et al., Czech Pat. 156 584, 1975].

健康ハザード

TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.

火災危険

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. May polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Solubility in organics

Diketene is miscible with acetic anhydride, with many ketones and esters (e.g., acetone, methyl acetate, ethyl acetate, butyl acetate) with diethyl ether, tetrahydrofuran, chlorinated hydrocarbons, acetonitrile, and toluene. Furthermore, contrary to most literature reports, it is slightly soluble in aliphatic hydrocarbons such as hexane (ca. 12.5 wt % at 23℃), octane, cyclohexane, and methylcyclohexane. It is very slightly soluble in water, in which it decomposes slowly.