マロン酸

解説マロン酸，無色の針状結晶．分解点135 ℃．pK1 2.837，pK2 5.693．水，エタノールに易溶，エーテル，ピリジンに可溶，ベンゼンに難溶．140 ℃ で分解して二酸化炭素と酢酸になる．アミノ酸，そのほかの有機合成にしばしば用いられるほか，酸の一次標準物質としてアルカリ標準液の標定にも用いられる．強い刺激性がある．LD50 1.54 g/kg(ラット，腹腔)．森北出版「化学辞典（第2版）

用途医薬?香料?合成樹脂?接着剤原料

用途有機合成原料、酸の一次標準(アルカリ標準液の標定)、金属イオンのマスキング剤。

説明Malonic acid (MA), also known as propanedioic acid, is a dicarboxylic acid with structure CH2(COOH)2. It have three kinds of crystal forms, of which two are triclinic, and one is monoclinic. That crystallized from ethanol is white triclinic crystals.It decomposes to acetic acid and carbon dioxide at 140℃. It does not decompose at 1.067×103~1.333×103Pa vacuum, but directly sublimates. The ionised form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's ethyl ester. The name originates from Latin malum, meaning apple.

使用Malonic acid is used as an intermediate in the manufacture of barbiturates and other pharmaceuticals. It is a component used as a stabilizer in many high-end cosmetic and pharmaceutical products. Malonic acid is also used as building block in chemical synthesis, specifically to introduce the molecular group -CH2-COOH. It is used for the introduction of an acetic acid moiety under mild conditions by Knoevenagel condensation and subsequent decarboxylation.

一般的な説明White crystals or crystalline powder. Sublimes in vacuum.

使用用途マロン酸はリンゴに含まれていたことから、医療分野などで香料として使用されています。その他、カルボキシ基という官能基を持っていることから、合成樹脂やのような分野で、原料としても使われています。

Malonic acid is usually produced from chloroacetic acid.Reaction: The chloroacetic acid is added to the reaction kettle by adding sodium carbonate aqueous solution to generate sodium chloroacetate aqueous solution, and then 30% sodium cyanide solution is slowly added dropwise, and the reaction is carried out at a predetermined temperature to generate sodium cyanoacetate. After the cyanation reaction is completed, add sodium hydroxide for heating and hydrolysis to generate sodium malonate solution, concentrate, then dropwise add sulfuric acid for acidification to generate malonic acid, filter and dry to obtain the product.This method often does not produce a pure enough product or the pure product has an extremely low yield. Industrially, malonic acid is also produced by hydrolyzing dimethyl malonate or diethyl malonate. This manufacturing method is able to bring about a higher yield and purity, but the organic synthesis of malonic acid through these processes is extremely costly and environmentally hazardous.