ジヨードメタン 化学特性,用途語,生産方法
外観
わずかにうすい黄色〜黄褐色, 澄明の液体
溶解性
アセトン及びエタノールに溶けやすく、水にほとんど溶けない。
解説
ジヨードメタンCH2I2(267.84).ヨウ化メチレンともいう.ヨードホルムを亜ヒ酸ナトリウムあるいはヨウ化水素で還元すると得られる.黄色の液体.融点6 ℃,沸点181 ℃.d1515"3.3326.nD15"1.7425.エタノール,エーテルに易溶.水銀についで比重の大きな液体である.鉱物の浮遊選鉱や無機化合物の比重測定に利用される.[CAS 75-11-6]
森北出版「化学辞典(第2版)
用途
有機合成原料。重い比重を利用した無機物の分離。
用途
比重が大きいことから無機化合物の比重の測定または分離に用いられる。しかし毒性を持つ可能性から、より安全な化合物に替えることが望ましいとされる。また、シモンズ?スミス反応のような有機合成反応の試薬として用いられる。
使用上の注意
不活性ガス封入
説明
Diiodomethane (CH2I2) is an iodine containing organic compound. Its decomposition in acetonitrile initiated by 310nm light has been investigated. Femtosecond pump-probe spectroscopic and ab initio molecular dynamics simulations studies of the photodecomposition of CH2I2 suggest the formation of the isomer of diiodomethane (CH2I-I) as hot photoproduct. In the atmosphere, it undergoes photolysis in the presence of ozone to afford iodine oxide (IO) which results in the formation of aerosols. Its vacuum ultraviolet (VUV) photoabsorption spectrum has been reported.
Diiodomethane has been used as a probe liquid for evaluation of the polar and dispersive components of the surface energy of the catecholamine coated fiber surfaces. It may be used for the preparation of cyclopropyl ketones, esters and amides.
Diiodomethane may be used as a probe solvent in contact angle measurement to analyze the hydrophilicity of polymer surfaces.
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化学的特性
Diiodomethane is a light yellow or gold liquid with chloroform-like odour. It has a relative density of 3.325 at 20°C and can be mixed with benzene to produce liquids with different densities. These mixtures are used in the determination of the refractive indices of minerals and for the separation of minerals according to density.
使用
Diiodomethane is used to determine the density of minerals and other solid samples due to its high density. It is used as an optical contact liquid to determine the refractive index of certain gemstones. In simmons-smith reaction, it acts as a reagent to generate methylene (carbine) free radical. It reacts with olefins to prepare cyclopropanes with high stereo specificity.
主な応用
Diiodomethane is used as the dispersive (non-polar) liquid while de-ionized water and glycerol as polar liquids. It is also used in separating mixtures of minerals. In determining the specific gravity of minerals and other substances. In the manufacture of x-ray contrast media.
一般的な説明
Diiodomethane (CH
2I
2) is an iodine containing organic compound. Its decomposition in acetonitrile initiated by 310nm light has been investigated. Femtosecond pump-probe spectroscopic and ab initio molecular dynamics simulations studies of the photodecomposition of CH
2I
2 suggest the formation of the isomer of diiodomethane (CH
2I-I) as hot photoproduct. In the atmosphere, it undergoes photolysis in the presence of ozone to afford iodine oxide (IO) which results in the formation of aerosols. Its vacuum ultraviolet (VUV) photoabsorption spectrum has been reported.
危険性
May be irritating and narcotic.
Diiodomethane has the advantages of high opacity,ease of penetration,and ease of removal because it evaporates fairly quickly.However,it can cause skin burns.
合成
Diiodomethane can be prepared from the widely available solvent dichloromethane by the action of sodium iodide in acetone in the Finkelstein reaction:
CH2Cl2 + 2 NaI → CH2I2 + 2 NaCl.
It can also be prepared by reducing iodoform with elemental phosphorus or sodium arsenite:
CHI3 + Na3AsO3 + NaOH → CH2I2 + NaI + Na3AsO.
Diiodomethane is prepared by reacting iodoform with sodium acetate in ethanol.
合成方法
ヨードホルムを亜ヒ酸ナトリウムまたはヨウ化水素で還元するか,ジクロロメタンをヨウ化ナトリウム水溶液でヨウ素化して得られる
純化方法
Fractionally distil it under reduced pressure, then fractionally crystallise it by partial freezing, and stabilize it with silver wool if necessary. It has also been purified by drying over CaCl2 and fractionally distilling from Cu powder. Store it in the dark. [Beilstein 1 IV 97.]
ジヨードメタン 上流と下流の製品情報
原材料
準備製品