二水素ベリリウム

二水素ベリリウム 化学特性,用途語,生産方法

• 説明

  BeH2 was first synthesized in 1951 by reacting dimethylberyllium, Be(CH3)2, with lithium aluminum hydride, LiAlH4. A purer grade of BeH2 can also be formed from the pyrolysis of di-tert-butylberyllium, {Be(C(CH3)3)2} at 210°C. The purest beryllium hydride is obtained by the reaction of triphenylphosphine, i.e. PPh3,with berylliumborohydride,Be(BH4)2 by the reaction:
  Be(BH4)2+2PPh3→2Ph3PBH3 + BeH2
  Note that unlike the other elements in Group IIA where the hydride can be prepared by reaction of the elements, the reaction of the metal with hydrogen to produce beryllium hydride has not proved possible. BeH2 is usually formed as an amorphous white solid, but a hexagonal crystalline form with a higher density (~0.78 g/cm3) has also been reported. This was prepared by heating amorphous BeH2 under pressure, with 0.5–2.5% LiH as a catalyst. A more recent investigation found that crystalline beryllium hydride has a bodycentered orthorhombic unit cell, containing a network of corner-sharing BeH4 tetrahedra (there are 12BeH2 molecules in the unit cell) in contrast to the flat, hydrogen-bridged, infinite chains previously thought to exist in crystalline BeH2. Studies of the amorphous form also find that it consists of a network of cornershared tetrahedra. The density is 0.755 g/cm3.

• 化学的特性

  Beryllium Hydride, BeH2 is an amorphous, colorless, highly toxic polymeric solid (H = 18.3%) that is stable to water but hydrolyzed by acid. It is insoluble in organic solvents but reacts with tertiary amines at 160 °C to form stable adducts, eg, (R3N· BeH2)2. Beryllium hydride was formerly of interest as a rocket fuel and as a moderator for nuclear reactors. Toxicity has been a serious barrier to its commercialization.

• 物理的性質

  White amorphous solid; density 0.65 g/cm³; decomposes at 250°C; reacts with water.

• 使用

  Beryllium hydride (BeH2) liberates hydrogen gas when mixed with water. It is used as a source of hydrogen in experimental rockets and fuel cells. It has also been considered as a moderator for nuclear reactors. Methods of preparing and densifying the pure compound are described in a large number of patents. However, the toxicity has always been a serious barrier to its commercial exploitation.

• 製造方法

  Beryllium hydride is made by treating an ethereal solution of beryllium borohydride with triphenylphosphine, or by pyrolysis of di-tert-butylberyllium.

• Manufacturing Process

  The only known method of producing high purity beryllium hydride (95 – 98 wt % BeH2) is the pyrolysis of di-tert-butylberyllium diethyl etherate in a high boiling hydrocarbon at 200 ℃:
  
  
  

• 安全性プロファイル

  Confirmed carcinogen. Adangerous fire hazard. When heated to 220°C it liberatesexplosive hydrogen gas. Reacts violently with methanol,water, and dilute acids. When heated to decomposition itemits toxic fumes of BeO. See BERYLLIUMCOMPOUNDS and HYDRIDE

二水素ベリリウム 生産企業

Global(3)Suppliers

7787-52-2, 二水素ベリリウム キーワード