Autoclaves made of stainless steel are indispensable in transition-metal organometallic chemistry for preparing metal carbonyl derivatives
requiring the use of carbon monoxide under pressures sufficiently high to exclude use of Hoke bombs or Carius tubes. [...]
Stainless-steel Hoke bombs (Fig. 10) are particularly suitable for reactions requiring gases conveniently charged from a vacuum system. The
Hoke bomb fittings are also readily adaptable for connection to a high-pressure system for introduction of carbon monoxide under pressure. However, it
must be borne in mind that the maximum safe operating pressure of a Hoke bomb is around 100 atmospheres. This and the difficulty of stirring of
shaking reactions mixtures in Hoke bombs make them less desirable than autoclaves for reactions with carbon monoxide under pressure. The use of Hoke
bombs for simply carrying out reactions with liquids above their boiling points [...] should be pointed out. [...]
The final alternative for pressure reactions is a sealed thick-walled glass Carius tube (Fig. 11). The maximum safe working pressure for a
Carius tube depends on the skill of the operator in sealing the tube but in any case it is less than that of a Hoke bomb. Explosions are therefore
more frequent when using Carius tubes than when using Hoke bombs. [...] An obvious advantage of Carius tubes over Hoke bombs is the ability to observe
the reaction mixture while the reaction is taking place. |
