Inert atmosphere methods
During your laboratory work you may need to carry out reactions using
chemicals which are described as air sensitive or moisture sensitive. These
compounds may react with water, oxygen, carbon dioxide and even nitrogen
(e.g. lithium metal). The most sensitive chemicals may require special
apparatus such as glove boxes or vacuum line equipment and you should
consult the appropriate specialist literature (Errington, 1997). On the
other hand, many reactions involving some air-sensitive reagents (e.g.
organolithium compounds or hydride reducing agent) can be done on a small
scale using standard glassware with appropriate modifications. For
simple
apparatus for inert atmosphere reactions, the basic requirements are:
- Inert atmosphere, usually nitrogen or argon, piped into the apparatus.
Nitrogen is the most commonly used inert gas, whereas argon is more
expensive but does have the advantage that it is denser than nitrogen and
is not lost from the apparatus as quickly. The inert atmosphere is
maintained in the apparatus by the use of a 'bubbler' on one
of the outlets from the glassware - all other outlets must be stoppered or
capped with septa.
- Appropriate glassware for the experiment which must be
dry.
- Dry solvents and chemicals.
- Syringe techniques for dispensing and transferring chemicals to the
apparatus).
