Laboratory Methods of Organic Chemistry - Sciencemadness Dot Org

EXTKACTION APPAEATUS 35
The extraction apparatus is used chiefly for dissolving out
sparingly soluble constituents from mixtures, and for isolating
natural products from (dry) vegetable or animal material. Occasionally
it is very useful for " recrystallising " sparingly soluble
substances from the extraction thimble by means of an appropriate
solvent (especially ether). As a rule, crystals of the dissolved
material separate already from the solution in the flask during the
process of extraction. This solution soon becomes supersaturated
even while hot.
L
FIG. 25 FIG. 26 FIG. 27
When solvents of high boiling point are used the extraction
thimble is directly suspended by a thin wire in the round-botomed
flask, but should not dip into the liquid.
WORKING WITH COMPRESSED GASES
Nowadays every university laboratory is doubtless supplied with
steel cylinders in which the most important gases in common use are
stored in the compresed state.
These gases are :
(1) Oxygen, hydrogen, nitrogen.
(2) Carbon dioxide, chlorine, ammonia, sulphur dioxide.