Temperature
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Within the limits imposed by the thermal stability of the wanted constituents, a high extraction temperature appears desirable.
TEMPERATURE
Within
the limits imposed by the thermal stability of the wanted constituents, a high
extraction temperature appears desirable. The solubility of most materials
increases as the temperature increases so that higher solute concentrations and
higher concentration gradients are possible. Both this and the increased
dif-fusivity give higher extraction rates. In very many cases, however,
materials are susceptible to heat degradation, and cold extraction must be
used. In addition, the selectivity of a solvent may be impaired at high
temperatures. An example of the use of moderately high temperatures is the
extraction of Rauwolfia alkaloids with boiling methanol.
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