Prelab Questions recrystallization 2 Give four 4 requirement

Prelab Questions recrystallization? 2. Give four (4) requirements for selecting an extracting solvent.

Solution

1. Both extraction and recrystallization are separation techniques.

In extraction method, one of the components has greater solubility in the extraction fluid such as aromatic compounds are more soluble in phenol.

In recrystallization method, when the temperature is reduced one the components gets crystallized such as removal of waxes from oil by cooling.

2. Requirements for selecting solvent

(i) Solubility : The solvent should have low solubility in the feed solution, otherwise the separation is not clean.

(ii)Chemical reactivity : The solvent should be chemically stable and inert toward the components.

(iii)Recoveribility : The solvent should be recoverable for re-use.

(iv) Availability and cost : The solvent should be commercially available and less costly.