fractionate

verb4

1. •
   To separate (a mixture) into its individual constituents by exploiting differences in some chemical or physical property, such as boiling point, particle size, solubility etc.

   • Crude oil is fractionated in a refinery to produce a number of different petroleum products.
2. •
   To divide a total dose of radiation into fractions.
3. •
   To use the technique of fractionation in hypnosis.
4. •
   To divide each plaintext symbol into several ciphertext symbols as a preliminary stage of encryption.