The Collaborative International Dictionary of English v.0.48:

Dephlegmate \De*phleg"mate\, v. t. [imp. & p. p. Dephlegmated;
   p. pr. & vb. n. Dephlegmating.] [See Dephlegm.] (Chem.)
   To deprive of superabundant water, as by evaporation or
   distillation; to clear of aqueous matter; to rectify; -- used
   of spirits and acids.
   [1913 Webster]