The Collaborative International Dictionary of English v.0.48:

Phlogisticate \Phlo*gis"ti*cate\, v. t. [imp. & p. p.
   Phlogisticated; p. pr. & vb. n. Phlogisticating.] (Old
   Chem.)
   To combine phlogiston with; -- usually in the form and sense
   of the p. p. or the adj.; as, highly phlogisticated
   substances.
   [1913 Webster]