The Collaborative International Dictionary of English v.0.48:

Hydrogenate \Hy"dro*gen*ate\, v. t. [imp. & p. p.
   Hydrogenated; p. pr. & vb. n. Hydrogenating.] (Chem.)
   To hydrogenize.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hydrogenate
    v 1: combine or treat with or expose to hydrogen; add hydrogen
         to the molecule of (an unsaturated organic compound) [ant:
         dehydrogenate]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "hydrogenate":
   acetify, acidify, acidulate, aerate, aerify, alkalify, alkalize,
   atomize, borate, carbonate, catalyze, chemical, chlorinate,
   distill, electrolyze, emit, etherify, etherize, evaporate, exhale,
   ferment, fluidize, fractionate, fume, fumigate, gasify, give off,
   homopolymerize, hydrate, hydroxylate, isomerize, nitrate, oxidize,
   oxygenate, pepsinate, perfume, peroxidize, phosphatize, polymerize,
   reduce, reek, send out, smoke, spray, steam, sublimate, sublime,
   sulfate, sulfatize, sulfonate, vaporize, volatilize, work