The Collaborative International Dictionary of English v.0.48:

Alkalize \Al"ka*lize\ ([a^]l"k[.a]*l[imac]z), v. t. [imp. & p.
   p. Alkalized ([a^]l"k[.a]*l[imac]zd); p. pr. & vb. n.
   Alkalizing ([a^]l"k[.a]*l[imac]`z[i^]ng).] [Cf. F.
   alcaliser.]
   To render alkaline; to communicate the properties of an
   alkali to.
   [1913 Webster] Alkaloid

WordNet (r) 3.0 (2006):

alkalize
    v 1: turn basic and less acidic; "the solution alkalized" [syn:
         alkalize, alkalise, alkalify, basify] [ant:
         acetify, acidify]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "alkalize":
   acetify, acidify, acidulate, alkalify, borate, carbonate, catalyze,
   chemical, chlorinate, electrolyze, ferment, homopolymerize,
   hydrate, hydrogenate, hydroxylate, isomerize, nitrate, oxidize,
   pepsinate, peroxidize, phosphatize, polymerize, reduce, sulfate,
   sulfatize, sulfonate, work