Comparison of D,L-mandelic acid resolution on zeolite and silica supportedpirkle-type chiral stationary phases

Zeolite A, a material of crystalline character, and Hypersil silica have be en used as support for the preparation of chiral stationary phases. On the amorphous silica support surface the silanol groups are randomly dispersed. The crystalline zeolite secondary building units consisting primarily of S iO4, AlO4- tetrahedra determine the regularity of surface silanol groups. O wing to the crystal lattice structure, the location of silanols is well det ermined and hence the dispersion of chiral selector molecules chemically bo nded onto the zeolite surface silanol groups is fundamentally arranged. Ami des of DNB-L-Leu, DNB-L-Phe, B-L-Leu chiral selector molecules were anchore d onto the zeolite silanols and B-L-Leu onto the silica support silanols. L ipophilic buffer in RP conditions has dynamically modified the residual sil anols of each support. The enantioseparation of ion paired D,L-mandelic aci d from aqueous solution on the zeolite and silica supported chiral stationa ry phases prove a superior enantioseparation on the zeolite supported phase s.