Multimodal porous zirconium silicate macrospheres: Synthesis, characterization and application as catalyst in the ring opening reaction of epichlorohydrin with acrylic acid

Hierarchical zirconium silicate macrospheres with diameters in the range 1.7 divided by 1.8 mm were synthesized by spray gelling technique using a multi-templating method. Inexpensive, environmentally benign and easily accessible natural resources (yeast, gelatin, agar and chitosan) were used as templating agents. These materials were characterized by different complementary techniques: XRD, XPS, EDAX/SEM, FTIR and N-2 porosimetry. Infrared spectra of the adsorbed pyridine were used to investigate the type of the acid sites existing in the samples. Spherical zirconium silicate beads were tested as catalysts in the addition reaction of acrylic acid to epichlorohydrin. In order to evaluate the catalyst lifetime the zirconium silicate macrospheres were reused 10 times. No loss of the catalytic activity and no attrition of the macrospheres were noticed in these runs which prove that the zirconium silicate beads behave as an efficient and stable heterogeneous catalyst.