Stepwise intercalation of piperidine in layered alpha- and gamma- hafnium phosphate

The mechanism of intercalation of piperidine in alpha-hafnium phosphate, Hf (HPO4)(2). H2O (d(002) =7.6 Angstrom) and gamma-hafnium phosphate, Hf(PO4)( H2PO4). 2H(2)O (d(002) = 12.1 Angstrom), has been investigated by the batch method. Saturated phases were not obtained. The reactions take place stepw ise with the final formation of the compounds Hf(HPO4)(2). C5H11N . H2O and Hf(PO4)(H2PO4). C5H11N . 2H(2)O. In the alpha-HfP case, no intermediate ph ases have been detected but in the gamma-HfP case, a new phase, Hf(PO4)(H2P O4). 0.38C(5)H(11)N . 2H(2)O, was isolated. The characterization of the int ercalates was made by chemical and thermal analysis, X-ray diffraction and IR spectroscopy. Materials with a monolaminar arrangement of amine molecule s in the phosphate interlayer region were obtained and the results are comp ared to those described using different intercalation conditions.