SYNTHESIS AND CHARACTERIZATION OF 2 GALLIOPHOSPHATES WITH OCCLUDED METHYLAMINE

Two novel framework galliophosphates have been synthesized from ethylene glycol solvent in the presence of a template, methylamine, by varying the content of the amine in reaction mixtures. The X-ray powder diffraction pattern of one crystalline phase is indexable on the basis of an orthorhombic cell having a = 16.2818+/-0.0018 angstrom, b = 9.7343+/-0.0013 angstrom and c = 8.8040+/-0.0013 angstrom; the other has an orthorhombic cell with a 10.2500+/-0.0019 angstrom, b = 14.1107+/-0.0014 angstrom and c = 16.9308+/-0.0027 angstrom. Chemical analysis, combined with experimental density and indexed X-ray powder diffraction data, discloses their idealized formulae to be Ga3P3O12(CH3NH2)2(H2O) with Z = 4 and D = 2.73 g cm-3, and Ga3P3O12(CH3NH2)(H2O) with Z = 8 and D = 2.94 g cm-3, respectively. Ga3P3O12(CH3NH2)(H2O) has poor thermal stability; loss of methylamine and water destroys its framework structure. However, the Ga3P3O12(CH3NH2)2(H2O) precursor is converted into the molecular sieve GaPO4-25 upon calcination above 280-degrees-C.