THERMOCHEMICAL BEHAVIOR OF LANTHANUM COMPLEXES OF 2-ETHYLHEXYL PHOSPHORIC-ACID

The thermochemical behaviour of solid-state complexes of lanthanum wit h mono-(2-ethylhexyl) phosphoric acid (H2B) (La(HB)(3) . 1.5H(2)O and La2B3 . H2O) was studied. The thermal decomposition of these complexes proceeds without melting to yield La(PO3)(3) and a mixture of La(PO3) (3) and LaPO4, respectively La(HB)(3) . 1.5H(2)O decomposes via dehydr ation (323-383 K), condensation of the OH-groups with formation of a d iphosphate structure (383-458 K) and a stepwise degradation of the hyd rocarbon chains (443-565 K). The dehydration of La2B3 . 3H(2)O (333-43 3 K) is followed by decomposition of the hydrocarbon group. From a com bination of the present results with previous data [1], it was conclud ed that the temperatures and mechanisms of the decomposition of the hy drocarbon part of the lanthanide complexes of (2-ethylhexyl) phosphori c acids depend on the nature of the lanthanide, the atmosphere, and th e structure of the complexes.