抄録
The thermal behavior of various copper cyclo-phosphates, Cu2P4O12·8H2O (P4m), Cu3P6O18·12H2O (P6m2), and Cu4P8O24·18H2O (P8m), was investigated using TG-DTA, HPLC, and X-ray diffraction analysis. P4m decomposed perfectly to ortho-(P1), pyro-(P2), and insoluble highpolyphosphates (Phigh poly) with the elimination of water of crystallization. With an increase in temperature, P1 and P2 condensed to Phigh poly, in part, to cyclo-tetraphosphate. The decomposition of P4m proceeded faster under humid air than dry air. P6m also decomposed to short-chain phosphates and Poligo (n=7-14), further to P1, P2, and Phigh poly. Although the water vapor accelerated the decomposition of P6m, it prevented the formation of cyclo-tetraphosphate. P8m lost the most of water of crystallization to decompose to P1 and P2. The formation of cyclo-tetraphosphate was observed at 300°C. The amount of cyclo-tetraphosphate increased with an increase in temperature. Under a higher water vapor pressure, the decomposition of P8m proceeded rather faster than under a lower one, while the rate of condensation reactions to Phigh poly slower than under the higher one. At 450°C, no difference in the effect of atmosphere on the amounts of cyclo-tetraphosphate and Phigh poly was observed.
