A solubility and thermoanalytical study of alkali and alkaline earth solid complexes of pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid, H4L) is reported. The insoluble Na+ species is Na2LH2. K+, Rb+ and Cs+ form MLH3. The stoichiometry of precipitation of H4L with Ca2+, Ba2+ and Sr2+ depends on pH: at pH < 4, MLH2 is formed; in the range 4 < pH < 4.5, we found a mixture of MLH2 and M2L; and at pH > 4.5, only M2L is formed. The pK(s0) of all the species were determined. The insoluble compounds were also characterized by thermogravimetric analysis.
STUDIES ON POLYFUNCTIONAL O-LIGANDS - SOLUBILITY AND THERMAL-STABILITY OF 1,2,4,5-BENZENETETRACARBOXYLATE COMPLEXES WITH ALKALI AND ALKALINE-EARTH METAL-IONS / Curini, Roberta; D'Ascenzo, Giuseppe; DE ROBERTIS, A; DE STEFANO, C; Sammartano, S.. - In: THERMOCHIMICA ACTA. - ISSN 0040-6031. - STAMPA. - 173:(1990), pp. 25-41. [10.1016/0040-6031(90)80586-N]
STUDIES ON POLYFUNCTIONAL O-LIGANDS - SOLUBILITY AND THERMAL-STABILITY OF 1,2,4,5-BENZENETETRACARBOXYLATE COMPLEXES WITH ALKALI AND ALKALINE-EARTH METAL-IONS
CURINI, Roberta;D'ASCENZO, Giuseppe;
1990
Abstract
A solubility and thermoanalytical study of alkali and alkaline earth solid complexes of pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid, H4L) is reported. The insoluble Na+ species is Na2LH2. K+, Rb+ and Cs+ form MLH3. The stoichiometry of precipitation of H4L with Ca2+, Ba2+ and Sr2+ depends on pH: at pH < 4, MLH2 is formed; in the range 4 < pH < 4.5, we found a mixture of MLH2 and M2L; and at pH > 4.5, only M2L is formed. The pK(s0) of all the species were determined. The insoluble compounds were also characterized by thermogravimetric analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
