title: Solubility and thermal stability of some amino-mellitate compounds.
abstract: By reaction between the anion of mellitic acid (benzenehexacarboxylic acid) and some protonated linear polyamines (diethylenetriamine, triethylenetetramine, tetraethylene-pentamine, pentaethylenehexamine, spermidine, and spermine), fairly insoluble complexes have been obtained, with the general formula (amine)(x)(mellitate)H(6) (diethylenetriamine and spermidine, x=1; triethylenetetramine and spermine, x=0.75; tetraethylenepentamine, x=0.6 and 0.8; pentaethylenehexamine, x=0.5). K(s0) values for these complexes have been determined at I=0 mol dm(-3) and T=25 degrees C (logK(s0) ranges between -48.2 and -56.6). The solubility has been studied as a function of pH and of ionic strength. The thermal analysis, performed using air or argon flow, showed that all the solids behave in a similar way. In the range 20-120 degrees C the loss of hydration water occurs, and in the range 150-350 degrees C the first step of non oxidative decomposition takes place, with complete decomposition at 650 degrees C in air flow, whilst in argon flow the decomposition is still incomplete at 900 degrees C. Preliminary results of a parallel diffractometric study are also reported.
authors.affiliation: Dipartimento di Chimica, Università "La Sapienza", Piazzale A. Moro, I-00100 Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Curini
authors.forename: A
authors.initials: A
authors.lastname: De Robertis
authors.forename: C
authors.initials: C
authors.lastname: Foti
authors.forename: S
authors.initials: S
authors.lastname: Materazzi
authors.forename: M A
authors.initials: MA
authors.lastname: Orrù