Thermal investigation of some ethylammonium salts in the solid state: Part I

Abstract

Ethylammonium salts of general formula (C 2H 5) n NH 4- n X (where X represents Cl, Br or HSo 4 and n = 1–3) have been synthesised. The purity of the salts was checked by elemental analyses. None of the salts was found to contain free acid or base. The anhydrous white crystalline salts are stable up to their melting points and undergo thermal decomposition leading to total volatilisation. The activation energy ( E a ∗), enthalpy change (Δ H) and entropy change (Δ S) were calculated for each step of the decomposition reaction of the salts by using some standard methods. In some cases phase transitions were also noticed. A linear correlation between E a ∗ and Δ S was noted for the decomposition reaction of the salts. The stability order of the salts with respect to E a ∗ followed the trend C 2H 5NH 3X < (C 2H 5) 3NHX < (C 2H 5) 2NH 2X. The probable mechanistic paths of the decomposition reactions are proposed.