Thermal analysis of thione compounds

Abstract

The thermal behavior of thiourea (Tu), N, N, N', was investigated by means of conventional thermal analysis in Oz and N2 and IR spectroscopy of the residues on heating in air at various temperatures.At ordinary pressure, the compounds are thermally stable up to the melting points. After melting, they show high vapor pressure, combustion in 02 atmosphere and isomerization to ammonium thioeyanate, with the exception of Me4Tu.

Enthalpies and entropies of fusion and of sublimation at the temperature 298.15 K of thiourea and sevenN-alkylthioureas

“…7.179 ± 0.015 (27) (23) 15 (23) , 13.8 (18) 452.2 (19) 12.55 (19) 445.52 (20) 14.42 (20) (18) Donnelly et al, (19) and Kim et al (20) for thiourea. However, results from references 21 to 23 as a whole cannot be considered fully comparable with ours for the following reasons: commercial products were employed as received without any purification; no information is given about calibration procedures for both t.g.…”

“…and d.s.c., and i.r. studies by De Marco et al (21)(22)(23) on the thermal stability (28) 3.24 ± 0.06 3.27 ± 0.01 (28) (ICTAC)…”

“…and i.r. studies by De Marco et al (21)(22)(23) dealing with thiourea and a number of N -alkylthioureas.…”