The thermal behaviour of acetanilide (Ac) and two of its analogues, namely the para-ethoxyacetanilide (p-Eto Ac) and the para-bromoacetanilide (p-Br Ac), which are used as analgesics in the pharmaceutical industry was studied with a simultaneous TG/DSC unit. The examined analgesics showed two endothermic DSC peaks due to melting and vaporization. By combining the experimental TG data with the corresponding reference vapour pressure data obtained with the Antoine equation the plot of P versus v was derived. From the slope of this equation the constant k-value was determined for Ac. Then, using the same k-value the vapour pressures of p-Eto Ac and p-Br Ac were determined in the same temperature range. The vaporization enthalpies for all the studied compounds were obtained from different methods and a very good agreement was found. Vaporization follows a zero-order kinetics. The activation energy of vaporization (E-vap) was calculated from the dynamic TG experiments, using the Arrhenius equation. (C) 2004 Elsevier B.V. All rights reserved.
Thermal analysis study on vaporization of some analgesics. Acetanilide and derivatives / VECCHIO CIPRIOTI, Stefano; S., Catalani; Vanessa, Rossi; Tomassetti, Mauro. - In: THERMOCHIMICA ACTA. - ISSN 0040-6031. - 420:1-2 SPEC. ISS.(2004), pp. 99-104. (Intervento presentato al convegno 6th Mediterranean Conference on Calorimetry and Thermal Analysis tenutosi a Oporto, PORTUGAL nel JUL 27-29, 2003) [10.1016/j.tca.2003.09.039].
Thermal analysis study on vaporization of some analgesics. Acetanilide and derivatives
VECCHIO CIPRIOTI, Stefano;TOMASSETTI, Mauro
2004
Abstract
The thermal behaviour of acetanilide (Ac) and two of its analogues, namely the para-ethoxyacetanilide (p-Eto Ac) and the para-bromoacetanilide (p-Br Ac), which are used as analgesics in the pharmaceutical industry was studied with a simultaneous TG/DSC unit. The examined analgesics showed two endothermic DSC peaks due to melting and vaporization. By combining the experimental TG data with the corresponding reference vapour pressure data obtained with the Antoine equation the plot of P versus v was derived. From the slope of this equation the constant k-value was determined for Ac. Then, using the same k-value the vapour pressures of p-Eto Ac and p-Br Ac were determined in the same temperature range. The vaporization enthalpies for all the studied compounds were obtained from different methods and a very good agreement was found. Vaporization follows a zero-order kinetics. The activation energy of vaporization (E-vap) was calculated from the dynamic TG experiments, using the Arrhenius equation. (C) 2004 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
