Comprehensive Thermochemical Study of Cyclic Five- and Six-Membered N,N '-Thioureas

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Silva, ALR (Author) FCUP; Maria D M C R Ribeiro da Silva (Author) FCUP

Journal

Title: Journal of Chemical & Engineering Data

Vol. 62

Pages: 2584-2591

ISSN: 0021-9568

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 5 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-00M-N7V

DOI: 10.1021/acs.jced.7b00083

Abstract (EN): An experimental and computational study of the thermochemical and structural properties of ethylenethiourea (ETU) has been carried out. The enthalpies of combustion and sublimation, measured respectively by rotating-bomb combustion calorimetry and Calvet microcalorimetry, yielded the gas-phase enthalpy of formation of ETU at T = 298.15 K. This latter parameter was also derived from high-level molecular orbital calculations at the G3(MP2)//B3LYP level of theory, leading to a value in excellent agreement with the one obtained from experimental data. With the purpose of evaluating the influence of the ring size in the enthalpy of formation of cyclic N,N'-thiourea derivatives, the calculation of the enthalpy of formation of N,N'-trimethylenethiourea (MTU) was performed using the G3-(MP2)//B3LYP approach. The effects of substituents (carbonyl and thiocarbonyl) on the molecular stability of several N-alkyl (cyclic) ureas/thioureas were also studied.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8