Open AccessThe mechanism of thermal elimination of urea and thiourea derivatives. Part 2. Rate data for pyrolysis of N‐acetyl‐N′‐phenylthiourea and N‐benzoyl‐N′‐arylthioureas
Author(s) -
AlAwadi Nouria,
Elnagdi Mohamed Hilmy,
Mathew Tommy,
ElGamry Ibrahim
Publication year - 1997
Publication title -
heteroatom chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.283
H-Index - 42
eISSN - 1098-1071
pISSN - 1042-7163
DOI - 10.1002/(sici)1098-1071(1997)8:1<63::aid-hc10>3.0.co;2-2
Subject(s) - chemistry , thiourea , benzoyl chloride , medicinal chemistry , urea , pyrolysis , reaction rate constant , thermal decomposition , nuclear chemistry , organic chemistry , kinetics , physics , quantum mechanics
The first‐order rate constants of N‐acetyl‐N′‐phenylthiourea (1), N‐benzoyl‐N′‐phenyl‐(2a), N‐benzoyl‐N′‐(4‐nitrophenyl)‐(2b), N‐benzoyl‐N′‐(3‐chlorophenyl) (2c), N‐benzoyl‐N′‐(4‐chlorophenyl) (2d), and N‐benzoyl‐N′‐(4‐methylphenyl)thiourea (2e) were measured between 423 and 500 K. The reactions were homogeneous and unimolecular with log A (s −1 ) = 12.0, 13.2, 13.8, 10.9, 11.8, and 12.7 and E a kJ mol −1 = 130.3, 141.4, 134.6, 114.9, 124.1, and 141.1, respectively. The rate data gave good Hammett correlation with σ o values, and ρ is 1.99 at 450 K. © 1997 John Wiley & Sons, Inc.