161001-84-9Relevant articles and documents
Kinetics and mechanisms of the gas-phase elimination of arylethyl N,N-dimethylcarbamates and ω-phenylalkyl N,N-dimethylcarbamates
Chuchani, Gabriel,Dominguez, Rosa M.,Rotinov, Alexandra,Herize, Armando
, p. 40 - 46 (2007/10/03)
The gas-phase elimination kinetics of several arylethyl N,N-dimethylcarbamates and ω-phenylalkyl N,N-dimethylcarbamates were determined in the temperature range 299.6-399.9 °C and pressure range 18-95 Torr. The reactions in a static system, seasoned with allyl bromide, and in the presence of a free radical suppressor are homogeneous and unimolecular and follow a first-order rate law. The rate coefficients are given by the Arrhenius equations: for 4-phenethyl N,N-dimethylcarbamate, log [k1 (s-1)] = (11.32 ± 0.22) - (166.9 ± 2.5) kJ mol-1 (2.303RT)-1; for methylphenethyl N,N-dimethylcarbamate, log[k1 (s-1)] = (12.07 ± 0.36) - (178.6 ± 4.3) kJ mol-1 (2.303RT)-1; for 4-methoxyphenethyl N,N-dimethylcarbamate, log[k1 (s-1)] = (11.03 ± 0.60) - (167.3 ± 7.1) kJ mol-1 (2.303RT)-1; for 4-nitrophenethyl N,N-dimethylcarbamate, log[k1 (s-1)] = (11.31 ± 0.54) - (163.7 ± 6.1) kJ mol-1 (2.303 RT)-1; for 3-(4-methoxyphenyl) propyl N,N-dimethylcarbamate, log [k1 (s-1)] = (13.52 ± 0.54) - (208.4 ± 6.8) kJ mol-1 (2.303 RT)-1; for 4-phenyl-1-butyl N,N-dimethylcarbamate, log [k1 (s-1)] = (12.00 ± 0.34) - (185.2 ± 4.2) kJ mol-1 (2.303 RT)-1; and for 5-phenyl-1-pentyl N,N-dimethyl carbamate, log [k1 (s-1)] = (11.79 ± 0.31) - (182.2 ± 3.9) kJ mol-1 (2.303RT)-1. The results imply the absence of anchimeric assistance of the phenyl group, while the acidity of the benzylic β-hydrogen appears to be responsible for a small but significant rate augmentation in these eliminations. Copyright
