Open AccessThe thermal decomposition of C{sub 2}H{sub 5}I
Author(s) -
S. S. Kumaran,
Meng-Chih Su,
K. P. Lim,
J.V. Michael
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/244547
Subject(s) - fission , chemistry , thermal decomposition , reaction rate constant , dissociation (chemistry) , branching fraction , atmospheric temperature range , analytical chemistry (journal) , yield (engineering) , kinetics , atomic physics , thermodynamics , physics , nuclear physics , organic chemistry , quantum mechanics , chromatography , neutron
The high temperature thermal dissociation of C{sub 2}H{sub 5}I has been characterized in this study. Kinetics and overall yield experiments were performed over the temperature range, 946--2,046 K, using the atomic resonance absorption spectrometric technique (ARAS) for the temporal detection of both product H- and I-atoms behind reflected shock waves. The C{sub 2}H{sub 5}I decomposition proceeds by both C-I fission and HI elimination. Rate constants for the C-I fission process, measured over the temperature and density ranges, 946--1,303 K and 0.82--4.4 {times} 10{sup 18} cm{sup {minus}3}, respectively, can be well represented to within {+-}37% by the first-order expression: k = 6.34 {times} 10{sup 9} exp({minus}15,894 K/T) s{sup {minus}1}. Overall yield data for atomic product gave a branching ratio for C-I fission of (0.87 {+-} 0.11) suggesting that 13% of the reaction proceeds through molecular HI elimination. This conclusion is consistent with earlier studies that showed C-I fission to be the dominant dissociation channel. The temperature and pressure dependences of the dissociation rate constants and the yield data have been theoretically described using three formulations of unimolecular rate theory. The best description was obtained with a full Master`s equation analysis. However, all three calculations confirm that the HI elimination pathway is lower lying than the C-I fission process by {approximately} 3 kcal/mole