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Thermochemical and kinetic analysis on the addition reactions of H, O, OH, and HO 2 with 1,3 cyclopentadiene
Author(s) -
Zhong Xian,
Bozzelli Joseph W.
Publication year - 1997
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1997)29:12<893::aid-kin2>3.0.co;2-h
Subject(s) - chemistry , cyclopentadiene , kinetic energy , computational chemistry , medicinal chemistry , organic chemistry , catalysis , physics , quantum mechanics
Chemical activation and unimolecular dissociation pathway and kinetic analysis is presented on addition of radicals H, O, OH, and HO 2 to one of the two types of unsaturated carbons on cyclopentadiene. Addition of H atom or OH radical at the 1 position forms an allylic radical, which can break the weaker (allylic) carbon(SINGLEBOND)carbon bond, opening the 5‐carbon ring and forming a resonance stabilized radical. Addition at the 2 position is less exothermic and forms a secondary radical, which can break a carbon(SINGLEBOND)carbon bond to form a vinylic radical. The vinylic radical, if formed will rapidly react with O2 or decompose, β Scission. Addition at the 2 position usually results in reverse reaction (dissociation back to the reactants) O (3P) addition to the two types of unsaturated carbons on cyclopentadiene will form two diradical isomers which will quickly decompose to H atom plus cyclopentenone‐yl radicals, both of these cyclopentenone‐yl radicals will undergo β Scission to form stable cyclopentadienone and H atom. HO 2 addition to the unsaturated carbons on cyclopentadiene can form the cyclopentenyl (allylic) radical plus O 2 as products through intramolecular isomerization (H Shift) and then dissociation. Thermochemical property data for intermediate species along with rate constants for these radical addition reactions to cyclopentadiene and the decomposition/isomerization reactions of the adducts are estimated. Rate constants for each channel are calculated using bimolecular quantum Rice Ramsperger Kassel, QRRK, for k (E) with a modified strong collision analysis for fall off. Rate constants are presented over a range of pressure and temperature. Modeling results are compared to the limited literature data available for validation, i.e., to species profiles for appropriate reaction systems, where cyclopentadiene is a key intermediate. Rate constants on abstraction of the resonance stabilized H from the cyclopentadiene ring are also estimated. Major (vida infra) reaction channels and kinetic parameters Addition at the 1 position \scriptfont4=\seveni \scriptscriptfont4=\fivei\halign{\quad$\rm #$\hfil&\qquad $\rm #$\hfil\crCY13PD+H\Longleftrightarrow C=\!=CC.C=\!=C&\it k\rm =1.4\ 10^{14}\ \it T\rm ^{‐0.18}\ exp(‐3150/\it RT\rm )\crCY13PD+O\Longleftrightarrow \hbox{Cypent‐3‐eneone‐2yl}+H&\it k\rm =8.91\ 10^{12}\ \it T\rm ^{‐0.15}\ exp(‐590/\it RT\rm )\crCY13PD+OH\Longleftrightarrow C=\!=CC.C=\!=COH&\it k\rm =8.18\ 10^{12}\ \it T\rm ^{‐0.07}\ exp(‐850/\it RT\rm )\crCY13PD+HO_{2}\Longleftrightarrow \hbox{Cypentene‐3yl}+O2&\it k\rm =1.33\ 10^{15}\ \it T\rm ^{‐1.07}\ exp(‐9530/\it RT\rm )\cr} Addition at the 2 position \scriptfont4=\seveni \scriptscriptfont4=\fivei\halign{\quad$\rm #$\hfil&\qquad $\rm #$\hfil\crCY13PD+H\Longleftrightarrow C=\!=CC.+C\equiv\!\equiv C&\it k\rm =1.64\ 10^{36}\ \it T\rm ^{‐5.99}\ exp(‐32500/\it RT\rm )\crCY13PD+O\Longleftrightarrow \hbox{Cypent‐3‐eneone‐4yl}+H&\it k\rm =5.60\ 10^{12}\ \it T\rm ^{‐0.06}\ exp(‐200/\it RT\rm )\crCY13PD+OH\Longleftrightarrow C=\!=CC.OH+C=\!=C&\it k\rm =1.07\ 10^{33}\ \it T\rm ^{‐5.49}\ exp(‐37420/\it RT\rm )\cr} Units cm ‐3 mole ‐1 sec ‐1 , Ea in kcal/mole, temperature range 900‐1400 K © 1997 John Wiley & Sons, Inc. Int J Chem Kinet: 29: 893–913, 1997.