Thermal decomposition of methyl butanoate (MB) diluted in argon was studied behind the reflected shock waves in the temperature range of 1229-1427 K using single pulse shock tube (SPST). The post shock mixtures were analyzed quantitatively using gas chromatography (GC) and qualitatively using Fourier-transform infrared (FTIR) spectroscopy. Methane (CH 4 ), ethylene (C 2 H 4 ), and acetylene (C 2 H 2 ) were the major decomposition products. The minor products are ethane (C 2 H 6 ), propylene (C 3 H 6 ), 1,3-butadiene (C 4 H 6 ) and methyl acrylate (C 4 H 6 O 2 ). The obtained first order rate coefficient for the decomposition of MB is k total (1229-1427 K) = (3.08 ± 1.11) × 10 12 exp (-(53.6 kcal mol -1 ± 4.7)/RT) s -1 , and for the formation of C 2 H 4 channel, the rate coefficient obtained to be k ethylene (1229-1427 K) = (7.92 ± 2.72) × 10 9 exp (-(47.6 kcal mol -1 ± 4.5)/RT) s -1 . Theoretical kinetic calculations were also performed for the unimolecular hydrogen transfer reactions using canonical variational transition state theory (CVT) with small-curvature tunneling (SCT) corrections. The temperature dependent rate coefficients for the overall reaction were computed in the temperature range of 500-2500 K, and were used to derive the Arrhenius expression: ݇ ௧௧ ௧௬ (500-2500 K) = (9.05 ± 1.91) × 10 13 exp (-(70.7 kcal mol -1 ± 2.0)/RT) s -1 . A reaction scheme containing 39 species and 66 elementary 2 reactions was proposed to simulate the reactant and product concentrations over the temperature range of 1229-1427 K. The agreement between the experimental results and the model prediction for all the species is observed to be good. The decomposition of MB happens mostly via intramolecular hydrogen transfer than C-C bond and C-O bond fission. Majority of these intramolecular hydrogen transfer reactions are lower energy barrier reactions than the homolytic bond fission reactions.

A single pulse shock tube was used to study the thermal decomposition of 2-pentanol in the temperatures between 1110 and 1325 K. Three major decomposition products are methane, ethylene, and propylene. The minor products detected in lower concentration are ethane, acetylene, acetaldehyde, 1-pentene, and 2-pentene. The rate coefficient for the overall decomposition of 2-pentanol was found to be k(1110-1325 K) = (4.01 ± 0.51) × 10 exp(-(36.2 ± 4.7)/RT) s, where the activation energies are given in kcal mol. To simulate reactant and product distribution over the experimentally studied temperatures between 1110 and 1325 K, a reaction scheme was constructed with 34 species and 39 reactions. In addition to this, the temperature and pressure dependent rate coefficients were computed for various unimolecular dissociation pathways using RRKM theory. The high pressure limit rate coefficient for overall decomposition of 2-pentanol was obtained to be k(500-2500 K) = (9.67 ± 1.11) × 10 exp(-(67.7 ± 2.9)/RT) s. The calculated high pressure rate coefficients and experimentally measured rate constants are in good agreement with each other. The reaction is primarily governed by the unimolecular elimination of water.

Thermal decomposition of tetramethylsilane (TMS) diluted in argon was studied behind the reflected shock waves in a single pulse shock tube (SPST) in the temperature range of 1058-1194 K. The major products formed in the decomposition are methane (CH 4 ) and ethylene (C 2 H 4 ); whereas ethane and propylene were detected in lower concentrations. The decomposition of TMS seems to be initiated via Si-C bond scission by forming methyl radicals (CH 3 ) and trimethylsilyl radicals ((CH 3 ) 3 Si). The total rate coefficients obtained for the decomposition of TMS were fit to Arrhenius equation in two different temperature regions 1058-1130 K and 1130-1194 K. The temperature dependent rate coefficients obtained are k total (1058-1130 K) = (4.61 ± 0.70) ×10 18 exp (−(79.9 kcal mol −1 ± 3.5)/RT) s −1 , k total (1130-1194 K) = (1.33 ± 0.19) ×10 6 exp (−(15.3 kcal mol −1 ± 3.5)/RT) s −1 . The rate coefficient for the formation of CH 4 is obtained to be k methane (1058-1194 K) = (4.36 ± 1.23) ×10 14 exp (−(61.9 kcal mol −1 ± 4.9)/RT) s −1 . A kinetic scheme containing 21 species and 38 elementary reactions was proposed and simulations were carried out to explain the formation of all the products in the decomposition of tetramethylsilane.

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