Pressure dependence of the reaction of 1-butanethiol with hydrogen atoms

• Published in: International journal of chemical kinetics Vol. 30; no. 12; pp. 923 - 932
• Main Authors: Kamo, Tohru, Yamada, Muneyoshi
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 1998
• ISSN: 0538-8066; 1097-4601
• DOI: 10.1002/(SICI)1097-4601(1998)30:12<923::AID-KIN7>3.0.CO;2-1

The reaction of 1‐butanethiol with hydrogen atoms was investigated at room temperature under pressures of 133, 266, 532, 2660, and 5320 Pa, using two types of fast‐flow discharge reactors; the main products were n‐butane and 1‐butene with total yields of more than 90%. In the reaction of 1‐butanethiol and deuterium atoms, monodeuterated 1‐butanethiol was observed by a photo‐ionizing mass spectrometer. The relative rate of the two initial reactions of 1‐butanethiol with hydrogen atoms was 0.272 (k1/k2). The n‐butane and 1‐butene are considered to be produced via chemically activated 1‐butanethiol on the basis of the pressure dependence of the two main products.
\scriptfont4=\seveni \scriptscriptfont4=\fivei
\halign{\hfill $#$&$#$\hfill &$#$\hfill &\hfill\qquad\qquad #\cr\rm 1\hbox{‐}C_{4}H_{9}S&\rm H&\rm +H\longrightarrow 1\hbox{‐}C_{4}H_{9}\cdot +H_{2}S& (1)\cr \rm 1\hbox{‐}C_{4}H_{9}S&\rm H&\rm +H\longrightarrow 1\hbox{‐}C_{4}H_{9}S\cdot +H_{2}& (2)\cr\rm 1\hbox{‐}C_{4}H_{9}S&\rm \cdot &\rm +H\longrightarrow 1\hbox{‐}C_{4}H_{9}SH\ast & (3)\cr } \bigskip\rm{}
Relative rates of molecular elimination of hydrogen sulfide and CS bond fission for the chemically activated 1‐butanethiol, k5/k4 and k6/k4, were 0.114 and 0.0552 under 532 Pa of pressure at room temperature. Activation energies of the two reactions were calculated to be 228 [kJ/mol] and 297 [kJ/mol], respectively, by use of RRKM on the base of estimated A factors.
\scriptfont4=\seveni \scriptscriptfont4=\fivei
\halign{\hfill $#$&$#$\hfill &$#$\hfill &\hfill\qquad\qquad #\cr\rm 1\hbox{‐}C_{4}H_{9}SH\ast +M&\rm \longrightarrow &\rm 1\hbox{‐}C_{4}H_{9}SH& (4)\cr \rm 1\hbox{‐}C_{4}H_{9}SH\ast &\rm \longrightarrow &\rm 1\hbox{‐}C_{4}H_{8}+H_{2}S& (5)\cr\rm 1\hbox{‐}C_{4}H_{9}SH\ast &\rm \longrightarrow &\rm 1\hbox{‐}C_{4}H_{9}\cdot +HS\cdot & (6)\cr } \bigskip\rm{}
© 1998 John Wiley & Sons, Inc. Int. J. Chem Kinet 30: 923–932, 1998