Rate coefficients for the reactions of OH with butanols from 298 K to temperatures relevant for low-temperature combustion

Rate coefficients for the reactions of OH with n, s, and iso-butanol have been measured over the temperature range 298 to similar to 650 K. The rate coefficients display significant curvature over this temperature range and bridge the gap between previous low-temperature measurements with a negative temperature dependence and higher temperature shock tube measurements that have a positive temperature dependence. In combination with literature data, the following parameterizations are recommended: k(1,OH + n-butanol)(T) = (3.8 +/- 10.4) x 10(-19)T(2.48 +/- 0.37)exp ((840 +/- 161)/T) cm(3) molecule(-1) s(-1) k(2,OH + s-butanol)(T) = (3.5 +/- 3.0) x 10(-20)T(2.76 +/- 0.12)exp ((1085 +/- 55)/T) cm(3) molecule(-1) s(-1) k(3,OH + i-butanol)(T) = (5.1 +/- 5.3) x 10(-20)T(2.72 +/- 0.14)exp ((1059 +/- 66)/T) cm(3) molecule(-1) s(-1) k(4,OH + t-butanol)(T) = (8.8 +/- 10.4) x 10(-22)T(3.24 +/- 0.15)exp ((711 +/- 83)/T) cm(3) molecule(-1) s(-1) Comparison of the current data with the higher shock tube measurements suggests that at temperatures of similar to 1000 K, the OH yields, primarily from decomposition of beta-hydroxyperoxy radicals, are similar to 0.3 (n-butanol), similar to 0.3 (s-butanol) and similar to 0.2 (iso-butanol) with beta-hydroxyperoxy decompositions generating OH, and a butene as the main products. The data suggest that decomposition of beta-hydroxyperoxy radicals predominantly occurs via OH elimination.