The kinetics of 2-butanol and i-butanol pyrolysis were investigated by measuring multi-species time histories using shock tube/laser absorption methods. Species time histories of OH, H2O, C2H4, CO, and CH4 were measured behind reflected shock waves using UV and IR laser absorption during the high-temperature decomposition of 1% butanol/argon mixtures. Initial reflected shock temperatures and pressures for these experiments covered 1270-1640 K and 1.3-1.9 atm. These are the first multi-species time history measurements in shock tubes for 2-butanol and i-butanol. Production pathways and reaction rate sensitivities for the measured species are analyzed using the recent Sarathy et al. [36] detailed mechanism. It is observed that radical branching in 2-butanol is a highly complicated process with multiple reactions indistinguishably affecting the measured species profiles. However, i-butanol exhibits relatively simple radical branching, and evidence is presented that demonstrates radical branching must be adjusted to favor the iC(4)H(8)OH-beta channel. Recommendations for i-butanol + H reactions are suggested and significant improvements between measurements and simulations using the Sarathy et al. [36] mechanism are achieved with these revised values. (C) 2013 Published by Elsevier Inc. on behalf of The Combustion Institute.