National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
J Phys Chem A. 2012 Oct 11;116(40):9825-31. doi: 10.1021/jp305120h. Epub 2012 Sep 26.
Dilute concentrations of normal-butanol has been decomposed in single pulse shock tube studies in the presence of large quantities of a chemical inhibitor that suppresses contributions from chain decomposition. Reaction temperatures and pressures are in the range of [1126-1231] K and [1.3-6.5] bar. Ethylene and 1-butene are the only products. The mechanism of the initial decomposition steps involves direct elimination of water and C-C bond cleavage. The fundamental high pressure unimolecular decomposition rate expressions are k(C(4)H(9)OH → CH(3) + CH(2)CH(2)CH(2)OH) = 10(16.4±0.4) exp(42410 ± 800 [K]/T) s(-1); k(C(4)H(9)OH → CH(3)CH(2) + CH(2)CH(2)OH) = 10(16.4±0.4) exp(-41150 ± 800 [K]/T) s(-1); k(C(4)H(9)OH → CH(3)CH(2)CH(2) + CH(2)OH) = 10(16.4±0.4) exp(-41150 ± 800 [K]/T) s(-1); and k(C(4)H(9)OH → CH(3)CH(2)CH═CH(2) + H(2)O) = 10(14.0±0.4) exp(-35089 ± 800 [K]/T) s(-1), where the rate expressions for C-C bond cleavage are based on assumptions regarding the relative rates of the three processes derived from earlier studies on the effect of an OH group on rate expressions. All reactions are in the high pressure limit and suggest that the step size down in the presence of argon is at least 1300 cm(-1). These rate expressions are consistent with the following H-C bond dissociation energies: BDE(H-CH(2)CH(2)CH(2)OH) = 417.2 ± 7 kJ/mol, BDE(H-CH(2)CH(2)OH) = 419.2 ± 7 kJ/mol, and BDE(H-CH(2)OH) = 401.7 ± 9 kJ/mol, with an estimated uncertainty of 6 kJ/mol. The kinetics and thermodynamic results are compared with estimates used in the building of combustion kinetics databases.
在存在大量化学抑制剂的情况下，通过单脉冲激波管研究了正常丁醇的稀释浓度，该抑制剂抑制了链分解的贡献。反应温度和压力范围为 [1126-1231] K 和 [1.3-6.5] bar。乙烯和 1-丁烯是唯一的产物。初始分解步骤的机制涉及水的直接消除和 C-C 键的断裂。基本的高压单分子分解速率表达式为 k(C(4)H(9)OH → CH(3) + CH(2)CH(2)CH(2)OH) = 10(16.4±0.4) exp(42410 ± 800 [K]/T) s(-1); k(C(4)H(9)OH → CH(3)CH(2) + CH(2)CH(2)OH) = 10(16.4±0.4) exp(-41150 ± 800 [K]/T) s(-1); k(C(4)H(9)OH → CH(3)CH(2)CH(2) + CH(2)OH) = 10(16.4±0.4) exp(-41150 ± 800 [K]/T) s(-1); 和 k(C(4)H(9)OH → CH(3)CH(2)CH═CH(2) + H(2)O) = 10(14.0±0.4) exp(-35089 ± 800 [K]/T) s(-1)，其中 C-C 键断裂的速率表达式基于对早期研究中 OH 基团对速率表达式影响的三个过程相对速率的假设。所有反应均处于高压极限，表明在氩气存在下的步长至少为 1300 cm(-1)。这些速率表达式与以下 H-C 键离解能一致：BDE(H-CH(2)CH(2)CH(2)OH) = 417.2 ± 7 kJ/mol，BDE(H-CH(2)CH(2)OH) = 419.2 ± 7 kJ/mol，和 BDE(H-CH(2)OH) = 401.7 ± 9 kJ/mol，估计不确定度为 6 kJ/mol。动力学和热力学结果与燃烧动力学数据库构建中使用的估计值进行了比较。
