|
In chemical kinetics, the Lindemann mechanism, sometimes called the Lindemann-Hinshelwood mechanism, is a schematic reaction mechanism. Frederick Lindemann discovered the concept in 1922 and Cyril Hinshelwood developed it. It breaks down a stepwise reaction into two or more elementary steps, then it gives a rate constant for each elementary step. The rate law and rate equation for the entire reaction can be derived from this information. The Lindemann mechanism is used to model gas phase decomposition or isomerization reactions. Although the net formula for a decomposition or isomerization appears to be unimolecular and suggests first-order kinetics in the reactant, the Lindemann mechanism shows that the unimolecular reaction step is preceded by a bimolecular activation step so that the kinetics may actually be second-order in certain cases.〔() "Gas phase decomposition by the Lindemann mechanism" by S. L. Cole and J. W. Wilder. ''SIAM Journal on Applied Mathematics'', Vol. 51, No. 6 (Dec., 1991), pp. 1489-1497.〕 == Activated reaction intermediates == The overall equation for a unimolecular reaction may be written A → P, where A is the initial reactant molecule and P is one or more products (one for isomerization, more for decomposition). A Lindemann mechanism typically includes an activated reaction intermediate, labeled A *. The activated intermediate is produced from the reactant only after a sufficient activation energy is acquired by collision with a second molecule M, which may or may not be similar to A. It then either deactivates from A * back to A by another collision, or reacts in a unimolecular step to produce the product(s) P. The two-step mechanism is then : ::: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lindemann mechanism」の詳細全文を読む スポンサード リンク
|