Introduction to mechanisms
The mechanism for a reaction is the detailed set of bond–making and bond–breaking steps leading from reactants to products.There is often more than one plausible pathway for a reaction.
The overall reaction:
CH3Br + OH–
CH3OH + Br–
could occur in a single step
CH3Br + OH– CH3OH + :Br–
(C-Br bond breaks and the C-O bond forms simultaneously)
or in two steps
step 1: CH3Br+CH3 + Br –
(C–Br bond breaks)
step 2: H3C+ + OH– CH3–OH
(C–O bond forms)
Species like CH3+ which are formed in one step of a process and consumed in a subsequent step are known as intermediates.
CH3Br + OH–
CH3OH + Br–could occur in a single step
CH3Br + OH–
CH3OH + :Br–(C-Br bond breaks and the C-O bond forms simultaneously)
or in two steps
step 1: CH3Br
+CH3 + Br – (C–Br bond breaks)
step 2: H3C+ + OH–
CH3–OH(C–O bond forms)
Species like CH3+ which are formed in one step of a process and consumed in a subsequent step are known as intermediates.
Intermediates, like catalysts, do not appear in the overall equation for the reaction. Catalysts are different to intermediates in that they are a reactant in one step and a product in a subsequent step.