Writing Equations for Organic Reactions
Writing Equations for Organic Reactions
(1) Like
other reactions, equations for organic reactions are usually drawn with a
single reaction arrow (→) between the starting material and product, but other
conventions make these equations look different from those encountered in
general chemistry.
(2) The
reagent, the chemical substance with which an organic compound reacts, is
sometimes drawn on the left side of the equation with the other reactants.
At other times,
the reagent is drawn above the reaction arrow itself, to focus attention on the
organic starting material by itself on the left side.
(3) The
solvent and temperature of a reaction may be added above or below the arrow.
(4) The
symbols (hʋ) and (Δ) are used for reactions that require light or heat,
respectively.
The Following
figure presents an organic reaction in different ways.
(5) When
two sequential reactions are carried out without drawing any intermediate
compound, the steps are usually numbered above or below the reaction arrow.
This convention signifies that the first step occurs before the second, and the
reagents are added in sequence, not at the same time.
In this
equation only the organic product is drawn on the right side of the arrow.
Although the reagent CH3MgBr contains both Mg and Br, these elements
do not appear in the organic product, and they are often omitted on the product
side of the equation. These elements have not disappeared. They are part of an
inorganic by-product (HOMgBr in this case), and are often of little interest to
an organic chemist.
Notes
(1) Often
the solvent and temperature of a reaction are omitted from chemical equations,
to further focus attention on the main substances involved in the reaction.
(2)
Most organic reactions take place in a liquid solvent. Solvents solubilize key reaction
components and serve as heat reservoirs to maintain a given temperature.
Reference: Organic chemistry / Janice Gorzynski Smith , University of Hawai’i at Manoa / (Third edition) , 2011 . USA
Reference: Organic chemistry / Janice Gorzynski Smith , University of Hawai’i at Manoa / (Third edition) , 2011 . USA
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