Types of
Organic
Reactions
By Prof. Liwayway Memije-Cruz

Organic reactions are chemical reactions involving
organic compounds.
 organic reactions
are used in the
construction of new
organic molecules.
 The production of
many man-made
chemicals such as
drugs, plastics, food
additives, fabrics
depend on organic
reactions.

What are the different types of
organic reactions?
1. Substitution
reactions
2. Elimination
reactions
3. Addition reactions
4. Radical reactions
5. Oxidation-Reduction
reactions

Types of Organic Reactions

Electrophiles
 molecule or ion that accepts a pair of electrons to make a new covalent
bond (from the Greek for "electron loving").
 same thing as a Lewis acid.
 molecule, ion or atom that is electron deficient in some way can behave as
an electrophile.
 Electron deficiency would include a formal positive charge (methyl
carbocation), a partial positive charge (d+), usually in conjunction with a
polar bond (such as H-Cl) or an open octet (borane). "E" or "E+" are
common abbreviations for generic electrophiles.

Nucleophiles
 molecule or ion that donates a
pair of electrons to form a new
covalent bond (from the Greek for
"nucleus loving").
 same thing as a Lewis base.
 Any molecule, ion or atom that
has electrons that can be shared
can be a nucleophile. The most
common indications that
electrons are available to be
shared are formal negative
charge (iodide ion), a partial
negative charge (d-), usually in
conjunction with a polar bond
(methyl magnesium bromide), a p
bond (isobutylene) or lone pairs
(ammonia). "Nuc" or "Nu" are
common abbreviations for
generic nucleophiles.

Substitution Reaction
 reaction where one atom or a group of
atoms is substituted by another atom or
a group of atoms to form a new
substance.
 example of C – Cl bond, in which the
carbon atom usually has a partial
positive charge due to the presence of
highly electronegative chlorine atoms

Elimination Reactions
 involve the elimination and removal of the adjacent
atoms.
 One of the examples of elimination reaction is the
conversion of ethyl chloride to ethylene.
CH3CH2Cl → CH2=CH2+ HCl
 In the above reaction the eliminated molecule is HCl,
which is formed by the combination of H+ from the
carbon atom which is on the left side and Cl– from the
carbon atom which is on the right side.

Addition Reactions
 just the opposite of an elimination
reaction.
 In an addition reaction, the components
or molecules of A and B are added to the
carbon-carbon multiple bonds and this is
called an addition reaction.
 In the reaction given below when HCl is
added to ethylene, it will give us ethylene
chloride.
HCl + CH2 = CH2 →
CH3CH2Cl

Radical Reactions
 Most of the organic reactions involve radicals
and their movement.
 Addition of a halogen to a typically saturated
hydrocarbon involves free radical
mechanism.
 There are usually three stages involved in a
radical reaction which are, initiation,
propagation, and termination. Initially when
the weak bond is broken initiation of the
reaction takes place with the formation of
free radicals. After that when the halogen is
added to the hydrocarbon a radical is
produced and finally, it gives alkyl halide.

Oxidation–Reduction Reactions
 can often be identified by changes in the
number of oxygen atoms at a particular position
in the hydrocarbon skeleton or in the number of
bonds between carbon and oxygen at that
position
 increase in either corresponds to an oxidation,
whereas a decrease corresponds to a reduction.
 increase in the number of hydrogen atoms in a
hydrocarbon is often an indication of a
reduction.

The Oxidation State of Carbon in Oxygen- and
Nitrogen-Containing Functional Groups.
(a) In a hydrocarbon, oxidation is indicated by an increase in the
number of oxygen atoms or carbon–oxygen bonds or a decrease in
the number of hydrogen atoms. (b) In nitrogen-containing
compounds, the number of carbon–nitrogen bonds changes with the
oxidation state of carbon.

The Oxidation State of Carbon in Oxygen- and Nitrogen-
Containing Functional Groups.
b) In compounds with a carbon–nitrogen bond, the
number of bonds between the C and N atoms increases
as the oxidation state of the carbon increases.

Summary
 The common classes of organic reactions—substitution,
elimination, addition, oxidation-reduction, and radical—all
involve reacting electrophiles with nucleophiles.
 There are common patterns to how organic reactions occur.
 In a substitution reaction, one atom or a group of atoms in a substance is
replaced by another atom or a group of atoms from another substance.
Bulky groups that prevent attack cause the reaction to be sterically
hindered.
 In an elimination reaction, adjacent atoms are removed with subsequent
formation of a multiple bond and a small molecule. An addition reaction is
the reverse of an elimination reaction.
 Radical reactions are not very selective and occur in three stages: initiation,
propagation, and termination.
 Oxidation–reduction reactions in organic chemistry are identified by the
change in the number of oxygens in the hydrocarbon skeleton or the number
of bonds between carbon and oxygen or carbon and nitrogen.

References:
 https://www.toppr.com/guides/chemistry/organic-c
 https://byjus.com/chemistry/types-of-organic-react
 https://www.wikihow.com/Learn-About-the-Types-o
 https://chem.libretexts.org/Textbook_Maps/
General_Chemistry/Map%3A_