Functional groups

Functional Groups
By Prof. Liwayway Memije-Cruz

Organic Chemistry
 The study of the structure, properties, composition, reactions,
and preparation of carbon-containing compounds, which
include not only hydrocarbons but also compounds with any
number of other elements, including hydrogen (most
compounds contain at least one carbon–hydrogen bond),
nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur.
 This branch of chemistry was originally limited to compounds
produced by living organisms but has been broadened to
include human-made substances such as plastics. The range of
application of organic compounds is enormous and also
includes, but is not limited to, pharmaceuticals, petrochemicals,
food, explosives, paints, and cosmetics.

Organic Chemistry
• study of the structure,
properties, composition,
reactions, and preparation of
carbon-containing
compounds, which include
not only hydrocarbons but
also compounds with any
number of other elements,
including hydrogen (most
compounds contain at least
one carbon–hydrogen bond),
nitrogen, oxygen, halogens,
phosphorus, silicon, and
sulfur.

• originally limited to compounds
produced by living organisms but
has been broadened to include
human-made substances such as
plastics.
• range of application of organic
compounds is enormous and also
includes, but is not limited to,
pharmaceuticals, petrochemicals,
food, explosives, paints, and
cosmetics.

Functional Groups
• specific group of atoms within molecules that are
responsible for the characteristic chemical reactions
of those molecules.
• attached to the carbon backbone of organic molecules.
• determine the characteristics and chemical reactivity
of molecules.
• collections of atoms in organic chemistry molecules
that contribute to the chemical characteristics of the
molecule and participate in predictable reactions.

• collections of atoms in organic chemistry
molecules that contribute to the chemical
characteristics of the molecule and
participate in predictable reactions.
• contain oxygen or nitrogen or sometimes
sulfur attached to a hydrocarbon skeleton.
• R in each structure is a wildcard notation for
the rest of the molecule's atoms.

Most Common Organic Functional
Groups

Alcohol (Hydroxyl Functional Group)
• any organic compound in which a hydroxyl
group (-OH) is bound to a carbon atom of an
alkyl or substituted alkyl group. The general
formula for a simple acyclic alcohol is
CnH2n+OH.
• is an oxygen atom bonded to a hydrogen atom.
• Hydroxyls are often written as OH on structures
and chemical formulas.

Ball-and-stick model of an alcohol
molecule (R3COH)
• The red and grey
balls represent the
hydroxyl group (-
OH). The three
"R's" stand for
carbon
substituents or
hydrogen atoms

• Due to the presence of an -OH group, alcohols can
hydrogen bond leading to higher boiling points
compared to their parent alkanes.
• Alcohols are polar in nature. which is attributed to the
difference in electronegativity between the carbon and
the oxygen atoms.
• In chemical reactions, alcohols often cannot leave the
molecule on their own; to leave, they often become
protonated to water, which is a better leaving group.
Alcohols also can become deprotonated in the presence of
a strong base.

What is protonated and deprotonated?
• Deprotonation is the removal (transfer)
of a proton (a hydrogen cation, H+) from
a Brønsted–Lowry acid in an acid-base
reaction. The species formed is the
conjugate base of that acid.
• Protonation is the addition (transfer) of
proton to a Brønsted–Lowry base, is
protonation.

Brønsted-Lowry Theory of Acids
and Bases.
• also called proton theory of acids and bases.
• introduced independently in 1923 by the Danish
chemist Johannes Nicolaus Brønsted and the English
chemist Thomas Martin Lowry
• states that any compound that can transfer a proton to
any other compound is an acid, and the compound that
accepts the proton is a base.
• proton is a nuclear particle with a unit positive
electrical charge; it is represented by the symbol H+
because it constitutes the nucleus of a hydrogen atom.

Nomenclature of Alcohols
• According to the IUPAC nomenclature system, an
alcohol is named by dropping the terminal “-e” of the
parent carbon chain (alkane, alkene, or alkyne in most
cases) and the addition of “-ol” as the ending.
• If the location of the hydroxyl group must be specified, a
number is inserted between the parent alkane name and
the “-ol” (propan-1-ol) or before the IUPAC name (1-
propanol). If a higher priority group is present, such as
an aldehyde, ketone or carboxylic acid, then it is
necessary to use the prefix “hydroxy-” instead of the
ending “-ol.”

Uses of Alcohols
• found in beverages,
antifreeze, antiseptics, and
fuels.
• can be used as preservatives
for specimens in science
• can be used in industry as
reagents and solvents
because they display an
ability to dissolve both polar
and non-polar substances.

Ether Functional Group
• consists of an
oxygen atom
forming a bridge
between two
different parts of a
molecule.
• Ethers have
formula ROR.

Nomenclature of Ethers
• In IUPAC method, the form is: [short alkyl
chain][oxy][long alkyl chain]. For example, the
IUPAC name for ethyl methyl ether would be
methoxyethane.
• In cyclic ethers, the stem of the compound is known
as a oxacycloalkane. The “oxa” is an indicator of the
replacement of the carbon by an oxygen in the ring.
An example is oxacyclopentane, a five-membered
ring in which there are four carbon atoms and one
oxygen atom.

Tetrahydrofuran (THF)
• The common name
of the cyclic ether
“oxacyclopentane”
is tetrahydrofuran,
or THF.
• a common organic
solvent that is
miscible with water.

Properties of Ethers
• nonpolar due to the presence of an alkyl group
on either side of the central oxygen.
• have lower boiling points compared to alcohols
of similar molecular weight.
• Ethers are more polar than alkenes, but not as
polar as esters, alcohols or amides of
comparable structures.
• have relatively low chemical reactivity, but they
are still more reactive than alkanes

Aldehyde Functional Group
• made up of carbon
and oxygen
double-bonded
together and
hydrogen bonded
to the carbon.
• Aldehydes have
formula R-CHO.

Ketone Functional Group
• a carbon atom double
bonded to an oxygen
atom that appears as a
bridge between two
other parts of a
molecule.
• Another name for this
group is the carbonyl
functional group.

Carboxylic Acid Functional
Group
• Also known as the
carboxyl functional group.
• The carboxyl group is an
ester where one
substituent R is a
hydrogen atom.
• The carboxyl group is
usually denoted by -
COOH

Properties and Uses of Carboxyl
group
• used as precursors to form other compounds
such as esters, aldehydes, and ketones.
• can exhibit hydrogen bonding with themselves,
especially in nonpolar solvents leading to
increased stabilization of the compounds and
elevates their boiling points.
• used in the production of polymers,
pharmaceuticals, solvents, and food additives

Ester Functional Group
• The ester group is
another bridge group
consisting of a
carbonyl group
connected to an ether
group.
• Esters have formula
RCO2R.

Nomenclature of esters
• The word “ester” was coined in 1848 by German
chemist Leopold Gmelin, probably as a contraction of
the German Essigäther, meaning acetic ether.
• Ester names are derived from the parent alcohol and
acid. For example, the ester formed by ethanol and
ethanoic acid is known as ethyl ethanoate; “ethanol” is
reduced to “ethyl,” while “ethanoic acid” is reduced to
“ethanoate.”
• Other examples of ester names include methyl
propanoate, from methanol and propanoic acid, and
butyl octanoate, from butane and octanoic acid.

Physical Properties of Esters
• more polar than ethers, but less so
than alcohols.
• more volatile than carboxylic acids
of similar molecular weight.
• soluble in water.

Amine Functional Group
• derivatives of
ammonia (NH3)
where one or
more of the
hydrogen atoms
are replaced by an
alkyl or aryl
functional group.

Applications of Amines
• Amines are ubiquitous in biology. Many
important molecules are amine-based, such
as neurotransmitters and amino acids.
• starting material for dyes and models for
drug design.
• used for gas treatment, such as removing
CO2 from combustion gases.

Amide Functional Group
• combination of a carbonyl group and an
amine functional group.

Thiol Functional Group
• similar to the hydroxyl group except the oxygen atom
in the hydroxyl group is a sulfur atom in the thiol
group.
• Thiol functional group is also known as a sulfhydryl
functional group.
• Thiol functional groups have formula -SH.

Phenyl Functional Group
• This group is a common ring
group. It is a benzene ring where
one hydrogen atom is replaced by
the R substituent group.
• Phenyl groups are often denoted
by the abbreviation Ph in
structures and formulas.
• Phenyl groups have formula
C6H5.

Reference
• https://courses.lumenlearning.com/boundless-
chemistry/chapter/functional-group-names-properties-and-
reactions/
• https://www.thoughtco.com/most-common-organic-
functional-groups-608700
• https://www.britannica.com/science/Bronsted-Lowry-theory
• https://www.compoundchem.com/2014/02/17/organic-
chemistry-reaction-map/
• https://www.masterorganicchemistry.com/wp-
content/uploads/2012/08/Functional_groups.pdf

Functional groups

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