ORGANIC
CHEMISTRY
Project book
BANEEN NATASYA FAIRUL
CARBONYL COMPOUNDS
Part A
Introduction
WHAT ARE CARBONYL COMPOUNDS?
A carbonyl compound can be defined as a chemically
organic functional group which is composed of a
carbon atom double bonded to an oxygen atom.
Carbonyl compounds are comprised of aldehydes
(carbonyl group bonded to at least one hydrogen
atoms) and ketones (carbonyl group bonded to two
carbon atoms).
WHAT IS THE FUNCTIONAL GROUP OF CARBONYL
COMPOUNDS?
The functional group of a carbonyl compound consists of a carbon atom double
bonded to a oxygen atom, C=O.
STRUCTURE OF CARBONYL COMPOUNDS
CaRBONYL COMPOUNDS:
Aldehydes vs Ketones
R-CHO
More reactive than ketones
- undergo oxidation to
form carboxylic acid
R-CO-R'
Are not able to oxidise
without breaking the
carbon chain
Carbon atom bounded to
at least 1 hydrogen
atom
Carbon atom bounded to
2 other carbon atoms
Carbonyl compounds at
the end of the chain
Carbonyl compounds in
the middle of the
chain
Usually found in
volatile compounds
Usually found in
sugars
DRAW THE STRUCTURE OF ANY 3 ALDEHYDE AND KETONE
AND NAME THEM RESPECTIVELY.
PREPARATION
Chemical
reaction
OXIDATION OF ALCOHOL
OZONOLYSIS OF ALKENE
FREIDAL-CRAFTS ACYLATION
CHEMICAL
PROPERTIES
OXIDATION
REDUCTION
NUCLEOPHILIC ADDITION
REACTIONS
H A L O F O R M
R E A C T I O N
PREPARATION OF CARBONYL COMPOUNDS
OXIDATION OF ALCOHOL
→
→
→
PRIMARY ALCOHOL
CARBOXYLIC ACID
SECONDARY ALCOHOL
KETONE
TERTIARY ALCOHOL
NO REACTION
POTASSIUM
DICHROMATE
CHROMIUM
TIOXIDE
Primary alcohols are oxidized to form either aldehydes or carboxylic acids
PRIMARY
ALCOHOL
(which requires further oxidation of the aldehyde). To form aldehyde, the
alcohol must be heated under a reflux with oxidizing agent. The reaction
requires excess alcohol so that it does not oxidize again to form
carboxylic acid. Once the aldehyde is formed, it is distilled.
Secondary alcohols are oxidized to form ketones. For example, heating
SECONDARY
ALCOHOL
up propan-2-ol (secondary alcohol) with potassium dichromate (VI)
solution acidified with dilute sulphuric acid will form propanone. Different
reaction conditions do not affect the product. Secondary alcohols will
not form carboxylic acids.
Tertiary alcohols cannot be oxidized by potassium dichromate (VI)
TERTIARY
ALCOHOL
solution and thus, no reaction occurs. This is because tertiary alcohols do
not have any Hydrogen attached to carbon. In the oxidation reaction
involving primary and secondary alcohols, the oxidizing agent removes
the hydrogen from the -OH group. Because tertiary alcohols do not have
said hydrogen, the reaction cannot occur.
OZONOLYSIS
OF ALKENE
Ozonolysis is the process of
oxidatively cleaving alkenes using
ozone (O3 ). This process allows the
C=C double bond to be replaced
by double bonds with oxygen, C=O.
Ozone in gas form passes through
an alkene solution in methanol or
dichloromethane.
The
product
(ozonide molecule) is then reduced
to form a carbonyl compound.
Then, the C=C bonds are replaced
with C=O bonds.
FRIEDEL-CRAFTS ACYLATION
STEP 1
STEP 2
PRODUCT
The first step creates a carbocation
that acts as an electrophile in the
reaction.
This
activates
the
haloalkane. Secondary and tertiary
halides only form free carbocation in
this step.
In step 2, an electrophilic attack
occurs on benzene, which results in
many resonance forms. The halogen
then reacts with the intermediate and
picks up a hydrogen in order to
eliminate the positive charge.
The products
Acylation is:
of
the
Friedel-crafts
PHYSICAL
PROPERTIES
BOILING POINT
The boiling point of methanal is -19 celcius. The boiling point for ethanal is 21
celcius. In general, the boiling point of aldehydes and ketones increases with
the increase of molecular weight. Thus, boiling point depends on the
strength of intermolecular forces.
Vander Waals dispersion forces
When the chain gets longer and there is an
increase in number of electrons, the
attraction increases. For both aldehydes
and ketones, boiling point increases with
the number of carbon atoms.
SOLUBILITY
Aldehydes and ketones are soluble in water,
however their solubility decreases with the
increase in length of chain. For example,
methanal, ethanal and propanone (all of
which are small in size) are miscible with
water in almost all proportions.
Vander Waals dipole-dipole attraction
Aldehydes and ketones are polar due to
the presence of C=O double bonds.
Attraction exists between the permanent
dipoles and the molecules surrounding it.
Because of this, they have higher boiling
point than similar-sized hydrocarbons.
Chemical Properties
OXIDATION
OXIDATION OF ALDEHYDE
OXIDATION OF KETONE
The product of oxidation of aldehyde depends
on whether the reaction is done under acidic
or alkaline conditions. When the reaction
occurs under acidic conditions, the aldehyde
is oxidized to form carboxylic acid. Under
alkaline conditions, salt is formed because it
reacts with the alkali. The presence of
Hydrogen allows aldehydes to be easily
oxidized.
Ketones do not have a hydrogen atom similar
to aldehydes. Thus, they are resistant to
oxidation. Only strong oxidizing agents such as
potassium manganate (VII) solution are able to
oxidize ketones. Ketones are oxidized through
the breaking of carbon-carbon bonds.
Many reagents can cause the oxidation of
aldehydes to carboxylic acids. The reagent
that is most commonly used is CrO3 in
aqueous acid, also known as the Jones
Reagent. This reaction generally occurs at
room temperature.
Oxidation of cyclopentanone to form pentanedioic acid
Baeyer-Villiger Oxidation
STEP 1
Conversion of hexanal to hexanoic acid using ones Reagent
Mechanism:
STEP 2
STEP 3
STEP 4
STEP 5
Among common sources of hydride nucleophiles (molecules or substances which
have a tendency to donate electrons) include lithium aluminum hydride (LiAlH4) and
sodium borohydride (NaBH4). The hydride anions are not present during the reaction,
as the reagents serve as a source of hydride because of the presence of a polar
metal-hydrogen bond. Since aluminum is less electronegative as compared to boron,
the Al-H bond in lithium aluminum hydride is more polar, thus making it a stronger
reducing agent.
The addition of hydride anion to a carbonyl compound produces alkoxide anion,
which on protonation, yields the corresponding alcohols. Reaction involving
aldehydes form primary alcohols and ketones form secondary alcohols.
Metal hydride reductions will result in alkoxide salts which are insoluble and requires
further hydrolysis to form the alcohol product. The alcohol product is then isolated. In
sodium borohydride reduction, the methanol solvent system will hydrolyze automatically.
For the lithium aluminum hydride reduction water is usually added into the second step.
The lithium, sodium, boron and aluminum will end up as soluble inorganic salts at the
end of the reaction.
NUCLEOPILIC ATTACK BY THE HYDRIDE ANION
THE ALKOXIDE IS PROTONATED
Nucleophilic
Addition Reaction
In organic chemistry, a nucleophilic
addition reaction can be defined as an
addition reaction in which a chemical
compound with an electrophilic double (or
triple) bond reacts with a nucleophile, thus
breaking said bond.
The nucleophilic addition reaction between
Hydrogen cyanide (HCN) and carbonyl
compounds will form cyanohydrins. The rate
of reaction can be increased using base
catalysts. Cyanide anion (CN-) acts as a
powerful nucleophile which will attack the
carbonyl carbon to form a sigma bond.
Carbonyl compounds are polar because of
the C=O bond. Because of this, the
carbonyl carbon becomes electrophilic in
nature. The cyanide anion (nucleophile)
attacks the carbonyl carbon, forming an
intermediate, which must be protonated to
produce cyanohydrin.
Aldehydes are more reactive towards
nucleophilic addition reaction when
compared to ketones because the
secondary carbocations formed by ketones
are stabilized by the adjacent R groups.
The primary carbocations in aldehydes are
less stable as compared to ketones, thus
making it more susceptible to nucleophilic
attacks.
The haloform reaction is the reaction of
methyl
ketone
with
chlorine(Cl),
bromine(Br), or iodine(I) in the presence
of hydroxide ions. This reaction will form
a carboxylate ion and haloform. Only
one aldehyde undergoes the haloform
reaction, which is acetaldehyde.
Reaction
MECHANISM
When iodine is used, the haloform
reaction can be used to identify methyl
ketones. Iodoform is a yellow solid with
a characteristic odor, and this
confirmation test is known as the
iodoform test. Alcohols with the general
structural formula 1 give positive
iodoform test because under specific
conditions, they will be oxidized to form
their corresponding methyl ketone.
USES
BENZALDEHYDE
confer almond flavor to foods and scented
products
bee repellant
precursor to other organic compounds
(pharmaceuticals, plastic additives, etc.)
FORMALDEHYDE
manufacture of resin (example: urea)
manufacture of dye
plywood adhesive
tissue fixation and preservation
sterilization or disinfection
CINNAMALDEHYDE
as a flavourant (in chewing gum, ice cream,
candy, and beverages)
as an agrichemical against mosquito larvae
In glucose and galactose, the carbonyl group is on the C1
carbon, forming an aldehyde group. In fructose, the
carbonyl group is on the C2 carbon, forming a ketone
group. The former sugars are called aldoses based on
the aldehyde group that is formed; the latter is
designated as a ketose based on the ketone group.
Carboxylic acid
𝓘𝓝𝓣𝓡𝓞𝓓𝓤𝓒𝓣𝓘𝓞𝓝
WHAT ARE
CARBOXYLIC
ACID?
WHAT IS THE
FUNCTIONAL
GROUP FOR
CARBOXYLIC
ACID?
STRUCTURE
OF
CARBOXYLIC
ACID
Carboxylic acids are a group of organic compounds
where the carbon atom is bonded to the oxygen by
double bond and bonded to a hydroxyl group with a
single bond. A fourth bond links the carbon atom to
a hydrogen or another univalent combining group.
The carboxyl group (COOH) received its name from
the carbonyl group (C=O) and hydroxyl group (-OH).
In general, carboxylic acids
are represented by the
formula RCOOH, where R is
a hydrocarbon group.
Structure
DRAW STRUCTURE OF ANY 3
CARBOXYLIC ACID AND
NAME THEM RESPECTIVELY
DRAW THE STRUCTURE OF
ANY 3 DERIVATIVES OF
CARBOXYLIC ACID AND
NAME THEM RESPECTIVELY
n
o
i
t
c
a
Re
Preparation
1
OXIDATION OF PRIMARY
ALCOHOL AND ALDEHYDE
2
OXIDATION OF ALKYL BENZENE
3
HYDROLYSIS OF NITRILES
Chemical properties
1
ESTERS
2
AMIDE
3
ACYLCHLORIDE
Preparation of Carboxylic acid
Oxidation of Primary Alcohol and Aldehyde
When aldehydes are oxidized,
In the first step, one mol of water is added to the
they form carboxylic acids that
reactants in the presence of an acidic catalyst to
contain the same number of
produce a hydrate.
carbon atoms as the oxidizing
agents (potassium dichromate,
chromium trioxide, potassium
permanganate,
etc.).
In
equations, the oxygen from the
in the second step, the product (hydrate) will be
oxidizing agent is denoted by
oxidized to form carboxylic acid. Water is then
[O].
eliminated.
This reaction consists of two
steps.
Alkyl groups which contain benzylic hydrogens
on a carbon α to benzene ring will undergo
oxidation to acids with the aid of strong
oxidizing agents.
By
treating
alkylbenzene
with
potassium
permanganate(KMnO4), which will allow oxidation
to form benzoic acid.
Since
t-butylbenzene
does not contain a
benzylic hydrogen, it
does not oxidize and
thus the reaction does
not occur .
OXIDATION OF
ALKYL BENZENE
ACIDIC
The nitrile is heated under reflux with
dilute hydrochloric acid. This will
form carboxylic acid.
Example:
The reaction involving ethanenitrile
and hydrochloric acid will form
ethanoic acid and ammonium
chloride.
The reason why free acid is formed
rather than ammonium salt is
because ethanoate ions in the
ammonium will react with hydrogen
ions from HCL to produce ethanoic
acid.
ALKALINE
The nitrile is heated under reflux with
sodium hydroxide solution. This will
form sodium salt, as well as
ammonia gas.
Example:
The reaction involving ethanenitrile
and sodium hydroxide solution will
form
sodium
ethanoate
and
ammonia.
To form carboxylic acid, the final
solution must be acidified with a
strong acid such as dilute HCL or
dilute H2SO4. The ethanoate ion in
the sodium ethanoate will react with
hydrogen ions to form ethanoic acid.
PHYSICAL PROPERTIES
SOLUBILITY
POLARITY
Due to the very polar -COOH,
carboxylic acids will exhibit strong
intermolecular interactions.
Carboxylic acids are soluble in
organic solvents and water (due to
the hydrogen bonding). As mass
increases, the solubility of the
compound decreases.
BOILING POINT
The boiling point of carboxylic acids
are very high. They increase with the
increase of size due to the increase
in Van der Waals forces.
The boiling point is higher for
straight
chain
isomers.
More
branches will result in lower
intermolecular forces. Thus, the
boiling point decreases.
𝓟
𝓟 𝓱𝓱 𝔂𝔂 𝓼𝓼 𝓲𝓲 𝓬𝓬 𝓪𝓪 𝓵𝓵 𝓹𝓹 𝓻𝓻 𝓸𝓸 𝓹𝓹 𝓮𝓮 𝓻𝓻 𝓽𝓽 𝓲𝓲 𝓮𝓮 𝓼𝓼
FORMATION OF
ESTER
Esters are formed when carboxylic acids are heated with alcohols in the
presence of an acid catalyst (usually concentrated sulphuric acid). The use of
hydrogen chloride gas typically involves aromatic esters in which the carboxylic
acid contains a benzene ring, The esterification reaction is slow and reversible.
For example, to form ethyl ethanoate, the reactants are ethanoic acid and
ethanol.
Example:
FORMATION OF AMIDE
Ammonium ethanoate is formed from the
reaction involving ammonium carbonate
and excess ethanoic acid.
By adding ammonia to a carboxylic
acid, amides are formed. The reaction
is very slow and conducted at room
temperature. In this reaction, water
molecules are split out and a bond is
formed between the nitrogen atom
and carbonyl carbon atom.
The mixture is then heated to produce
ethanamide.
The reason excess ethanoic acid is used is
to prevent the dissociation of ammonium
salt before it is heated and dehydrates,
The excess of ethanoic acid is there to
prevent dissociation of the ammonium salt
before it dehydrates. The dissociation
ammonium salt will prevent the reaction
from completing.
The dissociation is also reversible.
First, the carboxylic acid is converted
into ammonium salt. After being
heated,
amides
will
form.
The
ammonium salt is produced by
adding ammonium carbonate to
excess acid.
Formation of
acylchloride
When carboxylic acid reacts with thionyl chloride, acid chloride will
form. During the reaction, the hydroxyl group of the carboxylic acid
is converted into a chlorosulfite intermediate. The chloride anion
formed in the reaction will act as a nucleophile.
Nucleophilic
attack on
Thionyl Chloride
Removal of Cl
leaving group
Nucleophilic
attack on the
carbonyl
Leaving group
removal
Deprotonation
USES
As a flavouring
ETHANOIC
ACID
As a preservative
Used with other chemicals to make
drugs, dyes, paints, insecticides,
and plastics
As an antibacterial agent
FORMIC
ACID
As a preservative
Used in coagulation of rubber
Used as a pesticide
Textile dye
FATTY
ACID
BENZOIC
ACID
Used in making soap
Preservative in food
PART C
AMINES
I NTRODUCTI ON
WHAT ARE AMINES?
In organic chemistry, amines can be defined as compounds and functional
groups which consists of basic nitrogen atoms with a lone pair.
Amines are formal derivatives of ammonia, where one or more hydrogen
atoms have been replaced with a substitute such as alkyl or aryl groups.
Inorganic derivatives of ammonia are also called amines. For example,
monochloramine (NCIH2).
WHAT IS THE FUNCTIONAL GROUP OF
AMINE
The functional group of an
amine consists of a nitrogen
atom with a lone pair of
electrons and also with one,
two, or three alkyl or aryl groups
attached.
STRUCTURE OF AMINES
𝓐𝓶𝓲𝓷𝓮
Reactions
1.
Preparation
AMINE ALKYLATION
2.. F O R M A T I O N O F A M I N E
FROM NITRILES
Chemical properties
1.
AMIDE FORMATION
2.
ELECTROPHILIC
SUBSTITUTION REACTION
3.
REACTION OF
AMINE WITH ACID
Amines
can
be
formed
from
halogenoalkanes.
Firstly,
the
halogenoalkane
is
heated
with
concentrated ammonia in ethanol. The
reaction is done in a sealed tube and
not under reflux.
Using halogenoalkanes such as 1bromoethane, amines and their salts
can be formed.
FORMATION OF
AMINE FROM
HALOGENOALKANES
To form primary amines, the reaction
requires two steps. The first step
involves the production of a salt. The
salt will be ethylammonium bromide
if 1-bromoethane is used.
There is also a possibility of
reversible reaction between salt and
excess ammonia.
The ammonia then removes a
hydrogen
ion
from
the
ethylammonium ion to form a
primary amine. in this case, it is
ethylamine. More ammonia should be
used so that the forward reaction is
more favored.
Secondary amine can also be formed. The
ethylamine
also
reacts
with
bromoethane. The two stages repeat. For
this reaction, the salt formed is
diethylammonium bromide.
Once again, there is a possibility of a
reversible reaction between the salt and
excess ammonia.
The ammonia removes a hydrogen ion
from the diethylammonium ion to form a
secondary amine, dethylamine,
To form tertiary amine, the diethylamine
reacts with bromoethane in the same
way. In the first stage, triethylammonium
bromide (salt) is formed. In the second
step, triethylamine is formed.
.
REDUCTION OF NITRILES
USING LITHIUM ALUMINIUM
HYDRIDE.
The nitrile reacts with the lithium
tetrahydriodoaluminate in ethoxyethane,
a diethyl ether. The next step involves
treatment of the product with dilute
acid.
To summarize, the carbon-nitrogen triple
bond will be reduced to form a primary
amine. Ethanenitrile will be reduced to
form ethylamine.
REDUCTION OF NITRILES USING HYDROGEN AND A METAL CATALYST
The carbon-nitrogen triple bond in a nitrile can be reduced through the reaction with hydrogen gas as
well as the presence of metal catalysts. Commonly used metal catalysts include palladium, platinum,
and nickel.
The conditions of this reaction are raised temperature and pressure. The temperature and pressure
depends on the catalyst used.
As an example, ethanenitrile can be reduced to ethylamine through the reaction with hydrogen in the
presence of a palladium catalyst.
Physical properties
Amines have a higher boiling point than
hydrocarbon however they have lower boiling
point than alcohol.
Amines are soluble in water due to the Hbonding interactions with water molecules.
Water solubility decreases as chain length
decreases and the degree of N-substitution
increases.
Amines tend to be gases when it has low
molecular weight, Heavier ones are typically
liquid at room temperature.
Amines exhibit strong odour. For example, a
fishy smell.
amide formation
Ethanoyl chloride reacts violently in a reaction with cold concentrated
ethylamine solution. A white product is formed. This product is the
mixture of N-ethylethanamide, which is an N-substituted amide, and
ethylammonium chloride.
Mechanism
or
Electrophilic
substitution
reaction
Electrophilic
substitution reactions
are chemical reactions
where an electrophile
displaces a functional
group (which is usually
but not limited to
hydrogen atom) in a
compound.
In this example, aniline
(aromatic amine) is
used.
Reaction of aniline with bromine water at room temperature
will produce 2,4,6-tribromoaline (a white precipitate. The
substitution will occur at the ortho and para position. Once
this substitution is carried out, the hydrolysis of substituted
amides to substituted amines occurs.
The lone pair of electrons present on nitrogen of acetanilide
interacts with the oxygen atom due to resonance. This causes
the lone pair of electrons on nitrogen to be less available for
transfer to the benzene ring. Therefore, the activating effect
of
–NHCOCH3 group is less as compared to amino group.
Reaction of
amine with acid
for this reaction, we will use the
Bronsted-Lowry theory (the base
will accept hydrogen ions). The
reaction of amine with acid is
similar
with
the
reaction
of
ammonia (a weak acid) with acid.
Ammonia reacts with acids to
produce ammonium ions. The
ammonia molecule picks up a
hydrogen ion from the acid and
attaches it to the lone pair on the
nitrogen.
notes:
Since
amines
carboxylic
are
acids
basic,
to
they
form
neutralize
ammonium
carboxylate salts. Upon heating to 200°C,
the
primary
dehydrate
amides.
and
to
secondary
form
the
amine
salts
corresponding
USES
Morphine and Demerol - analgesics
Pest control
Azo-dyes and nylon
Crop protection
Water purification
Tanning of leather
Methamphetamines and
amphetamines - recreational drugs