Transcript 01. Structure and properties of organic compounds. Aldehydes fnd

LECTURE
CLASSIFICATION, STRUCTURE,
NOMENCLATURE AND
PROPERTIES OF ORGANIC
COMPOUNDS.
TYPES OF CHEMICAL REACTIONS
Lecturer: Iryna R. Bekus

Organic Chemistry – the chemistry of
the hydrocarbons and their derivatives;
the chemistry of carbon compounds.
Bioorganic Chemistry was study
structure and properties of compounds,
which are in human body.
Such as: proteins, lipids, hormones, carbohydrates,
vitamins, enzyme, fats, at el.

CLASSIFICATION

By structure of carbon chain:
Acyclic — compounds, that don’t contain any
cycle in their molecules.
Saturated — compounds that contain only bonds and nо  - bonds (simple – C – C –
bonds).
Alkanes — saturated hydrocarbons that contain
only – C – C – and – C – H –  bonds.
Unsaturated — compounds that contain bonds and  - bonds (double bonds (– C = C –)
or triple (– C  C – ) bonds, and simple – C –
C – bonds).
Alkenes — unsaturated hydrocarbons thаt
contain only one – C – C – double bond
(– C = C –).
Diene — unsaturated compounds thаt contain
two double – C – C – bonds.
Alkynes — unsaturated hydrocarbons thаt
contain – C – C – triple bond (– C  C – ).
Cyclic — organic compounds thаt contain any
cycle in its molecules.
Carbocyclic - hydrocarbons containing а cycle
that consists of only Carbon atoms.
Cycloalkanes — saturated hydrocarbons
containing а Carbon cycle.
Cycloalkenes — ansaturated hydrocarbons
containing а Carbon cycle.
Arenes — aromatic compounds thаt contain
benzoic ring.
Heterocyclic - organic compounds thаt contain
cycle between atoms of Carbon and other
elements (S, O, N).
Functional Group is any
part of an organic
compound, which is not а
carbon-hydrogen
or
carbon-carbon single bon.
By functional groups:
There are mono-, poly- and heterofunctional group
in the structure of organic compounds:
Monofunctional group – contains only 1 functional group.
C2H5—OH
Polyfunctional group
functional group.
–
H2C
CH
H2C
contains
several
similar
OH
OH
OH
Heterofunctional group – contains several different functional
O
group.
C
H
OH
NOMENCLATURE
Common (trivial)
 International (IUPAC –
International Union of Pure
and Applied Chemistry)
system of nomenclature was first
introduced in 1947.

General rules for IUPAC nomenclature:

1.
2.
3.

The IUPAC name of any organic compound
essentially consists of three parts:
word root;
suffix;
prefix.
Thus, а complete IUPAC name of an organic
compound consists of the following parts:
• Secondary prefix + Primary prefix + Word
root + Primary suffix + Secondary suffix
SUFFIX
There are two types of suffixes:
 Primary suffix. А primary suffix is always
added to the word root to indicate whether the
carbon chain is saturated оr unsaturated. The
three basic primary suffixes are given below:

Secondary suffix. А secondary suffix is then added
to the primary suffix to indicate the nature of the
functional group present in the organic compound.
Secondary suffixes of some important functional
groups are given below:
PREFIX
There are two types of prefixes:
Primary prefix. А primary prefix is
used simply to distinguish cyclic
from acyclic compounds.
For example, in case of carbocyclic
compounds, а primary prefix, cyclo
is used immediately before the
word root. Thus:
 Cyclopentane
Secondary prefix. In IUPAC system of nomenclature,
certain groups are not considered as functional
groups but instead are treated as substituents. These
are called secondary prefixes.
Complete structural formula:
H
H
H
H
H
H
H
H
C
H
C
C
C
C
H
H
H
C
C
C
C
C
H
H
butane
H
H
H
H
H
H
H
H
hexane
Shorten structural formula:
H2
C
H2C
CH2
H2C
CH2
C
H2
hexane
CH3—CH2—CH2—CH3
butane
Types of organic reactions.
All the organic reactions can be broadly
classified into the following four types:
(a) substitution reactions,
 (b) addition reactions,
 (c) elimination reactions,
 (d) rearrangement reactions.

(I) Substitution reactions which are brought about by
nucleophiles are called nucleophilic substitution
reactions:
CH3OH + CH3COOH  CH3COOCH3 + H2O
(II) Substitution reactions which are brought about by
electropholes are called electrophilic substitution
reactions:
(III) Substitution reactions brought about by free
radicals are called free radical substitution
reactions:
CH4 +Cl2 → CH3Cl +HCl
Addition reactions
Addition reactions are of the following three types:
Addition reactions brought about by nucleophiles are called
nucleophilic addition reactions:
Addition reactions brought about by electrophiles are called
electrophilic addition reactions.
Addition reactions brought about by free radicals are called
free radical addition reactions.

Elimination reactions. An elimination reaction is
one that involves the loss of two atoms orgroups of
atoms form the same or adjacent atoms of a
substance leading the formation of a multiple
(double or triple) bond:
These are of two types:
 -Elimination reactions.
 -Elimination reactions.
Reactions involving the migration of an atom or a group from
one atom to another within the same molecule are called
rearrangement reactions.
Oxidation — а net decrease in the number of  bonds
to hydrogen or electropositive element, or а net increase
in the number of bonds to electronegative elements. А
net loss of electrons.
Reduction — а net increase in the number of 
bonds to hydrogen or electropositive element, or а
net decrease in the number of bonds to
electronegative elements. А net gains electrons.
ALCOHOL

In chemistry, an alcohol is an organic compound in
which the hydroxyl functional group (-OH) is bound
to a carbon atom. In particular, this carbon center
should be saturated, having single bonds to three
other atoms.
Systematic names
In the IUPAC system, the name of the alkane
chain loses the terminal "e" and adds "ol", e.g.,
"methanol" and "ethanol“
Classification of alcohols

Alcohols with one hydroxyl group - monohydric alcohol

Alcohols with two hydroxyl groups - dihydric alcohol
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Alcohols with three hydroxyl groups - trihydric alcohols
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Alcohols with four or more hydroxyl groups - polyhydric
alcohols
The saturated monohydric alcohols have the general
formula CnH2n+1OH or ROH. Their functional group
is -OH.
They can be further classified into:
1) Primary Alcohol
Here the carbon atom bearing the hydroxyl group is
attached to just one other carbon atom.
2) Secondary Alcohol
Here the carbon atom bearing the hydroxyl group is
attached to two other carbon atoms.
3)Tertiary Alcohol
Here the carbon atom bearing the hydroxyl group is
attached to three other carbon atoms.
Carbonyl Group
Carbon atom joined to oxygen by a
double bond
 Ketones

Aldehydes
Aldehydes
Comes from alcohol dehydrogenation
 Obtained by removing of a hydrogen
from an alcohol

Aldehydes
Both common and IUPAC names
frequently used
 Common names from acids from
which aldehydes can be converted

Aldehydes
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
IUPAC
Longest chain with aldehyde
Drop “e” and add “-al”
• Acetaldehyde
Propionaldehyde
Phenylethanal
Ketones
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Naming:
• Drop “e”, add “-one”
• Many common names
• Simplest is 3 carbons
C. name: acetone
 IUPAC: propanone

Physical Properties of Aldehydes
and Ketones

Carbon-oxygen double bond is very polar
• Affects boiling points
• More than ethers (C-O bonds)
• Less than alcohols (C-OH bonds)
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Odors
• Low aldehydes very pungent
• High aldehydes pleasant odors (perfumes)

Solubility
• Similar to alcohols and ethers
• Soluble up to about 4 carbons
• Insoluble after that
Preparation of Aldehydes
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Oxidation
Hydration of alkynes (Kucherov reaction).
Reaction occurs by way of an enol
intermediate formed by Markovnikov
addition of water to the triple bond.
Oxosynthesis.
Interaction of alkenes with carbone
(II) oxide, at the higher temperature,
pressure and presence of catalyst.
Preparation of Ketones

Oxidation
Chemical Properties of Aldehydes
and Ketones
Both undergo combustion reactions
 Oxidation

• Aldehydes can be oxidized, ketones
can’t
• See
Tollen’s reagent
 Benedict’s reagent
 Fehling’s reagent

Reactions of aldehyde oxidation

With Tollens’ reagent – “silver
mirror” reaction.
With Fehling reagent: after heating red
precipitate of copper (I) oxide formed.
Chemical Properties of Aldehydes
and Ketones

Reduction
• Variety of agents can reduce aldehydes
and ketones to alcohols
Chemical Properties of Aldehydes
and Ketones
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Hydration
• Formaldehyde dissolves readily in water
• Acetaldehyde somewhat also

Form hydrates
Chemical Properties of Aldehydes
and Ketones
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Addition of Alcohols to Carbonyl
Groups
• Hemiacetal

Aldehyde + alcohol
• Hemiketal

Ketone + alcohol
Chemical Properties of Aldehydes
and Ketones
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Hemiacetals + HCl = acetal

Hemiketal + HCl = ketal
Thank you for attention