aldehydes presentation.pptx

First things first !!

Carbonyl Group

A carbonyl group is a chemically organic functional group composed of a carbon atom double-bonded to an oxygen atom

Carbonyl Group

What is the chemical structure of CARBONYL??

Carbonyl Group

[C=O]

Carbonyl Group

Carbonyl compounds can be devided into two classes :

Carbonyl Group

Class I - Has a group attached to the acyl group that can function as a leaving group.

Carbonyl Group

Carbonyl Group

Class II - Does not have a group attached to the acyl group that can function as a leaving group.

Carbonyl Group

Reactions at the Carbonyl Group

Reagents that attack the electron-poor d+ end of this bond are nucleophiles.

Nucleophiles  (from “nucleus loving”, or “positive-charge loving”). A nucleophile is a reactant that provides a pair of electrons to form a new covalent bond

Reactions at the Carbonyl Group

Reagents that attack the electron-rich d - end of the C=O bond are called electrophiles.

electrophilicity (from “electron-loving”, or “negative-charge loving”). An electrophile is a species that accepts a pair of electrons to form a new covalent bond.

Welcome To !!!

ALDEHYDES !!

When the carbonyl group is directly bonded to, at least, one hydrogen atom the compound is said to be an aldehyde,

ALDEHYDES !!

What is the chemical formula for aldehydes?

ALDEHYDES !!

When the carbonyl group is directly bonded to, at least, one hydrogen atom the compound is said to be an aldehyde,

ALDEHYDES !!

but when only directly connected to carbon atoms it is described as a ketone.

ALDEHYDES !!

ALDEHYDES !!Aldehyde is an organic compound which contain formyl group. This functional group, in its structure R-CHO, consist of carboxyl centre bonded to R group and hydrogen. The group with R is called as formyl group and aldehyde group.

ALDEHYDES !!

NomenclatureSteps to remember!

Nomenclature !!Identify and name the parent.

Identify and name the substituents.

Assign a locant to each substituent.

1.2

. 3.4

.Assemble the substituents alphabetically.

Notes in naming Aldehydes

Notice!

Nomenclature !!

In this line structure, the double bonded oxygen should always on the very end of the molecule

Nomenclature !!

And In this 2nd line structure, the double bonded oxygen is somewhere in the middle of carbon chain and hydrogen attached near to the oxygen.

Nomenclature !!

But wait !!

There’s more !!

Some basic !!

Branched Substituent !!

Isopropyl !!

Sec - butyl !!

Tert - butyl!!

Iso – butyl !!

Isopropyl !!

Sec - butyl !!

Tert – butyl !!

Iso - butyl !!

Important thing in naming aldehydes

When naming the parent, the suffix “-al” indicates the presence of an aldehyde group.

Nomenclature !!

Nomenclature !!

Nomenclature !!When choosing the parent of an aldehyde

Identify the longest chain

Application !!Formaldehyde

Use in:• Tanning• Preserving• Embalming• Germicide• Fungicide• Production on

polymeric materials

Tests for Aldehydes !!2,4-DNP Test for Aldehydes

and Ketones

Positive test :Formation of a precipitate is a positive test

Tests for Aldehydes !!

Tollen’s Test for Aldehydes

Positive Test:Formation of silver mirror or a black precipitate is a positive test.

Tests for Aldehydes !!Jones (Chromic Acid)

Oxidation Test for AldehydesPositive Test:

A positive test for aldehydes and primary or secondary alcohols consists in the production of an opaque suspension with a green to blue color. Tertiary alcohols give no visible reaction within 2 seconds, the solution remaining orange in color. Disregard any changes after 15 seconds.

Tests for Aldehydes !!

Nomenclature !!

Nomenclature !!

Nomenclature !!