aldehydes presentation.pptx

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First things first !!

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Page 1: aldehydes presentation.pptx

First things first !!

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Carbonyl Group

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

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Carbonyl Group

What is the chemical structure of CARBONYL??

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Carbonyl Group

[C=O]

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Carbonyl Group

Carbonyl compounds can be devided into two classes :

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Carbonyl Group

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

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Carbonyl Group

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Carbonyl Group

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

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Carbonyl Group

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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

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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.

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Welcome To !!!

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ALDEHYDES !!

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

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ALDEHYDES !!

What is the chemical formula for aldehydes?

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ALDEHYDES !!

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

ALDEHYDES !!

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

ALDEHYDES !!

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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.

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ALDEHYDES !!

NomenclatureSteps to remember!

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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.

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Notes in naming Aldehydes

Notice!

Nomenclature !!

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

Nomenclature !!

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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 !!

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But wait !!

There’s more !!

Some basic !!

Branched Substituent !!

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Isopropyl !!

Sec - butyl !!

Tert - butyl!!

Iso – butyl !!

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Isopropyl !!

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Sec - butyl !!

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Tert – butyl !!

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Iso - butyl !!

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Important thing in naming aldehydes

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

Nomenclature !!

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Nomenclature !!

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Nomenclature !!When choosing the parent of an aldehyde

Identify the longest chain

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Application !!Formaldehyde

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

polymeric materials

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

and Ketones

Positive test :Formation of a precipitate is a positive test

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Tests for Aldehydes !!

Tollen’s Test for Aldehydes

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

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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.

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Tests for Aldehydes !!

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Nomenclature !!

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Nomenclature !!

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Nomenclature !!