Carboxylic
Acid COOH
Definition
Organic compounds that contain
monovalent functional group – COOH are called Ketones.
General
Formula
They are denoted by R may be any
alkyl group. The general formula for ketone is
CnH2n+1 – COOH
Where n may be any natural number.
Structure
The Structural formula of Carboxylic
Acid shows that it contains a carbonyl group.
ROH-C=O
Examples
Acetic Acid (CH3COOH)
Preparation
Carboxylic Acid can be prepared by
the following methods.
1. From Grignard’s Reagent
In presence of dry ether and halogen
acid when Grignard’s reagent with carbondioxide then Carboxylic Acid is formed.
R-Mg-X + O=C=O —-> COOR-Mg-X
—-> RCOOH + MgX2
CH3-Mg-X + 0=C=0 —-> COOCH3-Mg-X
—-> CH3COOH + MgX2
2. From Oxidation of Alcohol
In presence of oxidizing agent such
as a mixture of K2Cr2O7 and concentrated K2SO4, when primary alcohol is
oxidized then aldehyde is form, which on further oxidation convert into
Carboxylic Acid.
RCH2-OH —-> RCHO —-> RCOH-O
CH3CH2-OH —-> CH3CHO —->
CH3COH=O
3. From Dehydrogenation of Alcohol
In presence of catalyst Co – Mo
couple, when primary alcohol is heated at elevated temperature then aldehyde is
formed, which in presence of a mixture of oxidizing agent such as K2Cr2O7 and
concentrated H2SO4 convert into Carboxylic Acid.
RCH2-OH —-> RCHO —-> RCOH-O
CH3CH2-OH —-> CH3CHO —->
CH3COH=O
4. From Ethyne
This method is used for the
preparation of acetaldehyde. In presence of catalyst H2SO4 and HgSO4 when
ethyne reacts with water than unstable, intermediate vinyle alcohol is formed
which on rearrangement of atoms convert into acetaldehyde.
H-C≡C-H + H-OH —-> C2H3OH —-> CH3-CHO —-> CH3-COOH
Uses of Carboxylic Acid
1. Carboxylic Acids are used as laboratory
reagents.
2. Acetic acid is used as solvent for
phosphorus, sulphur, gums and resins.
3. It is widely used in artificial
leather production.
4. Acetic acid is used to prepare
acetates, esters and cellulose acetate silk.
5. After colouring, it is used as
vinegar.
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