Carboxylic acids: Acidic strength and factors affecting it

A. Reactions due to hydrogen atom of carboxyl group

1. Acidic character

a. Action with blue litmus
all carboxylic acids turn blue litmus red.


b. Reaction with metals: liberation of hydrogen
Carboxylic acids react with active metals such as Na, K, Ca, Mg, Zn, etc., to form their salts with the liberation of hydrogen.

c. Action with alkalies: formation of salts
Carboxylic acids neutralize alkalies forming salts and water.

d. Action with carbonates and bicarbonates: evolving carbon dioxide
Carboxylic acids decompose carbonates and bicarbonates evolving carbon dioxide with brisk effervescence.


Mechanism of acidic character


In the COOH group due to resonance in the OH, O acquires some positive charge the electron pair of OH is drawn towards O. This displacement of electrons causes the release of a proton and a carboxylate ion, RCOO- is formed. This is the reason for acidic character of carboxylic acids.

The strength of acids can be expressed in terms of dissociation constant Ka or Ph number of PKa number which is pKa = -log Ka

A stronger acid will have a higher Ka value but smaller PKa value.

Effects of substituents on acidic strength of acids

Electron releasing substituents: Alkyl is an electron releasing group. If the H atom of formic acid (HCOOH) is replaced by CH3 group to form acetic acid (CH3COOH) the alkyl group will tend to increase the electron density on the oxygen atom of the O-H bond. This increase will make removal H+ ion difficult in comparison to formic acid.

Acetic acid is a weaker acid in comparison to formic acid.

The electron release effect is called +I effect. As +I effect increases, acidic strength will go down. As more alkyl groups are there +I effect increases
CH3
Therefore acidic property is stronger or more for CH3COOH.

Acidic strength is in the following order
acidic strength of HCOOH>CH3COOH>CH3CH2COOH>(CH3)2CHCOOH

Electron withdrawing substituents: Substituents like halogens tend to withdraw the electron charge. Halogens are electron attracting atoms(-I inductive effect). They withdraw the electrons from the carbon to which they are attached and this effect is transmitted throught the chain. The increases positive charge on O atom in the O-H bond and dissociation of H+ ion or proton takes place more easily.

Hence chloroacetic acid is stronger acid than acetic acid.

IIT JEE Revision - Ch.28 Carboxylic Acid - Core Points

JEE syllabus

Carboxylic acids:
Preparation, properties
Characteristic reactions
formation of esters,
acid chlorides and amides,
ester hydrolysis;


---------
1. Carboxylic acids are the compound containing carboxyl group in their molecules.

-C with a double bond with oxygen and single bond with OH

2. These acids can be aliphatic or aromatic.

aliphatic acids:

Formic acid HCOOH
Acetic acid CH-3COOH
Isobutyric acid (Branched)

aromatic acids

Bezoic acid : H in benzene substituted by COOH

m-Nitrobenzoic acid: One more H substituted by NO-2

o-Toluic acid (o refers to ortho) Benzoic acid with one more H substituted by CH-3

3. Methods of Preparation of Monocarboxylic Acids:
1. From oxidation of primary alcohols
2. By oxidation of aldehydes and ketones.


A. Reactions due to hydrogen atom of carboxyl group

1. Acidic character

a. Action with blue litmus
all carboxylic acids turn blue litmus red.


b. Reaction with metals: liberation of hydrogen
Carboxylic acids react with active metals such as Na, K, Ca, Mg, Zn, etc., to form their salts with the liberation of hydrogen.

c. Action with alkalies: formation of salts
Carboxylic acids neutralize alkalies forming salts and water.

d. Action with carbonates and bicarbonates: evolving carbon dioxide
Carboxylic acids decompose carbonates and bicarbonates evolving carbon dioxide with brisk effervescence.


Mechanism of acidic character


In the COOH group due to resonance in the OH, O acquires some positive charge the electron pair of OH is drawn towards O. This displacement of electrons causes the release of a proton and a carboxylate ion, RCOO- is formed. This is the reason for acidic character of carboxylic acids.

The strength of acids can be expressed in terms of dissociation constant Ka or Ph number of PKa number which is pKa = -log Ka

A stronger acid will have a higher Ka value but smaller PKa value.

Effects of substituents on acidic strength of acids

Electron releasing substituents: Alkyl is an electron releasing group. If the H atom of formic acid (HCOOH) is replaced by CH3 group to form acetic acid (CH3COOH) the alkyl group will tend to increase the electron density on the oxygen atom of the O-H bond. This increase will make removal H+ ion difficult in comparison to formic acid.

Acetic acid is a weaker acid in comparison to formic acid.

The electron release effect is called +I effect. As +I effect increases, acidic strength will go down. As more alkyl groups are there +I effect increases
CH3
Therefore acidic property is stronger or more for CH3COOH.

Acidic strength is in the following order
acidic strength of HCOOH>CH3COOH>CH3CH2COOH>(CH3)2CHCOOH

Electron withdrawing substituents: Substituents like halogens tend to withdraw the electron charge. Halogens are electron attracting atoms(-I inductive effect). They withdraw the electrons from the carbon to which they are attached and this effect is transmitted throught the chain. The increases positive charge on O atom in the O-H bond and dissociation of H+ ion or proton takes place more easily.

Hence chloroacetic acid is stronger acid than acetic acid.



Some more topics need to be covered


Carboxylic acid - practice questions
http://makoxmcqs.com/chemistry-mcqs-for-jee-main-carboxylic-acids-and-their-derivatives-mcq-practice-sheet/


Updated on 18 January 2020
5 February  2008

JEE - Study Guide - 14. Organic Compounds with functional Groups Containing Oxygen – II (Aldehydes, Ketones, Carboxylic Acids and their Derivatives)

Sections in the chapter

Part A: Aldehydes and Ketons

14A.1 Nomenclature of aldehydes and ketones
14.2 Isomerism in aldehydes and ketones
14.3 General methods of preparation of aldehydes and ketones
14.4 Physical properties of aldehydes and ketones
14.5 Chemical properties of aldehydes and ketones
P.P. 14A.13 to 14A.20
14.6 Commercially important carbonyl compounds
14.7 Distinction between properties of aldehydes and ketones
14.8 Distinction between some pairs (Chemical tests)

Conceptual Questions 12

Additional Numerical Problems for Practice:
Revision Exercises
Very Short Answer questions : 31
Short Answer Questions : 34
Long Answer Questions: 23

Competition File
Some more important reactions
Typical questions
I. IUPAC Nomenclature a to o
II Conversions a to p
III. Questions based on structure 1 to 11
IV. Complete the reactions a to q
V. Other Questions 14
Objective Questions: Multiple choice questions: 55
Fill in the blanks: 15
True or False: 8

Carboxylic acids and their derivatives

14 B.1 Carboxylic acids and
14 B. 2 Nomenclature of Carboxylic acids
14 B. 3 Preparation of Carboxylic acids
P.P. 14 B.5 to 14B.8
14 B.4 Physical properties of Carboxylic acids
14 B.5 Chemical properties of Carboxylic acids
14 B.6 Some Commercially important Carboxylic acids
14 B.7 Distinction between alcohols, phenols and Carboxylic acids
14 B.8 Distinction between some pairs (Chemical tests)
P.P. 14B.9 to 14B.15

Functional derivatives of Carboxylic acids

14 B.9 Functional derivatives of Carboxylic acids
14 B. 10 Acyl halides
14 B. 11 Acid anhydrides
14 B. 12 Esters
14 B. 13 Acid Amides
14 B. 14 Some Commercially important compounds







Conceptual Questions: 1 to 15

Additional Numerical Problems for Practice:
Revision Exercises
Very Short Answer questions : 23
Short Answer Questions : 31
Long Answer Questions : 16

Competition File
Typical questions
I Conversions I (i) to (iv) 2. (a) to (o)
II. Complete the reactions 1. (a) to (m)
III. Questions based on structure 1 to 8
IV. Other Questions 1 to 8

Numerical Problems
Objective Questions: Multiple questions: 48
Fill in the blanks: 10
True or False: 10

Study Plan

Day 1
Part A: Aldehydes and Ketons

14A.1 Nomenclature of aldehydes and ketones
14.2 Isomerism in aldehydes and ketones
Practice Problems 14A.1 to 14A. 6

Day 2

14.3 General methods of preparation of aldehydes and ketones
P.P 14A.7 to 14A.12

Day 3 &4

14.4 Physical properties of aldehydes and ketones
14.5 Chemical properties of aldehydes and ketones
P.P. 14A.13 to 14A.20

Day 5

14.6 Commercially important carbonyl compounds
14.7 Distinction between properties of aldehydes and ketones
14.8 Distinction between some pairs (Chemical tests)

Day 6

Conceptual Questions 12
Revision Exercises: Very Short Answer questions : 31

Day 7

Revision Exercises: Short Answer Questions : 34


Day 8


Carboxylic acids and their derivatives

14 B.1 Carboxylic acids and
14 B. 2 Nomenclature of Carboxylic acids
P.P. 14B.1 to 14B.4

Day 9

14 B. 3 Preparation of Carboxylic acids
P.P. 14 B.5 to 14B.8
14 B.4 Physical properties of Carboxylic acids

Day 10

14 B.5 Chemical properties of Carboxylic acids
14 B.6 Some Commercially important Carboxylic acids
14 B.7 Distinction between alcohols, phenols and Carboxylic acids
14 B.8 Distinction between some pairs (Chemical tests)

Day 11

P.P. 14B.9 to 14B.15

Functional derivatives of Carboxylic acids

14 B.9 Functional derivatives of Carboxylic acids
14 B. 10 Acyl halides

Day 12
14 B. 11 Acid anhydrides

Dah 13
14 B. 12 Esters

Day 14
14 B. 13 Acid Amides

Day 15
14 B. 14 Some Commercially important compounds



Revision Period

Day 16

14B - Conceptual Questions: 1 to 15

Day 17
14B - Revision Exercises: Very Short Answer questions : 23

Day 18

14B - Revision Exercises: Short Answer Questions : 1 to 15

Day 19
14B - Revision Exercises: Short Answer Questions : 16 to 31


Day 20



14A Competition File: Some more important reactions
14A Competition File: Typical questions I. IUPAC Nomenclature a to o

Day 21
14A Competition File: Typical questions II Conversions a to p
Day 22
14A Competition File: Typical questions III. Questions based on structure 1 to 11
Day 23
14A Competition File: Typical questions IV. Complete the reactions a to q
Day 24
14A Competition File: Typical questions V. Other Questions 14

Day 25
14A Objective Questions: Multiple choice questions: 1to 25
Day 26
14A Objective Questions: Multiple choice questions: 26 to 55

Day 27
14AFill in the blanks: 15
14ATrue or False: 8



Day 28
14B - Competition File: Typical questions - I Conversions I (i) to (iv) 2. (a) to (o)

Day 29
14B - Competition File: Typical questions - II. Complete the reactions 1. (a) to (m)

Day 30
14B - Competition File: Typical questions - III. Questions based on structure 1 to 8

Special task (Four half hours)
14B - Competition File: Typical questions - IV. Other Questions 1 to 8

14B - Objective Questions: Multiple questions: 1 to 24
14B - Objective Questions: Multiple questions: 25 to 48

14B Fill in the blanks: 10
14B True or False: 10

Carboxylic Acids - Physical Properties - Revision Points

a. Physical state and smell

The first three members are colourless liquids and have pungent smell. The next six members are oily liquids with a faint unpleasant odour.

Still higher acids are colourless waxy solids.

Benzoic acids and its homologues are colourless solids.

b. Boiling points

They have higher boiling points than the corresponding alcohols of comparable molecular masses.

Carboxylic acids have higher boiling points due to the presence of intramolecular hydrogen bonding. Due to the hydrogen bonding, carboxylic acids exist as dimers.

c. Melting point

In the case of first ten carboxylic acids, the melting points of acids containing even number of carbon atoms is higher than the next lower and higher member containing odd number of carbon atoms.

The melting and boiling points of aromatic acids are usually higher than those of aliphatic acids of comparable molecular masses.

d. Solubility in water

The first four members of aliphatic carboxylic acids are very soluble in water. The solubility in water decreases gradually with rise in molecular mass. All are soluble in alcohol or ether.

Benzoic acid is sparingly soluble in cold water but is soluble in hot water, alcohol and ether.

Carboxylic Acids- Study Guide - IIT JEE

Preparation, properties and reactions

Characteristic reactions of
formation of esters, acid chlorides and amides, ester hydrolysis;

Nomenclature - Carboxylic Acids

Nomenclature


The common names of carboxylic acids are based on their source of origin. Formic acid was first obtained from red ants (Latin formica means red ants) and it was named from that. Acetic acid was obtained from vinegar (Latin aceum means vinegar) and so got that name.

In the common system the position of substituents is indicated by the Greek letters α, β, γ, ō.

α, β, γ, ō Carbon atoms

The carbon atom next to the carboxyl carbon is assigned the letter α. The carbon next to α-carbon is the β-carbon. The carbon next to β-carbon is the γ-carbon. The carbon next to γ-carbon is the ō Carbon.

ō-γ-β-α carbons
C-C-C-C-COOH


IUPAC System

According to IUPAC system, the name of the monocarboxylic acid is derived by changing the final 'e' from the name of the corresponding hydrocarbon with 'oic' and adding the word acid.

Formic acid - Methanoic acid
Acetic acid - Ethanoic acid
n-Butyric acid - Butanoic acid
Isobutyric acid - 2-Mehtylpropanoic acid

Dicarboxylic acids

Oxalic acid - Ethanedioic acid
Malonic acid - Propanedioic acid

The position of substituents is indicated by the following rules.

1. The longest chain of carbon atoms containing the carboxylic group(-COOH) is selected.
2. The numbering of carbons starts from the carboxylic acid group and the carbon of carboxyl group is given number 1.
3. The position of the substituents is indicated by the number of carbon atom to which they are attached.



Aromatic carboxylic acids

The simplest aromatic carboxylic acid is benzoic acid.

The IUPAC names of substituted aromatic carboxylic acids are derived by prefixing the name of the substituent to the name of the parent acid i.e., benzoic acid and the position is indicated by an Arabic numeral with the carbon atom carrying the –COOH group being numbered as 1.

Carboxylic acids - introduction

1. Carboxylic acids are the compound containing carboxyl group in their molecules.

-C with a double bond with oxygen and single bond with OH

2. These acides can be aliphatic or aromatic.

aliphatic acids:

Formic acid HCOOH
Acetic acid CH-3COOH
Isobutyric acid (Branched)

aromatic acids

Bezoic acid : H in benzene substituted by COOH

m-Nitrobenzoic acid: One more H substituted by NO-2

o-Toluic acid (o refers to ortho) Benzoic acid with one more H substituted by CH-3

Both aliphatic and aromatic carboxylic acids are further classified as mono, di, tricarboxylic acids depending upon the number of carboxylic groups present in their molecules.

Some dicarboxylic acids

Oxalic acid COOOH-COOH
Malonic acd CH2(COOH)2
Succinic acid (CH2COOH)2
Phthalic acid is an aromatic dicarboxylic acid Ar(COOH)2. 2nd COOH is in ortho position
Phthalic acid come in the amines, as primary amines are prepared from Phthalimide using Gabriel's phthalimide synthesis.
Isophthalic acid (2nd COOH in meta position)
Terephtalic acid (2nd COOH in para position)


Nomenclature

According to IUPAC system, the name of the monocarboxylic acid is derived by changing the final 'e' from the name of the corresponding hydrocarbon with 'oic' and adding the word acid.

Formic acid - Methanoic acid
Acetic acid - Ethanoic acid
n-Butyric acid - Butanoic acid
Isobutyric acid - 2-Mehtylpropanoic acid

Dicarboxylic acids

Oxalic acid - Ethanedioic acid
Malonic acid - Propanedioic acid

Methods of Preparation of Monocarboxylic Acids

Methods of Preparation of Monocarboxylic Acids:

1. From oxidation of primary alcohols
Primary alcohols are oxidized with potassium permanganate or potassium dichromate to aldehydes which on further oxidation give carboxylic acids.

2. By oxidation of aldehydes and ketones.
This method is already part method 1.
Aldehydes are easily oxidised to carboxylic acids even with mild oxidising agents like Tollen's reagent.

3. From hydrolysis of nitriles and cyanides
the nitriles are hydrolysed in dilute acqueous acidic or alkaline medium.

4. From Grignard reagents
The reaction is carried out by bubbling CO2 through th etheral solution of suitable Grignard reagent.

5. By hydrolysis of esters
Hydrolysis of esters with mineral acids or alkalines gives carboxylic acids

6. Carboxylaiton of alkenes
Heating alkenes with CO and steam under pressure with phospoiric acid at 673 K. This reaction is called Koch reaction.

7. From trihalogen derivatives of hydrocarbons
Hydroysis of 1,1,1,-trihalogen derivatives of alkanes with acqueous KOH.

8. Preparation of aromatic acids from alkyl benzenes
the alkyl side cahin of benzene ring can be easily oxidized to carboxylic group iwth alkalines KMnO4, chromic anhydride or conc. HNO3.

Carboxylic acids - Characteristic reactions

Grouping of the reactions

A. Reactions due to hydrogen atom of carboxyl group
B. Reactions due to OH part of carboxyl group
C. Reactions due to carboxyl group
D. Reactions due to alkyl group and benzene ring



A. Reactions due to hydrogen atom of carboxyl group

1. Acidic character

a. Action with blue litmus
all carboxylic acids turn blue litmus red.


b. Reaction with metals: liberation of hydrogen
Carboxylic acids react with active metals such as Na, K, Ca, Mg, Zn, etc., to form their salts with the liberation of hydrogen.

c. Action with alkalies: formation of salts
Carboxylic acids neutralize alkalies forming salts and water.

d. Action with carbonates and bicarbonates: evolving carbon dioxide
Carboxylic acids decompose carbonates and bicarbonates evolving carbon dioxide with brisk effervescence.


Mechanism of acidic character


In the COOH group due to resonance in the OH, O acquires some positive charge the electron pair of OH is drawn towards O. This displacement of electrons causes the release of a proton and a carboxylate ion, RCOO- is formed. This is the reason for acidic character of carboxylic acids.

The strength of acids can be expressed in terms of dissociation constant Ka or Ph number of PKa number which is pKa = -log Ka

A stronger acid will have a higher Ka value but smaller PKa value.

Effects of substituents on acidic strength of acids

Electron releasing substituents: Alkyl is an electron releasing group. If the H atom of formic acid (HCOOH) is replaced by CH3 group to form acetic acid (CH3COOH) the alkyl group will tend to increase the electron density on the oxygen atom of the O-H bond. This increase will make removal H+ ion difficult in comparison to formic acid.

Acetic acid is a weaker acid in comparison to formic acid.

The electron release effect is called +I effect. As +I effect increases, acidic strength will go down. As more alkyl groups are there +I effect increases
CH3
Therefore acidic property is stronger or more for CH3COOH.

Acidic strength is in the following order
acidic strength of HCOOH>CH3COOH>CH3CH2COOH>(CH3)2CHCOOH

Electron withdrawing substituents: Substituents like halogens tend to withdraw the electron charge. Halogens are electron attracting atoms(-I inductive effect). They withdraw the electrons from the carbon to which they are attached and this effect is transmitted throught the chain. The increases positive charge on O atom in the O-H bond and dissociation of H+ ion or proton takes place more easily.

Hence chloroacetic acid is stronger acid than acetic acid.





B. Reactions due to OH part of carboxyl group

The -OH group of carboxylic acids can be replaced by a number of groups such as, -Cl, -NH2, OR, -OOCR’ to form chlorides, amides, esters ad anhydrides.


Formation of acid chlorides
Acetic acid + PCl5  Acetyl chloride + POCL3 + HCl

Formation of esters
When carboxylic acids are heated with alcohols in the presence of concentrated sulphuric acid, esters are formed.

Formation of amides
Carboxylic acids react with ammonia to form ammonium salts.
Acetic acid + Ammonia  Ammonium acetate
Ammonium acetate on heating gives acetamide plus water.

Formation of acid anhydrides
Carboxylic acids on heating in the presence of a strong dehydrating agent such as phosphorous pentoxide form acid anhydrides.


C. Reactions due to carboxyl group

Decarboxylation:
Salts of carboxylic acids get decarboxylated – lose carbon dioxide in some reactions.

a. Sodium or potassium salts of carboxylic acids on heating with soda lime give alkanes.
b. Electrolysis of acqueous solutions of sodium or potassium salts of carboxylic acids gives alkanes due to decarboxylation.
c. When calcium salts of monocarboxylic acids (fatty acids) are heated aldehydes or ketones are formed.


Reduction
a. Partial reduction: Carboxylic acids on reduction with lithium aluminium hydride or with hydrogen in the presence of copper chromite are reduced to alcohols.
b. Complete reduction to alkanes: Carboxylic acids on reduction with HI and red P give alkanes.


Action of bromine on silver salt of acid:
The silver saltsof the carboxylic acid on treatment with Br2 in the presence of CCl4 give alkyl halides having one carbon atom less than the parent acid.

This reaction is called Hunsdiecker reaction.

D. Reactions due to alkyl group and benzene ring

Halogenation
Carboxylic acids react with chlorine on bromine in the presence of a small amount of phosphorus to give halogenated compounds. The reaction is called Hell Volhard-Zelinksy reaction.

Ring substitution in aromatic acids:
In substitution reactions with aromatic carboxylic acids, carboxyl group is an electron withdrawing group and therefore it favours meta position for the substituent.

Hence benzoinc acid + bromine gives 3-Bromobenzoic acid

Formation of esters

Esters are compounds which are formed when the hydroxy hydrogen atom in oxygen acids is replaced by an alkyl group. The acid may be organic or inorganic.

Esters of organic acid:
These are compounds formed by replacing the hydrogen atom of the carboxyl group by an alkyl group.

In -COOH of carboxylic acids H is replaced an alkyl group.

It may be represented as R-COOH-R'.

Acetic acid + Ethanol ---> Ethyl acetate (Ethyl ethanoate) + water

Ethyl acetate (Ethyl ethanoate) is ester CH3COOC2H5

When a carboxylic acid is heated with an alcohol in presence of dehydrating agent like concentrated sulphuric acid , it gives an ester.

carboxylic acid chlorides

Carboxylic acids can be converted into acid chlorides by treatment with phosphorous chlorides (PCl5, Pcl3) or thionyl chloride (SOcl2) in pyridine.

Acetic acid + Phosphorous Pentachloride = Acetyl chloride + POCl3 + HCL

acetic acid + PCl3 = Acetyl chloride + HePO3

acetic acid + thionyl chloride = acetyl chloride + sulphur dioxide + HCl

From benzoic acid we get benzoyl chloride

Ch.28 Carboxylic Acid - Ester Hydrolysis

Ester hydrolysis

Hydrolysis of Esters

Esters are hydrolysed water and the process is accelerated by dilute mineral acids (HCL or H2SO4) or alkalies.

Ethyl acetate + water  gives Acetic acid + Ethyl alcohol (in the presence of dilute mineral acid)

Ethyl acetate + Sodium hydroxide (alkali)  Sodium acetate + Ethyl alcohol

Acidic hydrolysis is reversible.

Alkaline hydrolysis is irreversible because resonance stabilized carboxylate (acetate ion is formed and it has very little tendency to react with an alcohol.

Hydrolysis of esters by alkalies is known as saponification. Saponification leads to the formation of soaps. It is a very rapid reaction as alkali acts as catalyst and also as a reactant.

Mechanism of alkaline hydrolysis of esters.

Step I. the nucleophile, OH ¯ ion from the alkali attacks the carboxyl carbon to form an intermediate

Step II the intermediate, then loses a molecule of ethoxide ion to form acetic acid .

Step III. Ethoxide ion then removes a proton from acetic acid and thus acetate ion is formed.

Step IV. This acetate ion combines with Na+ to form Sodium acetate.

Ch.28 Carboxylic Acid - Core Points for Revision

JEE syllabus

Carboxylic acids:
Preparation, properties
Characteristic reactions
formation of esters,
acid chlorides and amides,
ester hydrolysis;
---------
1. Carboxylic acids are the compound containing carboxyl group in their molecules.

-C with a double bond with oxygen and single bond with OH

2. These acides can be aliphatic or aromatic.

aliphatic acids:

Formic acid HCOOH
Acetic acid CH-3COOH
Isobutyric acid (Branched)

aromatic acids

Bezoic acid : H in benzene substituted by COOH

m-Nitrobenzoic acid: One more H substituted by NO-2

o-Toluic acid (o refers to ortho) Benzoic acid with one more H substituted by CH-3

3. Methods of Preparation of Monocarboxylic Acids:
1. From oxidation of primary alcohols
2. By oxidation of aldehydes and ketones.

4.

Study Guide TMH JEE Ch.28 Carboxylic Acid

JEE syllabus

Carboxylic acids:
Preparation, properties
Characteristic reactions
formation of esters,
acid chlorides and amides,
ester hydrolysis;

----------
Main Topics Covered in the TMH Book

METHODS OF PREPARATION
PHYSICAL PROPERTIES
CHEMICAL REACTIONS
FUNCTIONAL DERIVATIVES OF CARBOXYLIC ACIDS

------------------



Carboxylic acids are the compound containing carboxyl group in their molecules.

-c with a double bond with oxygen and single bond with OH


The carboxyl group is made up of carbonyl C with double bond with oxygen, and hydroxyl group OH. The carboxyl is formed carbo + oxyl.

These acides can be aliphatic or aromatic.

aliphatic acids

Formic acid HCOOH
Acetic acid CH-3COOH
Isobutyric acid (Branched)

aromatic acids

Bezoic acid : H in benzene substituted by COOH

m-Nitrobenzoic acid: One more H substituted by NO-2

o-Toluic acid (o refers to ortho) Benzoic acid with one more H substituted by CH-3

Dicarboxyic acids

Oxalic acid
Malonic acid
Succinic acid
Phthalic acid - It is an aromatic carboxylic acid

In the nomenclature, in common system, position of the sustituents is indicated by the greek letter alpha, beta, gamma and delta.

the carbon atom adjacent ot the carboxyl carbon is assigned the letter α, thenext carbon on chain is beta an so on.

According to the IUPAC system, the name of the acid is derived from the corresponding alkane by replacing the terminal 'e' with the '-oic' and adding the word acid.

The position of the substituents is indicated by the following rules:
1. The longest chain containing the carboxylic group (-COOH) is selected.
2. The carbon chain is numbered form the carboxylic acid group. The carbon of carboxyl group is always given number one.
3. The position of the substituents is indicated by the number.

Methods of Preparation of Monocarboxylic Acids:
1. From oxidation of primary alcohols
2. By oxidation of aldehydes and ketones.
3. By Hydrolysis of cyanides (or Nitriles)
4. By Grignard reaction
5. By hydrolysis of esters
6. By carboxylation of alkenes
7. From trihalogen derivatives of hydrocarbons
8. Aromatic acids from alkyl benzenes

Physical properties

State
B.P.
M.P.
Solubility


Reactions of carboxylic Acids

covered under the following heads

A. reactions due to hydrogen atom of carboxyl group
B. reactions due to OH carboxyl group
C. reactions due to carboxyl group
D. reactions due to alkyl group and benzene ring.


A. reactions due to hydrogen atom of carboxyl group

1. Acidic Properties

B. reactions due to OH carboxyl group
1. Formation of an acid anhydride
2. Formation of Esters (specially mentined in JEE syllabus)
3. Formation of amides (specially mentined in JEE syllabus)
4. Formation of acid chlorides (specially mentined in JEE syllabus)

C. reactions due to carboxyl group
1. Decarboxylation
2. Reduction
3. Action of bromine on silver salt of the acid
D. reactions due to alkyl group and benzene ring.
1. Halogenation
2. Ring substitution in aromatic acids

Ester hydrolysis (specially mentined in JEE syllabus) (from jauhar's book section on esters page 806)
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web sites
www.goiit.com/chapters/tutorial/chemistry/carboxyllic_acid.htm