Sections in the chapter spread over three parts
Part A Nitro compounds
15A.1 Nomenclature of nitro compounds
15.2 Preparation of nitro compounds
15.3 Physical properties of nitro compounds
15.4 Chemical properties of nitro compounds
15.5 Uses of nitro compounds
15.6 Distinction between nitroalkanes and alkyl nitrites
15.7 Some commercially important compounds
Conceptual Questions with Answers: 6
Revision Exercises: Very Short Answer questions 20
Short Answer Questions : 30
Long Answer Questions : 8
Competition File
Typical questions
Conversions: 2
Numerical Problems
Objective Questions: Multiple choice 15
Fill in the blanks: 5
True or False: 5
Part B Amines
15B.1 Nomenclature of amines
15.2 Isomerism in amines
15B.3 Preparation of amines
15B.4 Industrial Preparation of amines
15B.5 Physical properties of amines
15B.5B Chemical properties of amines
15B.6 Distinction between primary, secondary and tertiary amines
15B.7 Separation of mixture of primary, secondary and tertiary amines
15B.8 Some commercially important compounds
15B.9 Distinction between pairs of compounds
Conceptual Questions with Answers: 16
Revision Exercises
Very Short Answer questions: 30
Short Answer Questions: 48
Long Answer Questions : 25
Competition File
Typical questions
I. Conservsions: 3
II. Questions based on structure 3
III. Complete the reactions 2
IV. Other questions 13
Numerical Problems
Objective Questions: Multiple choice 40
Fill in the blanks: 10
True or False: 10
Part C. Cyanides and Isocyanides & Diazonium salts
Cyanides and Isocyanides
15C.1 Nomenclature of Cyanides and Isocyanides
15.2 Preparation of Cyanides and Isocyanides
15.3 Physical properties of Cyanides and Isocyanides
15.4 Chemical properties of Cyanides and Isocyanides
15.5 Uses of Cyanides and Isocyanides
15.6 Distinction between cyanide and ethyl isocyanide
Practice Problems 15C.1 to 15C.4
Diazonium salts
15.7 Nomenclature Diazonium salts
15.8 Preparation of Diazonium salts
15.9 Physical properties of Diazonium salts
15.10 Chemical properties of Diazonium salts
15.11 Importance of Benzene Diazonium salts in synthetic organic chemistry
Conceptual Questions with Answers: 4
Additional Numerical Problems for Practice:
Revision Exercises
Very Short Answer questions : 20
Short Answer Questions : 28
Long Answer Questions 5
Competition File
Typical questions
I. Conservsions: 1
II. Questions based on structure 2
Objective Questions: Multiple choice 10
Fill in the blanks: 5
True or False: 5
Study Plan
Part A Nitro compounds
Day 1
15A.1 Nomenclature of nitro compounds
15.2 Preparation of nitro compounds
15.3 Physical properties of nitro compounds
Practice problems 15A.1 to 15A.4
Day 2
15.4 Chemical properties of nitro compounds
15.5 Uses of nitro compounds
15.6 Distinction between nitroalkanes and alkyl nitrites
Day 3
15.7 Some commercially important compounds
Conceptual Questions with Answers: 6
Revision Exercises: Very Short Answer questions 20
Day 4
Short Answer Questions : 30
Day 5
Competition File
Typical questions
Conversions: 2
Numerical Problems
Objective Questions: Multiple choice 15
Fill in the blanks: 5
True or False: 5
Day 6
Part B Amines
15B.1 Nomenclature of amines
15.2 Isomerism in amines
15B.1 to 15B.3
Day 7
15B.3 Preparation of amines
15B.4 Industrial Preparation of amines
15B.5 Physical properties of amines
Day 8
15B.5B Chemical properties of amines
Day 9
15B.6 Distinction between primary, secondary and tertiary amines
15B.7 Separation of mixture of primary, secondary and tertiary amines
15B.8 Some commercially important compounds
15B.9 Distinction between pairs of compounds
Day 10
Conceptual Questions with Answers: 16
Revision Exercises: Very Short Answer questions: 30
Day 11
Part C. Cyanides and Isocyanides & Diazonium salts
Cyanides and Isocyanides
15C.1 Nomenclature of Cyanides and Isocyanides
15.2 Preparation of Cyanides and Isocyanides
15.3 Physical properties of Cyanides and Isocyanides
Day 12
15.4 Chemical properties of Cyanides and Isocyanides
15.5 Uses of Cyanides and Isocyanides
15.6 Distinction between cyanide and ethyl isocyanide
Practice Problems 15C.1 to 15C.4
Day 13
Diazonium salts
15.7 Nomenclature Diazonium salts
15.8 Preparation of Diazonium salts
15.9 Physical properties of Diazonium salts
15.10 Chemical properties of Diazonium salts
15.11 Importance of Benzene Diazonium salts in synthetic organic chemistry
Day 14
Conceptual Questions with Answers: 4
Revision Exercises: Very Short Answer questions : 20
Day 15
15B (Amines): Short Answer Questions: 48
Revision Peirod
Day 16
15B (Amines): Competition File
Typical questions
I. Conservsions: 3
II. Questions based on structure 3
Day 17
15B (Amines): Competition File
Typical questions
III. Complete the reactions 2
IV. Other questions 13
Day 18
Objective Questions: Multiple choice 1 to 20
Day 19
Objective Questions: Multiple choice 21 to 40
Day 20
Fill in the blanks: 10
True or False: 10
Day 21
15c (Diazonium salts): Conceptual Questions with Answers: 4
Concept revision
Day 21
15c (Diazonium salts): Revision Exercises: Very Short Answer questions : 20
Day 22
15c (Diazonium salts): Revision Exercises: Short Answer Questions : 28
Day 23
Competition File
Typical questions
I. Conservsions: 1
II. Questions based on structure 2
Day 24
Objective Questions: Multiple choice 10
Fill in the blanks: 5
True or False: 5
Day 25 to 30
Concept revision and test paper questions
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Rabu, 11 Maret 2009
Sabtu, 27 Desember 2008
Amines- Study Guide - IIT JEE
Preparation, properties and reactions
Characteristic reactions of Amines
basicity of substituted anilines and aliphatic amines, preparation from nitro compounds, reaction with nitrous acid, azo coupling reaction of diazonium salts of aromatic amines, Sandmeyer and related reactions of diazonium salts; carbylamine reaction
Characteristic reactions of Amines
basicity of substituted anilines and aliphatic amines, preparation from nitro compounds, reaction with nitrous acid, azo coupling reaction of diazonium salts of aromatic amines, Sandmeyer and related reactions of diazonium salts; carbylamine reaction
Rabu, 20 Februari 2008
Glossary -Amines -for IIT JEE
AMIDES
"amide" is for the CONH2 or CONR2(more general) bond system at the end of the carbon chain
PRIMARY ACID AMIDES
The primary suffix name for an aliphatic acid amide is based on the "longest carbon chain name (without e)" + "amide" for the CONH2 bond system at the end of the carbon chain e.g. methanamide, ethanamide etc. There are two hydrogens on the N of the amide group.
SECONDARY ACID AMIDES
These have one hydrogen and one alkyl or aryl group on the N of the amide group.
TERTIARY ACID AMIDES
These have two alkyl or aryl groups attached to the N of the amide group.
POLYAMIDES and POLYPEPTIDES are secondary amides formed in a condensation reaction between a carboxylic acid and an amine. Water is eliminated between the two 'monomers' to give the secondary, polyamide (polymer) or polypeptide ( in proteins) linkage
AminesAmines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.
Carbylamine reaction
The treatment of a primary amine with chloroform and alcoholic potash produces carbylamine (isocyanide) which has most offensive smell. This reaction is not exhibited by secondary and tertiary amines.
"amide" is for the CONH2 or CONR2(more general) bond system at the end of the carbon chain
PRIMARY ACID AMIDES
The primary suffix name for an aliphatic acid amide is based on the "longest carbon chain name (without e)" + "amide" for the CONH2 bond system at the end of the carbon chain e.g. methanamide, ethanamide etc. There are two hydrogens on the N of the amide group.
SECONDARY ACID AMIDES
These have one hydrogen and one alkyl or aryl group on the N of the amide group.
TERTIARY ACID AMIDES
These have two alkyl or aryl groups attached to the N of the amide group.
POLYAMIDES and POLYPEPTIDES are secondary amides formed in a condensation reaction between a carboxylic acid and an amine. Water is eliminated between the two 'monomers' to give the secondary, polyamide (polymer) or polypeptide ( in proteins) linkage
AminesAmines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.
Carbylamine reaction
The treatment of a primary amine with chloroform and alcoholic potash produces carbylamine (isocyanide) which has most offensive smell. This reaction is not exhibited by secondary and tertiary amines.
Sabtu, 26 Januari 2008
IIT JEE Revision - Ch 30 Amines - Core Points
JEE Syllabus
Amines:
Preparation, Properties, Reactions
Characteristic reactions
Basicity of substituted anilines and aliphatic amines,
Preparation from nitro compounds,
Reaction with nitrous acid,
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
Carbylamine reaction;
Amines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.
Preparation from nitro compounds,
Reduction of nitro compound to obtain amine can be done by using either molecular hydrogen and a catalyst (Ni or Pt) or a metal (usually granulated tin) and an acid (HCl)
Reaction with nitrous acid,
Aliphatic primary amine in reactin with nitrous acid forms unstable diazonium salt which on decomposing liberates nitrogen and mixture of alcohols and alkenes.
Basicity of substituted anilines and aliphatic amines,
Nitrogen of amines contains lone pair of electrons, which can be shared with other species and thus these act as Lewis bases.
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
The diazonium salt is treated with cuprous chloride or cuprous bromide.
Carbylamine reaction;
The treatment of a primary amine with chloroform and alcoholic potash produces carbylamine (isocyanide) which has most offensive smell. This reaction is not exhibited by secondary and tertiary amines.
Amines:
Preparation, Properties, Reactions
Characteristic reactions
Basicity of substituted anilines and aliphatic amines,
Preparation from nitro compounds,
Reaction with nitrous acid,
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
Carbylamine reaction;
Amines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.
Preparation from nitro compounds,
Reduction of nitro compound to obtain amine can be done by using either molecular hydrogen and a catalyst (Ni or Pt) or a metal (usually granulated tin) and an acid (HCl)
Reaction with nitrous acid,
Aliphatic primary amine in reactin with nitrous acid forms unstable diazonium salt which on decomposing liberates nitrogen and mixture of alcohols and alkenes.
Basicity of substituted anilines and aliphatic amines,
Nitrogen of amines contains lone pair of electrons, which can be shared with other species and thus these act as Lewis bases.
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
The diazonium salt is treated with cuprous chloride or cuprous bromide.
Carbylamine reaction;
The treatment of a primary amine with chloroform and alcoholic potash produces carbylamine (isocyanide) which has most offensive smell. This reaction is not exhibited by secondary and tertiary amines.
IIT JEE Revision Amines - Introduction - Classification
Amines are derivatives of ammonia
Primary
Secondary
Tertiary
Aliphatic
Aromatic
Simple and Mixed
Primary
Secondary
Tertiary
Aliphatic
Aromatic
Simple and Mixed
IIT JEE Revision - Amines Nomenclature
Nomenclature of aliphatic amines
Common system:
In the common system, amines are called alkylamines. The suffix amines is added to the name of the corresponding alkyl group.
Ex: Methylamine, Ethylamine, Propylamine
Second common system
In the second system of the common system, primary amines are named as the amino derivatives of the corresponding hydrocarbons and are names as aminoalkanes. The position of the amino group is indicated by Arabic numeral. The numbering of the primary chain is to be done in such a way that the carbon atom containing the amino group gets the lowest possible number.
Secondary and tertiary amines are named as nitrogen substituted primary amine.
Example: N-Methylaminoethane
Primary amine is aminoethane and N-Methyl is added to it. N- indicates that the methyl group is attached to the nitrogen atom.
IUPAC system
The aliphatic amines are called alkamines. The letter ‘e’ in the alkane is replaced by suffix amine.
Ex: methanamine, ethanamine
The position of the amino group is indicated by Arabic numeral. The numbering of the primary chain is to be done in such a way that the carbon atom containing the amino group gets the lowest possible number.
Ex: 1-propanamine, 2-propanamine
Aromatic Amines
Common system
Aromatic amines are called aryl amines. Suffix amine is added to the aryl group.
IUPAC System
The simplest aromatic amine C6H5NH2 is called benzanamine.
Other aromatic amines are named as derivatives of benzenamine and positions of other groups are indicated by numbers
Ex: Benzenamine
N-Methylbenzenamine, N,N-Dimethylbenzenamine, 2-Methylbenzenamine, 3-Methylbenzenamine
In IUPAC system, benzenamine may also be written as amino benzene.
Common system:
In the common system, amines are called alkylamines. The suffix amines is added to the name of the corresponding alkyl group.
Ex: Methylamine, Ethylamine, Propylamine
Second common system
In the second system of the common system, primary amines are named as the amino derivatives of the corresponding hydrocarbons and are names as aminoalkanes. The position of the amino group is indicated by Arabic numeral. The numbering of the primary chain is to be done in such a way that the carbon atom containing the amino group gets the lowest possible number.
Secondary and tertiary amines are named as nitrogen substituted primary amine.
Example: N-Methylaminoethane
Primary amine is aminoethane and N-Methyl is added to it. N- indicates that the methyl group is attached to the nitrogen atom.
IUPAC system
The aliphatic amines are called alkamines. The letter ‘e’ in the alkane is replaced by suffix amine.
Ex: methanamine, ethanamine
The position of the amino group is indicated by Arabic numeral. The numbering of the primary chain is to be done in such a way that the carbon atom containing the amino group gets the lowest possible number.
Ex: 1-propanamine, 2-propanamine
Aromatic Amines
Common system
Aromatic amines are called aryl amines. Suffix amine is added to the aryl group.
IUPAC System
The simplest aromatic amine C6H5NH2 is called benzanamine.
Other aromatic amines are named as derivatives of benzenamine and positions of other groups are indicated by numbers
Ex: Benzenamine
N-Methylbenzenamine, N,N-Dimethylbenzenamine, 2-Methylbenzenamine, 3-Methylbenzenamine
In IUPAC system, benzenamine may also be written as amino benzene.
IIT JEE Revision - Amines - Isomerism
1. Chain
Aliphatic amines containing four or more carbon atoms show chain isomerism as branched and straight chain alkyl groups can be attached to the nitrogen atom.
Example: Butan-1-amine, 2-Methylpropan-1-amine, and 2 Methylpropan-2-amine are chain isomers.
2. Position Isomerism
The amino group can be bonded to different carbon atoms of the alkyl group.
Example: Propan-1-amine and Propan-2-amine
3. Functional
Primary, secondary and tertiary amines having the same molecular formula are isomers. This isomerism is functional isomerism because different alkyl groups (functional groups) are present in the molecules and give rise to isomerism
4. Metamerism
In amines metamerism, a type of isomerism in which different alkyl groups are attached to the Nitrogen atom of the amino group exists(molecular formula for isomers is same).
Example: Diethylamine, Methyl-n-propylamine, and Isopropylmethylamine are metamers.
5. Chiral amines
Nitrogen atom undergoes sp3 hybridisation. Hence secondary and tertiary amines have a chiral nitrogen atom. But chiral amines cannot be resolved. This is because the two enantiomeric forms rapidly interconvert and it is very difficult to isolate a pure sample of either enantiomer.
Aliphatic amines containing four or more carbon atoms show chain isomerism as branched and straight chain alkyl groups can be attached to the nitrogen atom.
Example: Butan-1-amine, 2-Methylpropan-1-amine, and 2 Methylpropan-2-amine are chain isomers.
2. Position Isomerism
The amino group can be bonded to different carbon atoms of the alkyl group.
Example: Propan-1-amine and Propan-2-amine
3. Functional
Primary, secondary and tertiary amines having the same molecular formula are isomers. This isomerism is functional isomerism because different alkyl groups (functional groups) are present in the molecules and give rise to isomerism
4. Metamerism
In amines metamerism, a type of isomerism in which different alkyl groups are attached to the Nitrogen atom of the amino group exists(molecular formula for isomers is same).
Example: Diethylamine, Methyl-n-propylamine, and Isopropylmethylamine are metamers.
5. Chiral amines
Nitrogen atom undergoes sp3 hybridisation. Hence secondary and tertiary amines have a chiral nitrogen atom. But chiral amines cannot be resolved. This is because the two enantiomeric forms rapidly interconvert and it is very difficult to isolate a pure sample of either enantiomer.
IIT JEE Revision Preparation of Amines
1. Ammonolysis
Hoffmann’s method: When an aqueous or alcoholic solution of ammonia is heated with an alkyl halide at 373 K in a sealed tube, a mixture of three amines (primary, secondary and tertiary) is obtained. It is very difficult to separate the mixture.
2. Gabriel phthalimide synthesis
In this synthesis, phthalimide is treated with alcoholic KOH to give potassium phthalimide.
Potassium phthalimide is treated with alky halide to form N-alkyl phthalimide.
The hydrolysis of N-alkyl phthalimide with 20% HCl under pressure or refluxing with NaOH gives primary amine.
This method can be used for preparing only primary amines.
3. Reduction of nitriles (cyanides)
Nitriles can be reduced to corresponding amines using H2/Raney Li or Pt, LiAlH4 or Na, C2H5OH
When sodium and alcohol are used, the reaction is called Mendius reaction
4. Reduction of isonitriles (isocyanides)
Isonitriles can be reduced to secondary amines using H2/Raney Li or Pt, LiAlH4 or Na, C2H5OH
5. Reduction of amides (Hoffman degradation method)
Amides on treatment with Br2 and KOH give primary amines. The amine formed contains one carbon atom less than the parent amide.
6. Reduction of oximes
Oximes are obtained from aldehydes and ketones by reaction with hydroxylamine. The oximes of aldehydes or ketones can be reduced to primary amines with either Na/CH2H5OH or LiAlH4.
7. Reductive amination of aldehydes and ketones
Reaction between aldehydes or ketones and ammonia results in the formation of imines. Imines are reduced to primary amines with H2, Ni.
Hoffmann’s method: When an aqueous or alcoholic solution of ammonia is heated with an alkyl halide at 373 K in a sealed tube, a mixture of three amines (primary, secondary and tertiary) is obtained. It is very difficult to separate the mixture.
2. Gabriel phthalimide synthesis
In this synthesis, phthalimide is treated with alcoholic KOH to give potassium phthalimide.
Potassium phthalimide is treated with alky halide to form N-alkyl phthalimide.
The hydrolysis of N-alkyl phthalimide with 20% HCl under pressure or refluxing with NaOH gives primary amine.
This method can be used for preparing only primary amines.
3. Reduction of nitriles (cyanides)
Nitriles can be reduced to corresponding amines using H2/Raney Li or Pt, LiAlH4 or Na, C2H5OH
When sodium and alcohol are used, the reaction is called Mendius reaction
4. Reduction of isonitriles (isocyanides)
Isonitriles can be reduced to secondary amines using H2/Raney Li or Pt, LiAlH4 or Na, C2H5OH
5. Reduction of amides (Hoffman degradation method)
Amides on treatment with Br2 and KOH give primary amines. The amine formed contains one carbon atom less than the parent amide.
6. Reduction of oximes
Oximes are obtained from aldehydes and ketones by reaction with hydroxylamine. The oximes of aldehydes or ketones can be reduced to primary amines with either Na/CH2H5OH or LiAlH4.
7. Reductive amination of aldehydes and ketones
Reaction between aldehydes or ketones and ammonia results in the formation of imines. Imines are reduced to primary amines with H2, Ni.
IIT JEE Revision Amines - Preparation from nitro compounds
By reduction of nitro compounds
a. by hydrogen in the presence of Raney Ni, Pt or Pd as catalyst at room temp.
b. with active metals such as Fe, Sn, Zn, and conc. HCl acid
c. with lithium aluminium hydride - LiAlH4
a. by hydrogen in the presence of Raney Ni, Pt or Pd as catalyst at room temp.
b. with active metals such as Fe, Sn, Zn, and conc. HCl acid
c. with lithium aluminium hydride - LiAlH4
IIT JEE Revision Amines - Physical Properties
1. Lower members of the family such as methylamine, dimethylamine, ethylamine are gases at ordinary temperatures and smell like ammonia.
The higher members are mostly liquids haivng fishy smell.
Amines are polar compounds and with the exception of tertiary amines can form intermolecular hydrogen bonds.
Amines hve higher boiling points than non-polar compounds of the same molecular mass.
Amines have lower boiling points than those of alcohols and carboxylic acids.
Primary amines have the highest boiling points and tertiary the lowest.
The lower amines are soluble in water.
Higher amines containing six or more carbon atoms are insoluble.
The amines are also soluble in less polar solvents like ether, alcohol or benzene etc.
The higher members are mostly liquids haivng fishy smell.
Amines are polar compounds and with the exception of tertiary amines can form intermolecular hydrogen bonds.
Amines hve higher boiling points than non-polar compounds of the same molecular mass.
Amines have lower boiling points than those of alcohols and carboxylic acids.
Primary amines have the highest boiling points and tertiary the lowest.
The lower amines are soluble in water.
Higher amines containing six or more carbon atoms are insoluble.
The amines are also soluble in less polar solvents like ether, alcohol or benzene etc.
Jumat, 25 Januari 2008
IIT JEE Revision Amines-Chemical Reactions
Amines Chapter
Characteristic Reactions or Chemical Properties
1. Reaction with water (Basic character of amines) (specially mentioned in JEE syllabus - Covered in more detail in a separate post)
2. Reaction with acids
Amines reacts with acids to form salts. The salts are ionic compounds and are soluble in water.
3. Reaction with metal ions
Amines combine with metal ions such as Ag+ and Cu2+ to form complex ions. The lone pair of electrons in -NH2 group is used to form a coordinate bond with metal ions.
For example, silver chloride dissolves in methylamine to form a soluble silver amine complex.
4. Alkylation
primary and secondary amines react with alkyl halides to form tertiary amines
5. Acylation (reaction with acid chlorides and acid anhydrides)
Primary and secondary amines react with acid chloride or acid anhydride to form substituted amides.
6. Benzoylation
Aliphatic and aromatic amines react with benzoyl chloride in the presence of a base such as pyridine or acqueous NaOH to form benzoyl derivatives in which C6H5CO- group is introduced.
7. schiff's base formation
Both aliphatic and aromatic primary amines react with aldehydes to form Schiff's bases or anils.
8. Oxidation
Primary aliphatic amines on oxidation with potassium permanganate followed by hydrolysis give aldehydes and ketones.
Secondry amines react with Caro's acid to give corresponding N-hydroxy amine.
Tertiary amines are oxidized by Caro's acid, ozone or H2O2 to corresponding N-oxides.
Aninline can be readily oxidized in the presence of K2Cr2O7 and H2SO4, and gives p-benzoquinone.
9. Carbalamine reaction (specially mentioned in JEE syllabus - covered separately)
10. Reaction with nitrous acid (specially mentioned in JEE syllabus - covered separately)
11. Reaction with Grignard reagent
Primary and secondary amines react with Grignard reagents to form alkanes.
Tertiary aliphatic amines do not react with Grignard reagent because they do not have hydrogen atom attached to the nitrogen atom.
12. Carbon disulphide
Primary amines react with carbon disulphide to form dithio-alkyl carbamic acids which decompose on heating with mercuric chloride (HgCl2) to give alkyl isothio cyanates. (Hoffman must oil reaction - a test for primary amines).
13. Carbonyl chloride
Primary and secondary aliphatic amines react with carbonyl chloride to form substituted ureas.
14. Ring substitution in aromatic amines
Aromatic amines give the aromatic substitution reactions as given by benzene.
15. coupling of diazonium salts (specially mentioned in JEE syllabus - covered separately)
16. Sandmeyer and related reactions (specially mentioned in JEE syllabus - covered separately)
Characteristic Reactions or Chemical Properties
1. Reaction with water (Basic character of amines) (specially mentioned in JEE syllabus - Covered in more detail in a separate post)
2. Reaction with acids
Amines reacts with acids to form salts. The salts are ionic compounds and are soluble in water.
3. Reaction with metal ions
Amines combine with metal ions such as Ag+ and Cu2+ to form complex ions. The lone pair of electrons in -NH2 group is used to form a coordinate bond with metal ions.
For example, silver chloride dissolves in methylamine to form a soluble silver amine complex.
4. Alkylation
primary and secondary amines react with alkyl halides to form tertiary amines
5. Acylation (reaction with acid chlorides and acid anhydrides)
Primary and secondary amines react with acid chloride or acid anhydride to form substituted amides.
6. Benzoylation
Aliphatic and aromatic amines react with benzoyl chloride in the presence of a base such as pyridine or acqueous NaOH to form benzoyl derivatives in which C6H5CO- group is introduced.
7. schiff's base formation
Both aliphatic and aromatic primary amines react with aldehydes to form Schiff's bases or anils.
8. Oxidation
Primary aliphatic amines on oxidation with potassium permanganate followed by hydrolysis give aldehydes and ketones.
Secondry amines react with Caro's acid to give corresponding N-hydroxy amine.
Tertiary amines are oxidized by Caro's acid, ozone or H2O2 to corresponding N-oxides.
Aninline can be readily oxidized in the presence of K2Cr2O7 and H2SO4, and gives p-benzoquinone.
9. Carbalamine reaction (specially mentioned in JEE syllabus - covered separately)
10. Reaction with nitrous acid (specially mentioned in JEE syllabus - covered separately)
11. Reaction with Grignard reagent
Primary and secondary amines react with Grignard reagents to form alkanes.
Tertiary aliphatic amines do not react with Grignard reagent because they do not have hydrogen atom attached to the nitrogen atom.
12. Carbon disulphide
Primary amines react with carbon disulphide to form dithio-alkyl carbamic acids which decompose on heating with mercuric chloride (HgCl2) to give alkyl isothio cyanates. (Hoffman must oil reaction - a test for primary amines).
13. Carbonyl chloride
Primary and secondary aliphatic amines react with carbonyl chloride to form substituted ureas.
14. Ring substitution in aromatic amines
Aromatic amines give the aromatic substitution reactions as given by benzene.
15. coupling of diazonium salts (specially mentioned in JEE syllabus - covered separately)
16. Sandmeyer and related reactions (specially mentioned in JEE syllabus - covered separately)
IIT JEE Revision Basicity of Amines
Chapter Amines
Basicity of substituted anilines and aliphatic amines
Nitrogen has a lone pair in Ammonia are sharing an electron with each of the hydrogen atoms.
Due to the presence of lone pair on nitrogen atom of the -NH2 group, the aliphatic amines are generally basic in nature.
They have a tendency to donate this lone pair of electrons to different electron deficient compounds and, therefore, behave as bases.
The amines react with water to from hydroxides which inonise to furnish hydroxyl (OH-) ions.
The basic strength is expressed in terms of dissociation constant Kb for the dissociation reaction which is a reversible reaction.
Greater the Kb value, which means greater the dissociation at equilibrium, the stronger the base.
Aliphatic amines are stronger bases than ammonia.
It is observed that secondary amines are the strongest bases, next come the primary amines and the weakest among the three are tertiary amines.
The reasons for the strength order of basicity is explained in terms of steric hindrance and solvation of ions.
Aromatic amines are also bases.
Among aniline (NH2 substituted in benzene) and ethylamine, aniline is a weaker base. This is due to the fact tath among the resonating structures of aniline three of them have positive charge on nitrogen. In these cases the lone pair is not available for protonation (for donating the lone pair to the H+ ion). Hence aniline is less basic than ethylamine.
In substituted amines, electron releasing groups like -OCH3, -CH3 increase the basic strength. Electron withdrawing groups like -X (halogen), -NO2, -CN decrease basic strength.
The effects of substituents is more marked at p-position than a m-position.
Every o-substituted aniline (electron releasing or electron withdrawing) is less basic than aniline due to ortho effect.
Base weakening effect of electron withdrawing group is very large at o-position.
When hydrogen atoms of the amino group of arylamines are replaced by electron donating alkyl groups, the basic character of the resulting arylamine increases.
For example, N-methylaniline is a stronger base than aniline and N,N-dimethylaniline is even stronger.
In contrast, if hydrogen atoms of the amino group of arylamines are replaced by electron withdrawing groups (such as phenyl group-aryl group), the basic character of the resulting arylamine increases.
Aniline is stronger than diphenylamines and this is a stronger base than triphenylamine.
In case of aralkylamines where amine group is attached to an alkyl group attached to the carbon of the benzene ring, the lone pair of nitrogen atom is not delocalized and hence readily available for protonation (accepting the H+ ion). Therefore aralkylamines are more basic than arylamines.
Hence benzylamines is a stronger base than aniline.
Basicity of substituted anilines and aliphatic amines
Nitrogen has a lone pair in Ammonia are sharing an electron with each of the hydrogen atoms.
Due to the presence of lone pair on nitrogen atom of the -NH2 group, the aliphatic amines are generally basic in nature.
They have a tendency to donate this lone pair of electrons to different electron deficient compounds and, therefore, behave as bases.
The amines react with water to from hydroxides which inonise to furnish hydroxyl (OH-) ions.
The basic strength is expressed in terms of dissociation constant Kb for the dissociation reaction which is a reversible reaction.
Greater the Kb value, which means greater the dissociation at equilibrium, the stronger the base.
Aliphatic amines are stronger bases than ammonia.
It is observed that secondary amines are the strongest bases, next come the primary amines and the weakest among the three are tertiary amines.
The reasons for the strength order of basicity is explained in terms of steric hindrance and solvation of ions.
Aromatic amines are also bases.
Among aniline (NH2 substituted in benzene) and ethylamine, aniline is a weaker base. This is due to the fact tath among the resonating structures of aniline three of them have positive charge on nitrogen. In these cases the lone pair is not available for protonation (for donating the lone pair to the H+ ion). Hence aniline is less basic than ethylamine.
In substituted amines, electron releasing groups like -OCH3, -CH3 increase the basic strength. Electron withdrawing groups like -X (halogen), -NO2, -CN decrease basic strength.
The effects of substituents is more marked at p-position than a m-position.
Every o-substituted aniline (electron releasing or electron withdrawing) is less basic than aniline due to ortho effect.
Base weakening effect of electron withdrawing group is very large at o-position.
When hydrogen atoms of the amino group of arylamines are replaced by electron donating alkyl groups, the basic character of the resulting arylamine increases.
For example, N-methylaniline is a stronger base than aniline and N,N-dimethylaniline is even stronger.
In contrast, if hydrogen atoms of the amino group of arylamines are replaced by electron withdrawing groups (such as phenyl group-aryl group), the basic character of the resulting arylamine increases.
Aniline is stronger than diphenylamines and this is a stronger base than triphenylamine.
In case of aralkylamines where amine group is attached to an alkyl group attached to the carbon of the benzene ring, the lone pair of nitrogen atom is not delocalized and hence readily available for protonation (accepting the H+ ion). Therefore aralkylamines are more basic than arylamines.
Hence benzylamines is a stronger base than aniline.
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