Amine
source: science aid.co.uk
Amine
Amines are derivatives of NH3 formed by the replacement of hydrogen atoms by alkyl groups.
Primary amine : RNH2 Ex. CH3NH2 , CH3CH2NH2
Secondary amine : R2NH Ex. (CH3)2NH , CH3CH2NHCH3
Tertiary amine : R3N Ex. ( CH3)3N , (CH3CH2)3N
ETHYL AMINE [ CH3CH2NH2 ]
IUPAC name- Ethanamine
Methods of preparation-
1- By the reduction of nitroethane—- When reduced by Sn/conc. HCl, LiAlH4/ether then we get ethanamine .
C2H5NO2 +6[H]————–>C2H5NH2 +2H2O
2- By the reduction of Methyl cyanide—-When reduced by Na/C2H5OH , Zn/H2SO4, LiAlH4/ether then ethanamine is formed.
CH3CN +4[H]————–>CH3CH2NH2
3- By the reduction of Acetamide— When reduced by Na/C2H5OH , H2/Ni , LiAlH4/ether then ethanamine is formed.
CH3CONH2 +4[H]————–>CH3CH2NH2 +H2O
4— By Schmidt reaction— When propionic acid reacts with hydrazoic acid in presence of conc. H2SO4 then we get ethanamine.
C2H5COOH +N3H——->C2H5NH2 +N2 +CO2
5– From Grignard reagent— When ethyl magnesium bromide reacts with chloramine then we get ethanamine .
C2H5MgBr +ClNH2——->C2H5NH2 + Mg(Br)Cl
6— By the hydrolysis of ethyl isocyanate—-On hydrolysis with KOH gives ethanamine.
C2H5NCO +2 KOH——–> C2H5NH2 +K2CO3
7—- By Hofmann’s method or From etyhl halide—- When aq. or alc. NH3 & ethyl halide are heated in a sealed tube at 100 degree C , a mixture of primary , secondary , tertiary amine & quaternary ammonium salt is formed.
C2H5Br +NH3——->C2H5NH2 +HBr
C2H5NH2 + C2H5Br—–> ( C2H5)2NH + HBr
(C2H5 )2NH + C2H5Br ——->( C2H5)3N + HBr
( C2H5)3N + C2H5Br —–> [( C2H5)4N] +Br- [Tetra ethyl ammonium bromide or Quaternary ammonium salt]
9– From Ethyl alcohol–
When NH3 & vapours of ethyl alcohol are passed over heated Al2O3 at 360 degree C , a mixture of primary , secondary & tertiary amine is formed.
C2H5OH +NH3——->C2H5NH2 +H2O
C2H5NH2 + C2H5OH—–> ( C2H5)2NH + H2O
(C2H5 )2NH + C2H5OH ——->( C2H5)3N + H2O
10— By Hofmann Bromide reaction — When propanamide is heated with Br2 & alc. KOH then we get ethanamine .
C2H5CONH2 + Br2—->C2H5CONHBr +HBr
HBr + KOH ——>KBr +H2O
C2H5CONHBr +KOH ——> C2H5NCO +KBr +H2O
C2H5NCO + 2KOH—–> C2H5NH2 +K2CO3
As a whole HOFMANN BROMIDE REACTION is,
C2H5CONH2 +Br2 +4KOH—->C2H5NH2 +K2CO3 +2KBr +2H2O
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