Matriculation Chemistry Amines Part 2

8/12/2019 Matriculation Chemistry Amines Part 2

1/13

Reaction with acyl chlorides

1 and 2 amines are acylated to formN-substituted amides

3 amines are not acylated because they

do not have a H atom attached to N atom.

+

1oamine

R N H

H

Cl C CH3

2 R N C CH3

H

2oamide

+

2oamine

R N H

R

Cl C CH3

2 R N C CH3

R

3oamide

+ HCl

+ HCl


2/13

Reaction with acid anhydride

1 and 2 amines are acylated to form

N-substituted amides

3 amines are not acylated because they

do not have a H atom attached to N atom.

R N C CH3

H

2oamide

+

1o

amine

R N H

H

CH3 C C CH3

acid anhydride

+ CH3CH

+

2oamine

R N H

R

CH3 C C CH 3

acid anhydride

R N C CH3

R

3oamide

+ CH3CH


3/13

Reaction with ben!enesul"honyl chloride

Hinsber#$s test

%his reaction is used to differentiate

between 1& 2and 3 amines.


4/13

'en!enesul"honyl chloride reacts with a1 amine to form a white "reci"itate

(N-substituted sul"honamides)

11 amineaminess

(-HCl)

Acidic hydrogen

NaOHN-substituted sul"honamides have an

acidic hydro#en& N-H.

%herefore& it dissolve in a*ueous NaH.

R-N-H

H

+

Cl-S-

O

O

OH-

1 amineo

O

O

-S-R-N

H

(precipitate)

N-substituted

benzenesulphonamides

O

O

-S-R-N

Na

water soluble salt

(clear solution)

Acidic hydrogen


5/13

N,N-disubstituted sul"honamides do not

have an acidic hydro#en& N-H.

22 amineaminess

(-HCl)

%herefore& it dissolve in a*ueous NaH.

'en!enesul"honyl chloride reacts with a

2 amines to form a white "reci"itate

(N,N-disubstituted sul"honamide)

NaOHNo reaction

Cha"ter 1 , mines

1.3 , hysical ro"erties 1./ , re"aration 1.0 , Chemical "ro"erties

1.1 , ntroduction 1.2 , Nomenclature

1.0

Reaction with ,Reaction with ,

cyl chloride

cyl chloride

cid anhydridecid anh

ydride

'en!enesul"honyl'en!enesul

"honyl

chloridechloride

Nitrous acidNitrous acid

'romine water'romine water

ormation of dye

R-N-H

R'

+ Cl-S-

O

O

OH-

2 amineo

O

O

-S-R-N

R'

(precipitate)

NN-disubstitutedbenzenesulphonamides


6/13

33 amineaminess

3 amine do not #ives visible reactionwith ben!enesul"honyl chloride

1 amineswhite "reci"itate clear

solution

NaH

ummary of Hinsber#$s test,

2 amines

white "reci"itate

do notdissolved

NaH

3 aminesdo not #ive any visible

chan#e


7/13

Reaction with nitrous acid (NaN2+ HCl)

Nitrous acid (HN2) is a wea4 and unstableacid.

t is always "re"ared in situ& by treatin#

cold sodium nitrite (NaN2)with an

a*ueous solution of a cold dilutehydrochloride acid (-0C).

Nitrous acid reacts with all classes of

amines

Nitrous acid test can be used to distin#uish,51 ali"hatic and 1 aromatic amines51 and 2 ali"hatic amines


8/13

rimary ali"hatic amines react with

nitrous acidto yield hi#hly unstable

aliphatic diaonium salts

11 amineamines (Aliphatic)s (Aliphatic)

C!C + ROH + R"bservation ,

ormation of #as bubbles

(N2)

R-N-H

H

1 amineo

NaNO2 H"

-# to $ Co% R-N N" &

+

aliphaticdiazonium salt

(unstable)

-N2R

++

"

-

carbocation


9/13

rimary arylamines react with nitrousacidto #ive arenediaonium salts

11 amineamines (Aromatic)s (Aromatic)

NH2N2

+Cl

+NaN2& HCl

cold

NaCl H2+

arenediazonium salt


10/13

rimaryali"haticamines

orm a mi6ture of al!enes&alcohols& al!yl halidesandnitro#en #as.

econdary

ali"haticamines

orm secondary "-

nitrosaminesas yello# oil&whichis stable under thereaction conditions.

1 ali"hatic amines and 2 ali"hatic amines


11/13

Reaction with bromine water

niline reacts with a$ueous bromineto

yield #hite precipitates

"H2#rou" is an acti%atingand ortho-

para directors group

+

NH2 NH2

'r

'r

'r3'r2(a*)

room tem"erature 3H'r

(2&/&7-tribromoaniline)

bservation, 8hite "reci"itate formed

dentificationtest


12/13

ormation of dye

rimary arylamines react with nitrous acidto #ive arenedia!onium salts which are

stable at & C

renedia!onium salts also under#o coupling

reactionwith aromatic com"ounds with

stron# electron donatin# #rou"& such as 9H

and 9NR2at thepara"osition to yield a!o

com"ounds

!o com"oundsare usually intensely

colouredand relatively ine6"ensive

com"ounds& they are used as dyes


13/13

N N ":

-+

OH

N!N

N

(orane)

OH

CH

CH

N!N

(ellow)

NCH

CH

Documents

Matriculation Chemistry Amines Part 2