Amines Flashcards
Drawback of ammonolysis of alkyl halides
A mixture of compds are obtained
What will be formed when OH is used instead of H for hydrolysis in gabriel phthalimide synthesis?
The compound’s salt will be formed
Why can’t aromatic amines be formed by Gabriel reaction?
Due to difficulty of aryl group to react due to partial double bond, instability of phenyl cation, sp³ attached to sp² and presence of e’ rich benzene
Why is Fe/HCl preferred over Sn/HCl for reduction of nitro group?
Since HCl is produced as 1 of the products which can later be used by Fe again to give H+ used for reduction
Why can’t LiAlH4 be used with aliphatic compds?
It will not give amines
Why are aliphatic amines more basic than aromatic?
Since lone pair in aromatic is used for resonance
For acylation of amines, which doesn’t react?
3° amine since it doesn’t have H on it.
Hinsberg reagent
Benzene sulphonyl chloride
Hisnberg reagent will not react with?
3° amine since it doesn’t have H
Test to distinguish amines
Hinsberg reagent test which is not given by 3° amine
3methyl aniline to 3 nitrotoluene
Diazotization + NaNO2(Cu, heat)
aniline + benzoyl chloride
N phenyl benzamide
aniline to 1,3,5-tribromobenzene
Br2/H2O + Diazotization + Cu(H3PO3 + H2O)
distinguish ethylamine & aniline
azo dye test(HNO2 + HCl) + dil.NaOH
Distinguish Aniline & benzylamine
HNO2 + H2O
Why is pKb of aniline more than that of methyl amine?
E` pair is involved in conjugation so it is less available for protonation than methylamine
Why Ethylamine is soluble in water but aniline is not?
H bonding but in aniline, due to bulky part, bonding is less
Methyl amine in water reacts with FeCl3 to ppt rust
Methylamine is more basic than water so it accepts a proton from water
Why although amino group is o- & p- directing in aromatic electrophilic substitution, aniline on nitration also gives m-nitroaniline?
aniline gets protonated in the presence of conc. HNO3 & conc H2SO4 to form anilium ion which is m- directing
Aniline doesn’t undergo Friedel Crafts reaction. Why?
Aniline begin a lewis base forms a complex with AlCl3, a lewis acid. So N of aniline becomes +ve & acts a strong deactivating group
Diazonium salts of aromatic amines are more stable than those of aliphatic amines. Why?
Aromatic amines are resonance stabilised unlike in aliphatic amines.
Gabriel phthalimide synthesis is preferred for synthesising primary amines. Why?
It produces primary amines only without traces of secondary or tertiary amines.
ethanoic acid to methanamime
SOCl2 + NH3 + Hoffmann
hexanenitrile to aminopentane
H3O(partial) + Hoffmann
