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CLASS-12th

N

BEST HANDWRITTEN NOTES

MADE

WITH

By-Bharat

Panchal Sir

bharatpanchal 92

Chemistry Bj^

use n p

demistryj m

AMINES

Those organic compounds formed^ by replacing one^ or^ more^ hydrogen

of ammonia molecule

by alkyl and^ anyl group.

STRUCTURE OF^ AMMONIA^ : Nitrogen atom^ in^ amines^ is^ trivalent^ i

. (^) e it (^) forms D three covalent bond.The (^) nitrogen alom also (^) has one (^) love (^) pair of electrons. 'N' atom in (^) all amines is (^) sp 1 yosn^ hybridised which^ has^ tetrahedral (^) geometry but their shape is^ pyramidal PASSIFICATION al (^) primary amines^ If (^) one (^) hydrogen alom of ammonia is^ replaced (^) by (^) alky, or anyl group^ R-NH Or^ Foy-NH b) (^) Secondary Amines If two (^) hydrogen alom of ammonia is^ replaced by alkyl or^ any group. R-NH-R (^) orYNH-TY c) (^) Tertiary Amines^ : If three^ hydrogen alom^ of ammonia^ is^ replaced (^) by alkyl or^ anyl group. R-NR orNEX a T NOMENCLATURE : for 10 amine =^ - NH,

for 2 amine^ =^ -NK-

for 30 amine^ =-N suffix (^) used = (^) -Amine Prefix used =^ Amino CH CHy-CH2-NH2 CHy-CH-CH] (^) CHy-N-CH] Ethanamine Nnz^ N,N-Dimethy methanamine Propan-2-amine Hy CHy-(Har(Hy-N-CK2-Chy Ex-NH N-Ethyl-N-methyl propan-2-amine^ Aniline

norfman Ammonolysis^

valoalkanes on heating with^ ammonia^ give a^ mixture

of (^10) , (^20) ,^30 amines^ and^ quaternary ammonium^ salt. RX + (^) NHy (^) R-NU +RX RINtR-X-^ >

• UX PyNtR-X-^ RANTY 10 amine (^) 2'amine 30 amine guaternary ammonium salt (45-Bu +^ Nycall) < (^) CHS-N +^ CH5 -Br^ < (^) KustNU + (^) GH5 Br [5-J5B

• , NOTE :^ This method (^) can not be used to^ prepare anylamines because (^) any halides (^) are much less reactive towards (^) nucleophilic substitution reactions than (^) alkyl halides.The (^) reactivity order of^ alkyl halide is^ RIYR-BUY R- 1 HOFFMANN'S BROMAMIDE (^) DEGRAdation By this^ method,^10 amines^ are^ prep-

• ared from acid amides with (^) one carbon less than (^) parent acid amide. Acid amide on treatment with^ Bre and (^) aqueous or alcoholic^ alkali^ (Non or Kou) (^) gives 10 amine Ng + (^) Br +On (^) ^ CHNc +^ 2KBU + KCO> +^240

#CONC +^ Br +Non^ > EN +^ &NaBu +^ NacCOy +^ Eng GABRIEL PUTHALIMIDE SYNTHESIS^ : When (^) puthalimide is^ treated with^ alcoholic solution of (^) potassium (^) hydroxide, potassium salt of^ phthalimide is^ formed

which on

heating with alkyl halide followed (^) by alkaline (^) hydrolysis produces a^ primary amines N KON, ON R-X ,R Non , (^) RNA egN^ KonON^ CH5-

, YOTN-CUS-IN

15-WUOM

PHYSICAL PROPERTIES PHYSICAL STATE AND SMELL The (^) lower (^) aliphatic amines^ are (^) gases with^ fishy odour. Primary amines^ with^ three or more carbon atoms are (^) liquid and still (^) higher ones are solid. Among arylamines^

the lower^ members^ are

liquid while^ higher members^ are^ solid. BOLLING POINTS : Amines can form intermolecular^ hydrogen (^) bouding. So (^) they have (^) higher bpt than (^) alkanes of^ comparable molecular (^) mass. · Among isomeric amines^ , 10 amines have (^) higher bpt than 20 amines and 20 amines have higher boiing point^ than^30

amines .

Chy(CH), NH2 Y^ (Hy-CH2-NH-CHs Y^ CHy-N-CH > decreasing order^ of^ boiling point This is^ because 10 amines have two (^) hydrogen atoms in^ amino^ group. So these have (^) more (^) hydrogen (^) bonding whereas 20 amines^ has (^) only one (^) hydrogen atom and^30 amine^ has^ no^ hydrgen : cas-on ... Cn3 (^) CHs

CHy-N-1 ..... CHy-N-CH]

carboxylic acids^ and^ alcohols^ have^ higher^ boiling point^ than^ amines^ because carboxylic acids^ and^ alcohols^ are^ more^ polar^ than^ amines So, they have (^) stronger hydrogen (^) bouding and have higher (^) boiling points.^ HCOOK (^) > (^) Chy(HOn > (^) ChyCHNNg Y (^) CHyCHaCHy solubility : Lower (^) aliphatic amines^ are soluble^ in^ water due to^ formation^ of intermolecular (^) hydrogen bouding with (^) water (^) molecules .

• • hydrogen Bond As the size^ of^ alkyl group increases^ ,the^ hydrophobic character^ also increases. So (^) , tendency to (^) form (^) hydrogen bond decreases and (^) solubility also decreases. That is (^) why amines with six^ or more carbons (^) are insoluble in (^) water. All aromatic amines^ like quiline and^ toluidine (^) are insoluble in water but^ are soluble in^ organic solvents.

3 amine^ < 20 amine^ /20 amine Y increasing order^ of^ basic^ strength SOLYATION OF IONS

It means the energy released due to attraction of water

molecules with^ positive ammonia ion^ of^ amines^ Larger the^ hydrogen bonding is (^) , more is (^) solvation and more is (^) stability of cation. So (^) more is (^) basic strength Rining +so--renas^ +^ one (^1) amine Ammonium^ ion Nork : H This^ ammonium^ ion^ forms^ hydrogen^ bonding

REN-n----o

from three sides. So^ , more^ energy is^ released

and more is^ the^ stability

n

Re-in +^10 -- Ratin, +^ one 2 amine Ammonium^ ion 4 - 0 - 4 his ammonium^ ion^ forms (^) hydrogen (^) bonding i (^) from (^) two sides. So , less^ energy in^ released

• than 10 amine^ and^ less^ is^ its^ stability.

Rs- +^40 ~^ Ryan +^ one

3 amine Ammonium ion

R Runn ... oThis^ amomumonforms hydrogen bondingn^ aa and (^) its (^) stability is^ also the least. eg Basic^ strength^ of^ ethylamine^ (^3) Basic (^) strength of (^) methyl amine 2073019 20710739 (Cust, in y^ (GUst,NY^ CH5NUc (Cn])2Nn >^ crynx (Ch]), N · (^) In aromatic amines, steric hindrance and (^) resonance factors are more (^) domina-

• ting factors (^) whereas in^ avalkyl amines t (^) effect dominates. Rin>in <

NOTE : · electron withdrawing group like-coon,^ -coll^ ,^ -Conc , -OR^ ,

• CN , -SOgH^ ,^ -NO^ , -X^ ,^ decrease^ the^ electron^ density^ on^ nitrogen of^ aniline Hence decrease^ the basic^ strength of^ amines.

· electron

donating groups^ like-Chy-Ocks^ ,^ -on , -NH^ etc^ increase^ the electron (^) density on (^) nitrogen hence^ increase^ the basic (^) strength of^ amines^.

· Outho effect includes steric hindrance as well as some electronic factors .

NH ↓

Ning dens^ 'NO · ↓ f^1 E.^ D.^3 increase the basic (^) strength E-^ W. G decrease the basic of aniline (^) strength of aniline larger the^ number^ of^ electron^ releasing alkyl group is, more^ is^ the^ basic CHI (^) strength YN -n Y (^) xnn-c >NAC E.^ W. G like (^) phenyl (^) group , the basic (^) strength of (^) anyl amine decreases. #N (^) Ey ^ Chy^ NGe

⑦ TXNUC +^ UC^ >^ KNH> C Ch

• in^ +^4504 - no -methyl anilinium hydrogen sulphate

ACYLATION :^ Ryn with^ acid chloride or acid anhydride

gives substituted CHy-NHc +^

• • My Chy--c^ +^40 acid amides

#Nuc +^ -0.-cy^ EN-- my^ +^ n

SECONDARY AMINES o (^) Cl as kon (^) , No (^) Change it (45-NC-S

• G

insoluble in alkali

TERTIARY AMINES

'gU5-NHs

+ U-SO- >^ No^ Reaction^

do (^) not have (^) any (^) are replacable (^) hydrogen , Electrophilic substitutionReaction-Ne is (^) highly activating group^

. So, aniline is^ more reactive (^) than benzene

ring

RESONANCE IN^ ANLINE^ : ⑦ NM2 iNH

It is o- and

p-directing Bromination : In the absence of^ catalyst (^) ,^ aniline^ on treatment^ with^ bromine^ water at room^ temperature form a while^ ppt of^2 , (^4) , 6-tribomo^ aniline N +^ 3 BV "O , BrN

• (^) 34BU This reaction (^) can be used to (^) distinguish aliphatic and aromatic 10 amines.

Protection of amino group :

Due to activation^ of benzene ring ,^ a trisubstituted product is^ formed.^ So^ aniline^ is^ protected^ by acylation to^ get mono^ substituted product.^ Mn

• Cs-0-- (^) nt^ chycoon : : e

n - N -^ C^ - CH

To

Y (^) Y n s- On (^) aculation (^) , acctanilide is^ formed in^ which^ -group is^ electron withdra

wing group^.

The (^) love (^) pair of te (^) on (^) nitrogen atom is less available for donation to (^) benzene ring by^ resonance.^ So^ , activating effect of^ -NucoCs group is (^) less than that (^) of -NH

, group^.

(^) NITRATION :

Before (^) protection, quiline (^) gives a mixture (^) of o (^) , p and m-isomer NH2 NU

• Conc^ UNO (^) conenaseo two Nas (52 %) (47 %^ ) ( %)

Due to^ protonation , quilinium^ ion^ is^ formed^ which^ is^ E^.^ W.^ G.^ So^ this^ decrease

the electron^ density at^ o and^ p-positions and (^) electrophile nitronium ion

CIO) also^ attacks^ at^ meta^ position^.

⑦NH

• -Fo NU ⑦

NHL

U M &Resonance in (^) anilinium ion 1 After (^) protection, only outho^ and^ para isomers^ are^ formed NHS (^) (CH3(0)20 Nitration To (^) Acylation >oucos o couc. UNOs + ConciseOc WhenT I No

• bot Ne sulphonation Aniline is^ basic^ in^ nature.^ So, firstly it^ forms^ salt^ with^ conc So+ which on healing up to 453-473K^ gives p-isomer in (^) sulphanilic acid as a (^) major product.^ ① NH conc No ~ No, whysof Anilinium hydrogen sulphate^ sulphanilic acid.
• (^) sulphanilic acid (^) is (^) used as the starting material^

for the

manufacturing

of antibiotics^ called^ sulphadrugs. ZWITTERION :^ It is^ a (^) dipolar ion which^ is^ formed^ due^ to^ internal^ salt formation between basic^ group (NU) and acidic (^) group(-SO,H).

GATTERMANN'S REACTION

Nall C

Bu Powders +N + NaCl I (^) Cy Noy +^ ne (^) Powder N

+ C

· BALZ-SCHIEMANN REACTION

NIC- F nife (^) , +^ N^

• (^) B

Benzene diazonium

fluoroborate · (^) replacement by 10 ion Nice-

[]

• (^) He Nati · Replacement by Cyano^ group^ (Sandmeyer's^ Reaction) Nich

1 +^

N (^) + N2tGN · Replacement by H^ Benze is (^) formed. Mild

reducing agent

like (^) phosphinic acid CHPOG) or^ ethanol^ reduce^ diazonium^ salt (^) to benzene Natc-

By Hypoc^ +Ho fo NathypOy

+C

Phosphorous

Acid No- To]

• (^) Mycnon + Ne+^ CHICHO^
• (^) He Acetaldehyde replacement by^ Hydroxyl Group : N^20 +N +^ n Phend. Replacement (^) by -No, (^) group : Not -^ Not^ BF

] Indra^ 1 NaNO , C Na +^ NaBE

(^) COUPLING REACTION :

Benzene diazonium^ chloride^ couples with to^ rich aromatic compound like^ pheno^ and^ aniline^ at^ their^ para positions^ and^ give ato

dyes

EN +^ -YonOne o >^ [N2-tyon

Phenol (^) p-Hydroxy a zobenzene corange dye) [Y-Np

n-1YNH n + > (^) ENu-YYNA Aniline p-Amino azobenzene Cyellow (^) dye) Dye test, this^ reaction^ is^ used^ to^ distinguish Aliphatic and^ Aromatic^ amines