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CHEMISTRY OF

CARBONYL COMPOUNDS ALDEHYDES ANDKETONES

Teacher: R.Wint

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Objectives

1. Nomenclature of aldehydes and ketones

2. Proerties of aldehyde and ketones

!. "omare the olarity of carbonyl #rous.

$. %&lain the #eneral mechanism of nucleohilic addition in

"'O comounds(. %&lain and illustrate the stes of nucleohilic addition of

hydro#en cyanide to "'O comounds

). *escribe reactions of carbonyl comounds +ith :

Na"N,-"l a

2/$ *NP 0radys Rea#ent3

Tollens Rea#ent

4ehlin#s 5olution

67nO$,-8

-2,Pt

9il-

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"arbonyl "omounds

ldehydes andketones are or#aniccomounds +hich

incororatea carbonylfunc!onal "rou#/"'O.

ldehydes andketones are

resonsible for many

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ldehyde Nomenclature

1. Parent chain must be lon#est chain +ith-"'O #rou.

2. The arent name ends in =al

!. The aldehyde carbon is >1

$. 2 "-O #rous ?$!al%(. @f attached to a rin# the suA&

carbaldehyde is added to the name of therin#

). "ommon names of some aldehydes areaccetable.

e.#.

B&n'&n&carbal$&(y$&)B&n'al$&(y$&*

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Al$&(y$& No+&nclaur&

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Pr&c&$&nc& Or$&r of Func!onal,rou#-

decides +hich #ets to be the arentcomound 0suA&3

9o+er functional #rous must be named as

substituents 0reB&es31. carbo&ylic acid

2. ldehyde

!. 6etone

$. lcohol(. mine

). Thiol

C. hydrocarbon

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K&on& No+&nclaur&

1. 5tes are similar to aldehydes

2. Parent chain is lon#est chain +ith"'O

!. The arent chain ends in on&$. T+o ketone #rous ?dioneD

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6etones and ldehyde in the 5ame

7olecules

s +ith many molecules +ith t+o ormore functional #rous/ one is #ivenriority +hile the other is named as a

substituent.

ldehydes have hi#her riority/ so itis >1/ and the comound takes the

reB& o.o/

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C(&+!cal Pro#&r!&- ofAl$&(y$&- an$ K&on&-

0/ C1O !- #olar $u& o (&&l&cron&"a!2& o.y"&n/

Slightly positive Carbon is attacked by :nu-

3/ Al$&(y$&- +or& r&ac!2& (an 4&on&-

Al$&(y$&- ar& &a-!&r o o.!$!-& (an4&on&-

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P(y-!cal Pro#&r!&- of Al$&(y$&- an$K&on&-

1. oilin# oints increase as themolecules #et bi##er. 5an $&r 6aal Forc&-: These

attractions #et stron#er as themolecules #et lon#er and have moreelectrons.

D!#ol&7D!#ol&8 due to olar "'O/can form ermanent dioles

-i#her .P. than hydrocarbons butlo+er than alcohols of same siEe

because alcohols have (y$ro"&n

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P(y-!cal Pro#&r!&-

1. 5mall aldehydes and ketones arefreely soluble in +ater bu -olub!l!yfall- 9!( c(a!n l&n"(/

4or e&amle/ methanal/ ethanal androanone F the common small

aldehydes and ketones F are miscible+ith +ater in all roortions.

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Nucl&o#(!l!c A$$!!on

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uc &o# cA$$!!on

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Nucleohilic ddition of -"N

asic conditions

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Reactions of aldehydes and ketones:

oxidation

reduction

nucleophilic addition

1) Aldehydes are easily oxidized, ketones are not.

2) Aldehydes are more reactive in nucleophilic additions

than ketones. Due to

a. The presence of that hydrogen atom makes

aldehydes very easy to oxidize

. !etones are more stailised y resonance o"ing to

t"o Alkyl groups

c. !etones have more steric hindrance, #$% is

flanked y t"o caron groups

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alkane alcohol

aldehydeketone

carbo&ylic acid

o&idation

reductionreduction

additionroduct

nucleohilicaddition

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Na"N,-"l0a3

"yanide is classiBed as a moderatenucleohile.

"yanides add to ketones, aldehydes to

form a cyanohydrin 0nitrile3

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O;IDATION REACTIONS

*NP TO99%N5 4%-9@NG/ 67NO$/ "r2OC

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)3-R&a"&n T&-

solution of 2/$ =*NP in methanol and-25O$' Bradys Reagent.

ldehydes and 6etones react +ith thisrea#ent to #ive (& y&llo9 oran"&and r&$ #r&c!#!a&- of 2/$FdinitrohenylhydraEones.

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Toll&n>- )S!l2&r M!rror* T&-

This oxidationreaction is a common test foral$&(y$&-/

Toll&n>- r&a"&n 1 5olution of 5ilver @ Nitrateand ammonia 0#NO!,N-!3.

ldehydes are o&idised to "OO- but 4&on&- ar&no??

This rocess reduces #8to #/ the # t

stickin# to the

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F&(l!n">- Solu!on

4ehlin# solution ' "u 0@@30O-32

in

NaO-.

ldehydes +ill reduce "u28to "u8to a$ar4 r&$ ##/

No reaction +ith ketones/ i.e. 5olution+ill remain blue +ith ketones.

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KMnO=@H

67nO$is a stron# o&idisin# a#ent. Hnder normal conditions only/

aldehydes +ill decolourise 67nO$

6etones are o&idised under e&tremeconditions

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"hromic cid 0"r2OC,-83

"r2OC,-8is not as o+erful as 67nO$.

5imilar outcome as 67nO$

Observation:

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REDUCTION OFALDEHYDES ANDKETONES

-2,Ni/ 9il-/ Na-$

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2) Reduction:

a) To alcohols

&2, 'i

'a(&) or *iAl&)

then &+

C

O

C

OH

H

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2) Reduction:

a) To alcohols

&2, 'i

'a(&) or *iAl&)

then &+

C

O

C

OH

H

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C

O

H

H2, Pt

CH2OH

CH3CHCH=O

CH3 LiAlH4 H+

CH3CHCH2OH

CH3

benzaldehyde benzyl alcohol

isobutyraldehyde isobutyl alcohol