a2 chemistry carboxylic acids and their derivatives

7/23/2019 A2 Chemistry Carboxylic Acids and Their Derivatives

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New Way Chemistry for Hong Kong A-Level Book 3B1

A2 chemistryCarboxylic Acids

and their Derivatives35.135.1 ntro!"#tionntro!"#tion

35.$35.$ Nomen#lat"re of Car%o&yli# A#i!s an! their Nomen#lat"re of Car%o&yli# A#i!s an! their'erivatives'erivatives

35.335.3 (hysi#al (ro)erties of Car%o&yli# A#i!s(hysi#al (ro)erties of Car%o&yli# A#i!s

35.*35.* (re)aration of Car%o&yli# A#i!s(re)aration of Car%o&yli# A#i!s35.535.5 +ea#tions of Car%o&yli# A#i!s+ea#tions of Car%o&yli# A#i!s

35.,35., +ea#tions of the 'erivatives of Car%o&yli# A#i!s+ea#tions of the 'erivatives of Car%o&yli# A#i!s

35.35. ses of Car%o&yli# A#i!s an! their 'eri vati vesses of Car%o&yli# A#i!s an! their 'eri vativ es



New Way Chemistry for Hong Kong A-Level Book 3B$

/eneral form"la of #ar%o&yli# a#i!0 RCOOH

Examples:

AS recap




Name StructureA#yl#hlori!es

A#i!anhy!ri!es

Ami!es

sters

Carboxylic acid derivatives



New Way Chemistry for Hong Kong A-Level Book 3B*

Nomenclature of Carboxylic Acids and their Derivatives

Car%o&yli# a#i!s are name! %y replacing the final “-e” ofthe name of the corresponding alkane with “-oic acid”

When other s"%stit"ents are )resent2 the carbox l carbon isassigned position !

Examples:

Carboxylic Acids

Carboxylic Acids




A#yl #hlori!es are name! %y replacing the final “-ic acid”of the name of the parent carbox lic acid with “- l

chloride”

Examples:

Acyl Chlorides

Acyl Chlorides




New Way Chemistry for Hong Kong A-Level Book 3B,

A#i! anhy!ri!es are name! %y dropping the word “acid”from the name of the parent carbox lic acid an! thenadding the word “anh dride”

Examples:

Acid Anhydrides

Acid Anhydrides




New Way Chemistry for Hong Kong A-Level Book 3B

Ami!es that have no s"%stit"ents on the nitrogen atom are name!

%yreplacing “-oic acid” from the parent carbox lic acid with“amide”

4"%stit"ents on the nitrogen atom of ami!es are name! an! thename! s"%stit"ent is )re#e!e! %y N -" or N " N -

Examples:

Amides Amides





6he names of esters are !erive! from the names of the

al#ohol 7with the en!ing “- l” 8 an! the #ar%o&yli# a#i! 7withthe en!ing “-oate” 8

6he )ortion of the name !erive! from the al#ohol #omes first

Examples:

Esters Esters





Tutorial Question 1Tutorial Question 1#i$e the %&'(C names of the following compounds)

*a+

*b+

*c+

*d+

Answer

Solution:

(a) 3-Methylbutanoic acid

(b) N -methylethanamide

(c) Ethyl benzoate

(d) Benzoic anhydride




New Way Chemistry for Hong Kong A-Level Book 3B1:

Tutorial Question 2Tutorial Question 2(n ester is formed b reacting an alcohol with a carbox licacid, raw the structural formula of the following estermolecule and gi$e the name of the alcohol and thecarbox lic acid that form the ester,

*a+ .eth l ethanoateAnswer Solution:

(a) The structural formula of methyl ethanoate is

!t is formed from the reaction of ethanoic acid andmethanol"





Example !"2Exam ple !"2(n ester is formed b reacting an alcohol with acarbox lic acid, raw the structural formula of thefollowing ester molecule and gi$e the name of the alcoholand the carbox lic acid that form the ester,

*b+ /th l methanoateAnswer

Solution:

(b) The structural formula of ethyl methanoate is

!t is formed from the reaction of methanoic acidand ethanol"




New Way Chemistry for Hong Kong A-Level Book 3B1$

Chec# $oint !"1Chec# $oint !"1Complete the following table b filling in the molecularformulae" structural formulae or %&'(C names of thecarbox lic acids,

Answer

;ole#"lar form"la 4tr"#t"ral form"la (AC name

C3H C<<H 7a8 7%8

7#8 7!8

7e8 7f8

7g8 7h8 6ri#hloroethanoi# a#i!

7a8

7%8 B"tanoi# a#i! 7#8 CH3CH7CH

38CH

$C<<H

7!8 3-;ethyl%"tanoi# a#i!

7e8 C, H*ClC<<H 7f8 $-Chloro%en=oi# a#i!

7g8 CCl3C<<H

7h8





!0 and 10 alk l groups 7%"t not 3>8directl attached to aben2ene ring are o&i!i=e! %y hot K;n< *?<H @ to #ar%o&yl gro")e.g.

Oxidation of AlkybenzenesOxidation of Alkybenzenes

!%& #re$aration of Carboxylic Acids %&B $"3'(

6his o&i!ation takes )la#e initially at the ben2 lic carbon alkyl gro")s longer than methyl gro") are "ltimately

!egra!e! to %en=oi# a#i!



New Way Chemistry for Hong Kong A-Level Book 3B1*

6he a#i! strength of ethanoi# a#i! is shown %y the val"e of its

acid dissociation constant *3 a+

C<<HCH<HC<<CH

K 3

33a

+

=

-

p3 a is "se! for #onvenien#e as K

a is small for weak a#i!s

p3 a 4 5log 3 a 2the smaller the p3 a $alue" the stronger is the acid

p3 a is "se! for #onvenien#e as K a is small for weak a#i!s

3 a 4 !6-p3a

smaller the p3 a $alue" the stronger is the acid

ethanoic acid




Car%o&yli# a#i!s are stronger a#i!s than

al#ohol %e#a"se(oint 1a86he #ar%onyl gro") weakens the <-H %on! ..thismeans

6he very ele#tronegative o&ygen in Car%onyl gro") has anele#tron with!rawing effe#t an! )olari=es the <-H %on!.(oint $

%8 #ar%o&ylate ion is sta%ili=e! %y the !elo#ali=ation ofele#tron aro"n! the #ar%o&ylate ion this means6he negative #harge is s)rea! o"t in the #ar%o&ylate ionan! is less likely to attra#t the hy!rogen ion.



New Way Chemistry for Hong Kong A-Level Book 3B1,

6he greater sta%ility of #ar%o&yli# a#i!s is attri%"te! toresonance stabili2ation of the carbox late ions

&am)le0

Resonance Effect




p3 a is "se! for #onvenien#e as K a is small for weak a#i!s

p3 a 4 5log 3 a 2the smaller the p3 a $alue" the stronger is the acidp3 a is "se! for #onvenien#e as K a is small for weak a#i!s

3 a 4 !6 -p3a

7he smaller the p3 a and larger the 3 a$alue" the stronger is the

acid




p3 a increases and acid becomes weaker when no of C

and H atoms in molecule increases,

(lk l groups are electron donating groups that makes

the O-H bond stronger and less h drogen ions are

released from carbox lic acid,

Name 8ormula p3 a

;ethanoi# a#i!

thanoi# a#i!

(ro)anoi# a#i!

B"tanoi# a#i!

Ben=oi# a#i!

HC<<H

CH 3C<<HCH 3CH $C<<H

CH 3CH $CH $C<<H

C , H5C<<H

3. 5

*. ,

*.

*. $

*.$:

ns"%stit"te! #ar%o&yli# a#i!




By the resonan#e effe#t2 the ethanoate ion #an %esta%ili=e! %y spreading the negati$e charge o$er two

ox gen atoms

!%! )eactions of Carboxylic Acids %&B $"*+(

No stabili2ing resonance structures for alkoxide ions e.g.

Carbox lic acids are much acidic than alcohols formation of more stable con9ugate base

f $



New Way Chemistry for Hong Kong A-Level Book 3B$:

Both #om)o"n!s #ontain the highl polari2ed O 5 Hbond !"e to the difference in electronegati$it

6he greater acidit of ethanoic acid is !"e to the )resen#e of the )owerf"l electron-withdrawing carbon lgroup


Inductive Effect

% ) i f C b li A id %& $ (



New Way Chemistry for Hong Kong A-Level Book 3B$1

6he carbon l atom of ethanoi# a#i! %ears a large

partial positi$e charge an! e&erts a powerful electron-withdrawing inducti$e effect to hy!ro&yl o&ygen atom2making the h drox l h drogen atom much morepositi$e

proton dissociate more readil

6he electron-withdrawing inducti$e effect of thecarbon l group stabili2es the carbox late ion

carbox lic acids are stronger acid than alcoho ls


6wo resonance structures for the #ar%onyl gro")0

!%! ) i f C b li A id %&B $"* (



New Way Chemistry for Hong Kong A-Level Book 3B$$

1. Electron-withdrawin !ro"ps

7he presence of electron-withdrawing groups increasethe acidit of a carbox lic acide.g.

!%! )eactions of Carboxylic Acids %&B $"*,(

Inductive Efects o OtherGroups

!%! ) i f C b li A id %&B $"* (




6he chlorine atom with!raws ele#tron from the #ar%onyl

gro") an! o&ygen making the h drox l h drogen morepositi$e than that of ethanoi# a#i!

!%! )eactions of Carboxylic Acids %&B $"*,(

6he #hlorine atom also stabili2es the #hloroethanoate ionto greater e&tent

!%! ) ti f C b li A id %&B $"*+(



New Way Chemistry for Hong Kong A-Level Book 3B$*


CH 3C<<H D D D D

thanoi# o!oethanoi# Bromoethanoi# Chloroethanoi#El"oroethanoi#

a#i! a#i! a#i! a#i! a#i!*. , 3.1 $.9: $. , $.,,

A#i!ity

)K a

CH 3C<<H D D D CCl 3C<<H

thanoi# Chloroethanoi# 'i#hloroethanoi# 6ri#hloroethanoi#a#i! a#i! a#i! a#i!*. , $. , 1.$9 :.,5

A#i!ity

)K a

Effect of electron-withdrawing substituents on the acidity of carboxylic acids

7he greater the number of electron-withdrawing groups" thestronger is the acid

7he more electronegati$e of halogen substituents *8 : Cl :

;r : %+" the stronger is the acid

!%! ) ti f C b li A id %&B $"*3(




!%! )eactions of Carboxylic Acids %&B $"*3(

6he f"rther away of the s"%stit"ents from the #ar%o&yl

gro")2 the weaker is the a#i!

D D

*-Chloro%"tanoi# 3-Chloro%"tanoi# $-Chloro%"tanoi#a#i! a#i! a#i!*.5$ *.:, $. *

A#i!ity

)K a

!%! ) ti f C b li A id %&B $"*3(



New Way Chemistry for Hong Kong A-Level Book 3B$,

#. Electron-releasin !ro"ps

7he presence of electron-releasing groups reduce theacidit of a carbox lic acide.g.







le#tron-releasing alkyl gro")s release electrons towar!s theelectron-deficient carbon l carbon 2 th"s re!"#ing its #harge

Reduce the positi$e character of the h drox lh drogen atom

dissociate less readil

%ntensif the negati$e charge on the #ar%o&yl gro") destabli2es the ethanoate ion

!%! )eactions of Carboxylic Acids %&B $"**(




Chec# $oint !"Chec# $oint !"

*a+ .atch the 3 a $alues) 1,!< !6 5=

. and !,1> !6 5=

."to the carbox lic acids) CH 18COOH and

CH 1;rCOOH, /xplain our answer briefl ,

Answer

!%! )eactions of Carboxylic Acids %&B $ **(

7a8 6he greater the K a val"e2 the stronger is the a#i!.

CH $EC<<H is a stronger a#i! than CH $BrC<<H.6his @E s"%stit"ent e&erts a stronger in!"#tive effe#tthan the @Br s"%stit"ent2 as fl"orine is moreele#tronegative than %romine. 6he @E s"%stit"entsta%ili=es the #onF"gate %ase 7i.e. CH $EC<<H @ 8 to a

greater e&tent than the @Br s"%stit"ent. 6herefore2CH $EC<<H has a K a val"e of $.19 × 1: @3 ;2 an!CH $BrC<<H has a K a val"e of 1.$, × 1: @3 ;.






*b+ (rrange the following acids in ascending order of acidit )CHCl 1COOH" CCl =COOH" CH 1ClCOOH" CH =COOH

/xplain the order briefl ,Answer


7%8 CH3C<<H D CH $ClC<<H D CHCl $C<<HD CCl3C<<H

6he @Cl s"%stit"ent is an ele#tron-with!rawinggro"). An in#reasing n"m%er of the @Cl s"%stit"ent

%rings a%o"t a greater negative in!"#tive effe#t.6h"s2 the #onF"gate %ase will %e sta%ili=e! more2an! the a#i!ity of the a#i! in#reases.






*c+ (rrange the following ar l carbox lic acids in descendingorder of acidit )

/xplain the order briefl ,







7#8

is more a#i!i# than 2%e#a"se #ontains

the @Cl s"%stit"ent whi#h is an ele#tron-with!rawing gro"). 6h"s2 ite&erts a negative in!"#tive effe#t to the #onF"gate %ase2 an! hen#e

sta%ili=es the #ar%o&ylate ion forme!.

is less a#i!i# than 2 %e#a"se #ontains

a methyl gro") whi#h is an ele#tron-releasing gro"). 6h"s2 it e&erts a )ositive in!"#tive effe#t to the #onF"gate %ase2 an! hen#e !esta%ili=esthe #ar%o&ylate ion forme!.






*d+ ?hich is a stronger acid" CH 1ClCOOH orCH =CHClCOOH@ /xplain our answer briefl ,

Answer

!%! )eactions of Carboxylic Acids %&B $ (

7!8 CH$ClC<<H is a stronger a#i! as CH 3CHClC<<H#ontains a methyl gro") whi#h is an ele#tron-releasinggro"). t e&hi%its a )ositive in!"#tive effe#t an! th"s!esta%ili=es the #onF"gate %ase of the a#i!. 6herefore2CH 3CHClC<<H is less a#i!i#.





Car%o&yli# a#i!s rea#t with reacti$e metals s"#h as Naor ;g to give the #orres)on!ing metal carbox lates an!h drogen gas

$ormation of %alts$ormation of %alts


Reaction with Active Metals




Example:

!%! )eactions of Carboxylic Acids %&B $"* (




Car%o&yli# a#i!s rea#t with strong alkalis such as NaOH toform sodium carbox lates an! water


Reaction with Bases

Examples:





Car%o&yli# a#i!s also rea#t weak alkalis such as Na 1CO = or

NaHCO = to form sodium carbox lates 2carbon dioxide an!water






6his rea#tion serves as a test to distinguish carbox lic acidsand other acidic organic compounds

Examples:


!%! )eactions of Carboxylic Acids %&B $"*.(




!%! )eactions of Carboxylic Acids %&B $ .(

NaOH an!Na 1CO = #an %e"se! to se)arate ami&t"re ofal#ohols2 )henolsan! #ar%o&yli#a#i!s





Chec# $oint !"&Chec# $oint !"&

*a+ escribe how to separate a mixture of ben2oic acidand phenol in the laborator ,

Answer

!%! )eactions of Carboxylic Acids %&B $ .(

7a8 4o!i"m hy!rogen#ar%onate2 water an! !iethyl ether are

a!!e! to the mi&t"re. Ben=oi# a#i! rea#ts with so!i"mhy!rogen#ar%onate to form a water-sol"%le salt whi#h!issolves in the aG"eo"s layer. After se)aration %y the "seof a se)arating f"nnel2 )henol #an %e re#overe! %y !istillingoff the ether. 6o the aG"eo"s layer2 hy!ro#hlori# a#i! is

a!!e! to generate the %en=oi# a#i! whi#h #an %e e&tra#te! %y !iethyl ether. After se)aration from the aG"eo"s

layer2 %en=oi# a#i! is o%taine! %y !istilling off theether.




New Way Chemistry for Hong Kong A-Level Book 3B*:

Chec# $oint !"&Chec# $oint !"&

*b+ Outline how a mixture of butanone and ethanoicacid can be separated in the laborator ,

Answer

) y $ (




New Way Chemistry for Hong Kong A-Level Book 3B*1

) y $ (

*b+

!%! )eactions of Carboxylic Acids %&B $"*/(



New Way Chemistry for Hong Kong A-Level Book 3B*$

(c l chlorides are the most reacti$e amongst the#ar%o&yli# a#i! !erivatives

6hey #an %e )re)are! %y the "se of SOCl 12'Cl = or'Cl A in goo! yiel!s

$ormation of Acyl Chlorides$ormation of Acyl Chlorides

) y (





A#yl #hlori!es #an %e "se! to )re)are aldeh des 2ketones 2

esters 2amides an! acid anh drides in organi# synthesis

) y (

A#yl #hlori!es are e&tremely sensiti$e to moisture 2

therefore2 it m"st %e stored in anh drous conditions

h drol 2e rapidl to form carbox lic acids




New Way Chemistry for Hong Kong A-Level Book 3B**

A#i! anhy!ri!es #an %e )re)are! %y reacting ac lchlorides with carbox lic acids in the presence ofp ridine

6his #an %e "se! to )re)are mixed anh drides 7+ ≠ + 8or simple anh drides 7+ I + 8

$ormation of Acid Anhydrides$ormation of Acid Anhydrides

) y (





(c l chlorides react with sodium salts of carbox lic

acids to give a#i! anhy!ri!es

) y (




New Way Chemistry for Hong Kong A-Level Book 3B*,

Ammonia rea#ts with #ar%o&yli# a#i!s to form ammoni"msalts. 6he !ry salts are heate! to !ehy!rate to give ami!e

$ormation of Amides$ormation of Amides

6he %etter way to )re)are ami!es is reactingammonia or amines with ac l chlorides





Car%o&yli# a#i!s rea#t with al#ohols to form estersthro"gh condensation reactions

sterifi#ation rea#tions are acid-catal 2ed an!

re$ersible

$ormation of Esters$ormation of Esters





LiAlH * is a powerful reducing agent whi#h re!"#escarbox lic acids to primar alcohols in goo! yiel!s

&ed"ction with 'ithi"m (etrahydridoal"minate &ed"ction with 'ithi"m (etrahydridoal"minate

Example:

!%! )eactions of Carboxylic Acids %&B $"*'(




Example !"&Exam ple !"&

*a+ Complete and balance the following acid-baseeBuations)

*i+

*ii+

Answer

Solution:

%a( %i(

%ii(





Example !"&Exam ple !"&

*b+ raw the structural formulae for the products formedfrom the following compounds when the are reducedwith lithium tetrah dridoaluminate,

*i+

*ii+

Answer

Solution:

%b( %i(

%ii( 12C1 , C1 , C1 , C1 , 21





Example !"&Exam ple !"&*c+ Complete the following eBuations)

*i+

*ii+

*iii+

Answer

Solution:

%c( %i(

%ii(

%iii(

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" (




Both chlorine and ox gen atoms are electron-withdrawing gro")s2 th"s making the ac l carbon much

electron-deficient ac l carbon is a good nucleophilic site

&eactions of Acyl Chlorides &eactions of Acyl Chlorides

Chloride ion is a good lea$ing group whi#h iss"%stit"te! %y other atoms or gro")s easily

ac l chlorides are $er reacti$e





Ben=oyl #hlori!e is m"#h less rea#tive than ali)hati# a#yl#hlori!es

reduction of electron-deficienc on the ac l carbon !"e to !elo#ali=ation of ele#trons *resonance effect 8

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" +(




A#yl #hlori!es are hy!roly=e! %y water to form the parent

carbox lic acids an! hy!rogen #hlori!e

Reaction with Water

Examples:





A#yl #hlori!es rea#t with al#ohols to give esters an! HCl

Reaction with Alcohols

Examples:





(c l chlorides react with phenols to gi$e esters in thepresence of base as catal st

an alkaline me!i"m #onverts )henol to a )owerf"ln"#leo)hile2 phenoxide ion

Example:

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" ,(




(c l chlorides react with ammonia to form amides rapidl

Reaction with Ammonia and Amines

Example:





A#yl #hlori!es rea#t ra)i!ly with 1> an! $> amines to form N -" N " N - substituted amides res)e#tively

6he rea#tion takes )la#e at room temperature an! )ro!"#esamides in high ield

6his metho! is widel used in laborator for amides s nthesis





Chec# $oint !"!Chec# $oint !"!/xplain wh ethano l chloride must be protected fromatmospheric moisture during storage,

Answer

6his is %e#a"se ethanoyl #hlori!e rea#ts rea!ilywith water 7from atmos)heri# moist"re8 to formethanoi# a#i!.

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" 3(



New Way Chemistry for Hong Kong A-Level Book 3B,:

A#i! anhy!ri!es undergo h drol sis to form carbox lic acids

&eactions of Acid Anhydrides &eactions of Acid Anhydrides

Reaction with Water

Example:




New Way Chemistry for Hong Kong A-Level Book 3B,1

A#i! anhy!ri!es rea#t with al#ohols to form esters in the )resen#e of acid catal st

Reaction with Alcohols

Example:

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" *(



New Way Chemistry for Hong Kong A-Level Book 3B,$

A#i! anhy!ri!es rea#t with ammonia an! with 1> an! $>amines in the ways similar to those of a#yl #hlori!es

Reaction with Ammonia and Amines

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" *(




Examples:




New Way Chemistry for Hong Kong A-Level Book 3B,*

(mides are the least reacti$e among the #ar%o&yli# a#i!

!erivatives towards nucleophilic substitution reactions

NH 1 5 " NHR 5 or NR 1 5 are strong bases an! th"spoor lea$ing groups

&eactions of Amides &eactions of Amides





Ami!e "n!ergo acid and alkaline h drol ses to form

#ar%o&yli# a#i!s an! #ar%o&ylates res)e#tively

Acid hydrolysis:

Reaction with Water

Alkaline hydrolysis:




New Way Chemistry for Hong Kong A-Level Book 3B,,

Ami!es are !ehy!rate! %y heating with (*<

1: to form nitriles

Dehydration

sef"l syntheti# metho! for )re)aring nitriles that are

not a$ailable b nucleophilic substitution reactions

between haloalkanes and c anide ions





Ami!es rea#t with a solution of ;r 1 in NaOH or a solution of

Cl 1 in NaOH to give amines thro"gh a rea#tion #alle! Hofmanndegradation

6he res"lte! amines have one carbon less than original amides

Hofmann Degradation

Example:

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" .(




Ami!es are re!"#e! %y LiAlH * in !ry ether to

give !0 amines

Reduction with Lithium Tetrahydridoaluminate





A#i!-#ataly=e! hy!rolysis of esters is the re$erse reactionof esterification

&eactions of Esters &eactions of Esters

Acid cataly!ed Hydrolysis

Example:




New Way Chemistry for Hong Kong A-Level Book 3B:

When esters are refl"&e! with an alkali s"#h as Na<H2 the

#orres)on!ing alcohol and sodium salt of the carbox licacid are produced

Alkali-#ataly=e! hy!rolysis are irre$ersible

Al"ali cataly!ed Hydrolysis

Example:

!%' )eactions of the Derivatives of Carboxylic Acids %&B $" /(




4oa) is ma!e %y the alkaline h drol sis of fats or oils

7i.e. triesters8 to )ro!"#e sodium carbox lates 7i.e. soa)86he rea#tion is #alle! saponification





sters are re!"#e! to alcohols %y LiAlH*

Reduction with Lithium Tetrahydridoaluminate

Example:





Example !"!Exam ple !"!raw the structural formulae of the missing compounds ( to

.)*a+

*b+

*c+

Answer

Solution:

%a(

%b(

%c(






.)*d+

*e+

*f+

Answer

Solution:

%d(

%e(

%f(






.)*g+

*h+

*i+

Answer

Solution:

%4(

%h(

%i(

!% 5ses of Carboxylic Acids and their Derivatives %&B $" '(




;en2oic acid and its sodium salt "se! as foo! )reservatives

're$ent the microbial growth and spoilage

se! in oyster sa"#e2 fishsa"#e2 ket#h")2 non-al#oholi#

%everages2 fr"it F"i#es2margarine2 sala! !ressings2

Fams an! )i#kle! )ro!"#ts

As $ood )reser*ati*es As $ood )reser*ati*es

!% 5ses of Carboxylic Acids and their Derivatives %&B $" '(




As &aw materials for +akin )olymers As &aw materials for +akin )olymers

N lon->"> 2 2is a

condensation pol mer

t is a )olyami!e ma!e %y a!!ing Na<H #ontaininghexanedio l dichloride an! hexane-!">-diamine to CH 3CCl 3

!% 5ses of Carboxylic Acids and their Derivatives %&B $". (




Advantages o Nylon-

6,6rip dr easil

Not atta#k %y inse#ts easily

Resist creasing 7no ironing reG"ire!after washing8

se! for making ro)es2 threa!2 #or!s2an! vario"s kin!s of #lothing fromsto#kings to Fa#kets

7 l 2 2 i ) l





7er lene 2 2 is a )olyester

ma!e from acid-catal 2ed condensation pol meri2ation

of ben2ene-!" -dicarbox lic acid and ethane-!"1-diol

Terylene is used to make wash-and-wear garments




New Way Chemistry for Hong Kong A-Level Book 3B:

LiG"i! esters are wi!ely "se! as sol$ents for all-purposeadhesi$es 2thinners for paints an! nail $arnish remo$ers

As %ol*ents As %ol*ents





Jolatile esters often have characteristic sweet andfruit smells

6hey are "se! as artificial fla$ourings in food-processing industr

As $la*o"rin s As $la*o"rin s

An artificial flavouringmade of esters





Structure of ester Characteristicfla$our

Banana

A))le

A)ri#ot

(inea))le

Some esters and their characteristic flavours





Structure of ester Characteristic fla$our

+"m

/ra)e

Wintergreen

Some esters and their characteristic flavours (cont’d



The E D

a2 chemistry carboxylic acids and their derivatives

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