Download TT T p

; - ; t . -, t Compoundsthatcontainthe
Crqanic Acids.
f,,,nltional group R-COOH are called organic
a'cids,or carboxylic acids.The structuralformula
ior the acid, or carboxyl,group is shown in Figure
9-6. Organic acids are named from the corresponding alkanesby replacing the final "e" u'ith
tle ending "oic" and adding the u'ord "acid."
The first two members of this series are methanoic acid, HCOOH, and ethanoic acid,
CH3COOH. They are better known by their common names, formic acid and acetic acid (see Figure 9-7).
(
,P
\"
general
structureof an organicacid.
The
Figure 9-6.
.\
H_-C.
//
.o
HOH
Figure 9-7. Structurai
acetic acid.
formulas
f /,o
9-c(
rl' o
of formic
acid
and
An example of a long-chain organic acid is
stearic acid, CrzHs;COOH, also called a fatty
acid. Fatty acids are related to fats and are disc us se d o n page 74.
QUESTIONS
l. . Which is the formula for ethanol?
H
(1 )H-
I
C-oH
I
H
TT
| I
'\
(o it-Q-Q-oH
\;' - I |
HH
o
(2)H-C\
,//
'oH
T p
,oru-t-{
| \o "
H
2. The functional group -COOH is airvays found in
an orsanic /C acid (2) alcohol (3) alkane (4)
\-"
rlku.rJ
3. Which.^compound has the general formula
R-OH?
I(f) metha.tol (2) methane (3) methanoic
acjd (4) pYopene
//\
4. What is the formula for pentanol? (1) CsHl, (A )
( 3) C4H1o ( 4) c 4 H s O H
c5Hl ro H
5. A .particular arrangement of atoms that describes
Organic ChemistrY
,/f\
for (L) methanol (2)i ethanoic acid (3) methanoic
- (4)
acid
ethanol
group atB. Compounds in which there is an -OH
tached to a carbon atom at the end of a hydrocarbon
chain are called i I ) orsanic acids (2) alkanes (3) aro m a t i c c o m p o u n d s ' @ R r i n 't r r v a l c o h o l s
CF ORGANIC
REACTICNS
COMPOUNDS
Reactions of organic compounds generally
occur more slou'ly than do reactions of inorganic
compounds. Organic reactions often involve.only
the functional groupi of the reacting species. This
Ieaves the greiter part of the reacting molecules
reiatively unchanged during the course of the
reaction.
Ace tr c a cid
( e th a n o ic a cid )
I ormrc a c r o
(met hano i c a c i d )
the propertiesof a.seriesof compounds,Suchasorganic
acids or alcohols,is cailed a (1) carboxyl group (2)
,-\
^
group (4) hvdroxvl
functional
methyl ero.rO($
group
6. The thi rd memberof the hompl ogousseri esof pri mary alcohois is (1) ethanol @furonunoi (3) butanol (4) propane
7. Acetic acid, CHTCOOH, is the common name
Substitution Reactions.
in
Reactions
which one kind of atom or group of atomsis replaced by anotherkind of atom or group of atoms
are called substitutionreactions.Except for combustion and thermal decomposition,reactionsof
saturated hydrocarbonsare usually substitution
reactions in which one or more hydrogen atoms
are replaced.
When a halogenatom replacesa hydrogenatom
in a saturatedhydrocarbon,halogen substitution
is saidto haveoccurred.The products,calledhalogen derivatives,are named usihg a standardsystem. The suffix comes from the name of the
straieht-chain alkane with the same number of
carbon atoms.The prefix shows which atoms or
functional'groups have been added and the carbon atom in the straight chain to'which they are
attached.A few gxamplesof halogen derivatives
are Shown.in Figure 9-8 on page 74. Note that
structures(b) and (c) are isomers.
Addition Reactions.
The additionof one
asX,.to an unsaturated
or more atoms,"des.ignated
at
a
double or triple b^ond
molecille
hydrocarbon
is called an addition redction. As a result of addition reactions, the multiple bonds are broken
and unsaturated molecules become saturated
(see Figure 9-9, page 74).
Addifion reactions have a high rate of reaction.
Becauseaddition reactionstake place more easily
than do substitution reactions, unsaturated comoounds tend to be more reactive than are satuiated compounds.For example, becausealkynes
are more unsaturatedthan alkenes,they are generally more reactive than alkenes'
73
.E
trr
C]HH
HCIH
ri r
H-C-C-C-H
ttl
CI-C-C-C-H
llr
lll
HHH
HHH
( b)
I , l- dic hlor opr o p a n e
( a)
2 -ci r l o ropr opane
The hvdrolysisof fatsby
Saponification.
ClHCl
bases i s cal l ed saponi fi cati on. S oap, w hich is a
sal t of a .l ong-chai n organi c aci d, i s produced
when a fat (a glycerol stearate ester found in ani mal fat) i s saponi fi ed by hot al kal i (see pa ge 76) .
rtl
H-C-C-C-H
lll
HHH
C 3H s(C rzH 3sC OO)3 + 3N aOH ->
i,s di"hlltlp.op"'.'"
fat
Figure 9-8. Structuralformulas of three halogen der iv at iv es .( T he n u m b e rsi n th e n a m e s o f th e hal ogen
derivativesidentify the specificcarbonatomsto which
the halogen atoms are attached.)
I
C-*Xz
ti ons to i ncrease the yi el d of ester by act ing as a
dehydrating (water-removing) agent.
N { any esters have pl easant aromas. The scent s
of many fruits, flowers, and perfumes are due to
esters. Fats are esters produced by the r eact ion
ofgl ycerol , a tri hydroxy al cohol (see page 7 6) , and
l ong-chai n organi c aci ds (see page 73).
al kal i
3C rzH g;C OON a + C 3H5( O H) 3
soap
gl y c erl ne
In an excess
Oxidation.
of oxygen,saturated
hydrocarbonsburn completelyto form carbon
dioxide and water.
li
--. -C-C-
CHn + 2O2 -' COz + 21120
ll
XX
Figure 9-9. An addition reaction.
The burning of hydrocarbonsin a limited supply
of oxygenma;' producecarbonmonoxide(CO) or
carbon (C).
2CH4 + 3Oz --+ 2CO + 4H2O
Addition of Flalogens. Halogen derivatives can
be formed by the addition of halogens to unsaturated compounds, as well as by substitution reac t ions , T he a d d i ti o n , o f c h l o ri n e a n d bromi ne
takes place at appreciable rates, even at room
temperature. Iodine is less reactive than chlorine
and br om ine i n a d d i ti o n re a c ti o n s .
F t r y dr ogenati o n . T h e a d d i ti o n o fh y d ro g en to an
uns at ur at ed m o l e c u l e i s c a l l e d h y d ro g enati on.
Hydrogenation reactions usually require the
pr es enc e of a c a ta l y s t a n d e l e v a te d te m p eratures.
The compounds formed are usually saturated
hy dr oc ar bon s .
Fermentation.
CH* + Oz--+ C + 2H2O
Polymerization.
Large molecuies can be
formed from smaller molecuiesby polymerization reactions.The largemoleculesformedby poIymerization consist of chains of repeating
smallersubunits.Suchlargemoleculesare called
polgmers.Syntheticrubbersand plastics,suchas
polyethylene,are polymers.Naturally occurring
polymers include proteins. starches.and many
other chemicalsproducedby living organisms.
QUE'SrfOr{s
The processin which en-
zymes from living organismsact as catalystsin
the partial breakdown of an organiccompound is
called fermentation. Ethanol is a product of the
fermentation of sugar(glucose)by yeast.The enzyme involved is calledzumase.
CeHrzOo -----------.+
2C2H'OH + 2COz
sugar zymase ethanol
jtrtff:
l. The complete combustion of any hydrocarbonin
excessoxygenproduces (1) CO and Hz (2) COz and
H 2 (3) C O and H zO dZ) C O, and H zO
2. The correct name f#the compound shown below
i s (1)_ 1,3-di chl oropentane(2) 2,4-di chlor opentane fiil1,3-dichlorotutane (4) 1,i-dichlorobutane
\JZ
ClHCI H
Esterification.
The reaction of an organic
acid with an alcohol to form an ester and water
is called esterification.Esters are covalenr compounds with the generalformula RCOOR'. The
generai equation for esterificationis
RCOOH + R,OHe2RCOOR,+ H2O
orga.4rc
a lco h o l
e ste r
water
Esterificationproceedsslowly and is reversible.
Sulfuric acid is often used in esterificationreac-
74
lltl
H- C -C-
tl tl
C-C-H
HHHH
3. In the preparationofan ester,the yield ofthe ester
is increaselLbythe addition of (1) water (2) sodium
chl ori de { 3))sul furi c aci d (4) sodi um hydroxide
4. The rei cti on C gH s + C l 2 + g.gt6l + HCI is an
exampi e of @ substj tuti on (2) addi ti on (3) est er ification (4) hydrogenation
Reaieuing Chemistry: Unit 9
I
5. Which equation represents an esterification reaction?
(L) C6HreO6 -; 2C2H5OH + 2COz
( 2 ) CsHlo * H2 -+ CsHrz
{3 ) C rHn - Clz --* C3 H?C I + HCI
r{}n-coou + cH3oH--+HCoocH3 + HoH
Bi u/ni.h structuralformularepresentsthe productof
the reaction between ethene and bromine (Brz)?
HH
H
I
tr) Br---!-Br
II
H -_?-C -H
ll
Br
I
H
Br
with two -OH groups are dihydroxy3lcohols'
with thiee -oH groups ar-e'trihvdroxv
;Jih;;
s.
alcohol
*ef"oftoft are also classified a'ccordingto -the
carbon chains attabhedto the carbon
"t
""-L"i
atom with the -OH groups'
Alcoliols
* Monohydroxy Alcohols.
monony'dio"y
that have one --OH group are
alcohols.
."'
* Frimarv Alcohols. Primarymop'6{yd'o*yaicohols *ere dis"ussedon paggif? In primary
the -OH group-is,sf the last carbon
"i""tt"f,
The-general for;i"*trf in" hydrocar*bo"
"4ui1
mula for a primary alcohpl'is R-CHzOH'
SecondaryAlcohqlS. Alcohols in which the
tlie -oH sroup is bonded to
"".b;;;i;;'with
secondary,4lat" called secondary-4li*"
"t" "ill"d
"lfr"i""rboq.atoms
"ir-r"t
the -OH.gro'up is
seco,ridaryalcohols-,
In "".uo",6to-t
cohols.
(see
noilo"ut"d at Lheend ofa hydrocarbonchain
f f *"."-S- i.01.The general fo rmula fo-rd'econdary
*
HBrBr
H Br
(3) t l
"-?-1-u.
HH
lll
o H-9-9-?-'
ltl
HHH
In an aqueous solution, whicn- compound wili b e
7.
cH3cooH
acidic? @I
csHs(oH)g (4)cHsoH
(2)
cH3cHzoH (3 )
The reaction CH4 + Br2 -+ CHgBr * HBr is an
of (1) addition (2)hvdrogenation @sub"*".rrpl.
stitution (4) PolYmerization
9. A reaction between CH3COOH and an alcohol
The alcoholused in
oroduced the esterCH3C'OOCH3.
-($. 'CH.OH (2)
C2H'OH (3)
*^r
the reaction
C3 H TOH ( 4) CaHs O H
10. Which of the following structural formulas repres e n ts2 ,2- dic hlor oP r o Pa n e ?
r\Ijrriu
where\3tid
wnere
ttrt(zLHUrl.
alcohols.,i's nrnrcfiou,
"i"%rr"tr,rt
gto"it
;;;.b'";
;;i.;fi t-;;tpi'ol,
(seeFigure 9-lI).
8.
H
-Re
,/"'
Fisure 9-10. The general structure of gecbndarY
alcohols
./
-t"/
H O HH/
Hcrcl
T:'1'T
(,)
(2)H-c-c-c
H-A-J-I-.-'
*)H-J-l-tr-"
I
I I I "
AAH
R2
r\2 arehv-
secondary.alAn exam-ple
"gf'a
alcohoI
op
cali
also
9d"is ropvl
"_i_IdL"
-[" ' " l l
,,'H H
HHHH
H
2-propanol
H C IH
_ ttr
@n-q-9-9-H
rrrllll
HCIH
HCIHH
l tli
(a)rI-_Q'c-c__c-H
HCIHH
11. Which kind oi reaction produces ethanol as one
(2) saof t}e principal products? (l) elterification
ponification (3) neutralization- (!)fermentation
iZ. Which compound will-updergo a substitution reCHl (2) CzHa (3)
with chlorine? (9
^"tto.,
CsHn (4) C4H8
"/
{< CLASSESOE',ALCOHOLS
Alcohols are classifigdaccordingto the number
of -OH groups theiy'contain' Alcohols with one
g.6"n a.erdo"ohydroxy alcohols, those
-Off
/
Organic Cherrlistrg
Figure"g-11. 2-ProPauol
(Note tirat the 0H glottP is on tire sec
carbon.)
in which the caris
bonded to three
-OH
bon atorn with the
alcohols.
tertiary
led
are
atoms
other carbon
is
alcohol
tertiarY
a
r
general
'foqnuia
The
formulait t!:y:
R;Rrfi;Con. rrt'esrdrctural
11
tig,i*'g;-iz. nt,#^"tpt" of.atertiarv1!"h"":^:'
*hi"h-it also know:r as tertlp.opdnol,
;-;;thyl
ioH
,fl
I
il
Rr-Q-Rn
il
'Rs
Figure 9-12. Structural formula of tertiary alcohols'
' tJ
H OHH
H
l l l n 'l '
Q-Q-Q'jH
I
| -'"1
,
".rl,1,,
,r"-T-"
resent a hydrogen atom or an-y- hydrocarbon
fu:rctional
sroup. The structu,"i--iot*"I" of the
AI-
il;;
it tho-" in Figure9-16'
from the correPPondingal"a1'" Thus'
t"pr""i"gitte final "e" with
k;;;;;"iitti -ti.*bti
oi irt" group is methanal'
iri"
;;';;;;;
3""h;1;;"ilia"irti"'
ilbd6:;i;l"n
it
^tto
H
.H
aldehyde'
Figure9-16. Functionalgroupof an
Fieure 9-13. Tertiary butanol, or 2-methyi-2-propanol'
is i tertia ry alc ohoi.
;;il""ffi;J"ir'irt""
tl)
Figure.n
glvcol(see-
/P
-"\r:'
2-methYl-2'ProPanol
* DihydroxYAlcohols:
"-6u-_gtoups
know-n'as dihvare9:T*::"d'r:l:f,t""*t:i*"
""l"oholt,or as glvcols'The
fr;;;:".'iiltvati".,
commost important glycol is 1'2-ethanediol'
knownasformaldehvde'
pJ-',vl::I:l:,$;:,
or
iH.i:*ft,^,t*Y|*:
groups are easl l y OX
ure 9-l B ).
and antl E t hy iene g l y c o l i s u s e d a s a c o o l a n t
f r eez e in c a rs '
I
I
H-C-OH
H-C-OH
I
is the
Figure 9-I4. Ethylene glycol, or 1,2-ethanediol'
alcohol'
dihvdtoxY
most widelY o."d
x Trihvdroxv Alcohols' - compounds
areknownastrigroups
;;";i;l'islh;"J-os
most impor;t trihvdric, alcoholl'-The
il;;;;",
is 1'2,3-propanetriol' or
;i;"ii"l
;"*'il'h;;;;;t
elvcerol (see Figure-g-ft' Fats q9 synthesized
acids' clyceroi is also
F.Jti."-i""'"tJt
"t-Jotg^nic
of faidigestion in aninrals'
^t "."J'"t"a"ct
I
I
+ HzO
+ oxidizing-+ R-C:O
agent
water
aldehYde
primarY
alcoho]
Fi gure 9-17. Synthesisof an aldehYde'
p
H
-n-J:o + oxidizing
agent
bU
to form an orFigure 9-18' Oxidationof an aldehyde
ganrcaclo.
o
H-C-OH
I
H
1,2,3-ProPanetriol
Glycerol
is the
Figure 9-I5. Glycerol, or 1,2,3-propanetriol'
alc
onor
'
most imp or t ant t r ihy dr ox y
* OTHERKINDSOF ORGANIC
COMPOUNDS
/o
R-Ci
or gal l l c
ac i d
al dehyde
I
".^i
.//
H-C-OH
H--C-OH
the genCompounds.with
AldehVdes.
can repR
aldehydes'
are
for-trt'un-CHO
,,.
' ..!,
Rr-C-R,
ofketones'
Figure 9-19. The general structure
kno wn as aceP ropanone' w hi ch i s commonl y
tI:
member ,of
simplest
useu
^ta
wldely
l
s
A
cetone
(see Fi gure 9-20)'
.";;.:;' il"
t,,.'-
.4..i
..-=
f
I
,.-:*
,,,.€
.;i,l,i
H
Beneral
Compound5
* Ketones.
-rvith .the
R3 arg hyRt.and
kitones:
are
RTCORz
formula
rl!"t" 9-19 shows the func;;;;.b";'gto"pt
tional group of ketones'
I
::'::]:l:n
a"a4
.' .:':l
tt
EthYlene glYcol
.
,,#
H.
H
I
n
' ,.:.s>j
liiF
. .:' :j:::i?
R-C-OH
*
,'..i
,+ #
ca.n!e svnthesizedUy tlt" oxidation
Aldehy'des-
h.ti
group
as a sol vent.
TfrT
"-T-.-T-H
HH
A cetone
Figure 9-20. Acetone,or propanone'
Reaieuing Chemistrg: Unit 9
,+
a'i
t;
':a
..::
J
t-,
Ketones can be synthesized by the oxidation of
sec o n d a ry alc ohols ( s ee Fi g u re 9 -2 1 ).
oHo
I
* oxidizing -, Rr-d-R2
Rr-C-Rz
+ H2O
agent
sec ondaly
alc ohol
wa te r
ke to n e
Figure 9-21. Synthesisof a ketone by the oxidationof
a s e co n d a ryalc ohol.
Compoundswith the generalfor* Ethers.
mula RrOR2 are ethers.The Rr and Rz represent
any hydrocarbon groups.The best-known ether
is diethyl ether (CzHsOCgHs),which has been
used as an anesthetic.
Ethers can be synthesizedby the dehydration
of primary alcohols(see Figure 9-22).
Rr-oE
* ,Addition Reactions. Pol;'merization that results from the joining ofmonomers of unsaturated
compounds is called addition polymerization'
The reaction occurs by the "opening" of double
or triple bonds in the carbon chain (Figure 9-24).
Vinyl plastics, such as polyethylene and polystyrene, are formed by'addition polymerization'
nCzHq --+ (-CzHa-)"
Figure 9-24. Somepolymersareproducedby addition
pol l meri zati on.
+ HzO
+ R;IOHI-+ Rr-O-R2
plima l y a l c o l - r o l s
reaction may be repeated many times to produce
long-chain polymers. For polymerization to
occ,tr, the monomers involved must have at least
two functional groups. Materials formed by condensation polymerization include silicones, polyesters, pol yami des, phenol i c pl asti cs, and
n) rons.
* QUESTfONS
wa te r '
e th e r
Figure 9-22. Dehydration of primary alcoholsto produce ether.
A polymer is a largemolecule
* PolVmers.
that is c5mposedof many repeating smallerunits
called monomers. Naturaily occurring polymers
include starch, ceilulose, proteins, and DNA'
and
nylon
Synthetic polymers include
polyeLhylene.
^
The processin which monomersarejoined together lo form polymers is called polgmerization.
Folymerization may involve condensation or
addition.
L Which compound is a dihydroxy alcohol?
(2) C3H5(OH)3
(1)A I(OH )3
(3)C a(oH )z
@,czHa(oH):
2. Which compound i s a tri hydroxy al cohol ?
glyceroi (2) butanol (3) ethanoi (4) methanol
10
3. Which structural formula below represents
ethanediol?
@
HH
HH
ll
(r) H-q-9-oH
ll
T"I'T
T,I4,,
(3) H- C-C-C-H
rtll
H o-C- C - o l H
HH
llll
+ H o l -C -C -o H
rlll
lll
(4) H-C-C-C-H
rll
HOHH
HHH
lll
(2) H-C-C-C
rll
I
H
HHH
HO
H
H
+ HzO
HH
dirner
Figure 9-23. Monomers can b e
tion poiymerization.
Organic Chemistrg
(I) H-C-C-OH
HH
llli
HO-C-C-O-C-C-OH
HH
slrl?
)r'loltonte r
lnononlel'
HHO H
an aldehyde?
4. Which structuralformula represents
HH
HH
HH
*
HO O H
HH
* Condensation Reactions. Polymerization
that resuits from the bonding of monomersby a
dehydration reaction is called condensationpolymerization (seeFigure 9.23).The condensation
F {H
ll
(iz} H-c-Q-H
\-/ll
water'
jo in e d
b y co n d e n sa -
*lll
{rsl, H-C-C-H
\./
|
H
(4) H-
H
I I
I I
H H
C \ Cc-o )H
tt
T\W
5. Which is the structural formula for glycerol?
.H
(1 )
H
I
I
I
H-C-OH
I
H
I
H
OH
I
n ,!,!
(2) H-9-OH
H-C-OH
I
( 3) HO-C-OH
(4) H-Q-9/-'Q-Q-H
H
.
I
'"@ rt-q-oH
,.."1
,H-q-oH
H
- -*Q-=*An-alde+ryde-ca:r-be--oxidize&tc{om=tt)-:a*ke=**-- tone €)-an-ester-{3)@-_
--9. *Whi"h
formula represents a ketone? (i)
(2) crHscoOCH
cH3cocH3
(3) C2H5COBf
(4) C H 3C H O
I0. The reaction representedby the equation below
(2) fermentation (3) esterifiis
.(t) Btonification
catron (fl polymerization
l' ,
H-C-OH
I
ll.
H
Which is t}le general formula for an ether?
.
ol
(I) R-OH
nC zH + -+ (-C zH + -)"
e\ R-<
Which is the formula of methanal?
//,o
G'ils-(
\
H
\
H
I
(a I{-9-oH
I
H
o
@ *,-*on
(3) H-\
,7, Which is a tertiary alcgholl
ll"oq?H
/i:DH-o4-C]"
'
/l
| |
'HHH
7B
H
(4)o,-8-^,
H
OH
,,,n-L{-"
rll
1
I
/o
I
O HO H
(-1)eHseeorf-{2} CH'iorr"-'-^-*-.
(4) H-f-H
I
H
-{a.rIICooH"-.-€fcH.scHQ_.
Reoieuing ChernistrE: Unit I