Transcript Document

10
General, Organic, and
Biochemistry, 7e
Bettelheim,
Brown, and March
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10-1
10 Chapter 10
Organic Chemistry
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10-2
10 Organic Chemistry
• Organic chemistry: the study of the compounds
of carbon
• organic compounds are made up of carbon and only a
few other elements
• chief among these are hydrogen, oxygen, and nitrogen
• also present are sulfur, phosphorus, and a halogen
(fluorine, chlorine, bromine, or iodine)
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10-3
10 Organic Chemistry
• Why is organic chemistry a separate discipline
within chemistry?
• historical: scientists at one time believed that a
“vital force” present in living organisms was
necessary to produce an organic compound
• the experiment of Wöhler in 1828 was the first in a
series of experiments that led to the demise of the vital
force theory
NH4 Cl + AgNCO
A mmonium Silver
ch loride
cyan ate
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heat
O
H2 N-C-NH2 + AgCl
U rea
Silver
chloride
10-4
10 Organic Chemistry
• The sheer number of organic compounds
• chemists have discovered or made over 10 million
organic compounds and an estimated 100,000 new
ones are discovered or made each year
• by comparison, chemists have discovered or made an
estimated 1.7 million inorganic compounds
• thus, approximately 85% of all known compounds are
organic
• The link to biochemistry
• carbohydrates, lipids, proteins, enzymes, nucleic acids,
hormones, vitamins, and almost all other chemicals in
living systems are organic compounds
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10-5
10 Organic Chemistry
• a comparison of organic and inorganic compounds
Organi c Comp ound s
Ino rg an ic Co mpou nds
Bond ing is almost entirel y co val ent
May be g ases, li quid s, o r so li ds
w ith l ow melti ng po ints (l ess
than 360°C)
Mo st are i nsol ubl e in w ater
Mo st are so lu ble i n o rg an ic so lv en ts
such as d iethy l ether, to luene, and
dichl orometh ane
Aqu eo us so lutio ns do n ot
condu ct el ectrici ty
Al most all burn
M ost have i oni c bo nds
M ost are sol id s w ith h ig h
melting po in ts
Reacti ons are usuall y sl ow
Reactio ns are o ften very fast
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M any are so lu ble i n w ater
A lmo st al l are i nso lubl e in
o rgani c so lvents
A queous sol uti ons cond uct
electrici ty
V ery f ew burn
10-6
10 Organic Structure
• structural formula: shows the atoms present in a
molecule as well as the bonds that connect them
• VSEPR model: the most common bond angles are
109.5°, 120°, and 180°
HH
H
C C
HH
Eth ane
(bond angles
109.5°)
H
H
Eth ylen e
(bond angles
120°)
H-C C-H
H-C-C-Cl :
Acetylene
(bond an gles
180°)
HH
Ch loroeth ane
(bond angles
109.5°)
H-C-O-H
C O
H
H
HH
Methanol Formald ehyde Methan amin e
(b ond angles (bond angles
(bond angles
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109.5°)
120°)
109.5°)
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H
:
H
H-C-N-H
:
: :
: :
H
: :
H-C-C-H
H
HH
H
C N
H
H
Methyleneimine
(bond angles 120°)
10-7
10 Organic Structure
• Among neutral (uncharged) organic compounds
• carbon: four covalent bonds and no unshared pairs of
electrons
• hydrogen: one covalent bond and no unshared pairs of
electrons
• nitrogen: three covalent bonds and one unshared pair
of electrons
• oxygen: two covalent bonds and two unshared pairs of
electrons
• a halogen: one covalent bond and three unshared pairs
of electrons
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10-8
10 Functional Groups
• Functional group: a part of an organic molecule
that undergoes chemical reaction
• Functional groups are important because
• they undergo the same types of chemical reactions no
matter in which molecule they are found
• to a large measure they determine the chemical and
physical properties of a molecule
• they are the units by which we divide organic
compounds into families
• they provide the basis on which we derive names for
organic compounds
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10-9
10 Functional Groups
• Five important functional groups
Family
Functional
group
Example
N ame
Alcoh ol
-OH
CH3 CH2 OH
Eth anol
Amine
-NH2
CH3 CH2 NH2
Eth anamin e
Ald ehyde
O
-C-H
O
CH3 CH
Eth anal
Ketone
O
-C-
O
CH3 CCH3
Aceton e
Carb oxylic acid
O
-C-OH
O
CH3 COH
Acetic acid
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10-10
10 Alcohols
• Alcohol: contains an OH (hydroxyl) group bonded
to a tetrahedral carbon atom
:
R
R-C-O-H
R
Function al group
(R = H or carbon
goup
:
HH
H-C-C-O-H
HH
S tructural
formula
CH3 CH2 OH
Cond ensed
stru ctural
formu la
• may be primary (1°), secondary (2°), or tertiary (3°)
CH3 -C-OH
H
CH3 -C-OH
CH3
CH3 -C-OH
H
A 1° alcohol
CH3
A 2° alcohol
CH3
A 3° alcoh ol
H
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10-11
10 Alcohols
• Problem: draw Lewis structures and condensed
structural formulas for the two alcohols of
molecular formula C3H8O
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10-12
10 Alcohols
• Problem: draw Lewis structures and condensed
structural formulas for the two alcohols of
molecular formula C3H8O
• Solution:
Cond ensed stru ctural
formulas
HH H
H-C-C-C-O-H
HH H
CH3 CH2 CH2 OH
: :
Lew is stuctu res
A p rimary alcohol
H
H:O: H
OH
H C-C-C-H
HH H
CH3 CHCH3
A secon dary alcohol
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10-13
10 Amines
• Amine: a compound containing an amino group
• the amino group may be primary (1°), secondary (2°), or
tertiary (3°)
CH3 NH2
CH3 NH or (CH3 ) 2 NH
Methylamin e
(a 1° amine)
CH3
D imethylamin e
(a 2° amine)
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CH3 NCH3 or (CH3 ) 3 N
CH3
Trimethylamin e
(a 3° amine)
10-14
10 Amines
• Problem: draw condensed structural formulas for the
two primary amines of molecular formula C3H9N
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10-15
10 Amines
• Problem: draw condensed structural formulas for the
two primary amines of molecular formula C3H9N
• Solution:
NH2
C-C-C-NH2
C-C-C
Th e three carbon s may
be bond ed to n itrogen
in tw o w ays
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CH3 CH2 CH2 NH2
NH2
CH3 CHCH3
Add s even hydrogens to give each
carbon four b on ds an d give the
correct molecu lar formula
10-16
10 Aldehydes and Ketones
• Both contain a C=O (carbonyl) group
• aldehyde: contains a carbonyl group bonded to a
hydrogen; in formaldehyde, the simplest aldehyde, the
carbonyl group is bonded to two hydrogens
• ketone: contains a carbonyl group bonded to two
carbon atoms
RO
R C-C-H
O
CH3 CH
R
Fun ctional A cetaldeh yde
grou p
(an aldehyde)
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RO R
O
R C-C-C R CH3 CCH3
R R
Functional
group
Acetone
(a ketone)
10-17
10 Aldehydes and Ketones
• Problem: draw condensed structural formulas for the
two aldehydes of molecular formula C4H8O
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10-18
10 Aldehydes and Ketones
• Problem: draw condensed structural formulas for the
two aldehydes of molecular formula C4H8O
• Solution:
• first draw the functional group of an aldehyde and add
the remaining three carbons; these may be bonded in
two ways.
• then add the seven hydrogens necessary to complete
the four bonds of each carbon.
O
CH3 CH2 CH2 CH
or
CH3 CH2 CH 2 CHO
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O
CH3 CHCH
CH3
or
CH3 CHCHO
CH3
10-19
10 Carboxylic Acids
• Carboxylic acid: a compound containing a -COOH
(carboxyl: carbonyl + hydroxyl) group
• in a condensed structural formula, a carboxyl group
may also be written -CO2H.
O
O
CH3 COH
RCOH
Fu nctional
Acetic acid
group
(a carb oxylic acid )
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10-20
10 Carboxylic Acids
• Problem: draw a condensed structural formula for the
single carboxylic acid of molecular formula C3H6O2
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10-21
10 Carboxylic Acids
• Problem: draw a condensed structural formula for the
single carboxylic acid of molecular formula C3H6O2
• Solution: the only way the carbon atoms can be written
is three in a chain; the -COOH group must be on an end
carbon of the chain
O
CH3 CH2 COH or CH3 CH2 COOH
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10-22
10 Chapter 10 Organic Chemistry
End
Chapter 10
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10-23