Transcript Chapter 22

Chapter 22
Organic Chemistry!!!!!
Chapter 6 in rxn workbook
Chapter 16 in PR
1
Organic Chemistry Is…..
 The study of carbon
containing compounds
and their properties
 Organic compounds are
typically in chains or
rings
 All organic molecules
are produced by living
things/systems
2
Vocabulary
 Chain
 Parent chain and
substituent
3
The Name Game …again
 Alkanes = hydrocarbons (chains of C and H)
 All bonds are single i.e “Saturated”
 An alkane is a hydrocarbon in which each
carbon atom is bonded to four other carbon
or hydrogen atoms.
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10 “normal” alkanes
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The Rest
Pentane
Hexane
Heptane
Octane
Nonane
Decane
C5H12
C6H14
C7H16
C8H18
C9H20
C10H22
A note on Boiling Point:
BP Octane
C8H18
< Nonane
C9H20
More C = more bonds to break and more energy
required.
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Isomers
 Same number and
type of molecules
but bonded in a
different location
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Draw all isomers Pentane
2
1
4
3
5
8
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IUPAC
International Union of Pure and Applied Chemistry
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Rules for Naming Alkanes
 Read Page 1061
 For chain alkanes beyond butane add the
suffix –ane to the Greek root for the number
of carbons
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For Branched alkanes find the longest
continuous carbon chain and use this name
as the base
(a). If two chains of equal length are present,
choose the one with the more branch points
as the parent.
12
 When alkane groups appear as substituent
groups they are named by dropping the
-ane and adding –yl.
 For example CH3 (methane) = methyl . C3H7
is called propyl
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 The position of substituent groups are
specified by numbering the longest chain of
carbon atoms sequentially starting at the end
with the closest branching.
C
C-C-C-C-C-C
1 2 3 4 5 6 correct numbering
6 5 4 3 2 1 incorrect numbering
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Last rule!
 The location and name of each substituent is
followed by the root alkane name.
 Substituents are listed in alphabetical order
and the prefixes (di, tri,) are used to indicate
multiple identical substituents.
 A number denotes which carbon that
substituent is boned to.
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Example
CH3
CH3 – CH2 - CH – CH2 – CH2 - CH3
1
2 3
4
5
6
3 - methylhexane
Smallest number for substituent
Substituent name
Parent chain root name
Hyphen between number and substituent name
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Try some
 Draw all structural isomers or C6H14
1. Start with the longest chain and then
rearrange the carbons to form the shorter
CH3-CH2 -CH2 -CH2 –CH2-CH3
1
2
3 4
5 6
Hexane
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Take one carbon out of the chain and make it a methyl
substituent
CH3
CH3-CH2 -CH -CH2 –CH3
1
2
3
4 5
CH3
CH3-CH –CH2 -CH2 –CH3
2 - methylpetane
3 - methylpetane
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Next take two carbons out of the chain
CH3
CH3-C –CH -CH3
CH3
1 2
3
4
CH3 CH3
CH3-CH –CH -CH3
1 2
3
4
2,2-dimethylbutane
2,3-dimethylbutane
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Write the structure for each of the
following compounds
 4-ethyl-3,5-dimethylnonane
(note the substituents are in alphabetical
order separated by a dashed line)
 4-tert-butylheptane
 (see your cheat sheet for tert structure)
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4-ethyl-3,5-dimethylnonane
1
4
9
21
4-tert-butylheptane
1
2 3 4
5
6
7
CH3-CH2-CH2-CH-CH2-CH2- CH3
H3C-C-CH3
CH3
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Reactions of Alkanes
 Combustion reaction
 Substitution reactions
 Dehydration reactions
 page1065
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Cyclic Alkanes
Add Cyclo to the number of carbons present
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25
Naming cyclic structures with
substituent
 Give substituent the lowest number possible
(can start with one this time)
 If more than one substituent is present
number in alphabetical order insuring that all
substituents have the lowest possible number
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Homework
Read Page 1066 sample exercise 22.4 naming
cyclic alkanes
Do page 1100 #’s: 15, 17, 19, 20,
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22.2 Alkenes and alkynes
 Hydrocarbons that contain carbon carbon
double bonds.
C2H4
C2H2
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Rules for naming Alkenes
 Root hydrocarbon chain ends in –ene
methene
Ethene
Propene
butene
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 In alkenes with more than three carbons, the
location of the double bond is indicated by the
lowest numbered carbon atom INVOLVED in
the double bond.
CH2= CHCH2CH3 1-butene
CH3CH=CHCH3
2-butene
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Double Bonding
σ sigma bond
π Pi bond
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Isomers of Alkenes
Cis:
H on
The same side of
The molecule
Trans:
H on
opposite sides of
the molecule
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34
Practice naming
Find the longest chain
and number it in the
direction that gives the
double bond the lowest
number.
Identify if the molecule is
cis or trans
4-methyl-cis-2-hexene
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Alkynes
 Unsaturated hydrocarbons containing a
carbon-carbon triple bond.
 The simplest alkyne is C2H2 called acetylyne
 In a triple bond there is one sigma bond and
two pi bonds.
 Replace the –ane ending –yne
 Alkenes and alkynes can exist as ringed
structures as well.
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37
2-methyl-3-heptyne
Due to the triple bond
there is no H to be cis
or trans
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Homework
 Pg 1101 #’s : 21, 22, 23,24
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Aromatic Hydrocarbons
 A special class of cyclic unsaturated
hydrocarbons.
 The simplest is benzene C6H6
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Resonance of
Benzene
41
Nomenclature
 If there is more than one substituent numbers
are used to indicate position.
1,2,4-trichlorobenzene
2,4,6-trinitrotoluene (TNT)
42
FYI
Toluene
or
Common name
Methylbenzene
IUPAC name
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 Some systems use prefixes for substituent
position.

Ortho (o) for two adjacent substituent
meta (m) two substituent with 1 carbon between
them.
para (p) two substituents opposite of each other
When benzene is used as a substituent it is
called a phenyl group.
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0-dichlorobenzene
m-dichlorobenzene
p-dichlorobenzene
45
Give substituents lowest number and place
in alpha order.
o-bromochlorobenzene
p-bromochlorobenzene
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Complex aromatics pg 1072 table22.3
Naphthalene
Anthracene
Phenanthrene
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Homework
 25, 27(skip d) ,28, 29, 37, 38
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22.5
hydrocarbon Derivatives
 Molecules that are fundamentally
hydrocarbons (C&H) but have additional
atoms or groups of atoms called functional
groups
 Functional Group: functional groups are
specific groups of atoms with in molecules,
that are responsible for the characteristics of
those molecules
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Common functional groups pg 1077
table 22.5
Class
 Halohydrocarbons
(x = F, Cl, Br, I)
 Alcohols

Ethers

Aldehydes
General Formula
RX
ROH
ROR
R and R’ = hydrocarbon fragments
O
R C H
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The Common Functional Groups
Class
Ketones
General Formula
O
R C R'
Carboxylic Acids
Esters
Amines
O
R C OH
O
R C O R'
RNH2
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53
Alcohols
 Have a hydroxyl group
 Replace final -e with –ol
 Position of –OH group is specified with a
number (smallest number goes to
substituent)
 Classified according to how many
hydrocarbon fragments (R) they have
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See table 22.6 for common alcohols
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Example: Name and state 1º, 2º, 3º
 Number the chain
Giving OH smallest
number
Note carbon that –OH is
attached to has –CH3
and a -CH2CH3 groups
attached.
Thus it is a secondary
alcohol.
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Name and state 1º, 2º, 3º
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3-chloro-1-propanol
Primary alcohol
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Phenol
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Aldehydes and Ketones
 Aldehydes and ketones contain carbonyl
groups.
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Ketones
 Carbonyl group bonded two carbons atoms
 Ex: acetone
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Aldehydes
Carbonyl group is bonded to at least one
hydrogen
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Naming Aldehydes and Ketones
 Aldehydes: Named from parent alkane and removing
the e and adding –al.
 Ketones: The final e is replaced with –one.
 In both cases a number indicates the position of the
carbonyl group where necessary.
 Note: since aldehyde functional group is always a the
end of the carbon chain the aldehyde carbon is
always assigned as number 1 for referencing the
substituent position in the name.
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Naming Aldehydes and Ketones
 The parent chain selected must contain the
carbonyl group.
 Number the carbon chain, beginning at the
end nearest to the carbonyl group.
 Number the substituents and write the name,
listing substituents alphabetically.
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3
65
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Carboxylic Acids
 Carboxylic Acids have a carboxyl group.
RCOOH
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Naming carboxylic acids
 Name from parent alkane by dropping e and
adding -oic
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Esters
 Carboxylic acid reacting with an alcohol to
form an ester.
 Sweet fruity smell (bananas, oranges)
Acetylsalicylic acid
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Amines
 Have one carbon nitrogen bond. N-C
 1° one N-C bond
 2° two N-C bond
 3° three N-C bond
 Common names are often used rather than IUPAC
names.
 Fish like odor
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methyl amine
ethyl amine
propyl amine
cyclobutyl amine
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Homework
 Pg 1102-1103
 #’s: 41, 47, 49, 50
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