Download Ch 22: Organic Chemistry

Ch 22: Organic Chemistry
Section 1: Organic Compounds
• Organic Compounds: covalently bonded
compounds containing carbon, excluding
carbonates and oxides.
• Carbon is unique in that its electronic
structure allows it:
1. to bind to itself to form chains and rings
2. to bind covalently to other elements
3. to bind to itself and other elements in
different arrangements.
• Catenation: the covalent bonding of an element to
itself to form chains or rings.
– Can be linked by single, double, or triple covalent
bonds.
• Hydrocarbons: composed of only carbon and
hydrogen; they are the simplest organic
compounds.
– Other organic compounds have hydrocarbon backbones
with elements like O, N, S, and the halogens attached.
• Isomers: compounds that have the same
molecular formula but different structures.
Structural Formulas
• Structural Formula: indicates the number and
types of atoms present in a molecule and
shows the bonding arrangement of the atoms.
– A condensed structural formula is when the bond
between Carbon and Hydrogen is not shown.
• Butane can also be CH3—CH2—CH2—CH3
Geometric Isomers
• Isomers in which the order of atom bonding is
the same but the arrangement of atoms in
space is different.
• Cis: on the same side.
• Trans: on opposite sides.
Structural Isomers
• Also called “constitutional isomers”, are isomers
in which the atoms are bonded together in
different orders.
– Ex: Both are C4H10
• Structural Isomers can have different physical or
chemical properties.
– Ex: Different melting points, boiling points, and density.
Section 2: Hydrocarbons
• Remember, these contain only Carbon and
Hydrogen.
• Hydrocarbons are grouped by the type of
bonding between the carbon atoms.
• Saturated Hydrocarbons are when each
carbon atom in the molecule forms four single
covalent bonds with other atoms.
Alkanes
• Alkanes: hydrocarbons with only single bonds.
• Formula for finding molecular formula for
alkanes: CnH2n+2
• Examples: Find the molecular formula for the
following n values.
– n=5
– n=12
– n=30
– C5H12
– C12H26
– C30H62
Alkanes Cont…
• Only Alkanes with four or more carbon atoms
have structural isomers because they can be
straight or branched.
• The number of structural isomers increases
greatly as the number of carbon atoms in
alkanes increases.
Systematic Naming of Alkanes
Unbranched-Chain Alkane Nomenclature
• Find the prefix that corresponds to the number
of carbon atoms in the chain of the hydrocarbon.
• Then add the suffix –ane to the prefix.
CH3—CH2—CH2—CH2—CH2—CH2—CH3
1
2
3
4
5
6
7
7 Carbons is hept- and add –ane to make heptane.
# of Carbon
Atoms
1
2
3
4
5
Prefix
# of Carbon Prefix
Atoms
Meth6
HexEth7
HeptProp8
OctBut9
NonPent10
Dec-
Branched-Chain Alkane Nomenclature
• Alkyl Groups are groups of atoms that are
formed when one hydrogen atom is removed
from an alkane molecule.
• Alkyl groups are named by replacing the suffix
–ane with –yl.
Alkyl Group
-CH3
Name
Methyl
-CH2—CH3
Ethyl
-CH2—CH2—CH3
Propyl
-CH2—CH2—CH2—CH3
Butyl
-CH2—CH2—CH2—CH2—CH3
Pentyl
Alkane Nomenclature
1. Name the parent hydrocarbon: find the
longest continuous chain of carbons that
have straight-chain branches.
“Prefix for number of carbons” + “-ane”
2. Add the names of the alkyl groups: add
them in alphabetical order and if there is
more than one of the same group present,
attach the appropriate numerical prefix to
the name.
3. Number the carbon atoms in the parent
hydrocarbon: Number them carbon atoms in the
chain to give the lowest numbers possible in the
name. If there are two equal lowest positions
with two different alkyl groups, give the lowest
number to the alkyl group that comes first
alphabetically, before prefixes are added.
4. Insert Position Numbers: put position numbers
of each alkyl group in front of the name of that
group. We do not use the number 1.
5. Punctuate the name: Use hyphens to separate
the position numbers from the names. If there is
more than one number if front of a name, use
commas to separate the numbers.
Examples:
Name the following simple branched-chain alkanes:
1. CH3—CH—CH2—CH—CH—CH3
|
|
|
CH3
CH3 CH3
2. CH3—CH—CH2—CH3
|
CH3
Drawing Alkanes
1. Draw the hydrocarbon chain: Looking at the
prefix, determine how many carbons in the
parent chain. Leave room to add in hydrogens.
2. Add Alkyl Groups: Using the numbers in the
name, determine the locations of any alkyl
groups.
3. Correct Alkyl Groups: Using the prefixes, make
sure the alkyl groups are correct using the alkyl
name. ex. Methyl is CH3 , Ethyl is CH2—CH3
Examples
Draw the condensed structural formula for each
of the following:
1. 2,4-dimethylpentane
2. 4-ethyl-3-methylheptane
3. methylpropane
Cycloalkanes
• Cycloalkanes are alkanes in which the carbon
atoms are arranged in a ring, or cyclic structure.
• Structural Formula for Cyclopentane.
• Formula for finding molecular formula for
cycloalkanes: CnH2n
Homework
• Ch 22.1 pg 714 #1-3
and
• Ch 22.2 pg 741 #15-17
Unsaturated Hydrocarbons
• Unsaturated Hydrocarbons: are hydrocarbons
in which not all carbon atoms have four single
covalent bonds.
• They have one or more double bonds or triple
bonds.
• Carbon atoms easily form double and triple
bonds to other carbons atoms, so multiple
bonds between carbon atoms are common in
organic compounds.
Alkenes
• Alkenes: hydrocarbons that contain double
covalent bonds
• Formula for finding molecular formula for
noncyclic alkenes with one double bond: CnH2n
• Because alkenes have a double bond, they can
have geometric isomers.
Systematic Naming of Alkenes
• Rules are similar to those for naming an alkane.
• The parent hydrocarbon is the longest
continuous chain of carbon atoms that contains
the double bond.
• The carbon atoms are numbered so that the first
carbon atom in the double bond has the lowest
number.
• If there is more than one double bond, the suffix
is changed to indicate the number of double
bonds. Ex: 2 = -adiene 3 = atriene
Alkene Nomenclature
1. Name the parent hydrocarbon: find the
longest continuous chain of carbons that
contains the double bond(s).
“Prefix for number of carbons” + “-ene”
If more than one double bond, modify the suffix.
2. Add the names of the alkyl groups: add
them in alphabetical order and if there is
more than one of the same group present,
attach the appropriate numerical prefix to
the name.
3. Number the carbon atoms in the parent
hydrocarbon: Number them carbon atoms in the
chain so that the first carbon atom in the double
bond nearest the end of the chain has the lowest
number. If numbering from both ends gives the
same numbers, then number from the end nearest
the first alkyl group.
4. Insert Position Numbers: place double-bond
position numbers before the name of the parent
hydrocarbon and the alkyl group position numbers
before the name of the corresponding alkyl group.
5. Punctuate the name: Use hyphens to separate the
position numbers from the names. If there is more
than one number if front of a name, use commas to
separate the numbers.
Examples:
Name the following alkenes:
CH3
|
1. CH3—CH—C=CH2
|
CH2—CH3
2. CH3—CH2—CH2—CH=CH—CH3
Alkynes
• Alkynes: hydrocarbons that contain triple
covalent bonds
• Formula for finding molecular formula for
noncyclic alkanes with one triple bond: CnH2n-2
Systematic Naming of Alkynes
• Rules are similar to those for naming an alkene.
• If there is more than one triple bond, the suffix is
changed to indicate the number of triple bonds.
Ex: 2 = -adiyne 3 = atriyne
Alkyne Nomenclature
1. Name the parent hydrocarbon: find the
longest continuous chain of carbons that
contains the triple bond(s).
“Prefix for number of carbons” + “-yne”
If more than one triple bond, modify the suffix.
2. Add the names of the alkyl groups: add
them in alphabetical order and if there is
more than one of the same group present,
attach the appropriate numerical prefix to
the name.
3. Number the carbon atoms in the parent
hydrocarbon: Number them carbon atoms in the
chain so that the first carbon atom in the triple bond
nearest the end of the chain has the lowest number.
If numbering from both ends gives the same
numbers, then number from the end nearest the
first alkyl group.
4. Insert Position Numbers: place triple-bond position
numbers before the name of the parent
hydrocarbon and the alkyl group position numbers
before the name of the corresponding alkyl group.
5. Punctuate the name: Use hyphens to separate the
position numbers from the names. If there is more
than one number if front of a name, use commas to
separate the numbers.
Examples:
Name the following alkynes:
1. CH≡C—CH—CH3
|
CH3
2. CH3—CH2—CH2—C≡CH
Aromatic Hydrocarbons
• Aromatic Hydrocarbons: have six-membered
carbon rings and delocalized electrons.
• Benzene: is the primary aromatic hydrocarbon.
C6H6 It is a six carbon atom ring with three double
bonds.
Section 3: Functional Groups
• Functional Group: is an atom or group of
atoms that is responsible for the specific
properties of an organic compound.
• Compounds that contain the same functional
group can be classified together because they
will undergo the same types of chemical
reactions.
Classes of Organic Compounds
• Alcohols: are organic compounds that contain
one or more hydroxyl groups.
– Functional Group: —OH
• Alkyl Halides: are organic compounds in
which one or more halogen atoms—fluorine,
chlorine, bromine, or iodine—are substituted
for one or more hydrogen atoms.
– Functional Group: —X (X= F, Cl, Br, or I)
• Ether: are organic compounds in which two
hydrocarbon groups are bonded to the same
atom of oxygen.
– Functional Group: —O—
• Aldehydes: are organic compounds in which
the carbonyl group is attached to a carbon
atom at the end of a carbon-atom chain.
O
||
– Functional Group: —C—H
• Ketone: are organic compounds in which the
carbonyl group is attached to carbon atoms
within the chain.
O
||
– Functional Group: —C—
• Amine: are organic compounds that can be
considered to be derivatives of ammonia,
NH3.
– Functional Group: —N—
|
• Carboxylic Acids: are organic compounds that
contain the carboxyl functional group.
O
||
– Functional Group: —C—OH
• Ester: are organic compounds that have
carboxylic acid groups in which the hydrogen
of the hydroxyl group has been replaced by an
alkyl group.
O
||
– Functional Group: —C—O—
Homework
• Ch 22.2 pg 729 #5 and pg 742 #19-20
and
• Ch 22.3 pg 734 #1