Transcript Organic Chemistry

Organic Chemistry
Last unit for the year.
What does Organic mean?
• The word Organic –
– in Biology it means any thing that is living or
has lived. The opposite is Non-Organic.
– in Chemistry, an Organic compound is one
containing Carbon atoms. The opposite term
is Inorganic.
Inorganic
• All substances are made up of molecules
which are collections of atoms.
• We have spent the year studying simple
Inorganic molecules containing only a few
atoms.
– For example, a water molecule is composed
of two atoms of Hydrogen and one atom of
Oxygen. We write its formula as H2O.
Carbon
• By far and away the best atom for making
large molecules with is Carbon.
• Carbon can make molecules that have
tens, hundreds, thousands even millions of
atoms!
• The huge number of possible
combinations means that there are more
Carbon compounds than those of all the
other elements put together!
• A single Carbon atom is capable of combining
with up to four other atoms.
• The Carbon atom is one of the few that will
combine with itself.
• This means that Carbon atoms can form chains
and rings onto which other atoms can be
attached.
• This leads to a huge number of different
compounds. All organic chemistry is based upon
unique properties of the carbon atom.
Carbon Atom
• Carbon, C, hybridization to 3 sp3 orbitals,
carbon can now form 4 bonds, may be
single, or in combination of double (sp2) or
triple bonds (sp). Carbon forms very
strong bonds with many non-metal atoms,
H, O, Cl, N.
– Note: silicon and germanium are in the same
family and form 4 bonds, but the bond energy
is low, so weak bonds are formed. This
severely restricts their chemistry.
Hydrocarbons
• Carbon compounds are classified according to
how the Carbon atoms are arranged and what
other groups of atoms are attached.
• The simplest Organic compounds are made up
of only Carbon and Hydrogen atoms only. Even
these run into thousands!
• Compounds of Carbon and Hydrogen only are
called Hydrocarbons.
• Saturated Hydrocarbon - only C-H and single C-C
• Unsaturated Hydrocarbon - one or more multiple
C-C
1. Straight chain: The carbons are bonded to no more
than two other carbons.
2. Branched chain: At least one carbon is bonded to more
than two other carbons. The branches are referred to
as substituent groups.
3. Cyclic: All of the carbons are bonded to two other
carbons. Aromatic compounds are a special class
of cyclic hydrocarbons.
Types of Hydrocarbons
A. alkanes - comprised of all single bonds
CnH2n+2
B. alkenes - comprised of at least one
double bond
CnH2n
C. alkynes - comprised of at least one triple
bond
CnH2n-2
Structural vs Condensed
 Structural formulas
show all the atoms
and bonds in the
molecule.
 Condensed structural
formulas show the
number of hydrogens
around each carbon.
CH3CH3
Alkanes
• Hydrocarbon chains where all the bonds
between carbons are SINGLE bonds
• Name uses the ending –ane
• Examples: Methane, Propane, Butane,
Octane, 2-methylpentane
Prefixes for # of Carbons
1
Meth
6
Hex
2
Eth
7
Hept
3
Prop
8
Oct
4
But
9
Non
5
Pent
10
Dec
Prefix-Parent-SUFFIX
Root
Meth
Eth
Prop
But
Pent
Hex
Hept
Oct
Non
Dec
Number of
Carbons
1
2
3
4
5
6
7
8
9
10
Functional Group
• Alkane
• Alkene
• Alkyne
• Alcohol
• Ketone
• Aldehyde
• Carboxylic acid
• Ester
• Amide
Ending
ane
ene
yne
ol
one
al
oic acid
oate
amide
Summary: IUPAC Rules for Alkane
Nomenclature
1. Find and name the longest continuous carbon chain. This
is called the parent chain. (Examples: methane, propane,
etc.)
2. Number the chain consecutively, starting at the end
nearest an attached group (substituent).
3. Identify and name groups attached to this chain.
(Examples: methyl-, bromo-, etc.)
4. Designate the location of each substituent group with the
number of the carbon parent chain on which the group is
attached. Place a dash between numbers and letters. The
prefixes di-, tri-, etc. are used to indicate multiple identical
substituents. (Example: 3-chloropentane)
5. Assemble the name, listing groups in alphabetical order.
The prefixes di, tri, tetra etc., used to designate several
groups of the same kind, are not considered when
alphabetizing. Place a comma between multiple numbers.
(Example: 2,3-dichloropropane)
Step 1. Find the parent chain.
• Where is the longest continuous chain of
carbons?
Prefixes for # of Carbons
1
Meth
6
Hex
2
Eth
7
Hept
3
Prop
8
Oct
4
But
9
Non
5
Pent
10
Dec
Endings
• Alkanes (all C-C single bonded parent
chain) end in –ane
– Methane CH4
– Ethane C2H6
– Propane C3H8
• Attached carbon groups (substituents) end
in –yl
– Methyl CH3 – Ethyl CH3CH2– Propyl CH3CH2CH2 –
3-ethylpentane
Step 2. Number the parent chain.
• Number the parent chain so that the
attached groups are on the lowest
numbers
Methyl is on carbon #2 of the parent chain
Methyl is on carbon #4 of the parent chain
1
5
1 8
2
4
3
3
4
2
3 6
7 2
8 1
4 5 5 4
6 3
5
1
GREEN is the right
way for this one!
27
1
7
2
6
3
5
4
4
Groups on 2 and 5
Groups on 4, 6, and 7
Groups on 2, 3, and 5
5
3
6
72
1
Groups on 3 and 6
Step 3. Name the attached groups.
• Carbon (alkyl) groups
– Methyl CH3 – Ethyl CH3CH2– Propyl CH3CH2CH2 –
• Halogens
– Fluoro (F-)
– Chloro (Cl-)
– Bromo (Br-)
– Iodo (I-)
Step 4. Designate where the group
is attached to the parent chain.
• Use the numbers of the parent chain from
step 2 to designate the location of the
attached groups to the parent chain.
2-methyl
1
2
3
4
5
Step 5. Alphabetize the groups,
combine like groups, and assemble.
• The prefixes di, tri, tetra
etc., used to designate
several groups of the
same kind
• Prefixes are not
considered when
alphabetizing (Example:
dimethyl = m for
alphabetizing)
• Parent chain goes LAST
1,1,1-trichloro-1fluoromethane
1,1-dichloro-1,1difluoromethane
Name the Alkanes
Name the Alkanes
2,4-dimethylhexane
2,3,4-trimethylhexane
3,3-diethylpentane
3
H3 CH CH CH2 CH CH3
Alkanes
C
CH
CH3
CH
H3
2
3
CH
3
Example:
Name the following compounds:
CH3
CHCH3
CH3 C CH2 CH2Br
CH2CH3
CH3
CH CH3
CH3 CH CH CH2 CH CH3
CH2CH3
CH3 C CH3
CH3
3
H3 CH CH CH2 CH CH3
Alkanes
C
CH
CH3
CH
H3
2
3
CH
3
Example:
Name the following compounds:
CH3
CHCH3
CH3 C CH2 CH2Br
CH2CH3
1-bromo-3-ethyl-3,4-dimethylpentane
CH3
CH CH3
CH3 CH CH CH2 CH CH3
CH2CH3
CH3 C CH3
CH3
2,2,3,6-tetramethyl-4-isopropyloctane
Draw Some Simple Alkanes
• 2-methylpentane
• 3-ethylhexane
• 2,2-dimethylbutane
• 2,3-dimethylbutane
Alkanes
Example: Write the condensed
structure for the following compounds:
3,3-dimethylpentane
1,2-dichloro-3-methylheptane
On packet
• Number 9 – tert-, sec-, n-butyl