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Naming Organic Molecules

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					Naming Organic Molecules
Organic molecules are named using the number
  of carbons they contain, and the functional
  groups that the molecule contains. As carbon
  can form 4 bonds there is a huge number of
  molecules that can be formed.
Organic molecules derive their properties from
  the functional group of that molecule.
The number of carbons is denoted by using
  prefixes, the functional groups are denoted by
  suffixes.
 Prefixes for the carbons in a chain
1.   Meth-          6. Hex-
2.   Eth-           7. Hept-
3.   Prop-          8. Oct-
4.   But-           9. Non-
5.   Pent-          10. Dec-

Prefixes enumerating the number of
            side chains
1. N/A       3. tri-           5. penta-
2. di-       4. tetra-
                  Functional groups
Name              Functional group    Group general   Naming suffix
                                      formula
Branch chain                                          -yl

Alkane            -C-C-               CnH2n+2         -ane

Alkene            -C=C-               CnH2n           -ene

Alkyne            -C=C-               CnH2n-2         -yne

Haloalkane        -X eg. -Cl -Br -I   R-X             Halo- -ane.

Alcohol           -OH                 R-OH            -anol

Carboxylic Acid   -COOH               R-COOH          -anoic acid

Ester             -COO-               R-COO-R’        -yl     -anoate
             Applying names
1. Identify functional group
2. Count the number of Carbons in the longest
   chain
3. Name main chain
4. Count the carbon that the functional group is
   attached to and place this in between the
   prefix and the suffix
5. Identify branch chains
6. Count carbons in branch chain(s)
7. Put the branch chain name in front the main
   chain name
8. Count to which carbon the branch chain is
   attached to (make sure it’s the lowest
   number possible- count from both ends)
9. Put the number of the carbon in front of the
   branch chain name.
10.Where there are multiple branch chains use
   the branch chain prefixes to indicate how
   many there are of that type of chain
11.Number the carbons of the branch chains to
   achieve the lowest possible numbers. All
   carbons must be numbered from the same
   end
12. Assemble your molecule name!
Naming organic molecules - summary
1. Identify functional group
2. Name main chain
  – Number of carbons + functional group + poistion
3. Name branch chain(s)
  – Number of carbons in chains
  – Number of each type of chain
  – Which carbon the chain attaches to
 Naming organic molecules - examples

1. Identify functional          1. Double bond = alkene
   group                        2. Name main chain
2. Name main chain                –   8carbons
   –   Number of carbons
                                  –   -ene
   –   functional group
                                  –   2nd carbon
   –   Position of functional
       group                          – Oct-2-ene
3. Name branch chain(s)         3. Name branch chain(s)
   –   Number of carbons in       –   No branch chain
       chains
   –   Number of each type of
       chain
   –   Which carbon the chain
       attaches to                –   .
 Naming organic molecules - examples

1. Identify functional          1. Carboxyl group on end
   group                           = carboxylic acid
2. Name main chain              2. Name main chain
   –   Number of carbons          –    8 carbons
   –   functional group           –   -anoic acid
   –   Position of functional     –   At end
       group                          – Octanoic acid
3. Name branch chain(s)         3. Name branch chain(s)
   –   Number of carbons in       –   No branch chain
       chains
   –   Number of each type of
       chain
   –   Which carbon the chain
       attaches to                –   .
 Naming organic molecules - examples

1. Identify functional          1. Hydroxyl group - alcohol
   group                        2. Name main chain
2. Name main chain                –    5 carbons
   –   Number of carbons          –   -anol
   –   functional group           –   1st or 5th carbon
   –   Position of functional         – Pentan-1-ol
       group                    3. Name branch chain(s)
3. Name branch chain(s)           –   No branch chain
   –   Number of carbons in
       chains
   –   Number of each type of
       chain
   –   Which carbon the chain     –   .
       attaches to
 Naming organic molecules - examples

1. Identify functional          1. Carboxyl group in the
   group                           middle - ester
2. Name main chain              2. Name main chain =O
   –   Number of carbons           side
   –   functional group           –    5 carbons
   –   Position of functional     –   Double bonded O side
       group                          – Pentanoate
3. Name branch chain(s)         3. Name branch chain(s)
   –   Number of carbons in       – 3 carbons
       chains                     – Singly bonded O side
   –   Number of each type of     – Propyl
       chain
                                – Propyl propanoate
   –   Which carbon the chain
       attaches to
 Naming organic molecules - examples

1. Identify functional          1. Hydroxyl group at
   group                           the end - alcohol
2. Name main chain
   –   Number of carbons
                                2. Name main chain
   –   functional group           – 6 carbons
   –   Position of functional     – OH at the end
       group                        – Hexan-1-ol
3. Name branch chain(s)
   –   Number of carbons in
                                3. Name branch
       chains                      chain(s)
   –   Number of each type of     – 1 carbon
       chain                    – Attached to 4th carbon
   –   Which carbon the chain
       attaches to              – 4-Methyl-hexan-1-ol
               Haloalkanes
• Haloalkanes are alkanes with a halogen
  attached to the chain
• The alkane is named with the halogen and the
  alkane name eg. Bromo-pentane
• The number of the carbon to which the
  halogen is attached used to denote which
  isomer of bromo-pentane it is eg. 3-bromo-
  pentane, 1-bromo-pentane
 Geometric isomers - cis and trans
In alkenes the double bond fixes the position of
   side groups and branch chains relative to the
   functional group (the double bond)
If the groups are on the same side, the molecule
   is prefixed with cis
When the groups are on different sides the
   groups are prefixed with trans

				
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