Introduction to Naming Of Hydrocarbons - DOC

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					                                           Cycloalkanes
     Cycloalkanes have one or more rings of carbon atoms. The simplest examples of this
     class consist of a single, unsubstituted carbon ring, and these form a homologous series
     similar to the unbranched alkanes. The IUPAC names of the first five members of this
     series are given in the following table. The last (yellow shaded) column gives the general
     formula for a cycloalkane of any size. If a simple unbranched alkane is converted to a
     cycloalkane two hydrogen atoms, one from each end of the chain, must be lost. Hence the
     general formula for a cycloalkane composed of n carbons is CnH2n.


                              Examples of Simple Cycloalkanes

  Name        Cyclopropane Cyclobutane         Cyclopentane     Cyclohexane     Cycloheptane     Cycloalkane

Molecular         C3H6             C4H8            C5H10           C6H12            C7H14              CnH2n
Formula
Structural                                                                                             (CH2)n
Formula



 Line
Formula




     IUPAC Rules for Cycloalkane Nomenclature
          1. For a monosubstituted cycloalkane the ring supplies the root name ( table above)
             and the sustituent group is named as usual. A location number is unnecessary.
          2. If an alkyl sustituent is large and/or complex, the ring may be named as a
             substituent group on an alkane.
          3. If two different sustituents are present on the ring, they are listed in alphabetical
             order, and the first cited susbtituent is assigned to carbon #1. The numbering of
             the ring carbons then continues in a direction (clockwise or counter-clockwise)
             that affords the second substituent the lower possible location number.
          4. If several substituents are present on the ring, they are listed in alphabetical order.
             Location number are aasigned to the substituents so that one of them is at carbon
             #1 and the other location have the lowest possible numbers, counting in either
             clockwise or counter-clockwise direction.
          5. The name is assembled, listeing in alphabetical order and giving each group ( if
             there are two or more) a location number. The prefixes di, tri, tetra etc. used to
             designte several groups of the same kind, are not considered when alphabetizing.
                      DRAWING STRUCTURAL FORMULA
Draw the structural formula for the following:

   a)   3-chloro-1, 1-dimethylcyclohexane
   b)   4-ethyl-1, 1,3,3-tetramethylcyclohexane
   c)   3-isobutyl-1,1-dipropylcyclobutane
   d)   1-chlro-1-cyclobutyl-4,4-diethylcycloheptane

                                       Alkenes
Alkenes are the unsaturated hydrocarbons that have carbon-carbon double bond. The
general formula for alkenes with only one double bond in the molecule is CnH2n where n
is the number of carbon atoms in the molecule.


IUPAC Rules For Alkenes

   1. Determine the longest continuous chain of carbons that have the double bond
      between two of its carbons. By "longest continuous chain" is meant to be able to
      trace through the carbons without raising the tracer (or finger) off the surface. The
      chain does not necessarily have to be straight.
   2. Number the carbons in the chain so that the double bond would be between the
      carbons with the lowest designated number. This means that you have to decide
      whether to number beginning on the right end or left end of the chain. If it makes
      no difference to the double bond then shift attention to the branched groups.
   3. Identify the various branching groups attached to this continuous chain of carbons
      by name
   4. Name the branched groups in alphabetical order attaching (hyphenating) the
      carbon number it is attached to along the continuous chain of carbons to the front
      of the branch name. If more than one of the same kind of branched group is
      attached to the chain, identify the number carbon each group is attached to as a
      series of numbers separated by commas between each number then a hyphen and
      finally use a greek prefix attached to the branch name.
   5. Attach a numerical prefix indicating the lowest carbon number the double bond is
      between onto the normal alkane name
   6. Drop the "ane" ending and add the "ene" ending associated with the Alkene
      family

Here is an example:

Identify the IUPAC name for the following:

CH2=CH-CH-CH-CH3
       | |
       CH3Br
   1. Identify the longest continuous chain of carbons with the double bond between
      two of them

       Here we have five carbons

   2. Number the carbon chain so the double bond is between the lowest numbered
      carbons

       Numbering from left to right would place the double bond between carbon #1 and
       carbon #2.

   3. Identify and locate all branched groups ,alphabetically, attaching a prefixed
      number equal to the carbon number the branch is attached to.

              Here we have a methyl group attached to the #3 carbon and a halogen
       attached to the #4 carbon. Halogens are named as branches using the following:

-F Fluoro             -Cl Chloro                -Br Bromo          -I Iodo

               So we would have 4-Bromo-3-methyl

Markovnikov's Rule
This is an empirical rule based on Markovnikov's experimental observations which states
that :

         "when an unsymmetrical alkene reacts with a hydrogen halide to give
         an alkyl halide, the hydrogen adds to the carbon of the alkene that has
         the greater number of hydrogen substituents, and the halogen to the
         carbon of the alkene with the fewer number of hydrogen substituents"

This is illustrated by the following example:




Look at the position of the H and the Br in relation to the statement of Markovnikovs
rule given above.

                             Model Building of Alkenes
Objective:
Using the model building kit construct models of variety of alkenes.

Brief Overview:
In this lab, we will use a kit to model the 3D structure of a number of alkenes. After
building the models, you will draw them on paper in a manner intended to represent the
3D appearance.

Safety
The parts of the kits are not toys. Use them only as instructed and only for the purposes
of the lab.

Equipment List

Molecular model kit which contains white and coloured Styrofoam balls and straws. A
sheet containing the picture of the alkenes

Procedure

Alkene is the category name for a set of compounds which contain carbon and hydrogen and
double bond and the rest single bonds. An alkene has the general formula of C nH2n. Build
the following alkenes:

8. ethene (also called ethylene), C2H4
9. propene (also called propylene), C3H6
10. butene (also called butylene), C4H8

Special Note: Butene can have the double bond in two different locations. For your
answer, please use only the structure where the double bond is between the first and
second carbons.

Clean-up Steps
    Unconnect all bonds from the atom models and replace in the box. Inspect around
      your table top and on the floor for lost atoms or bonds.
    With any remaining time in the class period,


                            NAMEING OF ALKENES
                                                       Name:______________________
                                                            Marks: _____________/21

   1. Draw the structure for the following compounds:

   a)   6-methyl-3-heptene
   b)   3,4-dichlorocyclopentene
   c)   2-chloro-4-methyl-2,4-hexadiene
   d)   1-allyl-3-vinylcyclobutane
   e)   3,3,6,6,-tetramethyl-1,4-cyclohexadiene
   f)   4-chloro-1-phenyl-1-pentene
g) 6,6-dimethyl-5-methylene-1,3-cycloheptadiene
h) 2-methyl-3-vinyl-1,4-pentadiene
i) 1-allyl-3,3-dimethyl-2-vinylcyclohexene

2. In the box following each question enter a letter designating one of the
   formulas (A to H).

j)   2,4-dimethyl-1,3-cyclopentadiene ____________
k)   3-chloro-3-methylcyclohexene. ______________
l)   3,3,6,6-tetramethyl-1,4-cyclohexadiene.________
m)   3-bromo-1,1-dimethylcyclopentane.___________
n)   1,1-dibromo-2-isopropylcyclopentane _________
o)   1-chloro-3-cyclopentylbutane.________________
p)   1,1,3-trimethylcyclobutane.__________________
q)   1-isopropyl-2,2-dibromocyclopentane__________
r)   2-cyclohexenylmethyl chloride_______________
s)   1,3,3-trimethylcyclobutane__________________
t)   1,3-dimethyl-1,3-cyclopentadiene____________
u)   Cyclobutylcyclohexane_____________________

				
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