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Unit 3 Organic Chemistry (PowerPoint)

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					Unit 3
Organic Chemistry
           Chemistry 2202
Introduction
   Organic Chemistry is the study of the
    molecular compounds of carbon.
    eg. CH4     CH3OH   CH3NH2
   Organic compounds exclude oxides
    of carbon and ions containing carbon.
    ie. CO    CO2   KCN CaCO3
      are NOT organic compounds!!
History of Organic Chemistry
 Started when medicine men extracted
  chemicals from plants and animals as
  treatments and cures
 First defined as a branch of modern
  science in the early 1800's by Jon
  Jacob Berzelius
 Berzelius believed in Vitalism -
  organic compounds could only
  originate from living organisms
  through the action of some vital force
 organic compounds originate in living
  or once-living matter
 inorganic compounds come from
  "mineral" or non-living matter
   In 1828, Friedrich Wöhler
    discovered that urea - an organic
    compound - could be made by
    heating ammonium cyanate (an
    inorganic compound).

       NH4OCN(aq)  (NH2)2CO(s)


    inorganic            organic
What’s this?
(NH2) 2CO - (NH2)2CO




              di-urea
 organic chemistry branched into
  disciplines such as polymer
  chemistry, pharmacology,
  bioengineering and petro-chemistry
 98% of all known compounds are
  organic
   The huge number of organic
    compounds is due mainly to the
    ability of carbon atoms to form stable
    chains, branched chains, rings,
    branched rings, multiple rings, and
    multiple bonds (double and triple
    bonds) to itself and to many other
    non-metal atoms.
   Some more Organic notes
Sources of Organic Compounds
 1. Carbonized Organic Matter
 - fossil fuels such as coal, oil, and
     natural gas
 - basis for the petrochemical industry

 2. Living Organisms
 eg: - penicillin from mold
    - ASA from the bark of a willow tree
3. Invention
- antibiotics, aspirin, vanilla flavoring,
  and heart drugs are manufactured
  from organic starting materials
- plastics
Structural Isomers
   Structures that have the same molecular
    formula but different structural formulas
    are called structural isomers
    eg. C4H10

    Practice: Draw all structural isomers
              of C5H12 and C6H14
Structural Isomers
   structural isomers have the same
    chemical formula but have different
    chemical and physical properties.
Classifying Organic Compounds
                 Organic
                Compounds
Hydrocarbons                         Hydrocarbon
                                      Derivatives
                  Aromatic       •    Alcohols
 Aliphatic                       •    Ethers
               (benzene based)
                                 •    Aldehydes
    AlkAnes                      •    Ketones
                                 •    Carboxylic Acids
    AlkEnes                      •    Alkyl Halides
                                 •    Esters
     AlkYnes                     •    Amines
                                 •    Amides
 hydrocarbons consist of carbon
and hydrogen atoms only
  eg. Methane - CH4
 hydrocarbon derivatives have one
  or more hydrogen atoms replaced by
  another nonmetallic atom
  eg. bromomethane - CH3Br
      methanol - CH3OH
 aliphatic hydrocarbons have
  carbon atoms bonded in chains or
  rings with only single, double, or
  triple bonds
 aromatic hydrocarbons contain at
  least one 6 carbon benzene ring
Aliphatic Hydrocarbons

1. Alkanes
   Alkanes are hydrocarbons that have
    only single bonds between carbon
    atoms
   general formula CnH2n+2

    eg. C3H8       C6H14
IUPAC      Prefix   # of carbon
prefixes               atoms
           meth           1
            eth           2
           prop           3
            but           4
           pent           5
           hex            6
           hept           7
            oct           8
           non            9
           dec           10
Complete this methane      CH4
table for the     ethane
first 10 alkanes propane
A series of compounds which differ
 by the same structural unit is called
 a homologous series
 eg. each alkane increases by CH2
 What is the next member of this
 homologous series?
SiO2     Si2O3   Si3O4    _____
Representing Alkanes (4 ways)
1. Structural formulas
  eg. propane

                    H    H   H
                H–C–C–C–H
                    H    H   H
   Hydrogen atoms may be omitted
    from structural formulas
    eg. propane

                  –C–C–C–
2. Condensed Structural Formula


eg. propane
            CH3-CH2-CH3
3. Line Structural Diagrams


eg: propane

 (the endpoint of each segment is a
    carbon atom)
4. Expanded Molecular Formulas

eg. propane
        CH3CH2CH3

    p. 333
Alkyl Groups

   An alkyl group has one less hydrogen
    than an alkane.
 General Formula: CnH2n + 1
 To name an alkyl group, use the
  prefix to indicate the # of carbon
  atoms followed by the suffix –yl
  eg. -C7H15 heptyl
Alkyl Groups

methyl -CH3

ethyl -C2H5 or -CH2CH3

propyl -C3H7 or -CH2CH2CH3
Alkyl Groups
   Branched alkanes are alkanes
    that contain one or more alkyl
    groups
      eg.
Naming Branched Alkanes

      the longest continuous chain of
1. Find
 carbons(parent chain) and name it
 using the alkane name.

2. Number the carbons in the parent
 chain starting from the end closest to
 branching. These numbers will
 indicate the location of alkyl groups.
Naming Branched Alkanes
3.   List the alkyl groups in alphabetical
     order. Use Latin prefixes if an alkyl
     group occurs more than once.
     (di = 2, tri = 3, tetra = 4, etc.)

4.   Use a number to show the location of
     each alkyl group on the parent.
Naming Branched Alkanes

5.   Use commas to separate numbers,
     and hyphens to separate numbers
     and letters.
Naming Branched Alkanes

eg.                             ethyl




          7   6   5   4   3     2    1


                                    methyl
      4-ethyl-3-methylheptane
Naming Branched Alkanes

Practice:
   p. 336 - 339 #’s 5 – 11

     (Answers on p. 375)
 Alkenes and Alkynes
 saturated  hydrocarbons contain
  only single bonds between carbon
  atoms
  eg. alkanes
 saturated hydrocarbons have the
  maximum number of hydrogen
  atoms bonded to carbon atoms
Alkenes and Alkynes
   unsaturated hydrocarbons contain
    double or triple bonds between
    carbon atoms
    eg. alkenes and alkynes
Alkenes and Alkynes
 General   Formulas:
                        At least one
                        double bond
  Alkenes CnH2n



  Alkynes CnH2n - 2
                           At least one
                           triple bond
     Naming Alkenes and Alkynes

1.   Name the longest continuous
     chain that contains the
     double/triple bond.
2.   Use the smallest possible
     number to indicate the position of
     the double or triple bond.
Naming Alkenes and Alkynes
3.   Branches are named using the
     same rules for alkanes.
4.   Number the branches starting at
     the same end used to number
     the multiple bond.
Naming Alkenes and Alkynes
 p. 347 #’s 17 - 19
 p. 354 #’s 28 & 29
Cyclic Hydrocarbons
   Pp. 356 – 358
     questions 30 & 31
3-ethyl-1-methylcyclopentane
1-ethyl-3-methylcyclopentane

                        cyclopentane

                        2
                    1       3




         ethyl                  methyl
             methyl




1,2,3,4-tetramethylcyclohexane
    Aromatic Compounds

 Aromatic hydrocarbons contain at least
  one benzene ring.
 The formula for benzene, C6H6 , was
  determined by Michael Faraday in 1825.
 The structural formula was determined by
  August Kekulé in 1865.
  Aromatic Compounds
Proposed formula:
 Conflicting Evidence
 C=C double bonds are shorter than C-
  C single bonds. X-ray crystallography
  shows that all C-C bonds in benzene
  are the same length.
 Benzene reacts like an alkane, not like
  an alkene.
Modified structure
 Kekulé proposed a resonance
  structure for benzene.
 The resonance structure is an
  average of the electron distributions.
Aromatic Compounds



            or
    Aromatic Compounds
 bonding electrons, once believed to be
  in double bonds, are delocalized and
  shared equally over the 6 carbon atoms
 the bonds in benzene are like “1½”
  bonds – somewhere between single
  and double.
Naming Aromatic Compounds
 an alkyl benzene has one or more H
  atoms replaced by an alkyl group.
 name the alkyl groups, using
  numbers where necessary, followed
  by the word benzene.
Aromatic Compounds




methylbenzene       ethylbenzene



          propylbenzene
Aromatic Compounds
                1,3-dimethylbenzene




                  1,4-dimethylbenzene

1,2-dimethylbenzene
Aromatic Compounds
 ortho- means positions 1 and 2 and is
  represented by "o"
 meta- means positions 1 and 3 and is
  represented by "m"
 para- means positions 1 and 4 and is
  represented by "p"
Aromatic Compounds
                m-dimethylbenzene




                    p-dimethylbenzene

o-dimethylbenzene
Aromatic Compounds
 Benzene is treated as a branch if it is
  not attached to the terminal carbon of
  an alkyl group
 Benzene as a branch is called phenyl
Aromatic Compounds
      CH3

      CH2

      CH2



                CH3 CH CH3

                2-phenylpropane
propylbenzene
Aromatic Compounds




 CH3 CH2 CH2 CH CH CH3
            CH2
            CH3
Aromatic Compounds
                  CH3

                  CH2

                  CH2 CH3

CH3 CH2 CH2 CH CH2 CH CH CH3
Aromatic Compounds
   p. 361 #’s 32 – 35

Hydrocarbons Practice
    pp. 363, 364
         #’s 4 – 9
Test!!
cis and trans isomers (p. 348)
      Properties of aliphatic
         hydrocarbons
 Because they are nonpolar, all
  hydrocarbons are insoluble in water.
 The boiling point of alkanes is somewhat
  higher than alkenes but lower than
  alkynes.
 As the number of atoms in the
  hydrocarbon molecule increases, the
  boiling point increases.
           Reactions
Complete the aliphatic hydrocarbons
worksheet using these references:
a) complete combustion (p. 340)
b) incomplete combustion (p. 340)
c) substitution reaction (p. 344, 362)
d) addition reaction (p. 349)
    Hydrocarbon Derivatives
 hydrocarbon derivative - contains
  other nonmetal atoms such as O, N, or
  halogen atoms.
 9 types

 functional group - the reactive group
  of atoms that gives a family of
  derivatives its distinct properties
    Hydrocarbon Derivatives

   The general formula for a derivative is
          R - functional group
    where R stands for any alkyl group.
 Hydrocarbon Derivatives
eg. ALCOHOLS R-OH
       ethanol  C2H5OH
       propanol C3H7OH

 CARBOXYLIC ACIDS R-COOH
      ethanoic acid  CH3COOH
      propanoic acid C2H5COOH
1. Alcohols
   Have the hydroxyl functional group

    General Formula: R - OH
    Naming Alcohols (p. 387)
   The parent alkane is the longest chain
    that has an -OH group
 Replace the last -e in the alkane name
  with the suffix -ol.
 Add a number to indicate the location of
  the -OH group.
    H
                methanol
H   C   O   H

    H


    H   H

H   C   C   O   H

    H   H           ethanol
              H       H       H

      H       C       C       C   O   H
eg.
              H       H       H

          H

      H   O       H

 H    C   C       C       H

      H   H       H
Properties of Alcohols (p. 389)
 Alcohols have H-bonding which
  makes their mp and bp higher than
  the corresponding alkane.
 Polarity decreases as the # of carbon
  atoms increases
 Long chain alcohols are less soluble
  in water than short chain alcohols.
Reactions of alcohols
Combustion
 R-OH + O2 → CO2 + H2O

eg. Write the equation for the burning
 of butanol.
Reactions of alcohols
Substitution

R-OH + H-X → R-X + H2O

eg. Use structural formulas to show
 the reaction between 2-pentanol and
 HBr.
 Reactions of alcohols
 Elimination (Dehydration)
 eg.
  H H H        H2SO4       H H H
H C C C O H              H C C C H
  H H H                    H
                              + H2O
P. 393 16 a), d), 18 a), b), d) & e)
    (Draw structural formulas for the
             products in #18)
2. Ethers

 Composed   of two alkyl groups
  bonded to an oxygen atom.
 General Formula: R1-O-R2

 Naming ethers: p. 395

   IUPAC name

   Common name
    H       H   H
H   C   O   C   C   H
    H       H   H



    H   H   H       H   H   H   H
H   C   C   C   O   C   C   C   C   H
    H   H   H       H   H   H   H
     H   H        H     H
H    C   C    O   C     C   H
     H   H        H     H


    P. 395, 396 #’s 20 – 23
    Worksheet: Ethers
 3. Aldehydes (p. 402)

 Containa carbonyl functional
 group at the end of a carbon chain.

 General Formula:           O
                      R-C
                            H
Naming:
 Use the alkane name for the
  longest continuous chain.
 Remove the –e and add the suffix
  –al
           H    H  H   H
eg.
      H   C   C   C   C   O

          H   H   H
 4. Ketones (p. 402)

 Contain a carbonyl functional group
 in the ‘middle’ of a carbon chain.
 ie. NOT on carbon #1




                       =O
 General Formula:   R1-C- R2
Naming:
 Use the alkane name for the longest
  continuous chain.
 Replace the –e with the suffix –one

 Use the smallest possible number for
  the position of the C=O group.
    H    H    O    H

H         C        C
    Cp. 403 #’sC - 31
               28         H

    HHandout: Aldehydes
        H          H
             and Ketones

    H   H    H    O       H

H   C   C    C    C       C   H

    H   H    H            H
5. Carboxylic Acids (p. 405)
Contain a carboxyl functional group
    ie. -COOH




                         =O
 General Formula:

                     R1-C- OH
AKA: Organic Acids
     H   H   O

H    C   C   C   OH

     H   H
                        O      H   H   H

                  HO    C      C   C   C   H

                               H   H   H
    Text; p. 406 #’s 32 - 35
6. Alkyl Halides (p. 390, 391)
Contain at least one halogen atom

General Formula: R – X
                (X is F, Cl, Br, or I)
        Br   Br
    H             H

H   C   C    C    C       H

    H   H    Br   H
                              H   Cl   Br   Br   H

                      H       C   C    C    C    C   Br

                              H   Br   H    H    H
    Text; p. 406 #’s 32 - 35
    Text; p. 391 #’s 12 – 15
    Worksheet: Organic # 8
 Elimination - Alcohols
 eg.
  H H H         H2SO4       H H H
H C C C O H               H C C C H
  H H H           Δ         H
                               + H2O
    Elimination – Alkyl Halides
    eg.
      H   H   H                     H   H   H

H     C   C   C   I   + OH- →   H   C   C   C   H

                                    H
      H   H   H

                                    + H2O + I-
    p.393 #’s 18 c) and f)
  7. Esters (pp. 410, 411)
 Form when a carboxylic acid reacts with
 an alcohol
General Formula:      O


                        =
                    R1-C- O-R2
Esterification Reaction:
 carboxylic acid + alcohol → ester + water
Naming:
 - the parent is named by replacing the
– oic acid ending from the acid with – oate
 - the alcohol is identified by using the
 corresponding alkyl group
pp. 411, 412 #’s 36 - 40
  8. Amines (pp. 410, 411)
 Form when a carboxylic acid reacts with
 an alcohol
General Formula: R – NH2
  Cracking & Reforming
‘Cracking‘ is a reaction that break long chain
  hydrocarbons into smaller fragments.
 eg.
  decane + H2 → ethane + octane
Reactions – Organic Compounds

Combustion (p. 340)
Substitution (p. 344)
Esterification (p. 410)
Elimination (p. 390)
  Cracking & Reforming
‘Reforming’ is a reaction that combines smaller
  hydrocarbons to make long chain hydrocarbons

eg.
 ethane + butane → hexane + H2
Review - Derivatives
pp. 400, 401
Omit:     1a), 2c) & d), 3b) & e), 5b),
         8, 10b) & c), 11b) & d)

pp. 419, 420
Omit:     1g), 3d), 4a), 7, 8c), 10

				
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