Transcript Organic Chemistry

Organic Chemistry
CARBON RULES OK
SCH3U/4U/4C
Mr. Bauernschmitt
General Panet HS
Why Carbon ?
• Group IV
• 4 stable covalent
bonds
• Readily forms long
chain structures
such as those in
fats and oil.
make ethane
H
x
x
H C xH
x
H
Alkanes from Petroleum
methane
ethane
methane CH4
ethane C2H6
H
H
C
H
H
H
H
propane
H
H
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
hexane C H
hexane
6
14
H
H
C
C
H
H
H
H
butane
propane C3H8
H
H
H
H
C
C
C
H
H
H
pentane
butane C4H10
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
octane C H
octane
8
18
H
H
pentane C5H12
H
H
H
H
H
H
H
C
C
C
C C
H
H
H
H
H
H
H
H
H
H
H
H
H
H H
C
C
C
C
C
C
C C
H
H
H
H
H
H
H
C
C
H H
H
decane C H
decane
10
H
22
Used as fuels. Long chains have higher boiling
points, short chains are only gases at room
temperature. “Saturated”
make butane (rotating bonds)
H
Structures and Formulae
• Chemical (Molecular) formula
• Structural formulae
• Abbreviated structural formula
• Structural Isomers, e.g. C6H14
Functional Groups
•Hydrocarbons are
fairly dull, they burn
and that’s about it….
Examples…
•Make them more
interesting by altering
the electronic
structure and content
Alcohols
•Use double bonds or
add atoms such as O,
N or Cl
Amines
C=C double bonds
Carboxylic Acids
Esters
Amides
Haloalkanes
Functional Groups
In the models we are using we have some
standard atom colours to help us identify them…
C=C bonds in Alkenes
Double bonds are not free to
rotate.
H
But they are reactive
H
Chemical feedstock
Cracking! page 187
make one
Added value…….
H
C
C
H
ETHENE
Addition Reactions
Double bonds are very reactive.
Hydrogen (H2) can be added in.
Other things such as Bromine (Br2) can also be
added.
Alcohols
Add water – get an alcohol
ETHANOL
CH3CH2OH
H
ETHANE 1,2 DIOL
HOCH2CH2OH
•New naming
system is
descriptive
•? Other names?
Functions?
HO
H
H
C
C
H
H
H
H
C
C
H
H
OH
OH
Carboxylic Acids
By further oxidising alcohols we can make organic
acids .
ethanoic acid
CH3COOH
old name for ethanoic acid?
What about methanoic acid?
Condensation reactions
• Lets do it
• Make a model of ethanol and a model of
ethanoic acid
THE reaction for producing the
biopolymers we eat and are made of!
Esters
Ethyl ethanoate
CH3COOCH2CH3
What is this ester used for?
Esters are ‘linking’ groups.
Small esters all have interesting smells.
..........Just add water
Just add water
Hydrolysis
the reverse of condensation
The basis of digestion
Amines
dimethylamine, CH3NHCH3
Amines contain nitrogen atoms. They are derived from
ammonia, NH3.
Another important condensation reaction:
Like alcohols, amine groups will react with ethanoic
acid, to produce......
Amides
Amides are ‘linking’ groups. They exist in lots of forms
and have lots of uses. Proteins are made from these
amide linkages. More of this later..
N-ethylethanamide
CH3CONHCH2CH3
Functional Groups
Examples…
C=C double bonds
Alcohols
Carboxylic Acids
Esters
Amines
Amides
Haloalkanes
Getting familiar
Turn over your notes –
how many functional groups can you
remember between you?
Names only required!
Addition Polymers
Adding many ethene molecules together makes a
polymer…
H
H
C
C
C
+
H
H
H
H
C
H
C
+
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
monomer
repeating unit
C
The real plastics have very
long carbon chains >500
ethene units per molecule
Polyesters and Polyamides
Using ‘double ended’ molecules of acids with either
alcohols or amines we can make condensation
polymers.
Polyesters – use ‘ioic acids’
HOOC-CH2-COOH + HO-CH2-CH2-OH
↓
H2O is released in this
condensation reaction.
HOOC-CH2-COO-CH2-CH2-OH + HOH
The free COOH and OH
groups can further
make long chains
react to
Amino acids
The biological answer to condensation polymers.
R
O
H
C
N
C
OH
H
H
OH
CH3
H
N
C
H
H
Alanine
O
CH2
H
C
N
OH
C
H
H
O
CH2
H
C
N
OH
Phenylalanine
C
H
H
O
C
OH
Serine
Write down the condensation reaction* between alanine
and serine, build the model as well.
Why are amino acids so efficient at polymerization ?
Proteins
Proteins are made from long chains of amino acids
joined via peptide bonds. (polypeptides)
The 3D shape of
proteins is vital to
ensure that they
function correctly in
cells.
Intermolecular forces
hydrogen “bonds”
van der Walls forces
ionic interactions
hydrophobic interaction
cis and trans
• cis double bonds have the two
hydrogen atoms on the same side
• trans double bonds have the two
hydrogen atoms on opposite sides
Draw me: a fatty acid that contains 12 carbon atoms.
Counting the carbon of the carboxylic acid group as
carbon 1, there is a cis carbon-carbon double
bond between carbons 5 and 6 of the chain.
You should assume that, unless otherwise stated, all
the carbon atoms are attached to other carbon
atoms by single covalent bonds and there are
sufficient hydrogen atoms to satisfy the valency of
each carbon atom.