CARBON RULES OK

SCH3U/4U/4C

Mr. Bauernschmitt

General Panet HS

Organic Chemistry

Why Carbon ?

• Group IV• 4 stable covalent

bonds• Readily forms long

chain structures such as those in fats and oil.

make ethane

C

H

H

H Hx

x

xx

Alkanes from Petroleum

C

H

H

C

H

H

C

H

H

H H H H C

H

H

C

H

H

H C

H

H

H C

H

H

C

H

H

H C

H

H

HC

H

H

C

H

H

C

H

H

H C

H

H

HC

H

H

C

H

H

C

H

H

C

H

H

H C

H

H

C

H

H

C

H

H

C

H

H

H C

H

H

C

H

H

H C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

HC

H

H

C

H

H

C

H

H

H C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

m ethane CH4 ethane C

2H

6 propane C

3H

8 butane C

4H

10 pentane C

5H

12

hexane C6H

14 octane C

8H

18 decane C

10H

22

methane ethane propane butane pentane

hexane octane decane

Used as fuels. Long chains have higher boiling points, short chains are only gases at room temperature. “Saturated” make butane (rotating bonds)

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….

•Make them more interesting by altering the electronic structure and content

•Use double bonds or add atoms such as O, N or Cl

Examples…

C=C double bonds

Alcohols

Carboxylic Acids

Esters

Amines

Amides

Haloalkanes

Functional GroupsIn 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.

But they are reactive

Chemical feedstock

Cracking! page 187

make one

Added value…….

C C

H H

H H

ETHENE

Addition ReactionsDouble bonds are very reactive. Hydrogen (H2) can be added in.

Other things such as Bromine (Br2) can also be added.

AlcoholsAdd water – get an alcohol

C C

HH

H H

O HH

C C

HH

H H

O HH O

ETHANOL

CH3CH2OH

ETHANE 1,2 DIOL

HOCH2CH2OH

•New naming system is descriptive

•? Other names? Functions?

Carboxylic AcidsBy further oxidising alcohols we can make organic acids .

old name for ethanoic acid?

What about methanoic acid?

ethanoic acid CH3COOH

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

What is this ester used for?

Ethyl ethanoate CH3COOCH2CH3

Esters are ‘linking’ groups.

Small esters all have interesting smells.

..........Just add water

Just add water

Hydrolysisthe reverse of condensation

The basis of digestion

Amines

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......

dimethylamine, CH3NHCH3

AmidesAmides 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 GroupsExamples…

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 PolymersAdding many ethene molecules together makes a polymer…

C C

H

H

H

H

C C

H

H

H

H

C C

H

H

H

H

+ +

C C

HH

H

C C

H

H

C C

HH

H

C C

HH

HH H

The real plastics have very long carbon chains >500 ethene units per molecule

monomer repeating unit

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

react to make long chains

Amino acidsThe biological answer to condensation polymers.

O

OH

C CN

H

HH

R

C C

O

OH

N

H

HH

CH3

C C

O

OH

N

H

HH

CH2

C C

O

OH

N

H

HH

CH2

OH

Alanine Phenylalanine Serine

Write down the condensation reaction* between alanine and serine, build the model as well.

Why are amino acids so efficient at polymerization ?

ProteinsProteins 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.