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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 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 H propane butane pentane propane C3H8 butane C4H10 pentane C5H12 H H H C C C H H H 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 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.