Organic Chemistry

Organic ChemistryFunctional GroupsFunctional GroupsThe bond, atom, or group of atoms which gives a molecule its specific properties is called its functional group.Eg The functional group of the alkenes is C = C; the functional group of the alkanols (alcohol) is OH.HaloalkanesHaloalkanes contain a halogen atom; F, Cl, I or Br (group 17 elements). These group 17 elements have replaced a hydrogen atom from an alkaneHaloalkanes are not hydrocarbonsThe functional group is X, where X is a halogen.The number of the carbon atom to which the halogen has been bonded must be given when naming haloalkanes, followed by the halogen and then the prefix indicating the number of carbons in the chain.Haloalkanes

The AlkanolsThe Alkanols are carbon chains containing one or more OH group.The OH group is sometimes called the hydroxy group.Alkanols have the ending ol.The first four alkanolsNote that each carbon atom has four bonds (valency 4),each oxygen atom has two bonds (valency 2)and each hydrogen atom has one bond (valency 1).Valency is the combining power of an atom.

Alkanol reactionsMany alkanols can be oxidised (slowly) by atmospheric oxygen and (quickly) by strong laboratory oxidants such as acidified potassium permanganate (KMnO4) or acidified potassium dichromate (K2Cr2O7).The product of such processes is usually a carboxylic acid.Alkanols also undergo combustion reactions in air. They can be used as fuelsNaming of AlkanolsPropanol (C3H7OH) is commonly represented by the molecule propanol which has the structural formula

Another isomer of propanol called propan-2-ol is commonly represented by the structural formula where the single lines between the atoms represent single covalent bonds.

Carboxylic AcidsThe carboxylic acids are another example of a homologous series.These compounds contain the functional group COOH at the end of the chain.When naming a carboxylic acid, add the ending oic acid to the alkyl prefixThese acids have typical acid properties.They are classified as weak acids.Methanoic AcidFormic Acid

Ethanoic AcidAcetic Acidethanol + oxygen ethanoic acid + water.C2H5OH(aq) +O2(g) CH3CO2H(aq) + H2O(l)

Propanoic AcidPropanionic Acid

Butanoic AcidButyric Acid

2-hydroxybenzoic acidsalicylic acid

2-acetoxybenzoic acidacetylsalicylic acid, aspirin

ReviewComplete the revision questions page 183 (29, 30)Reactions of Carboxylic AcidsCarboxylic acids react with alkanols to form esters.Esters are a group of compounds which give the pleasant fruity smell to various fruits.This is called a dehydration or esterification reaction.Concentrated sulfuric acid is used to link the alkanol and carboxylic acid together by removing a water molecule.EstersCH3OH + CH3COOH CH3COOCH3 + H2Omethanol + ethanoic acid methyl ethanoate + water

H2SO4When naming an ester, the alkanol (alkyl) name is given first, followed by the acid part.

The oic ending of the acid is replaced with oate.ReviewWork through the Sample Problem page 184

AminesThe amines have the NH3 functional group and are derived from ammonia, NH3.They are named by adding the suffix -amine to the alkane group to which the NH2 has been addedThey are found in many natural and synthetic drugs. Used in the manufacture of antibiotics, analgesics and tranquilisers.ReviewAlchohol, carboxylic acids, esters on line multiple choice

Complete the revision questions page 185 (31 39)