6.1 Aromatic Compounds, Carbonyls And Acids

-a benzene ring that has undergone a substitution reaction

-where a group or atom is exchanged for another group or atom in a chemical reaction

—esters have the functional group -COO -they are carboxylic acid derivatives where the H from the acid has been replaced with an alkyl chain

-named after the alcohol and carboxylic acid from which they are formed -the first part of the name comes from the alkyl chain with a carbon atom bonded to only one oxygen atom -the second part comes from the alkyl chain containing the C=O carbon atom -it is followed by the suffix -oate

-methyl ethanoate

-the chemical reaction used to make an ester

-to prepare a small ester- alcohol and a carboxylic acid are heated gently in the presence of a sulfuric acid (H2SO4) catalyst,this is a reversible reaction and has a slow rate of reaction- separated by distillation as the ester is volatile, distillation needs to be quick to prevent reverse reaction from occurring -to prepare larger esters-alcohol and carboxylic acid with sulfuric acid catalyst heated under reflux until equilibrium has been established-the ester can be separated using fractional distillation ->this method of preparation of an ester is not suitable for phenol or its derivatives as the rate of reaction is too slow

-sweet smelling compounds used in food flavourings and perfumes -low boiling points -good solvents for polar molecule

-an acid derivative -more reactive than a similar carboxylic acid -made by the removal of a water molecule from two carboxylic acid molecules

-without water

-acid anhydrides will react with alcohols including phenols and its derivatives to make an ester -it is an addition-elimination mechanism -not reversible -therefore has a higher yield than using carboxylic acid -slow rate of reaction that can be increased by gently warming reaction mixture

-a chemical reaction where water causes the breaking of bonds. In a decomposition reaction

-hydrolysis -esters can undergo hydrolysis to form an alcohol

-When esters are refluxed with a catalyst of hot aqueous acids, such as dilute sulfuric acid or dilute hydrochloric acid, the ester will decompose reversibly into an alcohol and a carboxylic acid.

-Alkaline chemicals are bases that can dissolve in water: When an ester is refluxed with a hot aqueous alkali, such as potassium hydroxide or sodium hydroxide, it will decompose into an alcohol and a carboxylate salt. This reaction is not reversible. Alkaline hydrolysis of esters is used to make soaps, therefore it is also called saponification

A chemical that will react with an acid

-COOH

-remove the e from the end of the name of the alkane that has the same number of carbons in its longest carbon chain -add the suffix -anoic acid E.g-a carboxylic acid containing 4 carbon atoms would be called butanoic acid

• by the oxidation of primary alcohols or aldehydes under reflux -acidified potassium dichromate (VI) used as the oxidising agent

-the -COOH functional group allows carboxylic acid molecules to form hydrogen bonds between each other -they can also form hydrogen bonds with water meaning they are soluble in water

-as chain length increases their solubility decreases -as CH2 groups do not form hydrogen bonds with water as they are not polar -so as more of the molecule becomes non-polar solubility will decrease