Carboxylic Acids + Derivatives Flashcards
What are Carboxylic Acids?
Compounds with the Carboxyl (-COOH) functional group which has a carboxyl group (C=O) and a Hydroxyl Group (O-H)
How do you name Carboxylic Acids?
Find the longest carbon chain then adding ‘-oic acid’ on the end. Carboxyl group is always Carbon 1. The carboxyl group will always be at the end
Carboxylic Acids are weak acids. What does this mean?
They dissociate partially to form a H+ ion and a carboxylate ion and equilibrium lies to the left as it dissociates poorly
When they react with Carbonates (CO3 2-), What is formed?
Salt, Carbon Dioxide and water
Write the equation when ethanoic acid reacts with sodium carbonate?
2CH3COOH (Aq) + Na2CO3(s) –> 2CH3COONa + H2O + CO2
Write the equation when ethanoic acid reacts with sodium hydrogen carbonate?
CH3COOH + NaHCO3 –> CH3COONa + H2O + CO2
What are the 2 ways esters can be formed?
- Reacting alcohols with carboxylic acids w/ sulphuric acid catalyst
- Reacting alcohols with acid anhydrides
How are esters named?
Named in 2 sections, first bit is from the alcohol (alkyl) and the second bit is from the carboxylic acid (oate)
Give some uses of Esters?
- Perfumes + food flavourings
- Solvents
- Plasticisers
Why are Esters good solvents?
Esters are polar molecules so other polar compounds will dissolve readily in esters. Also have low boiling points and evaporate easily. This makes them valuable in making glues
Why are Esters used as plasticisers?
Used to make plastics more flexible during polymerisation. They can leach out of the plastic over time and the plastic becomes brittle
Why are Esters used as perfumes + food flavourings?
Some esters have sweet smells such as pear drops.
Explain the process of Ester Hydrolysis
Esters can be hydrolysed (splitting using water) however it can be sped up using acid (acid hydrolysis) and a base hydrolysis
Explain the process of Acid Hydrolysis
Use dilute acid to split ester into a carboxylic acid and an alcohol. We can use sulphuric or hydrochloric acid and is conducted under reflux
What happens to equilibrium if more water is added?
Shifts right and more product is produced
Explain the process of Base Hydrolysis
Use dilute base to split ester into a carboxylate ion and an alcohol. We can use sodium hydroxide and is conducted under reflux.
What happends when u react glycerol (alcohol) and fatty acids (carboxylic acid)?
It produces an ester which makes fats and oil
What is an oil?
An ester
Why do Vegetable oils have lower melting points and are liquid at room temperature?
They have unsaturated hydrocarbon chains that aren’t straight which means the chains cant pack together closely and hence they have lower van der waals forces
What type of molecule is fat?
An ester
Why do Animal Fats have higher melting points and are solids at room temperature?
They have saturated hydrocarbon chains that are straight and more uniform than oils which means the chains can pack together closer hence have much higher van der waal forces
How do you make soap?
Hydrolyse animal fats or vegetable oils by heating with sodium hydroxide.
How do you make bio diesels?
Vegetable oils can be converted into biodiesel by reactin oils with methanol and a potassium hydroxide as a catalyst
What is Biodiesel?
Mixture of fatty acids made from methyl esters and can be made from rapeseed oil
