Reactions of esters

Question 1

What is the general formula of esters?What are they?

Answer 1

• derivatives of carboxulic acids
• the hydrogen from the -OH group is replaced by an alkyl or aryl grou
• general formula is RCOOR’
• called acid derivatives

Question 2

How are esters formed?

Answer 2

• heating a carboxylci azcid with an alcohol in the presence of a strong acid catalyst (under reflux)
  
  • conc sulfuric acid commonly used
• reversible and forms a equilibrium mixture
• condensation reaction

Question 3

What other reactions do esters undergo? why do they do this?

Answer 3

• hydrolysis
• the carbonyl carbonatom of the an ester has a δ+ charge
• the reactants are water
• H+ catalyst
• carboxylic acid and alcohol produced

Question 4

Why do these reaction not go to completion?

Answer 4

• produces an equilibrium mixture containing the ester, water, acid and alcohol
• the acid is a catalyst an only affects the rate at which equilibrium is reached

Question 5

How are esters hydrolysed?

Answer 5

• room temp
• strong acid catalyst
  *

Question 6

How can hydrolysis be completed?

Answer 6

can also be catalysed by bases

removes the acid from the reaction mixture so an equilibrium is not established and the reaction goes to completion, so there is more products in the mixture

results in sodium ethanoate and water being produced

ester + water → carboxylic acid + alcohol –(NaOH)→ sodium (e)thanoate + water

Question 7

Draw the mechanism for base hydrolysis

Answer 7