6.1.3: Carboxylic acids and esters Flashcards
What is the functional group of a carboxylic acid?
-COOH (C=O and C-OH)
How do you name carboxylic acids?
-oic acid
Are carboxylic acids soluble in water? Why? What
influences their solubility
Yes. Acid group can form hydrogen bonds with water molecules
What are the intermolecular forces in carboxylic
acids?
Hydrogen bonds in solid state - very strong.
What are esters (what are they formed from)?
Functional group, general formula?
Formed from carboxylic acids and alcohols.
RCOOR’ (C=O, C-O-C)
Write an equation for the reaction of ethanoic acid with propan-1-ol
CH3COOH + CH3CH2CH2OH → CH3COOCH2CH2CH3 + H2O
How do you name esters?
Start with the alcohol group that has replaced the hydrogen, then acid part e.g. propyl (from alcohol) ethanoate (from carboxylic acid)
What characteristic physical properties do esters
have?
Volatile, pleasant fruity smells e.g. apple, pear
drops
What are some uses of esters?
Flavourings, perfumes (both for longer chains), solvents (short chains), plasticisers
How could you distinguish carboxylic acids from other -OH containing compounds?
Add NaHCO3, acids will produce sodium salt, water and carbon dioxide.
Write an equation for the reaction of ethanoic acid
with NaOH.
CH3COOH + NaOH → H2O + CH3COO-Na+
Write an equation for the reaction of ethanoic acid
with Na2CO3
2CH3COOH + Na2CO3 → 2CH3COO-Na+ + H2O + CO2
Write an equation for the reaction of ethanoic acid with
calcium oxide
2CH3COOH + CaO → (CH3COO)2Ca + H2O
What catalyst is needed for the formation of esters
from alcohols and carboxylic acids?
Concentrated strong acid e.g. H2SO4
What catalyst is needed for the hydrolysis of esters?
Dilute strong acid e.g. H2SO4
What is an alternative method of hydrolysis?
Base hydrolysis
What are the advantages of base hydrolysis?
Reaction goes to completion due to neutralisation
by base - more product in the mixture than acid
catalysed hydrolysis.
What are carboxylic acid derivatives?
Molecules that have the acyl group as part of their structure, formed from carboxylic acids
Name two acid derivatives and give their functional
groups.
Acyl chlorides: RCOCl
Acid anhydrides: RCOOCR / (RCO)2O
How do you form an acyl chloride?
React a carboxylic acids with SOCl2
If the nucleophile is ammonia for the acylation of acyl
chlorides or acid anhydrides, what are the products
of the reaction?
an amide
Write an equation for the reaction of ethanoyl
chloride and ammonia
CH3COCl + 2NH3 → CH3CONH2 + NH4Cl
If the nucleophile is a primary amine, what are the
products of the acylation of acyl chlorides or acid
anhydrides?
N-substituted amide
Write an equation for the reaction of ethanoyl
chloride and methylamine
CH3COCl + CH3NH2 → CH3CONHCH3 + CH3NH3Cl
If the nucleophile is an alcohol, what are the
products of the acylation of acyl chlorides or acid
anhydrides?
an ester
Write an equation for the reaction of ethanoyl
chloride and ethanol
CH3COCl + CH3CH2OH → CH3COOCH2CH3 + HCl
If the nucleophile is water, what are the products of
the acylation of acyl chlorides or acid anhydrides?
Carboxylic acid (hydrolysis produces an ester linkage)
What is the name of this reaction (the acylation of acyl chlorides/acid anhydrides with water as a nucleophile)?
hydrolysis
Write an equation for the reaction of ethanoyl
chloride and water.
CH3COCl + H2O → CH3COOH + HCl
