Carboxylic Acids & Esters Flashcards
Water Solubility of Carboxylic Acids
The highly polar O-H and C=O bonds allow carboxylic acid molecules to form hydrogen bonds and have permanent dipole-dipole interactions with water molecules.
Describe the reaction of a carboxylic acid with a metal.
State any observations made
RCOOH + Na → RCOONa + H₂
Na dissolves/effervescence
Describe the reaction of a carboxylic acid with an alkali.
State any observations made
RCOOH + NaOH → RCOONa + H₂O
*Alkali dissolves
Describe the reaction of a carboxylic acid with a carbonate/hydrogen carbonate.
State any observations made
2RCOOH + Na₂CO₃ → 2RCOONa + H₂O + CO₂
NaHCO₃ dissolves/effervescence
This is a simple test for the presence of carboxylic acids
Describe the reaction of a carboxylic acid with alcohol.
State any reagents and conditions needed.
carboxylic acid + alcohol ⇌ ester + H₂O
Reflux/conc. H₂SO₄
Reversible so lower yield
Describe the reaction of alcohol with acid anhydride.
State any reagents and conditions needed.
anhydride + alcohol → ester + carboxylic acid
Warm
Better yield as reaction is IRREVERSIBLE
Alkaline-Catalysed Hydrolysis of Esters
RCOOR + NaOH ⇌ RCOONa + ROH
Reflux/NaOH(aq)
Uses of esters
Perfumes and Flavourings
TRIGLYCERIDE
A triester of glycerol (propane-1,2,3-triol) and three fatty acid molecules.
Saturated Fatty Acid
Single bonds only
Solid - high melting points
Unsaturated Fatty Acid
At least one double bond
Oils - low melting points
Cis Isomerism
Same sides
Trans Isomerism
Opposite
Effect of Trans-Fats on health
Raise LDL and lower HDL levels like saturated fats, which increases the risks of coronary heart disease and strokes
HDL - transport cholesterol out of the blood
LDL - deposit lipids onto artery walls and restrict blood flow
