Acids, esters and polyesters Flashcards
What types of intermolecular forces are present in carboxylic acids?
London forces, permanent dipoles and hydrogen bonds
What is the solubility of carboxylic acids in water?
High solubility due to hydrogen bonds
What is the name for a salt formed from a carboxylic acid?
Carboxylate
What is the test for carboxylic acids?
NaCO3
Effervescence as CO2 is released
Carboxylic acid + hydroxide —–>
Carboxylate salt + water
Carboxylic acid + metal —–>
Carboxylate salt + hydrogen
Carboxylic acid + carbonate —–>
Carboxylate salt + water + carbon dioxide
Carboxylic acid + metal oxide —–>
Carboxylate salt + water
What is a carboxylic acid derivative?
A compound which can be hydrolysed to return the parent carboxylic acid.
What are the three carboxylic acid derivatives?
Acyl chlorides
Acid anhydrides
Esters
How is an acyl chloride named?
_____ oyl chloride
Give the equation for the formation of an acyl chloride from a carboxylic acid.
Carboxylic acid + SOCl2 ——> Acyl chloride + SO2 + HCl
Give the equation for the formation of a carboxylic acid from an acyl chloride.
Acyl chloride + H2O ——> Carboxylic acid + HCl
Give 3 methods of preparing esters
alcohol + carboxylic acid
acid anhydride + alcohol
acyl chloride + alcohol
Give the equation and conditions for the formation of an ester from an alcohol and carboxylic acid.
alcohol + carboxylic acid ester + water
reversible reaction
heat under reflux
conc sulphuric acid catalyst
Give the equation and conditions for the formation of an ester from an alcohol and an acid anhydride.
acid anhydride + alcohol —–> ester + carboxylic acid
RTP
Give the equation and conditions for the formation of an ester from an alcohol and an acyl chloride.
acyl chloride + alcohol ——> ester + hydrochloric acid
RTP
Define hydrolysis.
A chemical reaction with water that breaks a compound into two compounds, where H+ and OH- are incorporated into the new molecules.
Give the equation and conditions for the acid hydrolysis of esters.
ester + water alcohol + carboxylic acid
reversible reaction
dilute sulphuric/ hydrochloric acid catalyst
heat under reflux
Give the equation and conditions for the alkaline hydrolysis of esters.
ester + alkali ——–> carboxylate salt + alcohol
RTP
Why does alkaline hydrolysis give a better yield than acid hydroysis?
It is a non-reversible reaction, so all of the reactants get converted into products
How can a carboxylic acid be restored from its carboxylate salt?
By adding a strong acid which donates protons to the carboxylate salt to produce its conjugate base (the carboxylic acid).
Which two functional groups must be present in a monomer to form a polyester?
alcohol
carboxylic acid
Which two combinations of monomers allow polyesters to form?
A hydroxy carboxylic acid
OR
A diol with a dicarboxylic acid
