3.09 carboxylic acids and derivatives

• What is the functional group of a carboxylic acid?

  COOH
• What two functional groups make up carboxylic acids?

  C=O O-H
• Where in a carboxylic acid is the carbonyl group?

  On the end (C1)
• Are carboxylic acids soluble in water?

  The first four are. The rest are not.
• Why are 4+ carbon carboxylic acids non soluble in water?

  the hydrocarbon tail increases in size and forces its way between water molecules breaking the hydrogen bonds.

  
  

  new bonds cannot form because the R group is non polar.

  
  

  hydrogen bonds between the molecule and water is what makes something dissolve.
• are carboxylic acids strong acids?

  No, they only partially disocciate into theyre ions when in solution.
• why can only >4 carbonned carboxylic acids acidic?

  to be and acid it must be aqueous and only small chained carboxylic acids dissolve in water.
• Carboxylic acids react with metal carbonates to produce what?

  Salt, water, carbon dioxide
• What is the functional group test for carboxylic acids?

  When reacted with metal carbonates the effervescence can be bubbled through limewater to confirm it is carbon dioxide. If the solution turns milky you know it was a carboxylic acid used.
• What is esterification?

  Heating a carboxylic acid with an alcohol in the presence of a strong acid under reflux to produce an ester and water.
• Carboxylic acid + alcohol =

  Ester and water
• what conditions are esterification reactions?

  Heat, reflux, strong acid catalyst.
• What is the functional group of esters?

  COO
• When naming an ester which part does the carboxylic acid name?

  COO

  
  

  E.g. CH3CHOOCH2CH2CH3 is named propyl ethanoate.
• Name three uses of esters.

  Sweet smell - perfumes and flavourings.

  
  

  Polar and have low boiling points - solvents and printing inks.

  
  

  Flexible - added to plastics.
• What are the two types of ester hydrolysis?

  Acid and base
• What are the conditions for acid hydrolysis?

  Dilute acid, reflux.
• Is acid hydrolysis reversible?

  Yes.
• Give a word equation for acid hydrolysis?

  Ethyl ethanoate + water =(reversible) Ethanoic acid + ethanol.
• Is base hydrolysis reversible?

  No
• What are the conditions for base hydrolysis?

  Alkali reflux warm
• Why are reactions of ester hydrolysis refluxed?

  Because esters are volatile.
• Give a word equation for the base hydrolysis of an ester.

  Ethyl ethanoate + OH- + carboxylate ion + ethanol.
• Why is bas hydrolysis not ideal?

  An extra step is required to remove the carboxylate ion.
• Why is base hydrolysis favoured over acid hydrolysis?

  Forward reactions have a higher yield and therefore are better for the economy.
• What are fatty acids?

  long chained carboxylic acids
• Are animal fats saturated or unsaturated?

  saturated
• Why are saturated fats solid at room temp?

  Because they have no kinked chains/double bonds they lay close together meaning the net force of VDWs is stronger.
• Are vegetable oils saturated or unsaturated?

  unsaturated
• Why are unsaturated fats liquid at room temp?

  The bent hydrocarbon chains means they don't nicely fit together and the net forces of VDWs aren't as strong.
• Write the word equation for esterication with glycerol.

  3 fatty acids + glycerol (reversiable) = ester (triester) + 3 water.
• What two products do triesters react to form?

  Biodiesel and salt (soap)
• Give the name reaction to form soap.

  Hydrolysis of fats and oils.
• Give the word equation of formation of soap.

  Triester + 3 dilute potassium hydroxide = glycerol + 3 salt
• Give the word equation for the formation of biodiesel.

  Triester + 3 methanol = glycerol + methyl ester.
• Give the functional group of amides.

  CONH2
• Give the functional group of an acrylic chloride.

  COCl
• Give the functional group of an N-substituted amide.

  RCONHR
• Give the functional group of acid anhydrides.

  (RCO)2O
• Acyl chloride + water =?

  Carboxylic acid + HCl gas