PMT flashcards carboxylic acids and esters

• 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?

  Yes, they form hydrogen bonds with water
• What are the intermolecular forces in carboxylic acids?

  Hydrogen bonds in solid state - very strong
• What are esters formed from?

  Carboxylic acids and alcohols
• What is the general formula of esters?

  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 alcohol group, then acid part
• What characteristic physical properties do esters have?

  Volatile, pleasant fruity smells
• What are some uses of esters?

  Flavourings, perfumes, solvents, plasticisers
• How could you distinguish carboxylic acids from other -OH containing compounds?

  Add NaHCO3; acids produce sodium salt
• 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?

  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
• What are carboxylic acid derivatives?

  Molecules with the acyl group from acids
• Name two acid derivatives and their functional groups.

  Acyl chlorides: RCOCl; Acid anhydrides: RCOOCR
• How do you form an acyl chloride?

  React carboxylic acids with SOCl2
• Draw the mechanism for the acylation of a nucleophile by an acid derivative.

  Mechanism involves nucleophilic attack on acyl carbon, followed by loss of leaving group.

  
• What are oxylic acid derivatives?

  Molecules with an acyl group from carboxylic acids
• Name two acid derivatives.

  Acyl chlorides and acid anhydrides
• What is the functional group of acyl chlorides?

  RCOCl
• What is the functional group of acid anhydrides?

  RCOOCR or (RCO)2O
• What is the mechanism for the acylation of a nucleophile by an acid derivative?

  • Nucleophile attacks the carbonyl carbon
  • Tetrahedral intermediate forms
  • Collapse of the intermediate
  • Leaving group departs
• What product is formed when ammonia acts as a nucleophile in acylation reactions?

  An amide
• Write the equation for the reaction of ethanoyl chloride and ammonia.

  CH3COCl + 2NH3 → CH3CONH2 + NH4Cl
• What is the mechanism for the reaction of ethanoyl chloride and ammonia?

  • Nucleophilic attack by ammonia
  • Formation of tetrahedral intermediate
  • Collapse of intermediate
  • Formation of amide and ammonium chloride
• What product is formed when a primary amine acts as a nucleophile in acylation reactions?

  N-substituted amide
• Write the equation for the reaction of ethanoyl chloride and methylamine.

  CH3COCl + CH3NH2 → CH3CONHCH3 + CH3NH3Cl
• What is the mechanism for the reaction of ethanoyl chloride and methylamine?

  • Nucleophilic attack by methylamine
  • Formation of tetrahedral intermediate
  • Collapse of intermediate
  • Formation of N-substituted amide and methylammonium chloride
• What product is formed when an alcohol acts as a nucleophile in acylation reactions?

  An ester
• Write the equation for the reaction of ethanoyl chloride and ethanol.

  CH3COCl + CH3CH2OH → CH3COOCH2CH3 + HCl
• What is the mechanism for the reaction of ethanoyl chloride and ethanol?

  • Nucleophilic attack by ethanol
  • Formation of tetrahedral intermediate
  • Collapse of intermediate
  • Formation of ester and HCl
• What product is formed when water acts as a nucleophile in acylation reactions?

  Carboxylic acid
• What is the name of the reaction when water is the nucleophile in acylation of acyl chlorides or acid anhydrides?

  Hydrolysis
• Write the equation for the reaction of ethanoyl chloride and water.

  CH3COCl + H2O → CH3COOH + HCl
• What is the mechanism for the reaction of ethanoyl chloride and water?

  • Nucleophilic attack by water
  • Formation of tetrahedral intermediate
  • Collapse of intermediate
  • Formation of carboxylic acid and HCl