Distillation of a product from a reaction - part 1

Question 1

What are the stages generally in the synthesis of an organic liquid?

Answer 1

• preperation
  
  • react suitable quantities of the reactants to produce the crude product
  • the reactants are often heated under reflux
• seperation of the crude [rpdict
  
  • liquids seperated by simple or fractional distillation
• purification of the product
  
  • removes impurities such as unreacted regents and by-products and is carried out by solvent extraction
• dry
  
  • by swirling with a drying agent
• final distillation
  
  • indentiy and purity check
  • if the liquid is pire the boiling point will be sharp

Question 2

WHy are the reaction often slow when preparing an organic liquid

Answer 2

strong covalent bonds

Question 3

WHat is reflux

Answer 3

the conitnual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry

Question 4

why are the reactants added slowly to the reaction flask with cooling?

Answer 4

• reaction is often exothermic and adding reactants slowly with cooling disspiates the heat, preventing the temp of the reaction increases
• and advoding dangerous splashing or the the formation of side products

Question 5

What does heating under reflix consist of ? how does it work

Answer 5

• attaching a water-cooled condesner vertically to the reaction flask
• vapour from the boiling reaction mixture condenses and flow back into the reaction flask
• the condesner prevents vapour escaping and so that the reactants can be boiled fro a long period without and loss of vapour

Question 6

What are anti-bumping granules?

Answer 6

• small, rough pieces of silica that are added to the reaction before reflux
• most liquids do not boil smoothly
  
  • often form large bubbles at the bottom and moves abrubtly upwards, causing splashing
  • this is bumping
• anti-bumpiung granules provide a rough surface which small gas bubble can grow, hence avoid bumping
  
  • promote, smooth, even boiling

Question 7

What do you do if the liquid is flammible?

Answer 7

• flameless method
• less than 100 degrees
  
  • waater bath
• higher
  
  • electric heaitng handle

Question 8

WHy is distillation used when oxidising an aldehyde to a primary alcohol?

Answer 8

further heating would lead to further oxidation to a carboxylic acid