Organic Techniques Flashcards
what is refluxing and what does it do?
it ensures that no volatile organic substances are lost.
the mixture is heated in a flask with a vertical liebig condenser - this continuously boils, evaporates and condenses the vapours and recycles them back into the flask giving them time to react
what is distillation and how can it be carried out?
it separates substances with different boiling points.
- an example of when this may be needed to be used is in the oxidation of a primary alcohol - the two products can be separated.
what does separation do?
it removes any water soluble impurities from the product. once the reaction to form the product is completed, pour the mixture into a separating funnel and then add water.
shake the funnel and then allow it to settle. the organic layer and the aqueous later are immiscible so they separate out into two distinct layers - then run each separate layer off.
what does immiscible mean?
two solutions don’t mix
how can you remove traces of water from a mixture?
use an anhydrous salt. if you use separation to purify a product then the organic layer will end up containing traces of water so it has to be dried. to do this add an anhydrous salt. this is used as a drying agent - it binds to any water present to become hydrated
what is a good way to determine purity?
measuring the boiling point. if you have got a reasonable volume of liquid then you can determine its boiling point using a distillation apparatus. if you gently heat the liquid in the distillation apparatus until it evaporates you can read the temp at which it is distilled.
