Extraction Flashcards
What is the purpose of extraction
to separate compounds based on solubility between two immiscible layers
what is the partition coefficient
it is a measure of how a substance distributes itself between two immiscible solvents at equilibrium
How can we efficiently extract solvents
it is more efficient to extract small volumes multiple times
for an extracting solvent, do we want a solvent with a higher or lower boiling point?
we want a lower boiling point so that it is easier to boil off
why is density important
the solvent with the lower density will be on top while the higher density solvent will be on the bottom
Why do we shake the separatory funnel thoroughly
it mixes the layers and pulls the organic compounds out of the aqueous layer
why do we need to vent the separatory funnel
as we shake it, vapor pressure can build u and explode
why do we wait before draining the separatory funnel
the layers need time to separate
why do we drain one layer from the bottom and one on top
to prevent contamination of the organic and aqueous layers
how do we tell what layer is aqueous
you can do a water test and see which layer the water disappears in
what does the organic layer contain
it contains neutral organic compounds
what do we do with the organic layer
we wash it with aqueous phases to remove excess aqueous molecules
what are the aqueous phases we use for washing
NaCl and NH4Cl
what are the drying agents we use and why do we use them
MgSo4, CaCl2, Na2SO4, K2CO3
they are drying agents that remove traces of water
why do we evaporate our organic layer after we are done
it removes excess solvent and leaves the compound of interest
what does the aqueous layer contain
it contains undesired inorganic compounds
what do we do with the aqueous layer once we obtain it
we can extract it multiple times to obtain the desired compiund
in an acid-base extraction, what do we do with the acqueous layer
we neutralize it and extract with a fresh organic solvent
Why do we do acid-base extractions
it allows us to separate two organic compounds by converting one into a water soluble salt
what types of organic compounds can be made water soluble
acidic and basic compounds
how can acidic compounds be made water soluble
they can be deprotonated with a basic wash
what are the two acidic compounds we can make water soluble
phenols and carboxylic acids
what are the basic compounds that we can make water soluble
amines
how can basic compounds be made water soluble
they can be protonated with an acidic wash
