organic chemistry lab and why is water the first choice for recrystallization when all factors are equal?
2 answers
This isn't my subject area; one of our chem teachers will probably repond within 12 hours.
organic chemistry lab and why is water the first choice for recrystallization when all factors are equal?
Not quite sure what you mean by "all factors are equal"
On the plus side:
water is cheap,
water can easily handled with out PPE,
pH is easily adjusted,
dissolves a wide range of materials,
can be handled in the open lab,
....you can probably come up with more
On the negative side
High latent heat means more expensive to evapotate.
Higher viscosity can mean more difficult to filter (especially on a large scale) than organic solvents.
Hot water is quite agressive and can cause some functional groups to hydrolyse (e.g. esters).
Last traces of water can be difficult to remove.
Can cause organic impurities to be entrained in the crystals if the water solution is not washed with an organic solvent.
....again you can come up with some more.
Not quite sure what you mean by "all factors are equal"
On the plus side:
water is cheap,
water can easily handled with out PPE,
pH is easily adjusted,
dissolves a wide range of materials,
can be handled in the open lab,
....you can probably come up with more
On the negative side
High latent heat means more expensive to evapotate.
Higher viscosity can mean more difficult to filter (especially on a large scale) than organic solvents.
Hot water is quite agressive and can cause some functional groups to hydrolyse (e.g. esters).
Last traces of water can be difficult to remove.
Can cause organic impurities to be entrained in the crystals if the water solution is not washed with an organic solvent.
....again you can come up with some more.
1 answer