Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

What properties should a solvent have? (When purifying a product) watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    I was just wondering, what are the main, important, properties that a solvent should have? (ideally when purifying a product or in general)
    Offline

    3
    ReputationRep:
    (Original post by AY100)
    I was just wondering, what are the main, important, properties that a solvent should have? (ideally when purifying a product or in general)
    You should select an appropriate solvent such that the the desired substance dissolves fully when it is hot, and be sparingly soluble or insoluble in the cold solvent.

    Theoretically, you want a solvent such that the impurity has a higher solubility than that of the desired substance. Of course this is usually impossible because you don't know what this impurity is.
    But you don't need to be concerned with that

    a) you just assume (at least I've been taught) that the impurities have a higher solubility anyway.

    b) even if some of the impurities recrystallise, since the impurities are in such minute quantities, the concentration of recrystalled impurities is going to be even lower, in fact, it's likely that the solubility exceeds the quantity of the impurity because it's so tiny.
    You can redo the recystallisation method again and again to reduce the percentage of the impurity even more and more

    There's probably plenty other properties...
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by RMNDK)
    You should select an appropriate solvent such that the the desired substance dissolves fully when it is hot, and be sparingly soluble or insoluble in the cold solvent.

    Theoretically, you want a solvent such that the impurity has a higher solubility than that of the desired substance. Of course this is usually impossible because you don't know what this impurity is.
    But you don't need to be concerned with that

    a) you just assume (at least I've been taught) that the impurities have a higher solubility anyway.

    b) even if some of the impurities recrystallise, since the impurities are in such minute quantities, the concentration of recrystalled impurities is going to be even lower, in fact, it's likely that the solubility exceeds the quantity of the impurity because it's so tiny.
    You can redo the recystallisation method again and again to reduce the percentage of the impurity even more and more

    There's probably plenty other properties...
    Thanks!

    ----------------

    Does anyone else care to help me?
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 8, 2016
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.