Practical organic and bio-chemistry / by R.H.A. Plimmer.

  • Robert Plimmer
Date:
1915
Catalogue details

Licence: Public Domain Mark

Credit: Practical organic and bio-chemistry / by R.H.A. Plimmer. Source: Wellcome Collection.

    41/660 (page 21)
    CONDENSER 4) een — eta ele | E D A ToB= SINCHES CToD=62 ” EtToD=52 » BroF=3 » TO FLASK (v) Mother Liquor. The mother liquor generally contains some solid in solution, which is to be recovered. ‘The impure crusts, if any, are added to the liquid and the liquid is concentrated by distilling or evaporating (p. 13) until crystals begin to separate. The solution is poured or filtered into a beaker and allowed to cool; a second crop crystallises out and is treated as above. A third and more crops may be obtained on further concentration. These are not so pure as the original crop, but may be recrystallised and obtained pure. *(vi) Decolorising Solutions. ! Substances containing tarry or resinous impurities or colouring matter cannot sometimes be freed from them by simple recrystallisation. During recrystallisation and while the solid is in solution (especially aqueous or alcoholic) the solution is boiled for 2-5 minutes or longer with a small quantity of blood charcoal which is removed by filtration. The first portions of filtrate generally require filtering again through the same paper as the finely divided charcoal passes through at first. To remove colouring matter from a solution which should be colour- less, prolonged boiling with several quantities of charcoal is sometimes necessary. The purification by crystallisation of about 5 gm. benzoic acid, oxalic acid, and succinic acid from water and of urea from alcohol serve as simple examples of the method of recrystallisation.