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PREPARATION OF CARBONATE-FREE BASES JACK E. POWELL and MAYNARD A. HILLER Institute for Atomic Research and Iowa State Cdlege, Ames, Iowa
VARIOUS methods are kno\vn for producing carbonatefree base to be used in titrations. For example, Na&03 is relatively insoluble in saturated NaOH solut,ions so it can be filtered off readily. KICO3, however, is more soluble in KOH and removal of C03- by this method is not, feasible. A method involving the use of anion-exrhange resins has been proposed' for the preparation of carbonate-free KOH. However, the exchange c.onstant between C1- and OH- is not very favorable and several liters of KOH must be passed through the anion bed before all C1-
' DAVIES, C . W.,AND n. H.
( 19.50).
~AXCOLLAS,
Nature, 165, 238
is gone from the eluate. We wish to propose a new method for producing carbonate-free as well as chloridefree KOH. The concentrated KOH is treated with a sufficient amount of Ba(OH)* to precipitate all of the COa--. The solution is then filtered, protected from the air by ascarite, diluted with freshly boiled water, and passed through a strong acid cation-exchange hed in the K+ cycle. Such resins are Dowex-50 or Amberlite IR120. Ba++ is preferentially adsorbed and the effluentKOH is caught in a protected flask from which the air has been displaced by He. Analysis of I(OH produced in this way showed no G O 3 - as well as no C1-. The method is also applicable to the preparation of carbonate-free NaOH, NHIOH, etc.
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