Some Factors Influencing Distribution Coefficients of Trace Amounts of M2+ Ions During the Crystallization of Mn(CH3COO)2·4H2O

Abstract

Distribution coefficients,D_2/1 (Henderson – Kracek, Khlopin) of trace amounts of Ni²⁺,Mg²⁺, Cu²⁺, Co²⁺, Zn²⁺, Cd²⁺, Ca²⁺, and Sr²⁺ have been determined during the crystallization of Mn(CH₃COO)₂·4H₂O. Their dependencies on several properties of co-crystallizing acetate hydrates M(CH₃COO)₂·nH₂O as well as co-crystallizing M²⁺ ions have been analyzed. The D_2/1 values fall in the range from 0.011 (D_Cu) to 0.28 (D_Co) and indicate the possibility of effective removal of trace amounts of most investigated ions during the crystallization of Mn(CH₃COO)₂·4H₂O at 25 °C. They generally do not depend directly on most investigated factors, but those of Mg²⁺, Ni²⁺ and Co²⁺ ions, which form acetate tetrahydrates like Mn(CH₃COO)₂·4H₂O, closely depend on electronegativity of the elements as well as solubility and η parameter and may be estimated on the basis of the mentioned properties using simple formulae.

Keywords: Crystallization, manganese(II) acetate tetrahydrate, Henderson-Kracek, Khlopin distribution coefficients, D