| 摘要 |
<p>The invention provides a metathetic process of the type M'X + M'Y = M'Y + M'X, where M' differs from M' and the reagents and the products are water-soluble salts, comprising the steps of (a) transferring a solution of M'Y through at least one column containing cation exchanger beads loaded with M' cations, obtained in step (b) hereinafter, whereby cation exchange takes place to form a solution of M'Y and cation exchanger beads loaded with M', and (b) transferring a solution of M'X through said column containing cation exchanger beads loaded with M' obtained in step (a) above, whereby cation exchange takes place to form a solution of M'X and cation exchanger beads loaded with M'; characterized in that both M' and M' are selected from the group consisting of sodium, potassium and ammonium; X and Y are different anions; two types of cation exchanger, A and B, are used in the process; cation exchanger A is more acidic than cation exchanger B; in step (a), the solution of M'Y is first transferred through beads of cation exchanger A and then through beads of cation exchanger B, both of which are loaded with M' cations obtained in step (b), whereby cation exchange takes place on both cation exchangers to form a solution of M'Y and to form cation exchanger beads loaded with M'; and in step (b), the solution of M'X is first transferred through beads of cation exchanger B and then through beads of cation exchanger A, both of which are loaded with M' cations obtained in step (a), whereby cation exchange takes place on both cation exchangers to form a solution of M'X and to form cation exchanger beads loaded with M'.</p> |
