| 摘要 |
<p>A composition of bibenzimidazoles of the Formula (I): <CHEM> wherein X & Y which may be the same or different and, taken together, contain a total of from 12 to 52 saturated carbon atoms, are (a) each selected from -R, -COR, -CH2COOR, -CH(COOR)2 and -COOR; or (b) together form a group selected from <CHEM> wherein R is an optionally substituted hydrocarbyl group, A & B taken together with the two carbon atoms to which they are linked form an optionally substituted benzene ring; and C & D taken together with the two carbon atoms to which they are linked form an optionally substituted benzene ring; characterised in that at least 50% by weight of the bibenzimidazoles in the composition are of Formula (II) <CHEM> wherein X and Y are as hereinbefore defined; T, U, V & W which may be the same or different, are H, R<1> or OR<1> provided at least one of T, U, V & W is R<1> or OR<1>; and R<1> is C1-6-alkyl; which are suitable for use in the extraction of zinc from aqueous solutions of zinc in the presence of other metals.</p> |
