Abstract: A compound for effecting molecular weight control in polymerisation is a CoII chelate of formula, wherein each group R is an organic cyclic group which, independently, is a monovalent group which comprises a cyclic structure or taken together as two adjacent groups provides a divalent group, and wherein further at least one of the groups R includes at least one heteroatom selected from 0, N, S, P, halogen and Si, which heteroatom provides a substituent group or part of a substituent group on the cyclic structure, or a heteroatom of a heterocyclic ring of the cyclic structure; and wherein each group Q is independently selected from F, Cl, Br, OH, C.sub.1-12 alkoxy and C.sub.1-12 alkyl; or being a CoIII analogue of the cobalt II chelate of formula in which the Co atom is additionally covalently bonded to H, a halide or other anion, or a homolytically dissociable organic group. Free-radical polymerication of at least one ethylenically unsaturated monomer is carried out in the presence of such a compound.

Abstract: Gallium is efficiently extracted from strongly basic solutions containing aluminates by extractants having the tris- and/or tetrakis(2-hydroxybenzyl)-1,2-diaminoethane chemical moiety. The diaminoethane derivative may be used together with a hydrocarbyl 8-hydroxyquinoline and/or with a tertiary carboxylic acid.

Abstract: Gallium is efficiently extracted from strongly basic solutions containing aluminates by extractants having the tris- and/or tetrakis (2-hydroxybenzyl)-1,2-diaminoethane chemical moiety. The diaminoethane derivative may be used together with a hydrocarbyl 8-hydroxyquinoline and/or with a tertiary carboxylic acid.