Abstract: A complexing ligand for forming a complex with a cation, the ligand comprising an aromatic component including two or more attachment sites for the cation, an optionally substituted amine, such as an aminoalkylene group, and a hydrocarbon chain of from 1 to 12 carbon atoms in length. The amine component of the ligand is capable of taking on an internal counterion (H+) so that the complex of the target cation and ligand has an overall neutral charge. Such ligands can be used to extract a target cation or cations from an aqueous solution. This has particular application for the separation of aluminium and silicon in aqueous liqors in a Bayer process. The ligand can be a simple compound formed by the Mannich condensation of catechol with formaldehyde and an amine. The ligand may alternatively be a bis-ligand, a polymer or an ion exchange resin. A range of new compounds and intermediates are also described.

Abstract: The present invention relates generally to improved processes for free radical polymerization, particularly to improved processes in which it is possible to control the growth steps of the polymerization to produce relatively short chain length homopolymers and copolymers, including block and graft copolymers, and further relates to new initiators which find particular application in the improved processes. Such initiators have the general structure of Formula I ##STR1## wherein X represents a group having at least one carbon atom and is such that the free radical X.sup.. is capable of polymerizing the unsaturated monomer by free radical polymerization, and the radical functionality resides on the or one of the carbon atoms,R.sup.1, R.sup.2, R.sup.5 and R.sup.6 represent the same or different straight chain or branched substituted or unsubstituted alkyl groups of a chain length sufficient to provide steric hindrance and weakening of the O--X bond, andR.sup.3 and R.sup.

Abstract: A security token, such as a bank note or identity card, comprises a sheet-like substrate made up from film of transparent bi-axially oriented polymer coated with layers of opaque and heat activated adhesive material. The opaque layer is applied in such a way as to leave a transparent area for inspection of a security device, for example, a diffraction grating, incorporated in the polymer film. The substrate may bear printed or other identifying indicia and is protected with an intimately bonded layer of transparent polymeric material.