Abstract: A process of recovering cesium ions from mixtures of ions containing them and other ions, e.g., a solution of nuclear waste materials, which comprises establishing a separate source phase containing such a mixture of ions, establishing a separate recipient phase, establishing a liquid membrane phase in interfacial contact with said source and recipient phases, said membrane phase containing a ligand, preferably a selected calixarene as depicted in the drawing, maintaining said interfacial contact for a period of time long enough to transport by said ligand a substantial portion of the cesium ion from the source phase to the recipient phase, and recovering the cesium ion from the recipient phase. The separation of the source and recipient phases may be by the membrane phase only, e.g., where these aqueous phases are emulsified as dispersed phases in a continuous membrane phase, or may include a physical barrier as well, e.g.

Abstract: Phenylene sulfide oligomers are produced by heating at least one aromatic sulfide in an oxygen-containing gaseous atmosphere at an elevated temperature and for a period of time sufficient to form the oligomers. The oligomers can be cured by heating in an oxygen-containing atmosphere while the oligomers are being produced or in a subsequent step after production to yield cured oligomers having utility as coatings, films, and the like.

Abstract: Unsymmetrical aromatic sulfides are converted to symmetrical sulfides in a disproportionation reaction by heating, optionally in the presence of a free radical generator and/or oxygen-containing gas, at an elevated temperature and for a period of time sufficient to convert the unsymmetrical sulfides to symmetrical sulfides.