Abstract: Styrenic polymers are brominated by a process comprising dispersing at least one Lewis acid catalyst in at least one inert halogenated solvent and contacting said Lewis acid catalyst dispersion with a solution of at least one ring-brominatable styrenic polymer in at least one inert halogenated solvent and at least one brominating agent.

Abstract: A biocidal composition is formed from an organotin compound covalently bonded to reactive silanol sites present on the surface of a silica compound to form a solid biocidal particle. Further, the solid biocidal particle can be admixed with a carrier or film-forming vehicle. A method of protecting a surface from fouling organisms is also provided by coating the surface with the subject biocidal composition while it is dispersed in a carrier or film-forming vehicle.

Abstract: A solid catalyst composition comprising a silica or silica-treated compound and a tin catalyst compound bonded to the surface of the silica compound which is not deactivated in the presence of silica or silica-treated compounds. A process for preparing the solid catalyst by contacting a silica compound containing reactive hydroxyl groups with a tin catalyst compound at a temperature range from about 130.degree. to 165.degree. C. under dynamic conditions whereby the tin catalyst compound bonds to the silica compound. Generally, after the reaction, at least a portion of the hydroxyl groups present on the silica compound are absent and, more preferably, substantially all the isolated hydroxyl groups are absent. A urethane composition containing the solid catalyst is also provided wherein the solid catalyst is not deactivated by the addition of silica or silica-treated compounds.