Hybrid polyimide/silica materials were prepared from polyimides bearing reactive functions along the polymer backbone, which can react with. The silica phase was formed by sol–gel process using ammonium hydroxide catalyst. Silica fillers prepared under basic conditions were compared with materials prepared using chlorhydric acid. The synthesized hybrid materials were characterized by TGA, IRTF, and NMR. The density of the different systems was also measured. The morphology of these hybrid systems were investigated by both scanning and transmission electron microscope. Thermal properties of the composites were also evaluated by DSC and DMA. The morphology of silica fillers highly depends on the catalyst, on the reaction conditions of the sol–gel process, and the linking formation with the polyimide. It results that optimized conditions lead to homogeneous hybrid films containing 12 wt % of silica particles of about 20 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1891–1902, 2008

A series of 4‐fluoro‐5‐(perfluoroalkyl)pyrazoles has been prepared by heterocyclization of hemiperfluoroenones 3 or synthetic equivalents 1 and 2 with methylhydrazine. Compounds 1−3 were obtained by reaction of acylsilanes and perfluoroorganometallic reagents. The fluorinated pyrazoles could also be prepared in a one‐pot reaction from the starting acylsilanes. This method is very general and has been applied to aromatic, aliphatic and carbohydrate derivatives, as well as to bis(pyrazole) derivatives. The reaction is completely regiospecific and the regiochemistry has been determined by HMBC correlations, 19F‐1H and 1H‐1H NOE and by comparison of chemical shifts and carbon‐fluorine coupling constants of ring pyrazole carbon and fluorine atoms.

The methanolysis of three neutral organophosphorus esters (a phosphonate, a phosphonothioate, and a phosphorothionate) promoted by several polymer-supported Zn(II) or Cu(II) containing catalysts was studied. The catalysts consist of a Zn(II) or Cu(II) complex with 1,5,9-triazacyclododecane or phenanthroline attached to a porous polystyrene resin. In each case, the polymer supported catalyst showed activity at near neutral sspH in methanol (8.38) and ambient temperature and provided accelerations of up to a factor of 2.9 × 106 relative to the background reaction at sspH 9.05. The solid materials could be reused several times and could be reactivated when the activity diminished. Various polymers of different porosity and extent of cross-linking were studied, with the net result being that larger porosities offer the best reactivity for catalyzed methanolysis of these OP species in methanol. This is explained by different parameters including the accessibility to reactive sites, the increase of concentration of catalytic sites on the surface of the polymer, and some cooperative effects between neighboring catalytic groups.Key words: functionalized polymer, metal containing, methanolysis, organophosphorus pesticides and CW agents, catalyst.

No abstract