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Quaternary onium salts immobilized on silica gel
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Pellicular Supported Functions Based on Polypropylene Beads A. G u y o t , C.N.R.S., Vernaison, France Small spherical beads of isotactic polypropylene are produced upon recrystallization from a semi-diluted solution in the presence of additives. The size range is 10- 200 p.m depending on various parameters. Functionalization is obtained by a two-step procedure: first, peroxidation by ozone in a fluidized bed: second, polymerization of a functional monomer (chloromethylstyrene) with the supported peroxide as a part of a redox system Ungrafted polyrner is extracted before further derivatization. "l'o he published in Reactit.'e Poh'mers.
Catalysis with Polymeric Supports C. L o u c h e u x , Uni~,ersiO' of Lille, Lille, France Porous polymeric supports with various chemical compositions and structures were synthesized and functionalized. Then some catalytic species were bound in order to induce Fischer "lropsch-type reactions. The comparison with the same system used as a homogeneous catalyst emphasized a much larger olefin selectivity in the supported system. The catalytic activities are identical or better for the supported catalyst. The dimerization of ethylene was also investigated with specific supported catalysts. In this case, 1-butene selectivity was increased. In both cases the influence of the texture of the supports was studied. Not presented, intended for publication in Reactive Polymers.
Enhancement of Number and Activily of Sites on Functional Supported Polymers A. R e v i l l o n , C.N.R.S., Vernaison, France Macroporous styrene-divinylbenzene crosslinked copolymers with large pore volume and large pore diameter ha'.e been prepared. Either directly or after activation, attempts have been made to react them with free-radical initiators. These are a:,o compounds, either classical ones which are then fixed via chemical reaction, or formed m .~m~ m a series of steps. With model compounds the reactions are rather controlled and quantitative, whereas thev have moderate vield with supports, due to phase transfer problems, difficult separations of products, and limited conversions. Yet, in methyl methacrylate polymerization, traces of macroinitiator are found but the moderate molecular weight indicates a low number of active sites per chain. Intended for publication in Reactire Polymers.
Quaternao' Onium Salts Immobilized on Silica Gel P. T u n d o , University of Turin, Turin, Italy The title supports can be used as phase-transfer catalysts, micellar catalysts, anion exchangers and supported reagenls. Depending on the degree of functionalization and polarity of the positive center, they show properties quite different from the corresponding systems bonded to crosslinked polystyrene. Rose Bengal immobiliTed on silica gel via anion exchange has a high activity in promoting photooxidations with singlet oxygen. Not presented
Pellicular Supported Functions Based on Polypropylene Beads A. G u y o t , C.N.R.S., Vernaison, France Small spherical beads of isotactic polypropylene are produced upon recrystallization from a semi-diluted solution in the presence of additives. The size range is 10- 200 p.m depending on various parameters. Functionalization is obtained by a two-step procedure: first, peroxidation by ozone in a fluidized bed: second, polymerization of a functional monomer (chloromethylstyrene) with the supported peroxide as a part of a redox system Ungrafted polyrner is extracted before further derivatization. "l'o he published in Reactit.'e Poh'mers.
Catalysis with Polymeric Supports C. L o u c h e u x , Uni~,ersiO' of Lille, Lille, France Porous polymeric supports with various chemical compositions and structures were synthesized and functionalized. Then some catalytic species were bound in order to induce Fischer "lropsch-type reactions. The comparison with the same system used as a homogeneous catalyst emphasized a much larger olefin selectivity in the supported system. The catalytic activities are identical or better for the supported catalyst. The dimerization of ethylene was also investigated with specific supported catalysts. In this case, 1-butene selectivity was increased. In both cases the influence of the texture of the supports was studied. Not presented, intended for publication in Reactive Polymers.
Enhancement of Number and Activily of Sites on Functional Supported Polymers A. R e v i l l o n , C.N.R.S., Vernaison, France Macroporous styrene-divinylbenzene crosslinked copolymers with large pore volume and large pore diameter ha'.e been prepared. Either directly or after activation, attempts have been made to react them with free-radical initiators. These are a:,o compounds, either classical ones which are then fixed via chemical reaction, or formed m .~m~ m a series of steps. With model compounds the reactions are rather controlled and quantitative, whereas thev have moderate vield with supports, due to phase transfer problems, difficult separations of products, and limited conversions. Yet, in methyl methacrylate polymerization, traces of macroinitiator are found but the moderate molecular weight indicates a low number of active sites per chain. Intended for publication in Reactire Polymers.
Quaternao' Onium Salts Immobilized on Silica Gel P. T u n d o , University of Turin, Turin, Italy The title supports can be used as phase-transfer catalysts, micellar catalysts, anion exchangers and supported reagenls. Depending on the degree of functionalization and polarity of the positive center, they show properties quite different from the corresponding systems bonded to crosslinked polystyrene. Rose Bengal immobiliTed on silica gel via anion exchange has a high activity in promoting photooxidations with singlet oxygen. Not presented