Snamprogetti S.p.a.

Anic S.p.a.

Enichem Tecnoresine S.p.a.

Sergio Poggio

Gabriele Lugli

Alessandro Mazzei

Ugo Pedretti

Alberto Petri

Flame-resistant thermoplastic branched polycarbonates of high molecular weight are prepared from:

Flame-resistant polycarbonates containing units deriving from

A novel catalytic system is disclosed which is especially adapted for the polymerization and the copolymerization of aliphatic conjugated diolefines, the system comprising an organic compound of aluminum, a Lewis acid containing at least one halogen, and an organic compound of a lanthanide metal. The catalyst system has outstanding and hitherto unparalleled activity. The method of preparation of the catalytic system is also described in detail.

Polymerizing and copolymerizing diolefines, and means therefor

A new uranium allyl compound, represented by the formula: ##EQU1## WHEREIN R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5, which may be the same or different, are members of the group consisting of H, alkyl radicals containing from 1 to 10 C atoms, aryl radicals containing from 6 to 10 C atoms, cycloalkyl radicals containing from 4 to 10 C atoms, and alkyl aryl radicals containing from 7 to 10 C atoms, the dotted line linking the three carbon atoms indicates possible delocalization of the valence electrons of the double bond, X is an anion selected from Cl.sup.-, Br.sup.- and I.sup.- and n is an integer ranging from 1 to 3. The members of that group of compounds are useful, respectively, as catalysts in the stereospecific polymerization of diolefins and may be prepared by reacting a compound represented by the formula: ##EQU2## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 and the dotted line have the significance given above, with a compound represented by the formulae HX or X.sub.2, wherein X has the significance given above.

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Milan, Italy

Sergio Poggio