Enichem S.p.a

Université Des Sciences Et Technologies De Lille

Jean-Francedillaois Pelletier

Karel Bujadoux

Andre Mortreux

Xavier Olonde

Emmanuel Adisson

Thomas Chenal

This dialkylmagnesium is represented by the formula R--(CH.sub.2 --CH.sub.2).sub.n --Mg--(CH.sub.2 --CH.sub.2).sub.n' --R', (E--O--E').sub.x, where R and R' each independently represent a C.sub.1 -C.sub.20 hydrocarbon residue, branched or not, substituted or not, of the alkyl, cycloalkyl or aralkyl type; n and n', identical or substantially identical, represent an average number of --CH.sub.2 --CH.sub.2 -- linkages such that the average number of carbon atoms in each of the two chains borne by Mg is greater than 20; E and E', identical or different, each represent an alkyl radical, linear or cyclical, branched or not; and 0.ltoreq.x.ltoreq.2, x being the average value of the number of moles of E--O--E' ether complexed to the dialkylmagnesium. In order to prepare a dialkylmagnesium of this type, ethylene is polymerized in an anhydrous, de-oxygenated hydrocarbonaceous solution by means of a catalyst Cp*.sub.2 MCl.sub.2 Li(OEt.sub.2).sub.2 (Cp*=a pentamethylcyclopentadienyl ligand; M=scandium, yttrium or a metal of the lanthanide series; Et=ethyl), in the presence of a dialkylmagnesium, soluble in the solvent, of the formula R--Mg--R', (E--O--E').sub.x, where R, R', E, E' and x are as defined above, as a chain-transfer agent, and the reaction is stopped before the polydispersity of the polymer product obtained exceeds 2, and preferably before it exceeds 1.5.

Growing community of inventors

La Garde, France

Jean-Francedillaois Pelletier