Modification chimique des polyalcadiènes par les composés du type CX 3Z—I Addition catalysée des composés CCl 3Z sur les polybutadiènes-1,2

Abstract

The influence of catalysis on chemical modification of 1,2-polybutadienes ( M n < 10,000) by CX 3Z reagents (X = halogen; Z = functional group or halogen), in order to obtain polymers soluble in common solvents, has been studied. The work has been carried out with carbon tetrachloride, trichloromethylphosphonyldichloride (CCl 3POCl 2) and ethyl trichloroacetate (CCl 3CO 2Et) in the presence of solvents such as C 6H 6, CH 2Cl 2. Among the compounds tested as catalysts for the addition of CX 3Z to 1,2-polybutadiene (transition metal salts and complexes; radical initiators) only the systems formed with metal salts such as CuCl 2, FeCl 3, RuCl 3 3H 2O, Fe 2(CO) 9 and Cl 2Ru(PPh 3) 3 were found to show high catalytic activity. The most active is Cl 2Ru(PPh 3) 3: used without or with cocatalysts (Et 3NHCl/benzôin, alcohols), it leads always, to the best yields whatever the nature of CX 3Z. The activity of the other catalysts is generally dependent on CX 3Z structure. Some secondary reactions (cross-linking, cyclization, transesterification) have been found.