High molecular weight polyketones by CO-ethene copolymerization catalysed with Pd(II)-phosphine complexes in homogeneous phase in formic acid

[PdX2(PPh3)(2)]/PPh3 (X = HCOO, AcO, NO3, Cl, TsO; X-2 = SO4) and [Pd(AcO)(2)(dppf)] in HCOOH with 5% H2O catalyse the CO-ethene copolymerization to high molecular weight polyketones (2700-2900 gPK (gPd.h)(-1) at 333 K, 4.5 MPa of CO/ethene 1/1; Mn = 20000-40000 Da). Catalysis occurs in homogeneous phase because the PK is soluble in the reaction medium. The polydispersity Mv/Mn is close to 2 dL.g(-1), as expected for a homogeneous process. With the dppf-based catalyst, when the copolymerization is carried out in water/formic acid = 60/40 (mol/mol), the PK precipitates during the copolymerization and the polydispersity rises to 3.16 dL.g(-1), in line with a process that becomes heterogeneous.

Automated summary

This study explores the synthesis of high molecular weight polyketones through CO-ethene copolymerization catalyzed by different palladium complexes in homogeneous and heterogeneous conditions. The results show that polyketones produced under homogeneous conditions have lower polydispersity compared to those synthesized under heterogeneous conditions.