350620-84-7Relevant academic research and scientific papers
Highly active, recyclable catalyst for the manufacture of viscous, low molecular weight, CO-ethene-propene-based polyketone, base component for a new class of resins
Mul, Wilhelmus P,Dirkzwager, Hendrik,Broekhuis, Antonius A,Heeres, Hero J,Van der Linden, Adrianus J,Guy Orpen
, p. 147 - 159 (2002)
A highly active, recyclable homogeneous palladium(II) catalyst is described for the manufacture of viscous, low molecular weight CO-ethene-propene-based polyketone (Carilite Oligomer), used for the manufacture of a new class of resins (Carilite Resins). The catalyst is composed of palladium acetate, and a sulfonated diphosphine ligand, bdompp-S (1,3-bis(di-(2-methoxy, 5-sulfonatophenyl)phosphino)propane). In comparison with its non-sulfonated counterpart this catalyst not only exhibits a much more favourable partitioning coefficient in liquid-liquid separation of the polyketone product and solvent, but it also exhibits an approximately 2.5 times higher catalytic activity (up to 11.2 kg PK(g Pd)-1h-1) in the manufacture of PK-PE-30 (polyketone terpolymer built up of CO, ethene and propene in a molar ratio of 100:30:70). A variety of salts were found to exert a positive influence on the activity of the catalyst. Possible origins of this 'salt-effect' are briefly discussed. The bdompp-S ligand was synthesised by sulfonation of bdompp using either a boric acid-oleum mixture or sulfuric acid as the sulfonation reagent. The product was isolated either as sodium-salt (bdompp-S[Na]4·nNa2SO4), by extraction with methanol after neutralisation, or, in acidic, hydrated form (bdompp-S[H]4·nH2O), via a new and highly efficient procedure, i.e. cooling the reaction mixture after dilution with water. The X-ray crystal structure of bdompp-S[H]4·nH2O is discussed.
In situ preparation of palladium diphosphane catalysts
Marson, Angelica,Van Oort, A. Bart,Mul, Wilhelmus P.
, p. 3028 - 3031 (2007/10/03)
The efficiency of a superficially simple preparation procedure for palladium-diphosphane catalysts has been examined. Preparation of Pd(dppe)X2 in situ by mixing equimolar amounts of Pd(OAc)2 and 1,2-bis(diphenylphosphanyl)-ethane (dppe) in methanol in the first step unexpectedly affords the bischelate [Pd(dppe)2](OAc)2 as the (main) kinetic product. Subsequently, the slow reaction of [Pd(dppe)2]-(OAc)2 and unreacted Pd(OAc)2 forms the thermodynamically favored monochelate [Pd(dppe)(OAc)2] (following first-order kinetics). Conversion of the bischelate into the monochelate stops after addition of strong acid (HX) in the second step, thus affording a mixture of active - Pd(dppe)X2 - virtually inactive - [Pd(dppe)2]X2 - and unstable - PdX2 - species. This procedure was also evaluated for some other diphosphane ligands and methods are given to overcome the encountered problem.
