Homogeneous telomerization of 1,3-butadiene with alcohols in the presence of palladium catalysts modified by hybrid chelate ligands

• Published in: Journal of molecular catalysis. A, Chemical Vol. 140; no. 2; pp. 139 - 155
• Main Authors: Benvenuti, Federica, Carlini, Carlo, Marchionna, Mario, Patrini, Renata, Raspolli Galletti, Anna Maria, Sbrana, Glauco
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 09-04-1999; Elsevier
• Subjects: 1,3-Butadiene telomerization; Catalysis; Catalytic reactions; Chelate ligands; Chemistry; Exact sciences and technology; General and physical chemistry; Higher alcohols; Methanol; Octadienyl ethers; Palladium catalysts; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Palladium catalysts; Octadienyl ethers; Chelate ligands; Higher alcohols; 1,3-Butadiene telomerization; Methanol; Hydrocarbon; Ligand; Palladium II; Telomerization; Chelating agent; Palladium complex; Palladium; Experimental study; Butadiene
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/S1381-1169(98)00234-9

1,3-Butadiene telomerization with methanol and higher alcohols was investigated in the presence of different palladium(0) and palladium(II) complexes based on hybrid chelate ligands. When P
∩O ligands were used, the resulting palladium complexes displayed poor activity and low selectivity to telomers, also in the presence of alkoxide promoters. Even worse performances were found when ionic palladium(II) or neutral palladium(0) and palladium(II) complexes based on N
∩N chelate ligands were employed in combination with alkoxide promoters. Better results were obtained by using ionic palladium(II) complexes with P
∩N
∩N ligands in combination with an alkoxide promoter. Very promising results were achieved when the telomerization reaction was catalyzed by palladium(0) complexes obtained in situ from Pd(dba)
2 and P
∩N ligands. The data are discussed and interpreted in terms of different capability of the chelate ligands, depending on their size and donor power, to give palladium complexes with metal sites at low oxidation state characterized at the same time by a sufficient stability and coordinative unsaturation to promote high catalytic activity and selectivity.