Palladium acetylacetonate-Triphenylphosphine

Prepared as described by P. G. Charles and M. D. Pawlikowski in J. Phys. Chem.,62, 440 (1958) for Ni (acac>2. Palladium acetylacetonate and triphenylphosphine were crystallized and stored under argon. 

Palladium compounds have also been reported to stabilize unexposed areas to heat.199 The compounds disclosed include the complexes of triphenylphosphine, bipyridine, acetylacetone and dimethylglyoxime. Preferred compounds appear to be the acac analogs. 

The mixed-ligand complex 853, containing C- and O-bound acetylacetonate anions, was isolated as a result of interaction (4.22) of palladium /h.v-(acetylacetonate) with triphenylphosphine [91] ... 

A detailed study of over 45 catalysts, primarily from Group VIII metal salts and complexes, showed palladium(II) compounds to be the most effective in the dehydrogenation of a variety of aldehydes and ketones. Soluble palladium(II) salts and complexes such as dichloro(triphenylphosphine)palladium(II) and palladium(II) acetylacetonate have been shown to be optimal, with the salts of rhodium, osmium, iridium and platinum having reduced efficacy. Since the dehydrogenation reaction is accompanied by reduction of the palladium(II) catalyst to palladium(O), oxygen and a cooxidant are required to effect reoxidation. Copper(II) salts are favored cooxidants, but quinones, and especially p-benzoquinone, are also effective (Scheme... 

The solvent properties of alcohols with short carbon chains are similar to those of water and such alcohols could be used as the nonaqueous catalyst phase when the products are apolar in nature. The first commercial biphasic process, the Shell Higher Olefin Process (SHOP) developed by Keim et al. [4], is nonaqueous and uses butanediol as the catalyst phase and a nickel catalyst modified with a diol-soluble phosphine, R2PCH2COOH. While ethylene is highly soluble in butanediol, the higher olefins phase-separate from the catalyst phase (cf. Section 2.3.1.3). The dimerization of butadiene to 1,3,7-octatriene was studied using triphenylphosphine-modified palladium catalyst in acetonitrile/hexafluoro-2-phe-nyl-2-propanol solvent mixtures [5]. The reaction of butadiene with phthalic acid to give octyl phthalate can be catalyzed by a nonaqueous catalyst formed in-situ from Pd(acac)2 (acac, acetylacetonate) and P(0CeH40CH3)3 in dimethyl sulfoxide (DMSO). In both systems the products are extracted from the catalyst phase by isooctane, which is separated from the final products by distillation [5]. 

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