Motoo Hazama

A practical convenient homogeneous palladium-phosphine catalysis for hydrocarbonylation of chlorobenzenes

Abstract Significant catalytic activity as well as high selectivity of benzoic acid has been found for hydrocarbonylation of chlorobenzene by using a catalyst system composed of PdCl2(PCy3)2K2CO3 aqueous solution-triethylamine (Cy: cyclohexyl).

Selective reduction of aromatic nitro compounds affording aromatic amines under CO/H2O conditions catalyzed by phosphine-added rhodium and ruthenium carbonyl complexes

Abstract High catalytic activities for the selective reduction of aromatic nitro compounds to the corresponding amines under the mild reaction conditions of room temperature and 1 atm of CO were found to be exhibited by chelatephosphine (dppe, dppm, etc.; dppe: 1,2-bis(diphenylphosphino)ethane, dppm: bis(diphenylphosphino)methane)-added rhodium and ruthenium carbonyl complexes in a 5 N NAOH aqueous solution. The reduction proceeded not only with high catalytic activities, but also with remarkably high nitro group selectivities; for example, 1-nitroanthraquinone afforded 1-aminoanthraquinone without other unsaturated groups (such as CO) being reduced. PR 3 -added Rh(CO) 2 (acac) complexes (PR 3 : PEtPh 2 , PEt 2 Ph, PEt 3 , etc.; acac: acetylacetonato) in diglyme in a 5 N NaOH aqueous solution were also found to show significant catalytic activities for the reduction of aromatic nitro compounds under mild CO/H 2 O conditions. Both electronic and steric factors of phosphine ligands are important in making this reaction proceed at such remarkable rates.

Efficient synthesis of 2,3-dimethylbutenes by dimerization of propylene using nickel-phosphine catalyst in the presence of strong sulfonic acids and/or dialkyl sulfates. Remarkable effect of strong sulfonic acids and/or dialkyl sulfates

Abstract Remarkable catalytic activities as well as high selectivities have been found for dimerization of propylene catalyzed by the nickel-phosphine system composed of nickel naphthenate/P(cyclo-C 6 H 11 ) 3 /AlEt 3 /2,4,6-trichlorophenol (TCP) especially in the presence of strong sulfonic acids (CF 3 SO 3 H, MeSO 3 H) or dialkyl sulfates (Me 2 SO 4 and Et 2 SO 4 ). The catalytic activity was further increased upon the combination of these effective additives. The desired C 6 olefins such as 2,3-dimethylbut-1-ene (DMB-1), 2,3-dimethylbut-2-ene (DMB-2, TMEN) could be obtained in relatively high yields by using these catalysts (selectivity of dimers = 70–80%: selectivity of dimethylbutenes in C 6 olefins = ∼80%). The ratio of DMB-1/TMEN could be controlled without changing the catalytic activities by varying the molar ratios of catalyst precursors. CF 3 SO 3 H was found to be the most effective additive for increasing the reaction rate, although the selectivity of dimethylbutenes decreased significantly. Addition of a small amount of water enhanced the reaction rate significantly (turnover numbers for 2,3-dimethylbutenes: 7046 → 30358). The importance of these catalyst systems should be emphasized, because the amount of nickel species required can be minimized compared with that required for the conventional process.