Organometallic nickel catalysts anchored on polymeric matrices in the oligomerization and/or polymerization of olefins. Part II. Effect and role of the components of the catalytic system

A cationic nickel complex of the bis(8-quinolyl)(3,5-di-tert-butylphenoxy)phosphine (NPN) ligand, [(NPN)NiCl]+, is a precursor to efficient catalysts for the hydrosilation of alkenes with hydrosilanes under mild conditions and low catalyst loadings.

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Synthetical Applications of Activated Metal Catalysts. XVI. The Role of Hydrogen in the Formation of 2,2'-Bipyridyl from Pyridine under the Influence of Degassed Raney Nickel

Australian Journal of Chemistry ◽

10.1071/ch9630014 ◽

1963 ◽

Vol 16 (1) ◽

pp. 14 ◽

Cited By ~ 3

Author(s):

WHF Sasse ◽

CP Whittle

Keyword(s):

Raney Nickel ◽

Nickel Catalysts ◽

Nickel Atom ◽

Metal Catalysts ◽

Published Data ◽

Hydrogen Atoms ◽

Adsorbed Pyridine

The efficiency of W7 Raney nickel catalysts degassed between 30 and 400�C in the preparation of 2,2'-bipyridyl has been examined. The highest activities are observed with catalysts which have been degassed at 200�C, and these catalysts arc up to 20% more efficient than catalysts previously used and degassed at 100�C. The results obtained are compared with published data concerning the hydrogen contents of degassed Raney nickel catalysts (Kokes and Emmett 1959, 1960). This shows that catalysts which are virtually free of hydrogen are only 25% less efficient than catalysts degassed at l00�C (containing 65 to 70% of their original hydrogen). Because of this finding a new mechanism is proposed in which the adsorbed pyridine is activated by the transfer of an electron from the catalyst. On stereochemical grounds it is proposed that meso-2,2'-dihydro-2,2'-bipyridyl with axially disposed hydrogen atoms at the 2,2'-positions and bonded via both nitrogen atoms to one nickel atom is the energetically most favoured intermediate.

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The role of proton-donors in cyclotrimerization of isocyanates by the action of an amine-epoxide catalytic system

Polymer Science U S S R ◽

10.1016/0032-3950(83)90462-8 ◽

1982 ◽

Vol 24 (11) ◽

pp. 2768-2778 ◽

Cited By ~ 2

Author(s):

N.A. Shibanova ◽

A.K. Zhitinkina ◽

L.V. Turetskii ◽

N.V. Varentsova

Keyword(s):

Catalytic System ◽

Proton Donors

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The effect of the components of the PdCl2/Fe/I2/Py catalytic system on nitrobenzene carbonylation to ethyl N-phenylcarbamate

Open Chemistry ◽

10.2478/bf02476235 ◽

2005 ◽

Vol 3 (1) ◽

pp. 28-39 ◽

Cited By ~ 6

Author(s):

Jadwiga Skupińska ◽

Monika Karpińska ◽

Maria Ołówek ◽

Teresa Kasprzycka-Guttman

Keyword(s):

Catalytic System ◽

Considerable Increase ◽

Constant Level ◽

The Other ◽

Reaction Products ◽

Highly Active

AbstractThe PdCl2/Fe/I2/Py catalytic system (Py-pyridine), reported to be highly active in the reaction of nitrobenzene carbonylation to ethyl phenylcarbamate was studied. The present paper describes the role of catalyst components and its effect on the activity and selectivity of the catalyst. The increase in the amount of PdCl2 in the system while retaining a constant level of the other catalyst components, results in the increase of both carbamate and aniline yields. The increase in the amount of iron while retaining the other components constant, initially causes an increase in the carbamate yield; however, at Fe: Pd ratios higher than 36, the carbamate yield remains constant. The change in the amount of iron has no effect on the amount of aniline formed in the system. An increase in the amount of iodine in the system while retaining the other components constant, results in a decrease in carbamate yield and a considerable increase in the aniline yield of the reaction products.

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