ChemInform Abstract: INVESTIGATIONS OF OLEFIN HYDROGENATION CATALYSTS. THE MAJOR SPECIES PRESENT IN SOLUTIONS CONTAINING RHODIUM(I) COMPLEXES OF CHELATING DIPHOSPHINES

1978 ◽  
Vol 9 (19) ◽  
Author(s):  
D. A. SLACK ◽  
M. C. BAIRD
Keyword(s):  
Olefin Hydrogenation ◽  
Hydrogenation Catalysts ◽  
Major Species

Rh2Cl2(CO)4 adsorbed and tethered on gold powder: IR spectroscopic characterization and olefin hydrogenation activity

2001 ◽  
Vol 79 (5-6) ◽  
pp. 578-586 ◽  
Author(s):  
Hanrong Gao ◽  
Robert J Angelici
Keyword(s):  
Spectroscopic Characterization ◽  
Rhodium Complexes ◽  
Olefin Hydrogenation ◽  
Hydrogenation Catalysts ◽  
Gold Powder ◽  
Ir Studies ◽  
Major Species ◽  
Catalytically Active ◽  
Unidentified Species ◽  
Diffuse Reflectance Infrared

Catalysts were prepared by adsorbing Rh2Cl2(CO)4 directly on gold powder or on gold that contained the tethered ligands 2-(diphenylphosphino)ethane-1-thiol (DPET) or methyl 2-mercaptonicotinate (MMNT). Infrared (IR) studies (diffuse reflectance infrared Fourier transform (DRIFT)) of the catalyst Rh–Au prepared by adsorbing Rh2Cl2(CO)4 directly on Au indicate that a RhI(CO)2 species is present. IR studies of Rh–DPET-Au suggest that tethered cis-Rh(DPET)(CO)2Cl is the major species at relatively high Rh2Cl2(CO)4 loadings, but trans-Rh(DPET)2(CO)Cl is observable at low Rh2Cl2(CO)4 loadings. Spectral investigations of the catalyst Rh–MMNT-Au prepared by adsorbing Rh2Cl2(CO)4 on MMNT-Au suggest that tethered [cis-Rh(MMNT)2(CO)2]+Cl– and (or) Rh(MMNT)(CO)2Cl are the major species at low Rh2Cl2(CO)4 loadings, while a new unidentified species predominates at high Rh2Cl2(CO)4 loadings. All three catalysts are active 1-hexene hydrogenation catalysts under the mild conditions of 40°C and 1 atm of H2; they are much more active than Au powder or Rh2Cl2(CO)4 in solution. Of the three catalysts, Rh–Au is the most active with a maximum turnover frequency (TOF) of 800 mol H2 per mol Rh per min while its turnover (TO) is 29 600 mol H2 per mol Rh during a 2-hour run. Under the conditions of 1-hexene hydrogenation, the catalysts lose their CO ligands. Thus, it appears that a form of Rh metal on Au is the catalytically active species.Key words: catalysis, olefin hydrogenation, gold powder, tethered rhodium complexes, infrared studies, adsorption, rhodium complexes.

EXAFS STUDY OF NICKEL AND IRON PRECURSORS OF HOMOGENEOUS ZIEGLER-TYPE HYDROGENATION CATALYSTS

1986 ◽  
Vol 47 (C8) ◽  
pp. C8-243-C8-248 ◽  
Author(s):  
C. ESSELIN ◽  
E. BAUER-GROSSE ◽  
J. GOULON ◽  
C. WILLIAMS ◽  
Y. CHAUVIN ◽  
...  
Keyword(s):  
Hydrogenation Catalysts ◽  
Exafs Study

Reaction Mechanisms of Inorganic and Organometallic Systems

2007 ◽  
Author(s):  
Robert B. Jordan
Keyword(s):  
Electron Transfer ◽  
Heterogeneous Systems ◽  
Asymmetric Hydrogenation ◽  
Pressure Effects ◽  
General Level ◽  
Hydrogenation Catalysts ◽  
Methyl Transferase ◽  
Transfer Region ◽  
Previous Edition ◽  
Oxide Synthase

This third edition retains the general level and scope of earlier editions, but has been substantially updated with over 900 new references covering the literature through 2005, and 140 more pages of text than the previous edition. In addition to the general updating of materials, there is new or greatly expanded coverage of topics such as Curtin-Hammett conditions, pressure effects, metal hydrides and asymmetric hydrogenation catalysts, the inverted electron-transfer region, intervalence electron transfer, photochemistry of metal carbonyls, methyl transferase and nitric oxide synthase. The new chapter on heterogeneous systems introduces the basic background to this industrially important area. The emphasis is on inorganic examples of gas/liquid and gas/liquid/solid systems and methods of determining heterogeneity.

scholarly journals Development and Application of Efficient Ag‐based Hydrogenation Catalysts Prepared from Rice Husk Waste

ChemCatChem ◽  
2021 ◽  
Author(s):  
Felix Unglaube ◽  
Carsten Robert Kreyenschulte ◽  
Esteban Mejía
Keyword(s):  
Rice Husk ◽  
Hydrogenation Catalysts

Intensification and optimisation of nickel recovery from spent hydrogenation catalysts via ultrasound-augmented hydrometallurgy

2021 ◽  
pp. 105771
Author(s):  
Mitchell S.W. Lim ◽  
Thomas C.K. Yang ◽  
Yeow Hong Yap ◽  
Guan-Ting Pan ◽  
Siewhui Chong ◽  
...  
Keyword(s):  
Hydrogenation Catalysts ◽  
Nickel Recovery

Odontopleura (Trilobita, Silurian), and a method of constrained congruency analysis

1990 ◽  
Vol 64 (4) ◽  
pp. 600-614 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Brian D. E. Chatterton
Keyword(s):  
Cladistic Analysis ◽  
Canadian Arctic ◽  
Wide Distribution ◽  
Parsimony Analysis ◽  
Directed Tree ◽  
Shelf Slope ◽  
Major Species ◽  
Species Groups ◽  
The Universe ◽  
A New Species

Odontopleura (Odontopleura) arctica, a new species of odontopleurine trilobite, is described from the Canadian Arctic. A method of cladistic analysis is detailed. Parsimony analysis should be performed treating all characters as unordered. The universe of directed trees implied by the resulting rootless network(s) can then be examined and a preferred tree selected by a criterion of congruency. Namely, the most parsimonious directed tree that accommodates the most congruent arrangement of character-states should be taken as the preferred cladogram. Since this is essentially a general congruency method operating within the constraints of parsimony, it is termed “constrained congruency.” The method is applied to the genus Odontopleura, resulting in the recognition of two major species groups, the nominate subgenus and Sinespinaspis n. subgen. Odontopleura (Ivanopleura) dufrenoyi Barrande is tentatively included in the genus, but considered too poorly known for cladistic analysis. Species assigned to Odontopleura (Odontopleura) include Odontopleura ovata Emmrich, Odontopleura brevigena Chatterton and Perry, Odontopleura (Odontopleura) arctica n. sp., and Diacanthaspis serotina Apollonov. Species assigned to Sinespinaspis n. subgen. include Taemasaspis llandoveryana Šnajdr, Odontopleura greenwoodi Chatterton and Perry, Odontopleura maccallai Chatterton and Perry, and Odontopleura nehedensis Chatterton and Perry. Odontopleura bombini Chatterton and Perry is tentatively placed in synonymy with Odontopleura nehedensis. The genus had a wide distribution throughout the Early and Middle Silurian, due to preferences for deep-water, distal shelf or shelf-slope transition zone habitats.

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