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Title: Catalyst system comprising a first catalyst system tethered to a supported catalyst

Abstract

The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.

Inventors:
;
Publication Date:
Research Org.:
Iowa State University
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
672674
Patent Number(s):
US 5,789,333/A/
Application Number:
PAN: 8-811,426
Assignee:
Iowa State Univ. Research Foundation, Inc., Ames, IA (United States) PTO; SCA: 400201; PA: EDB-98:120384; SN: 98002026910
DOE Contract Number:
W-7405-ENG-82
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 4 Aug 1998
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; CATALYST SUPPORTS; CATALYSTS; SERVICE LIFE; HYDROGENATION; ALKENES; RECYCLING

Citation Formats

Angelici, R.J., and Gao, H. Catalyst system comprising a first catalyst system tethered to a supported catalyst. United States: N. p., 1998. Web.
Angelici, R.J., & Gao, H. Catalyst system comprising a first catalyst system tethered to a supported catalyst. United States.
Angelici, R.J., and Gao, H. 1998. "Catalyst system comprising a first catalyst system tethered to a supported catalyst". United States. doi:.
@article{osti_672674,
title = {Catalyst system comprising a first catalyst system tethered to a supported catalyst},
author = {Angelici, R.J. and Gao, H.},
abstractNote = {The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1998,
month = 8
}
  • The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systemsmore » very economical.« less
  • This paper describes a catalyst composition. It comprises: essentially of a high density support of co-precipitated titania and zirconia of compacted bulk density of 0.8-1.2 g/cc, a pore volume of 0.4-0.8 cc/g and a specific surface area by nitrogen BET of grater than 250 to about 400m{sup 2}/g, having associated therewith from 1-30 percent by weight of molybdenum oxide and 1-10 percent by weight of at least one member selected from the group consisting of nickel oxide and cobalt oxide, and, optionally, .08-6.8 percent, by weight phosphorus.
  • In a method for removing pollutants from the exhaust gas of an internal combustion engine, fuel is burned in the engine at a substantially less than stoichiometric air-fuel ratio during cold engine operation and at a greater but substoichiometric air-fuel ratio during warm engine operation. The exhaust gas is contacted under net reducing conditions with a nitrogen oxide reduction catalyst in a first conversion zone and is then treated with added secondary air under net oxidizing conditions in a second conversion zone to oxidize carbon monoxide and hydrocarbons. A quantity of primary air not greater than stoichiometric is supplied tomore » the first conversion zone, and a quantity of secondary air at least stoichiometrically equivalent to the amount of CO present is supplied to the second conversion zone, with the primary air being supplied during cold engine operation and the secondary air being supplied at all times during operation of the engine. The supply of primary air is shut off when the average air-fuel ratio reaches substantially its normal warm engine value.« less
  • The C-F bond, which is the strongest bond that carbon can form, is extremely reluctant to coordinate to metal centers and is resistant to chemical attack. Although this lack of fluorocarbon reactivity has frequently been exploited in technological and medical applications, this chemical inertness also translates into environmental persistence since these compounds are quite difficult to degrade. Fluorobenzene and 1,2-difluorobenzene are defluorinated under very mild conditions by H{sub 2}(4 atm) at 70 C in the presence of NaOAc. The heterogeneous catalysts for these reactions contain the rhodium pyridylphosphine and bipyridyl complexes tethered to heterogeneous Pd-SiO{sub 2}.