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Title: LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).

Abstract

The overall purpose of this LDRD is multifold. First, we are interested in preparing new homogeneous catalysts that can be used in the oligomerization of ethylene and in understanding commercially important systems better. Second, we are interested in attempting to support these new homogeneous catalysts in the pores of nano- or mesoporous materials in order to force new and unusual distributions of a-olefins to be formed during the oligomerization. Thus the overall purpose is to try to prepare new catalytic species and to possibly control the active site architecture in order to yield certain desired products during a catalytic reaction, much like nature does with enzymes. In order to rationally synthesize catalysts it is imperative to comprehend the function of the various components of the catalyst. In heterogeneous systems, it is of utmost importance to know how a support interacts with the active site of the catalyst. In fact, in the catalysis world this lack of fundamental understanding of the relationship between active site and support is the single largest reason catalysis is considered an 'empirical' or 'black box' science rather than a well-understood one. In this work we will be preparing novel ethylene oligomerization catalysts, which are normally P-Omore » chelated homogeneous complexes, with new ligands that replace P with a stable carbene. We will also examine a commercially catalyst system and investigate the active site in it via X-ray crystallography. We will also attempt to support these materials inside the pores of nano- and mesoporous materials. Essentially, we will be tailoring the size and scale of the catalyst active site and its surrounding environment to match the size of the molecular product(s) we wish to make. The overall purpose of the study will be to prepare new homogeneous catalysts, and if successful in supporting them to examine the effects that steric constraints and pore structures can have on growing oligomer chains.« less

Authors:
;
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
920453
Report Number(s):
SAND2004-5506
TRN: US200818%%21
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HOMOGENEOUS CATALYSIS; CATALYSTS; CRYSTALLOGRAPHY; ETHYLENE; POLYMERIZATION; PORE STRUCTURE; CATALYST SUPPORTS; POROUS MATERIALS; SYNTHESIS; Catalysts-Analysis.; Oligomers.; Nanoscience.

Citation Formats

Hascall, Anthony G., and Kemp, Richard Alan. LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).. United States: N. p., 2004. Web. doi:10.2172/920453.
Hascall, Anthony G., & Kemp, Richard Alan. LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).. United States. doi:10.2172/920453.
Hascall, Anthony G., and Kemp, Richard Alan. Mon . "LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).". United States. doi:10.2172/920453. https://www.osti.gov/servlets/purl/920453.
@article{osti_920453,
title = {LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).},
author = {Hascall, Anthony G. and Kemp, Richard Alan},
abstractNote = {The overall purpose of this LDRD is multifold. First, we are interested in preparing new homogeneous catalysts that can be used in the oligomerization of ethylene and in understanding commercially important systems better. Second, we are interested in attempting to support these new homogeneous catalysts in the pores of nano- or mesoporous materials in order to force new and unusual distributions of a-olefins to be formed during the oligomerization. Thus the overall purpose is to try to prepare new catalytic species and to possibly control the active site architecture in order to yield certain desired products during a catalytic reaction, much like nature does with enzymes. In order to rationally synthesize catalysts it is imperative to comprehend the function of the various components of the catalyst. In heterogeneous systems, it is of utmost importance to know how a support interacts with the active site of the catalyst. In fact, in the catalysis world this lack of fundamental understanding of the relationship between active site and support is the single largest reason catalysis is considered an 'empirical' or 'black box' science rather than a well-understood one. In this work we will be preparing novel ethylene oligomerization catalysts, which are normally P-O chelated homogeneous complexes, with new ligands that replace P with a stable carbene. We will also examine a commercially catalyst system and investigate the active site in it via X-ray crystallography. We will also attempt to support these materials inside the pores of nano- and mesoporous materials. Essentially, we will be tailoring the size and scale of the catalyst active site and its surrounding environment to match the size of the molecular product(s) we wish to make. The overall purpose of the study will be to prepare new homogeneous catalysts, and if successful in supporting them to examine the effects that steric constraints and pore structures can have on growing oligomer chains.},
doi = {10.2172/920453},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Nov 01 00:00:00 EST 2004},
month = {Mon Nov 01 00:00:00 EST 2004}
}

Technical Report:

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  • This report summarizes our findings during the study of a novel homogeneous epoxidation catalyst system that uses molecular oxygen as the oxidant, a ''Holy Grail'' in catalysis. While olefins (alkenes) that do not contain allylic hydrogens can be epoxidized directly using heterogeneous catalysts, most olefins cannot, and so a general, atom-efficient route is desired. While most of the work performed on this LDRD has been on pincer complexes of late transition metals, we also scouted out metal/ligand combinations that were significantly different, and unfortunately, less successful. Most of the work reported here deals with phosphorus-ligated Pd hydrides [(PCP)Pd-H]. We havemore » demonstrated that molecular oxygen gas can insert into the Pd-H bond, giving a structurally characterized Pd-OOH species. This species reacts with oxygen acceptors such as olefins to donate an oxygen atom, although in various levels of selectivity, and to generate a [(PCP)Pd-OH] molecule. We discovered that the active [(PCP)Pd-H] active catalyst can be regenerated by addition of either CO or hydrogen. The demonstration of each step of the catalytic cycle is quite significant. Extensions to the pincer-Pd chemistry by attaching a fluorinated tail to the pincer designed to be used in solvents with higher oxygen solubilities are also presented.« less
  • Alumina-supported cobalt-molybdenum catalysts were prepared from cobalt and molybdenum carbonyls and characterized by x-ray photoelectron spectroscopy, ion-scattering spectrometry, x-ray powder diffractometry and Raman spectroscopy.
  • The synthesis of two series of supported metal catalysts has been achieved. The first series consisted of iron on the oxide supports, MgO, ZnO, TiO/sub 2/, Al/sub 2/O/sub 3/, SiO/sub 2/ and ThO/sub 2/; the second comprised iron, cobalt and iron/cobalt mixtures on the zeolite supports ZSM-5, NU-1, mordenite and 13X. All potentially active catalytic materials were prepared by techniques developed in our laboratory during the previous contract period using metal carbonyls as the source of the metal component; metal loadings ranged between 1 and 20%. Characterization of some of the materials was achieved by using the techniques of x-raymore » powder diffraction, ion-scattering spectrometry, secondary ion mass spectroscopy, electron spectroscopy for chemical analysis, scanning electron microscopy, Moessbauer spectroscopy and thermogravimatric analysis. Evaluation of the catalytic ability of some of the materials for the hydrogenation of carbon monoxide was conducted.« less
  • The synthesis of tetrachlorotetraphenylcyclopentadienyl group 5 metal complexes has been accomplished through two routes, one a salt metathesis with lithiumtetraphenylcyclopentadiende and the other, reaction with trimethyltintetraphenylcyclopentadiene. The reactants and products have been characterized by {sup 1}H and {sup 13}C({sup 1}H) NMR spectroscopy. The niobium complex promotes the silylcyanation of butyraldehyde. The grafting of metal complexes to silica gel surfaces has been accomplished using tetrakisdimethylamidozirconium as the metal precursor. The most homogeneous binding as determined by CP-MAS {sup 13}C NMR and infrared spectroscopy was obtained with drying at 500 C at 3 mtorr vacuum. The remaining amido groups can be replacedmore » by reaction with alcohols to generate surface bound metal alkoxides. These bound catalysts promote silylcyanation of aryl aldehydes and can be reused three times with no loss of activity.« less
  • The LDRD project 'A New Method for Wave Propagation in Elastic Media' developed several improvements to the traditional finite difference technique for seismic wave propagation, including a summation-by-parts discretization which is provably stable for arbitrary heterogeneous materials, an accurate treatment of non-planar topography, local mesh refinement, and stable outflow boundary conditions. This project also implemented these techniques in a parallel open source computer code called WPP, and participated in several seismic modeling efforts to simulate ground motion due to earthquakes in Northern California. This research has been documented in six individual publications which are summarized in this report. Of thesemore » publications, four are published refereed journal articles, one is an accepted refereed journal article which has not yet been published, and one is a non-refereed software manual. The report concludes with a discussion of future research directions and exit plan.« less