Grantee Research Project Results
Final Report: Development of a Heterogeneous Catalyst for Hydroformylation in Supercritical CO2
EPA Grant Number: R828206Title: Development of a Heterogeneous Catalyst for Hydroformylation in Supercritical CO2
Investigators: Abraham, Martin A. , Davies, Julian A. , Mason, Mark R.
Institution: University of Toledo
EPA Project Officer: Hahn, Intaek
Project Period: July 1, 2000 through June 30, 2003 (Extended to June 30, 2004)
Project Amount: $315,000
RFA: Technology for a Sustainable Environment (1999) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities
Objective:
There are currently several paths being investigated for the development of an environmentally friendly hydroformylation process for alkenes greater than C4. Attempts to extend the biphasic process involve the development of new catalysts that have increased solubility in the organic layer or modification of the aqueous layer to enhance the solubility of the alkene. Traditional supported catalysts are being considered for vapor phase hydroformylation, and homogeneous catalysts are being developed for use with scCO2. Our research represents a combination of the latter two routes for hydroformylation that combines the benefits of heterogeneous catalysis with those of supercritical fluid technology. The development of a selective heterogeneous catalyst tailored for use in scCO2 is the fundamental intellectual component of the EPA-funded research program
The heterogeneously catalyzed hydroformylation reaction will only be effective if we can develop a catalyst that is both active and selective. Literature reports provide clues as to which modifications of either the support or the metal catalyst should be helpful in achieving this goal. Towards this end, we established the following specific goals for this research program:
1. Prepare a series of novel rhodium-based catalysts that can define the effects of the catalyst, ligand, and support on the hydroformylation reaction. Supports containing long-chain fluorinated modifiers have been used to modify the local environment around the supported rhodium metal. Mesoporous supports with well-defined and uniform pore sizes were evaluated for their ability to control the selectivity to the normal isomer. Ligand modifiers will also be developed to adjust the selectivity of the reaction.
2. Evaluate these catalysts for their activity and selectivity for the hydroformylation of 1-hexene, chosen as a model of the hydroformylation reaction in general.
3. For a selected group of catalyst samples prepared in Objective 1, evaluate the reaction mechanism using traditional catalyst characterization techniques, including temperature programmed desorption/reaction, metal dispersion and surface area through adsorption, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).
Approach:
This proposal seeks to eliminate potentially hazardous organic solvents through two novel developments:1. Perform the target reaction in the benign reaction solvent supercritical CO2, and
2. Develop a heterogeneous catalyst for the target reaction.
The use of CO2 as a reaction solvent offers optimal environmental performance because CO2 does not deplete the ozone layer, does not contribute to ground-level smog, and will not contribute to global warming. The use of CO2 by-product from existing commercial and natural sources will ensure that no net increase in global CO2 results from the use of this technology.
One limitation of heterogeneous catalysis has been the inability to control selectivity. We believe, however, that modification of the catalyst and the support for optimization with scCO2 can allow the development of active and selective catalysts for the hydroformylation reaction. Use of supported metal-phosphine ligands will allow control of selectivity, similar to that seen in liquid-phase catalysis. Modification of the catalyst support, and the use of shape-selective catalysts with uniform molecular-size pores, provides further opportunity to achieve selectivity control.
Summary/Accomplishments (Outputs/Outcomes):
Rhodium, platinum, and palladium catalysts supported on silica and mesoporous MCM-41 have been prepared and characterized. These materials have been tested for their performance in the hydroformylation of 1-hexene in supercritical CO2. Detailed analysis of the reaction mechanism has also been completed, resulting in a better understanding of the interactions of the supercritical solvent and the heterogenized catalyst. Since much of this work has been published in the open literature, summary statements of the significant accomplishments are provided below, along with the citation to the complete work.
One of the key advances proposed by this research was the development of a catalyst that performed as a homogeneous catalyst but could be immobilized in the reactor as a heterogeneous catalyst. We attempted to accomplish this goal by grafting the homogeneous catalyst onto a solid support and utilizing it in combination with a supercritical fluid to reduce the phase transfer effects that often inhibit the performance of supported catalysts. We demonstrated that the performance of the catalyst could be varied using traditional methods from homogeneous catalysis, heterogeneous catalysis, and reactions in supercritical fluids. Catalyst performance was compared as a function of reaction conditions, and the surface mechanism was probed using high-pressure diffuse reflectance infrared Fourier-transform spectroscopy. The reaction mechanism for hydroformylation of 1-hexene in supercritical CO2 over rhodium catalysts supported on phosphinated silica species was shown to follow a mechanism similar to that known from homogeneous hydroform-ylation, as shown in Figure 1, and described in detail in Ind. Eng. Chem. Res., 2005, 44, 4973-4981.
Figure 1: Mechanism for hydroformylation by supported Rh catalyst in supercritical CO2, as described in Ind. Eng. Chem. Res., 2005, 44, 4973-4981.
Platinum–phosphine complexes anchored on silica and on mesoporous MCM-41 supports were also synthesized and evaluated for hydroformylation activity. Experiments were performed at 100°C in supercritical carbon dioxide (pressure = 2700 psi) using these supported platinum catalysts with SnCl2:2H2O (Sn:Pt = 3.5:1) as co-catalyst. No hydrogenation was observed and high regioselectivity to heptanal was obtained. These results again revealed that the pore size and the high surface area of the MCM-41 support provided high regioselectivity. Surface acidity and interactions with or retention of Sn may be additional parameters contributing to the higher regioselectivity obtained with MCM supports. Details are included in Catalysis Communications, 2003, 4 (7), 309-314.
Finally, asymmetric ligands, specifically (R)-BINAP, have been used to provide an enantioselective product. Rhodium based catalysts were prepared in supercritical carbon dioxide and evaluated for the hydroformylation of styrene to produce 2-phenylpropionaldheyde. The catalyst was formed in situ in supercritical carbon dioxide (scCO2), and was found to promote the hydroformylation of styrene in scCO2 with enantiomeric selectivity when using (R)-BINAP ligands. Details are provided in Ind. Eng. Chem. Res., 2006, 45, 1324-1330.
Expected Results:
The work completed through this research will demonstrate the production of commercially important chemical intermediates without the use of organic solvents. The proposed process considers an environmentally benign synthesis that can be adapted for the production of many important chemicals. These process modifications decrease the potential for volatile organic compounds (VOCs) emission in large-scale production processes, providing one means for the chemical industry to be responsive to pollution prevention requirements.Journal Articles on this Report : 12 Displayed | Download in RIS Format
| Other project views: | All 12 publications | 12 publications in selected types | All 12 journal articles |
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Abraham MA, Nguyen N. “Green engineering: defining the principles”— results from the Sandestin Conference. Environmental Progress & Sustainable Energy 2003;22(4):233-236. |
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Bektesevic S, Tack T, Mason MR, Abraham MA. Analysis of the hydroformylation reaction over an immobilized catalyst in supercritical carbon dioxide. Industrial & Engineering Chemistry Research 2005;44(14):4973-4981. |
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Bektesevic S, Kleman AM, Marteel-Parrish AE, Abraham MA. Hydroformylation in supercritical carbon dioxide: catalysis and benign solvents. The Journal of Supercritical Fluids 2006;38(2):232-241. |
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Hemminger O, Marteel A, Mason MR, Davies JA, Tadd AR, Abraham MA. Hydroformylation of 1-hexene in supercritical carbon dioxide using a heterogeneous rhodium catalyst. 3. Evaluation of solvent effects. Green Chemistry 2002;4(5):507-512. |
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Kleman AM, Abraham MA. Asymmetric hydroformylation of styrene in supercritical carbon dioxide. Industrial & Engineering Chemistry Research 2006;45(4):1324-1330. |
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Marteel AE, Tack TT, Bektesevic S, Davies JA, Mason MR, Abraham MA. Hydroformylation of 1-hexene in supercritical carbon dioxide: characterization, activity, and regioselectivity studies. Environmental Science & Technology 2003;37(23):5424-5431. |
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Marteel AE, Davies JA, Olson WW, Abraham MA. Green chemistry and engineering: drivers, metrics, and reduction to practice. Annual Review of Environment and Resources 2003;28:401-428. |
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Marteel A, Davies JA, Mason MR, Tack T, Bektesevic S, Abraham MA. Supported platinum/tin complexes as catalysts for hydroformylation of 1-hexene in supercritical carbon dioxide. Catalysis Communications 2003;4(7):309-314. |
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Snyder G, Tadd A, Abraham MA. Evaluation of catalyst support effects during rhodium-catalyzed hydroformylation in supercritical CO2. Industrial & Engineering Chemistry Research 2001;40(23):5317-5325. |
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St John Sutton MG, Plappert T, Abraham WT, Smith AL, DeLurgio DB, Leon AR, Loh E, Kocovic DZ, Fisher WG, Ellestad M, Messenger J, Kruger K, Hilpisch KE, Hill MRS, Multicenter InSync Randomized Clinical Evaluation (MIRACLE) Study Group. Effect of cardiac resynchronization therapy on left ventricular size and function in chronic heart failure. Circulation 2003;107(15):1985-1990. |
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Tadd AR, Marteel A, Mason MR, Davies JA, Abraham MA. Hydroformylation of 1-hexene in supercritical carbon dioxide using a heterogeneous rhodium catalyst. 2. Evaluation of reaction kinetics. Industrial & Engineering Chemistry Research 2002;41(18):4514-4522. |
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Tadd AR, Marteel A, Mason MR, Davies JA, Abraham MA. Hydroformylation of 1-hexene in supercritical carbon dioxide using a heterogeneous rhodium catalyst. 1. Effect of process parameters. The Journal of Supercritical Fluids 2003;25(2):183-196. |
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Supplemental Keywords:
Green chemistry, clean technologies, benign solvent, supercritical CO2, heterogeneous catalyst, mesoporous supports.
, Sustainable Industry/Business, RFA, Scientific Discipline, Air, Technology for Sustainable Environment, Chemical Engineering, Sustainable Environment, Environmental Chemistry, tropospheric ozone, Economics and Business, cleaner production/pollution prevention, climate change, environmentally-friendly chemical synthesis, source reduction, liquid organic solvents, air quality, alternative chemical synthesis, pollution prevention, atmospheric pollutant loads, environmentally benign catalysts, supercritical carbon dioxide, global warming, environmental monitoring, CO2 - based systems, climate variability, green house gas concentrations, hydroformation reaction, sustainable development, chemical reaction systems, cleaner production, green process systems, ambient air pollution, ambient air, VOCs, environmentally benign solvents, hazardous organic solvents, Volatile Organic Compounds (VOCs), alternative solvents, green chemistry, homogeneous catalysis, solvent substitute
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.