27 Matching Results

Search Results

Advanced search parameters have been applied.

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

Description: An investigation aimed at devising a procedure for preparing alkyl-or aryl-capped iron sulfide particles continues. An initial attempt to prepare fine-particle, aryl-capped iron sulfides (S-31) involved the competitive reaction of thiophenol (PhSH) and sodium sulfide (Na{sub 2}S) with Fe(II). However, SEM examination of the particles formed by this procedure indicated that no size control had been attained. It was thought that the phenyl group of thiophenol was not bulky enough to prevent thiolate bridging and consequent particle size growth of the metal sulfide. So the bulkier thiol 1-adamantanethiol was synthesized and used in synthesis S-33 in the next attempt to prepare fine-particle, capped iron sulfides.
Date: May 22, 1992
Creator: Klein, M.T.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: As specified in our original DOE grant proposal, the objective of this research is to design a new alumina-supported bimetallic catalyst for the selective hydrogenation of carbon monoxide to produce methanol and higher alcohols. A key feature of our research program is our intention to rationally design this catalyst based upon fundamental information about the structure, composition and reactivity of preliminary catalysts synthesized throughout the course of this work. During our first year, we have put in place many of the tools needed to synthesize and characterize our catalyst samples. Experimentation has focused on both the synthesis of catalysts designed for high oxygenate activity and the suppression of the secondary dehydration of methanol to dimethyl ether on both native gamma-alumina and a bimetallic catalyst supported on gamma-alumina. 2 refs., 1 tab.
Date: September 27, 1991
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Short contact time direct coal liquefaction using a novel batch reactor. Quarterly report, May 15, 1995--September 15, 1995

Description: The objective of this research is to optimize the design and operation of the bench scale batch reactor for coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction, particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. This quarterly report covers the status of progress toward these objectives. 3 refs., 14 figs., 2 tabs.
Date: October 5, 1995
Creator: Klein, M.T.; Calkins, W.H. & Huang, He
Partner: UNT Libraries Government Documents Department

Short contact time direct coal liquefaction using a novel batch reactor. Quarterly progress report, January 1--May 15, 1995

Description: The objective of this research is to optimize the design and operation of the bench scale batch reactor for coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. Experimental progress is reported for uncatalyzed liquefactions, catalyzed liquefactions, liquefaction in the presence of solvents other than tetralin, and kinetics of gas formation during coal liquefaction. Analytical methods were developed for the determination of the boiling range of coal liquids by thermogravimetric analysis and the determination of phenolic hydroxyl in coal, coal liquids, and coal residues.
Date: May 31, 1995
Creator: Klein, M.T. & Calkins, W.H.
Partner: UNT Libraries Government Documents Department

Low temperature SO sub 2 removal with solid sorbents in a Circulating Fluidized Bed Absorber

Description: The construction of a bench-scale Circulating Fluidized Bed Absorber (CFBA) unit has been completed, and system calibrations have already been performed. In addition, as a novel method injecting water into CFBA, a toroidal-shaped nozzle was designed and installed in a bed reactor to increase the wetting efficiency of solid sorbents. The experimental set up for low temperature SO{sub 2} removal consists of a bed reactor of 3 inches in diameter and 10 feet in length, two high efficiency cyclones for gas/solid separation, sorbent injection and recycling system, water injection system, gas heating system, and gas flow, concentration, temperature and pressure monitoring system. The toroidal shaped nozzle located at the base of the bed has 12 holes placed symmetrically around the ring at an angle of 50{degrees} with the horizontal, and is made of copper tube.
Date: January 1, 1992
Creator: Lee, S.K. & Keener, T.C.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

Description: The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.
Date: February 22, 1991
Creator: Klein, M.T.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

Description: A series of carbonyl-based homogeneous catalyst precursors has been prepared. These species include: Fe(CO){sub 4}PPh{sub 3}, Fe(CO){sub 3}(PPh{sub 3}){sub 2}, Fe(CO){sub 2}(PPh{sub 3}){sub 2}CS{sub 2}, S{sub 2}Fe{sub 2}(CO){sub 6}, S{sub 2}Fe{sub 3}(CO){sub 9}. Fe(CO){sub 4}PPh{sub 3} was prepared by a combined photochemical and thermal route from triphenylphosphine (PPh{sub 3}) in iron pentacarbonyl (Fe(CO){sub 5}). This preparation procedure, which is selective to the monosubstituted product, is outlined herein. Currently these compounds are being tested as catalysts/catalyst precursors with coal or model compounds in the tubing bomb reactors to provide information relating catalytic activity to catalyst structure and properties. (VC)
Date: September 11, 1991
Creator: Klein, M.T.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

Description: The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.
Date: December 30, 1991
Creator: Klein, M.T.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Seventh quarterly report, February 7, 1992--May 7, 1992

Description: In order to explore the secondary dehydration of methanol over {gamma}-Al{sub 2}O{sub 3} support and over bimetallic Rh-Mo/{gamma}- Al{sub 2}O{sub 3}, a new series of K-doped Rh-Mo/{gamma}-Al{sub 2}O{sub 3} catalysts was synthesized. Work on synthesis of bimetallic Rh-Mo clusters is reported.
Date: June 4, 1992
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Eleventh quarterly report, February 7, 1993--May 7, 1993

Description: The apparatus used for ammonia saturation and TPD (=temperature programmed desorption?) testing was modified to avoid repeated injections of NH{sub 3}. Saturation and TPD results are presented for potassium-doped {gamma}-alumina. In order to examine effects of Mo oxide promotion on catalytic activity of alumina-supported Rh catalyst, additional samples of Rh/{gamma}-Al{sub 2}O{sub 3} and Rh-Mo/{gamma}-Al{sub 2}O{sub 3} have been synthesized. 2 tabs, 3 figs.
Date: September 2, 1993
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Sixth quarterly report, November 7, 1991--February 7, 1992

Description: Results of the pyridine adsorption, studies on native and K-doped alumina provide fundamental grounding for the observed methanol dehydration activity of these samples. Both the reactor studies and the pyridine adsorption studies support the conclusion that the K-doped sample had reduced Lewis acidity. Moreover, we were able to measurably alter the acidity of the support surface by our ion exchange treatment. More significantly, when reactor results for transition-metal loaded samples are reconsidered in combination with their surface characteristics suggested by our pyridine adsorption studies, our hypothesis that Rh and Mo have ultimately titrated the support surface seems all the more convincing. Hence, in light of the pyridine adsorption results, the attenuation of a transition-metal based decomposition pathway for methanol on the metal-loaded samples-as seen in the reactor testing-is all the more reasonable.
Date: February 7, 1992
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: Efforts to synthesize bimetallic cluster-derived Rh-Mo catalysts for CO and CO[sub 2] hydrogenation to preferentially produce oxygenates. The rhodium-molybdenum cluster, (PPh[sub 3])[sub 2]RhMO(CO)([mu]-CO)[sub 2]Cp, was employed as a precursor to alumina- and silica-supported catalysts which were in CO hydrogenation. When compared to catalysts made from the distinct organometallic complexes, RhH(CO)(PPh[sub 3])[sub 3] and [MO(CO)[sub 3]Cp][sub 2], the catalysts derived from a binuclear precursor show higher activities for CO hydrogenation and superior selectivities towards oxygenates, namely, methanol, dimethyl ether and ethanol. Their product distributions depend on the support. Fourier transform infrared spectroscopy studies indicate that CO chemisorbs on cluster-derived catalysts as gem-dicarbonyls while it is chemisorbed only in the linear-carbonyl configuration on catalysts made from separate rhodium and molybdenum complexes. The particular oxygenate selectivity of the cluster-derived catalysts may be correlated to the strong electronic interaction between Rh and Mo. Carbon dioxide hydrogenation has also been carried out on the catalysts mentioned above. Again, the cluster-derived catalysts show higher oxygenate selectivities. Finally, the catalysts were studied with regard to both CO and CO[sub 2] hydrogenation kinetics, apparent activation energies inferred.
Date: November 30, 1992
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: Preliminary investigations of these manganese oxide materials show that the different oxides exhibit different selectivity toward methanol and other products. It seems that there is a correlation between the initial O/Mn ratio of the oxide and methanol selectivity. These conclusions are supported by the results displayed in Figures 1 and 2. The main product of the manganese oxide-catalyzed CO hydrogenation is methanol except on Mao, which shows the lowest methanol selectivity, but the highest CO[sub 2] yield. Preliminarily, the results suggest that the higher the O/Mn ratio of the precursor oxide, the higher will be the methanol selectivity, while the CO[sub 2] and methane selectivities will be lower. The higher CO[sub 2] and C[sub 2], C[sub 3] and C[sub 4] hydrocarbon selectivities over the Mao catalyst compared to the other manganese oxides tested, indicates that Mao acts more like a water-gas shift and Fischer-Tropsch catalyst.
Date: February 17, 1993
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: Results of the pyridine adsorption, studies on native and K-doped alumina provide fundamental grounding for the observed methanol dehydration activity of these samples. Both the reactor studies and the pyridine adsorption studies support the conclusion that the K-doped sample had reduced Lewis acidity. Moreover, we were able to measurably alter the acidity of the support surface by our ion exchange treatment. More significantly, when reactor results for transition-metal loaded samples are reconsidered in combination with their surface characteristics suggested by our pyridine adsorption studies, our hypothesis that Rh and Mo have ultimately titrated the support surface seems all the more convincing. Hence, in light of the pyridine adsorption results, the attenuation of a transition-metal based decomposition pathway for methanol on the metal-loaded samples-as seen in the reactor testing-is all the more reasonable.
Date: February 7, 1992
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: In methanol dehydration by K-doped Rh-Mo/[gamma]-Al[sub 2]O[sub 3], while higher K levels reduced the dehydration propensity of the surface, at higher levels the potassium oxide layer formed after doping and calcining the surface interferes detrimentally with the Rh-Mo active metallic sites. Silica- and alumina-supported catalysts with 0.5% Rh loading were synthesized and tested for hydrogenation of CO.
Date: July 30, 1992
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst

Description: In order to explore the secondary dehydration of methanol over [gamma]-Al[sub 2]O[sub 3] support and over bimetallic Rh-Mo/[gamma]- Al[sub 2]O[sub 3], a new series of K-doped Rh-Mo/[gamma]-Al[sub 2]O[sub 3] catalysts was synthesized. Work on synthesis of bimetallic Rh-Mo clusters is reported.
Date: June 4, 1992
Creator: Foley, H.C. & Mills, G.A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Ninth quarterly report, August 7, 1992--November 7, 1992

Description: Efforts to synthesize bimetallic cluster-derived Rh-Mo catalysts for CO and CO{sub 2} hydrogenation to preferentially produce oxygenates. The rhodium-molybdenum cluster, (PPh{sub 3}){sub 2}RhMO(CO)({mu}-CO){sub 2}Cp, was employed as a precursor to alumina- and silica-supported catalysts which were in CO hydrogenation. When compared to catalysts made from the distinct organometallic complexes, RhH(CO)(PPh{sub 3}){sub 3} and [MO(CO){sub 3}Cp]{sub 2}, the catalysts derived from a binuclear precursor show higher activities for CO hydrogenation and superior selectivities towards oxygenates, namely, methanol, dimethyl ether and ethanol. Their product distributions depend on the support. Fourier transform infrared spectroscopy studies indicate that CO chemisorbs on cluster-derived catalysts as gem-dicarbonyls while it is chemisorbed only in the linear-carbonyl configuration on catalysts made from separate rhodium and molybdenum complexes. The particular oxygenate selectivity of the cluster-derived catalysts may be correlated to the strong electronic interaction between Rh and Mo. Carbon dioxide hydrogenation has also been carried out on the catalysts mentioned above. Again, the cluster-derived catalysts show higher oxygenate selectivities. Finally, the catalysts were studied with regard to both CO and CO{sub 2} hydrogenation kinetics, apparent activation energies inferred.
Date: November 30, 1992
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Eighth quarterly report, May 7, 1992--August 7, 1992

Description: In methanol dehydration by K-doped Rh-Mo/{gamma}-Al{sub 2}O{sub 3}, while higher K levels reduced the dehydration propensity of the surface, at higher levels the potassium oxide layer formed after doping and calcining the surface interferes detrimentally with the Rh-Mo active metallic sites. Silica- and alumina-supported catalysts with 0.5% Rh loading were synthesized and tested for hydrogenation of CO.
Date: July 30, 1992
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design of a high activity and selectivity alcohol catalyst. Tenth quarterly report, November 7, 1992--February 7, 1993

Description: Preliminary investigations of these manganese oxide materials show that the different oxides exhibit different selectivity toward methanol and other products. It seems that there is a correlation between the initial O/Mn ratio of the oxide and methanol selectivity. These conclusions are supported by the results displayed in Figures 1 and 2. The main product of the manganese oxide-catalyzed CO hydrogenation is methanol except on Mao, which shows the lowest methanol selectivity, but the highest CO{sub 2} yield. Preliminarily, the results suggest that the higher the O/Mn ratio of the precursor oxide, the higher will be the methanol selectivity, while the CO{sub 2} and methane selectivities will be lower. The higher CO{sub 2} and C{sub 2}, C{sub 3} and C{sub 4} hydrocarbon selectivities over the Mao catalyst compared to the other manganese oxides tested, indicates that Mao acts more like a water-gas shift and Fischer-Tropsch catalyst.
Date: February 17, 1993
Creator: Foley, H. C. & Mills, G. A.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, January 26, 1992--April 25, 1992

Description: An investigation aimed at devising a procedure for preparing alkyl-or aryl-capped iron sulfide particles continues. An initial attempt to prepare fine-particle, aryl-capped iron sulfides (S-31) involved the competitive reaction of thiophenol (PhSH) and sodium sulfide (Na{sub 2}S) with Fe(II). However, SEM examination of the particles formed by this procedure indicated that no size control had been attained. It was thought that the phenyl group of thiophenol was not bulky enough to prevent thiolate bridging and consequent particle size growth of the metal sulfide. So the bulkier thiol 1-adamantanethiol was synthesized and used in synthesis S-33 in the next attempt to prepare fine-particle, capped iron sulfides.
Date: May 22, 1992
Creator: Klein, M. T.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 25, 1990--October 24, 1991: Draft

Description: The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.
Date: December 30, 1991
Creator: Klein, M. T.
Partner: UNT Libraries Government Documents Department

Low temperature SO{sub 2} removal with solid sorbents in a Circulating Fluidized Bed Absorber. Quarterly report, March 1992

Description: The construction of a bench-scale Circulating Fluidized Bed Absorber (CFBA) unit has been completed, and system calibrations have already been performed. In addition, as a novel method injecting water into CFBA, a toroidal-shaped nozzle was designed and installed in a bed reactor to increase the wetting efficiency of solid sorbents. The experimental set up for low temperature SO{sub 2} removal consists of a bed reactor of 3 inches in diameter and 10 feet in length, two high efficiency cyclones for gas/solid separation, sorbent injection and recycling system, water injection system, gas heating system, and gas flow, concentration, temperature and pressure monitoring system. The toroidal shaped nozzle located at the base of the bed has 12 holes placed symmetrically around the ring at an angle of 50{degrees} with the horizontal, and is made of copper tube.
Date: July 1, 1992
Creator: Lee, S. K. & Keener, T. C.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 26, 1990--January 26, 1991: Draft

Description: The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.
Date: February 22, 1991
Creator: Klein, M. T.
Partner: UNT Libraries Government Documents Department

Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, April 26, 1991--July 26, 1991: Draft

Description: A series of carbonyl-based homogeneous catalyst precursors has been prepared. These species include: Fe(CO){sub 4}PPh{sub 3}, Fe(CO){sub 3}(PPh{sub 3}){sub 2}, Fe(CO){sub 2}(PPh{sub 3}){sub 2}CS{sub 2}, S{sub 2}Fe{sub 2}(CO){sub 6}, S{sub 2}Fe{sub 3}(CO){sub 9}. Fe(CO){sub 4}PPh{sub 3} was prepared by a combined photochemical and thermal route from triphenylphosphine (PPh{sub 3}) in iron pentacarbonyl (Fe(CO){sub 5}). This preparation procedure, which is selective to the monosubstituted product, is outlined herein. Currently these compounds are being tested as catalysts/catalyst precursors with coal or model compounds in the tubing bomb reactors to provide information relating catalytic activity to catalyst structure and properties. (VC)
Date: September 11, 1991
Creator: Klein, M. T.
Partner: UNT Libraries Government Documents Department