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Molecular accessibility in oxidized and dried coals. Quarterly report, January 1995--March 1995

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: March 1, 1995
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture los both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution swelled, {ital oxidized} APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering process. This quarter we have continued to examine the effect of exposure of light before alkylation versus after O-alkylation of the coal structure. The variation in uptake of spin probe VII (amine group) is depicted in figure 1 for Wyodak-Anderson. Before O-alkylation, a significant decrease occurred in the uptake of VII with increasing exposure to ambient light. This suggests that partial break-up of the hydrogen bond network occurs, making it possible to wash out more of the spin probes. This effect was eliminated if the coal was O-alkylated after exposure to sunlight (Figure 2). The removal of the source of hydrogen bonding is responsible for the lack of spin probe up-take variation with time of exposure to light. Further experiments have shown that the data in Figures 1 and 2 is reproducible with a deviation of less than {+-} 10%. It has also been observed that ...
Date: December 1, 1995
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using the newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: June 1, 1995
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report, [January 1, 1996--March 31, 1996]

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized Argonne Premium Coal Samples (APCS) for each rank as a function of (1) size (up to 6nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes. Results of current study on changes in molecular accessibility in APCS coal oxidized in presence of sunlight show that accessibility to spin probes upon O-alkylation of the oxidized coal depends on the percent oxygen present before alkylation. An increase in microporosity occurs upon alkylation and this increase is more pronounced in higher rank than lower ranked coals. It was also observed that the increase in microporosity depends on the structure of each coal.
Date: March 1, 1996
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report, July 1995--September 1995

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: February 1, 1996
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report, October--November 1994

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using a newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: December 1, 1994
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Swelling behavior of O-alkylated APCS coals as examined by the EPR spin probe method

Description: Known O-alkylation procedures have been used to derivatize the carboxyl and hydroxyl groups in the APCS coals Lewiston-Stockton, Wyodak-Anderson, Beulah-Zap, Illinois {number_sign}6, Upper Freeport, and Pittsburgh {number_sign}8. In general the resulting decrease in hydrogen bonding reduced the cyclical variation in nitroxide spin probe retention observed for nonalkylated coals when small amounts (<1%) of pyridine are present in the toluene swelling solvent. An increase in spin probe retention by the O-alkylated coals relative to the underivatized coals indicates a more open arrangement in the coal due to a decrease in attractive forces, confirming that microporosity increases with increasing rank.
Date: December 31, 1995
Creator: Ding, Ruisong; Tucker, D. & Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Magnetic resonance and optical spectroscopic studies of carotenoids. Progress report, December 1, 1994--November 30, 1995

Description: The fundamental goals of this project are (1) to understand the role of a host matrix in the formation and decay mechanisms of carotenoid cation radical and dication and (2) to determine the special properties of carotenoids that enable them to serve as photoprotective agents in photosynthesis and as possible components in electron transfer processes. Results to date are discussed briefly. Work will continue as outlined in the original proposal with emphasis on using simultaneous electrochemistry EPR, and optical methods, variable temperature electrochemistry using microelectrodes and fast scans to examine the more unstable intermediates formed upon electrochemical oxidation of synthetically prepared carotenoids.
Date: June 1, 1995
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Influence of binary swelling solvents: Mechanism of action

Description: This study addresses the dramatic up-take of a poor swelling solvent in Argonne Premium Coal Samples (APCS), Illinois No. 6, Beulah-Zap and Lewiston-Stockton when such a solvent is spiked with various amounts of the strong swelling solvent, pyridine. The unexpected up-take can be explained in terms of four different processes: (1) disruption of weak hydrogen bonds which isolate the interconnected micropore system; (2) disruption of weak hydrogen bonds which protect individual micropores; (3) competition of pyridine for the active sites involved in the hydrogen bonds or the {open_quotes}poisoning{close_quotes} of active sites; and (4) disruption of stronger hydrogen bonds within the macromolecules which causes an opening of the structure. When more than 5% pyridine is used, no additional disruption of the hydrogen-bonded network occurs. The structural changes were monitored by spin probe incorporation which was measured by EPR spectroscopy.
Date: December 31, 1995
Creator: Ding, R.; Tucker, D. & Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Alabama DOE/EPSCoR traineeship program. Final report, September 28, 1991--September 28, 1995

Description: This report covers programmatic accomplishments of the Alabama DOE/EPSCoR Traineeship Program for the period September 28, 1991 to September 29, 1995. The Alabama DOE/EPSCoR Traineeship Program is an integral part of this state`s efforts to address barriers that inhibit the full development and substantial growth of energy-related research at the six major research institutions and at Alabama`s Historically Black Colleges and Universities (HBCUs). To overcome these barriers it was determined that the following actions were needed: Area 1: Strengthening the Research Faculty Base Area 2: Increasing the Number of Outstanding Graduate Students Area 3: Improving the Research Environment Area 4: Developing the Human Resources Base Area 5. Improving the Energy-related Infrastructure, Collaborations and Communications. Although the DOE/EPSCoR Traineeship Grant complements each of the areas listed above, its primary emphasis is the enhancement of opportunities for graduate students. The extent to which this program has met this challenge during the three year funding period constitutes the substance of this report.
Date: December 1, 1995
Creator: Pruitt, K.M. & April, G.C.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using the EPR spin pore method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal as a function of sunlight for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distribution, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: September 1, 1996
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals. Quarterly report, 1996

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes. It appears that the observed binary swelling data for the APCS coals studied to date can be explained in terms of four different processes: one, disruption of weak hydrogen bonds which protect or isolate the interconnected micropore system; two, disruption of weak hydrogen bonds which protect individual micropores; three, the competition of pyridine for the active sites capable of establishing hydrogen bonds or the `poisoning` of active sites; four, disruption of stronger hydrogen bonds within the macromolecular structure which cause an opening of the structure. The contributions of each of these factors to the spin probe retention with increasing concentrations of pyridine vary up to 5% pyridine. At concentrations above 5% pyridine, the first factor becomes less significant, and variations in the others require greater changes in pyridine concentration.
Date: June 1, 1996
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department

Molecular accessibility in oxidized and dried coals: Quarterly report, October 1996--December 1996

Description: The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal as a function of sunlight for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.
Date: December 1, 1996
Creator: Kispert, L.D.
Partner: UNT Libraries Government Documents Department