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Molecular accessibility in solvent swelled coals. Quarterly report

Description: An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the … more
Date: February 1, 1993
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coals. Final report

Description: The conversion of coal by an economically feasible catalytic method requires the catalyst to diffuse into the coal sample so that hydrogenation catalysis can occur from within as well as the normal surface catalysis. Thus an estimate of the size, shape, and reactivity, of the pores in the coal before and after the swelling with different solvents is needed so that an optimum sized catalyst will be used. This study characterizes the accessible area found in Argonne Premium Coal Samples (APCS) us… more
Date: April 1, 1994
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coals. Quarterly report, [September--November, 1993]

Description: This quarter, experiments were performed on the use of binary swelling solvents in molecular accessibility in coal conversion. These experiments consisted of accessibility measurements of spin probe VII (TEMPAMINE) in Toluene swelled Illinois No. 6 APCS coal. The toluene was spiked with amounts of pyridine which ranged in concentration from 500 ppm to 10%. The experiments were done in triplicate to gain information about the experimental error involved in the procedure. It was shown that oscill… more
Date: November 1, 1993
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coals

Description: An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a non swelling solvent to eliminate any spin probes that are not trapped in the pores and the … more
Date: February 1, 1993
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coals. Quarterly report, [April--June 1993]

Description: The effect of weathering (oxidation and dehydration upon exposure to air) on the molecular accessibility of potential catalysts was studied by the EPR spin probe technique. Fresh samples of all 8 APCS coals were exposed to air for periods up to 36 days. Weathering produced significant effects on the retention of spin probes in most of the APCS coals under 91 % carbon (dmmf). It was determined that the lower ranked coal (Beulah Zap and Wyodak) under went a structural collapse which precluded ret… more
Date: August 1, 1993
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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 … more
Date: December 31, 1995
Creator: Ding, Ruisong; Tucker, D. & Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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 electrochemist… more
Date: June 1, 1995
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An EPR spin probe method for characterizing changes in the accessible regions of coal upon oxidation

Description: Eight Argonne Premium Coal Samples (APCS) were weathered in air and the structural and chemical changes that upon swelling with toluene and pyridine were, examined by an EPR spin probe method developed in this laboratory. Under mild oxidation conditions and swelling with toluene large structural changes were observed for lignite (Beulah-Zap) which suggested the collapse of the coal structure. This did not occur for higher rank coal. Upon oxidation and swelling with toluene and pyridine an incre… more
Date: January 1, 1992
Creator: Sady, W.; Kispert, L. D. & Spears, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

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) co… more
Date: December 31, 1995
Creator: Ding, R.; Tucker, D. & Kispert, L. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

An EPR spin probe method for characterizing changes in the accessible regions of coal upon oxidation

Description: Eight Argonne Premium Coal Samples (APCS) were weathered in air and the structural and chemical changes that upon swelling with toluene and pyridine were, examined by an EPR spin probe method developed in this laboratory. Under mild oxidation conditions and swelling with toluene large structural changes were observed for lignite (Beulah-Zap) which suggested the collapse of the coal structure. This did not occur for higher rank coal. Upon oxidation and swelling with toluene and pyridine an incre… more
Date: September 1, 1992
Creator: Sady, W.; Kispert, L. D. & Spears, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal

Description: Research continued on the swelling of coal. Changes in the size and number distribution of the accessible regions in five Argonne Premium Coal Samples (APCS No.3, No.4, No.5, No.6, and No.8) upon swelling with the solvents, cyclohexane, toluene, nitrobenzene and pyridine were examined by an EPR spin probe method. It was found that as the basicity of the solvent increased the number and length of the cylindrical pores increased with decreasing rank. The number of cylindrical pores also increased… more
Date: November 1, 1990
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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 distribution… more
Date: December 1, 1995
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in oxidized and dried coals. Quarterly report, [January--March 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 our newly developed EPR spin probe method. Looking at the over-all picture of the because of the increased cross-linking and lack of decrease in retention would be observed because of the increased cross-linking and lack of structural accessibility of the spin probes. This decrease would … more
Date: March 1, 1994
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal

Description: The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal S… more
Date: January 1, 1991
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal

Description: Research continued on the determination of pore size and number distribution changes after swelling the coal samples with various solvents. A paper has just been submitted to the journal Fuel on the Low temperature Swelling of Argonne Premium Coal samples using solvents of varying polarity. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coa… more
Date: August 1, 1991
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in oxidized and dried coals. Quarterly report, October--December 1993

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 6nm) and shape, (2) the relative acidic/basic reactive site distributions, (… more
Date: December 1, 1993
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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, an… more
Date: December 1, 1994
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal

Description: To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were la… more
Date: November 1, 1992
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal

Description: An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the s… more
Date: May 29, 1992
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal. Quarterly report, November 1991

Description: The EPR-spin probe method was used to study the swelling of covalently cross-linked 2%, 4%, 6%, 8% and 12% polystyrene-divinyl benzene copolymers, used as models of APCS coal structural elements. The results were compared with swelling studies on APCS coals and confirmed results showing that coal was polymeric, that it had covalent cross-links increasing with rank, that it was structurally anisotropic, and that its swelling was anisotropic. The low temperature swelling of Argonne Premium Coal S… more
Date: December 31, 1991
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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, … more
Date: March 1, 1995
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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 reac… more
Date: March 1, 1996
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Molecular accessibility in solvent swelled coal. Quarterly report

Description: An EPR technique developed in this lab is being used to determine the pore size and number distribution changes after swelling the coal samples with various solvents. Stable nitroxide radical spin probes of different sizes, shapes and reactivity are dissolved in an appropriate solvent, the coal sample is added to the resulting solution, stirred over night at elevated temperature, filtered, washed with a nonswelling solvent to eliminate any spin probes that are not trapped in the pores and the s… more
Date: May 29, 1992
Creator: Kispert, L. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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