Beeler, AJ
1988-1986
Structural Variations and Evidence of Segmental Motion in the Aliphatic Region in Coals Observed with Dipolar-Dephasing NMR
Soderquist, A.; Burton, D.J.; Pugmire, R.J.; Beeler, A.J.; Grant, D.M.; Durand, B. and Huk, A.Y.
Energy and Fuels, 1, (1), 50-55, 1987. 6 pgs. Funded by US Department of Energy and Standard Oil Co.
We report the structural variations of a number of coals and coal macerals. Through the time constants associated with dipolar-dephasing techniques, CP/MAS spectral data reveal the presence of segmental motion in certain low-rank coal samples. The motion detailed is in the aliphatic region and is thought to be due to CH2 groups associated with hydroaromatic and/or polymethylene structural units.
Low-Temperature C-13 Magnetic Resonance 8. Chemical Shielding Anisotropy of Olefinic Carbons
Orendt, A.M.; Facelli, J.C.; Beeler, A.J.; Reuter, K.; Horton, W.J.; Cutts, P.; Grant, D.M. and Michl, J.
American Chemical Society, 110, 3386, 1988. Funded by US Department of Energy.
The principal values of the C-13 NMR shielding tensor were measured at cryogenic temperatures for a series of olefinic carbons, including methyl-substituted ethylenes, 1-methyl- and 1,2-dimethylcycloalkenes, methylenecycloalkanes, and bicyclo (n,m.0) alkenes. Information on the orientation of the principal axes was obtained from ab initio calculations of the chemical shielding tensor using the IGLO (individual gauge for localized orbitals) method. The results for several compounds with unusual principal values of the shielding tensor were analyzed in terms of the bond contributions in the principal axis system.
Beeler, AJ
1988-1986
Structural Variations and Evidence of Segmental Motion in the Aliphatic Region in Coals Observed with Dipolar-Dephasing NMR
Soderquist, A.; Burton, D.J.; Pugmire, R.J.; Beeler, A.J.; Grant, D.M.; Durand, B. and Huk, A.Y.
Energy and Fuels, 1, (1), 50-55, 1987. 6 pgs. Funded by US Department of Energy and Standard Oil Co.
We report the structural variations of a number of coals and coal macerals. Through the time constants associated with dipolar-dephasing techniques, CP/MAS spectral data reveal the presence of segmental motion in certain low-rank coal samples. The motion detailed is in the aliphatic region and is thought to be due to CH2 groups associated with hydroaromatic and/or polymethylene structural units.
Low-Temperature C-13 Magnetic Resonance 8. Chemical Shielding Anisotropy of Olefinic Carbons
Orendt, A.M.; Facelli, J.C.; Beeler, A.J.; Reuter, K.; Horton, W.J.; Cutts, P.; Grant, D.M. and Michl, J.
American Chemical Society, 110, 3386, 1988. Funded by US Department of Energy.
The principal values of the C-13 NMR shielding tensor were measured at cryogenic temperatures for a series of olefinic carbons, including methyl-substituted ethylenes, 1-methyl- and 1,2-dimethylcycloalkenes, methylenecycloalkanes, and bicyclo (n,m.0) alkenes. Information on the orientation of the principal axes was obtained from ab initio calculations of the chemical shielding tensor using the IGLO (individual gauge for localized orbitals) method. The results for several compounds with unusual principal values of the shielding tensor were analyzed in terms of the bond contributions in the principal axis system.