73222-61-4Relevant articles and documents
1H, 2H, and 13C ENDOR Studies of Labeled Bis(biphenylenyl)propenyl Type Radicals in Isotropic Solutions and in Liquid Crystals
Kirste, B.,Kurreck, H.,Lubitz, W.,Zimmermann, H.
, p. 817 - 825 (1980)
Partially deuterated and 13C-labeled bis(biphenylenyl)propenyl radicals have been studied by means of ESR and ENDOR spectroscopy.Isotropic and anisotropic hyperfine contributions could be determined from measurements in isotropic solutions and in nematic and smectic phases of liquid crystals.Assignments of hyperfine coupling constants and shifts to molecular positions were achieved.Conclusions concerning molecular structure, e.g., twist angles, could be drawn by relating the experimental data to quantum mechanical calculations.These results could be confirmed by taking account of the 13C hyperfine shifts determined by ESR and 13C ENDOR experiments.A marked isotope effect on the β-proton hyperfine coupling could be observed when replacing 1H by 2H in the biphenylenyl moieties.The essential feature of the 2H ENDOR measurements in liquid crystals is the detection of deuterium quadrupole splittings.The relaxation behavior of the different magnetic nuclei is discussed.A novel multinuclear ENDOR standard for checking the engineering design of a liquid-phase ENDOR spectrometer is proposed.
Condensed-phase low temperature heterogeneous hydrogenation of CO2 to methanol
Kothandaraman, Jotheeswari,Dagle, Robert A.,Dagle, Vanessa Labarbier,Davidson, Stephen D.,Walter, Eric D.,Burton, Sarah D.,Hoyt, David W.,Heldebrant, David J.
, p. 5098 - 5103 (2018/10/24)
A low-temperature CH3OH synthesis was achieved at 120-170 °C using tertiary amine and alcohol in the presence of a Cu/ZnO/Al2O3 catalyst by CO2 hydrogenation. A series of 1°, 2° and 3° amines and alcohols were screened to study their influence on the formation of CH3OH. Particularly, 3° amines such as NEt3 in combination with EtOH formed CH3OH with 100% yield with respect to the amine. Unlike the traditional gas-phase heterogeneous metal catalyzed CO2-to-CH3OH reactions, no CO is used in the feed gas mixture in this method. In addition, the hydrogenation gives good selectivity (>95%) to CH3OH and only trace amounts of CO and CH4 are formed. The presence of CO in the gas mixture was attributed to the decomposition of the CH3OH product, which was confirmed by high-temperature and high-pressure MAS NMR. The reaction was performed in the condensed phase at relatively lower temperatures, thus the RWGS reaction, which typically operates at >250 °C, was significantly reduced at these temperatures (120-170 °C). The first in situ spectroscopic evidence for the condensed phase hydrogenation of alkylcarbonate to CH3OH via ammonium formate and alkylformate intermediates was also presented under the experimental conditions.
Synthesis of [1-13C]-para-xylene and [2-13C]-para-xylene
Mormann, Michael,Kuck, Dietmar
, p. 601 - 610 (2007/10/03)
An efficient synthesis of [1-13C]-para-xylene (1a) and [2-13C]-para-xylene (1b) is described. The incorporation of the label has been achieved by cyclocondensation of suitable 1,5-bis(bromomagnesio)alkanes with either ethyl [1-1
