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171.
172.
The present work deals with thermo-catalytic decomposition of pyrolytic oil from the scrap tire pyrolysis process. Such oil can be used as a model tar in an experimental study of tar removal from pyrolysis or gasification process gas. Several experiments under different conditions were carried out in order to determine conditions of the gasification and pyrolysis processes. Influence of the oil to steam ratio, temperature, and of the presence of dolomite catalyst was studied. Addition of water steam has positive effect on the hydrogen content in the outgoing process gas as well as on the conversion of the injected oil. The catalytic gasification experiment in a quasi steady state produced process gas with the composition: 61 mole % of H2, 6.4 mole % of CO, and 11.7 mole % of CH4. At temperatures lower than 800°C, the amount of process gas decreased resulting also in a decrease of the oil conversion. A comparison of gasification experiments using fresh calcined dolomite with experiments proceeding with regenerated dolomite was done under the same conditions. There was a decrease in the process gas volumetric flow when regenerated catalyst was used. 相似文献
173.
174.
The Molecular and Crystal Structures of 2-Iodokojic Acid: Experimental and Theoretical Determination
František Šimo Ján Moncol Rastislav Šípoš Zdeňka Padělková Jozef Šima 《Journal of chemical crystallography》2011,41(8):1093-1098
Abstract
The crystal structure of 2-iodokojic acid, (2-jodo-3-hydroxy-6-hydroxymethyl)-4-H-pyran-4-one) (C6H5IO4, Mr = 268.00) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the orthorhombic crystal system with space group Pc21b and unit cell parameters: a = 4.0830(2), b = 15.3510(5), c = 23.517(1) ? and Z = 8. The final reliability index is 0.0288 for 2,584 observed reflections. The two molecules of iodokojic acid, slightly differing in their molecular structure, are localized in independent part of unit cell. The crystal packing is stabilized by O–H···O hydrogen bonds and I···O intermolecular interactions. The molecular structure of iodokojic acid determined experimentally little differs from that obtained by the applied theoretical (Hartree–Fock and four versions of DFT) methods, the differences should not be taken as a measure of the reliability of the theoretical methods. 相似文献175.
Abstract The Flory lattice approach for rod-like molecules is extended to encompass the position-restricted (smectic-A) phase. The phase equilibria conditions are obtained from equity of relevant chemical potentials, together with minimization conditions of the Gibbs potential with respect to the system orientational (Flory disorder index, y) and positional (translational disorder index, ζ in the smectic phase) order. 相似文献
176.
Guuske F. Busscher Laurent Lefort Jozef G.O. Cremers Marco Mottinelli Roel W. Wiertz Ben de Lange Yutaka Okamura Yukinori Yusa Kazuhiko Matsumura Hideo Shimizu Johannes G. de Vries André H.M. de Vries 《Tetrahedron: Asymmetry》2010,21(13-14):1709-1714
Two routes for the preparation of an N-aryl β-amino acid, an important precursor for the cholesterol-lowering drug Ezetimibe, were investigated. The first pathway proceeds via an Rh- or Ir-catalyzed asymmetric hydrogenation of N-aryl enamine giving the desired product with up to 82% ee. The other pathway involves a direct asymmetric reductive amination (DARA) of the β-keto ester which yielded the β-amino ester in high yield and 97% ee. Subsequent copper-catalyzed N-arylation gave the target compound. 相似文献
177.
Miroslav Kocifaj Jozef Klačka František Kundracik Gorden Videen 《Annalen der Physik》2015,527(11-12):765-769
Electromagnetic theories have reproduced the scattering properties of differently shaped particles and successfully been used to characterize numerous systems. However, certain anomalous features remain unexplained that include enhanced extinction when particles are much smaller than the wavelength. Here we explain these features exploiting recent research in electromagnetic scattering theories that suggests incorporating the effect of particle charge results in new physical outcomes that deviate appreciably from what is predicted by electromagnetic interaction from uncharged systems. For electrically charged particles, the resonant excitation of surface modes is governed by excess charges deposited on the particle surface. Charge effects become large when particles are small compared to the incident wavelength, and we show that the electrostatic approximation is not valid for modelling the electromagnetic interaction from such particles. Charge‐induced resonances appear in such systems that can reproduce previously unexplained phenomena, for instance, amplified microwave attenuation observed in sandstorms.
178.
179.
Jan Moncol Zuzana Vasková Petra Stachová Jozef Svorec Reijo Sillanpää Milan Mazúr Dušan Valigura 《Journal of chemical crystallography》2010,40(2):179-184
Abstract
The synthesis, spectral characterization and crystal structure of two new nitrobenzoatocopper(II) complexes, namely, [Cu2(2-O2Nbz)4(nia)2]·ACN (1) and [Cu2(2-O2Nbz)4(ACN)2] (2) (where 2-O2Nbz = 2-nitrobenzoate, nia = nicotinamide and ACN = acetonitrile) are reported. The complexes 1 and 2 form dinuclear units of the paddle-wheel type around the crystallographic inversion centers. The copper ions are bridged by four 2-nitrobenzoate anions and the neutral N-donor ligands, viz. nicotinamide in 1 and acetonitrile in 2, are coordinated at apical positions. Selected geometric parameters of both complexes are compared with values for related tetra-2-nitrobenzoate complexes of copper(II) as well as the other dimeric copper(II) carboxylates with apical nicotinamide and acetonitrile ligands. The molecules of 1 are linked with N–H···O and C–H···O hydrogen bonds. The π–π stacking interactions in 1 are observed between benzene rings of 2-nitrobenzoate anions and pyridine rings of nicotinamide and also between acetonitrile molecules and benzene rings of 2-nitrobenzoate anions. The C–H···O hydrogen-bonds and CH/π interactions are observed in crystal structure of 2. 相似文献180.