547-66-0Relevant articles and documents
Insights into the reaction pathway of hydrodeoxygenation of dibenzofuran over MgO supported noble-metals catalysts
Zhang, Jie,Li, Chuang,Chen, Xiao,Guan, Weixiang,Liang, Changhai
, p. 155 - 163 (2019)
Conversion of oxygen-containing compounds derived from lignin arises wide interest due to fossil-derived resources consumption and growing environmental concerns. In this work, hydrodeoxygenation (HDO) of dibenzofuran (DBF) was studied over high-surface-area MgO supported Pt, Pd and Ru catalysts at 370 °C and 1.0 MPa. It was determined that the active metals not only affect the catalytic activity, but also change the reaction pathway of HDO of DBF. The intrinsic activity (TOF) of MgO supported catalysts follows the trend: Pt/MgO (0.36 s?1) > Ru/MgO (0.29 s?1) > Pd/MgO (0.09 s?1), companied by the increasing activate barrier. Pt has a high activity in the hydrogenation of DBF, and exhibits a perfect deoxygenation activity followed by hydrogenation (HYD) pathway. Ru shows better cleavage ability of Caromatic–O bond and the removal of oxygen from DBF mainly occurs via direct deoxygenation (DDO) pathway. The increased Pt loadings largely promote the conversion of DBF by enhancing both HYD and DDO pathways. In addition, more direct cleavage of Caromatic–O bond occurs at higher temperature and the production of aromatics by the DDO pathway prefers the relatively low reaction pressure. Based on the pseudo-first-order kinetics, the analysis of the fitted reaction rate constant shows that the DDO selectivity follows the order: Ru/MgO > Pd/MgO > Pt/MgO, which depends on the capacity of active metals to the cleavage of Caromatic–O bond and the hydrogenation of aromatic ring.
Kinetics of the Thermal Dehydration of Magnesium Oxalate Dihydrate in a Flowing Atmosphere of Dry Nitrogen
Masuda, Yoshio,Iwata, Keiichi,Ito, Ryokou,Ito, Yoshio
, p. 6543 - 6547 (1987)
The kinetics of isothermal dehydration of MgC2O4*2H2O in a dry nitrogen flow have been studied in detail by use of many accurate thermogravimetric data acquired on a microcomputer.This dehydration proceeded as a two-dimensional phase boundary reaction, R2.In general, the nucleation in the phase boundary reaction occurs so rapidly that the reaction rate is only determined by following the chemical process occurring at the reactant-product interface.However, the present dehydration was affected by the nucleation process, and its dehydration fraction curve showed a sigmoid character especially at lower temperatures than ca. 160 deg C.We succeeded in separately evaluating the rate constants kN for the nucleation and k2 for the R2 process by detailed analysis of the dehydration fraction curve.The value of kN became comparable to that of k2 at lower temperatures whereas at higher temperature the former became much larger than the latter and the overall dehydration had a characteristic of natural R2 reaction.The values of activation energies and preexponential factors for both processes were determined from the temperature dependency of kN and k2.Those were 430 kJ mol-1 and 3.73*1049 s-1 for the nucleation process, and 111 kJ mol-1 and 3.40*109 s-1 for two-dimensional phase boundary process, respectively.
Mimicking mineral neogenesis for the clean synthesis of metal-organic materials from mineral feedstocks: Coordination polymers, MOFs and metal oxide separation
Qi, Feng,Stein, Robin S.,Friscic, Tomislav
supporting information, p. 121 - 132 (2014/01/06)
We present a systematic study of a mild approach for the activation of metal oxides, involving reactivity and self-assembly in the solid state, which enables their solvent-free chemical separation and direct solvent-free and low-energy conversion into coordination polymers and open metal-organic frameworks (MOFs). The approach is inspired by geological biomineralization processes known as mineral weathering, in which long-term exposure of oxide or sulfide minerals to molecules of biological origin leads to their conversion into simple coordination polymers. This proof-of-principle study shows how mineral neogenesis can be mimicked in the laboratory to provide coordination polymers directly from metal oxides without a significant input of either thermal or mechanical energy, or solvents. We show that such "aging" is accelerated by increased humidity, a mild temperature increase and/or brief mechanical activation, enabling the transformation of a variety of high-melting (800 °C-2800 °C) transition (MnII, CoII, Ni II, CuII, and Zn) and main group (Mg and PbII) oxides at or near room temperature. Accelerated aging reactions are readily scaled to at least 10 grams and can be templated for the synthesis of two-dimensional and three-dimensional anionic frameworks of Zn, Ni(ii) and Co(ii). Finally, we demonstrate how this biomineralization-inspired approach provides an unprecedented opportunity for solvent-free chemical segregation of base metals, such as Cu, Zn and Pb, in their oxide form under mild conditions.
