629-11-8Relevant articles and documents
Determining Roles of Cu0 in the Chemosynthesis of Diols via Condensed Diester Hydrogenation on Cu/SiO2 Catalyst
Wang, Weichao,Wang, Hui,Zhang, Jingwei,Kong, Lingxin,Huang, Huijiang,Liu, Wei,Wang, Shengping,Ma, Xinbin,Zhao, Yujun
, p. 3849 - 3852 (2020)
Copper-based catalyst was applied in the condensed diester hydrogenation with unexpected high selectivity (~100 percent) to 1,6-hexanediol. On basis of the mass transfer analysis and kinetics results, the reaction rate of the condensed diester hydrogenation was deduced to be controlled by the activation of hydrogen on Cu0 sites, which was further demonstrated by the correlations between the catalytic activity and different copper species. Importantly, this catalysis mechanism is different with that of gas-phase diester hydrogenation, which is generally determined by the adsorption of ester on Cu+ species.
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Raphael,Roxburgh
, p. 3875 (1952)
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Synthesis of Supported RhMo and PtMo Bimetallic Catalysts by Controlled Surface Reactions
Alba-Rubio, Ana C.,Sener, Canan,Hakim, Sikander H.,Gostanian, Thomas M.,Dumesic, James A.
, p. 3881 - 3886 (2015)
We previously described a synthesis method to prepare bimetallic catalysts with narrow nanoparticle size and composition distributions by means of controlled surface reactions (CSR) between a reduced supported metal nanoparticle and an organometallic precursor of an oxophilic promoter metal. Herein, we report a comparison of such catalysts with those prepared by traditional incipient wetness impregnation. STEM/EDS analysis indicates that catalysts prepared by CSR exhibit more effective interaction of metals, thereby minimizing the undesirable formation of component-rich nanoparticles and/or monometallic domains. Reaction kinetics studies using these bimetallic catalysts reveal that optimal conversion rates in a selective CO hydrogenolysis reaction (i.e., hydrogenolysis of 2-(hydroxymethyl)tetrahydropyran to 1,6-hexanediol) could be achieved using a lower amount of the oxophilic promoter metal for the catalysts prepared by the CSR approach, as compared to their impregnated counterparts. A superior method for greater results: At the same conversion rate level, catalysts prepared by controlled surface reactions (CSR) requires smaller amount of promoter as compared to those prepared by incipient wetness impregnation (IWI). This increased performance is attributed to the uniform bimetallic composition of the catalysts prepared by CSR.
Reductive depolymerization of polyesters and polycarbonates with hydroboranes by using a lanthanum(iii) tris(amide) catalyst
Berthet, Jean-Claude,Cantat, Thibault,Kobylarski, Marie
supporting information, p. 2830 - 2833 (2022/03/09)
The homogeneous reductive depolymerization of polyesters and polycarbonates with hydroboranes is achieved with the use of an f-metal complex catalyst. These polymeric materials are transformed into their value-added alcohol equivalents. Catalysis proceeds readily, under mild conditions, with La[N(SiMe3)2]3 (1 mol%) and pinacolborane (HBpin) and shows high selectivity towards alcohols and diols, after hydrolysis.
Understanding of the key properties of supported Cu-based catalysts and their influence on ester hydrogenolysis
Aubrecht, Jaroslav,Kikhtyanin, Oleg,Kubi?ka, David,Lhotka, Miloslav,Pospelova, Violetta
, (2021/10/19)
The application of Cr-free Cu-based catalysts in ester hydrogenolysis is a modern environmentally-friendly research approach. The comprehensive study of four supported Cu-based catalysts was performed using 8 wt% of Cu loaded on Al2O3, ZnO, TiO2 and ZrO2 supports by an impregnation method. Using XRD, H2-TPR, BET, pyridine-TPD, CO2-TPD and N2O-RFC methods, the effect of the support on the formation of Cu-nanoparticles was described. Al2O3 was evaluated as the support ensuring the highest nanoparticles dispersion, while Cu nanoparticles in Cu-TiO2 were liable to sintering. The catalysts were tested in dimethyl adipate hydrogenolysis, where the catalyst performance and activity (TOF) were evaluated and Cu-ZrO2 showed the best results. A correlation between the number of acid-base sites and the catalyst selectivity was revealed and the catalyst effect on the formation of various by-products was described. The intrinsic selectivity to hydrogenolysis products was found to decrease with the increasing acid-base character of the supports whereas the selectivity to transesterification and cyclization products increased. The hydrogenolysis activity was not a simple function of the number of the surface copper atoms, but it was affected by the support nature and its properties.