187995-47-7Relevant academic research and scientific papers
Surfactant-assisted synthesis of mesoporous hafnium- imidazoledicarboxylic acid hybrids for highly efficient hydrogen transfer of biomass-derived carboxides
Dai, Fanglin,Zhou, Shenghui,Qin, Xingzhen,Liu, Detao,Qi, Haisong
, (2019)
Catalytic transfer hydrogenations of biomass-derived carbonyl compounds to produce corresponding alcohols are important pathway for biomass transformation. Herein, a facile route was developed to synthesize the surfactant-assisted heterogeneous acid-base bifunctional 4,5-imidazoledicarboxylic acid-hafnium hybrid catalyst (Hf-H3IDC-T) by hydrothermal self-assembly method. The as-prepared Hf-H3IDC-T was characterized by SEM and TEM, FT-IR spectra, N2 adsorption-desorption, X-ray diffraction patterns (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetry analysis (TG), NH3/CO2-TPD, NMR, GC[sbnd]MS, ICP-OES and elemental analysis. Hf-H3IDC-T hybrid had mesoporous structure and acid-base couple sites. A quantitative yield (99.2%) of furfuryl alcohol (FFA) was obtained from furfural (FUR) over Hf-H3IDC-T using 2-propanol as the hydrogen source under mild conditions. It's found that the amino groups on the imidazole ring is beneficial to enhance the base sites of catalyst. Meanwhile, the addition of hexadecyl trimethyl ammonium bromide (CTAB) as template agents can improve the specific surface area of the catalyst. Dynamic analysis showed that the apparent activation energy of FUR reduction was as low as 50.89 kJ / mol. The as-prepared catalyst has good stability and can be recycled. Finally, the catalyst also has a good catalytic effect on the hydrogenation reaction of aldehydes and ketones of biomass-derived compounds.
Cascade reaction engineering on zirconia-supported mesoporous MFI zeolites with tunable Lewis-Br?nsted acid sites: a case of the one-pot conversion of furfural to γ-valerolactone
Huang, Jun,Kim, Jaeheon,Kim, Jeong-Chul,Kim, Kyung Duk,Ryoo, Ryong,Teoh, Wey Yang
, p. 35318 - 35328 (2020/10/19)
Catalytic cascade reactions are strongly desired as a potential means of combining multistep reactions into a single catalytic reactor. Appropriate catalysts composed of multi-reactive sites to catalyze cascade reactions in a sequential fashion are central to such efforts. Here, we demonstrate a bifunctional zeolite catalyst with close proximity of Br?nsted and Lewis acid sites through the synthesis of a mesoporous ZrO2[Al]MFI nanosponge (NS). The unique mesopores of the MFI-NS allow the confinement of zirconium oxide clusters (Lewis acid sites, LA) within the few-unit-cell-thin MFI aluminosilicate zeolite wall (Br?nsted acid sites, BA). Such a structure is clearly distinct from the conventional MFI zeolite, where the agglomeration of zirconium oxide clusters onto the external surface area within the crystal bulk is not possible, resulting in segregated BA and LA sites on the internal and external zeolite, respectively. By bringing the BA and LA within ZrO2[Al]MFI-NS 30, we uncovered a more efficient catalytic route for the conversion of furfural (100% within 2 h) to γ-valerolactone (GVL) (83%). This route is only evident when the long molecular diffusion path, in the most extreme case of physically mixed ZrO2-(LA) and Al-zeolites (BA) (45% of GVL yield), is eliminated. Unlike the bifunctional ZrO2-Al-beta (GVL yield of 75%), where the BA concentration is greatly compromised at the expense of LA formation, we also show that the ZrO2[Al]MFI-NS is able to maintain a high density and good stability of both types of acids.
Metal-exchanged magnetic β-zeolites: Valorization of lignocellulosic biomass-derived compounds to platform chemicals
Jorge, Erlen Y. C.,Lima, Thiago De M.,Lima, Carolina G. S.,Marchini, Lucas,Castelblanco, William N.,Rivera, Daniel G.,Urquieta-González, Ernesto A.,Varma, Rajender S.,Paix?o, Márcio W.
supporting information, p. 3856 - 3868 (2017/08/22)
An array of magnetically recoverable β-zeolites exchanged with late transition metals (Pd, Fe and Ir) have been synthesized and fully characterized and had their catalytic activity evaluated on the conversion of several bio-derived compounds to other value-added platform chemicals. The nature of the transition metals exchanged in the zeolite matrix and the significant effect of reaction conditions such as temperature, time and solvent usage on both the conversion and selectivity of the process are delineated.
