3857-25-8Relevant articles and documents
Selective aldehyde reductions in neutral water catalysed by encapsulation in a supramolecular cage
Paul, Avishek,Shipman, Michael A.,Onabule, Dolapo Y.,Sproules, Stephen,Symes, Mark D.
, p. 5082 - 5090 (2021)
The enhancement of reactivity inside supramolecular coordination cages has many analogies to the mode of action of enzymes, and continues to inspire the design of new catalysts for a range of reactions. However, despite being a near-ubiquitous class of reactions in organic chemistry, enhancement of the reduction of carbonyls to their corresponding alcohols remains very much underexplored in supramolecular coordination cages. Herein, we show that encapsulation of small aromatic aldehydes inside a supramolecular coordination cage allows the reduction of these aldehydes with the mild reducing agent sodium cyanoborohydride to proceed with high selectivity (ketones and esters are not reduced) and in good yields. In the absence of the cage, low pH conditions are essential for any appreciable conversion of the aldehydes to the alcohols. In contrast, the specific microenvironment inside the cage allows this reaction to proceed in bulk solution that is pH-neutral, or even basic. We propose that the cage acts to stabilise the protonated oxocarbenium ion reaction intermediates (enhancing aldehyde reactivity) whilst simultaneously favouring the encapsulation and reduction of smaller aldehydes (which fit more easily inside the cage). Such dual action (enhancement of reactivity and size-selectivity) is reminiscent of the mode of operation of natural enzymes and highlights the tremendous promise of cage architectures as selective catalysts.
Selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) under atmospheric hydrogen pressure over carbon supported PdAu bimetallic catalyst
Nishimura, Shun,Ikeda, Naoya,Ebitani, Kohki
, p. 89 - 98 (2014)
Hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) was examined by PdxAuy/C catalysts prepared with various Pd/Au molar ratio (x/y) in the presence of hydrochloric acid (HCl) under an atmospheric hydrogen pressure. Bimetallic PdxAuy/C catalysts had a significant activity for a selective hydrogenation of HMF toward DMF comparing to monometallic Pd/C and Au/C catalysts. To clarify the novelty of PdxAuy/C catalysts, characterizations by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectra (XAFS), a transmission electron microscopy (TEM) and other analytical techniques were studied. XPS and X-ray absorption near-edge structure (XANES) analyses indicated that there was the charge transfer phenomenon from Pd to Au atoms in PdxAuy/C. Existence of PdAu alloy structures in PdxAuy/C was expected by XRD, TEM and extended X-ray absorption fine structure (EXAFS) analyses. Accordingly, we concluded that PdAu alloys supported carbon exhibited a good catalytic performance for a selective hydrogenation of HMF to DMF using an atmospheric hydrogen pressure.
Investigation of the Hydrogenation of 5-Methylfurfural by Noble Metal Nanoparticles in a Microcapillary Reactor
Gmeiner, Julia,Seibicke, Max,Behrens, Silke,Spliethoff, Bernd,Trapp, Oliver
, p. 583 - 587 (2016)
On-column reaction gas chromatography (ocRGC) was successfully utilized as high-throughput platform for monitoring of the conversion and selectivity of hydrogenation of 5-methylfurfural catalyzed by polymer-stabilized Ru and Pd nanoparticles. We were able to elucidate the effect of various reaction conditions, mainly together with the catalyst loading on the conversion rate and the selectivity of the reaction. Our strategy yields significant improvements in reaction analysis times and cost effectiveness in comparison to standard methods. We are able to demonstrate that ocRGC approach provides valuable information about the reaction system that gives scientists a tool to design suitable catalytic systems for enhanced sustainable chemistry in the future. Capillary catalysis: A high-throughput study of the hydrogenation of 5-methylfurfural catalyzed by polymer-stabilized noble metal nanoparticles employing on-column reaction gas chromatography (ocRGC) as high-throughput platform to monitor several reaction pathways and intermediates is presented. The ocRGC approach is shown to provide valuable information about the reaction system that gives scientists a tool to design sustainable catalytic systems.
Palladium catalyzed hydrogenation of biomass derived halogenated furfurals
Meller, Elad,Sasson, Yoel,Aizenshtat, Zeev
, p. 103149 - 103159 (2016)
The formation of valuable products and especially fuel candidates from lignocellulosic biomass is highly desirable. Lignocellulose derived halogenated furfurals formation was reported as highly efficient in comparison to the current existing methods of lignocellulose transformation. However, halogenated furfurals are platform chemicals and not end use chemicals, certainly not for fuels. Therefore, transformation methods of halogenated furfurals into fuels, fuels additives, or other valuable compounds are desirable. In this work we present the hydrogenation of halogenated furfurals over carbon supported palladium catalysts. Palladium catalysts showed better performance in the formation of 5-methyl furfural (MF) from halogenated furfurals compared to other catalysts. The reaction products were identified using GC-MS, FT-IR and NMR, and they were quantified using GC analysis. Catalysts were characterized with SEM, BET and pH meter. The role of catalysts properties and reaction parameters in MF preparation, and their effect on MF yields and selectivity were examined. In addition, the catalysts recovery and reuse in subsequent cycles was examined together with the recovery of hydrochloric acid or hydrobromic acid, formed as by products in halogenated furfurals hydrogenation.
Untangling the active sites in the exposed crystal facet of zirconium oxide for selective hydrogenation of bioaldehydes
Devi, Mayanglambam Manolata,Kansal, Sushil Kumar,Kumar, Sahil,Saravanamurugan, Shunmugavel
, p. 7016 - 7026 (2020)
The present study reports the influence of the crystal phase, facets, and active sites of zirconium oxide (ZrO2) on the conversion of bio-aldehydes to their corresponding alcohols in isopropanol under mild reaction conditions. Various ZrO2-based catalysts, having different compositions of monoclinic and tetragonal crystal phases, are successfully prepared in the presence of a base via a solvothermal process. From the detailed characterization through XRD, TEM, CO2-TPD, XPS, AES, BET and poisoning studies, M-ZrO2-U-N, synthesized using zirconium oxynitrate and urea as a precursor and precipitant, respectively, in water, possesses a 100% monoclinic crystal phase with a maximum amount of exposed (-111) facets and surface oxygen concentration along with the highest number of basic sites. The catalytic study on the transformation of furfural (FFA) into furfuryl alcohol (FOH) reveals that M-ZrO2-U-N exhibits the best efficiency with a nearly quantitative yield of FOH. On the other hand, T-ZrO2-U-N, synthesized using zirconium oxynitrate and urea as a precursor and precipitant, respectively, in methanol, is found to have a 94.4% tetragonal phase and a 2.2-fold lower number of basic sites in comparison with M-ZrO2-U-N. The catalytic result with T-ZrO2-U-N displays the lowest activity in terms of the FOH yield (8.1%). According to the comparative and systematic catalytic studies with the various ZrO2 catalysts having different amounts of tetragonal and monoclinic phases, the ZrO2 catalyst having a more monoclinic phase with more exposed (-111) facets, basic sites, surface oxygen species and surface area is found to be crucial for the FFA conversion to FOH with high selectivity. M-ZrO2-U-N is found to be stable and recyclable and also shows excellent activity towards the transformation of other bio-aldehydes and ketones into their corresponding alcohols. This journal is
Highly efficient catalytic transfer hydrogenation of biomass-derived furfural to furfuryl alcohol using UiO-66 without metal catalysts
Guo, Tianmeng,Li, Danni,Qi, Xinhua,Qiu, Mo,Xi, Ran
, (2020)
In this paper, the as-prepared metal-organic frameworks material UiO-66 and other Zr-MOFs were directly used as catalytic transfer hydrogenation (CTH) catalysts to catalyze furfural (FF) to furfuryl alcohol (FAL) with 2-propanol (IPA) acted as both solvent and hydrogen donor. The results showed that the as-prepared UiO-66 had satisfactory catalytic activity and selectivity in yielding FAL (97 %) from the CTH of FF at 140 °C within 5 h. Moreover, the as-prepared UiO-66 exhibited relatively stable catalytic activity over five cycles and easy regeneration. Interestingly, UiO-66 was also applicable for the CTH of the other aldehydes such as 5-hydroxymethyfurfural, 5-methylfurfural, 4-methoxybenzaldehyde, and n-hexanal to the corresponding alcohols, affording high product yields up to 98 %. This work provides a green, simple and sustainable process for the catalytic production of FAL from biomass-based furfural, which has certain significance for the sustainable utilization of biomass.
Cu1-Cu0 bicomponent CuNPs@ZIF-8 for highly selective hydrogenation of biomass derived 5-hydroxymethylfurfural
Feng, Yunchao,Yan, Guihua,Wang, Ting,Jia, Wenlong,Zeng, Xianhai,Sperry, Jonathan,Sun, Yong,Tang, Xing,Lei, Tingzhou,Lin, Lu
, p. 4319 - 4323 (2019)
99% yield of 2,5-dihydroxymethylfuran (DHMF) was achieved from biomass derived 5-hydroxymethylfurfural (HMF) with novel CuNPs@ZIF-8 using a relatively low hydrogen pressure and short reaction time. The activation energy of transformation of HMF to DHMF is only 39 kJ mol-1 and the TOF value reached is 21 h-1. The coexistence of Cu1 and Cu0 in Cu species is demonstrated to contribute to the high activity for the hydrogenation of HMF to DHMF.
Catalytic conversion of starch into valuable furan derivatives using supported metal nanoparticles on mesoporous aluminosilicate materials
Yepez, Alfonso,Garcia, Angel,Climent,Romero, Antonio A.,Luque, Rafael
, p. 428 - 434 (2014)
Catalytically active supported metal nanoparticles on aluminosilicates including Cu and Pd-based systems were investigated in the microwave-assisted conversion to a range of valuable furanic compounds via tandem formic acid-promoted dehydration and subsequent selective hydrogenation processes. Results show that interesting selectivities to reduced products including 5-methylfurfural and 5-methylfurfuryl alcohol as well as hydroxymethylfurfural and furfural could be obtained in various proportions depending on the type of catalyst and the investigated reaction conditions. The investigation of reaction parameters including time of reaction, type of catalyst, quantity of catalyst and formic acid content indicated that reaction conditions can in principle be fine-tuned to maximise selectivity towards individual products. The Royal Society of Chemistry.
Catalytic in-situ hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran over Cu-based catalysts with methanol as a hydrogen donor
Zhang, Zihao,Wang, Changxue,Gou, Xin,Chen, Hao,Chen, Kequan,Lu, Xiuyang,Ouyang, Pingkai,Fu, Jie
, p. 245 - 250 (2019)
A series of Cu-based catalysts with different supports were synthesized and studied for the in situ hydrogenation of 5-hydroxymethylfurfural (5-HMF) to dimethylfuran (DMF) using methanol as an economical hydrogen donor. The structures and properties of the four catalysts (Cu/Al2O3, Cu/ZnO, Cu/ZrO2, and Cu/CeO2) were characterized using X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), and temperature-programmed desorption of ammonia (NH3-TPD). The experimental results showed that the use of different supports for the Cu-based catalysts significantly influenced their activity for both H2 production from methanol and hydrogenation of 5-HMF. The catalyst Cu/Al2O3 showed the best catalytic activity, which can be attributed to the highest activity for the in situ H2 production from methanol, smallest Cu crystallite size, and strongest acidity. The effects of the substrate concentration, catalyst loading, and reaction temperature and time on the in situ hydrogenation of 5-HMF were systematically investigated to determine the optimum reaction conditions.
Multifunctional NiCoTi?Catalyst Derived from Layered Double Hydroxides for Selective Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran
Ma, Ning,Song, Yong,Han, Feng,Waterhouse, Geoffrey I. N.,Li, Yan,Ai, Shiyun
, p. 517 - 525 (2021)
Multifunctional NiCoTi metal oxide catalysts (denoted herein as NiCoTi-x, where x is the molar ratio Ni + Co:Ti) were successfully prepared by thermal treatment of NiCoTi layered double hydroxide (LDH) precursors. The NiCoTi-x catalysts were then applied to the hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF). The Ni:Co:Ti molar ratio in the catalysts was found to strongly influence both catalyst activity and product selectivity. A NiCoTi-8 catalyst, containing Ni, Co and Ti in a 4:4:1 molar ratio (i.e. Ni + Co/Ti = 8), displayed outstanding performance for HMF hydrogenation at 200?°C and 1.5?MPa, evidenced by a 90.7% HMF conversion and 95.8% selectivity to DMF. Graphic Abstract: A ternary metal oxide catalyst derived from a layered double hydroxide was proposed for the efficient and selective hydrogenation of 5-hydroxymethylfurfural to 2,5-methylfuran.[Figure not available: see fulltext.]
