643-01-6Relevant academic research and scientific papers
TOWARDS UNDERSTANDING (13)C-N.M.R. CHEMICAL SHIFTS OF CARBOHYDRATES IN THE SOLID STATE. THE SPECTRA OF D-MANNITOL POLYMORPHS AND OF DL-MANNITOL
Grindley, T. Bruce,McKinnon, Michael S.,Wasylishen, Roderick E.
, p. 41 - 52 (1990)
The cross-polarization, magic-angle spinning (13)C-n.m.r. spectra of solid DL-mannitol and of three polymorphs of D-mannitol have been recorded and assigned.Recrystallization of D-mannitol from several solvents under different conditions gave either one of the three known pure polymorphs or mixtures containing two or more of these polymorphs.The (13)C-chemical shifts from the four species in the solid state were all less than the solution values.Conformations in deuterium oxide and di((2)H3)methyl sulfoxide solutions were obtained from the vicinal proton coupling constants that resulted from analysis of the (1)H-n.m.r. spectra.The major cause of the differences between solid-state and solution chemical shifts is that there are significant populations of one of the gauche rotamers and the anti O-C-C-C rotamer about the terminal C-C bonds in solution.Other effects on solid-state (13)C-chemical shifts are discussed.
Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses
Tindall, Daniel J.,Mader, Steffen,Kindler, Alois,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information, p. 721 - 725 (2020/10/19)
Sugar alcohols are of great importance for the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H2, usually with none to low stereoselectivities. Now, we present a homogeneous system based on commercially available components, which not only increases the overall yield, but also allows a wide range of unprotected ketoses to be diastereoselectively hydrogenated. Furthermore, the system is reliable on a multi-gram scale allowing sugar alcohols to be isolated in large quantities at high atom economy.
Direct conversion of cellulose into isosorbide over Ni doped NbOPO4catalysts in water
Guo, Jiaxing,He, Minyao,Li, Cuiqing,Liu, ShanShan,Song, Yongji,Wang, Hong,Wang, Xincheng
supporting information, p. 10292 - 10299 (2020/07/14)
Isosorbide is a versatile chemical intermediate for the production of a variety of drugs, chemicals, and polymers, and its efficient production from natural cellulose is of great significance. In this study, bifunctional catalysts based on niobium phosphates were prepared by a facile hydrothermal method and used for the direct conversion of cellulose to isosorbide under aqueous conditions. NH3-TPD analysis showed that a high acid content existed on the catalyst surface, and pyridine infrared spectroscopic analysis confirmed the presence of both Lewis acid and Br?nsted acid sites, both of which played an important role in the process of carbohydrate conversion. XRD and H2-TPR characterization determined the composition and the hydrogenation centers of the catalyst. An isosorbide yield of 47% could be obtained at 200 °C for 24 h under 3 MPa H2 pressure. The Ni/NbOPO4 bifunctional catalyst retains most of its activity after five consecutive runs with slightly decreased isosorbide yield of 44%. In addition, a possible reaction mechanism was proposed that the synergistic effect of surface acid sites and hydrogenation sites was favorable to enhancing the cascade dehydration and hydrogenation reactions during the conversion of cellulose to isosorbide. This study provides as an efficient strategy for the development of novel multifunctional heterogeneous catalysts for the one-pot valorisation of cellulose. This journal is
Highly efficient catalytic conversion of cellulose into acetol over Ni-Sn supported on nanosilica and the mechanism study
Liu, Xiaohao,Liu, Xiaodong,Xu, Guangyue,Zhang, Ying,Wang, Chenguang,Lu, Qiang,Ma, Longlong
, p. 5647 - 5656 (2019/11/05)
Selective conversion of cellulose into high value-added C3 chemicals is a great challenge in biorefinery due to the complicated reaction process. In this work, 61.6% yield of acetol was obtained by one pot conversion of cellulose using Ni-Sn/SiO2 catalysts. A series of characterization methods including TEM, STEM-HAADF, EDS, AAS, XRD, XPS, H2-TPR, Py-FTIR, and CO2-TPD were carried out to explore the structure-activity relationship. The strong basicity of the catalysts was a key factor affecting the production of acetol. In addition, catalysts with the hydrothermally stable L-acid sites and no B-acid sites inhibited side reactions and ensured efficient conversion of cellulose into small molecules. Further studies showed that the formation of the Ni3Sn4 alloy significantly promoted the acetol production, and its weak hydrogenation activity inhibited further conversion of acetol. Noninteger valence tin species (Snδ+ and SnOx) were formed both in Ni3Sn4 and Sn/SiO2. These Sn species were the source of basic sites and the active sites for catalyzing cellulose to acetol. Under the synergistic catalysis of Sn/SiO2 and the Ni3Sn4 alloy, cellulose was efficiently converted into acetol. This work provides guidance for the selective conversion of cellulose into C3 products.
Hydrothermally Stable Ruthenium–Zirconium–Tungsten Catalyst for Cellulose Hydrogenolysis to Polyols
Lucas, Martin,Fabi?ovicová, Katarina,Claus, Peter
, p. 612 - 618 (2017/12/28)
In this work, we describe a catalytic material based on a zirconium–tungsten oxide with ruthenium for the hydrogenolysis of microcrystalline cellulose under hydrothermal conditions. With these catalysts, polyols can be produced with high yields. High and stable polyol yields were also achieved in recycling tests. A catalyst with 4.5 wt % ruthenium in total achieved a carbon efficiency of almost 100 %. The prepared Zr-W oxide is mesoporous and largely stable under hydrothermal conditions (493 K and 65 bar hydrogen). Decomposition into the components ZrO2 and WO3 could be observed at temperatures of 1050 K in air.
Role of the Strong Lewis Base Sites on Glucose Hydrogenolysis
Yazdani, Parviz,Wang, Bo,Gao, Feng,Kawi, Sibudjing,Borgna, Armando
, p. 3845 - 3853 (2018/07/31)
This work reports the individual role of strong Lewis base sites on catalytic conversion of glucose hydrogenolysis to acetol/lactic acid, including glucose isomerisation to fructose and pyruvaldehyde rearrangement/hydrogenation to acetol/lactic acid. Las
METHOD FOR PRODUCING ISOPROPANOL BY CATALYTIC CONVERSION OF CELLULOSE
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Page/Page column 9, (2017/07/13)
This invention provides a method for producing isopropanol from cellulose, which is characterized by: cellulose is catalytically converted to isopropanol under existence of a Cu-Cr catalyst. In the method, the Cu-Cr catalyst contains an active phase of CuCr2O4 or further contains an active phase selected from a group consisting of CuO and Cr2O3; the mass ratio of cellulose and water is 15 wt% or below; and the temperature of catalytic reaction is 200-270℃.
Influence of the Surface Chemistry of Multiwalled Carbon Nanotubes on the Selective Conversion of Cellulose into Sorbitol
Ribeiro, Lucília S.,Delgado, Juan J.,de Melo órf?o, José J.,Ribeiro Pereira, M. Fernando
, p. 888 - 896 (2017/03/13)
Carbon nanotubes (CNT) were submitted to liquid-phase chemical treatments using HNO3 and subsequently to gas-phase thermal treatments to incorporate different sets of oxygenated groups on the surface. The modified CNT were used as supports for 0.4 wt % Ru in the direct conversion of ball-milled cellulose to sorbitol and high conversions were reached after 3 h at 205 °C. Ru supported on the original CNT, although less active, was the most selective catalyst for the one-pot process (70 % sorbitol selectivity after 2 h). Unlike the one-pot process, the support acidity greatly promoted the rate of cellulose hydrolysis (35 % increase after 2 h) and the glucose selectivity (12 % increase after 2 h). The rate of glucose hydrogenation was almost not affected by the support modification. However, the catalyst acidity improved the sorbitol selectivity from glucose. The support acidity was a central factor for the one-pot conversion of cellulose, as well as for the individual hydrolysis and hydrogenation steps, and the original CNT supported Ru catalyst was the most efficient and selective catalyst for the direct conversion of cellulose to sorbitol.
An easy 'Filter-and-Separate' method for enantioselective separation and chiral sensing of substrates using a biomimetic homochiral polymer
Senthilkumar,Asha
supporting information, p. 8931 - 8934 (2015/05/27)
We present a polyfluorene appended with protected l-glutamic acid that exhibited a reversible α-helix/β-sheet-like conformation and helical porous fibrous morphology mimicking the super-structure of proteins. The new homochiral polymer probe enabled efficient heterogeneous enantioselective separation and chiral sensing of a wide variety of substrates from their aqueous racemic mixture using an easy 'Filter-and-Separate' method.
One-pot catalytic conversion of cellulose into polyols with Pt/CNTs catalysts
Yang, Li,Yan, Xiaopei,Wang, Qiwu,Wang, Qiong,Xia, Haian
supporting information, p. 87 - 92 (2015/03/05)
A series of Pt nanoparticles supported on carbon nanotubes (CNTs) were synthesized using the incipient-wetness impregnation method. These catalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM) techniques. The characterization results indicate that the Pt nanoparticles were highly dispersed on the surface of the CNTs, and the mean size was less than 5 nm. These catalysts were utilized to convert cellulose to hexitol, ethylene glycerol (EG), and 1,2-propylene glycol (1,2-PG) under low H2 pressure. The total yields were as high as 71.4% for EG and 1,2-PG using 1 Pt/CNTs as the catalyst in the hydrolytic hydrogenation of cellulose under mild reaction conditions.
