cas 643-01-6, L-Mannitol | Articles data

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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
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.
Grindley, T. Bruce,McKinnon, Michael S.,Wasylishen, Roderick E.
p. 41 - 52
(1990)
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Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses
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.
Tindall, Daniel J.,Mader, Steffen,Kindler, Alois,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information
p. 721 - 725
(2020/10/19)

Direct conversion of cellulose into isosorbide over Ni doped NbOPO4catalysts in water
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
Guo, Jiaxing,He, Minyao,Li, Cuiqing,Liu, ShanShan,Song, Yongji,Wang, Hong,Wang, Xincheng
supporting information
p. 10292 - 10299
(2020/07/14)

Highly efficient catalytic conversion of cellulose into acetol over Ni-Sn supported on nanosilica and the mechanism study
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.
Liu, Xiaohao,Liu, Xiaodong,Xu, Guangyue,Zhang, Ying,Wang, Chenguang,Lu, Qiang,Ma, Longlong
p. 5647 - 5656
(2019/11/05)

Role of the Strong Lewis Base Sites on Glucose Hydrogenolysis
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
Yazdani, Parviz,Wang, Bo,Gao, Feng,Kawi, Sibudjing,Borgna, Armando
p. 3845 - 3853
(2018/07/31)

Hydrothermally Stable Ruthenium–Zirconium–Tungsten Catalyst for Cellulose Hydrogenolysis to Polyols
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.
Lucas, Martin,Fabi?ovicová, Katarina,Claus, Peter
p. 612 - 618
(2017/12/28)

METHOD FOR PRODUCING ISOPROPANOL BY CATALYTIC CONVERSION OF CELLULOSE
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℃.
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(2017/07/13)

Influence of the Surface Chemistry of Multiwalled Carbon Nanotubes on the Selective Conversion of Cellulose into Sorbitol
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.
Ribeiro, Lucília S.,Delgado, Juan J.,de Melo órf?o, José J.,Ribeiro Pereira, M. Fernando
p. 888 - 896
(2017/03/13)

One-pot catalytic conversion of cellulose into polyols with Pt/CNTs catalysts
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.
Yang, Li,Yan, Xiaopei,Wang, Qiwu,Wang, Qiong,Xia, Haian
supporting information
p. 87 - 92
(2015/03/05)

Unravelling the Ru-Catalyzed Hydrogenolysis of Biomass-Based Polyols under Neutral and Acidic Conditions
The aqueous Ru/C-catalyzed hydrogenolysis of biomass-based polyols such as erythritol, xylitol, sorbitol, and cellobitol is studied under neutral and acidic conditions. For the first time, the complete product spectrum of C2-C6 polyols is identified and, based on a thorough analysis of the reaction mixtures, a comprehensive reaction mechanism is proposed, which consists of (de)hydrogenation, epimerization, decarbonylation, and deoxygenation reactions. The data reveal that the Ru-catalyzed deoxygenation reaction is highly selective for the cleavage of terminal hydroxyl groups. Changing from neutral to acidic conditions suppresses decarbonylation, consequently increasing the selectivity towards deoxygenation.
Hausoul, Peter J. C.,Negahdar, Leila,Schute, Kai,Palkovits, Regina
p. 3323 - 3330
(2015/10/19)

An easy 'Filter-and-Separate' method for enantioselective separation and chiral sensing of substrates using a biomimetic homochiral polymer
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.
Senthilkumar,Asha
supporting information
p. 8931 - 8934
(2015/05/27)

Direct conversion of cellulose into C6 alditols over Ru/C combined with H+-released boron phosphate in an aqueous phase
Non-edible cellulose has attracted considerable attention to be converted into valuable platform chemicals. Direct transformation of cellulose to C6 alditols (mannitol and sorbitol) provides a sustainable route. A productive approach is presented in this work using a Ru/C catalyst combined with H+-released boron phosphate in an aqueous phase. A yield of C6 alditols as high as 74.9% with a 91% conversion of cellulose is achieved. By adding silica-alumina materials, the yield of C6 alditols can be improved to 93.5% with complete conversion. The acid sites gradually released from boron phosphate under hydrothermal conditions could promote the hydrolysis of cellulose without significant degradation of glucose. Furthermore, the interaction of boric acid with C6 alditols may form borate-polyol complexes, which can enhance the stability of the C6 alditols to avoid further hydrogenolysis and dehydration of the C6 alditols formed. Due to the adsorption ability of the substrate, the addition of silica-alumina materials with a high content of silica leads to improved performance. This journal is
Liu, Yong,Chen, Lungang,Wang, Tiejun,Xu, Ying,Zhang, Qi,Ma, Longlong,Liao, Yuhe,Shi, Ning
p. 52402 - 52409
(2014/12/11)

Aqueous phase hydrogenolysis of glucose to 1,2-propanediol over copper catalysts supported by sulfated spherical carbon
Aqueous phase hydrogenolysis of glucose was carried out over copper catalysts supported by sulfated spherical carbon for selective production of 1,2-propanediol. The sulfated carbon shows higher acidity by sulfation of its resin precursor than unsulfated or commercial ones. By changing copper loading, the hydrogenolysis capability and the acidity of catalysts were modified to suitable extents, which can optimize the selectivity to 1,2-propanediol. At a moderate copper loading, 5.0Cu/s-AC catalyst has the highest yield of 1,2-propanediol. This catalyst has a lifetime of over 300 h. However, its stability is required to be further improved.
Liang, Dong,Liu, Chengwei,Deng, Shuping,Zhu, Yulei,Lv, Chunxiang
p. 108 - 113
(2014/07/08)

Promoting effect of SnOx on selective conversion of cellulose to polyols over bimetallic Pt-SnOx/Al2O3 catalysts
Cellulose is the most abundant source of biomass in nature, and its selective conversion into polyols provides a viable route towards the sustainable synthesis of fuels and chemicals. Here, we report the marked change in the distribution of polyols in the cellulose reaction with the Sn/Pt atomic ratios in a wide range of 0.1-3.8 on the SnOx-modified Pt/Al 2O3 catalysts. Such a change was found to be closely related to the effects of the Sn/Pt ratios on the activity for the hydrogenation of glucose and other C6 sugar intermediates involved in the cellulose reaction as well as to the notable activity of the segregated SnO x species for the selective degradation of the sugar intermediates on the Pt-SnOx/Al2O3 catalysts. At lower Sn/Pt ratios of 0.1-1.0, there existed electron transfer from the SnOx species to the Pt sites and strong interaction between the catalysts, as characterized by temperature-programmed reduction in H2 and infrared spectroscopy for CO adsorption, which led to their superior hydrogenation activity (per exposed Pt atom), and in-parallel higher selectivity to hexitols (e.g. sorbitol) in the cellulose reaction, as compared to Pt/Al 2O3. The hexitol selectivity reached the greatest value of 82.7% at the Sn/Pt ratio of 0.5, nearly two times that of Pt/Al 2O3 at similar cellulose conversions (～20%). As the Sn/Pt ratios exceeded 1.5, the Pt-SnOx/Al2O3 catalysts exhibited inferior hydrogenation activity (per exposed Pt atom), due to the formation of the crystalline Pt-Sn alloy, which led to the preferential conversion of cellulose to C2 and especially C3 products (e.g. acetol) over hexitols, most likely involving the isomerization of glucose to fructose and retro-aldol condensation of these sugars on the segregated SnOx species, apparently in the form of Sn(OH)2. These findings clearly demonstrate the feasibility for rational control of the cellulose conversion into the target polyols (e.g. acetol or propylene glycol), for example, by the design of efficient catalysts based on the catalytic functions of the SnOx species with tunable hydrogenation activity.
Deng, Tianyin,Liu, Haichao
p. 116 - 124
(2013/02/26)

Copper-based catalysts for efficient valorization of cellulose
Noble causes: Cellulose is effectively converted into methanol, propylene, and ethylene glycol over Cu-based catalysts. Overall yields of above 93 %, together with 63 % yield of C1-C3 compounds, can be reached over simple noble-metal
Tajvidi, Kameh,Pupovac, Kristina,Kuekrek, Murhat,Palkovits, Regina
p. 2139 - 2142
(2013/01/15)

Selective conversion of microcrystalline cellulose into hexitols on nickel particles encapsulated within ZSM-5 zeolite
A highly active and selective Ni/ZSM-5 catalyst was prepared by a simple method. A selectivity of 91.2% to hexitols was obtained at intermediate conversion in the hydrolytic hydrogenation of cellulose.
Liang, Guanfeng,Cheng, Haiyang,Li, Wei,He, Limin,Yu, Yancun,Zhao, Fengyu
supporting information; experimental part
p. 2146 - 2149
(2012/09/10)

METHOD FOR PRODUCING ETHYLENE GLYCOL FROM POLYHYDROXY COMPOUND
A method for producing ethylene glycol, including (a) adding a polyhydroxy compound and water to a sealed high-pressure reactor, (b) removing air and introducing hydrogen, and (c) allowing the polyhydroxy compound to react in the presence of a catalyst while stiffing. The catalyst includes a first active ingredient and a second active ingredient. The first active ingredient includes a transition metal of Group 8, 9, or 10 selected from iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, and/or a mixture thereof. The second active ingredient includes a metallic state of molybdenum and/or tungsten, or a carbide, nitride, or phosphide thereof. The method is carried out at a hydrogen pressure of 1-12 MPa, at a temperature of 120-300° C. for not less than 5 min in a one-step catalytic reaction. The efficiency, selectivity, and the yield of ethylene glycol are high. The preparation process is simple and the materials used are renewable.
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(2011/04/14)

Heteropoly acids as efficient acid catalysts in the one-step conversion of cellulose to sugar alcohols
Cellulose and even spruce can be converted efficiently into valuable platform chemicals via combined hydrolysis and hydrogenation in the aqueous phase. Thereby, heteropoly acids together with supported ruthenium catalysts show not only high activity but also remarkable selectivity to sugar alcohols reaching up to 81% yield of C4 to C6 sugar alcohols in only 7 h at 160 °C.
Palkovits, Regina,Tajvidi, Kameh,Ruppert, Agnieszka M.,Procelewska, Joanna
supporting information; experimental part
p. 576 - 578
(2011/03/17)

Transfer hydrogenation of cellulose to sugar alcohols over supported ruthenium catalysts
Ru/C catalysts are active for the conversion of cellulose using 2-propanol or H2 of 0.8 MPa as sources of hydrogen, whereas the Ru/Al 2O3 catalyst is inactive in both reactions, indicating that the Ru/C catalysts are remarkably effective for the cellulose conversion.
Kobayashi, Hirokazu,Matsuhashi, Hisateru,Komanoya, Tasuku,Hara, Kenji,Fukuoka, Atsushi
supporting information; experimental part
p. 2366 - 2368
(2011/04/18)

Amino acid catalyzed neogenesis of carbohydrates: A plausible ancient transformation
Hexose sugars play a fundamental role in vital biochemical processes and their biosynthesis is achieved through enzyme-catalyzed pathways. Herein we disclose the ability of amino acids to catalyze the asymmetric neogenesis of carbohydrates by sequential cross-aldol reactions. The amino acids mediate the asymmetric de novo synthesis of natural L- and D-hexoses and their analogues with excellent stereoselectivity in organic solvents. In some cases, the four new stereocenters are assembled with almost absolute stereocontrol. The unique feature of these results is that, when an amino acid is employed as the catalyst, a single reaction sequence can convert a protected glycol aldehyde into a hexose in one step. For example, proline and its derivatives catalyze the asymmetric neogenesis of allose with > 99% ee in one chemical manipulation. Furthermore, all amino acids tested catalyzed the asymmetric formation of natural sugars under prebiotic conditions, with alanine being the smallest catalyst. The inherent simplicity of this catalytic process suggests that a catalytic prebiotic "gluconeogenesis" may occur, in which amino acids transfer their stereochemical information to sugars. In addition, the amino acid catalyzed stereoselective sequential cross-aldol reactions were performed as a two-step procedure with different aldehydes as acceptors and nucleophiles. The employment of two different amino acids as catalysts for the iterative direct aldol reactions enabled the asymmetric synthesis of deoxysugars with > 99% ee. In addition, the direct amino acid catalyzed C2+C 2+C2 methodology is a new entry for the short, highly enantioselective de novo synthesis of carbohydrate derivatives, isotope-labeled sugars, and polyketide natural products. The one-pot asymmetric de novo syntheses of deoxy and polyketide carbohydrates involved a novel dynamic kinetic asymmetric transformation (DYKAT) mediated by an amino acid.
Cordova, Armando,Ibrahem, Ismail,Casas, Jesus,Sunden, Henrik,Engqvist, Magnus,Reyes, Efraim
p. 4772 - 4784
(2007/10/03)

METHOD OF DESALTING SUGAR SOLUTION AND ANION EXCHANGER
The present invention provides the means for suppressing the production of decomposition reactant, isomerization reactant, colored material, and so on when a saccharide solution is desalted, thereby suppressing the production of impurities and preventing coloration of an ion exchange resin and decrease in the desalting capacity of the ion exchange resin. The desalting of a saccharide solution is performed by using an anion exchange resin supporting a carbonate ion and/or a hydrogencarbonate ion.
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(2008/06/13)

Design and synthesis of new potent C2-symmetric HIV-1 protease inhibitors. Use of L-mannaric acid as a peptidomimetic scaffold
A study on the use of derivatized carbohydrates as C2-symmetric HIV-1 protease inhibitors has been undertaken. L-Mannaric acid (6) was bis-O- benzylated at C-2 and C-5 and subsequently coupled with amino acids and amines to give C2-s
Alterman, Mathias,Bj?rsne, Magnus,Mühlman, Anna,Classon, Bj?rn,Kvarnstr?m, Ingemar,Danielson, Helena,Markgren, Per-Olof,Nillroth, Ulrika,Unge, Torsten,Hallberg, Anders,Samuelsson, Bertil
p. 3782 - 3792
(2007/10/03)

Preparation and structure-activity relationship of novel P1/P1'- substituted cyclic urea-based human immunodeficiency virus type-1 protease inhibitors
A series of novel P1/P1'-substituted cyclic urea-based HIV-1 protease inhibitors was prepared. Three different synthetic schemes were used to assemble these compounds. The first approach uses amino acid-based starting materials and was originally used to prepare DMP 323. The other two approaches use L-tartaric acid or L-mannitol as the starting material. The required four contiguous R,S,S,R centers of the cyclic urea scaffold are introduced using substrate control methodology. Each approach has specific advantages based on the desired P1/P1' substituent. Designing analogs based on the enzyme's natural substrates provided compounds with reduced activity. Attempts at exploiting hydrogen bond sites in the S1/S1' pocket, suggested by molecular modeling studies, were not fruitful. Several analogs had better binding affinity compared to our initial leads. Modulating the compound's physical properties led to a 10-fold improvement in translation resulting in better overall antiviral activity.
Nugiel,Jacobs,Worley,Patel,Kaltenbach III,Meyer,Jadhav,De Lucca,Smyser,Klabe,Bacheler,Rayner,Seitz
p. 2156 - 2169
(2007/10/03)

Total synthesis of the L-hexoses
Enantiomerically pure polyhydroxylated natural products are synthesized by using a reiterative two-carbon extension cycle consisting of four key transformations. The generality and efficiency of this methodology are demonstrated in the total synthesis of all eight L-hexoses.
Ko, Soo Y.,Lee, Albert W. M.,Masamune, Satoru,Reed III, Lawrence A.,Sharpless, K. Barry,Walker, Frederick J.
p. 245 - 264
(2007/10/02)

Interglucosyl Attack of Hydroxyl Group to Epoxy Ring of 2A,3A-Anhydro-(2AS)-α-cyclodextrin. Selective Preparation of 3A,2B-Anhydro-α-cyclodextrin
2A,3A-Anhydro-(2AS)-α-cyclodextrin was isomerized exclusively to 3A,2B-anhydro-α-cyclodextrin by the reaction with aqueous alkali.This implies the selective and interglucosyl attack of 3F-OH to the epoxy ring.
Fujita, Kahee,Tahara, Tsutomu,Sasaki, Hideaki,Egashira, Yoshimitsu,Shingu, Tetsuro,et al.
p. 917 - 920
(2007/10/02)