641-74-7Relevant articles and documents
Direct Amination of Isohexides via Borrowing Hydrogen Methodology: Regio- and Stereoselective Issues
Bahé, Florian,Grand, Lucie,Cartier, Elise,Jacolot, Ma?wenn,Moebs-Sanchez, Sylvie,Portinha, Daniel,Fleury, Etienne,Popowycz, Florence
supporting information, p. 599 - 608 (2020/02/04)
The regio and diastereoselective direct mono or diamination of bio-based isohexides (isosorbide and isomannide) has been developed through borrowing hydrogen (BH) methodology using a cooperative catalysis between an iridium complex and a Br?nsted acid. The access to chiral amino-alcohol (NH2-OH) and diamine (NH2-NH2), interesting optically pure bio-based monomers, was also proposed using BH strategy as a sustainable route for their obtention.
Efficient and selective aqueous photocatalytic mono-dehydration of sugar alcohols using functionalized yttrium oxide nanocatalysts
Cheng, Yu,Fan, Chao,Guo, Lina,Huang, Benhua,Li, Xiaoyong,Luque, Rafael,Ma, Xiaomo,Meng, Xu,Pan, Cheng,Sun, Yang,Yang, Juncheng,Zhang, Junjie,Zhang, Weining,Zheng, Aqun
, p. 5333 - 5344 (2020/09/17)
The mono-dehydration of sugar alcohols such as d-sorbitol and d-mannitol generates 1,4-sorbitan and 1,4-mannitan, respectively, which are relevant platform molecules for the synthesis of detergents and pharmaceuticals. Most reported catalytic systems provided access to di-dehydrated products, while mono-dehydration required special efforts, particularly regarding selectivity and reaction temperature. A series of functionalized yttrium oxides were prepared via sol-gel synthesis in this work, which not only showed an interesting micropipe-like morphology, but also contained functional components. These materials were investigated as photocatalysts in the dehydration of d-sorbitol and d-mannitol, exhibiting high selectivity to mono-dehydration. The effects of solvent, temperature and catalyst were fully discussed. A catalytic mechanism was proposed based on the experimental results and calculations.
Kinetic analyses of intramolecular dehydration of hexitols in high-temperature water
Yamaguchi, Aritomo,Mimura, Naoki,Shirai, Masayuki,Sato, Osamu
, (2019/11/29)
Intramolecular dehydration of the biomass-derived hexitols D-sorbitol, D-mannitol, and galactitol was investigated. These reactions were performed in high-temperature water at 523–573 K without added acid catalyst. The rate constants for the dehydration steps in the reaction networks were determined at various reaction temperatures, and the activation energies and pre-exponential factors were calculated from Arrhenius plots. The yield of each product was estimated as a function of reaction time and temperature using the calculated rate constants and activation energies. The maximum yield of each product from the dehydration reactions was predicted over a range of reaction time and temperature, allowing the selective production of these important platform chemicals.
A strategy of ketalization for the catalytic selective dehydration of biomass-based polyols over H-beta zeolite
Che, Penghua,Lu, Fang,Si, Xiaoqin,Ma, Hong,Nie, Xin,Xu, Jie
supporting information, p. 634 - 640 (2018/02/14)
Biomass contains plentiful hydroxyl groups that lead to an oxygen-rich structure compared to petroleum-based chemicals. Dehydration is the most energy-efficient technique to remove oxygen; however, multiple similar vicinal hydroxyl groups in sugar alcohols impose significant challenges for their selective dehydration. Here, we present a novel strategy to control the etherification site in sugar alcohols by the ketalization of the vicinal-diol group for the highly selective formation of tetrahydrofuran derivatives. A ketone firstly reacts with terminal vicinal hydroxyl groups to form the 1,3-dioxolane structure. This structure of the constrained 1,3-dioxolane ring would improve the accessibility of reactive groups to facilitate intramolecular etherification. As a better leaving group than water, the ketone can also promote intramolecular etherification. Consequently, a range of tetrahydrofuran derivatives are produced in excellent yields with the H-beta zeolite catalyst under mild reaction conditions. This strategy opens up new opportunities for the efficient upgrading of biomass via the modification or protection of hydroxyl groups.
Unravelling the Mechanism of the Ru/C-Catalysed Isohexide and Ether Isomerization by Hydrogen Isotope Exchange
Engel, Rebecca V.,Niemeier, Johannes,Fink, Anja,Rose, Marcus
supporting information, p. 2358 - 2363 (2018/05/08)
In this article we show that the catalytic isomerization of isohexide sugar alcohols as well as their respective ethers can occur by a hydride-based mechanism rather than a dehydrogenation/re-hydrogenation. C?H bonds in α-position to hydroxy and ether groups are activated using Ru/C as solid catalyst at temperatures as high as 160 °C and above. Hydrogen isotope exchange experiments proved that a full hydride exchange and isomerization is possible for isohexides but unexpectedly also for their methyl ethers. This is of great importance as it proves the co-existence of the both mechanisms for reactions that were so far assumed to occur solely by a dehydrogenation/re-hydrogenation. Hence, this co-existence should be taken into account for kinetic investigations of such reaction systems especially in the conversion of biomass-based chemicals under hydrogenation conditions. (Figure presented.).
Is water a suitable solvent for the catalytic amination of alcohols?
Niemeier, Johannes,Engel, Rebecca V.,Rose, Marcus
supporting information, p. 2839 - 2845 (2017/07/24)
The catalytic conversion of biomass and biogenic platform chemicals typically requires the use of solvents. Water is present already in the raw materials and in most cases a suitable solvent for the typically highly polar substrates. Hence, the development of novel catalytic routes for further processing would profit from the optimization of the reaction conditions in the aqueous phase mainly for energetic reasons by avoiding the initial water separation. Herein, we report the amination of biogenic alcohols in aqueous solutions using solid Ru-based catalysts and ammonia as a reactant. The influence of different support materials and bimetallic catalysts is investigated for the amination of isomannide as a biogenic diol. Most importantly, the transferability of the reaction conditions to various other primary and secondary alcohols is successfully proved. Hence, water appears to be a suitable solvent for the sustainable production of biogenic amines and offers great potential for further process development.
One-Pot Preparation of Dimethyl Isosorbide from d-Sorbitol via Dimethyl Carbonate Chemistry
Aricò,Aldoshin,Tundo
, p. 53 - 57 (2017/01/17)
Direct synthesis of dimethyl isosorbide (DMI) from d-sorbitol via dimethyl carbonate (DMC) chemistry is herein first reported. High yield of DMI was achieved using the nitrogen superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst and performing the reaction in a stainless steel autoclave by increasing the temperature from 90 to 200 °C. In this procedure, DMC features its full capacity acting in the different steps of the process as carboxymethylating, leaving-group (cyclization), and methylating agent; DMC is also employed as the reaction media.
Selective Dehydration of Mannitol to Isomannide over Hβ Zeolite
Yokoyama, Haruka,Kobayashi, Hirokazu,Hasegawa, Jun-Ya,Fukuoka, Atsushi
, p. 4828 - 4834 (2017/07/24)
Isomannide is a potential feedstock for the production of super engineering plastics. A prospective route to obtain isomannide is dehydration of mannitol derived from lignocellulosic biomass, but homogeneous acid catalysts reported in the literature produce a large amount of 2,5-sorbitan as a byproduct in the dehydration reaction. In this work, we initially studied the mechanism of proton-induced dehydration of mannitol by density functional theory calculations, which suggested that local steric hindrance around acid sites designed at the angstrom level can tune the selectivity toward isomannide formation. Based on this prediction, we found that the precisely defined microporous confinement offered by Hβ provides improved selectivity and high catalytic activity for the production of isomannide, where 1,4-dehydration is favored by 20 kJ mol-1 of activation energy. The optimization of the Si/Al ratio of Hβ to balance the acid amount and hydrophobicity improved the catalytic activity and achieved 63% yield of isomannide, far exceeding the best result reported previously (35% yield).
PROCESS FOR PRODUCING ISOHEXIDES
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Paragraph 0036; 0037, (2017/12/15)
A process is described for producing an isohexide by a base catalyzed conversion of a 1,2:5,6-diacetal of a hexitol to the isohexide.
METHOD FOR PURIFYING ANHYDROUS SUGAR ALCOHOL, ANHYDROUS SUGAR ALCOHOL AND RESIN
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Paragraph 0077; 0078, (2017/01/19)
Provided are an anhydrosugar alcohol purification method, etc. with which an anhydrosugar alcohol can be efficiently purified and an anhydrosugar alcohol of excellent storage stability can be obtained, and which can limit discoloration and reduction of glass transition temperature of a resin obtained using said anhydrosugar alcohol. The anhydrosugar alcohol purification method is provided with a step for distilling an anhydrosugar alcohol from a substance to be distilled comprising active carbon and the anhydrosugar alcohol.
