535-94-4Relevant articles and documents
Ru/P-containing porous biochar-efficiently catalyzed cascade conversion of cellulose to sorbitol in water under medium-pressure H2 atmosphere
Chen, Shuainan,Fu, Zaihui,Jiang, Dabo,Liu, Yachun,Mao, Feng,Wan, Feifei,Xiong, Manman,Yang, Long,Zhang, Chao,Zhang, Qiao
supporting information, p. 1026 - 1035 (2020/09/22)
This paper discloses a simple and productive strategy for the preparation of biochar-based bifunctional catalysts. In this strategy, very cheap bamboo powder is thermally carbonized to yield P-containing porous biochars (PBCs) by the activation of concentrated phosphoric acid (H3PO4), and the latter can be transformed into the target catalysts via loading Ru nanometer particles (NPs) on them (marked as Ru/PBCs). A series of characterizations and measurements support that PBCs have stable and rich micro-meso pores and small strong acidic protons (0.100.28 mmol￠g11) attributable to the grafted and/or skeleton phosphorus groups, as well as a strong affinity to β-1,4-glycosidic bonds, thus exhibiting a good acid catalytic activity for the hydrolysis of cellulose to glucose. More importantly, they are excellent acidic supports for the loading of Ru NPs owing to high BET surface area, which can give the loaded Ru NPs uniform and narrow distribution (16 nm). The resulting bifunctional Ru/PBCs catalysts possess excellent hydrolytic hydrogenating activity for the one-pot cascade conversion of cellulose and the optimized conditions can achieve ca. 89% hexitol yield with 98% sorbitol selectivity under relatively mild conditions. This work provides a good example for the preparation of biomass-derived bifunctional catalysts and their applications in biorefinery.
Effective conversion of cellobiose and glucose to sorbitol using non-noble bimetallic NiCo/HZSM-5 catalyst
Zada, Bakht,Yan, Long,Fu, Yao
, p. 1167 - 1174 (2018/08/17)
The tandem hydrolysis and hydrogenation of saccharides into sorbitol is an especially attractive reaction in the conversion of biomass. Here, an economical and efficient bimetallic catalyst for the transformation of glucose and cellobiose into sorbitol is reported. Non-precious metal based catalysts such as NiCo, Ni, and Co, were prepared via modified impregnation method, and NiCo/HZSM-5 showed superior performance for the synthesis of sorbitol (86.9% from cellobiose, 98.6% from D-glucose). Various characterizations, such as Brunner-Emmet-Teler (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), confirmed that NiCo alloy formed and highly dispersed in NiCo/HZSM-5 catalyst. The high performance of fabricated catalyst would be attributed to the formation of nickel-cobalt alloy over HZSM-5 zeolite surface. High temperature and H2 pressure were favorable for the tandem hydrolysis and hydrogenation reaction. Besides, the reaction pathway was also proposed based on the kinetics study. Cellobitol was detected as the intermediate in the reaction mixture. Furthermore, in the catalytic stability study, it was found that active metal species of NiCo/HZSM-5 were stable. The deactivation of catalyst would be due to the covering of acidic sites over NiCo/HZSM-5.
A One-Step Synthesis of C6 Sugar Alcohols from Levoglucosan and Disaccharides Using a Ru/CMK-3 Catalyst
Yin, Wang,Tang, Zhenchen,Venderbosch, Robertus Hendrikus,Zhang, Zheng,Cannilla, Catia,Bonura, Giuseppe,Frusteri, Francesco,Heeres, Hero Jan
, p. 4411 - 4422 (2016/07/12)
Sorbitol is an important commercially available chemical with a broad application range and is typically made by the catalytic hydrogenation of glucose. Here we report a high-yield synthesis of sorbitol from levoglucosan (1,6-anhydro-β-d-glucopyranose) and cellobiose, two sugars present in pyrolysis liquids, using a mesoporous carbon-supported Ru catalyst (Ru/CMK-3). The hydrogenation reactions were performed in a batch autoclave setup under a hydrogen pressure of 50 bar and temperatures ranging from 120 to 180 °C in water. The hydrogenation of levoglucosan gave essentially quantitative yields of sugar alcohols, composed of 96.2 wt % of sorbitol and 3.8 wt % of mannitol (180 °C, 5 h). Ru/CMK-3 shows superior catalytic performance compared to a commercial Ru/C catalyst. A reaction pathway involving glucose as an intermediate and subsequent (hydrogenolysis) reactions of the desired sorbitol is proposed. Reactions with glucose and sorbitol were performed to define the reaction pathways and to highlight the differences between Ru/C and Ru/CMK-3. Disaccharides including cellobiose and sucrose were also tested, yielding up to 95 wt % of C6 sugar alcohols at 180 °C in 5 h for both substrates. Detailed catalyst characterization studies (N2 physisorption, TEM, XRD, NH3-TPD, H2-TPD) revealed that Ru/CMK-3 contains considerable amounts of strong acid sites (NH3-TPD). Catalyst stability was tested by catalyst recycling experiments using levoglucosan in batch. After three successive runs, the rate of the hydrolysis reaction of LG to glucose was about constant, though the subsequent hydrogenation reaction to sorbitol/mannitol was slightly retarded as evidenced from a slight increase in the remaining amounts of glucose at the end of reaction.
Polyoxometalate-supported ruthenium nanoparticles as bifunctional heterogeneous catalysts for the conversions of cellobiose and cellulose into sorbitol under mild conditions
Liu, Mi,Deng, Weiping,Zhang, Qinghong,Wang, Yanliang,Wang, Ye
supporting information; experimental part, p. 9717 - 9719 (2011/10/12)
Ru nanoparticles loaded on a Keggin-type polyoxometalate (Cs 3PW12O40), which did not possess strong intrinsic acidity, efficiently catalysed the conversions of cellobiose and cellulose into sorbitol in water medium in H2 at ≤433 K. The Bronsted acid sites generated in situ from H2 have been demonstrated to play a key role in the formation of sorbitol. The Royal Society of Chemistry 2011.
Conversion of cellobiose into sorbitol in neutral water medium over carbon nanotube-supported ruthenium catalysts
Deng, Weiping,Liu, Mi,Tan, Xuesong,Zhang, Qinghong,Wang, Ye
body text, p. 22 - 32 (2010/06/13)
Carbon nanotube (CNT)-supported ruthenium catalysts were studied for the hydrogenation of cellobiose in neutral water medium. The acidity of catalysts and the size of Ru particles played key roles in the conversion of cellobiose to sorbitol. A higher concentration of nitric acid used for CNT pretreatment provided a better sorbitol yield, suggesting an important role of catalyst acidity. The catalysts with larger mean sizes of Ru particles and abundant acidic sites exhibited better sorbitol yields, while those with smaller Ru particles and less acidic sites favored the formation of 3-β-d-glucopyranosyl-d-glucitol. We elucidated that cellobiose was first converted to 3-β-d-glucopyranosyl-d-glucitol via the hydrogenolysis, and then sorbitol was formed through the cleavage of β-1,4-glycosidic bond in 3-β-d-glucopyranosyl-d-glucitol over the catalysts. The catalyst with smaller Ru particles favored the first step but was disadvantageous to the second step due to the less acidity. Smaller Ru particles also accelerated the degradation of sorbitol.
Method of preparing lacitol monohydrate and dihydrate
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, (2008/06/13)
The invention relates to the new product lactitol monohydrate and to a method for the production of crystalline lactitol. The crystalline lactitol monohydrate can be obtained bij seeding an aqueous lactitol solution of a special concentration under special conditions causing the lactitol monohydrate to crystallize and recovering the product. From the mother liquor a further amount of lactitol dihydrate can be recovered. Crystalline lactitol dihydrate can be obtained using different special conditions. Lactitolmonohydrate can further be obtained by mixing one part bij weight of an aqueous lactitol solution of a suited concentration with 1 tot 3 parts bij weight of methanol or ethanol and cooling the mixture to 15° tot 25° C.
Sequential removal of monosaccharides from the reducing end of oligosaccharides and uses thereof
-
, (2008/06/13)
Methods are provided for the sequential removal of monosaccharides from the reducing end of oligosaccharides. The present invention also discloses the use of such methods for structural determinations of oligosaccharides and to enable new structures to be generated from pre-existing oligosaccharides. In addition, the methods of the present invention may be automated by the incorporation into systems.
Hydrolysis of Substrate Analogues Catalysed by β-D-Glucosidase from Aspergillus niger. Part III. Alkyl and Aryl β-D-Glucopyranosides
Sigurskjold, Bent W.,Haunstrup, Ib,Bock, Klaus
, p. 451 - 458 (2007/10/02)
The hydrolysis of eighteen alkyl and aryl β-D-glucopyranosides and the disaccharides methyl β-cellobioside (reference substrate), cellobitol, methyl β-gentiobioside, and methyl α-C-gentiobioside catalysed by β-D-glucosidase from Aspergillus niger has been studied using 1H NMR spectroscopy and progress-curve enzyme kinetics in both single-substrate and competition experiments.The influence of chain length and stereochemistry of alkyl groups and substitutions of phenyl groups revealed that this enzyme has evolved preferentially to hydrolyse cellobiose despite low aglycone specificity.The implications of steric and polar or non-polar effects, which were shown to be important for the active site interactions on the energetics of the enzymatic activity as inferred from the kinetic experiments, are discussed.
SYNTHESIS OF A CLOSE ANALOG OF THE REPEATING UNIT OF THE ANTIFREEZE GLYCOPROTEINS OF POLAR FISH
Anisuzzaman, Abul Kashem M.,Anderson, Laurens,Navia, Juan L.
, p. 265 - 278 (2007/10/02)
The protected glycopeptide N-(benzyloxycarbonyl)-L-alanyl-3)-O-(2,4,6-tri-O-benzyl-α-D-galactopyranosyl)-(1->3)>-L-threonyl-L-alanine 2,2,2-trichloroethyl ester (21) was made by coupling the respective disaccharide and tripeptide blocks.The disaccharide block was generated by coupling tetra-O-benzoyl-α-D-galactopyranosyl bromide to allyl 2,4,6-tri-O-benzyl-α-D-galactopyranoside and converting the product into O-(2,3,4,6-tetra-O-benzoyl-β-D-galactopyranosyl)-(1->3)-2,4,6-tri-O-benzyl-α-D-galactopyranosyl chloride (6) via the 1-propenyl glycoside and the free (1-OH) sugar.Alternatively, the 1-propenyl intermediate was obtained directly by using 1-propenyl 2,4,6-tri-O-benzyl-α-D-galactopyranoside (10) as the acceptor in the initial coupling reaction.An efficient 3-step synthesis of 10 was accomplished by the dibutyltin oxide-assisted, selective crotylation of allyl α-D-galactopyranoside at O-3, followed by benzylation and treatment of the product with potassium tert-butoxide.The N-benzyloxycarbonyl (Z) and N-tert-butoxycarbonyl (Boc) 2,2,2-trichloroethyl esters of Thr-Ala and Ala-Thr-Ala were formed by sequential coupling.The silver triflate-promoted glycosylation of the Z-protected dipeptide and tripeptide by 2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl chloride, and of the tripeptide by 6, proceeded with excellent α-stereoselectivity.From the disaccharide tripeptide 21, the carboxyl-deprotected and fully deproptected derivatives were prepared.
The assembly of oligosaccharides from "standardized intermediates": beta-(1----3)-linked oligomers of D-galactose.
Chowdhary,Navia,Anderson
, p. 173 - 185 (2007/10/02)
Several 2-O-benzoyl-4,6-di-O-benzyl-3-O-R-alpha-D-galactopyranosyl chlorides, designed as general precursors of beta-linked, interior D-galactopyranosyl residues in oligosaccharides, were tested in a sequential synthesis of the galactotriose beta-D-Galp-(1----3)-beta-D-Galp-(1----3)-D-Gal (19). The chlorides having R = tetrahydro-2-pyranyl and tert-butyldimethylsilyl gave excellent results, whereas those having R = 3-benzoylpropionyl and chloroacetyl were unsatisfactory. An activated disaccharide block (17), having R = 2,3-di-O-benzoyl-4,6-di-O-benzyl-beta-D-galactopyranosyl, was also prepared and tested as a glycosyl donor. The coupling of 17 to 1-propenyl 2-O-benzoyl-4,6-di-O-benzyl-alpha-D-galactopyranoside (14), in the molar ratio 1.13:1, gave 64% of a trisaccharide derivative (18) that could be converted into 19. This latter synthesis of 19 is efficient because all three galactose units are derived from 14 or its immediate precursor.
