- Photothermal strategy for the highly efficient conversion of glucose into lactic acid at low temperatures over a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide catalyst
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The conversion of carbohydrates into lactic acid has attracted increasing attention owing to the broad applications of lactic acid. However, the current methods of thermochemical conversion commonly suffer from limited selectivity or the need for harsh conditions. Herein, a light-driven system of highly selective conversion of glucose into lactic acid at low temperatures was developed. By constructing a hybrid multifunctional multi-walled carbon nanotube/layered double hydroxide composite catalyst (CNT/LDHs), the highest lactic acid yield of 88.6% with 90.0% selectivity was achieved. The performance of CNT/LDHs for lactic acid production from glucose is attributed to the following factors: (i) CNTs generate a strong heating center under irradiation, providing heat for converting glucose into lactic acid; (ii) LDHs catalyze glucose isomerization, in which the photoinduced OVs (Lewis acid) in LDHs under irradiation further improve the catalytic activity; and (iii) in a heterogeneous-homogeneous synergistically catalytic system (LDHs-OH-), OH- ions are concentrated in LDHs, forming strong base sites to catalyze subsequent cascade reactions.
- Duo, Jia,Jin, Binbin,Jin, Fangming,Shi, Xiaoyu,Wang, Tianfu,Ye, Xin,Zhong, Heng
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p. 813 - 822
(2022/02/09)
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- Biochemical characterization of a recombinant acid phosphatase from Acinetobacter baumannii
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Genomic sequence analysis of Acinetobacter baumannii revealed the presence of a putative Acid Phosphatase (AcpA; EC 3.1.3.2). A plasmid construct was made, and recombinant protein (rAcpA) was expressed in E. coli. PAGE analysis (carried out under denaturing/ reducing conditions) of nickel-affinity purified protein revealed the presence of a nearhomogeneous band of approximately 37 kDa. The identity of the 37 kDa species was verified as rAcpA by proteomic analysis with a molecular mass of 34.6 kDa from the deduced sequence. The dependence of substrate hydrolysis on pH was broad with an optimum observed at 6.0. Kinetic analysis revealed relatively high affinity for PNPP (Km = 90 μM) with Vmax, kcat, and Kcat/Km values of 19.2 pmoles s-1, 4.80 s-1(calculated on the basis of 37 kDa), and 5.30 × 104 M-1s-1, respectively. Sensitivity to a variety of reagents, i.e., detergents, reducing, and chelating agents as well as classic acid phosphatase inhibitors was examined in addition to assessment of hydrolysis of a number of phosphorylated compounds. Removal of phosphate from different phosphorylated compounds is supportive of broad, i.e., 'nonspecific' substrate specificity; although, the enzyme appears to prefer phosphotyrosine and/or peptides containing phosphotyrosine in comparison to serine and threonine. Examination of the primary sequence indicated the absence of signature sequences characteristic of Type A, B, and C nonspecific bacterial acid phosphatases.
- Smiley-Moreno, Elizabeth,Smith, Douglas,Yu, Jieh-Juen,Cao, Phuong,Arulanandam, Bernard P.,Chambers, James P.
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- Silica supported Sn catalysts with tetrahedral Sn sites for selective isomerization of glucose to fructose
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Lewis acid catalyzed isomerization of glucose to fructose is an important reaction for production of renewable chemicals. Here, we show the synthesis of an active and selective Lewis acid catalyst for this reaction by controlling Sn dispersion on SBA15. Sn loading of 1 wt. % over SBA15 (Sn/SBA15) maximized the formation of tetrahedral Sn species on the catalyst surface. Increasing the loading or changing support caused formation of SnO2 clusters which reduced fructose selectivity. A mechanism based on condensation of Sn with silanol group of SBA15 is proposed. The catalyst showed high selectivity of 93 % after 2 h with 57 % fructose yield. The Lewis acid catalyzed isomerization of glucose was proven by isotopic tracer study using D-glucose-2-d. The catalyst deactivated in the third cycle owing to byproduct deposition, but the activity was restored by recalcining the catalyst.
- Palai, Yayati Naresh,Shrotri, Abhijit,Asakawa, Miyuki,Fukuoka, Atsushi
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p. 241 - 248
(2020/04/27)
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- Sustainable production of 5-hydroxymethyl furfural from glucose for process integration with high fructose corn syrup infrastructure
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5-Hydroxymethyl furfural (HMF) is a platform chemical, which can be derived from lignocellulosic biomass, and used for production of liquid fuels and polymers. We demonstrate a process for production of HMF using sequential enzymatic and catalytic reactions of glucose to synthesize HMF, and simulated-moving-bed (SMB) separation to purify HMF. The adsorption thermodynamic parameters of glucose, fructose, and HMF on a commercial chromatography resin are experimentally determined for modeling the SMB-based HMF production process. The experimental data are used to develop a rigorous process model and then estimate the cost of production. Chromatographic separation of HMF has 16% lower operating costs compared to an extraction-based process and has a minimum selling price of approximately $1478 per ton. We demonstrate that the HMF process can be integrated with the high fructose corn syrup (HFCS) process, and we performed analyses considering two systems including construction of a new integrated facility and retrofitting an existing HFCS facility to produce HMF. Our analyses suggest that the latter approach is a promising short-term low-risk strategy to advance the HMF production technology to commercial scale.
- Bajaj, Ishan,Chang, Hochan,Dumesic, James A.,Huber, George W.,Maravelias, Christos T.,Motagamwala, Ali Hussain,Somasundaram, Arun
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p. 3277 - 3288
(2021/05/25)
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- Feruloyl sucrose derivatives from the root of Xerophyllum tenax
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A phytochemical investigation of the roots of Xerophyllum tenax led to the isolation of three undescribed feruloyl sucrose derivatives along with two known feruloyl sucrose derivatives, heloniosides A and B. This is the first report of their occurrence in the genus Xerophyllum and the family Melanthiaceae. The structures of these compounds were elucidated on the basis of chemical and spectroscopic analysis including 1D and 2D NMR and analysis of MS-MS fragmentation.
- Liu, Xueling,Atha, Daniel,Clark, Benjamin R.,Borris, Robert P.
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- Glucansucrases from lactic acid bacteria as biocatalysts for multi-ring catechol glucosylation
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Catechins are the major group of bioactive flavanols in green tea and cacao. 17 glucansucrase-active strains were identified from a set of 41 lactic acid bacteria, which were able to glucosylate (+)-catechin in a non-natural acceptor reaction. In total cell free extracts of 12 Leuconostoc and 5 Weissella strains were active on catechin and also 8 cell fractions exhibited catechin glucosylation activity. Six enzymes were selected for further evaluation and enriched up to 37 fold in yields of at least 40%. Glucansucrase of L. citreum DSM 5577 was the most efficient biocatalyst for (+)-catechin transformation with conversions of >40% after 24 h. NMR analysis of the major reaction product confirmed the (+)-catechin-4′-O-α-d-glucoside. Only L. kimchi B-65337 produced a second catechin monoglucoside. Four out of six glucansucrases glucosylated esculetin and all enzymes were active on haematoxylin. Glucansucrases of L. citreum DSM 5577, L. kimchi B-65337 and W. beninensis DSM 22752 were the best suited biocatalysts with conversions of >30% for esculetin and >60% for haematoxylin. W. beninensis DSM 22752 glucansucrase produced 89% haematoxylin glucosides without process optimization. L. kimchi B-65337 and W. beninensis DSM 22752 synthesized >40% diglucosides with the bifunctional haematoxylin. NMR analysis of the purified esculetin products confirmed formation of the 6-O-α-d- and 7-O-α-d-glucosides. Also two haematoxylin monoglucosides were identified as the 9-O-α-d- and 3-O-α-d-glucosides.
- Nolte, Johannes,Kempa, Alexander,Hochgürtel, Matthias,Sch?rken, Ulrich
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- Hydroxyapatite-Supported Polyoxometalates for the Highly Selective Aerobic Oxidation of 5-Hydroxymethylfurfural or Glucose to 2,5-Diformylfuran under Atmospheric Pressure
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(NH4)5H6PV8Mo4O40 supported on hydroxyapatite (HAP) (PMo4V8/HAP (n)) was prepared through the ion exchange of hydroxy groups. This ion exchange favored the oxidative conversion of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF) in a one-pot cascade reaction with 96.0 % conversion and 83.8 % yield under 10 mL/min of O2 flow. PMo4V8/HAP (31) was used to explore the production of DFF directly from glucose with the highest yield of 47.9 % so far under atmospheric oxygen, whereas the yield of DFF increased to 54.7 % in a one-pot and two-step reaction. These results indicated that the active sites in PMo4V8/HAP (31) retained their activities without any interference toward one another, which enabled the production of DFF in a more cost-saving way by only using oxygen and one catalyst in a one-step reaction. Meanwhile, the rigid structure of HAP and strong interaction in PMo4V8/HAP (31) allowed this catalyst to be reused for at least six times with high stability and duration.
- Guan, Hongyu,Li, Ying,Wang, Qiwen,Wang, Xiaohong,Yu, Hang
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p. 997 - 1005
(2021/08/06)
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- Few-Unit-Cell MFI Zeolite Synthesized using a Simple Di-quaternary Ammonium Structure-Directing Agent
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Synthesis of a pentasil-type zeolite with ultra-small few-unit-cell crystalline domains, which we call FDP (few-unit-cell crystalline domain pentasil), is reported. FDP is made using bis-1,5(tributyl ammonium) pentamethylene cations as structure directing agent (SDA). This di-quaternary ammonium SDA combines butyl ammonium, in place of the one commonly used for MFI synthesis, propyl ammonium, and a five-carbon nitrogen-connecting chain, in place of the six-carbon connecting chain SDAs that are known to fit well within the MFI pores. X-ray diffraction analysis and electron microscopy imaging of FDP indicate ca. 10 nm crystalline domains organized in hierarchical micro-/meso-porous aggregates exhibiting mesoscopic order with an aggregate particle size up to ca. 5 μm. Al and Sn can be incorporated into the FDP zeolite framework to produce active and selective methanol-to-hydrocarbon and glucose isomerization catalysts, respectively.
- Abeykoon, Milinda,Al-Thabaiti, Shaeel,Bell, Alexis T.,Boscoboinik, J. Anibal,Dai, Heng,Dauenhauer, Paul,Dorneles de Mello, Matheus,Duan, Xuekui,Ghosh, Supriya,Kamaluddin, Huda Sharbini,Khan, Zaheer,Kumar, Gaurav,Li, Xinyu,Lu, Peng,Luo, Tianyi,Mkhoyan, K. Andre,Narasimharao, Katabathini,Qi, Liang,Rimer, Jeffrey D.,Tsapatsis, Michael
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supporting information
p. 19214 - 19221
(2021/08/09)
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- Molecular insight into regioselectivity of transfructosylation catalyzed by GH68 levansucrase and β-fructofuranosidase
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Glycoside hydrolase family 68 (GH68) enzymes catalyze β-fructosyltransfer from sucrose to another sucrose, the so-called transfructosylation. Although regioselectivity of transfructosylation is divergent in GH68 enzymes, there is insufficient information available on the structural factor(s) involved in the selectivity. Here, we found two GH68 enzymes, β-fructofuranosidase (FFZm) and levansucrase (LSZm), encoded tandemly in the genome of Zymomonas mobilis, displayed different selectivity: FFZm catalyzed the β-(2→1)-transfructosylation (1-TF), whereas LSZm did both of 1-TF and β-(2→6)-transfructosylation (6-TF). We identified His79FFZm and Ala343FFZm and their corresponding Asn84LSZm and Ser345LSZm respectively as the structural factors for those regioselectivities. LSZm with the respective substitution of FFZm-type His and Ala for its Asn84LSZm and Ser345LSZm (N84H/S345A-LSZm) lost 6-TF and enhanced 1-TF. Conversely, the LSZm-type replacement of His79FFZm and Ala343FFZm in FFZm (H79N/A343SFFZm) almost lost 1-TF and acquired 6-TF. H79N/A343S-FFZm exhibited the selectivity like LSZm but did not produce the β-(2→6)-fructoside-linked levan and/or long levanooligosaccharides that LSZm did. We assumed Phe189LSZm to be a responsible residue for the elongation of levan chain in LSZm and mutated the corresponding Leu187FFZm in FFZm to Phe. An H79N/L187F/A343S-FFZm produced a higher quantity of long levanooligosaccharides than H79N/A343S-FFZm (or H79NFFZm), although without levan formation, suggesting that LSZm has another structural factor for levan production. We also found that FFZm generated a sucrose analog, β-D-fructofuranosyl α-D-mannopyranoside, by β-fructosyltransfer to D-mannose and regarded His79FFZm and Ala343FFZm as key residues for this acceptor specificity. In summary, this study provides insight into the structural factors of regioselectivity and acceptor specificity in transfructosylation of GH68 enzymes.
- Kikuchi, Asako,Kimura, Atsuo,Lang, Weeranuch,Okuyama, Masayuki,Sadahiro, Juri,Serizawa, Ryo,Tagami, Takayoshi,Tanuma, Masanari
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- Oxidative Conversion of Glucose to Formic Acid as a Renewable Hydrogen Source Using an Abundant Solid Base Catalyst
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Formic acid is one of the most desirable liquid hydrogen carriers. The selective production of formic acid from monosaccharides in water under mild reaction conditions using solid catalysts was investigated. Calcium oxide, an abundant solid base catalyst available from seashell or limestone by thermal decomposition, was found to be the most active of the simple oxides tested, with formic acid yields of 50 % and 66 % from glucose and xylose, respectively, in 1.4 % H2O2 aqueous solution at 343 K for 30 min. The main reaction pathway is a sequential formation of formic acid from glucose by C?C bond cleavage involving aldehyde groups in the acyclic form. The reaction also involves base-catalyzed aldose-ketose isomerization and retroaldol reaction, resulting in the formation of fructose and trioses including glyceraldehyde and dihydroxyacetone. These intermediates were further decomposed into formic acid or glycolic acid. The catalytic activity remained unchanged for further reuse by a simple post-calcination.
- Takagaki, Atsushi,Obata, Wataru,Ishihara, Tatsumi
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p. 954 - 959
(2021/07/14)
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- Promotion effect of Mg on a post-synthesized Sn-Beta zeolite for the conversion of glucose to methyl lactate
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Mg-Sn-Beta zeolites with different Mg/Sn molar ratios were prepared from the parent deAl-Beta by a coimpregnation method. The samples were characterized by powder X-ray diffraction (XRD), N2 physisorption, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy of the -OH region and probe molecule (pyridine, CD3CN and CHCl3) adsorption. The results indicate that Mg2+ and Sn4+ can react with silanol nests and incorporate into the framework of Beta zeolite. Moreover, it is relatively facile to incorporate Sn4+ into the framework. The framework metal sites generate Lewis (L) acid sites; however, the L acid strength of the framework Mg2+ is weaker than that of framework Sn4+. A small amount of Mg2+ interacts with isolated silanols to form extraframework species. Therefore, the introduction of Mg2+ results in a significant reduction in silanol defects and an increase in L acidity/basicity of Mg-Sn-Beta. Mg-Sn-Beta with Mg/Sn molar ratio of 1 has the least silanol defects. In the conversion of glucose to methyl lactate (MLA), Mg-Beta is less active than Sn-Beta due to its weaker L acidity. The TOF value for MLA formation increased in the order of Sn-Beta 0.25Mg-Sn-Beta ≈ 4Mg-Sn-Beta 1Mg-Sn-Beta, which is closely related to the amount of silanol defects in the catalysts. A kinetic study indicates that the apparent activation energy of the retro-aldol of fructose to MLA, which is the rate-determining step of glucose conversion to MLA, decreases over Mg-Sn-Beta compared to that over Sn-Beta and thus, the formation of MLA was promoted.
- Yang, Xiaomei,Lv, Bin,Lu, Tianliang,Su, Yunlai,Zhou, Lipeng
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p. 700 - 709
(2020/02/27)
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- MgO-ZrO2 Mixed Oxides as Effective and Reusable Base Catalysts for Glucose Isomerization into Fructose in Aqueous Media
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MgO-ZrO2 mixed oxides prepared with different Mg/Zr atomic ratios (denoted as xMZ: where x is the atomic ratio of Mg/Zr) are investigated for the glucose isomerization to fructose in water at 95 °C. The highest fructose yield of 33 % is obtained over 0.76MZ with ≈74 % selectivity after 3 h. To gain insight into the structure–activity relationships, the prepared catalysts are characterized by N2 physisorption, XRD, FTIR and CO2-TPD. The results indicate that the addition of MgO drastically changed the textual property of ZrO2 and increased the number of basic sites. The kinetic studies revealed that the Lewis basic sites (cus-O2?) generated from the highly dispersed MgO are the active sites responsible for the enhanced isomerization activity. Notably, MZ is reusable for four runs without a significant decrease in catalyst activity. Accordingly, this study provides an easily prepared, cheap, and recyclable catalyst that may hold great potential for fructose production.
- Rabee, Abdallah I. M.,Le, Son Dinh,Nishimura, Shun
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p. 294 - 300
(2019/12/27)
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- Solvent-Activated Hafnium-Containing Zeolites Enable Selective and Continuous Glucose–Fructose Isomerisation
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The isomerisation of glucose to fructose is a critical step towards manufacturing petroleum-free chemicals from lignocellulosic biomass. Herein we show that Hf-containing zeolites are unique catalysts for this reaction, enabling true thermodynamic equilibrium to be achieved in a single step during intensified continuous operation, which no chemical or biological catalyst has yet been able to achieve. Unprecedented single-pass yields of 58 % are observed at a fructose selectivity of 94 %, and continuous operation for over 100 hours is demonstrated. The unexpected performance of the catalyst is realised following a period of activation within the reactor, during which time interaction with the solvent generates a state of activity that is absent in the synthesised catalyst. Mechanistic studies by X-ray absorption spectroscopy, chemisorption FTIR, operando UV/Vis and 1H–13C HSQC NMR spectroscopy indicate that activity arises from isolated HfIV atoms with monofunctional acidic properties.
- Botti, Luca,Hammond, Ceri,Kondrat, Simon A.,Martinez-Espin, Juan S.,Meier, Sebastian,Navar, Ricardo,Padovan, Daniele
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supporting information
p. 20017 - 20023
(2020/09/02)
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- Gallium and tin exchanged Y zeolites for glucose isomerisation and 5-hydroxymethyl furfural production
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This study demonstrates the use of gallium and tin modified Y zeolites as catalysts for the conversion of glucose into fructose, mannose and 5-Hydroxymethyl furfural. These catalysts can be synthesised via a simple and scalable procedure that uses commercially available Y zeolite. The catalysts were characterised by various techniques including elemental analysis, electron microscopy, nitrogen physisorption, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, solid state nuclear magnetic resonance spectroscopy and X-ray absorption near edge spectroscopy. It is found that tin containing Y zeolite generate a glucose conversion of 36 % and total product yield of 17 % in water. Meanwhile, gallium containing Y zeolite shows an HMF yield of 33 % when reactions were conducted in DMSO. The recyclability of tin and gallium containing Y zeolites were studied in DMSO and the activities of both materials were shown to remain stable. Furthermore, the spent catalysts can be regenerated via calcination in air.
- Degirmenci, Volkan,Griffith, Benjamin E.,Hanna, John V.,Kilic, Emre,Oozeerally, Ryan,Pillier, John,Thompson, Paul B. J.,Walker, Marc
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- Method for preparing fructose (by machine translation)
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The method comprises the following steps: (1) reacting glucose with a catalyst in the presence of alcohol and carrying out reaction to obtain fructose-containing product; wherein the weight ratio of the glucose to the mixture of the titanium silicalite molecular sieve and the tin-silicon molecular sieve 50 - 600 is below 30 °C: (100 °C 0.1 - 6 1 1 - 10h) The method disclosed by the invention has high glucose conversion rate and fructose yield. (by machine translation)
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Paragraph 0070-0101
(2020/07/02)
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- Phytochemical and antitumor studies on Cynanchum mongolicum (Maxim.) Kom
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A chemical investigation of Cynanchum mongolicum (Maxim.) Kom. identified 8 compounds. On the basis of spectroscopic data, they were determined to be 3 alkaloids and 5 sinapoyl esters, among which were two previously undescribed compounds (1 and 2). The inhibitory effects of the isolated compounds against four human tumor cell lines were evaluated in vitro by MTT assays, which revealed moderate inhibitory effects with IC50 values 50 values 0.1 mM, which was obviously better than the 5-fluorouracil and potential to be used as cancer drugs.
- Yang, Yong-Cheng,Wang, Yan-Ming,Rong, Zi-Jian,Hong, Li-Na,Zhang, Qian,Jia, Jing-Ming,Wang, An-Hua
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p. 3437 - 3443
(2019/03/11)
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- Benzofuran and coumarin derivatives from the root of Angelica dahurica and their PPAR-γ ligand-binding activity
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A phytochemical investigation of the root of Angelica dahurica led to the isolation of benzofuran and coumarin derivatives. This is the first report of the isolation and identification of three furanocoumarin sulfates from A. dahurica root. The structures of a total of twelve undescribed compounds were determined by extensive spectroscopic analysis, including 2D NMR data, hydrolysis, and solvolysis, followed by either physicochemical and spectroscopic data or X-ray crystallographic analysis. The isolated compounds were evaluated for their PPAR-γ ligand-binding activity, and six compounds showed significant PPAR-γ ligand-binding activity. In particular, the undescribed benzofuran derivative, 3-[6,7-furano-9-hydroxy-4-(2″,3″-dihydroxy-3″-methylbutyloxy)]-phenyl propionic acid, exhibited the most potent PPAR-γ ligand-binding activity and accumulated intracellular lipid in 3T3-L1 cells.
- Matsuo, Yukiko,Yamaguchi, Emi,Hakamata, Ryo,Ootomo, Kanae,Takatori, Kazuhiro,Fukaya, Haruhiko,Mimaki, Yoshihiro
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- Inulinase immobilisation in PAA/PEG composite for efficient fructooligosaccharides production
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Inulinase was immobilised by entrapment method in polyacrylamide/polyethylene glycol composite and evaluated for its efficiency for short-chain fructooligosaccharides (3–6 degrees of polymerisation) production in batch hydrolysis system. Aqueous two-phase
- Dimitrovski, Darko,Krastanov, Albert,Temkov, Mishela,Velickova, Elena
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- PROCESSES FOR PREPARING SORBOSE FROM GLUCOSE
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Processes for converting glucose to sorbose with tailored selectivity. The processes include contacting glucose with a silica-containing structure that includes a zeolite having a topology of a 10-membered ring or smaller and Lewis acidic M4+ framework centers, wherein M is Ti, Sn, Zr, or Hf. Contacting the glucose is conducted under reaction conditions sufficient to isomerize the glucose to sorbose.
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Paragraph 0012-0013; 0016-0018; 0035-0037; 0038
(2020/08/25)
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- Bi-Functional Magnesium Silicate Catalyzed Glucose and Furfural Transformations to Renewable Chemicals
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Bio-refinery is attracting significant interest to produce a wide range of renewable chemicals and fuels from biomass that are alternative to fossil fuel derived petrochemicals. Similar to petrochemical industries, bio-refinery also depends on solid zeolite catalysts. Acid-base catalysis plays pivotal role in producing a wide range of chemicals from biomass. Herein, the Mg framework substituted MTW zeolite is synthesized and explored in the valorisation of glucose and furfural. Bi-functional (acidic and basic) characteristics are confirmed using pyridine adsorbed FT?IR analysis and NH3 and CO2 temperature-programmed desorption techniques. Textural properties and morphological information are retrieved from N2-sorption, X-ray photoelectron spectroscopy, and electron microscopy. The activity of the catalyst is demonstrated in the selective isomerisation of glucose to fructose in ethanol. Glucose is converted to methyl lactate in high yield using the same catalyst. Further, the bi-functional activity of this catalyst is demonstrated in the production of fuel precursor by the reaction of furfural and isopropanol. Mg?MTW zeolite exhibits excellent activity in the production of all these chemicals and fuel derivative. The catalyst exhibits no significant loss in the activity even after five recycles. One simple catalyst affording three renewable synthetic intermediates from glucose and furfural will attract significant attention to catalysis researchers and industrialists.
- Kumar, Abhinav,Srivastava, Rajendra
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p. 4807 - 4816
(2020/08/24)
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- Method for preparing lactic acid through catalytically converting carbohydrate
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The invention relates to a method for preparing lactic acid through catalytically converting carbohydrate, and in particular, relates to a process for preparing lactic acid by catalytically convertingcarbohydrate under hydrothermal conditions. The method disclosed by the invention is characterized by specifically comprising the following steps: 1) adding carbohydrate and a catalyst into a closedhigh-pressure reaction kettle, and then adding pure water for mixing; 2) introducing nitrogen into the high-pressure reaction kettle to discharge air, introducing nitrogen of 2 MPa, stirring and heating to 160-300 DEG C, and carrying out reaction for 10-120 minutes; 3) putting the high-pressure reaction kettle in an ice-water bath, and cooling to room temperature; and 4) filtering the solution through a microporous filtering membrane to obtain the target product. The method can realize high conversion rate of carbohydrate and high yield of lactic acid, and has the advantages of less catalyst consumption, good circularity, small corrosion to reaction equipment and the like.
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Paragraph 0029-0040
(2020/11/01)
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- Production of 5-HMF from glucose using TiO2-ZrO2 catalysts: Effect of the sol-gel synthesis additive
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Different TiO2-ZrO2 (50/50 wt%) mixed metal oxide catalysts were synthesized by the sol-gel method after varying the synthesis additive (e.g., CH3COOH, HNO3, NH4OH and NaOH) to study its effect on the production yield of 5-HMF from the conversion of glucose at 175 °C and 30 bar (Ar) (batch reaction system). Various characterization techniques such as BET, XRD, FTIR, 1HNMR, NH3-TPD, TPO, SEM and TEM were employed to study the physicochemical properties of the synthesized materials and to correlate them with the reaction product yields. Highest HMF yield (76%) was obtained over the TiO2-ZrO2-C2H4O2 catalyst in a biphasic reaction system with a glucose concentration of 2 wt% and a glucose/catalyst mass ratio of 2.5. From the NH3-TPD results, highest amount of total acid sites was observed for the TiO2-ZrO2 (50/50 wt%) prepared by the sol-gel method using the acetic acid additive, and acidity value was 3 and 2.5 times higher than that of TiO2 and ZrO2 alone, respectively. It was concluded that total acid sites density is an important parameter to obtain high 5-HMF product yields. A higher number density of sites can be obtained using the complexing additive of acetic acid in the Sol-Gel method among the other additives investigated.
- Silahua-Pavón, Adib A.,Espinosa-González, Claudia G.,Ortiz-Chi, Filiberto,Pacheco-Sosa, J. Gpe,Pérez-Vidal,Arévalo-Pérez, J. Carlos,Godavarthi, Srinivas,Torres-Torres
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- Selective Glucose-to-Fructose Isomerization in Ethanol Catalyzed by Hydrotalcites
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A combination of ethanol solvent and hydrotalcite (HT) with a Mg/Al ratio of 3:1 was effective for the isomerization of glucose to fructose in up to 56% yield with a high selectivity of 80%. The ethanol solvent shifts the isomerization equilibrium between glucose and fructose, which allows the fructose yield to exceed the upper limit of enzymatic isomerization conducted in water at modest temperatures (i.e., 50%). The HT catalyst maintained such high catalytic performance in repeated use at least three times via calcination and subsequent reconstruction of the original layered structure by the memory effect, which was operated in an aqueous solution containing ammonium carbonate. The results of catalyst screening, characterization, and isotope tracer analysis have revealed that the base sites of HT mainly contribute to its high catalytic activity for glucose-to-fructose isomerization.
- Yabushita, Mizuho,Shibayama, Natsumi,Nakajima, Kiyotaka,Fukuoka, Atsushi
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p. 2101 - 2109
(2019/03/12)
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- Utilizing imogolite nanotubes as a tunable catalytic material for the selective isomerization of glucose to fructose
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The isomerization of glucose to fructose is an important step in the conversion of biomass to valuable fuels and chemicals. A key challenge for the isomerization reaction is achieving high selectivity towards fructose using recyclable and inexpensive catalysts. In this study, the isomerization of glucose to fructose is investigated through using imogolite nanotubes as a catalyst. Imogolite is a single-walled aluminosilicate nanotube characterized by surface areas of 200-400 m2/g and pore widths near 1 nm. Imogolite is a highly tunable structure and can be modified through substitution of Si with Ge or through functionalization of methyl groups to the inner surface. These modifications change the surface properties of the nanotubes and enable tuning of the catalytic performance. Imogolite nanotubes are successfully used as a heterogeneous catalyst for the isomerization of glucose to fructose. Of the compositions tested, aluminosilicate imogolite is the most active material for the conversion of glucose, achieving a glucose conversion of 30% and a fructose selectivity of 45%. Catalyst recycling experiments reveals that organic content accumulates on the nanotubes that results in a minor reduction in conversion while maintaining similar catalytic selectivity. The catalyst can be washed with aqueous ammonia, allowing the productivity of fructose to be recovered. Overall, imogolite nanotubes are an active and tunable catalytic platform with moderate selectivity for the isomerization of glucose to fructose.
- Olson, Nathaniel,Deshpande, Nitish,Gunduz, Seval,Ozkan, Umit S.,Brunelli, Nicholas A.
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- Synergistic effect between copper and different metal oxides in the selective hydrogenolysis of glucose
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Copper catalysts have been extensively applied in saccharide hydrogenolysis for their high selectivity to C-O bond cleavage. The hydrogenolysis of glucose contains many reaction procedures, which need the synergistic effect of different active sites. A series of Cu catalysts supported on metal oxides with different surface physicochemical properties were prepared. The metal oxide supports not only influence the properties of Cu, such as dispersion and the electronic state, but also affect the activity of C-C and C-O bond cleavage in glucose. Furthermore, the coordination of a large amount of Lewis acid sites and hydrogenation sites on a Cu/γ-Al2O3 catalyst can promote C-C and C-O bond cleavage, leading to the selective conversion of glucose to glycol (selectivity of 66.6%). A Cu/MgO catalyst with a large amount of basic sites and metal sites could accelerate the retro-aldol condensation and isomerization reactions simultaneously, resulting in the main products of C2, C3, and C4 polyols. A study of the synergistic effect between other transition metals and γ-Al2O3 showed that Pd had high activity for central C-C bond cleavage in glucose. Ru provided extremely strong activity for C-C bond cleavage at the terminal of the carbon chain in glucose, with the main product being methane (selectivity of 66.4%).
- Liu, Chengwei,Zhang, Zhaonan,Zhai, Xuefeng,Wang, Xianzhou,Gui, Jianzhou,Zhang, Chenghua,Zhu, Yulei,Li, Yongwang
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p. 3733 - 3742
(2019/03/05)
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- Production of lactic acid derivatives from sugars over post-synthesized Sn-Beta zeolite promoted by WO3
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Various metal oxides were used as co-catalysts to improve the production of alkyl lactate over Sn-Beta-P. WO3 exhibited the best promotion effect. The yield of MLA increased from 25% (6.5 g L?1) over Sn-Beta-P (0.2 g) to 52% (13.4 g L?1) over WO3 (0.1 g) and Sn-Beta-P (0.1 g) at 160 °C for 5 h and 3.1 wt% of glucose concentration. MLA yield of 38% was attained even at glucose concentration of 10 wt% and the space-time yield reached 7.1 g L?1 h?1. The action mechanism of WO3 was investigated. Fine WO3 particles adsorbed on surface of Sn-Beta-P in reaction media and decreased the silanol defects of Sn-Beta-P. This promotes retro-aldol of fructose, the rate-determining step of whole reaction, thus facilitated the formation of MLA. Kinetic studies indicate that the presence of WO3 decreased the activation energy of the retro-aldol of fructose. The binary solid WO3 and Sn-Beta-P is recyclable.
- Yang, Xiaomei,Zhang, Yali,Zhou, Lipeng,Gao, Beibei,Lu, Tianliang,Su, Yunlai,Xu, Jie
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p. 285 - 291
(2019/03/21)
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- Tailoring Sn-SBA-15 properties for catalytic isomerization of glucose
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Sn-SBA-15 was prepared by different methods seeking to tailor its catalytic properties. The effect of the SBA-15 synthesis pH and Sn loading in the Sn-SBA-15 structure, porosity, and type of generated Sn species on catalyst activity towards glucose isomerization was systematically evaluated. Increasing the acid concentration and the Sn loading led to a bimodal distribution of the unit cell parameter. Surface area, pore volume, and microporosity formation was not significantly affected by the synthesis parameter, while the distribution of the large mesopores was. Indeed, the catalysts with broad size distribution presented lower TON for fructose formation compared to the ones with narrow distribution. The catalytic activity was also shown to be dependent on the nature of the solvent, and initial TOF for fructose formation increased as methanol THF GVL.
- Lorenti, Juliana P.,Scolari, Eduardo,Albuquerque, Elise M.,Fraga, Marco A.,Gallo, Jean Marcel R.
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- Frucooligosaccharides purification: Complexing simple sugars with phenylboronic acid
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Prebiotic fructooligosaccharides (FOS) are currently obtained by enzymatic reaction with fructosyltransferases (FTFs) using sucrose as both donor and acceptor. In these reactions glucose results as the most abundant by-product, arising from each fructosyl transfer event and, together with fructose, because of the inherent hydrolytic activity of the FTFs. As FOS are mainly used as prebiotic in nutraceutical foods, the reduction or total elimination of monosaccharides is required. In this work the selective elimination of monosaccharides from a synthetic FOS mixture was achieved through the selective complexation of glucose and fructose with phenyl boronic acid (PBAc) followed by ethyl-acetate extraction. The process was applied to a complex mixture of FOS obtained in an enzymatic synthesis reaction containing 40% glucose, 15.8% fructose and 35% of FOS, elimination of the sugars was achieved through 3:1 molar reactions, resulting in a levan-type FOS product with 97% purity.
- Porras-Domínguez, Jaime R.,Rodríguez-Alegría, María Elena,Miranda, Alfonso,Alvarez Berber, Laura Patricia,Edmundo, Castillo,López Munguía, Agustín
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p. 204 - 212
(2019/02/12)
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- Room temperature, near-quantitative conversion of glucose into formic acid
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Herein, a facile and efficient method was developed to selectively transform glucose into formic acid at room temperature. After parameter optimization, formic acid was obtained in an unprecedented 91.3% yield with a reaction time of 8 h in lithium hydroxide aqueous solution with hydrogen peroxide as the oxidant. The synergistic effects of the base and the oxidant promoted the glucose conversion at room temperature and enhanced the selectivity towards FA. Besides, the employed mild conditions have suppressed FA decomposition that often occurred under harsh conditions, which further improved the FA selectivity. A series of model compound tests were conducted to probe the possible intermediates based on which a plausible reaction pathway was proposed. In addition, the process is applicable to various carbohydrates such as cellobiose, starch, xylan, etc. This work opens up a simple, mild but effective method to produce FA from renewable biomass resources, which would remarkably alleviate the energy consumption, capital costs, handling risks, etc.
- Wang, Can,Chen, Xi,Qi, Man,Wu, Jianeng,G?zaydin, G?kalp,Yan, Ning,Zhong, Heng,Jin, Fangming
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p. 6089 - 6096
(2019/11/20)
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- Polyoxomolybdates catalysed cascade conversions of cellulose to glycolic acid with molecular oxygen via selective aldohexoses pathways (an epimerization and a [2+4] Retro-aldol reaction)
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Selective cascade conversion of cellulose into valuable C2 or C4 products over acid catalysts is still not fully explored because glucose-fructose isomerization followed by fructose conversions is thermodynamically easy to occur during the reaction, leading the formation of C6, C5, C3 and C1 products such as 5-hydroxymethylfurfural (HMF), levulinates, lactates, formates, and so on. In this study, phosphomolybdates (PMo) with the Keggin structure was found to promote cascade oxidation of cellulose conversion via selective aldohexoses pathways, i.e. an epimerization and a [2 + 4] retro-aldol of glucose/mannose, rather than aldo-ketohexoses routes, i.e. a glucose-fructose isomerization and a [3 + 3] retro-aldol of fructose, which produced glycolic acid (GlycA) (C2) as the main product (～50% selectivity). Either in aerobic or anaerobic state, PMo selectively catalyzed glucose epimerization into mannose at 100 °C. This behavior is completely different from that of molybdate in MoO3 which is only effective for the epimerization reaction (the Bilik reaction). In this cascade oxidation reaction, PMo was reduced into heteropoly-blue (PMored) as observed by the color change of the solution, UV-VIS and FT-IR measurements. In this case, the molecular oxygen was found to reoxidize PMored into PMo, leading the catalytic activity to be remained stable. The results shown in this study provide an insight for the catalyst development on selective synthesis of C2, C4 and/or other novel valuable chemicals from carbohydrates via the aldohexose pathways.
- Bayu, Asep,Karnjanakom, Surachai,Yoshida, Akihiro,Kusakabe, Katsuki,Abudula, Abuliti,Guan, Guoqing
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- Enzymatic hydrolysis of inulin by an immobilized extremophilic inulinase from the halophile bacterium Alkalibacillus filiformis
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Bacterial inulinases are the key enzymes in the enzymatic hydrolysis of inulin and production of fructooligosaccharides (FOSs) and high fructose syrup (HFS). An extremophilic inulinase was purified from Alkalibacillus filiformis using 80% ethanol precipitation, ultrafiltration, and Q-Sepharose anion exchange chromatography. The purified inulinase was highly active in a wide range of pH, temperature, chemical reagents, and NaCl concentrations. The enzyme immobilization on cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) was carried out by carrier binding method with covalent linkage and showed improved stability and reusability within a broad temperature and pH range, compared with the free enzyme. Using free and immobilized inulinases from A. filiformis, 122 g L?1 and 160 g L?1 fructose with 61% and 80% conversion, respectively, were obtained, with inulin as the substrate. The enzymatic properties, such as notable stability under extreme conditions, make the inulinase from A. filiformis a promising candidate for related biotechnological applications.
- Yousefi-Mokri, Mahsa,Sharafi, Ali,Rezaei, Shahla,Sadeghian-Abadi, Salar,Imanparast, Somaye,Mogharabi-Manzari, Mehdi,Amanzadeh, Yaghoub,Faramarzi, Mohammad Ali
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supporting information
(2019/07/18)
-
- Anti-cariogenic Characteristics of Rubusoside
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Streptococcus mutans plays an important role in the development of dental caries in humans by synthesizing adhesive insoluble glucans from sucrose by mutansucrase activity. To explore the anti-cariogenic characteristics of rubusoside (Ru), a natural sweetener component in Rubus suavissimus S. Lee (Rosaceae), we investigated the inhibitory effect of Ru against the activity of mutansucrase and the growth of Streptococcus mutans. Ru (50 mM) showed 97% inhibitory activity against 0.1 U/mL mutansucrase of S. mutans with 500 mM sucrose. It showed competitive inhibition with a Ki value of 1.1 ± 0.2 mM and IC50 of 2.3 mM. Its inhibition activity was due to hydrophobic and hydrogen bonding interactions based on molecular docking analysis. Ru inhibited the growth of S. mutans as a bacteriostatic agent, with MIC and MBC values of 6 mM and 8 mM, respectively. In addition, Ru showed synergistic anti-bacterial activity when it was combined with curcumin. Therefore, Ru is a natural anti-cariogenic agent with anti-mutansucrase activity and antimicrobial activity against S. mutans.
- Kim, Jeesoo,Nguyen, Thi Thanh Hanh,Jin, Juhui,Septiana, Iis,Son, Gyu-Min,Lee, Gang-Hee,Jung, You-Jin,Qureshi, Dilshad,Mok, Il Kyoon,Pal, Kunal,Yang, Soo-Yeon,Kim, Seong-Bo,Kim, Doman
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p. 282 - 287
(2019/05/27)
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- One-Pot Cascade Synthesis of (3S)-Hydroxyketones Catalyzed by Transketolase via Hydroxypyruvate Generated in Situ from d-Serine by d-Amino Acid Oxidase
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We described an efficient in situ generation of hydroxypyruvate from d-serine catalyzed by a d-amino acid oxidase from Rhodotorula gracilis. This strategy revealed an interesting alternative to the conventional chemical synthesis of hydroxypyruvate starting from toxic bromopyruvate or to the enzymatic transamination from l-serine requiring an additional substrate as amino acceptor. Hydroxypyruvate thus produced was used as donor substrate of transketolases from Escherichia coli or from Geobacillus stearothermophilus catalyzing the stereoselective formation of a carbon?carbon bond. The enzymatic cascade reaction was performed in one-pot in the presence of d-serine and appropriate aldehydes for the synthesis of valuable (3S)-hydroxyketones, which were obtained with high enantio- and diastereoselectivity and in good yield. The efficiency of the process was based on the irreversibility of both reactions allowing complete conversion of d-serine and aldehydes. (Figure presented.).
- L'enfant, Mélanie,Bruna, Felipe,Lorillière, Marion,Ocal, Nazim,Fessner, Wolf-Dieter,Pollegioni, Loredano,Charmantray, Franck,Hecquet, Laurence
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p. 2550 - 2558
(2019/04/17)
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- Anti-Influenza a virus of a new oligosaccharide citric acid derivative isolated from Vigna angularis (ohwi et ohashi. var. Dainagon) Seeds
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A new oligosaccharide citric acid derivative was isolated by hot aqueous extraction at 85 °C from Vigna angularis seeds, and it was purified using anion exchange chromatography DE-52. The structure was inferred by using UV, 1 D and 2 D NMR spectroscopy and HR-MALDI/MS, and identified as α-D-galactopyranosyl-(1→6)-α-D-galactopyranosyl-(1→6)-α-D-glucopyranosyle-(1→2)-β-D-fructofuranosyle citric acid. The isolated oligosaccharide citric acid derivative revealed promising anti-influenza A virus with 50% inhibition concentration (IC50) of 0.162 nM/mL and 50% cytotoxic dose (CC50) of >2.38 nM/mL.
- Mohammed, Magdy M. D.,Kobayashi, Nobuyuki
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p. 234 - 245
(2019/07/03)
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- Au-based bimetallic catalysts: How the synergy between two metals affects their catalytic activity
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Supported bimetallic nanoparticles are particularly attractive catalysts due to increased activity and stability compared to their monometallic counterparts. In this work, gold-based catalysts have been studied as catalysts for the selective base-free oxidation of glucose. TiO2-supported Au-Pd and Au-Cu series prepared by the sol-immobilization and precipitation-reduction methods, respectively, showed a significant synergistic effect, particularly when the theoretical weight ratio of the two metals was close to 11 (with an actual experimental bulk Au/Pd molar ratio of ca. 0.8 and ca. 0.4 for Au/Cu) in both cases. XPS analysis showed that the presence of Auδ+, Pd2+ and CuOH species played an important role in the base-free glucose oxidation.
- Sha, Jin,Paul, Sébastien,Dumeignil, Franck,Wojcieszak, Robert
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p. 29888 - 29901
(2019/10/01)
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- In vivo evaluation and atom-based 3D-QSAR studies on saponins from shells of Xanthoceras sorbifolium Bunge as anti-AD agents
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A series of oleanane type of glycosides (1–19), including nine undescribed ones (1–9), were isolated and identified from Xanthoceras sorbifolium. Subsequently, an atom-based 3D-QSAR model was constructed based on results of the in vivo anti-AD evaluation of the isolates (2–3, 10–17) and nine literature-reported anti-AD oleanane type of glycosides to clarify the structure-anti-AD activity, and under the guidance of which 19 was predicted and proved to elicit a nearly equivalent in vivo anti-AD effect as xanthoceraside and donepezil that were used as positive drugs in the Y maze and Morris water maze test.
- Chen, Gang,Cheng, Maosheng,Li, Ning,Liu, Yang,Xie, Yumeng,Yang, Lei,Zhou, Di,Zou, Libo
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- D-Tagatose manufacture through bio-oxidation of galactitol derived from waste xylose mother liquor
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In this study, the bio-oxidation of galactitol to the valuable d-tagatose is presented. This proposed strategy could start with the refined by-product of waste xylose mother liquor formed by chemical hydrogenation. Through a computationally guided enzyme screening approach, a robust polyol dehydrogenase (PdPDH) was rapidly identified from a massive number of candidates. When coupled with a water-forming NADH oxidase (StNOX) for environmentally benign cofactor regeneration, subsequent reaction optimization facilitated the complete transformation of 100 g L-1 galactitol into the desired product within 15 h, with a yield of 91% in a 2 L scale preparative reaction. Compared to the current enzymatic isomerization system, our approach avoids low conversion, high operative temperatures and by-product formation, while enabling simplified product isolation.
- Sha, Feng,Zheng, Yucong,Chen, Jiao,Chen, Kequan,Cao, Fei,Yan, Ming,Ouyang, Pingkai
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supporting information
p. 2382 - 2391
(2018/05/31)
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- Integration of Enzymatic and Heterogeneous Catalysis for One-Pot Production of Fructose from Glucose
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The search for efficient routes for the production of fructose from biomass-derived glucose is of great interest and importance, as fructose is a highly attractive substrate in the conversion of cellulosic biomass into biofuels and chemicals. In this study, a one-pot, multistep procedure involving enzyme-catalyzed oxidation of glucose at C2 and Ni/C-catalyzed hydrogenation of d-glucosone at C1 selectively gives fructose in 77 % yield. Starting from upstream substrates such as α-cellulose and starch, fructose was also generated with similar efficiency and selectivity by the combination of enzymatic and heterogeneous catalysis. This method constitutes a new means of preparing fructose from biomass-derived substrates in an efficient fashion.
- Sun, Jiankui,Li, Helong,Huang, Hongzhi,Wang, Bo,Xiao, Ling-Ping,Song, Guoyong
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p. 1157 - 1162
(2018/03/21)
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- Selective Glucose-to-Fructose Isomerization over Modified Zirconium UiO-66 in Alcohol Media
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Modulated zirconium metal–organic framework UiO-66 is shown to catalyze the isomerization of d-glucose to d-fructose in alcohol media. Fructose selectivity can change depending on solvent choice. We hypothesize that the difference in selectivity is related to a combined effect of adsorption and solvation effects, which may lead to the high formation of alkylglucosides in depletion of fructose if methanol or ethanol are used. A fructose selectivity of 72 % at 82 % glucose conversion in 1-PrOH was achieved. The reaction mechanism was investigated using nuclear magnetic resonance spectroscopy. We demonstrate that UiO-66 isomerizes glucose to fructose through an intramolecular C2–C1 hydride transfer. In addition, we show that modulated UiO-66 is a highly active and stable catalyst at the reaction conditions, showing great potential for other sugar reactions.
- de Mello, Matheus Dorneles,Tsapatsis, Michael
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p. 2417 - 2423
(2018/06/14)
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- Zeolitic Materials Including Paired Lewis Acid Catalytic Sites
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Disclosed are zeolitic materials that include a microporous crystalline framework substituted with one or more paired Lewis acid sites. Each of the one or more paired Lewis acid sites within the zeolitic material can comprise a first Lewis acid metal center and a second Lewis acid metal center. The first Lewis acid metal center and the second Lewis acid metal center can be separated by three or fewer atoms within the crystalline framework. Also provided herein are methods of making these zeolitic materials as well as methods of using these zeolitic materials as catalysts.
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Paragraph 0045; 0124
(2018/05/26)
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- A method for preparation of fructose or xylulose from biomass comprising glucose or xylose using butanol and a method for separation thereof
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The present invention relates to a preparation method of fructose or xylulose from biomass comprising glucose or xylose, and a separation method of a glucose and fructose compound and a xylose and xylulose compound. The preparation method of fructose or xylulose from biomass comprising glucose or xylose comprises: a first step of reacting biomass at a temperature of 80-150°C; and a second step of filtering glucose or xylulose crystal which is not reacted in the first step, thereby capable of easily separating remaining reactant and product from a reaction mixed solution.COPYRIGHT KIPO 2018
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Paragraph 0076-0110; 0128-0189
(2018/05/24)
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- Mechanistic Studies of the Cu(OH)+-Catalyzed Isomerization of Glucose into Fructose in Water
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The isomerization of glucose to fructose is a crucial interim step in the processing of biomass to renewable fuels and chemicals. This study investigates the copper-catalyzed glucose–fructose isomerization in water, focusing on insights into the roles of the dissolved copper species. Depending on the pH, the thermodynamic equilibrium shifted towards one or a few copper species, namely Cu2+, Cu(OH)+, and Cu(OH)2. According to thermodynamics, the highest concentration of Cu(OH)+ is at pH 5.3, at which the highest fructose yield of 16 % is achieved. The obtained fructose yields strongly correlate with the concentration of Cu(OH)+. A pH decrease of 2–3 units was observed during the reaction, resulting in the deactivation of the catalyst through hydrolysis in acidic media. Based on the results of the catalytic experiments, as well as spectroscopic and spectrometric studies, we propose Cu(OH)+ as an active Lewis-acidic species following an intramolecular 1,2-hydride shift.
- Mensah, Joel B.,Delidovich, Irina,Hausoul, Peter J. C.,Weisgerber, Laurent,Schrader, Wolfgang,Palkovits, Regina
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p. 2579 - 2586
(2018/07/31)
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- Direct speciation methods to quantify catalytically active species of AlCl3 in glucose isomerization
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While homogeneous metal halides have been shown to catalyze glucose to fructose isomerization, direct experimental evidence in support of the catalytically active species remains elusive. Here, we integrate direct speciation methods with kinetics to provide strong evidence for the active species of AlCl3 in glucose-fructose isomerization in water. We investigate the effect of Lewis (AlCl3) and Br?nsted (HCl) acids on aluminum hydrolysis and glucose conversion. We demonstrate the interplay between the acids using the Optimum Logic Inc. speciation model (OLI software). We measure aqueous aluminum species and protons through in situ and ex situ27Al quantitative nuclear magnetic resonance (qNMR) and pH measurements, respectively, and quantify aluminum nanoparticles through a combination of inductively coupled plasma-mass spectrometry (ICP-MS), dynamic light scattering (DLS), and ultrafiltration. Direct speciation measurements correlated with the glucose isomerization rate indicate that the hydrolyzed Al(iii) complex [Al(H2O)4(OH)2]1+ is the active species in glucose isomerization.
- Norton, Angela M.,Nguyen, Hannah,Xiao, Nicholas L.,Vlachos, Dionisios G.
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p. 17101 - 17109
(2018/05/28)
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- Transformation of cellulose and related carbohydrates into lactic acid with bifunctional Al(III)-Sn(II) catalysts
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The catalytic transformation of cellulose into valuable chemicals such as lactic acid under mild conditions represents a promising route for the efficient utilization of renewable biomass. Here, we report that the combination of Al(iii) and Sn(ii) cations can efficiently catalyse the conversion of cellulose and related carbohydrates into lactic acid in water. Al(iii)-Sn(ii) is the most efficient combination for lactic acid formation among the many dual cations investigated. Al(iii) and Sn(ii) with a molar ratio of 1/1 work cooperatively, providing lactic acid with yields of 90%, 81% and 65% in the conversions of fructose, glucose and cellulose, respectively. The formation of lactic acid involves a series of tandem steps including the hydrolysis of cellulose to glucose, the isomerisation of glucose to fructose, the retro-aldol fragmentation of fructose to C3 intermediates and the subsequent conversion of the C3 intermediates to lactic acid. Our experimental and computational studies suggest that Al(iii) mainly catalyses the isomerisation of glucose or the C3 intermediates, whereas Sn(ii) is primarily responsible for the retro-aldol fragmentation. The combination of the two cations enables the reaction to proceed smoothly with few side reactions, providing outstanding catalytic performances for lactic acid production from cellulose or the related carbohydrates.
- Deng, Weiping,Wang, Pan,Wang, Binju,Wang, Yanliang,Yan, Longfei,Li, Yanyun,Zhang, Qinghong,Cao, Zexing,Wang, Ye
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supporting information
p. 735 - 744
(2018/02/14)
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- Two pairs of unusual melibiose and raffinose esters from Scrophularia ningpoensis
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A pair of unusual melibiose esters (1α/1β) and a pair of unusual raffinose esters (2α/2β), were isolated from Scrophularia ningpoensis. Structures of them were established by detailed spectroscopic analyses to be 6-O-(E)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α(β)-d-glucopyranose (1α/1β) and 6-O-(E)/(Z)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α-d-glucopyranosyl-(1→2)-β-d-fructofuranose (2α/2β), respectively. All these compounds were evaluated for antifouling activity against the settlement of Balanus amphitrite larvae, along with the cytotoxic effect against the proliferation of HeLa cell lines.
- Zhang, Jun,Liang, Yan,Ip, Fanny C. F.,Ip, Nancy Y.,Liu, Ting-Ting,Zhong, Ba-Lian,Xu, Shi-Hai
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p. 255 - 262
(2017/10/05)
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- Optimization of ultrasound-assisted extraction of okra (Abelmoschus esculentus (L.) Moench) polysaccharides based on response surface methodology and antioxidant activity
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This study determined the optimal conditions for ultrasound-assisted extraction of a water-soluble polysaccharide, Raw Okra Polysaccharide, from the fruit of okra using response surface methodology. The optimal extraction temperature, extraction time and ultrasonic power were 59 °C, 30 min and 522 W, respectively, giving a yield of 10.35 ± 0.11%. ROP was further isolated, lyophilized and purified using a DEAE-Sepharose Fast Flow column and Sepharose CL-6B column, revealing three elution peaks subsequently designated ROP ?1, ?2, and ?3, respectively. Of these, ROP-2 showed the highest yield, and was therefore selected for physicochemical analysis and evaluation of antioxidant activity. Gas chromatography, fourier transform infrared spectroscopy, and high-performance liquid chromatography were used to characterize the primary structural features and molecular weight, revealing that ROP-2 is composed of glucose, mannose, galactose, arabinose, xylose, fructose, and rhamnose (molar percentages: 28.8, 12.5, 13.1, 15.9, 9.2, 13.7, and 6.8%, respectively) and has an average molecular weight of 1.92 × 105 Da. A superoxide radical scavenging assay and DPPH radical scavenging assay further revealed the significant in vitro antioxidant activity of ROP-2. These findings present an effective technique for extraction of the natural antioxidant ROP-2, warranting further analysis of its potential application in the food industry.
- Wang, Kunli,Li, Mo,Wen, Xin,Chen, Xiaosong,He, Zhengyu,Ni, Yuanying
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p. 1056 - 1063
(2018/04/12)
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- Steroidal saponins from the rhizome of Polygonatum sibiricum
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Four new steroidal saponins, 3-O-β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl -(25R)-spirost-5-en-3β,17α-diol (1), 3-O-β-D-glucopyranosyl(1→4)-β-D- fucopyranosyl-(25S)-spirost-5-en-3β,17α-diol (2), 3-O-β-D-glucopyranosyl(1→2) -β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl-(25R)-spirost-5-en-3β,17α-diol (3), 3-O-β-D-glucopyranosyl(1→4)-β-D-fucopyranosyl-(25R/S)-spirost-5-en-3β,12β-diol (4), together with five known steroidal saponins were isolated from the ethanolic extract of the rhizome of Polygonatum sibiricum. Chemical structures of these compounds were elucidated by spectroscopic techniques. Anti-inflammatory activities of these new compounds were evaluated.
- Tang, Cheng,Yu, Ya-Ming,Qi, Qing-Ling,Wu, Xiao-Dan,Wang, Jia,Tang, Sheng-An
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- Role of the Strong Lewis Base Sites on Glucose Hydrogenolysis
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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
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p. 3845 - 3853
(2018/07/31)
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- Glucose Isomerization Using Alkali Metal and Alkaline Earth Metal Titanates
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Glucose isomerization was performed using various titanate catalysts, which include SrTiO3, BaTiO3, CaTiO3, Na2Ti6O13, K2Ti6O13, and Sr3Ti2O7, prepared using a conventional solid-phase method. Among the titanates, SrTiO3, CaTiO3, and Na2Ti6O13 offered a relatively high fructose yield (32 %) with a high selectivity (68–78 %). The yields are comparable to yields reported previously using a Sn-modified BEA zeolite, which shows a high efficiency for glucose isomerization as a Lewis acid catalyst. A study of the mechanism of glucose isomerization on a SrTiO3 catalyst surface by using 1H NMR spectroscopy suggested that the titanates catalyze the isomerization as base catalysts. Thus, the effect of the basicity of the titanates on glucose isomerization was investigated in terms of the base quantity and strength. The analysis was performed by using an acid–base titration method and FTIR spectroscopy with CHCl3 as a probe molecule. It is proposed that glucose isomerization on the titanates depends not only on the base amount but also on the base strength.
- Ohyama, Junya,Zhang, Yutong,Ito, Jun,Satsuma, Atsushi
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p. 2864 - 2868
(2017/07/28)
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- Chemical method of preparing fructose from glucose
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The invention relates to a simple chemical preparation method of preparing fructose from glucose. Under one atmospheric pressure and at a low temperature, one or more of phenol compounds such as p-methoxy phenol, p-chlorophenol, nitrophenol, and the like, is taken as the catalyst to catalyze glucose into fructose. The operation method is simple, the reaction conditions are mild, the cost is low, the yield of fructose is as high as 50%, by product is barely produced, and the selectivity is greater than 96%.
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Paragraph 0012; 0013; 0014; 0015; 0016; 0017; 0018-0022
(2017/08/29)
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