24 results on '"Guoyong Song"'
Search Results
2. Silver-Catalyzed Remote C5–H Selenylation of Indoles
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Wei-Hong Song, Jia Shi, Xiaohong Chen, and Guoyong Song
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Indole test ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Surface modification ,010402 general chemistry ,Selectivity ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Catalysis - Abstract
Remote C-H functionalization at C5 is the most sparingly observed selectivity in the functionalization of indole templates. Herein, we reported that the combination of a AgSbF6 catalyst and phenyliodine diacetate oxidation enabled the C-H selenylation at the C5 position of indole scaffolds in a selective version, thus leading to the formation of a wide scope of 5-selenylated indole derivatives, which are otherwise difficult to prepare. Mechanistic studies indicated that current transformation follows a radical process, and the tethered C3 pivaloyl group on indole scaffolds plays roles in both blocking the active C3 position and manipulating the electronic affinity of the arenes.
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- 2020
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3. Ru-Catalyzed Hydrogenolysis of Lignin: Base-Dependent Tunability of Monomeric Phenols and Mechanistic Study
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Helong Li and Guoyong Song
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chemistry.chemical_classification ,Base (chemistry) ,010405 organic chemistry ,Depolymerization ,fungi ,technology, industry, and agriculture ,food and beverages ,macromolecular substances ,General Chemistry ,010402 general chemistry ,complex mixtures ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Monomer ,chemistry ,Hydrogenolysis ,Lignin ,Organic chemistry ,Phenols - Abstract
Substantial attention has been given to depolymerization of lignin into monomeric phenols in recent years because lignin is a renewable and CO2-netural aromatic resource. Recent results indicated t...
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- 2019
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4. Fragmentation of Woody Lignocellulose into Primary Monolignols and Their Derivatives
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Helong Li, Xuan Guo, Guoyong Song, Jiankui Sun, Ling-Ping Xiao, Yunming Fang, and Run-Cang Sun
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Plant growth ,Primary (chemistry) ,Renewable Energy, Sustainability and the Environment ,Chemistry ,General Chemical Engineering ,Radical polymerization ,Biomass ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Environmental Chemistry ,Organic chemistry ,Lignin ,Monolignol ,Fragmentation (cell biology) ,0210 nano-technology - Abstract
Lignin, which is biosynthesized through oxidative radical polymerization from primary monolignols during plant growth, represents the most abundant source of renewable aromatic resources. The searc...
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- 2019
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5. Selective hydrogenolysis of catechyl lignin into propenylcatechol over an atomically dispersed ruthenium catalyst
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Guoyong Song, Kaili Zhang, Shuizhong Wang, Ling-Ping Xiao, and Helong Li
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Science ,Catechols ,General Physics and Astronomy ,engineering.material ,010402 general chemistry ,Lignin ,01 natural sciences ,Catalysis ,Ruthenium ,Article ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,Biopolymers ,Hydrogenolysis ,Dehydrogenation ,Heterogeneous catalysis ,Catechol ,Multidisciplinary ,010405 organic chemistry ,Depolymerization ,General Chemistry ,Combinatorial chemistry ,0104 chemical sciences ,Sustainability ,chemistry ,engineering ,Biopolymer ,Selectivity - Abstract
C-lignin is a homo-biopolymer, being made up of caffeyl alcohol exclusively. There is significant interest in developing efficient and selective catalyst for depolymerization of C-lignin, as it represents an ideal feedstock for producing catechol derivatives. Here we report an atomically dispersed Ru catalyst, which can serve as an efficient catalyst for the hydrogenolysis of C-lignin via the cleavage of C−O bonds in benzodioxane linkages, giving catechols in high yields with TONs up to 345. A unique selectivity to propenylcatechol (77%) is obtained, which is otherwise hard to achieve, because this catalyst is capable of hydrogenolysis rather than hydrogenation. This catalyst also demonstrates good reusability in C-lignin depolymerization. Detailed investigations by model compounds concluded that the pathways involving dehydration and/or dehydrogenation reactions are incompatible routes; we deduced that caffeyl alcohol generated via concurrent C−O bonds cleavage of benzodioxane unit may act as an intermediate in the C-lignin hydrogenolysis. Current demonstration validates that atomically dispersed metals can not only catalyze small molecules reactions, but also drive the transformation of abundant and renewable biopolymer., C-lignin represents an ideal feedstock for producing catechol derivatives. Here, the authors engineered an atomically dispersed Ru catalyst, which can cleave C−O bonds efficiently and circumvent C=C bonds hydrogenation selectively, thus leading to propenylcatechol in high yields with high TONs.
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- 2021
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6. Chemodivergent hydrogenolysis of eucalyptus lignin with Ni@ZIF-8 catalyst
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Liu Xue, Helong Li, Run-Cang Sun, Guoyong Song, and Ling-Ping Xiao
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010405 organic chemistry ,Chemistry ,Depolymerization ,Pulp (paper) ,food and beverages ,Biomass ,Lignocellulosic biomass ,engineering.material ,010402 general chemistry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Hydrogenolysis ,visual_art ,engineering ,visual_art.visual_art_medium ,Environmental Chemistry ,Lignin ,Organic chemistry ,Sawdust - Abstract
Reductive catalytic fractionation (RCF) of lignocellulosic biomass, that is depolymerization of the native lignin component into well-defined monomeric phenols in the first step, offers an opportunity to utilize entire biomass components. Herein, we report that Ni@ZIF-8 can serve as a chemodivergent catalyst in RCF of eucalyptus sawdust, thus selectively producing phenolic compounds having either a propyl or propanol end-chain under different reaction conditions. In both cases, high yields of lignin monomers and a high degree of delignification were achieved, next to well-preserved carbohydrate pulp suitable for further processing. A mechanistic study using model compounds indicated that the dehydroxylation at the γ-position of the β-O-4 structure may be involved in the selectivity-controlling step.
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- 2019
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7. Hydrogenolysis of biorefinery corncob lignin into aromatic phenols over activated carbon-supported nickel
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Wa Gao, Guoyong Song, Ling-Ping Xiao, Shuizhong Wang, Run-Cang Sun, and Jia Shi
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chemistry.chemical_classification ,010405 organic chemistry ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,Corncob ,010402 general chemistry ,Biorefinery ,Hydroxycinnamic acid ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Hydrogenolysis ,medicine ,Lignin ,Organic chemistry ,Phenols ,Activated carbon ,medicine.drug - Abstract
Lignin is the most abundant renewable resource for production of bio-aromatic chemicals. However, the catalytic depolymerisation of lignin into phenolic monomers is still challenging due to its intrinsic heterogeneity. Herein, we report that Ni/AC can serve as an efficient and stable catalyst in the hydrogenolysis of biorefinery corncob lignin into low-molecular-weight aromatics. This catalyst showed high activity towards reductive fragmentation of hydroxycinnamic esters and β-O-4 linkages through scission by reaction with hydrogen to cleave C–O bonds. Under optimal conditions, this catalytic system produced 31% selectivity towards unsaturated substituents containing coumarate and ferulate derivatives, which afforded mono-aromatic phenols (up to 12.1 wt%) derived from hydroxycinnamic acid moieties (8.1 wt%) and β-O-4 units (2.7 wt%), respectively. The use of non-precious metals to develop highly efficient heterogeneous catalysts makes this approach of great interest in the production of aromatic phenols for the valorisation of industrial lignin.
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- 2019
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8. Catalytic Conversion of Carbohydrates into 5-Ethoxymethylfurfural by a Magnetic Solid Acid Using γ-Valerolactone as a Co-Solvent
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Shihao Su, Run-Cang Sun, Ling-Ping Xiao, Yuan-Yuan Bai, Shuizhong Wang, Bo Wang, and Guoyong Song
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Valerolactone ,Hydrothermal carbonization ,General Energy ,010405 organic chemistry ,Biofuel ,Chemistry ,Organic chemistry ,Solid acid ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Co solvent - Published
- 2018
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9. Rhodium(III)-Catalyzed Synthesis of Cinnolinium Salts from Azobenzenes and Diazo Compounds
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Guoyong Song, Xingwei Li, Xiaohong Chen, and Guangfan Zheng
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chemistry.chemical_compound ,chemistry ,010405 organic chemistry ,Organic Chemistry ,Polymer chemistry ,chemistry.chemical_element ,Diazo ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Rhodium - Published
- 2018
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10. Selective Fragmentation of Biorefinery Corncob Lignin into p ‐Hydroxycinnamic Esters with a Supported Zinc Molybdate Catalyst
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Helong Li, Run-Cang Sun, Guoyong Song, Ling-Ping Xiao, Shuizhong Wang, and Wa Gao
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010405 organic chemistry ,General Chemical Engineering ,Corncob ,010402 general chemistry ,Biorefinery ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Solvent ,chemistry.chemical_compound ,General Energy ,Monomer ,chemistry ,law ,Environmental Chemistry ,Lignin ,Organic chemistry ,General Materials Science ,Calcination ,Selectivity - Abstract
Lignin is the largest renewable resource of bioaromatics, and the catalytic fragmentation of lignin into phenolic monomers is increasingly recognized as an important starting point for lignin valorization. Herein, we report that ZnMoO4 supported on MCM-41 can catalyze the fragmentation of biorefinery technical lignin, enzymatic mild acidolysis lignin, and native lignin derived from corncob to yield lignin oily products that contain 15-37.8 wt % phenolic monomers, in which the high selectivities towards methyl coumarate (1) and methyl ferulate (2) were obtained (up to 78 %). The effects of some key parameters such as the influence of the solvent, reaction temperature, time, H2 pressure, and catalyst dosage were examined in view of activity and selectivity. The loss of Zn from the catalyst is discussed as the primary cause of deactivation, and the catalytic activity and selectivity can be well preserved in at least six runs by thermal calcination. The high selectivity to 1 and 2 leads to their easy separation and purification from lignin oily product to provide sustainable monomers for the preparation of functional polyether esters and polyesters.
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- 2018
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11. Highly Efficient Hydrogenation of Levulinic Acid into γ-Valerolactone using an Iron Pincer Complex
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Guoyong Song, Bo Wang, Yuxuan Yi, Ling-Ping Xiao, and Huiying Liu
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Valerolactone ,Aqueous solution ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,Methyl levulinate ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Pincer movement ,Turnover number ,Catalysis ,chemistry.chemical_compound ,General Energy ,Levulinic acid ,Environmental Chemistry ,Organic chemistry ,General Materials Science ,Iron complex - Abstract
The search for nonprecious-metal-based catalysts for the synthesis of γ-valerolactone (GVL) through hydrogenation of levulinic acid and its derivatives in an efficient fashion is of great interest and importance, as GVL is an important a sustainable liquid. We herein report a pincer iron complex that can efficiently catalyze the hydrogenation of levulinic acid and methyl levulinate into GVL, achieving a turnover number of up to 23 000 and a turnover frequency of 1917 h-1 . This iron-based catalyst also enabled the formation of GVL from various biomass-derived carbohydrates in aqueous solution, thus paving a new way toward a renewable chemical industry.
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- 2018
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12. Catalytic hydrogenolysis of castor seeds C-lignin in deep eutectic solvents
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Guoyong Song, Chunquan Liu, Bo Wang, and Shuizhong Wang
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0106 biological sciences ,Catechol ,010405 organic chemistry ,Depolymerization ,fungi ,technology, industry, and agriculture ,food and beverages ,macromolecular substances ,Production efficiency ,complex mixtures ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Monomer ,chemistry ,Hydrogenolysis ,Organic chemistry ,Lignin ,Agronomy and Crop Science ,010606 plant biology & botany ,Eutectic system - Abstract
The recently discovered catechyl lignin (C-lignin) represents an ideal lignin platform for depolymerization because of its exclusive benzodioxane linkages between caffeyl alcohol monolignols. In this report, we described catalytic hydrogenolysis of castor seed coats by using deep eutectic solvents, where naturally grown C-lignin was extracted from endocarp matrix and depolymerized into monomeric catechols. The production efficiency of catechols from present one-pot manner was comparable to that from a two-step approach. High selectivity towards 4-propyl catechol was observed in DESs reactions, which was complementary to previous reports. This study offered a step-efficient protocol for producing a single, valuable catechol compound from bulk sustainable castor seed coats.
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- 2021
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13. Catalytic Hydrogenolysis of Lignins into Phenolic Compounds over Carbon Nanotube Supported Molybdenum Oxide
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Shuizhong Wang, Helong Li, Liang Xiao, Ling-Ping Xiao, Zhengjun Shi, Zhaowei Li, Run-Cang Sun, Yunming Fang, and Guoyong Song
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chemistry.chemical_classification ,Double bond ,010405 organic chemistry ,Depolymerization ,Substituent ,food and beverages ,Lignocellulosic biomass ,General Chemistry ,010402 general chemistry ,Heterogeneous catalysis ,01 natural sciences ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Hydrogenolysis ,Lignin ,Organic chemistry - Abstract
Lignin represents the most abundant source of renewable aromatic resources, and the depolymerization of lignin has been identified as a prominent challenge to produce low-molecular-mass aromatic chemicals. Herein, we report a nanostructured MoOx/CNT, which can serve as an efficient catalyst in hydrogenolysis of enzymatic mild acidolysis lignins (EMALs) derived from various lignocellulosic biomass, thus giving monomeric phenols in high yields (up to 47 wt %). This catalyst showed high selectivity toward phenolic compounds having an unsaturated substituent, because the cleavage of C–O bonds in β-O-4 units is prior to reduction of double bonds by MoOx/CNT under a H2 atmosphere, which was confirmed by examination of lignin model compound reactions. The effects of some key parameters such as the influence of solvent, temperature, reaction time, and catalyst recyclability were also examined in view of monomer yields and average molecular weight. This method constitutes an economically responsible pathway for li...
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- 2017
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14. Enantioselective C–H Annulation of Indoles with Diazo Compounds through a Chiral Rh(III) Catalyst
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Guoyong Song, Bo Wang, Helong Li, Shujing Yang, and Xiaohong Chen
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Indole test ,Annulation ,010405 organic chemistry ,Enantioselective synthesis ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Acceptor ,Medicinal chemistry ,Catalysis ,0104 chemical sciences ,Rhodium ,Stereocenter ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Diazo - Abstract
The asymmetric C–H annulation of O-pivaloyl 1-indolehydroxamic acid with donor/acceptor diazo compounds has been achieved for the first time, to the best of our knowledge, by using a rhodium catalyst embedded in a chiral binaphthyl backbone. This protocol constitutes a straightforward route for the synthesis of a new family of 1,2-dihydro-3H-imidazo[1,5-a]indol-3-one derivatives having a quaternary carbon stereocenter in high yields and excellent enantioselectivity (up to 98:2 er).
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- 2017
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15. Total utilization of lignin and carbohydrates in Eucalyptus grandis: an integrated biorefinery strategy towards phenolics, levulinic acid, and furfural
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Chen Xue, Guoyong Song, Ling-Ping Xiao, Kaili Zhang, and Run-Cang Sun
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lcsh:Biotechnology ,Lignocellulosic biomass ,Management, Monitoring, Policy and Law ,engineering.material ,010402 general chemistry ,Furfural ,01 natural sciences ,Applied Microbiology and Biotechnology ,lcsh:Fuel ,chemistry.chemical_compound ,lcsh:TP315-360 ,lcsh:TP248.13-248.65 ,Levulinic acid ,Reductive catalytic fractionation ,Lignin ,Hemicellulose ,Cellulose ,Phenolic monomers ,Platform chemicals ,Eucalyptus ,010405 organic chemistry ,Renewable Energy, Sustainability and the Environment ,Pulp (paper) ,Research ,Pulp and paper industry ,Biorefinery ,0104 chemical sciences ,General Energy ,chemistry ,engineering ,Biotechnology - Abstract
Background Lignocellulosic biomass, which is composed of cellulose, hemicellulose and lignin, represents the most abundant renewable carbon source with significant potential for the production of sustainable chemicals and fuels. Current biorefineries focus on cellulose and hemicellulose valorization, whereas lignin is treated as a waste product and is burned to supply energy to the biorefineries. The depolymerization of lignin into well-defined mono-aromatic chemicals suitable for downstream processing is recognized increasingly as an important starting point for lignin valorization. In this study, conversion of all three components of Eucalyptus grandis into the corresponding monomeric chemicals was investigated using solid and acidic catalyst in sequence. Results Lignin was depolymerized into well-defined monomeric phenols in the first step using a Pd/C catalyst. The maximum phenolic monomers yield of 49.8 wt% was achieved at 240 °C for 4 h under 30 atm H2. In the monomers, 4-propanol guaiacol (12.9 wt%) and 4-propanol syringol (31.9 wt%) were identified as the two major phenolic products with 90% selectivity. High retention of cellulose and hemicellulose pulp was also obtained, which was treated with FeCl3 catalyst to attain 5-hydroxymethylfurfural, levulinic acid and furfural simultaneously. The optimal reaction condition for the co-conversion of hemicellulose and cellulose was established as 190 °C and 100 min, from which furfural and levulinic acid were obtained in 55.9% and 73.6% yields, respectively. Ultimately, 54% of Eucalyptus sawdust can be converted into well-defined chemicals under such an integrated biorefinery method. Conclusions A two-step process (reductive catalytic fractionation followed by FeCl3 catalysis) allows the fractionation of all the three biopolymers (cellulose, hemicellulose, and lignin) in Eucalyptus biomass, which provides a promising strategy to make high-value chemicals from sustainable biomass.
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- 2020
16. From lignin subunits to aggregates: insights into lignin solubilization
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Ling-Ping Xiao, Wenwen Zhao, Lilin He, Gang Cheng, Run-Cang Sun, Blake A. Simmons, Guoyong Song, and Seema Singh
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Chemistry ,Hydrogen bond ,Intermolecular force ,02 engineering and technology ,Corncob ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Branching (polymer chemistry) ,01 natural sciences ,Pollution ,Small-angle neutron scattering ,0104 chemical sciences ,chemistry.chemical_compound ,Solubilization ,Environmental Chemistry ,Lignin ,Organic chemistry ,0210 nano-technology ,Spectroscopy - Abstract
A fundamental understanding of lignin solubilization offers structural information that would benefit a variety of value added applications. Small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) spectroscopy were used to study correlations between the functional groups/substructures and solution structures of lignin in DMSO-d6 and 0.1 N NaOD. Three types of alkaline lignins (Sigma-Aldrich kraft lignin, poplar wood kraft lignin, and corncob soda lignin), exhibiting different degrees of aggregation in 0.4 wt% solutions, were investigated to identify the major intermolecular interactions that cause lignin aggregation. Intermolecular hydrogen bonding, non-covalent π–π interactions between phenyl rings, lignin chain conformation and the degree of branching were discussed. Different operating forces for lignin solubilization and aggregation were found in DMSO-d6 and NaOD solutions.
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- 2017
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17. Acceptorless dehydrogenation and dehydrogenative coupling of alcohols catalysed by protic NHC ruthenium complexes
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Weihong Chang, Shuizhong Wang, Ling-Ping Xiao, Guoyong Song, and Xue Gong
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010405 organic chemistry ,education ,Organic Chemistry ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Catalysis ,Ruthenium ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Moiety ,Imidazole ,Organic chemistry ,Dehydrogenation ,Physical and Theoretical Chemistry - Abstract
A new family of protic NHC Ru complexes ligated with a phosphine-tethered imidazole moiety were prepared, which can act as excellent catalysts for acceptorless dehydrogenation of secondary alcohols and dehydrogenative coupling of primary and secondary alcohols, thus leading to the formation of a variety of carbonyl compounds with release of H2.
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- 2017
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18. Chemosynthesis, characterization and application of lignin-based flocculants with tunable performance prepared by short-wavelength ultraviolet initiation
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Han-Min Wang, Lu Zheng, Guoyong Song, Quentin Shi, Dan Sun, Tong-Qi Yuan, Shuangfei Wang, Run-Cang Sun, and Bin Wang
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0106 biological sciences ,Flocculation ,010405 organic chemistry ,Sterilization (microbiology) ,Raw material ,01 natural sciences ,Chloride ,0104 chemical sciences ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Wastewater ,Ultraviolet light ,medicine ,Lignin ,Turbidity ,Agronomy and Crop Science ,010606 plant biology & botany ,medicine.drug - Abstract
The high value utilization of lignin is facing sheer challenge, and the use of lignin as a raw material to prepare flocculants is of tremendous significance for wastewater treatment. In this study, lignin-based flocculants (LBFs) with tunable performances were prepared by mild copolymerization of lignosulfonate and [2-(Methacryloyloxy) ethyl] trimethylammonium chloride solution (METAC) under short-wavelength ultraviolet light. The effect of preparation conditions on the product performances was investigated, and two classes of LBFs were obtained in the same system by adjusting the preparation conditions. As compared with the preparation of LBFs suitable for simulated dye wastewater, higher monomer dose and lower pH were required for the preparation of LBFs suitable for kaolin and E. coli suspensions. Among them, LBF-1 could remove more than 95 % dye, and LBF-2 had 99.2 % and 97.5 % turbidity and bacterial removal rates, respectively. Moreover, the effects of external factors such as the LBF-1 dose, initial concentration of dye and wastewater pH on the decolorization efficiency were also explored. In addition, the sterilization function of LBF was studied, and LBF-2 experienced a process of first flocculation followed by sterilization. Furthermore, the flocculation mechanisms of LBFs in treating three kinds of wastewaters were discussed in detail.
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- 2020
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19. ortho-Selective C–H addition of N,N-dimethyl anilines to alkenes by a yttrium catalyst
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Guoyong Song, Gen Luo, Juzo Oyamada, Yi Luo, and Zhaomin Hou
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inorganic chemicals ,chemistry.chemical_classification ,010405 organic chemistry ,Cationic polymerization ,chemistry.chemical_element ,General Chemistry ,Yttrium ,010402 general chemistry ,Metathesis ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Aniline ,chemistry ,Intramolecular force ,Organic chemistry ,Alkyl - Abstract
The efficient and selective ortho-alkylation of N,N-dimethyl anilines via C–H addition to alkenes was achieved for the first time using a cationic half-sandwich yttrium catalyst. This protocol constitutes a straightforward and atom-economical route for the synthesis of a new family of tertiary aniline derivatives with branched alkyl substituents, which are otherwise difficult to obtain. DFT calculation studies suggest that the interaction between the yttrium atom and the NMe2 group plays an important role and the intramolecular C–H activation through a σ-bond metathesis pathway is the rate-determining step, which is consistent with the experimental KIE observations.
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- 2016
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20. Rhodium-Catalyzed Site-Selective Coupling of Indoles with Diazo Esters: C4-Alkylation versus C2-Annulation
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Xiaohong Chen, Guoyong Song, Yunyun Li, Xingwei Li, and Guangfan Zheng
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Annulation ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,chemistry.chemical_element ,Alkylation ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,0104 chemical sciences ,Rhodium ,Catalysis ,Coupling (electronics) ,chemistry.chemical_compound ,Site selective ,Organic chemistry ,Diazo ,Physical and Theoretical Chemistry ,Selectivity - Abstract
A Rh(III)-catalyzed site-selective C–H activation of C(3)-functionalized indoles in a coupling with diazo esters has been realized with carbonyl as a weakly coordinating group. The coupling selectivity is dictated by the temperature and additives, affording either C4-alkylated indoles or C2-annulated lactones in moderate to excellent efficiency.
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- 2017
21. Heteroatom-assisted olefin polymerization by rare-earth metal catalysts
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Yi Luo, Masayoshi Nishiura, Gen Luo, Guoyong Song, Zhaomin Hou, Chunxiang Wang, and Atsushi Yamamoto
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Multidisciplinary ,Ethylene ,010405 organic chemistry ,Chemistry ,Heteroatom ,Organic Chemistry ,SciAdv r-articles ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Monomer ,Polymerization ,Polymer chemistry ,Physical Sciences ,Copolymer ,Olefin polymerization ,Metal catalyst ,Research Articles ,Research Article - Abstract
Heteroatoms enhance polymerization and copolymerization of functional olefins., Heteroatom-functionalized polyolefins are of fundamental interest and practical importance. This has spurred investigations of the copolymerization of polar and nonpolar olefins. We report the first syndiospecific polymerization of a series of heteroatom-containing α-olefins and their copolymerization with ethylene catalyzed by half-sandwich rare-earth complexes. We have found that the interaction between a heteroatom in a functional α-olefin monomer and a rare-earth metal catalyst can significantly raise the olefin polymerization activity and thereby promote its copolymerization with ethylene. By using this heteroatom-assisted olefin polymerization (HOP) strategy, we have successfully synthesized a series of heteroatom (O, S, Se, N, and P)–functionalized polyolefins with high molecular weights and controllable functional monomer contents. The mechanistic aspect of the HOP process has been elucidated by computational studies. We expect that our findings will guide the design of new catalyst systems for the synthesis of various desired functional polyolefins.
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- 2017
22. Sequential utilization of bamboo biomass through reductive catalytic fractionation of lignin
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Run-Cang Sun, Ling-Ping Xiao, Guoyong Song, Kaili Zhang, Bo Wang, and Helong Li
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0106 biological sciences ,Bamboo ,Environmental Engineering ,Syringol ,Bioengineering ,Fractionation ,Chemical Fractionation ,010501 environmental sciences ,Xylose ,Lignin ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,010608 biotechnology ,Organic chemistry ,Hemicellulose ,Biomass ,Cellulose ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Renewable Energy, Sustainability and the Environment ,General Medicine ,chemistry ,Guaiacol - Abstract
Reductive catalytic fractionation (RCF) has emerged as a new biorefinery paradigm for the fractionation and sequential utilization of entire components of biomass. Herein, we investigated the RCF of bamboo, a highly abundant herbaceous feedstock, in the presence of Pd/C catalyst. The lignin fraction in bamboo was preferentially depolymerized into well-defined low-molecular-weight phenols, with leaving carbohydrates pulp as a solid residue. In the soluble fraction, four major phenolic compounds, e.g., methyl coumarate/ferulate derived from hydroxycinnamic units and propanol guaiacol/syringol derived from β-O-4 units, were generated up to 41.7 wt% yield based on original lignin content. In the insoluble fraction, the carbohydrates of bamboo were recovered with high retentions of cellulose (68%) and hemicellulose (49%), which upon treatment with enzyme gave glucose (90%) and xylose (85%). Overall, the three major components of bamboo could efficient to be fractionated and converted into useful platform chemicals on the basis of this study.
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- 2019
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23. Effect of Hydrothermal Processing on Hemicellulose Structure
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Ling-Ping Xiao, Guoyong Song, and Run-Cang Sun
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0106 biological sciences ,chemistry.chemical_classification ,020209 energy ,Lignocellulosic biomass ,Pentose ,02 engineering and technology ,Xylose ,Biorefinery ,Furfural ,01 natural sciences ,Hydrothermal circulation ,chemistry.chemical_compound ,chemistry ,010608 biotechnology ,0202 electrical engineering, electronic engineering, information engineering ,Levulinic acid ,Organic chemistry ,Hemicellulose - Abstract
Hydrothermal process is a potential technology to convert lignocellulosic resources into biofuels and value-added chemicals in a green fashion. Fractionation of woody biomass allows the exploration of the concept of integrated forestry biorefinery. The hydrolysis of hemicellulose produces oligosaccharides, pentose (xylose and arabinose), hexose (glucose, mannose, and galactose), acids (acetic acid, formic acid, and levulinic acid), and furans (furfural and 5-hydroxymethylfurfural), as well as resulting insoluble humins as by-products under harsh conditions. This chapter highlights recent results on hydrothermal processing of various lignocellulosic biomasses, including fundamentals of hydrothermal pretreatment and mechanistic and kinetic studies in such process, especially in analysis and characterization of hemicelluloses before and after hydrothermal processing.
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- 2017
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24. Serpentine Ni3 Ge2 O5 (OH)4 Nanosheets with Tailored Layers and Size for Efficient Oxygen Evolution Reactions
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Guoyong Song, Baopeng Yang, Renzhi Ma, Shishir Venkatesh, Min Liu, Yuanqing He, Xiaohe Liu, Yulu He, Shuquan Liang, Ning Zhang, Anqiang Pan, Vellaisamy A. L. Roy, and Gen Chen
- Subjects
Materials science ,Diffusion ,Oxygen evolution ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,0104 chemical sciences ,Catalysis ,Gibbs free energy ,Biomaterials ,symbols.namesake ,Adsorption ,Chemical engineering ,symbols ,General Materials Science ,Particle size ,0210 nano-technology ,Biotechnology ,Nanosheet - Abstract
Layered serpentine Ni3 Ge2 O5 (OH)4 is compositionally active and structurally favorable for adsorption and diffusion of reactants in oxygen evolution reactions (OER). However, one of the major problems for these materials is limited active sites and low efficiency for OER. In this regard, a new catalyst consisting of layered serpentine Ni3 Ge2 O5 (OH)4 nanosheets is introduced via a controlled one-step synthetic process where the morphology, size, and layers are well tailored. The theoretical calculations indicate that decreased layers and increased exposure of (100) facets in serpentine Ni3 Ge2 O5 (OH)4 lead to much lower Gibbs free energy in adsorption of reactive intermediates. Experimentally, it is found that the reduction in number of layers with minimized particle size exhibits plenty of highly surface-active sites of (100) facets and demonstrates a much enhanced performance in OER than the corresponding multilayered nanosheets. Such a strategy of tailoring active sites of serpentine Ni3 Ge2 O5 (OH)4 nanosheets offers an effective method to design highly efficient electrocatalysts.
- Published
- 2018
- Full Text
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