BIORESOURCE TECHNOLOGY
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2024
·
IF 9.7
Haojie Yang,Xue Li,Shasha Liu,Guiying Lin,Xin Guo,Xin Wang,Kuan Ding,Yong Huang,Shu Zhang
Due to the complexity of biomass structures, the conversion of raw biomass into value-added chemicals is challenging and often requires efficient pretreatment of the biomass. In this paper, a simple and green pre-oxidation method, which was conducted under the conditions of 2 wt% H 2 O 2 , 80 min, and 150 °C, was reported to significantly increase the production of levoglucosan (LG) from biomass pyrolysis. The result showed that the LG yield significantly increased from 2.3 wt% (without pre-oxidation) to 23.1 wt% when pine wood was employed as a sample for pyrolysis at 400 °C, resulting from the removal of hemicellulose fraction and the in-situ acid catalysis of lignin carboxyl groups formed during the pre-oxidation. When the conditions for pre-oxidation became harsher than the above, the LG yield reduced because the decomposition of cellulose fraction in biomass. The study supplies an effective method for utilization of biomass as chemicals.
研究领域:
化学工程
·
生物质能
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产品关联
DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Guangchuan Tang,Xin Huang,Hui Qin,Chuan Ma,Yunlin Shao,Zhongqing Yang,Changlei Qin,Jingyu Ran
Levoglucosan (LGA), as the main primary anhydrosugar of cellulose pyrolysis , is of great significance for future value-added chemicals production. In this study, effective conversion of LGA to 5-hydroxymethylfurfural (HMF) was investigated in a NaCl–H 2 O/acetone biphasic system over sulfonated resin and AlCl 3 . The results show that the biphasic system could efficiently inhibit the overreaction of HMF compared with pure water, leading to a significant enhancement of HMF production. HMF was obtained with the highest yield of 68.5 % at 96.5 % of LGA conversion at the optimized conditions. The use of cellobiose as substrate produced 61 % of HMF while LGA-rich bio-oil led to a sharp decease of HMF yield to 33 %. Through the respective experiments using LGA, glucose and fructose as the substrates, the reaction network was constructed for kinetic analysis, and satisfactory fitting results are observed in agreement with the experimental results, providing the best conditions for producing glucose and HMF, respectively. In addition, the mechanism of LGA conversion to HMF was calculated by DFT, which needs to overcome the highest free energy barrier of 121 kJ/mol.
研究领域:
化学工程
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生物质能
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催化反应
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Xin Huang,Guangchuan Tang,Lei Tang,Chuan Ma,Yunlin Shao,Jingyu Ran
Bio-based platform chemicals are of great significance to future green fine and commodity chemicals. This study reports the performances and mechanisms of solvothermal dehydration of levoglucosan (LGA), the main precursor from noncatalytic pyrolysis of cellulose with a yield up to 80 wt %, to levoglucosenone (LGO) using cesium heteropolyacid salts at the catalyst in DMSO solvent. Catalyst characterizations revealed that cesium was well doped in the cubic of heteropolyacids, and the cesium doping ratio substantially influenced the catalytic performances toward LGO. LGO yield first increased and then decreased with the increase of cesium doping ratios, which is consistent with the change trends of pore structures and Brønsted/Lewis acid site ratios of the cesium heteropolyacid salts. LGO was obtained with the maximum yield at 41.2% over Cs2H2SiW12O40 compared to 39.2% over Cs2.5H0.5PW12O40. The catalyst can be regenerated by calcination without losing its catalytic performances. In addition, density functional theory calculation was used to reveal the mechanism for LGO formation, and the rate-determining step was the first step of the dehydration reaction with the energy barrier of 166 kJ/mol.
研究领域:
化学工程
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可再生资源与环境科学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Chi Yang,Chunyan Zhang,Xiaosan Luo,Xiaoyan Liu,Fang Cao,Yan-lin Zhang
So far, studies on the conversion of stereochemistry under photo-Fenton conditions and their atmospheric implication are still rare. Here, we found that the biomass burning marker, the chiral compound levoglucosan (L), undergoes oxidative degradation under photo-Fenton conditions and can be isomerized into mannosan (M) and galactosan (G) simultaneously. Among the formic acid, acetic acid, and oxalic acid in the degradation products of levoglucosan, it was found that the yield of formation of formic acid in the photo-Fenton pathway can be as high as 86%. It is worth noting that both levoglucosan and its isomers are present in the atmosphere and their concentrations are strongly correlated. At the same time, the range of their concentration ratios, L/(G + M), measured in the photo-Fenton experiments in the laboratory was found to agree well with that measured in atmospheric PM2.5 samples. However, the sources of L, G, and M in the atmosphere are complex, and the photo-Fenton reaction may be an essential pathway for the distribution of L, G, and M in the atmosphere.
研究领域:
环境科学
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大气化学
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DOI
高影响因子
Catalysis Science & Technology
·
2020
·Vol. 10
·期 9
·2986-2993
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IF 5.721
Wenda Hu,Zixin Chi,Yan Wan,Shuai Wang,Jingdong Lin,Shaolong Wan,Yong Wang
This work presents a novel method to selectively convert levoglucosan to lactic acid (LA) via initially adding LA as the Brønsted acid together with modified Sn-β as the Lewis acid. Sn-β catalysts exchanged with various cations significantly enhance the yield of LA, following the order Sn-β < Sn-β–Na < Sn-β–K < Sn-β–Mg, Sn-β–Ca. The role of exchanged alkali ions stems from removing the remaining Brønsted acid sites in the zeolite and tuning the framework oxygen with more Lewis base sites. The exchange with alkaline earth cations such as Ca2+ and Mg2+ appears to be more effective in promoting the retro-aldol condensation due to the synergetic effect of their stronger Lewis acid that can stabilize the oxygen atom of deprotonated alkoxides during the reaction. The LA yield from levoglucosan can reach up to 66% on Sn-β–Ca under the optimized conditions. We also demonstrated that such a synergetic effect of alkaline-earth ion exchanged Sn-β shows great universality toward enhanced retro-aldol condensation, which can significantly promote the yield of methyl lactate over glucose conversion in methanol solvent.
研究领域:
催化化学
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生物质转化
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绿色化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 10
·7030-7036
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IF 3.9
Xiunan Yao,Ninglian Wang,Xingwang Zheng,Quanlian Li,Ewerton Santos,Linda Maharjan,Junjie Wang,Zhihui Guo,Jiahua Guo,Huan Zhang,Kui Zheng,Jingquan Wu,Yao Li
The sensitive determination of levoglucosan in aqueous samples has great significance for the study of biomass burning. Although some sensitive high-performance liquid chromatography/mass spectrometry (HPLC/MS) detection methods have been developed for levoglucosan, there are still plenty of shortcomings, such as complicated sample pre-treatment procedures, large-amount sample requirements, and poor reproducibility. Herein, a new method for the determination of levoglucosan in the aqueous sample was developed using ultra-performance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS/MS). In this method, we firstly found that compared with H+, Na+ could effectively enhance the ionization efficiency of levoglucosan, even though the content of H+ is higher in the environment. Moreover, the precursor ion m/z 185.1 [M + Na]+ could be used as a quantitative ion to sensitively detect levoglucosan in aqueous samples. Only 2 μL of un-pretreated sample is required for one injection in this method, and great linearity was obtained (R2 = 0.9992) using the external standard method when the concentration of levoglucosan was 0.5–50 ng mL−1. The limit of detection (LOD) and quantification (LOQ) were 0.1 ng mL−1 (0.2 pg absolute mass injected) and 0.3 ng mL−1, respectively. Acceptable repeatability, reproducibility, and recovery were achieved. This method has the advantages of high sensitivity, good stability, good reproducibility, and simple operation, which could be widely used for the detection of different concentrations of levoglucosan in various water samples, especially for the detection of samples with low content such as ice core or snow samples.
研究领域:
分析化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Sustainable Energy & Fuels
·
2018
·Vol. 2
·期 8
·1855-1862
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IF 0
Jiajin Liang,Jiao Chen,Shubin Wu,Chao Liu,Ming Lei
Comprehensive understanding of cellulose pyrolysis is critical to valuable chemical and liquid fuel generation in biomass-based biorefining processes. Herein, a specific tubular reactor was designed to observe the cellulose appearance alteration corresponding to the chemical structure evolution in various pyrolysis stages. The appearance of cellulose changed from white powder to light brown powder below 300 °C as its crystal lattice thermal expansion and the degree of crystallinity decrease. Cellulose began to depolymerize at 300 °C accompanied with the dehydration of pinacol and primary product levoglucosan generation. 325–350 °C was the critical pyrolysis stage for cellulose. The intermediate state was formed accompanied with a series of thermochemical reactions. All the typical signals from FTIR, 13C CP/MAS NMR disappeared when the temperature was up to 350 °C. The percentages of C, H, and O conversion to the volatile products were up to 35%, 55% and 60%, respectively, along with β-1,4-glycosidic bond cleavage, decarboxylation, and decarbonylation reactions. Meanwhile, CO2, CO, and CH4 were measured using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer (TG-FTIR) in the slow pyrolysis process. The increasing C/H and C/O ratios in the carbonation stage enhanced the aromaticity of biochar. Furthermore, electron paramagnetic resonance (EPR) analysis indicated that it tended to form carbon-centered radicals.
研究领域:
生物质能
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化学工程
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材料科学
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产品关联
DOI
JOURNAL OF APPLIED CRYSTALLOGRAPHY
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2023
·Vol. 56
·期 2
·468-476
·
IF 6.1
Lu G.,Zhou H.,Wei L.,Zhao X.,Li Z.,Huang Y.
Levoglucosan is a typical orientationally disordered crystalline material (the molecules are long-range positionally ordered but orientationally disordered). At present, experimental research on its glass transition is mainly focused on polycrystals, while the study of the corresponding single crystals is rarely reported. Centimetre-size (maximum dimensions of 2.1 × 0.9 × 0.4 cm) levoglucosan single crystals of high quality were grown by the solution method, laying a necessary foundation for experimental measurements of the glass transition mechanism in the material.
✓ 已验证
DOI
高影响因子
Environmental Chemistry Letters
·
2024
·
IF 15
Zhang Shuai,Ma Jingjing,Liu Xiangjun,Ma Yayun,Wang Junqi
Pyrolysis of modern biomass is a sustainable technique to produce chemicals, yet efficient and selective conversion remains challenging. We studied biomass pyrolysis catalyzed by graphene oxide for the production of levoglucosan, a chemical with potential applications in biodegradable plastics and surfactants. We tested model compounds containing 40–100 wt% cellulose, poplar biomass, and we modelled the role of graphene oxide by calculations using the density functional theory. Results for model compounds show that levoglucosan production is higher for compounds containing less than 50% cellulose. By contrast, levoglucosan yield are reduced for model compounds having more than 60 wt% cellulose, because graphene oxide induced the breakdown of levoglucosan. Experiments show that pyrolysis of poplar biomass with 5 wt% graphene oxide increased about three times the yield of levoglucosan, compared to non-catalyzed pyrolysis. Enhanced levoglucosan formation is explained by the formation of a six-membered ring intermediate.
研究领域:
能源科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Guangchuan Tang,Xin Huang,Anbang Xu,Zhongqing Yang,Changlei Qin,Jingyu Ran
Pyrolysis of cellulose produces substantial anhydrosugars, particularly levoglucosan (LGA), as the main product. In this study, liquid-phase continuous conversion of LGA was carried out over SO 3 H functionalized resin for the production of levogluosenone (LGO), which is a bio-renewable platform for fine and commodity chemicals. Factors including solvent, reaction temperature, catalyst dosage, initial LGA concentration and total flow rate were investigated on the influence of LGO yield, which was obtained with the highest yield of 38.4 % at 94.8 % LGA conversion at the optimized conditions. In addition, a stable catalytic performance without losing LGO yield was observed for 10 h long test. The use of glucose as substrate led to a decrease of LGO yield to 33.5 %, nevertheless, the use of bio-oil, derived from cellulose pyrolysis, as the substrate promoted LGO yield to 55.4 % due to the presence of other anhydrosugars. Density functional density calculations revealed that the free energy barrier was significantly decreased to 168 kJ/mol with the SO 3 H functionalized resin compared to that of 258 kJ/mol without catalyst.
研究领域:
生物化学
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可再生资源与环境工程
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产品关联
DOI
高影响因子
CELLULOSE
·
2020
·Vol. 27
·期 17
·9825-9838
·
IF 4.21
Cao Qi,Ye Tian,Li Wenhui,Chen Jiao,Lu Yanyu,Gan Haifeng,Wu Hongli,Cao Fei,Wei Ping,Ouyang Pingkai
The dehydration of cellulose in polar aprotic solvents produces high-value anhydro-sugars, opening up a new avenue for the utilization of cellulose. However, there are still some problems that need to be solved. Herein, we selected some carbohydrates (e.g. cellulose, starch, cellobiose, maltose, methyl-β-D-glucopyranoside and methyl-α-D-glucopyranoside) to examine the influence of different glycosidic bonds and substituents on the preparation of levoglucosan (LGA). The results of LGA yields, reaction rate constants and activation energies from different saccharides show that β-glycosidic bond is more vulnerable to break, forming LGA more easily. The activation energies of the latter 4 carbohydrates are 89.9, 104.2, 93.3, 113.6 kJ/mol, respectively. The strength of acid affects the dehydration process of cellulose greatly. These acids whose p K a values are between − 3 and − 2, including p -toluenesulfonic acid, methanesulfonic acid, and sulfuric acid, can achieve the best yields of LGA and levoglucosenone (LGO). Accordingly, those acids with higher p K a value have no catalytic activity, whereas the rate of cellulose degradation using lower p K a valued acids as catalyst is too fast to be efficiently monitored and carbonization is severe. The side reaction of cellulose hydrolysis and the formation of byproducts including 5-hydroxymethylfurfural (HMF) and furfural (FF) could be suppressed effectively through the addition of phosphorus pentoxide as water absorbent into the reaction system. The molar concentration ratio of LGO and (HMF + FF + Glucose) reached 12.04, which is 105% higher than those without water absorbent. This ratio can reach 21.38 in LGA dehydration into LGO process when phosphorus pentoxide was added.
研究领域:
生物化学
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有机化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 95
·期 3
·798-805
·
IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
研究领域:
化学工程
·
生物质能
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）