RSC Advances
·
2021
·Vol. 11
·期 49
·30961-30970
·
IF 3.361
Yongzhen Qiao,Xiu Wang,Hongqi Dai
The starch used to enhance the paper surface dissolves in water during the production process and forms pollutants that accumulate in water when old corrugated cardboard (OCC) is returned to a paper mill for pulping and reuse. At present, anaerobic fermentation is widely used in the paper industry to treat starch-containing wastewater, producing biogas energy, or oxidative decomposition, which is a huge waste of valuable starch resources. Phosphomolybdic acid (PMo12) is a highly selective catalyst for the oxidation of carbohydrates; therefore, PMo12 can be envisaged as a suitable catalyst to convert waste starch into glycolic acid, an important high added-value chemical. In this paper, the catalytic oxidation technology of PMo12 was explored to produce glycolic acid from starch contained in OCC papermaking wastewater, and the kinetics and influencing factors of the catalytic oxidation reaction were studied. The results indicated that the PMo12-catalyzed oxidation of starch followed a first-order reaction; the reaction rate constant increased with increasing the temperature, the apparent activation energy of starch to monosaccharide was 104.7 kJ mol−1, the apparent activation energies of starch and monosaccharide to humins were 126.5 and 140.5 kJ mol−1, and the apparent activation energy of monosaccharide to glycolic acid was 117.2 kJ mol−1. The yields of monosaccharide and glycolic acid were 80.7 wt% and 12.9 wt%, respectively, and the utilization of starch resources was about 90.0 wt% under the following reaction conditions: temperature, 145 °C; reaction time, 120 min; pH, 2. Therefore, the feasibility of the PMo12-catalyzed oxidation of starch to produce high value-added glycolic acid is demonstrated, which has theoretical guiding significance and potential application value for the clean production and resource utilization of waste starch in the OCC papermaking process.
研究领域:
环境科学
·
化学工程
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DOI
PubMed
高影响因子
Catalysts
·
2023
·Vol. 13
·期 10
·1327
·
IF 3.9
Di Wang,Jiangang Lv
Methyl glycolate was synthesized as a precursor to ethylene glycol from the acid-catalyzed carbonylation of formaldehyde, followed by esterification with methanol. Homogeneous acids and different solid acids (e.g., resins and zeolites) were used as catalysts, and the effect of the solvent was examined. Afterward, a carboxylic acid protection strategy was proposed. With sulfolane and acetic acid as the mixed solvent, the solubility of CO increases, and the reaction rate can be accelerated. The rapid reaction between acetic acid and glycolic acid inhibits glycolic acid polymerization and pulls the reaction balance to promote the carbonylation reaction rate. Under the optimal solvent system (a molar ratio of acetic acid to sulfolane of 1:5) and the appropriate reaction conditions, the selectivity of the target product is higher than 85%. Solid acid catalysts with a −SO3H or −CF2SO3H functional group are supposed to be efficient in the carbonylation of formaldehyde, based on which a supported Nafion catalyst with a high surface area and total acid content was designed and synthesized. The novel supported Nafion catalyst presents a high total acid content and high Brönsted–Lewis acid ratio due to the characteristics of modified zeolite and, thus, leads to the high reactivity and very low selectivity of the by-product. A possible reaction mechanism is proposed to explain the product’s distribution by ascribing the formation of different products to different types of acid sites.Keywords:carbonylation;formaldehyde;methyl glycolate;ethylene glycol;acid catalyst
研究领域:
化学合成
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2019
·Vol. 19
·期 12
·7635-7644
·
IF 1.093
Rong Qianyun,Zhang Dapeng,Li Ying,Zha Zhenxing,Geng Xinxiang,Cui Shihai,Yang Jing
A novel Bi2MoO6/Bi2Ti2O7 heterojunction photocatalyst was firstly prepared by a simple solvothermal route. The as-synthesized photocatalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray
diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence spectra. The effect of the material ratio, solution pH, and the salinity on glycolic acid degradation were discussed. The Bi2MoO6/Bi2Ti2O7
(2:1) nanocomposite exhibits highest photocatalytic performance and chemical stability. The glycolic acid degradation efficiency can reach 99.9% at pH 4 after 150 min irradiation under visible light. The enhanced photocatalytic activity can be ascribed to the heterojunction interface in the
composite, which is beneficial to the efficient charge carriers transfer. The degradation conforms to the pseudo-first-order kinetics. According to the oxidation species trapping experiments, the ·O2
−, h
+ and ·OH
are found to play important roles in the photocatalytic degradation and ·O2
− is the main active species. The possible photocatalytic mechanism was further discussed on account of valence band, conduction band positions and possible transition states.
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Zhihao Zhu,Guodong Kang,Ying Sun,Sha Yu,Meng Li,Jie Xu,Yiming Cao
The batch and continuous synthesis of glycolic acid via carbonylation of formaldehyde using high-temperature and high-pressure poly(tetrafluoroethylene) (PTFE) membrane contactor was demonstrated in this paper. The experiments in conventional stirred tank reactor were also conducted for comparison. The results showed that the yield of glycolic acid was significantly improved in membrane contactor system compared to the stirred tank reactor. At reaction temperature of 120 °C and reaction pressure of 5.0 MPa, the yield of glycolic acid was higher than 90% when the reaction time was 1 h, while it was only about 45% in the conventional stirred tank reactor. The enhancement of yield was due to the improvement of mass transfer or dispersion of CO in membrane contactor system, which could provide larger gas-liquid contact area and shorter mass transfer distance. The stability of PTFE hollow fibre membranes was also investigated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), liquid entry pressure (LEP), bubble point (BP) and contact angle (CA) measurements. The characterizations indicated that PTFE membranes exhibited good chemical and thermal stability in this reaction system. This study provided new idea and reference for the carbonylation of formaldehyde and similar gas-liquid reactions.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Zhihao Zhu,Ying Sun,Haijun Yu,Meng Li,Xingming Jie,Guodong Kang,Yiming Cao
Membrane contactor is regarded as a promising method for reaction and process intensification. The feasibility of formaldehyde carbonylation to synthesize glycolic acid using polytetrafluoroethylene (PTFE) membrane contactor has been proved in our previous study. In this paper, the effect of membrane microstructure on process performance was further investigated. Three porous PTFE hollow fibers with different pore sizes and one polydimethylsiloxane (PDMS)/PTFE composite membrane with dense layer were fabricated for comparison. The physical and chemical properties of four membranes, including chemical composition, morphology, contact angle, liquid entry pressure, thermodynamic analysis and gas permeability, were systemically characterized. Experiments of formaldehyde carbonylation under different reaction conditions were conducted. The results indicated that the yield of glycolic acid increased with decreasing pore size for porous membranes, which was due to the improvement of wetting behavior. The dense layer of PDMS in composite hollow fiber could effectively prevent the solvent from entering membrane pores, thus the membrane exhibited the best performance. At reaction temperature of 120 °C and operation pressure of 3.0 MPa, the yield of glycolic acid was always higher than 90% as the mass ratio of trioxane and phosphotungstic acid increased from 0.2:1 to 0.8:1. The highest turnover frequency was up to 26.37 mol⋅g −1 ⋅h −1 . This study provided a reference for the understanding and optimization of membrane contactors for the synthesis of glycolic acid using solvent with low surface tension.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Wenjuan Shen,Bingning Wang,Falong Jia,Zhihui Ai,Lizhi Zhang
In general, the final product of atrazine (ATR) degradation by reactive oxygen species is cyanuric acid bearing a stable s -triazine ring, which is not further oxidized under mild conditions. In this study, we demonstrate that the presence of Ni(II) can increase the aerobic ATR degradation rate of core–shell Fe@Fe 2 O 3 nanowires (CSFN) by 6 times and also achieve the cleavage of recalcitrant s -triazine ring. The cleavage of s -triazine ring in this novel system was confirmed by the measurements of formic acid and nitrite acid. On the basis of experimental results, a feasible mechanism was proposed to account for the promoted aerobic ATR degradation and the facile s -triazine ring cleavage as follows. First, Ni(II) adsorbed on the surface of CSFN was reduced to nickel metal, which favored the generation of active hydrogen (•H). The in-situ generated •H then reduced ATR to 4-ethylamino-6-isopropylamino-1,3,5-triazine intermediate of easy ring opening property, rather than the recalcitrant cyanuric acid. Finally, this ATR degradation pathway change promoted the aerobic ATR degradation and benefited the s -triazine ring cleavage. This study clarifies the importance of degradation pathway on the ring-opening of organic pollutants, and also provides a mild method to remove s -triazine herbicides with molecular oxygen and zero-valent iron.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Almas Anwar,Tao Zhao,Sidra Ghaffar,Kai Nie,Wenying Xia,Lingyu Wang,Zhihao Cao,Xiaoli Yang,Chengfeng Zhou,Yuanming Zhang,Guangting Han,Wei Jiang,Haoxi Ben
Hemp, a sustainable crop, offers superior material properties suitable for diverse applications. This study aims to produce hemp fibre using a green and sustainable pretreatment method, thus exploring a novel microwave-assisted pretreatment method using a γ-valerolactone (GVL) and glycolic acid (GA) solution system, referred to as the GVL/GA pretreatment method. By optimising solid loading and reaction time, we significantly reduced water usage (50 %) and energy consumption (61.5 %) while maintaining fibre quality. The pretreatment method effectively removed lignin (88.7 %) and hemicellulose (39.3 %) without damaging the cellulose structure. The pretreated samples demonstrated a 45.7 % increase in glucose yield. Additionally, the characterisation of pretreated fibres revealed impressive fineness (4.4 dtex) and tenacity (4.0 cN/dtex), and the crystal structure remained intact with increased crystallinity (86 %). The HSQC NMR analysis unveiled that lignin undergoes structural modifications, enabling efficient lignin removal. GVL/GA pretreatment promotes green chemistry by minimising environmental impact and waste, using renewable resources. It provides a sustainable alternative to traditional methods, contributing to a greener industry.
研究领域:
材料科学
·
环境科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 53
·30163-30170
·
IF 2.936
Lei Feng,Gang Li,Yueer Yan,Wenrong Hou,Yahong Zhang,Yi Tang
The present work deals with the one-pot conversion of C6 sugars to methyl glycerate and glycolate via a cascade of retro-aldol condensation and oxidation processes catalyzed by using MoO3 as the Lewis acid catalyst and Au/TiO2 as the oxidation catalyst in methanol. Methyl glycerate (MGLY) is the product of C6 ketose (fructose), while methyl glycolate (MG) is produced from C6 aldose (mannose, glucose). It is found that a good one-pot match between two reactive processes is the key to the production of MGLY and MG with high yield (27.6% MGLY and 39.2% MG). A separated retro-aldol condensation and oxidation process greatly decreases their yields, and even no MGLY can be obtained in this separated process. We attribute this to high instability of glyceraldehyde/glycolaldehyde and their different reaction pathways which mainly depend on whether acetalization of retro-aldol products (glyceraldehyde and glycolaldehyde) occurs with methanol or not. This result opens a new prospect on the accumulation of C3 products other than lactate from biomass-derived carbohydrates.
研究领域:
化学工程
·
催化
·
生物化学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-10
·
IF 15.7
Wang Shixun,Wang Shengnan,Wei Zhiquan,Wang Yiqiao,Zhang Dechao,Chen Ze,Zhi Chunyi
Zinc-ion batteries have demonstrated promising potential for future energy storage, whereas drawbacks, including dendrite growth, hydrogen evolution reaction, and localized deposition, heavily hinder their development for practical applications. Herein, unlike elaborated structural design and electrolyte excogitation, we introduce an effective parts-per-million (ppm)-scale electrolyte additive, phosphonoglycolic acid (PPGA), to overcome the intrinsic issues of zinc negative electrode in mild acidic aqueous electrolytes. Profiting from absorbed PPGA on zinc surface and its beneficial interaction with hydrogen bonds of adjacent water molecules, stable symmetric stripping/plating of zinc in aqueous ZnSO 4 electrolyte at around 25 o C was achieved, procuring 362 and 350 days of operation at 1 mA cm -2 , 1 mAh cm -2 and 10 mA cm -2 , 1 mAh cm -2 , respectively. As a proof-of-concept, an Ah-level Zn||Zn 0.25 V 2 O 5 ·nH 2 O pouch cell examined the validity of PPGA and sustained 250 cycles at 0.2 A g -1 and around 25 o C without capacity loss. The Zn||Br 2 redox flow battery demonstrated an operation of over 800 h at 40 mA cm -2 , 20 mAh cm -2 with an average coulombic efficiency of 98%, which is attributed to restrained dendrite growth and side effects. This work is believed to open up new ways forward for knowledge of electrolyte additive engineering.
研究领域:
能源存储
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2022
·
IF 4.432
Jian Wang,Weiping Chen,Libin Bai,Yuelan Tian,Xinwu Ba
Poly(ethylene succinate) (PES) with high chain regularity was synthesized by adding oxalic acid in the melt poly-condensation system. The molar ratios of diethylene glycol succinate (DEGS) units in the polymer chains were diminished from 3.8% to 0.6% when 17 mol% oxalic acid was added. Oxalic acid underwent esterification with ethylene glycol and decarboxylation , producing ethylene glycol monoformate and formate end-capped PES oligomers . The formate endcapping supressed the etherification side reactions. Ethylene glycol formate with a lower boiling point was more easily released by-production than ethylene glycol during the transesterification stage, resulting in a faster transesterification rate. Meanwhile, the molecular weights significantly increased. The high chain regularity endowed the PES with higher melting temperatures of 105 °C and remarkably increased crystallization rates. The mechanical properties , including tensile strength at break, were simultaneously improved for a high-molecular-weight PES sample ( M w = 100 kg/mol).
研究领域:
聚合物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Hongbin Xia,Yuxin Wang,Rui Xia,Xinyang Xiong,Guangwen Xu,Jinggang Zhao,Jun Zhou,Lei Shi
An acetate-functionalized heterogeneous catalyst, N + -(Ac), was successfully synthesized via directed substitution of an inert site in quaternary ammonium resin by a weak-base active center and applied to the transesterification of dimethyl oxalate (DMO) with ethanol to prepare diethyl oxalate (DEO). When the optimal N + -(Ac) catalyst catalyzed the DMO transesterification with ethanol for 2 h, the DMO conversion, DEO yield, and corresponding turnover frequency (TOF) reached 93.4%, 49.7%, and 13.04 h −1 , respectively. Additionally, the synthesized N + -(Ac) exhibited catalytic universality for DMO transesterification with different alcohols, and the catalytic efficiency decreased with increasing difficulty of cleaving the hydrogen–oxygen bond from C 2 to C 4 and steric hindrance of isomeric alcohols. The pretreatment experiments of catalyst with different water content and raw materials were designed and the resin matrix, fresh catalyst, deactivated catalyst and regenerated sample were systematically analyzed using various characterization techniques to investigate the catalytic deactivation mechanism of the transesterification reaction between DMO and ethanol to synthesize DEO. The results showed that DMO played a key role in catalyst deactivation and the catalyst was deactivated upon replacement of the active sites by monomethyl oxalate anions from hydrolysis side reaction of DMO. Finally, an efficient raw material regeneration strategy for the catalyst was proposed. Herein, new theoretical support is introduced for the structural evolution of weak-base catalysts and will aid in developing heterogeneous catalysts for oxalate transesterification.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULAR MEDICINE
·
2022
·Vol. 28
·期 1
·1-20
·
IF 6.376
Ming Shaoxiong,Tian Jia,Ma Ke,Pei Chengbin,Li Ling,Wang Zeyu,Fang Ziyu,Liu Min,Dong Hao,Li Weijian,Zeng Jianwen,Peng Yonghan,Gao Xiaofeng
Background Kidney stones are composed of approximately 70–80% calcium oxalate. However, the exact mechanism of formation of calcium oxalate kidney stones remains unclear. In this study, we investigated the roles of endoplasmic reticulum stress (ERS), reactive oxygen species (ROS), and the NF-κB signalling pathway in the pathogenesis of oxalate-induced renal tubular epithelial cell injury and its possible molecular mechanisms. Methods We established a model to evaluate the formation of kidney stones by intraperitoneal injection of glyoxylic acid solution into mice and assessed cell morphology, apoptosis, and the expression levels of ERS, ROS, and NF-κB signalling pathway-related proteins in mouse renal tissues. Next, we treated HK-2 cells with potassium oxalate to construct a renal tubular epithelial cell injury model. We detected the changes in autophagy, apoptosis, and mitochondrial membrane potential and investigated the ultrastructure of the cells by transmission electron microscopy. Western blotting revealed the expression levels of apoptosis and autophagy proteins; mitochondrial structural and functional proteins; and ERS, ROS, and NF-κB (p65) proteins. Lastly, we studied the downregulation of NF-κB activity in HK-2 cells by lentivirus interference and confirmed the interaction between the NF-κB signalling and ERS/ROS pathways. Results We observed swelling of renal tissues, increased apoptosis of renal tubular epithelial cells, and activation of the ERS, ROS, and NF-κB signalling pathways in the oxalate group. We found that oxalate induced autophagy, apoptosis, and mitochondrial damage in HK-2 cells and activated the ERS/ROS/NF-κB pathways. Interestingly, when the NF-κB signalling pathway was inhibited, the ERS/ROS pathway was also inhibited. Conclusion Oxalate induces HK-2 cell injury through the interaction between the NF-κB signalling and ERS/ROS pathways.
研究领域:
肾病学
·
细胞生物学
·
分子生物学
·
病理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）