CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Ce Gao,LingPing Xiao,Jinghui Zhou,Haisong Wang,Shangru Zhai,Qingda An
A new type of nanosilver immobilized catalyst based on glycine modified lignin hydrogels with excellent catalytic performance towards p -nitrophenol reduction have been prepared. Glycine was used to provide amino and carboxy groups for complexing silver ions, simultaneously which was also beneficial for in-situ reduction and suppression of silver nanoparticles. As-prepared composites were characterized by X-ray diffraction, scanning electron microscope with EDS, high-resolution transmission electron microscope, X-ray photoelectron spectroscopy, Fourier Transform Infrared Spectrometer and Thermal Gravimetric Analyzer. The developed network with enriched anchoring sites could provide the stability during the catalytic process and enough traction to disperse and stabilize the silver nanoparticles. Batch experiments of 4-NP hydrogenation were carried out to correlate the catalytic performance. The concentration of 4-NP of 5 mmol/L could be finished with only 101 s and the rate of k was 0.0151 s −1 . Moreover, fixed-bed experiments were creatively applied for the tests and the catalyst can maintain high efficiency about 300 min with the flowing rate of 3 mL/min. After being reused ten cycles, the catalyst retained the conversion rate beyond 98%; and the structure has no obvious deterioration and the leaching of nanosilver was neglectful, which could be attributed to the crucial role of introduced glycine component.
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2020
·
IF 7.635
Yiding Cao,Zhenzhen Liu,Bixia Zheng,Rongxian Ou,Qi Fan,Liping Li,Chuigen Guo,Tao Liu,Qingwen Wang
Sustainable thermosetting polyurethane (PU) anticorrosive coatings based on renewable biomass resources with long-lasting corrosion protection is highly desired. Herein, thermosetting lignin-based polyurethanes (LPU) coatings with superior corrosion resistance and high content of lignin were prepared by polymerization of lignin-based polyol (OH-EL) with hexamethylene diisocyanate (HDI) in absence of catalysts. In order to increase the reactivity and solubility of OH-EL when reacting with isocyanates, the phenolic hydroxyls of enzymatic hydrolysis lignin were selectively converted to primary aliphatic hydroxyls by sequential alkylation and thiol-ene reaction. Due to the well dispersion and crosslinking reactivity of OH-EL in the polyurethane networks, the resulting LPUs presented high thermal stability and excellent mechanical properties . Remarkably, LPU-3 with the content of OH-EL of 54.8 wt%, exhibited high T g of 112 °C, high char residue percentage of 26.3% at 600 °C, high tensile strength up to 81.6 MPa and tensile modulus of 1.4 GPa. Moreover, the LPU-3 coating on carbon steel substrate exhibited low corrosion current density I corr of 7.58 × 10 −11 A cm −2 , positive corrosion voltage E corr of 118 mV, and high impedance modulus |Z| 0.01Hz of 8.3 × 10 10 Ω cm 2 after immersing in 3.5 wt% NaCl solution for 0.5 h, and the |Z| 0.01Hz remained at 3.9 × 10 10 Ω cm 2 after 40 days immersion, displaying superior corrosion resistance than other reported bio-based polymer coatings . These results demonstrate that the synthesis of highly reactive lignin-based polyols based on thiol-ene chemistry is an effective and facile strategy, which is vital for the development of high-performance bio-based polyurethane anticorrosive coatings.
✓ 已验证
产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Zhongzhi Yang,Junfeng Feng,Haowen Cheng,Yongxiang Liu,Jianchun Jiang
This work exploits a one-pot method for directional depolymerizing organosolv lignin into high added-value phenolic monomers with synergistic reaction system consisted of methanol-dimethoxymethane binary solvents and acid catalyst. The influence of solvent composition and reaction parameters such as different catalyst, binary solvents ratio, time, and temperature on the conversion of lignin and yield of products were investigated carefully, the optimum yield of liquid products and phenolic monomers were achieved at 67.39% and 27.67% at 200 °C kept for 60 min with low amount of acid catalyst. The plausible mechanism on the depolymerization of lignin was proposed in view of product distributions. Moreover, the combination of co-solvents and acidic catalyst was also suitable for converting different types of lignin into phenolic monomers, and the recyclability of joint reaction system was satisfactory. These results can provide promising prospects on developing an effective method for achieving high added-value phenolic compounds from lignin.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2020
·
IF 4.982
Zi Zeng,Jiaoyang Xie,Yue Guo,Ruiheng Rao,Bo Chen,Lihua Cheng,Ying Xie,Xinping Ouyang
Highly dispersed Fe Pd bimetallic catalyst supported on HZSM-5 (Fe-Pd/HZSM-5) was prepared by impregnation method for the hydrogenolysis of lignin. The correlation between the textural properties of the catalyst and its catalytic activity to lignin hydrogenolysis were investigated. The presence of Fe facilitates the dispersion of Pd, and the particle size decreases from 6.1 nm for 3.0 wt% Pd/HZSM-5 (Pd-3.0) to 2.5 nm for 9.0 wt% Fe-1.0 wt% Pd/HZSM-5 (FP-1.0). Fe is mainly existed in the oxidized state which means that electrons in Pd tend to transfer to FeO x , facilitating the activation of H 2 to form active H atoms. Due to the geometric and electronic synergistic effects , FP-1.0 bimetallic catalyst exhibits a good catalytic activity to lignin hydrogenolysis, contributing to as higher as 98.17% of lignin conversion and 27.92% of aromatic monomers yield under the optimal reaction conditions of 1 MPa H 2 at 320 o C for 120 min in ethanol-water solvent. FP-1.0 bimetallic catalyst with low cost and highly catalytic activity may be a potentially useful catalyst for selective hydrogenolysis of lignin.
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Xiao Zhou,Xian-Yong Wei,Yu-Miao Ma,Zhi-Min Zong
An active bifunctional nickel-based catalyst was prepared by decomposing Ni(CO) 4 to dispersive metallic Ni on Hβ zeolite and successfully applied in the catalytic hydroconversion (CHC) of an alkali lignin (AL). Detailed elemental composition, functional groups, and molecular compositions of the soluble portions (SPs) from non-catalytic hydroconversion (SP NCHC ) and CHC (SP CHC ) were characterized with an elemental analyzer, a Fourier transform infrared spectrometer, and a gas chromatograph/mass spectrometer (GC/MS). As a result, alkoxalkanes, phenol, cresol, veratrols, alkyl-substituted 1,4-dimethoxyphenols, 2,5-dimethylfuran, 3-hydroxyneopentanal, 4-methylpent-3-en-2-one, 4-methoxy-4-methylpentan-2-one, 1-(2,4-dihydroxy-3-tolyl)propan-1-one, and 2,5-dimethylhex-4-enoic acid only appear in SP CHC , and yields of multiple alkyl-substituted phenols, p -alkylanisoles, diols, non-substituted and alkyl-substituted methoxyphenols, and substituted phenylethanones in SP CHC are significantly higher than those in SP NCHC . The mechanism for catalytically hydrocracking >CH-O- bridged bonds over Ni/Hβ is proposed using benzyloxybenzene (BOB) and phenethoxybenzene as AL-related model compounds. Ni/Hβ proved to be stable after 3 cycles with relatively small loss in catalytic activity for catalyzing the hydrocracking of >CH-O- bonds in BOB.
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 71
·43599-43606
·
IF 3.119
Xiaomeng Dou,Wenzhi Li,Chaofeng Zhu,Xiao Jiang,Hou-min Chang,Hasan Jameel
Efficient cleavage of aryl–ether linkages is a key strategy for generating aromatic chemicals and fuels from lignin. Currently, a popular method to depolymerize native/technical lignin employs a combination of Lewis acid and hydrogenation metal. However, a clear mechanistic understanding of the process is lacking. Thus, a more thorough understanding of the mechanism of lignin depolymerization in this system is essential. Herein, we propose a detailed mechanistic study conducted with lignin model compounds (LMC) via a synergistic Co–Zn/Off-Al H-beta catalyst that mirrors the hydrogenolysis process of lignin. The results suggest that the main reaction paths for the phenolic dimers exhibiting α-O-4 and β-O-4 ether linkages are the cleavage of aryl–ether linkages. Particularly, the conversion was readily completed using a Co–Zn/Off-Al H-beta catalyst, but 40% of α-O-4 was converted and β-O-4 did not react in the absence of a catalyst under the same conditions. In addition, it was found that the presence of hydroxyl groups on the side chain, commonly found in native lignin, greatly promotes the cleavage of aryl–ether linkages activated by Zn Lewis acid, which was attributed to the adsorption between Zn and the hydroxyl group. Followed by the cobalt catalyzed hydrogenation reaction, the phenolic dimers are degraded into monomers that maintain aromaticity.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Reaction Chemistry & Engineering
·
2021
·Vol. 6
·期 3
·559-571
·
IF 4.239
Changzhou Chen,Dichao Wu,Peng Liu,Haihong Xia,Minghao Zhou,Xinglong Hou,Jianchun Jiang
The noble-metal catalytic cleavage of ether bonds in lignin to obtain aromatic chemicals has achieved great success, and the development of a low-cost efficient catalyst is crucial. Herein, NixLay/CNT was designed for the hydrogenolysis of benzyl phenyl ether (BPE), diphenyl ether (DPE) and 2-phenethyl phenyl ether (PPE) under a relatively mild condition. Owing to the synergistic effect of Ni with La, the Ni–La catalyst was especially active. Moreover, not only could the Ni–La catalyst fracture the C–O bond, but it could also transform aromatic rings to produce cycloalkanes. Physicochemical characterizations were carried out by means of XRD, TEM, H2-TPR, NH3-TPD, pyridine-IR and XPS analyses. Based on the optimal reaction condition (240 °C, 4 h, 2.0 MPa H2), various model compounds could also be effectively hydrotreated to produce corresponding products. A mechanistic study revealed that cyclohexanol and methylcyclohexane were major products for the transfer cleavage of BPE. Furthermore, it has been illustrated that aryl groups played a significant role in the hydrogenation of phenol from the competitive catalytic hydrogenation reaction of phenol. This study opened up the possibility of the valorization of lignin using a rare earth metal as the co-catalyst for the selective cleavage of lignin model compounds to value-added chemicals.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Lixia Li,Juanhua Kong,Huimin Zhang,Sijie Liu,Qiang Zeng,Yaqin Zhang,Hao Ma,Hongyan He,Jinxing Long,Xuehui Li
The catalytic depolymerization process for lignin to produce value added chemicals is often challenged by the limited mass transfer over heterogeneous catalysts, the complex aromatic biopolymer structures, and the high recalcitrance of C C bonds. Herein, a series of hierarchical MFI nanosheets (MFI-ns) supported metal oxide catalysts have been designed and used for the selectively oxidative cleavage of organosolv lignin. As expected, 81.6 % conversion of lignin can be achieved over 15Ce-5Cu/MFI-ns with 294.0 mg g −1 yield of volatile products, including 180.9 mg g −1 of diethyl maleate. Quantum chemistry calculation coupled with static adsorption measurements shows that the superior catalytic activities of these catalysts are ascribed to the favorable mass transport of lignin to the active sites by the unique layer structure, and the hierarchical pore sizes distribution, as well as the electronic effect between Cu and Ce components. In addition, the catalytic mechanism for the cleavage of C C bonds in β -O-4 model probes has been studied via the controlled oxidative degree of model compounds and the isotope-labeling experiments. Therefore, this work provides a new insight into the efficient utilization of lignin via the rational design of catalysts.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Bailiang Xue,Yang Yang,Rui Tang,Danwei Xue,Yongchang Sun,Xinping Li
Novel ternary deep eutectic solvents (DESs) were designed to efficiently dissolve the lignin for synthesizing the lignin-containing rigid polyurethane foam (LRPUF). These ternary DESs were constituted by choline chloride (ChCl), two hydrogen bond donors – glycerol (Gly) and polyethylene glycol (PEG-400). The maximum solubility of lignin in the sample DES-2 (ChCl:Gly:PEG-400 = 1:2:2) could up to 66.70 g/100 g solvent at 60 °C due to the hydrogen bonds are the main driving force, which was confirmed by the largest hydrogen bond basicity parameter β value and disappearance of crystalline peak. The main structure of the lignin did not change after dissolution in DES-2. The content of phenolic and total hydroxyl groups of the regenerated lignin increased, with reduction in their average molecular weights and polydispersity, indicating that the dissolution and regeneration of lignin in these ternary DESs can make it more homogeneous. The regenerated lignin was partially replacing for polyols in the LRPUF synthesis, the lignin replacement rate could up to 58.6% with good mechanical properties. The findings add to our understanding for efficient dissolution of lignin in DESs and for synthesizing the highly LRPUF.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMACROMOLECULES
·
2020
·
IF 6.092
Yijie Zhou,Yong Qian,Jingyu Wang,Xueqing Qiu,Hongbo Zeng
UV filters that contain one or two aromatic rings in conventional sunscreens generally have a poor photo- and thermal stability and can easily penetrate through stratum corneum and dermis into the blood vessel, thus causing potential health-threatening issues. Herein, a series of bioinspired photostable and biocompatible polydopamine-grafted lignin (AL-PDA) with strong bioadhesion have been synthesized through free radical addition of dopamine (DA) and alkali lignin (AL). AL-PDA was used to emulsify organic UV filters and further cross-linked to form nanocapsules through ultrasonic cavitation. The retention rate of optimal AL-PDA nanocapsules on the skin surface reached 87% after a thorough rinse with water and negligible penetration was observed, which demonstrates their excellent bioadhesion property. Force measurements using atomic force microscopy (AFM) quantitatively revealed the adhesion between the nanocapsules and skin. An average DA grafting number of 4 would be required to endow the AL-PDA nanocapsules with suitable water-penetration resistance. The nanocapsules were used as the sole active ingredient for formulating sunscreen, whose sun protection factor (SPF) value could reach 195.33 with a dosage ∼10 wt % lasting for over 8 h under UV radiation. The as-prepared nanocapsules possess excellent antioxidant capacity and biocompatibility, ensuring their superior performance and safe use in the sunscreen. This work provides new insights into the development of biomass lignin for advanced function materials and high-end products.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Green Energy & Environment
·
2020
·
IF 6.395
Linlin Fan,Zhiqiang Shi,Qingjuan Ren,Lei Yan,Fuming Zhang,Liping Fan
Nitrogen-doped lignin-based carbon microspheres are synthesized using 3-aminophenol as a nitrogen source by the hydrothermal method. The structural change and the effect on the electrochemical properties are systematically investigated. Nitrogen-doped lignin-based carbon microspheres represent well-developed spherical morphology with many active sites, ultramicroporous (< 0.7 nm) structure, and large interlayer spacing. Consistent with the obtained physical structures and properties, the nitrogen-doped carbon microspheres exhibit fast sodium ion adsorption/intercalation kinetic process and excellent electrochemical performance. For example, a reversible specific capacity of 374 mAh g −1 at 25 mA g −1 with high initial coulombic efficiency of 85% and high capacitance retention of 90% after 300 cycles at 100 mA g −1 and stable charge/discharge behavior at different current density is obtained. The additional defects and abundant ultramicroporous structure can enhance sloping capacity, and large interlayer spacing is considered to be the reason for improving plateau capacity.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 137
·期 44
·49354
·
IF 2.52
Xin Ge,Mingming Chang,Wei Jiang,Bangwen Zhang,Ruiguang Xing,Chaoke Bulin
In this work, biodegradable lignin/poly(lactic acid) (PLA) blends were prepared with melting compounding method. Dicumyl peroxide (DCP) and maleic anhydride (MA)/biphenyl peroxide (BPO) were used for the modification of the polymer blends, respectively. Structure of the polymer blends was characterized with Fourier transformed infrared spectroscopy and field emission scanning electron microscopy. Mechanical properties of the samples were determined with universal test machine and dynamic mechanical analysis. Thermal behaviors and thermal stability of the blends were all characterized with a thermal gravimetric analysis/differential scanning calorimetry simultaneous thermal analyzer. Lignin reinforced the mechanical strength of the blends while the thermal stability was not improved. At low content, DCP and MA/BPO apparently enhanced the mechanical strength of lignin/PLA blends. However, excessive DCP led to decreased tensile strength and elongation at break. Both DCP and MA/BPO resulted in lower glass transition temperature and melting temperature of PLA in the blends, while the thermal stability of the polymer blends was poorer after modification.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）