GIANT
·
2024
·
IF 5.4
Xin Guan,Zhiheng Zhou,Xinzhen Fan,Wenchao Xu,Yijie Jin,Chuanzhuang Zhao
α -Methyl groups play significant roles in the regulation of water molecules within both small molecular systems and bio-macromolecular systems. Systematically studying the influence of α -methyl on the dynamics of water molecules within hydrogel systems is therefore worthwhile. In this study, we prepared a series of hydrogen-bonded (H-bonded) hydrogels with varying densities of α -methyl groups by copolymerizing methacrylamide (MAm) with its α -methyl-absent analogue, acrylamide (Am). Introducing a small amount of Am (≤6 mol%) into the polymer chain resulted in significant shifts in the viscoelasticity of the hydrogels. The hydrogels exhibit a “time-temperature- α -methyl equivalence”, meaning that introduction of α -methyl-absent monomer has effects similar to elevating temperature and prolonging observation time on the dynamic properties. Based on low-field nuclear magnetic resonance spectroscopy and Raman scattering, a “hydrophilic defects-assisted H-bonds dissociation” mechanism is proposed, depicting that the α -methyl-absent monomer can disturb the rearrangement of water molecules surrounding the polymer chain and accelerate chain dissociation. These findings enabled the copolymer hydrogels with functions such as fast self-healing and tunable interface adhesion.
研究领域:
材料科学
·
生物物理学
✓ 已验证
DOI
高影响因子
Chemical Engineering and Processing-Process Intensification
·
2020
·
IF 3.731
Lan Jiang,Guang-Wen Chu,Ya-Zhao Liu,Wei Liu,Li-Xiong Wen,Yong Luo
A rotating packed bed (RPB) reactor with excellent mass transfer performance can be applied for catalytic reactions. However, the structure of catalyst particles randomly inside the rotor of the RPB reactor was easily deformed under the centrifugal field. In this work, a cordierite (COR) monolithic catalyst with high mechanical strength was prepared, aiming to be used in the RPB reactor for hydrogenation. The acid pretreatment and Al 2 O 3 coating were employed to increase the specific surface area of COR substrate. Active component palladium (Pd) was deposited on Al 2 O 3 /COR. Hydrogenation of α-methylstyrene (AMS) was selected as a model reaction for the RPB reactor with the above Pd/Al 2 O 3 /COR. Experimental results show that the space time yield (STY) in the RPB reactor was effectually enhanced 9.2 times higher than that in the fixed bed reactor at the operation conditions of 30 °C and 0.2 MPa, which shows potential prospects of the RPB reactor with Pd/Al 2 O 3 /COR monolithic catalyst for the process intensification of catalytic reaction.
研究领域:
化学工程
·
催化反应
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Yajie Qian,Xuefei Zhou,Yalei Zhang,Peizhe Sun,Weixian Zhang,Jiabin Chen,Xin Guo,Xiao Zhang
Calcium peroxide (CP) combined persulfate (PS) oxidation is an emerging in situ chemical oxidation (ISCO) technology for ground water remediation. Many field cases also confirm its effectiveness in ground water remediation while few research articles document it. This study investigated the performance of α-methylnaphthalene (MN) degradation by PS/CP to further understand this dual oxidant application in ISCO. Results showed that MN could be completely oxidized in 72 h with 1 g L −1 PS and 1 g L −1 CP. The degradation rates of MN increased with the increase of PS and CP concentration. MN degradation was significantly enhanced with the solution pH decrease, because CP was easier to dissolve and generated more radicals in acidic condition. Solutes in ground water including chloride ions, alkalinity and natural organic matters presented inhibitory effect on MN degradation in this dual oxidant system. Plausible mechanisms of the sulfate and hydroxyl radicals in the system were proposed based on the results of radical scavenging experiments and electron spin resonance (ESR) tests. It appeared that surface OH of CP was also responsible for the MN removal. The major oxidation products in this study were 1-naphthaldehdye, naphthalene-1-ylmethanol and 4-hydroxy-4-methylnaphthalen-1(4H)-one. To better understand PS/CP in ISCO, the degradation of MN was tested in ground water matrix, which showed satisfactory efficiency. The results of this study provided some detail information of PS/CP dual oxidant in degradation organic contaminants, which might provide some references for the application of this technology in ISCO.
研究领域:
环境工程
·
环境化学
·
污染控制
·
土壤与地下水修复
·
高级氧化技术
✓ 已验证
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2017
·Vol. 35
·期 2
·394-408
·
IF 2.007
Lv Xiao,Xiao Jun,Sun Tingting,Huo Xiaodong,Song Min,Shen Laihong
Tar is a barrier to limit the development of biomass gasification. Catalytic steam reforming experiments using α -methylnaphthalene (MNP) as a model tar compound were carried out in the two-stage reactor system (TSR). Based on response surface methodology, the effects of TSR temperatures and the molar ratio of steam to carbon (S/C) on MNP reforming performances were analyzed using the Li-modified Ni-based catalyst (NBC). The results show that the proper introduction of H 2 is able to improve significantly the MNP conversion, specially at lower temperatures. Furthermore, it is more appropriate for the modified catalysts by Li and Mg to be loaded in the first reactor due to their significant promotion to hydrocracking reactions, and it is favorable to place the Ni/Al catalyst in the second reactor for H 2 -rich gas. Additionally, the carbon deposition resistance of the NBC modified by Li exhibits better than that of the NBC modified by Mg.
研究领域:
能源化学
·
催化化学
·
可再生能源
·
生物质转化
·
气体化技术
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2024
·Vol. 27
·期 1
·30-37
·
IF 2.6
Yue Zhao,Chun-Li Hu,Peng-Fei Chen,Ming-Zhi Zhang,Jiang-Gao Mao
Ultraviolet (UV) birefringent crystals have important applications in polarizers, optical isolators and optical information processing. Crystals with large birefringence can enhance the modulation ability of light and realize the miniaturization of devices. However, the birefringence of cyanurates is often limited by the large dihedral angles between anionic groups. In this work, a chiral-driven approach is proposed for the first time to construct cyanurates with large birefringence. We combined racemic or chiral α-methylbenzylamine (α-MBA) molecules with a π-conjugated cyanurate group (CY), which led to the isolation of three organic hybrid cyanurates with wide band gaps >5.10 eV, namely, rac-α-MBACY, R-α-MBACY, and S-α-MBACY. Notably, the presence of chirality leads to a significant reduction of the dihedral angle between the α-MBA cation and (H2C3N3O3)− anion and a threefold increase in birefringence from 0.113@546 nm to 0.344@546 nm and 0.338@546 nm. The birefringence values of R-α-MBACY and S-α-MBACY exceed those of most of the cyanurates and commercial crystals, indicating their potential as UV birefringent crystals. This work provides new insights into the design and syntheses of UV birefringent materials.
研究领域:
材料科学
·
光学
·
无机化学
·
有机化学
·
晶体工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yunxiao Zhang,Qingxiang Cao,Xuelian Wu,Yonghao Xiao,Aiyun Meng,Qitao Zhang,Yuxiang Yu,Wei-De Zhang
Establishing effective non-platinum active sites on polymeric carbon nitride (PCN) remains a great demanding to achieve highly efficient photocatalytic hydrogen generation performance. Modification with molecular complex catalysts on PCN skeletons has been demonstrated as a promising strategy. Herein, hybrid photocatalytic material was successfully synthesized by modifying PCN with copper molecular ligand ( CuL, Schiff-based copper complex) via π-π stacking. Interestingly, atomically dispersed Cu is formed in CuL/PCN. Compared to PCN, the π-π stacking in CuL/PCN is beneficial for facilitating the migration of photogenerated electrons from PCN to CuL . Furthermore, photo-redox ability of the atomically dispersed Cu is regulated by the ligand (Schiff base) in CuL and the introduction of CuL provides abundant active sites to capture the photogenerated electrons, whereby the reductive reaction of H 2 O/H + to H 2 for CuL/PCN was significantly promoted. Consequently, an optimal hydrogen evolution rate of 15.90 μmol·h −1 was obtained on 3CuL/PCN, which was 2.02 times higher than that of 3.0 wt% Pt/PCN (7.86 μmol·h −1 ). More importantly, the hybrid material exhibits an outstanding conversion efficiency (90 %) and selectivity (99 %) for α-methylation of ketones by making full use of the in-situ generated H species and photogenerated holes under visible light irradiation.
研究领域:
材料科学
·
催化
·
光化学
·
无机化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）