RESEARCH ON CHEMICAL INTERMEDIATES
·
2017
·Vol. 43
·期 7
·3961-3974
·
IF 1.369
Jiao Yinchun,Zhu Man,Deng Renjie,Jian Jian,Yin Yi,You Kuiyi
With the increase in environmental awareness, developing a highly efficient and environmentally benign nitration process has very important academic and applied industrial values in the synthesis of nitro-compounds. Towards this goal, we have developed an efficient and environmentally friendly approach for solvent-free liquid phase nitration of toluene by employing NO 2 as a nitrating agent and sulfated SO 4
2− /WO 3 as a catalyst replacing traditional nitric acid–sulfuric acid under mild conditions. The results indicate that SO 4
2− /WO 3 as an effective and eco-friendly catalyst exhibits excellent catalytic activity and reusability for the nitration of toluene with NO 2 . In addition, the possible pathway for liquid phase nitration of toluene with NO 2 over sulfated SO 4
2− /WO 3 catalyst was suggested. The present method makes this nitration process safe and environmentally friendly, and has the potential to enable a sustainable production of nitro-compounds from the liquid phase nitration of aromatic hydrocarbon with NO 2 in industrial applications.
研究领域:
催化化学
·
绿色化学
·
有机合成
·
环境友好工艺
·
工业化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Zhuo Zhang,Xiaoming Duan,Baofu Qiu,Zhihua Yang,Delong Cai,Peigang He,Dechang Jia,Yu Zhou
Textured hexagonal boron nitride (h-BN) matrix composite ceramics were prepared by hot pressing using 3Y 2 O 3 -5Al 2 O 3 (mole ratio of 3:5) and 3Y 2 O 3 -5Al 2 O 3 -4MgO (mole ratio of 3:5:4) as liquid phase sintering additives, respectively. During the sintering process with liquid phase environments, platelike h-BN grains were rotated to be perpendicular to the sintering pressure, forming the preferred orientation with the c -axis parallel to the sintering pressure. Both h-BN matrix ceramic specimens show significant texture microstructures and anisotropic mechanical and thermal properties. The h-BN matrix ceramics prepared with 3Y 2 O 3 -5Al 2 O 3 -4MgO possess higher texture degree and better mechanical properties. While the anisotropy of thermal conductivities of that prepared with 3Y 2 O 3 -5Al 2 O 3 is more significant. The phase compositions and degree of grain orientation are the key factors that affect their anisotropic properties.
研究领域:
材料科学
·
无机非金属材料
·
先进陶瓷
·
热管理材料
·
结构功能一体化材料
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 9
·2268-2275
·
IF 5.106
Nan Wang,Xinjun Li
A novel photocatalyst with protonated carbon nitride (p-C3N4) loaded with IrO2 quantum dots (QDs) was fabricated via a facile hydrothermal method. Structure characterization studies (XRD, STEM, XPS, UV–vis spectra and PL spectra) revealed that the IrO2 QDs with an average diameter of ca. 2 nm were highly dispersed and anchored to the surfaces of p-C3N4. The introduced IrO2 QDs promoted the electron–hole separation efficiency of p-C3N4 and increased the absorbance capacity within the visible light range. The photocatalytic activity was evaluated using hydrogen and oxygen evolution from water splitting under visible light illumination. The optimum IrO2/C3N4-0.6 wt% photocatalyst exhibits the highest hydrogen evolution rate of 45 μmol h−1 and oxygen production rate of 20 μmol h−1. Under visible light irradiation, the composite photocatalyst shows higher photocurrents, more negative onset potential and lower photoluminescence intensity compared with those of p-C3N4, which demonstrated that the modification of IrO2 QDs accelerated the transformation, separation, and utilization of photoelectrons and thereby significantly improved the photocatalytic performance.
研究领域:
光催化化学
·
纳米材料科学
·
能源转化技术
✓ 已验证
DOI
高影响因子
COMPOSITES COMMUNICATIONS
·
2018
·
IF 0
Fang Fang,Pingan Song,Shiya Ran,Zhenghong Guo,Hao Wang,Zhengping Fang
In this paper, we have reported a facile way to functionalize graphene oxide (GO) via assembling a supermolecular aggregate of piperazine (PiP) and phytic acid (PA) onto the GO surface (PPGO) without using any organic solvent . The functionalization of GO is confirmed by the X-ray photoelectron spectrum (XPS), transmission electron micrographs (TEM) and Raman spectrum . The introduction of 3 wt% PPGO into epoxy resin (EP/PPGO3) results in notable suppression on the fire risk of epoxy resin . In addition, cone calorimeter tests showed that the peak heat release rate (pHRR) was decreased from 727.4 kW/m 2 to 367.5 kW/m 2 (49%), and the peak smoke production rate (pSPR) was decreased from 0.2316 m 2 /s to 0.1379 g/s (40%). The improved flame-retardant performance of EP nanocomposites is most likely due to a tripartite cooperative effect from the key components (piperizine, phytic acid, and GO). This strategy demonstrates a facile and efficient approach for fabricating highly effective graphene-based flame retardants for polymers.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
JOURNAL OF ORGANIC CHEMISTRY
·
2020
·
IF 4.335
Shimin Xie,Lebin Su,Min Mo,Wang Zhou,Yongbo Zhou,Jianyu Dong
An alternative thioesterification reaction via copper-catalyzed oxidative coupling of readily available aroylhydrazides with disulfides is developed, in which oxidative expulsion of N2 overcomes the activation barrier between the carboxylic acid derivatives and the products. The reaction produces various thioesters in good to excellent yields with good functional group tolerance. In the reaction, stable and easily available aroylhydrazides are used as acyl sources and the relatively odorless disulfides are used as S sources. Mechanistic investigations demonstrate that the reaction of copper salt and oxidant (NH4)2S2O8 allows for achievement of tandem processes, including deprotonation, free-radical-mediated denitrogenation, and C–S bond formation.
研究领域:
有机化学
·
催化反应
✓ 已验证
DOI
高影响因子
CHINESE PHYSICS LETTERS
·
2024
·
IF 3.5
Longfu Li,Lei Shi,Lingyong Zeng,Kuan Li,Peifeng Yu,Kangwang Wang,Chao Zhang,Rui Chen,Zaichen Xiang,Yunwei Zhang,Huixia Luo
Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature (Tc) of the parent superconducting materials. Herein, a new simple urea approach is developed to synthesize the N-doped α-Mo2C. Benefiting from the simple urea method, a broad superconducting dome is found in the Mo2C1-xNx (0 ≤ x ≤ 0.49) compositions. XRD results show that the structure of α-Mo2C remains unchanged and that there is a variation of lattice parameters with nitrogen doping. Resistivity, magnetic susceptibility, and heat capacity measurement results confirm that the superconducting transition temperature (Tc) was strongly increased from 2.68 K (x = 0) to 7.05 K (x = 0.49). First-principles calculations and our analysis indicate that increasing nitrogen doping leads to a rise in the density of states at the Fermi level and doping-induced phonon softening, which enhances electron-phonon coupling. This results in an increase in Tc and a sharp rise in the upper critical field. Our findings provide a promising strategy for fabricating transition metal carbonitrides and provide a material platform for further study of the superconductivity of transition metal carbides.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xingchao Zhang,Ruoyu Zhang,Siying Niu,Jiming Zheng,Chongfeng Guo
The MoS 2 /g-C 3 N 4 heterojunction composite (marked as MoS 2 /g-C 3 N 4 -H) was successfully prepared via calcining the melamine coated MoS 2 nano-sphere, where the thin g-C 3 N 4 nano-sheets were tightly grown on the surface of MoS 2 nano-sphere to form MoS 2 inlaying in g-C 3 N 4 heterostructure. The detailed charge transfer mechanism was discussed by combining theoretical calculation and experiments, in which the intrinsic cause of photo-generated charge separation and transfer was determined as the directional built-in electric field driven by different Fermi levels of MoS 2 and g-C 3 N 4 . Comparatively, the enhanced photo-catalytic performance and stability of the sample were assessed by degrading the Rhodamine (RhB) and reducing the Dichromate (Cr 6+ ) solutions under the irradiation of the simulated sunlight, which could be attributed to the widened spectral absorption range and improved electron-hole separation rate. Based on above results, the photo-catalytic mechanism involving redox reactions was also clearly proposed.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
BIOSYSTEMS ENGINEERING
·
2021
·
IF 4.123
Jiyong Shi,Yueying Wang,Zhihua Li,Xiaowei Huang,Tingting Shen,Xiaobo Zou
Nitrogen (N), magnesium (Mg), and potassium (K) deficiency all result in the decrease of chlorophyll density (CH.D) in cucumber leaf, but it is difficult to differentiate N/Mg/K-deficient leaves using CH.D. New nutrient indicators based on CH.D distribution features of the whole cucumber leaf were proposed to simultaneously diagnose N/Mg/K-deficient cucumber plants. CH.D distribution map in N/Mg/K-deficient and control leaves were determined non-destructively using hyperspectral imaging with the wavelength range of 430–960 nm. Compared with the CH.D distribution map of control group leaves, a decrease in CH.D could be observed on the whole area of N-deficient leaves, Mg-deficient leaves presented pixels with low CH.D between main leaf vein, and pixels with low CH.D at the border of K-deficient leaves. Distribution features were extracted from the CH.D distribution map and were employed to diagnose N/Mg/K-deficient leaves simultaneously, with the diagnostics rates of 96.67%. The results indicated that CH.D distribution features can realize the simultaneous diagnosing in the early stage of N/Mg/K deficiency and timely guidance of top dressing is of great significance to increase yield.
研究领域:
植物营养学
·
农业遥感
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Yuan Sang,Xinqi Guan,Hailing Liu,Jiang Yang,Shengke Li,Qiannian Wang,Xiaoxi Huang,Yiming Wang,Qiang Yu,Mengyu Li
The chemical modification of lignin has been hindered by its poor solubility; therefore, expensive polar solvents are required. Herein, this article reports a solvent-free CuAAc reaction on lignin modification through ball-milled mechanochemistry, which avoids solvent use. In this way, not only is the cost reduced but also the reaction goes on the green side. In detail, the hydroxyl groups of lignin are first modified to alkyne end groups. Then, the lignin-alkyne and ethyl azidoacetate are ball-milled with a catalyst of Cu(OAc)2 in a solvent-free condition at 600 rpm. This reaction reached full conversion within 30 min on lignin model compounds of vanillin, 2-methoxy-4-methylphenol, and 2-methoxy-4-propylphenol. For natural lignins, the reaction reached 89% conversion for enzymolysis lignin-alkyne and 93% conversion for dealkali lignin-alkyne within 30 min. Despite intense impact energy in the planetary ball mill, the lignin polymer structure remained intact rather than degraded through the gel permeation chromatography (GPC) study. Then, the ball mill reaction condition was optimized to a 1:1.2 lignin-alkyne to ethyl azidoacetate ratio. The reaction time was minimized to 20 min, and mill balls were optimized to 40 balls of a 3 mm diameter. Lastly, a bunch of azide compounds was reacted with enzymolysis lignin-alkyne, including benzyl azide, 4-azidobenzonic acid, and 1-(azidomethyl)pyrene. 1-(Azidomethyl)pyrene enabled lignin to become a fluorophore. A polymer example, PEG-N3, was grafted onto lignin-alkyne through this solvent-free ball-milled CuAAc. In addition, a bisazide compound, 1,8-diazido-3,6-dioxaoctane, cross-linked lignin into macroscopic flakes. Moreover, the ball mill and solvent syntheses are analyzed metrically to evaluate the green chemistry.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2021
·Vol. 8
·期 5
·055504
·
IF 1.62
Fengpo Yan,Hao Zhang,Yu Zhang,Fugui Yang
0.3 mol% platinum loaded g-C3N4 sample was prepared by photoreduction method to study the long-term stability of photocatalysts. For the first time, we have discovered the oriented attachment (OA) mechanism growth of Pt nanoparticles on g-C3N4 solid surface, which is completely different from Ostwald ripening (OR) or particle migration and coalescence (PMC) that previously reported. The Pt nanoparticles perform Brownian motion on the surface of g-C3N4 support under the collision of liquid molecules, then two or more nanoparticles attach together via the crystallographic orientation to construct larger ones. Al2O3 film prepared by atomic layer depositon was introduced to inhibit the Brownian motion of Pt nanoparticles. It is found that as the increase of the Al2O3 growth cycles, the photocatalytic hydrogen production of Pt/g-C3N4 coated by Al2O3 increase from 1.14 mmolg−1h−1 to 2.08 mmolg−1h−1 and then decrease to 1.4 mmolg−1h−1, and the apparent quantum efficiency (QE) also increase from 1.2% to 2.1% and then decrease to 1.4%. Meanwhile, the long-term stability of photocatalyst always increases. This work has revealed new pathway of photocatalytic nanoparticle growth on solid surface and proposed the method to prevent it.
研究领域:
材料科学
·
光催化
✓ 已验证
DOI
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2022
·Vol. 86
·期 8
·1876-1886
·
IF 2.43
Qin Yingzhi,Zhang Xin,Yuan Guang-En
In this study, low concentration of ferrous ions (Fe 2+ ) was added into natural molybdenite (MDN) activated peroxymonosulfate (PMS) process to degrade a typical azo dye, orange G (OG). It was found that the addition of Fe 2+ promoted OG degradation and simultaneously reduced the leaching of toxic Mo ions significantly. Further, the utilization efficiency of MDN was improved immensely, which was estimated from reuse experiment. MDN mainly acted as the reductant to promote cycling of Fe 3+ /Fe 2+ redox couple through reducible sulfur and Mo(IV) on its surface. Sulfate radicals (SO 4 •- ), hydroxyl radical (•OH) and singlet oxygen ( 1 O 2 ) were verified as the main reactive oxygen species responsible for OG degradation by scavenging tests and electron paramagnetic resonance. Some experiment parameters, such as MDN dosage, Fe 2+ concentration, PMS concentration, initial solution pH and coexisting anion, all affected OG degradation efficiency. In a word, this work provides a new method of enhancing PMS activation by MDN using low concentration of Fe 2+ for degradation of organic pollutants in water. MDN was applied as an efficient co-catalyst for permonosulfate activation. The sulfur element on MDN surface was able to reduce generated Fe 3+ . , , and were responsible for the removal of OG in MDN/Fe 2+ /PMS system. The Fe 2+ was demonstrated to promote the reusability of MDN.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Guohao Zhu,Ze Li,Hao Guo,Guangchao Li,Youbin Zheng,Xin Liu,Haijun Pan,Liang Dong,Jianbing Zang,Shaopei Jia
Despite having a similar electronic structure to Pt, TiN exhibits poor catalytic activity for oxygen reduction reaction (ORR). Doping transition metal (M) atoms into TiN can enhance its ORR catalytic activity by creating MN x structures similar to those found in M and N codoped carbon materials . Notably, TiN demonstrates better stability than carbon materials. Herein, a hybrid of M-doped TiN and N-doped carbon nanofibers (M-TiN/NCNFs) was prepared via electrospinning followed by thermal treatment. Among the prepared M-TiN/NCNFs, Fe-TiN/NCNFs exhibited the highest ORR catalytic activity and excellent stability. The FeN 5 structure in Fe-TiN/NCNFs was identified as the active site. Density functional theory calculations indicated the moderate interaction between Fe and O (Fe–O bond) is a key factor for the optimal ORR catalytic activity of Fe-TiN/NCNFs. The number of antibonding electrons in molecular orbital of M–O bond can serve as a descriptor for distinguishing the ORR catalytic activities of M-TiN/NCNFs.
研究领域:
材料科学
·
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）