CHINESE JOURNAL OF CHEMISTRY
·
2016
·Vol. 34
·期 7
·657-661
·
IF 1.872
Zhengyi Li,Jinbei Yan,Yue Yin,Zhihui Zhang,Zhiming Wang,Defeng Xu,Xiaoqiang Sun
A simple and nontoxic fluorescent chemosensor of di- O -methyl curcumin has been prepared from curcumin. The sensor exhibited selective and sensitive fluorescent responses toward Al 3+ over a wide range of metal ions, such as Mn 2+ , Ce 3+ , Pt 2+ , Sn 4+ , Hg + , Sb 3+ , K + , Ca 2+ , Mg 2+ , Ba 2+ , Cu 2+ , Ni 2+ , Na + , NH 4 + , Ag + , Pb 2+ , Zn 2+ , Fe 2+ , Fe 3+ , Hg 2+ and Cr 3+ in ethanol/water. The free ligand showed quite weak fluorescence emission due to the isomerization of CO double bond in the excited state, however, after addition of Al 3+ , fluorescence emission results in a prominent fluorescence enhancement.
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FOOD CHEMISTRY
·
2017
·
IF 4.529
Lei Zhou,Zhiqiang Xiong,Wei Liu,Liqiang Zou
Gentisic acid and cyanidin-3-O-glucoside are important bioactive polyphenols which are widely distributed in many fruits and cereals. In this work, kinetic study, spectral analysis and computational simulation were used to compare the inhibitory effects and inhibition mechanisms of gentisic acid and cyanidin-3-O-glucoside on mushroom polyphenoloxidase (PPO). The inhibitory effect of cyanidin-3-O-glucoside on PPO was much stronger than that of gentisic acid. Gentisic acid inhibited PPO in a reversible mixed-type manner while cyanidin-3-O-glucoside was an irreversible inhibitor. Gentisic acid and cyanidin-3-O-glucoside made the thermal inactivation of PPO easier, and induced apparent conformational changes of PPO. Compared with gentisic acid, cyanidin-3-O-glucoside had stronger effects on the thermal inactivation and conformation of PPO. Molecular docking results revealed gentisic acid bound to the active site of PPO by hydrogen bonding, π–π stacking and van der Waals forces. However, cyanidin-3-O-glucoside might irreversibly interact with the Met or Cys in PPO by covalent bonds.
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CARBOHYDRATE POLYMERS
·
2017
·
IF 4.811
Zhen Zhang,Fujun Jin,Zicong Wu,Ju Jin,Feng Li,Yiliang Wang,Zhiping Wang,Shunqing Tang,Chaoxi Wu,Yifei Wang
Chitosan nanofibers (CSNFs) have potential applications in biomaterials, oil recovery and food packaging, but their instability in moist environment has limited their full utilization. Here we report that CSNFs can be O-acylated in a post-electrospinning treatment by using pyridine as catalyst and short-chain (C2, C3, C4, C5 and C6) and long-chain (C8 and C12) fatty acid anhydrates as acylation agents. The effects of O-acylation to CSNFs were analyzed in detail. FT-IR, 1 H NMR and elemental analysis indicated that the hydroxyl groups of chitosan in CSNFs were acylated in 2 h. XRD spectra indicated that the O-acylation modification altered the crystal structure of the native fibers and the acyl substituents packed in a laterally aligned and layered structure. SEM examinations showed that the acylation modification could effectively control the fibrous structure of CSNFs and improve their stability in moist environment. The O-acylated CSNFs generally have an average diameter about 100 nm except for laurelated CSNFs (∼200 nm). Water contact angle measurement indicated that the wetting properties of O-acylated CSNFs were affected by the length of acyl side chains. This fiber acylation strategy can tune the material properties of CSNFs and expand their potential applications.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Wenchen Ren,Huanxi Wang,Qianlin Zhang,Mengchi Chen,Zhongrui Li,Huan Guo,Jing Bai,Xiaomin Dai,Santosh Kumar Verma,Yunhua Xu
In this paper, petal sheet layered Co-Al bimetallic hydroxides were prepared using the hydrothermal method using methanol as a solvent. Pt/Co-Al-O catalysts were produced after the impregnation method and H 2 reduction. This catalyst was applied to the dehydrogenation reaction process of methylcyclohexane to toluene. A fixed-bed reaction device carried out comparative tests of this series of catalysts, and the effect of Co addition on the performance of Pt/Co-Al-O catalysts was investigated in detail. Among them, the Pt/Co 3 -Al 1 -O catalyst showed the best performance with high toluene selectivity throughout the dehydrogenation process. The MCH conversion started to be greater than 90% at 330 °C, and the hydrogenolysis rate was 262.7 mmol/g Pt /min. The conversion gradually increased with the reaction temperature, and the conversion could reach 99.5% at 410 °C. The appropriate introduction of Co element can reduce the excessive strong acidic sites of Al 2 O 3 itself and retain a certain number of weak acidic sites, while the bimetallic hydroxide carrier improves the dispersibility of the active component, reduces its particle size, and forms a certain strong interaction between the carrier and Pt. The final conversion of the catalyst decreased by about 2% in the 100 h stability test at 380 °C, which indicated that the Pt/Co 3 –Al 1 –O catalyst had strong coking resistance and good stability. These results indicate that the Pt/Co–Al–O series catalysts have potential industrial applications in hydrogen energy utilization.
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Small
·
2024
·Vol. 20
·期 29
·2310563
·
IF 13
Pengfei Li,Shanshan Xue,Lu Sun,Xiaobao Ma,Wenning Liu,Li An,Yichang Liu,Dan Qu,Zaicheng Sun
Carbon dots (CDs) have received considerable attention in many application areas owing to their unique optical properties and potential applications; however, the fluorescent mechanism is an obstacle to their applications. Herein, three-color emissive CDs are prepared from single o -phenylenediamine (oPD) by regulating the ratio of ethanol and dimethylformamide (DMF). Fluorescent mechanism of these CDs is proposed as molecular state fluorescence. Reaction intermediates are identified using liquid chromatrography–mass spectroscopy (LC–MS) and 1 H nuclear magnetic resonance (NMR) spectra. 1H-Benzo[d]imidazole (BI), 2,3-diaminophenazine (DAP), and 5,14-dihydroquinoxalino[2,3-b] phenazine (DHQP) are proposed to be the fluorophores of blue, green, and red emissive CDs by comparing their optical properties. As per the LC–MS and 1 H-NMR analysis, DHQP with red emission tends to form from DAP and oPD in pure ethanol. By adding DMF, BI formation is enhanced and DHQP formation is suppressed. The prepared CDs exhibit green emission with DAP. When the DMF amount is >50%, BI formation is considerably promoted, resulting in DAP formation being suppressed. BI with blue emission then turns into the fluorophore of CDs. This result provides us an improved understanding of the fluorescent mechanism of oPD-based CDs, which guides us in designing the structure and optical properties of CDs.
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Molecular Catalysis
·
2024
·
IF 3.9
Xiaoyu Yan,Xiaoqing Xu,Yuhan Sun,Xiuyi Li,Jiale Xu,Renjie Ji,Rui Huang,Chunyi Li
Compared with propane dehydrogenation (PDH) technology, oxidative dehydrogenation (ODH) of propane is an effective way to break through the thermodynamic constraints, which has changed the endothermic reaction into exothermic. Meanwhile, coking in PDH was significantly reduced by the presence of an oxidant in ODH of propane. Therefore, ODH of propane has attracted wide interest and has been studied in recent years. However, the contradiction between the conversion of propane and the selectivity of propene was the intrinsic problem of ODH of propane that required further study. In this work, a novel aluminum/potassium-doped mixed metal oxide catalyst Mo 1 V 0.5 Al 0.02 K 0.03 O x was synthesized using a simple co-impregnation method, whose selectivity for propene (83.2 %) and conversion of propane (12.7 %) at 300 °C were the best among all other alkali metal/alkaline-earth metal-doped catalysts. The further discussion illustrated that doping potassium and alumina could synergistically adjust the density of acid sites on the catalyst, establishing an equilibrium between high propane conversion and the ideal propene selectivity. After modification, the density of Brønsted acid decreased, leading to an enhancement in the selectivity of propene. Simultaneously, the addition of steam in the feed gas promotes propene to oxygenates and improves the conversion of propane under the condition of constant contact time.
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ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2018
·
IF 3.584
Jie Zhang,Lei Wang,Chuang Li,Shaohua Jin,Changhai Liang
Direct selective hydrogenolysis of dibenzofuran (DBF) derived from coal and shale oil to a value-added chemical, ortho-phenylphenol (OPP), with high selectivity (80%) and yield (48%) has been achieved over Pt/MgO at 400 °C and 1.0 MPa by controlling the C–O bond cleavage as well as minimizing the extent of hydrogenation of aromatic rings. Meanwhile, Pt/SiO2, Pt/Al2O3, and Pt/MgO/Al2O3 catalysts were used for the DBF hydrogenolysis and showed lower selectivity for OPP. The influence of reaction parameters has been studied to unveil the optimal reaction conditions. And the phenomenon of OPP dehydrogenation is found over various catalysts for the hydrogenation reaction of OPP. Extensive reactions and catalyst characterizations demonstrated that the OPP selectivity and the dehydrogenation of OPP to DBF follows the order of supports basicity: MgO-900 > MgO > SiO2 > MgO/Al2O3 > Al2O3, which shows that the acid–base properties of supports impact the adsorption and desorption behaviors of DBF and OPP, and results in the disparity of OPP selectivity and the dehydrogenation of OPP. Finally, a plausible reaction pathway and mechanistic understanding are proposed.
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JOURNAL OF POLYMER SCIENCE
·
2025
·
IF 3.6
Shufang Wu,Zhiqian Long,Yushu Zhang,Ting Zhang,Qinghong Luo,Xiaoxuan Liu,Zhiquan Li
Using low catalyst loadings while maintaining precise polymer property control is a critical challenge in the O-ATRP field. Herein, we report a novel O-ATRP system utilizing 1-bromopyrene (Py-Br) as a photoredox catalyst, enabling controlled polymerization of methyl methacrylate (MMA) at an ultra-low loading of 10 ppm. When combined with ethyl α -bromophenylacetate (EBPA) as an initiator, this system produces polymers with a molecular weight distribution of 1.48 and an initiation efficiency of 66.7%. Mechanistic studies, including UV–Vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and time-resolved fluorescence measurements, elucidate the photophysical and photochemical properties of Py-Br in O-ATRP. Kinetic analyses reveal first-order polymerization kinetics, while the linear increase of molecular weight with monomer conversion and low dispersity values indicate good control over the polymerization. The living nature of the system is further confirmed through successful chain extension experiments. This Py-Br-catalyzed O-ATRP system explores the feasibility of conducting polymerization at lower catalyst concentrations, offering insights into approaches for reducing catalyst usage in polymer synthesis. Graphical Photoinduced metal-free ATRP of MMA using ppm-level Py-Br as the organic photocatalyst.
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ChemistrySelect
·
2025
·Vol. 10
·期 6
·e202405266
·
IF 2
Boao Du,Lihui Zheng
Graphical This research focuses on supercapacitor electrode materials. Using Rhus typhina leaves as raw materials, it innovatively employs a mixed activator of K 2 CO 3 and ZnCl 2 Through a two-step carbonization-activation method, O/N self-doped TLMPC-x is prepared. Among them, TLMPC-1.0 exhibits outstanding performance, with a large specific surface area, high specific capacitance, and strong cycle stability, demonstrating promising application prospects. This research focuses on the field of supercapacitor electrode materials. Using Rhus typhina leaves as the starting material, it innovatively applies a mixed activator composed of K 2 CO 3 and ZnCl 2 and successfully prepares O/N self-doped leaf-derived porous carbon electrode materials (TLMPC-x) through a precisely controlled two-step carbonization-activation method. The aim is to develop a new type of electrode material that combines excellent performance, environmental friendliness, and the advantage of low cost, and to deeply explore the mechanism of the effect of the activator ratio on the specific surface area and electrochemical performance of the materials. Among them, TLMPC-1.0 remarkably exhibits a specific surface area as high as 2827.9 m 2 g −1 . Its abundant and multi-level pore structure complements well with the diverse heteroatom doping. During the electrochemical performance test in the KOH electrolyte system, the specific capacitance of this material excellently reaches 335.3 F g −1 , and the capacitance retention rate is stably maintained at 69%. When the power density is 250 W kg −1 , an energy density of 9.45 Wh kg −1 can be achieved. Moreover, after 20 000 charge–discharge cycles, its capacitance retention rate is still as high as 96.4%, demonstrating extremely excellent electrochemical performance and ultra-stable cycle stability.
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ACS Omega
·
2025
·
IF 4.3
Baoyang Dai,Shanshan Yan,Zhimi Chen,Tucai Zheng,Jie Qin,Junhua Zhao,Wanting Jin,Chunhui Zhou,Li Wan,Xing Su,Chuanhua Gao
Perovskite quantum dots (QDs) exhibit unique advantages, including a wide color gamut, narrow full width at half-maximum, cost-effectiveness, and high-efficiency luminescence, positioning them as a significant focus in contemporary optoelectronic research. Nevertheless, the synthesis of QDs often introduces crystal defects, while conventional in situ ligands can detrimentally affect the optoelectronic properties of perovskites. To overcome these challenges, we synthesized a symmetrical silane-based passivating agent containing phosphorus–oxygen double bonds. This agent enabled the in situ passivation of perovskites, significantly improving their optical performance and stability. Results showed that postpassivation QDs demonstrated bright green photoluminescence (PL) at 525 nm, with a 28% enhancement in PL intensity, a 16% increase in photoluminescence quantum yield, and an average lifetime (τave) extended by 191.2 ns. Furthermore, the thermal stability at 80 °C improved by 3.75-fold, and the stability under 84% relative humidity conditions increased by 21%. 1,3-bis(3-diethoxyphosphorylpropyl)-1,1,3,3-tetramethyldisiloxane (SPE)-passivated perovskites are viable for practical applications.
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AICHE JOURNAL
·
2025
·
IF 4
Xiao-Ling Tang,Kang Zhao,Teng-Kun Huang,Bai-Hua He,Xu-Gang Zhang,Zhi-Qiang Liu,Yu-Guo Zheng
O -Succinyl- L -homoserine mercaptotransferase (MetZ) is a key enzyme for the synthesis of L -methionine. However, the limited tolerance to high concentrations of substrate methyl mercaptan sodium restricts its industrial applications, while the “trade-off” between activity and stability has always been a challenge for protein engineering. To address this problem, a strategy of dynamic network rigidification-local flexibility regulation was applied in this study to engineer the enzyme from Chromobacterium violaceum ( Cv MetZ). Through consensus sequence analysis and structure-guided design, the hotspot amino acid residues were anchored for mutagenesis. The best mutant T59I/T119Y/A241T was obtained with synergistic enhancement of activity and stability. The half-life ( t 1/2 ) of whole cells harboring the mutant was increased from 3.3 and 1.3 h to 20.6 and 7.2 h, in the presence of 5% and 10% methyl mercaptan sodium, respectively. The engineered enzyme was successfully immobilized with ideal usability, which laid the foundation for efficient and scale-up bioproduction of L -methionine.
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Molecular Catalysis
·
2024
·
IF 3.9
Chi Ma,Zhiyong Zhong,Quanjun Xiang
The photocatalytic efficiency of bismuth-based metal-organic framework (Bi-MOF) is extremely restricted by the rapid recombination of photogenerated electron-hole pairs, which reduce the number of electrons involved in the photocatalytic reduction reaction. Constructing precise interfacial bond bridges between metal nanoparticles (NPs) and MOFs has emerged as an effective strategy to address the above-mentioned issues, promoting the electrons transfer. Herein, this study improves the sluggish dynamics of photogenerated charge in Bi-MOF by inducing the Pd-O-Bi bond bridges at the interface on a Pd NPs-decorated Bi-MOF (Pd/Bi-MOF) nanosheets. This phenomenon results in an interaction between Pd NPs and the Bi-MOF support. And Pd-O-Bi bond bridges provide the fast electron transfer channels, triggering the directional migration of photogenerated electrons from Pd to Bi node, then enhancing the spatial separation of photogenerated electron-hole pairs, finally facilitating overall photocatalytic CO 2 reduction. The presence of these bond bridges leads to higher enhancement in CO production for Pd/Bi-MOF nanosheets compared to the Bi-MOF nanosheets under visible light irradiation after 4.5 h. This research demonstrates the importance of interfacial bond bridges and provides a reasonable guide to design efficient photocatalyst for reduction of CO 2 to CO.
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