RSC Advances
·
2016
·Vol. 7
·期 12
·6981-6987
·
IF 3.289
Jiheng Ding,Wanjun Peng,Ting Luo,Haibin Yu
The anhydride curing agent of 3,6-enodro-1,2,3,6-tetrahydrophthalic anhydride (OBPA) and the reactive epoxy diluent of furfuryl glycidyl ether (FGE) were prepared and characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The curing reaction kinetics process of an EP/OBPA/FGE epoxy system was studied by non-isothermal DSC methods. The parameters of the kinetics were calculated using the Kissinger model, Crnae model, Ozawa model and β–T (temperature–heating speed) extrapolation, respectively. In addition, the effect of FGE on the thermomechanical properties (glass transition temperature) and mechanical properties (flexural strength and the tensile strength) in the EP/OBPA/FGE were studied, indicating that when the content of FGE was 10 wt% the epoxy system reaches the best mechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2019
·
IF 1.911
Yu Ji,Tengda Zhang,Xia Gui,HaiJian Shi,Zhi Yun
The ketalization of glycerol with acetone was conducted over an ionic liquid [P(C 4 H 9 ) 3 C 14 H 29 ][TsO] (TTPT) in a batch reactor. A scheme to obtain the purified product using TTPT as a homogeneous catalyst is proposed and a maximum solketal yield of 86% is achieved at acetone/glycerol molar ratio of 6/1, reaction time of 0.5 h, reaction temperature of 303 K, catalyst amount of 5 wt% of glycerol. TTPT was recycled and reused for ten times without obvious losses in terms of quantity and activity. Furthermore, effects of various experimental parameters (stirring speed, catalyst loadings, temperature and reactant composition) on the reaction kinetics are investigated. In terms of kinetics modeling, K γ is fitted by reactant composition at the temperature range 298 K–323 K, which was a concise strategy that showed good precision in the kinetics fitting. The activation energy for this ketalization reaction was evaluated to be 28.2 kJ·mol −1 . In addition, the kinetics of the reaction at a temperature exceeding the boiling point of acetone were also studied. We believe that all the results are important for further development of a technology for the continuous synthesis of solketal.
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
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Jianguang Qi,Yufeng Hu,Weiting Ma,Haiyan Wang,Siqi Jiang,Liuyi Yin,Xianming Zhang,Zhenyu Yang,Yichuan Wang
A rapid expansion of production capacities for 1,3,5-trioxane has occurred worldwide, which requires optimizing design and operation and developing new catalysts with high activity and selectivity. Such optimizing and developing need models of phase equilibrium of reaction mixture and of reaction kinetics. Both models have to consider intermolecular forces and chemical reactions accelerated by catalysts. Reported herein are the reactions that actually determine the equilibrium concentration of 1,3,5-trioxane and control the most important side reactions and, therefore, must be taken into consideration in phase equilibrium and reaction kinetic models. On the basis of these findings, new methods and the underlying mechanisms are established to successfully resolve the dilemma that increasing catalyst activity almost always decreases its selectivity to 1,3,5-trioxane. New salt additives are developed for the industrial catalyst H 2 SO 4 , which increase 1,3,5-trioxane concentration in distillate by 23% but decrease formic acid concentration in coexisting reaction solution phase by 34%.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2021
·
IF 3.423
Lijian Song,Xiahua Zuo,Ying An,Jin Zhan,Youchen Zhang,Weimin Yang,Jing Tan,Lisheng Cheng
Dopamine (DA) has been applied in surface chemistry because of its green and simple polymerization process. However, the polymerization kinetics is slow for mass production. Herein, we proposed a novel method to increase the polymerization rate of DA significantly. The DA solution was treated by a two-step method using microwave irradiation and oxygen oxidation . As a result, the DA solution turned dark only in 6 min. The UV–vis spectra and molecular dynamics showed that microwave irradiation promotes the generation of reactive oxygen species, and the oxygen is used as a supplement to compensate for the overflow of oxygen during the microwave heating process. This study provides a new promising choice to polymerize DA quickly and will inspire related applications in various fields.
研究领域:
材料科学
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化学工程
·
生物医学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2021
·
IF 6.766
Yi-Tong Wang,Di Gao,Jie Yang,Ya-Nan Zeng,Jun-Guo Li,Ya-Jun Wang,Xiao-Man Wang,Fu-Ping Wang,Qing Yu,Tian-Ji Liu,Shuang Cai,Zhen Fang
Highly stable heterogeneous catalysts were prepared by impregnating carbonates suspension solutions onto electric furnace dust (EFD) and being calcined at high-temperature for the production of biodiesel from soybean oil. Process of impregnating with CaCO 3 , BaCO 3 , SrCO 3 and CdCO 3 suspension solutions and being calcined at high-temperature did not promote improvement of catalytic activity of EFD powder, while the single impregnating with K 2 CO 3 suspension solution can only improve its catalytic activity in the first use. Na 2 CO 3 @EFD catalyst synthesized by impregnating with only Na 2 CO 3 suspension solution owned considerable catalytic activity from nano Na 2 CO 3 (37.0 nm) and good recyclability from nano Fe 3 O 4 (size of 30.0 nm & Ms of 26.77 Am 2 /kg) with biodiesel yield of 99.13 wt% at 65 °C in 2 h with 15/1 methanol/oil molar ratio and 7 wt% catalyst dosage in the first use (93.50 wt% in the eleventh use). The kinetic study with Na 2 CO 3 @EFD was carried out, and it was found that the activation energy was 32.81 kJ/mol and the frequency factor was 3760.85 /min, lower than reported solid base catalysts, which suggested synthesized Na 2 CO 3 @EFD catalyst owned remarkable potential for industrial application in biomass energy conversion.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2021
·Vol. 6
·期 11
·2170-2180
·
IF 4.239
Yueyue He,Huaigang Cheng,Zihe Pan,Fangqin Cheng
The use of ultrasonic process intensification in the preparation of dimethyl carbonate (DMC) by alcoholysis of ethylene carbonate can make up for several disadvantages of heterogeneous catalysis, such as low conversion and long reaction time. In this study, alcoholysis with methanol and ethylene carbonate as raw materials and KF/MgO as a catalyst was enhanced by ultrasonic technology. It was calculated that the theoretical value of the heat of reaction was −19.46 kJ mol−1 and the experimental value was close to 7.15 kJ mol−1. The alcoholysis of ethylene carbonate was an exothermic reaction. An essential finding is that ultrasound can accelerate the reaction rate of alcoholysis of ethylene carbonate and improve the reaction efficiency. When the reaction temperature was 60 °C, the time for the reaction to stabilize was shortened from 50 min to 30 min. When the reaction time was 30 minutes, the conversion of ethylene carbonate under ultrasonic conditions was 79.0%, which was 6.0% higher than the conversion under mechanical stirring. According to the reaction kinetic equation, the activation energy of the alcoholysis of ethylene carbonate was 15.04 kJ mol−1 and the conversion under different reaction conditions was predicted. The catalyst used for the ultrasonic process intensification had obvious pitting on the surface after repeated use. This result may be attributed to the local high temperature, high pressure and the microjet created by the collapse of cavitation bubble cores, which provide a new physical and chemical environment for chemical reactions. The high-speed microjet formed by the collapse of cavitation bubbles repeatedly impacts the surface of the catalyst, causing cavitation erosion on the surface of the catalyst. The fluid shock waves and high-speed microjets formed by the asymmetric collapse of the cavitation bubbles can induce a dispersion effect to make the cavitation field distribution uniform, which can effectively promote the mixing and mass transfer between the KF/MgO catalyst and the reactants, and accelerate the reaction process.
研究领域:
化学工程
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催化科学
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反应动力学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Yu Feng,Huihang Zhang,Deming Zhang,Fuqiang Chen,Xinhai Xu,Jiang Qin,Yi Jiao
The cracking of on-board hydrocarbon fuels is a strong endothermic reaction and can provide an additional chemical heat sink in the cooling process of the hypersonic vehicle. However, the cooling capacity of current hydrocarbon fuels can hardly meet the cooling requirements of the hypersonic vehicle at higher flight speeds. Blending ethanol is an effective method to improve the chemical heat sink of hydrocarbon fuels, but the mechanism of ethanol on chemical heat sink is unclear. In this study, n-decane was selected as a model compound of hydrocarbon fuels to investigate the physical and chemical effect of ethanol on the chemical heat sink of n-decane cracking by analyzing the chemical reactions involved through experimental study and chemical dynamic simulation. The results indicate that there is an optimum ethanol blend ratio to achieve the maximum chemical heat sink. The carbon monoxide methanation reaction which is an exothermic reaction can deteriorate endothermic process at 300–375 °C. With ethanol blending ratio above 20 wt%, ethanol vaporization deteriorates chemical heat sink by reducing the residence time in the temperature range of 225–250 °C. Pressure can suppress the reduction of residence time caused by ethanol evaporation and also suppress the positive reaction of ethanol cracking. The kinetic model of ethanol and n-decane mixture cracking was established. The calculated results verify that ethanol cracking ( C 2 H 5 OH =CO+ C H 4 + H 2 ) and methane cracking ( C H 4 =C+ 2H 2 ) are dominant reactions in ethanol-assisted n-decane thermal cracking below 475 °C.
研究领域:
能源科学
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化学工程
·
航空航天工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 32
·16873-16882
·
IF 14.511
Jianghong Zhao,Rihui Mu,Ya Zhang,Zhidong Yang,Hongxia Zhang,Hu Shi,Min Zhang,Zhanfeng Zheng,Pengju Yang
Polymeric carbon nitride (PCN) semiconductors are appealing light-transducers for photocatalytic redox reactions owing to their unique band gap and stability. However, pristine PCN exhibits moderate efficiency due to the low surface area and serious charge recombination. The delamination of PCN into few-layered nanosheets is an effective strategy to improve the reaction efficiency, but remains a huge challenge. Herein, we report a general approach to prepare few-layered PCN nanosheets by an acetic acid vapor etching strategy. The bulk PCNs obtained from typical precursors including melamine, dicyandiamide, and trithiocyanuric acid can be exfoliated into few-layered nanosheets, while their surfaces can be engineered to present carbon vacancies (CVs). Results confirm that the few-layered nanosheets endow PCN with abundant reactive sites, effective charge separation, and prolonged charge lifetime. Furthermore, experimental and theoretical calculation results verify that the CVs within PCN nanosheets can facilitate electron transfer from the PCN nanosheets to the Pt cocatalyst, significantly lowering the reaction barrier for the formation of H* species. As a result, the PCN nanosheets (with Pt as a cocatalyst) exhibit excellent photocatalytic activity for hydrogen production with visible light. The apparent quantum yield (AQY) for hydrogen production at 400 nm reaches as high as 16.22%, exceeding most of the reported AQY values of PCN-based photocatalysts for hydrogen production. Moreover, it was found that the CVs within PCN nanosheets are favorable for the adsorption and activation of O2 molecules owing to the delocalization of the non-bonding electrons around defects to the absorbed O2, considerably expediting the reaction kinetics of phenol degradation under visible light. This work not only provides a general methodology for the synthesis of few-layered PCN nanosheets but also establishes the connection between the catalyst structure and performance.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Qing Zheng,Nannan Wu,Ruijuan Qu,Gadah Albasher,Wanming Cao,Beibei Li,Nouf Alsultan,Zunyao Wang
4- tert -butylphenol (4-tBP) is a phenolic endocrine disrupting chemical that has attracted great attention due to its wide occurrence, environmental persistence, and possible toxic effects. In this study, we systematically investigated the transformation of 4-tBP in ferrate (VI) oxidation process. The second-order reaction rate constant ( k app ) of Fe(VI) with 4-tBP decreases with solution pH, and the k app value was determined as 295 M −1 ·s −1 at pH 8.0. The removal efficiency of 4-tBP was slightly decreased by Mg 2+ and HCO 3 – , while accelerated at varying degrees by the presence of Cu 2+ and humic acid. Product analysis revealed that 4-tBP was mainly transformed into hydroxylation products, benzene-ring cleavage products, dimers and higher polymerization products via oxygen atom transfer, ring-opening of the benzene ring and radical coupling reaction. Furthermore, initial reactions of 4-tBP were rationalized by theoretical analysis of atom partial charges, frontier electron densities, and spin densities. Nearly complete removal of 4-tBP (20 μM) was achieved after 5 min of reaction in both ultrapure water and natural waters, demonstrating the feasibility of this Fe(VI) oxidation method in treating phenols-contaminated waters.
研究领域:
环境科学
·
化学动力学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Han Wang,Yanli Wang,Quan Ye,Fuchen Ye,Rongkai Kang,Xingchang Zhang,Guowen Chen,Yiqun Du,Jianxin Zhang
Heterostructures facilitate the generation of the interfacial electric field (IEF) that enhances charge transfer and ion diffusion, resulting in improved electrochemical performance in rechargeable aluminum batteries (RABs). However, the ability of heterostructures to generate the IEF is limited, and research efforts on IEF modulation remain scarce, particularly in the field of RABs. Herein, sulfur (S) vacancies are introduced into the core–shell MoS 2 /ZnS heterostructure (Vs-MoS 2 /ZnS) to strengthen the IEF and enhance aluminum storage performance. First-principles computational analyses demonstrate S vacancies increase the work function difference, induce spontaneous interfacial charge transfer, and enhance the IEF. The increased IEF accelerates electron transport, reduces ion diffusion barriers, and increases the adsorption capacity of charge carriers, significantly improving the reaction kinetics of RABs. Moreover, the designed core–shell structure, together with S vacancies, provides strong structural integrity and numerous active sites to the host material. Benefiting from these merits, the Vs-MoS 2 /ZnS cathode demonstrates enhanced reversible capacity (220 mAh g −1 at 0.5 A g −1 ) and long-term cycling stability (127 mAh g −1 over 2000 cycles at 4.0 A g −1 ). This work provides an effective approach for designing heterostructures by modulating the IEF, offering novel insights into the development of advanced RABs cathodes.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Hexuan Li,Dongdong Li,Yilin Li,Haoran Liu,Junzhi Li,Wei Han
The reaction kinetics of lithium-sulfur (Li-S) battery mainly depends on the capture and catalytic conversion efficiency of lithium polysulfide (LiPSs). The unique electron configuration of the 5d metal and the high electrical conductivity of MXene can enhance the interaction between the catalyst and LiPSs. However, the challenge of enhancing the adsorption of LiPSs by regulating the electronic structure of the catalyst with 5d metal and MXene remains unresolved and obscure. In this work, we have developed molybdenum disulfide (MoS 2 )-tungsten disulfide (WS 2 ) @MXene (MoS 2 -WS 2 @MX) heterostructure catalysts for separator coatings in Li-S batteries by introducing W and MXene for the first time. Theoretical calculations demonstrate that the 5 d metallic and conductive MXene coupling effectively modulate the orbital hybridization degree between the catalyst and LiPSs, thereby reducing the energy barrier for LiPSs conversion. Electrochemical test and in situ tests verify the effectiveness of the strategy on the adsorption and conversion of LiPSs. Consequently, the MoS 2 -WS 2 @MX based batteries exhibit high initial reversible capacity of 950.3 mAh g −1 and low capacity decay of 0.066 % per cycle over 500 cycles at 2 C, which is superior to most reported catalysts. This study provides a dual regulatory strategy for enhancing catalytic activity, offering valuable insights for the advancement of high-performance Li-S batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Jing Peng,Yucheng Wu,Ning Long,Wei Shen,Yimin Jiang,Rongxing He,Ming Li
Designing efficient non-precious-metal bifunctional electrocatalysts is still challenging at present. Herein, the efficient Ce,F-Ni 2 P/CoP electrocatalyst for water splitting was successfully fabricated. As shown from the present investigation, the codoping of Ce and F in Ni 2 P/CoP induced the f-p-d gradient orbital coupling in the Ce-F-metal structural unit of the catalyst, significantly reducing the work function of the catalyst, which accelerated the reaction kinetics and improved the intrinsic catalytic activity. The catalyst exhibited the outstanding hydrogen evolution reaction (HER) activity in the full pH range and, especially in alkaline electrolyte, an ultra-low oxygen evolution reaction (OER) overpotential of 243 mV at 50 mA·cm −2 and an excellent HER overpotential of 88 mV at 10 mA·cm −2 were achieved. Moreover, Ce,F-Ni 2 P/CoP displayed an excellent overall water splitting (OWS) performance with η 10 = 1.52 V. DFT theoretical calculations also showed that the gradient orbital coupling resulted in the reduction of the work function of the catalyst. Our work provides a new understanding of designing and constructing high-performance catalysts.
研究领域:
材料科学
·
电化学
✓ 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）