INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Xiaohan Li,Yanglong Zhou,Ying Bao,Wei Wei,Xiaoma Fei,Xiaojie Li,Xiaoya Liu
Development of a new packaging material with superior high-temperature stability is becoming increasingly crucial in high-power and high-density electronics industry. In this study, we employed bis(3-ethyl-5-methyl-4-maleimidephenyl)methane (BMI), para-xylene phenolic resin (PF), and triphenylmethane novolac epoxy resin (EP) as matrix resins to develop high-temperature-stable BPE ternary resin molding compounds for power device packaging. BMI was first melt-blended with PF to obtain the premix with a reduced softening point for meeting the requirement of melt-kneading process. 2-Ethyl-4-methylimidazole with a dosage of 2 wt % of the ternary resins, could effectively promote the curing reaction, making the molding process of BPE molding compounds be compatible with that of the existing epoxy molding compounds (EMC). The introduction of BMI component could enhance the chain rigidity and heat resistance of cured resins. When the BMI content was more than 70 wt % of the ternary resins, the cured BPE molding compounds exhibited the glass transition temperature and initial decomposing temperature larger than 250 and 400 °C, respectively, indicating a much superior thermal performance to that of the cured EMC. Moreover, the flexural performance and the adhesion strength with copper at 260 °C, high-temperature aging resistance, dielectric properties, and thermal conductivity of the cured BPE molding compounds were also improved compared with those of the cured EMC. This study provides a promising strategy for preparing heat-resistant electronic packaging molding compounds.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Zahid Nawaz,Nevin Gürbüz,Muhammad Naveed Zafar,Muhammad Nawaz Tahir,İsmail Özdemir,Ryan J. Trovitch
A mild catalytic protocol for aldehyde, amine, and alkyne coupling (A 3 -coupling) allows for the selective synthesis of propargyl amines using 5,6-dimethylbenzimidazole-derived N-heterocyclic carbene (BNHC) silver(I) catalysts. A series of BNHC Ag(Ⅰ) halide complexes were synthesized and their structures have been elucidated through the use of multinuclear NMR and FT-IR spectroscopy. Furthermore, the pseudo-linear geometry of two different compounds was substantiated by single-crystal X-ray diffraction. Silver-based A 3 -coupling was achieved for both acyclic and cyclic secondary amines using a diverse set of alkynes to afford propargyl amines with yields of up to 95 %. The present approach is environmentally benign and water is generated as the sole byproduct.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2019
·
IF 4.978
Huai Liu,Xuejuan Cao,Ting Wang,Junnan Wei,Xing Tang,Xianhai Zeng,Yong Sun,Tingzhou Lei,Shijie Liu,Lu Lin
The conversion of concentrated 5-hydroxymethylfurfural (HMF) or fructose to 2,5-furandicarboxylic acid (FDCA), a renewable alternative to petroleum-derived terephthalate acid, is highly desirable but challenging for FDCA production in an industrial scale. In this contribution, DMSO/H 2 O mixture was demonstrated as an effective medium for the production of FDCA from high concentration of HMF or fructose. For example, FDCA yield up to 93% was achieved at 10 wt% HMF concentration in DMSO/H 2 O over commercially available Ru/C (2 equiv. NaHCO 3 , 130 °C, 4 MPa O 2 and 12 h). Furthermore, an overall FDCA yield of 65% was achieved from concentrated fructose (19 wt%) through a facile two-step process. Notably, it is so far the highest HMF or fructose concentration employed for FDCA formation. As compared to pure water or DMSO , DMSO/H 2 O mixed system is able to stabilize HMF in an alkaline environment, which allows the efficient oxidation of HMF at high concentrations.
研究领域:
生物化学
·
可再生化学
·
绿色化学
✓ 已验证
DOI
高影响因子
ANALYTICAL BIOCHEMISTRY
·
2015
·
IF 2.219
Chunxiang Zhang,Guangyu Shen,Youming Shen,Xiangyang Zhang
In this work, a novel thiol aromatic aldehyde was synthesized. It can be used as a substrate to directly immobilize antibodies on a gold electrode, for which no additional chemical cross-linker is required. It was also applied as a linker to prepare Fe 3 O 4 @Au/PAMAM/Ab 2 –horseradish peroxidase bioconjugates , which introduced multiple enzymes onto a sensing interface owing to the high surface-to-volume ratio of Fe 3 O 4 @Au nanoparticles and many functional groups of the poly(amidoamine) dendrimer (PAMAM). The introduced multiple enzymes greatly improved the detection signal. Under optimal conditions, the proposed electrochemical immunosensor exhibited desirable performance for detection of IgG in the range 0.005–50 ng ml −1 with a detection limit of 3 pg ml −1 based on a signal-to-noise ratio of 3. It has great potential application in the area of clinical analysis.
研究领域:
生物医学工程
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分析化学
·
纳米技术
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2024
·Vol. 154
·期 7
·3818-3828
·
IF 2.3
Zhou Ruoyu,Lei Qian,Deng Conger,Liang Linlin,Chen Honglin
Formaldehyde-water-trioxane (HCHO–H 2 O–TOX) tends to form a stable azeotrope and the HCHO solution can also produce multiple by-products, making it challenging to refine and obtain high-purity TOX, resulting in increased energy consumption. Formic acid (FA) is the most easily generated and undesirable main byproduct of HCHO, which has strong corrosiveness to production equipment. However, the negative impact of HCHO mentioned above is often overlooked because of its low concentration. In this study, the CuO/ZnO–AlN catalyst was synthesized using a simple deposition precipitation method. The catalyst demonstrated a high removal rate of HCHO and inhibition of FA, along with excellent hydrothermal stability. Aluminum nitride (AlN) can form a layer of Al(OH) 3 coating, acting as a physical barrier against H 2 O during the reaction process and releasing trace OH − to facilitate the formation of Cannizaro intermediates. It can then catalyze HCHO dehydrogenation under alkaline-free conditions to form H 2 and an intermediate (HCOO − ), which is further converted to H 2 and CO 2 under the influence of Cu 0 . The relevant characterization results showed that Cu 0 is the active site. The strong interaction between AlN and copper refines the particle size of CuO and promotes the reduction of CuO to Cu 0 . In addition, an H 2 atmosphere can more effectively inhibit the oxidation of Cu 0 compared to an N 2 atmosphere, resulting in a higher HCHO removal rate. This rate can reach 100% at 105 ℃ and 4 MPa H 2 and almost no FA can be detected in the product. Cycling tests proved that the prepared catalyst could be recycled and reused three times without a noticeable reduction in catalytic activity, demonstrating its good application potential. Graphical Abstract
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2024
·
IF 2.5
Fumeng Yin,Shan Hu,Shuwei Zhu,Shifeng Xing,Hongjun Zhu
Graphical Using mesoporous graphitic carbon nitride (mpg-C 3 N 4 ) as a metal-free heterogeneous photocatalyst was developed for thiocyanation of alkenes under visible light irradiation with oxygen as green oxidant and without any other additives. The present protocol has excellent functional group tolerance and the desired tetrasubstituted alkenyl thiocyanides were obtained in moderate to good yields. Moreover, the recyclable mpg-C 3 N 4 catalyst could be used at least 6 times without significant loss of activities. Using mesoporous graphite carbon nitride (mpg-C 3 N 4 ) as metal-free heterogeneous catalyst, the thiocyanation of ketene dithioacetals was achieved under visible light irradiation with oxygen as green oxidant and without any other additives. The present protocol has excellent functional group tolerance and the desired tetrasubstituted alkenyl thiocyanides were obtained in moderate to good yields. Moreover, the recyclable mpg-C 3 N 4 catalyst could be used at least 6 times without significant loss of activities. A series of mechanistic validation experiments indicated that the reaction involves a radical process.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Yunfei Chang,Yuze Li,Chen Zhang,Tongyao Zhao,Xiaohang Tuo,Jing Guo,Yumei Gong
We developed a facile one-pot method to synthesize multishelled hollow mesoporous SiO2 microspheres (HMSs) with controllable interior structures including one-shell, double-shell, and yolk–shell. Single reagent formaldehyde could fully control the morphology of HMSs, in that formaldehyde was crucial to the SiO2 precursor’s hydrolysis rate and the template pore size.
研究领域:
材料科学
·
纳米医学
·
药物递送
·
生物材料
·
纳米技术
✓ 已验证
DOI
高影响因子
Advanced Materials Interfaces
·
2019
·Vol. 7
·期 2
·1901703
·
IF 4.713
Weicai Zhang,Jing Peng,Mingtao Zheng,Hanwu Dong,Hang Hu,Yong Xiao,Yingliang Liu,Yeru Liang
Assembling of well-orientated mesopores and 0D substance into an orchestrate architecture for constructing advanced carbon-based composites is highly attractive. Currently, this nanofabrication method is facing challenges, because of the difficulty in the co-assembly of the building blocks is very hard to perform onto a high-curvature and heterogeneous 0D substrate. Here, an efficient active nanointerface-assisted co-assembly approach for design and fabrication of a novel class of yolk–shell Au@ordered mesoporous carbon nanosphere is reported. The key point to this preparation strategy is construction of reactive aldehyde functional groups on the surface of Au@SiO 2 nanospheres, which can react with the carbon source to in situ form a stable covalent bond at their nanointerface. The as-synthesized yolk–shell Au@ordered mesoporous carbon nanosphere not only exhibits uniform spherical morphology and robust porosity but also possesses a totally new ordered mesoporous and fast permeable shell structure, providing a chance for greatly broadening their application scope.
研究领域:
材料科学
·
纳米医学
·
生物材料
·
药物递送
·
肿瘤治疗
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Shuo Wang,Yanyan Li,Fanteng Ma,Xiaozhong Wu,Pengfei Zhou,Zhichao Miao,Peibo Gao,Shuping Zhuo,Jin Zhou
Potassium ion batteries (PIBs) have received widespread attention nearly four years due to sufficient potassium resources and similar chemical properties of potassium to lithium. Several works reported that N-doping on the carbon electrodes could efficiently improve the storage capacity of potassium ions. Herein, we synthesized two series of carbon spheres with the main difference is with or without N-doping. It is found that the storage of potassium ions is mainly determined by the crystal structure instead of N-doping. N-doping seems to affect the ion diffusion process, but the total capacity is still determined by the (0 0 2) lateral size of the carbon materials ( L a ). The specific capacity increases as L a increases. The N-doped carbon sphere with larger L a of 8.32 nm, delivers a higher reversible capacity of 241 mAh g −1 at a current density of 25 mA g −1 . And it still remains 121 mAh g −1 after 100 cycles at a current density of 100 mA g −1 .
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
碳材料
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 4
·956-964
·
IF 2.936
Han Song,Chen Wen-Ting,Gao Zi-Teng,Guan Hua,Li Zhang-Min,Tao Duan-Jian
A mechanochemical treatment and subsequent high temperature annealing strategy was developed for the synthesis of nitrogen-doped carbon supported cobalt catalysts. The as-prepared Co/NC 800 catalyst was demonstrated for efficient and selective hydrogenation of furfural into furfuryl-based alcohols and amines with good to excellent yields under optimum conditions. Graphical
研究领域:
催化
·
材料科学
·
有机化学
·
化学合成
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2016
·
IF 3.958
Lei Zhao,Baoyue Zhang,Xin Xiao,Feng Long Gu,Rui-Qin Zhang
Active species such as holes, electrons, hydroxyl radicals ( OH), and superoxide radical anions ( O 2 − ) involved in the photocatalytic oxidation of benzyl alcohol (BA) into benzaldehyde (BAD) on TiO 2 under ultraviolet (UV) light were investigated by adding corresponding scavengers. The experimental results show that the oxidation of BA into BAD is driven mainly by the holes and OH radical. The role of dissolved O 2 was studied by bubbling N 2 through the reaction. The results show that the dissolved O 2 is, to some extent, the source of OH. Additional density functional theory (DFT) calculations identified two H-abstraction pathways ( R abs OH and R abs α). The structure of the R abs OH product is less stable and tends to transfer resulting in the R abs α product. The holes are the main driving force for the abstracting of H from BA. The OH radical combines with the H-abstract product to form a precursor of product BAD, detected by LC–MS technique ( m / z 123), which then undergoes an intramolecular dehydration reaction to form BAD. The results will help to select the optimal active species for the photocatalytic oxidation of BA into BAD on TiO 2 under UV light.
研究领域:
物理化学
·
光催化
·
环境化学
·
材料化学
·
理论计算化学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Xiaodong Wang,Lili Ye,Xiaoyuan Zhang,Zhihe Zhang,Jiuzhong Yang,Long Zhao
Acetaldehyde, ethylene oxide , and vinyl alcohol are three C 2 H 4 O isomers that are ubiquitous in combustion over a wide temperature range. A comprehensive reaction kinetics study has been performed for reactions that occur on the same C 2 H 4 O potential energy surface , mainly including the unimolecular reactions of three C 2 H 4 O isomers and the recombination reaction of CH 3 with HCO. Temperature- and pressure-dependent rate coefficients were updated or newly predicted by performing quantum chemical calculations coupled with RRKM/master equation simulations. The dominance of C C bond fission is reconfirmed for acetaldehyde decomposition at higher temperatures. The negligible contribution of CH 4 + CO channel from usual tight intramolecular H-shift transition state provides indirect evidence for previously reported roaming mechanism that was proposed to explain the observation of CH 4 + CO in acetaldehyde pyrolysis . For ethylene oxide pyrolysis , current experiment and kinetic prediction have a good consistency in branching ratios between the formation of acetaldehyde and vinyl alcohol products. The radicals of CH 3 + HCO can also be directly generated from ethylene oxide through a well-skipping reaction mechanism especially at higher temperatures. For CH 3 + HCO recombination, we highlight the importance of CH 3 CO + H channel that was often overlooked previously. Kinetic simulations show that the incorporation of updated rate coefficients and newly identified channels results in a measurable influence on C2 chemistry , indicating the possibility and necessity of further improvement of core mechanism in combustion kinetic models .
研究领域:
物理化学
·
燃烧化学
·
反应动力学
·
量子化学计算
·
分子反应机制
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）