查找使用阿拉丁产品的科研文献

Electrodeposition of Lead from 1-Methylimidazolium Trifluoromethylsulfonate Ionic Liquid

Min Li,Ying Li

In this work, it found that lead oxide (PbO) can be dissolved well in 1-methylimidazolium trifluoromethylsulfonate (MIMTfO) ionic liquid. The electrodeposition of lead from PbO in MIMTfO ionic liquid was studied. Cyclic voltammetry studies showed that the reduction of Pb(II) is a irreversible and one-step reaction process. Chronoamperometry results presented that the nucleation mechanism of lead is fit instantaneous nucleation under diffusion control. The diffusion coefficient of Pb(II) at 373 K is approximately 3.6×10 –8 cm 2 s –1 . The electrodeposition experiments were conducted at 383 K and 393 K using potentiostatic electrolysis. A compact electrodeposit was obtained at 383 K in MIMTfO ionic liquid, which was confirmed to be metallic lead.

Property Improvement of GaAs Surface by 1-Octadecanethiol Passivation

Lu Zhou,Xuefeng Chu,Yaodan Chi,Xiaotian Yang

In this study the effects of 1-Octadecanethiol (ODT, 1-CH3[CH2]17SH) passivation on GaAs (100) surface and GaAs/Al2O3MOS capacitors are investigated. The results measured by X-ray photoelectric spectroscopy (XPS), Raman spectroscopy and scan electron microscopy (SEM) show that the ODT passivation can obviously suppress the formation of As-O bonds and Ga-O bonds on the GaAs surface and produce good surface morphology at the same time, and especially provide better protection against environmental degradation for at least 24 h. The passivation time is optimized by photoluminescence (PL), and the maximum enhancement of PL intensity was 116%. Finally, electrical property of a lower leakage current was measured using the metal-oxide-semiconductor capacitor (MOSCAP) method. The results confirm the effectiveness of ODT passivation on GaAs (100) surface.Keywords:GaAs;passivation;XPS;RAMAN;PL

Convenient synthesis of 1-thiohydroxypyrene by Newman-Kwart rearrangement

Zhang Ran,Xu Lihua,Chen Hui,Qin Zhihong,Zhao Yu,Ni Zhonghai

1-Thiohydroxypyrene( 1 ) and its two intermediates, 1-pyrenyl- O -thiocarbamate( 2 ) and 1-pyrenyl- S -thiocarbamate( 3 ), were synthesized using 1-hydroxypyrene as the starting material. The key synthetic step is Newman-Kwart rearrangement. The results indicate that the Newman-Kwart rearrangement is more effective in suitable solvent than conventional method based on pure organic compound. The structures of compounds 1 – 3 were characterized by FTIR, NMR, GC-MS and elementary analysis. The crystal structures of two new compounds( 2 and 3 ) were determined by single crystal X-ray diffraction analysis. The whole synthetic process is simple, mild and with high yield.

Understanding the reaction kinetics of heterogenous 1-hexene hydroformylation

Zhangxinyu Fan,Muhan Li,Yifan Sun,Weixiang Wang,Qin Zhong,Boyang Liu

Since its discovery by Otto Roelen, hydroformylation has attracted extensive attention for its ability to extend the carbon chain of olefins. Aldehydes, which are converted by the hydroformylation of olefins and syngas (CO/H2), are not only high-value products, but also intermediates to produce fine chemicals, such as alcohols, esters and amines. The currently used homogeneous catalysts bring about the loss of precious metals and the discharge of phosphorus-containing wastes. Therefore, heterogeneous catalysts are developed to simplify the separation process and enhance catalyst recovery. However, the reaction kinetics of heterogeneous hydroformylation, especially the hydroformylation of long-chain olefins, remain unclear. Unlike homogeneous hydroformylation, terminal olefins can be isomerized to internal olefins on heterogeneous catalysts, and can be further converted to different branched aldehydes. Thus, the reaction kinetic of heterogeneous hydroformylation is more complex. In this work, we established a kinetic model for the heterogeneous hydroformylation of long-chain terminal olefins on Rh-based phosphides, using 1-hexene as the model reactant. This kinetic model agrees well with the density functional theory (DFT) results, and can be used to predict the regioselectivity under different reaction conditions. This study reveals the kinetic mechanism of heterogeneous hydroformylation of long-chain terminal olefins, which paves the way for the rational design of heterogeneous catalysts and the theoretical optimization of reaction conditions.

Protocol for assaying irreversible inhibitors of thioredoxin reductase 1

Shibo Sun,Haowen Liu,Wuyang Shi,Hanziyi Zhou,Hao Wu,Weiping Xu,Jianqiang Xu

Summary Selenoprotein thioredoxin reductase 1 (TXNRD1) is a promising therapeutic target, with several inhibitors reported to inhibit TXNRD1 activity. These inhibitors have the potential for applications such as anti-tumor medications. Here, we present a protocol for assessing irreversible inhibitors of TXNRD1. We describe four assays covering cellular TXNRD activity measurement, recombinant enzyme-based activity determination, differential scanning fluorimetry (DSF), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. This protocol will facilitate the screening and development of potential small-molecule inhibitors of TXNRD1.

1-Naphthylamine thioxanthone-based one-component visible-light photoinitiators

Le Ma,Yang Hou,Jun Nie,Xiaoqun Zhu

The introduction of substituents affects the planarity of the molecule, resulting in different physical and chemical properties. This study synthesized four one-component visible light photoinitiators with different substituents derived from 1-naphthylamine. They were amine-free (BTX), primary amine (BTX-A), secondary amine (BTX-MA), and tertiary amine (BTX-DMA). The photophysical and photochemical properties were explored using UV–visible absorption spectroscopy combined with DFT theory computational simulations. They had excellent absorption properties in the visible light range ( ε : 3200–6300 L mol −1  cm −1 ). The structure of amine substitutions in the initiators showed different redshift phenomena. The maximum absorption wavelength of BTX in the visible region is 388 nm; only a 7 nm red shift occurred for the maximum absorption wavelength of BTX-DMA. While BTX-A had a maximum absorption wavelength of red shifting by 41 nm， the red shift for BTX-MA was about 53 nm, and its UV absorption tail extended to 520 nm. This phenomenon was known to be the result of the combined effect of electronic donor and molecular planarity according to the DFT theoretical calculations. The photopolymerization kinetics of four initiators used for double bond monomers was investigated by real-time FT-IR. The results indicated that polymerization could occur for all the designed systems; the highest double bond conversion could reach 92 % when BTX-DMA was used as a visible-light photoinitiator for the monomer of 2-hydroxyethyl acrylate (HEA).

Chemistry of catalytic cracking of cyclohexene and 1-methylcyclopentene

Xueqian Zhang,Jiasong Yan,Shuai Yuan,Shanqing Yu,Qingyu Liu,Xikai Wang,Rui Li

Whether cycloalkanes undergo six- or five-membered ring-opening reaction pathways remains controversial. In this work, the catalytic cracking reactions of cyclohexene and 1-methylcyclopentene, as model compounds, were investigated in a pulse microreactor. The characteristics of the reactions of the two model compounds were compared in terms of isomerization, cracking, and hydrogen transfer reaction, and the reasons for the differences in their catalytic reactions were analyzed in combination with thermodynamic and molecular simulation calculations. The results have shown that the catalytic cracking product distributions of cyclohexene and 1-methylcyclopentene were similar owing to their easy mutual isomerization; the five-membered ring-opening cracking pathway was more thermodynamically advantageous than that of six-membered ring-opening cracking, and therefore, the yield of the ring-opening cracking product of 1-methylcyclopentene was comparatively higher; the main products of the hydrogen transfer reaction of the two compounds were alkanes and aromatic hydrocarbons. By comparing the product distributions and reaction activation energies, the ring-opening reaction pathways were clarified, and the catalytic cracking reaction networks of cyclohexene and 1-methylcyclopentene were established.

Synthesis of 2-Amino-1-indanone from DL-Phenylalanine

Rong Zhao,Peijiang Guo,Junyu Dong,Xiaoping Zhang,Xiaofei Sun,Yun Tian,Qingle Zeng

Kinetics of atmospheric reactions of 4-chloro-1-butene

Zhu Jianqiang,Tsona Narcisse T.,Du Lin

Chloroalkenes are among the important anthropogenic organic compounds emitted in the atmosphere as a result of their wide use in synthetic processes in industry. Despite their well-known adverse effects on human health and air quality, the chemistry of these chloroalkenes remains poorly explored. In this work, reactions of 4-chloro-1-butene (CBE), a representative example of chloroalkenes, with O 3 , OH, NO 3 , and Cl are investigated in a 100-L Teflon reaction chamber equipped with gas chromatography-flame ionization detector (GC-FID). The absolute rate method was used for the reaction with O 3 while the relative rate method was used for reactions with OH, NO 3 , and Cl. The following rate constants were obtained at room temperature (298 ± 2) K and atmospheric pressure: (3.96 ± 0.43) × 10 −18 , (2.63 ± 0.96) × 10 −11 , (4.48 ± 1.23) × 10 −15 , and (2.35 ± 0.90) × 10 −10  cm 3 molecule −1  s −1 , for reactions with O 3 , OH, NO 3 , and Cl, respectively. Atmospheric lifetimes of CBE calculated from rate constants of the different reactions obtained in this work showed that reaction with OH is the main loss process for CBE, while in coastal areas and in the marine boundary layer, the CBE loss by Cl reaction becomes important. Estimation of the value of the photochemical ozone creation potential (POCP) indicated that CBE has a large ozone formation potential. The present work underlines the need for further studies on the atmospheric chemistry of chlorinated VOCs.

Excellent humidity sensor based on ultrathin HKUST-1 nanosheets

Qiaoe Wang,Meiling Lian,Xiaowen Zhu,Xu Chen

The copper-based MOF, HKUST-1 has been applied for humidity sensing owing to hydrophilic ligands and open metal sites which are suitable for sensitively detecting moisture. However, most of the research on the sensor HKUST-1 focuses on the role of the central metal. There are few reports on the morphology–activity relationship of HKUST-1. In this work, we synthesized two kinds of HKUST-1 including octahedral structures and ultrathin nanosheets, and systematically studied the performance of moisture sensing. Compared to HKUST-1 octahedra, HKUST-1 nanosheets showed lower and wider detectable humidity range, achieving a fast response. Starting from the exposed hydrophilic functional groups of HKUST-1 nanosheets, we have revealed that hydrophilic ligands play an important role in improving the adsorption capacity during the adsorption process. In addition, ultra-thin HKUST-1 nanosheets act as an excellent mass transfer medium, accelerating proton transfer and water molecule movement. To further improve the performance of the HKUST-1 humidity sensor, black phosphorus quantum dots (BPQDs) with a high surface reactivity were used to build a composite sensing platform. The excellent proton transfer capability of BPQDs leads to one order of magnitude improvement in the sensitivity of the BPQDs/HKUST-1 systems compared to HKUST-1 only.

Solid-liquid equilibrium of 1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethenone in twelve mono-solvents: Solubility determination, Hansen solubility parameter and thermodynamic analysis

Pengshuai Zhang,Ruping Ge,Chunxia Jin,Jixiu Deng,Feiyang Dai,Yameng Wan,Beibei Zhang,Shuwei Yu,Xing Li,En Zhang,Lan Zhang,Lu Zhang

The mole fraction solubility of 1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethenone (1-HPE) in twelve mono-solvent systems namely “2-methoxyethanol (2-ME), methanol (MeOH), ethanol (EtOH), butan-1-ol ( n -BuOH), 2-propoxyethanol (2-PE), propan-2-ol ( i -PrOH), 2-methylpropan-1-ol ( i -BuOH), Acetonitrile (MeCN), ethane-1,2-diol (EG), 2-ethoxyethanol (2-EE), propan-1-ol ( n -PrOH), 2-butoxyethanol (2-BE)” were determined from 283.15 K to 323.15 K under 0.1 MPa. The experimental solubility order follows: 2-ME > 2-EE > 2-PE > 2-BE > MeOH > EtOH >  n -PrOH >  i -PrOH ≈  n -BuOH >  i -BuOH ≈ MeCN > EG. The UNIQUAC model, modified Apelblat model, NRTL model, Wilson model, Jouyban model and NRTL-SAC model equation were used to correlate of 1-HPE solubility, and the average 10 4 RMSD of them was 0.89, 1.21, 0.94, 4.72, 0.60 and 1.25, respectively. Furthermore, Hansen solubility parameters analysis (HSP) was used to evaluate the miscibility of 1-HPE in the selected solvents. Hirshfeld surface (HS) analysis was performed to discuss the electrostatic features and the patterns of intermolecular interactions of 1-HPE. Thermodynamic properties (Δ mix G , Δ mix S , Δ mix H , Δ dis G , Δ dis S , Δ dis H ) were calculated by the UNIQUAC model. The calculated results indicated that the dissolution and mixing process of 1-HPE in the mono-solvents selected in this work was spontaneous and entropy increment.

Controlled Formation of Pyrazines: Inhibition by Ellagic Acid Interaction with N-(1-Deoxy-d-xylulos-1-yl)-glycine and Promotion through Ellagic Acid Oxidation

Ziyan Wang,Heping Cui,Mengyu Ma,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho

The effect of ellagic acid on the formation of pyrazine, methylpyrazine, 2,3-methylpyrazine, 2,6-methylpyrazine, 2,5-methylpyrazine, and trimethylpyrazine in the xylose–glycine Maillard reaction model was researched. Ellagic acid could either inhibit or promote pyrazine formation, depending on its addition time point and the pH of the system. The addition of ellagic acid during the accumulation period of an Amadori compound inhibited pyrazine formation by capturing the Amadori compound in the xylose–glycine Maillard system and decreasing the pyrazine precursors. The inhibitory effect of ellagic acid on pyrazine formation got more obvious with an increase in the pH of the system. However, when ellagic acid was added at the beginning of the xylose and glycine Maillard system and when the oxidizing substances such as glyoxal and methylglyoxal were significantly formed in the Maillard system, its oxidation could promote the formation of pyrazines.