两亲聚离子液体-钒掺杂杂多酸离子复合体催化的苯氧化羟化

以N,N-二甲基烯丙基胺、1-氯乙酸、Well-Dawson构型H_(7)[P_(2)Mo_(17)VO_(62)]、,H_(8)[P_(2)Mo_(16)V_(2)O_(62)],、H_(9)[P_(2)Mo_(15)V_(3)O_(62)]为起始原料,经季铵化、自由基聚合、分子自组装构建了三种两亲聚离子液体-钒掺杂杂多酸离子复合体PPIL-1~3,离子复合体集两亲活性、氧化催化活性和多孔性与一体,以其为非均相催化剂,工业级30%过氧化氢为氧化剂,在温和反应条件下,实现了苯一步氧化羟化制备苯酚。当离子复合体用量为0.1g,苯10mmol,过氧化氢20mmol,以15mL乙腈为溶剂,反应温度60℃,反应时间4h,苯酚产率37.3%。离子复合体经离心分离、溶剂洗涤、真空干燥即可再生循环使用,循环使用6次,催化活性基本保持不变。

相转移催化氧化酮羟化反应合成两种甾体药物

以含有17(20)甾体烯烃(1a和2a)为研究对象,对比考察了不同氧化体系以及含有过氧硫酸盐的均相和非均相溶液体系的氧化效果,设计了一种n-Bu4NHSO4/CH2Cl2/H2O相转移催化RuCl3/Oxone氧化酮羟化反应体系,制备得到17α-羟孕酮(1)和醋酸去氧皮质酮(2)两种甾体药物,收率分别达到69%和60%。该双相溶剂体系避免了水和酸性离子对反应的影响,具有步骤简单,副产物少的特点,适用于甾体激素药物α-羟基酮侧链的引入和合成。

贲门癌组织微粒体环氧化物羟化酶基因多态变化

目的 :探讨贲门癌组织微粒体环氧化物羟化酶 (mEH)基因多态性改变 ,进一步深入了解贲门癌高易感性分子基础。方法 :利用PCR和PCR SSCP方法对 19例贲门腺癌和 72例正常对照组织mEH基因多态性进行了检测。结果 :贲门腺癌和正常对照组织中 ,mEH的Arg/His和His/His基因型合并在一起分别占 16 %和 15 % ,His等位基因对贲门癌易感性并无明显影响 (OR =0 .72 ) ;mEH的His/Tyr和Tyr/Tyr基因型合并在一起分别占 5 8%和 5 7% ,Tyr等位基因并未影响个体对贲门癌的易感性 (OR =0 .92 )。结论 :mEH基因多态对贲门癌易感性无明显影响。

稻瘟菌侵染诱导的水稻过氧羟基脂肪酸羟化环氧化酶的抗血清制备

通过选择性抽提、盐析、阴阳离子交换柱层析等步骤从非亲和性稻瘟菌侵染的 12 0 g稻叶中获得了诱导性过氧羟基脂肪酸羟化环氧化酶 ( POG)的电泳纯蛋白 2 50 μg。利用这些纯化蛋白 ,制备了POG的抗血清。点免疫杂交结果表明 ,该抗血清效价大于 1:50 0 0 ,其抗原检测灵敏度可达 0 .0 5ng,并具有较好的特异性。蛋白印迹结果显示 ,稻瘟菌侵染可诱导

Realizing efficient electrochemical oxidation of 5-hydroxymethylfurfural on a freestanding Ni(OH)_(2)/nickel foam catalyst

With the continuous improvement of solar energy production capacity,how to effectively use the electricity generated by renewable solar energy for electrochemical conversion of biomass is a hot topic.Electrochemical conversion of 5-hydroxymethylfurfural(HMF)to biofuels and value-added oxygenated commodity chemicals provides a promising and alternative pathway to convert re-newable electricity into chemicals.Although nickel-based eletrocatalysts are well-known for HMF oxidation,their relatively low intrinsic activity,poor conductivity and stability still limit the poten-tial applications.Here,we report the fabrication of a freestanding nickel-based electrode,in which Ni(OH)_(2) species were in-situ constructed on Ni foam(NF)support using a facile ac-id-corrosion-induced strategy.The Ni(OH)2/NF electrocatalyst exhibits stable and efficient electro-chemical HMF oxidation into 2,5-furandicarboxylic acid(FDCA)with HMF conversion close to 100% with high Faraday efficiency.In-situ formation strategy results in a compact interface between Ni(OH)_(2) and NF,which contributes to good conductivity and stability during electrochemical reac-tions.The superior performance benefits from dynamic cyclic evolution of Ni(OH)_(2) to NiOOH,which acts as the reactive species for HMF oxidation to FDCA.A scaled-up device based on a continu-ous-flow electrolytic cell was also established,giving stable operation with a high FDCA production rate of 27 mg h^(-1)cm^(−2).This job offers a straightforward,economical,and scalable design strategy to design efficient and durable catalysts for electrochemical conversion of valuable chemicals.

Selective oxidative dehydrogenation of ethane to ethylene over a hydroxylated boron nitride catalyst

Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane conversion of 11%.Even at high conversion level of 63%,the selectivity of ethylene retained at 80%,which is competitive with the energy-demanding industrialized steam cracking route.A long-term test for 200 h resulted in stable conversion and product selectivity,showing the excellent catalytic stability.Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.

药物超敏反应综合征的研究进展

药物超敏反应综合征(drug-induced hypersensitivity syndrome,DHS)为严重的药物反应类型之一,其临床表现为突然发生的泛发性皮肤损害,伴发热、淋巴结肿大、血液学异常(嗜酸性粒细胞增多)以及多脏器受损,主要诱发超敏反应的药物为芳香族类的抗癫痫药和磺胺类药物。该病的死亡率达10%～20%,其发生机制尚不清楚,可能涉及敏感药物代谢途径异常、疱疹病毒感染与再激活、个体遗传易感性等众多因素。阐明DHS发生的可能机制将对揭示该病征的本质、提高疾病风险预测以及指导临床安全用药具有重要意义。

Theoretical Study on Impact of Single Water Molecule on OH＋O3 Reaction

Quantum chemical calculations are performed to study the reactions of OH and ozone with- out and with water to estimate whether the single water molecule can decrease the energy barrier of the OH radical reaction with ozone. The calculated results demonstrate that the single water molecule can reduce the activated barrier of the naked OH＋Oa reaction with the value of about 4.18 kJ/mol. In addition, the transition state theory is carried out to determine whether the single water molecule could enhance the rate constant of the OH＋O3 reaction. The computed kinetic data indicate that the rate of the ozone reaction with the formed complexes between OH and water is much slower than that of the OH＋O3 reaction, whereas the rate constant of OH reaction with the formed H20---Oa complex is 2 times greater than that of the naked OH radical with ozone reaction. However, these processes in the atmosphere are not important because the reactions can not compete well with the naked reaction of OH with ozone under atmospheric condition.

Copper‐doped nickel oxyhydroxide for efficient electrocatalytic ethanol oxidation

Rational design of low‐cost and efficient electrocatalysts for ethanol oxidation reaction(EOR)is imperative for electrocatalytic ethanol fuel cells.In this work,we developed a copper‐doped nickel oxyhydroxide(Cu‐doped NiOOH)catalyst via in situ electrochemical reconstruction of a NiCu alloy.The introduction of Cu dopants increases the specific surface area and more defect sites,as well as forms high‐valence Ni sites.The Cu‐doped NiOOH electrocatalyst exhibited an excellent EOR performance with a peak current density of 227 mA·cm^(–2)at 1.72 V versus reversible hydrogen electrode,high Faradic efficiencies for acetate production(>98%),and excellent electrochemical stability.Our work suggests an attractive route of designing non‐noble metal based electrocatalysts for ethanol oxidation.

Oxidation of glycerol with H_2O_2 on Pb-promoted Pd/γ-Al_2O_3 catalysts

A series of bimetallic Pd-Pb catalysts with a constant Pd content of 1 wt%and Pb/Pd atomic ratio from 0 to 1.6 supported on γ-Al2O3 were prepared and used for glycerol oxidation with H2O2 as the oxidizing agent at atmospheric pressure,45℃ and pH =11.The morphology and dispersion of the catalysts were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy（SEM-EDX） and transmission electron microscopy（TEM）.The presence of an alloy phase in the bimetallic catalyst was detected by X-ray photoelectron spectroscopy（XPS）.Glycerol conversion obtained with the monometallic Pd catalyst was 19%,which was increased to 100%with the addition of Pb.The four bimetallic PdPb catalysts were able to oxidize glycerol to dihydroxyacetone（DIHA） and the selectivity to DIHA reached 59%,58%,34%and 25%for PdPb0.25,PdPb0.50,PdPb1.00 and PdPbl.60 catalysts,respectively.

Mesoporous polyoxometalate-based ionic hybrid as a highly effective heterogeneous catalyst for direct hydroxylation of benzene to phenol

Self‐assembled mesoporous polyoxometalate‐based ionic hybrid catalyst,[PxyDim]2.5PMoV2,was prepared by combining p‐xylene‐tethered diimidazole ionic liquid[PxyDim]Cl2with Keggin‐structured V‐substituted polyoxometalate H5PMo10V2O40.The obtained hybrid was shown to be a mesostructured and hydrophobic material with good thermal stability.In the H2O2‐based hydroxylation of benzene to phenol,the hybrid showed extraordinary catalytic activity and rate,and quite stable reusability.The unique hydrophobic properties and mesoporous structure of the hybrid were responsible for its excellent catalytic performance.

A “Green” Cyclohexanone Oxidation Route Catalyzed by Hollow Titanium Silicate Zeolite for Preparing ε-Caprolactone,6-Hydroxyhexanoic Acid and Adipic Acid

Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical methods, such as XRF, XRD, low-temperature N2 adsorption/desorption, TEM, FT-IR, UV-Vis, 29Si MAS NIVIR, and XPS techniques. The characterization results suggest that HTS zeolite has a special hollow crystal structure and its mesopore volume is larger than that of TS-1 zeolite. The titanium species in this zeolite are composed of the framework tetrahedral Ti （IV） ions and extra-framework octahedral Ti （IV） ions, which tend to disperse into its bulk phase. This zeolite material also has been applied to catalyze the cyclohexanone oxidation process, and the products are not completely consistent with those results obtained by using TS-1 zeolite, which might be caused by their difference in pore structure and pore volume, especially the mesopore volume. Cy- clohexanone oxidation catalyzed by HTS zeolite is a representative consecutive reaction, the main target products of which are e-caprolactone, 6-hydroxyhexanoic acid and adipic acid. The effect of H202/cyclohexanone mole ratio on the cyclohexa- none conversion, the total target product selectivity, the distribution of three target products selectivity and their variations along with reaction time is also researched and analyzed, which indicate that HTS zeolite shows a high performance for the Baeyer-Villiger reaction of cyclohexanone and catalytic oxidation of 6-hydroxyhexanoic acid under mild conditions, and the quantity of active surface titanium species as well as the pore structure and mesopore volume controlling the mass diffusion rate are the key factors determining the catalytic activity of HTS zeolite and product selectivity.

Highly efficient Nb2O5 catalyst for aldol condensation of biomass-derived carbonyl molecules to fuel precursors

Aldol condensation is of significant importance for the production of fuel precursors from biomass- derived chemicals and has received increasing attention. Here we report a Nb2O5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb2O5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO2 and Al2O3), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium- aluminum hydrotalcite). The detailed characterizations by N2 sorption/desorption, NH3-TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb2O5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb2O5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb2O5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation.

Oxidation of 2,5‐bis(hydroxymethyl)furan to 2,5‐furandicarboxylic acid catalyzed by carbon nanotube‐supported Pd catalysts

The selective oxidation of 2,5‐bis(hydroxymethyl)furan(BHMF)in this work was proven as a promising route to produce 2,5‐furandicarboxylic acid(FDCA),an emerging bio‐based building‐block with wide application.Under ambient pressure,the modified carbon nanotube‐supported Pd‐based catalysts demonstrate the maximum FDCA yield of 93.0%with a full conversion of BHMF after 60 min at 60°C,much superior to that of the traditional route using 5‐hydroxymethylfurfural(HMF)as substrates(only a yield of 35.7%).The participation of PdH_(x) active species with metallic Pd can be responsible for the encouraging performance.Meanwhile,a possible reaction pathway proceeding through 2,5‐diformylfuran(DFF)and 5‐formyl‐2‐furancarboxylic acid(FFCA)as process intermediates is suggested for BHMF route.The present work may provide new opportunities to synthesize other high value‐added oxygenates by using BHMF as an alternative feedstock.

Highly selective production of phenol from benzene over mesoporous silica-supported chromium catalyst:Role of response surface methodology in optimization of operating variables

A Cr/SBA-16 catalyst was prepared using Cr（NO3）3 as a precursor and mesoporous silica SBA-16 as a support via a simple impregnation method. The catalyst was characterized using wide-angle X-ray diffraction （XRD）, low-angle XRD, N2 adsorption-desorption, transmission electron microscopy, and ultraviolet-visible spectroscopy. The catalyst activity was investigated in the direct bydroxylation of benzene to phenol using H2O2 as the oxidant. Various operating variables, namely reaction temperature, reaction time, amount of H2O2, and catalyst dosage, were optimized using central composite design combined with response surface methodology （RSM）. The results showed that the correla- tion between the independent parameters and phenol yield was represented by a second-order polynomial model. The high correlation coefficient （R2）, i.e., 0.985, showed that the data predicted using RSM were in good agreement with the experimental results. The optimization results also showed that high selectivity for phenol was achieved at the optimized values of the operating variables： reaction temperature 324 K, reaction time 8 h, H2O2 content 3.28 mL, and catalyst dosage 0.09 g. This study showed that RSM was a reliable method for optimizing process variables for benzene hydroxylation to phenol.

An Improvement on Si-etching Tetramethyl Ammonium Hydroxide Solution

An optimal concentration of the etching solution for deep etching of silicon, including 3% tetramethyl ammonium hydroxide and 0.3% (NH4)2S2O8, was achieved in this paper. For this etching solution, the etching rates of silicon and silicon dioxide were about 1.1μm·min-1 and 0.5nm·min-1, respectively. The etching ratio between (100) and (111) planes was about 34:1, and the etched surface was very smooth.

Synthesis of α-hydroxy ketones by copper（Ⅰ）-catalyzed hydration of propargylic alcohols: CO2 as a cocatalyst under atmospheric pressure

Inexpensive and efficient Cu(Ⅰ) catalysis is reported for the synthesis of α-hydroxy ketones from propargylic alcohols, CO2, and water via tandem carboxylative cyclization and nucleophilic addition reaction. Notably, hydration of propargylic alcohols can be carried out smoothly under atmospheric CO2 pressure, generating a series of α-hydroxy ketones efficiently and selectively. This strategy shows great potential for the preparation of valuable α-hydroxy ketones by using CO2 as a crucial cocatalyst under mild conditions.

Selective C3-alkenylation of oxindole with aldehydes using heterogeneous CeO2 catalyst

We report herein that a commercially available CeO2 is an active and reusable catalyst for the C3-selective alkenylation of oxindole with aldehydes under solvent-free conditions. This catalytic method is generally applicable to different aromatic and aliphatic aldehydes, giving 3-alkyledene-oxindoles in high yields(87%–99%) and high stereoselectivities(79%–93% to E-isomers). This is the first example of the catalytic synthesis of 3-alkenyl-oxindoles from oxindole and various aliphatic aldehydes. The Lewis acid-base interaction between Lewis acid sites on CeO2 and benzaldehyde was studied by in situ IR. The structure-activity relationship study using CeO2 catalysts with different sizes suggests that defect-free CeO2 surface is the active site for this reaction.

Selective Se doping of NiFe_(2)O_(4) on an active NiOOH scaffold for efficient and robust water oxidation

There remains a challenge in designing electrocatalysts for water oxidation to create highly efficient catalytic sites for the oxygen evolution reaction(OER)while maintaining their robustness at large outputs.Herein,an etching-assisted synthesis approach was developed to integrate highly active NiFe2O4 nanoparticles with a robust and active NiOOH scaffold directly on commercial stainless steel.A precise selenization strategy was then introduced to achieve selective Se doping of NiFe2O4 to further enhance its intrinsic OER activity while maintaining a three-dimensional NiOOH nanosheet array as a robust scaffold for prompt mass transfer and gas evolution.The resulting NiFe2O4-xSex/NiOOH electrode exhibited superior electrocatalytic activity with low overpotentials of 153 and 259 mV to deliver benchmark current densities of 10 and 500 mA cm^(−2),respectively.More importantly,the catalyst exhibited remarkable durability at a stable current output of 100 mA cm^(−2)for hundreds of hours.These findings may open up opportunities for exploring efficient and robust electrocatalysts for scalable hydrogen production with practical materials.

Continuous Flow Reactor for Hydroxylation of Benzene to Phenol by Hydrogen Peroxide

The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe （Fe/AC） in acetonitrile using H2O2 as the oxidant was studied in a continuous flow reactor. Results showed that the continuous operation could obtain high phenol yield of 28.1%, coupled with the turnover frequency of 3 h^-1, and high selectivity of 98% under mild condition. The catalyst was characterized by N2 adsorption/desorption, Boehm titration, X-ray photoelectron spectra, and Fourier transform infrared spectroscopy. It was observed that iron may interact with the carboxyl group forming iron-carboxylate like species, which act as the active phase. The apparent activation energy obtained by fitting an Arrhenius model to the experimental data was 13.4 kJ/mol. The reaction order was calculated to be about i, 0.2 for benzene and 0.7 for H202.