Synthesis and Characterization of Silicone Modified Polyurethane Surfactant Useable at High Temperature

A series of novel silicone modified polyurethane (Si-PU) surfactants were successfully synthesized by using hydroxypropyl-terminated polydimethylsiloxane (HPMS), polyethylene glycol (PEG), dimethylolpropionic acid (DMPA) and isophoronediisocyanate (IPDI). The chemical structure of the surfactant was confirmed by FTIR and ¹H-NMR. TEM photographs showed that the micelles of the Si-PU surfactants dispersed in aqueous solution were spherical with the particle size in the range of 100–400 nm. Surface tension measurements indicated that these surfactants had low surface tension to 29.9 mN·m^?1and a definite critical micelle concentration to, approximately 5.0×10^?4–7.5×10^?4mol·L^?1. When the content of HPMS was 20 wt%, the surfactant's, emulsifying performance was superior to the traditionally available Span80/Tween80 mixed emulsifiers. In addition to that, no phase transition temperature was detected from 20°C to 90°C by fluorescence probe and DSC measurements, confirming the high thermal stability of the micelles.     

CuI‐Catalyzed Multicomponent Synthesis of Aminoindolizines from Aldehydes,Amines, and Alkynes under Solvent‐Free Conditions

A direct and efficient approach to 1‐aminoindolizines through three‐component one‐pot reaction of heteroaryl aldehydes, secondary amines and terminal alkynes catalyzed by CuI under solvent‐free conditions has been developed. This methodology provides a rapid access to substituted aminoindolizines with good yields (up to 97%).     

Ir和IrPd催化剂的合成及结构调控对其甲醇氧化性能的影响

以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO₂₀-PPO₇₀-PEO₂₀)为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法能更好地促进Ir前驱体的还原。对于IrPd合金催化剂,溶剂热法可制得表面富含Ir但MOR活性较低的核壳结构产物(IrPd-S)。水热反应得到的不同原子比(IrPd、Ir₂Pd、IrPd₂)的产物粒径更小,元素分布更均匀。其中比例为1∶1的IrPd (IrPd-H)催化剂的MOR电催化活性最高。上述结果表明,通过调节溶剂类型以及P123的结构诱导作用,可以有效地调节纯Ir和IrPd合金催化剂的结构、表面组成和电催化活性。     

Improved Hydrogen‐Storage Thermodynamics and Kinetics for an RbF‐Doped Mg(NH2)2–2 LiH System

The introduction of RbF into the Mg(NH₂)₂–2 LiH system significantly decreased its (de‐)hydrogenation temperatures and enhanced its hydrogen‐storage kinetics. The Mg(NH₂)₂–2 LiH–0.08 RbF composite exhibits the optimal hydrogen‐storage properties as it could reversibly store approximately 4.76 wt % hydrogen through a two‐stage reaction with the onset temperatures of 80 °C for dehydrogenation and 55 °C for hydrogenation. At 130 °C, approximately 70 % of hydrogen was rapidly released from the 0.08 RbF‐doped sample within 180 min, and the fully dehydrogenated sample could absorb approximately 4.8 wt % of hydrogen at 120 °C. Structural analyses revealed that RbF reacted readily with LiH to convert to RbH and LiF owing to the favorable thermodynamics during ball‐milling. The newly generated RbH participated in the following dehydrogenation reaction, consequently resulting in a decrease in the reaction enthalpy change and activation energy.     

A High Yield Method of Extracting Alkaloid from Aconitum coreanum by Pulsed Electric Field

A high yield method to extract alkaloids from Aconitum coreanum using pulsed electric field (PEF) was developed, and the optimized extraction method compared to the other four extraction methods, consisting of cold maceration extraction, percolation extraction, heat reflux extraction (HRE), and ultrasonic-assisted extraction (UE). The experimental factors of the extraction methods such as electric field intensity, pulse frequency and solid-to-solvent ratio were evaluated. The content of Guanfu base A (GFA) was quantified by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The results indicated that the highest yield of GFA was 3.94 mg g^?1 by PEF with conditions of 20 kV cm^?1 electric field intensity, 8 pulse, 1:12 solid-to-solvent ratio, and 90 % ethanol–water solution. Meanwhile, the extraction time of PEF was <1 min, which is much less than the HRE of 10 h and even the newly used technique UE of 40 min. Moreover, the results of PEF extraction method showed obvious advantages, with the highest efficiency (120 L h^?1), the shortest extraction time (0.5–1 min), and the lowest energy costs, which could be applied in the industrial production of alkaloids from A. coreanum. Therefore, the application of the PEF extraction method is a promising and constructive method for extraction of GFA.     

One‐Pot and Convenient Conversion of 5‐Azidopyrazole‐4‐carboxaldehyde to Pyrazolo[3,4‐b]pyridines

A one‐pot and convenient synthesis of multisubstituted pyrazolo[3,4‐b]pyridines in moderate to high yields has been achieved by a two‐step reaction: diazo‐transfer of 5‐azido‐1‐phenylpyrazole‐4‐carboxaldehydes to ketones in ethanolic KOH to give 5‐amino‐1‐phenylpyrazole‐4‐carboxaldehyde and subsequent Friedlaender reaction of 5‐amino‐1‐phenylpyrazole‐4‐carboxaldehyde with ketones.     

Extraction of tributyltin by magnetic molecularly imprinted polymers

We have prepared core-shell magnetic molecularly imprinted polymer nanoparticles for recognition and extraction of tributyl tin (TBT). The use of particles strongly improves the imprinting effect and leads to fast adsorption kinetics and high adsorption capacities. The functional monomer acrylamide was grafted to the surface of Fe₃O₄ nanospheres in two steps, and MIP layers were then formed on the surface by creating a MIP layer on the surface consisting of poly(ethyleneglycol dimethacrylate) with a TBT template. The particles were characterized in terms of morphological, magnetic, adsorption, and recognition properties. We then have developed a method for the extraction of TBT from spiked mussel (Mytilidae), and its determination by liquid chromatography-tandem mass spectrometry. The method has a limit of detection of 1.0 ng?g^?1 (n?=?5) of TBT, with a linear response between 5.0 and 1,000 ng?g^?1. The proposed method was successfully applied to the determination of trace TBT in marine food samples with recoveries in the range of 78.3–95.6 %.

Preparation and Characterization of Styrene/Butyl Acrylate Emulsifier-Free Latex with 2-Acrylamido-2-Methyl Propane Sulfonic Acid as a Reactive Emulsifier

A kind of emulsifier-free latex (FL) was successfully synthesized from styrene (St) and butyl acrylate (BA) with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) as a reactive emulsifier. The particle size of latex particles, stability against electrolytes, minimum film forming temperature (MFT) and water contact angle (CA) were evaluated and compared with a conventional latex (CL). Test results show that FL has larger particle size, better stability against electrolytes and lower MFT value compared with CL; higher AMPS content leads to smaller particle size and smaller water CA.     

Fractal Aperture Distribution of Activated Carbon Fiber and Adsorption Behavior to Low‐Density Benzene Steam

Based on the J(x) fractal distribution function of aperture given by Jaroniec, this article suggests another function K(x), a variant of J(x) but offering new insight. We then use these two functions to characterize three kinds of activated carbon fiber (ACF) of different specific areas. This article also provides the fractal distribution of the aperture and the isotherm of nonpolarity benzene steam on the ACF specimens and the relationship between them.     

高效液相色谱法同时测定催化反应液中氨基葡萄糖盐酸盐和氨基葡萄糖酸

向制备氨基葡萄糖酸的催化反应液中加入亚硝酸盐试剂,在25℃下衍生反应5 min,所得含有氨基葡萄糖盐酸盐和氨基葡萄糖酸衍生物的溶液用作高效液相色谱分析。选用AminexHPX-87H离子排斥色谱柱为固定相,以5 mmol·L^-1硫酸溶液为流动相进行淋洗,用示差折光检测器进行检测,提出了同时测定氨基葡萄糖盐酸盐和氨基葡萄糖酸的高效液相色谱法。2种化合物的色谱峰面积与其浓度均在50 mmol·L^-1以内呈线性关系,检出限（3S/N）依次为0.014,0.034 mmol·L^-1。方法用于5批催化反应液中氨基葡萄糖盐酸盐和氨基葡萄糖酸的测定,加标回收率依次在99.3%～100%,99.2%～102%之间;测定值的相对标准偏差均小于2.5%。