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Kinetics of halogen-exchange fluorination of 2,6-dichlorobenzaldehyde

LIANG Zhengyong, LI Bindong, FENG Chao

《化学科学与工程前沿（英文）》 2008年第2卷第1期页码 59-62 doi: 10.1007/s11705-008-0008-1

摘要： Under the conditions of phase transfer catalysis and nitrobenzene as the solvent, the halogen-exchange fluorination of 2,6-dichlorobenzaldehyde using KF as fluorinating agent was studied. The kinetics was investigated and the reaction rate constants were obtained under the optimum conditions of (KF):(2,6-dichlorobenzaldehyde):(PhPBr):n(acetone-furan crown ether) = 4:1:0.1:0.05 and temperatures of 433 K, 443 K, 453 K and 463 K. The results illustrated the activation energy of the first and the second step is 4.57 × 10 J·mol and 3.53 × 10 J·mol, respectively. The pre-exponential factor is 4.50 × 10 h and 1.08 × 10 h, respectively. Thus a reliable kinetics data could be obtained for further research.

关键词： reaction solvent transfer catalysis activation nitrobenzene

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Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient pressure

Yujing Liu, Xiao Han, Balati Kuerbanjiang, Vlado K. Lazarov, Lidija Šiller

《化学科学与工程前沿（英文）》 2021年第15卷第4期页码 954-959 doi: 10.1007/s11705-020-2028-4

摘要： Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent. We prepared silica aerogels with a density and a specific surface area of 0.053 g∙cm and 423 m ∙g , respectively. The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm ∙g . Further, the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°, which indicates a super-hydrophobic surface of aerogels.

关键词： silica aerogel methyltrimethoxysilane solvent exchange sodium bicarbonate trimethylchlorosilane ambient pressure drying

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Heat, mass, and work exchange networks

Zhiyou CHEN, Jingtao WANG

《化学科学与工程前沿（英文）》 2012年第6卷第4期页码 484-502 doi: 10.1007/s11705-012-1221-5

摘要： Heat (energy), water (mass), and work (pressure) are the most fundamental utilities for operation units in chemical plants. To reduce energy consumption and diminish environment hazards, various integration methods have been developed. The application of heat exchange networks (HENs), mass exchange networks (MENs), water allocation heat exchange networks (WAHENs) and work exchange networks (WENs) have resulted in the significant saving of energy and water. This review presents the main works related to each network. The similarities and differences of these networks are also discussed. Through comparing and discussing these different networks, this review inspires researchers to propose more efficient and convenient methods for the design of existing exchange networks and even new types of networks including multi-objective networks for the system integration in order to enhance the optimization and controllability of processes.

关键词： process system engineering integration methods heat exchange network mass exchange network work exchange network

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Regulation of radicals by hydrogen-donor solvent in direct coal liquefaction

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1689-1699 doi: 10.1007/s11705-022-2186-7

摘要： Radicals are important intermediates in direct coal liquefaction. Certain radicals can cause the cleavage of chemical bonds. At high temperatures, radical fragments can be produced by the splitting of large organic molecules, which can break strong chemical bonds through the induction pyrolysis of radicals. The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis. Using the hydroxyl and ether bonds as indicators, the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments. Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogen-donor solvents. Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution. The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.

关键词： direct coal liquefaction hydrogen-donor solvent induced pyrolysis radical mechanism density functional theory calculations

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Micronization of curcumin with biodegradable polymer by supercritical anti-solvent using micro swirl

Kimthet Chhouk, Wahyudiono, Hideki Kanda, Shin-Ichro Kawasaki, Motonobu Goto

《化学科学与工程前沿（英文）》 2018年第12卷第1期页码 184-193 doi: 10.1007/s11705-017-1678-3

摘要： Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and anti-microbial activity. In this work, a swirl mixer was employed to produce the micronized curcumin with polyvinylpyrrolidone (PVP) by the supercritical anti-solvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1:30, feed concentration of 5 mg·mL , temperature of 40 °C, pressure of 15 MPa, and CO flow rate of 15 mL·min . Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.

关键词： micronization curcumin polyvinylpyrrolidone supercritical anti-solvent swirl mixer

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Study of an artificial boundary condition based on the damping-solvent extraction method

Qiang XU, Jianyun CHEN, Jing LI, Mingming WANG

《结构与土木工程前沿（英文）》 2012年第6卷第3期页码 281-287 doi: 10.1007/s11709-012-0167-5

摘要： A new artificial boundary condition for time domain analysis of a structure-unlimited-foundation system was proposed. The boundary condition was based on the damping-solvent extraction method. The principle of the damping-solvent extraction method was described. An artificial boundary condition was then established by setting two spring-damper systems and one artificial damping limited region. A test example was developed to verify that the proposed boundary condition and model had high precision. Compared with the damping-solvent extraction method, this boundary condition is easier to be applied to finite element method (FEM)-based numerical calculations.

关键词： damping-solvent extraction method structure-unlimited-foundation system spring-damper system artificial damping limited region finite element method

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Deep eutectic solvent inclusions for high- composite dielectric elastomers

《化学科学与工程前沿（英文）》 2022年第16卷第6期页码 996-1002 doi: 10.1007/s11705-022-2138-2

摘要： Recent advances in novel electroactive devices have placed new requirements on material development. High-performance dielectric elastomers with good mechanical stretchability and high dielectric constant are under high demand. However, the current strategy for fabricating these materials suffers from high cost or low thermal stability, which greatly hinders large-scale industrial production. Herein, we have successfully developed a novel strategy for improving the dielectric constant of polymeric elastomers via deep eutectic solvent inclusion by taking advantage of the low cost, convenient and environmentally benign synthesis process and high ionic conductivity from deep eutectic solvents. The as-prepared composite elastomers showed good stretchability and a greatly enhanced dielectric constant with a negligible increase in dielectric dissipation. Moreover, we have proven the universality of our strategy by using different types of deep eutectic solvents. It is believed that low-cost, easy-synthesis and environmentally friendly deep eutectic solvents including composite elastomers are highly suitable for large-scale industrial production and can greatly broaden the application fields of dielectric elastomers.

关键词： composite materials deep eutectic solvent dielectric elastomer high dielectric constant

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A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid

Tingting MA, Ying TENG, Peter CHRISTIE, Yongming LUO, Yongshan CHEN, Mao YE, Yujuan HUANG

《环境科学与工程前沿（英文）》 2013年第7卷第1期页码 31-42 doi: 10.1007/s11783-012-0463-2

摘要： An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di- -butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg to a range of 90– 290 μg·kg . Linearity of response between 20 μg·L and 2 mg·L was also established and the correlation coefficients ( ) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.

关键词： phthalic acid esters quality assurance and quality control soil type accelerated solvent extraction certified reference materials

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TiO supported IrO for anode reversal tolerance in proton exchange membrane fuel cell

《能源前沿（英文）》 2022年第16卷第5期页码 852-861 doi: 10.1007/s11708-021-0811-7

摘要： Fuel starvation can occur and cause damage to the cell when proton exchange membrane fuel cells operate under complex working conditions. In this case, carbon corrosion occurs. Oxygen evolution reaction (OER) catalysts can alleviate carbon corrosion by introducing water electrolysis at a lower potential at the anode in fuel shortage. The mixture of hydrogen oxidation reaction (HOR) and unsupported OER catalyst not only reduces the electrolysis efficiency, but also influences the initial performance of the fuel cell. Herein, Ti₄O₇ supported IrO_x is synthesized by utilizing the surfactant-assistant method and serves as reversal tolerant components in the anode. When the cell reverse time is less than 100 min, the cell voltage of the MEA added with IrO_x/Ti₄O₇ has almost no attenuation. Besides, the MEA has a longer reversal time (530 min) than IrO_x (75 min), showing an excellent reversal tolerance. The results of electron microscopy spectroscopy show that IrO_x particles have a good dispersity on the surface of Ti₄O₇ and IrO_x/Ti₄O₇ particles are uniformly dispersed on the anode catalytic layer. After the stability test, the Ti₄O₇ support has little decay, demonstrating a high electrochemical stability. IrO_x/Ti₄O₇ with a high dispersity has a great potential to the application on the reversal tolerance anode of the fuel cell.

关键词： proton exchange membrane fuel cell (PEMFC) fuel starvation cell reverse reversal tolerance anode oxygen evolution reaction

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Control strategies for disinfection byproducts by ion exchange resin, nanofiltration and their sequential

《环境科学与工程前沿（英文）》 2023年第17卷第10期 doi: 10.1007/s11783-023-1725-x

摘要：

● Effects of AER adsorption and NF on DBP precursors, DBPs, and TOX were examined.

关键词： Disinfection byproducts Control Anion exchange resin Nanofiltration Cytotoxicity

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Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

《环境科学与工程前沿（英文）》 2023年第17卷第2期 doi: 10.1007/s11783-023-1625-0

摘要：

● IEM ion/ion selectivities of charge, valence, & specific ion are critically assessed.

关键词： Ion-exchange membranes Selectivity Separations

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Purification of artemisinin from quercetin by anti-solvent crystallization

Chandrakant R. MALWADE, Haiyan QU, Ben-Guang RONG, Lars P. CHRISTENSEN

《化学科学与工程前沿（英文）》 2013年第7卷第1期页码 72-78 doi: 10.1007/s11705-013-1305-x

摘要： In the present work, anti-solvent crystallization of artemisinin from four different organic solvents (methanol, ethanol, acetonitrile, and acetone) was studied. Water was used as anti-solvent. The effect of an impurity (quercetin) on the performance of anti-solvent crystallization of artemisinin was investigated. The fundamental process data such as solubility of artemisinin in pure organic solvents and their binary mixtures with varying composition water were measured at room temperature. The solubility of quercetin was measured only in pure organic solvents at room temperature. Anti-solvent crystallization experiments were designed based on the fundamental process data determined. Firstly, the anti-solvent crystallization of artemisinin without impurity was performed from all four organic solvents and then the experiments were repeated with addition of an impurity (quercetin) while keeping all other process parameters constant. Two different concentrations of impurity, i.e., 10% and 50% of its solubility, in the respective organic solvents at room temperature were used. The effect of impurity on performance of anti-solvent crystallization was evaluated by comparing the yield and purity of the artemisinin obtained with those in the absence of impurity. Results of the present work demonstrated that the presence of quercetin in the solution does not affect the final yield of artemisinin from the solution of each of four organic solvents used. However, the purity of artemisinin crystals were reduced when quercetin concentration was 50% of its solubility in all solvents studied.

关键词： anti-solvent crystallization artemisinin quercetin solubility Artemisia annua

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Review of solvent based carbon-dioxide capture technologies

Kathryn A. MUMFORD,Yue WU,Kathryn H. SMITH,Geoffrey W. STEVENS

《化学科学与工程前沿（英文）》 2015年第9卷第2期页码 125-141 doi: 10.1007/s11705-015-1514-6

摘要： Currently, a large proportion of global fossil fuel emissions originate from large point sources such as power generation or industrial processes. This trend is expected to continue until the year 2030 and beyond. Carbon capture and storage (CCS), a straightforward and effective carbon reduction approach, will play a significant role in reducing emissions from these sources into the future if atmospheric carbon dioxide (CO ) emissions are to be stabilized and global warming limited below a threshold of 2 °C. This review provides an update on the status of large scale integrated CCS technologies using solvent absorption for CO capture and provides an insight into the development of new solvents, including advanced amine solvents, amino acid salts, carbonate systems, aqueous ammonia, immiscible liquids and ionic liquids. These proposed new solvents aim to reduce the overall cost CO capture by improving the CO absorption rate, CO capture capacity, thereby reducing equipment size and decreasing the energy required for solvent regeneration.

关键词： large scale carbon dioxide carbon capture solvent absorption

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Electro-assisted regeneration of ion exchange resins

LIU Zhigang, WANG Ying, LI Yansheng, CHANG Hui

《环境科学与工程前沿（英文）》 2008年第2卷第4期页码 410-414 doi: 10.1007/s11783-008-0069-x

摘要： Electro-assisted regeneration (EAR) for the mixed bed of strongly acidic cation and weakly basic anion exchange resins with the Al(OH) suspension in a three-compartment cell was investigated. The desalination experiments were carried out to evaluate the characteristic of the regenerated mixed resins. Experimental results showed that the efficiency of resin regeneration was strictly dependent on the voltage, regeneration time, and feed regenerant flow rate. The amount of the effluent reached 50 times the volume of the resins bed, and the conductivity was less than 1.0 ?s/cm. Compared to the conventional ER, the total effluent volume of EAR was about 1000 mL more than that of ER under the same conditions, and the outlet conductivity was significantly lower. The desalination and regeneration reaction mechanisms of the mixed resins indicated the regeneration efficiency of resin with Al(OH) as the regenerant was much higher than that with HO.

关键词： effluent volume acidic three-compartment weakly exchange