GREEN CHEMISTRY
·
2018
·Vol. 21
·期 3
·567-577
·
IF 8.586
Wenfeng Zhao,Xiaoping Chi,Hu Li,Jian He,Jingxuan Long,Yufei Xu,Song Yang
Catalytic fixation of CO2 to produce valuable fine chemicals is of great significance to develop a green and sustainable circulation of excessive carbon in the environment. Herein, a series of non-toxic, biodegradable and recyclable acetylcholine-carboxylate bio-ionic liquids with different cations and anions were simply synthesized for producing formamides and methylamines using atmospheric CO2 as a carbon source, and phenylsilane as a hydrogen donor. The selectivity toward products was tuned by altering the reaction temperature under solvent or solvent-free conditions. N-Methylamines (ca. 96% yield) were obtained in acetonitrile at 50 °C, while N-formamides (ca. 99% yield) were attained without a solvent at 30 °C. The established bio-ionic liquid catalytic system found a wide range of applicability in substrates and possessed a high potentiality in scale-up to gram-grade production. The developed catalytic system was fairly stable, which could be easily reused without an apparent loss of reactivity, possibly due to the strong electrostatic interactions between the cation and anion. The combination of experimental and computational results explicitly elucidated the reaction mechanism: PhSiH3 activated by a bio-IL was favorable for the formation of silyl formate from hydrosilylation of CO2, followed by a reaction with an amine to give an N-formamide, while an N-methylamine was formed by further hydrosilylation of the N-formamide.
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JOURNAL OF SEPARATION SCIENCE
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2018
·Vol. 42
·期 4
·888-896
·
IF 2.415
Tianfu Wei,Gongke Li,Zhuomin Zhang
Covalently cross-linked microporous polymers are a new class of highly cross-linked porous network materials with large surface area and potential superiority in sample pretreatment. In this work, a covalently cross-linked microporous polymer was well designed and synthesized by condensation of acylhydrazines in terephthalic dihydrazide with aldehyde groups in 1,3,5-benzenetricarboxaldehyde. The adsorption mechanism was explored and discussed based on π-π stacking interaction and steric effect. Then, a covalently cross-linked microporous polymer was employed as the adsorbent of online micro-solid-phase extraction coupled with high-performance liquid chromatography for the enrichment and analysis of trace pesticide residues in citrus fruits. The method was successfully applied to the online analysis of sugar orange and Huangdigan samples with the detection limits of 0.10–0.30 μg/kg. It was satisfactory that chlorpifos and triazophos in real sugar orange and Huangdigan samples could be actually found and quantified at concentrations of 0.20 and 0.51 mg/kg, respectively. The recoveries of sugar orange and Huangdigan samples were in the range of 70.0–103 and 74.0–119% with relative standard deviations of 0.4–9.7 and 0.5–9.2% ( n = 3), respectively. The proposed method was accurate, reliable, and convenient for the online simultaneous analysis of trace pesticide residues in citrus fruits.
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Current Green Chemistry
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2019
·Vol. 6
·期 2
·127-134
·
IF 0
Yu Zhaozhuo,Xu Fusheng,Li Yan,Konno Hiroyuki,Li Hu,Yang Song
Hydrogenation of furfural (FUR) to furfuryl alcohol (FFA) is a key step and one of the representative examples for comprehensive utilization of biomass, while relatively harsh conditions are typically required to achieve satisfactory results using molecular hydrogen, formic acid, or
alcohol as H-donor over expensive metal catalysts. In this work, a new and benign reaction system, composed of green and cheap tetraethylammonium fluoride and polymethylhydrosiloxane (PMHS), is developed to be efficient for transfer hydrogenation of bio-based FUR to high-value FFA under mild
conditions. After reacting at 35 132;ƒ for 0.5 h, 94.9% FUR conversion and 92.3% yield of FFA could be achieved. This protocol is also widely applicable to the selective reduction of various aromatic aldehydes, giving relevant alcohols in high yields of 81.0-99.9% at 35-60 °C within
30-120 min. Moreover, the mechanism of fluoride-activated hydrosilylation was demonstrated to be responsible for the efficient transfer hydrogenation process.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Mengqi Zheng,Chunyan Xu,Dan Zhong,Yuxing Han,Zhengwen Zhang,Hao Zhu,Hongjun Han
In current study, the degradation of aromatic cyclic organics (ACOs) of coal pyrolysis wastewater (CPW) by lignite activated coke-active sludge (LAC-AS) process was investigated through the insight into synergistic effect of LAC and microbial community. As a contrast, the study on single AS process revealed that high phenols (>200 mg·L −1 ) exerted irreversible toxicity by eliminating biomass. Meanwhile, quinoline and naphthalene exhibited joint inhibition with phenols on bio-community. Absence of functional genus and insufficient interspecific cooperation caused interrupted biological reaction, leading to degenerated ecosystem and vicious circle. However, LAC-AS performed synergistic degradation of ACOs, leading to developed ecosystems and benign substance metabolisms. Specifically, LAC alleviated toxicity on suspended AS by ACOs adsorption, and the facultative bacteria enriched by LAC exerted synergistic degradation in biochemical processes. Firstly, the bacteria on biofilm facilitated direct interspecies electron transfer for ring-cleavage reaction, and electroactive bacteria ( Cloacibacterium , Hydrogenophaga and Stenotrophomonas ) were critical for the process. Secondly, suspended AS further degraded ring-cleavage products, achieving the interspecific cooperation with biofilm. The synergistic nitrogen metabolism by different paths also contributed to the benign metabolic circulation.
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JOURNAL OF CHROMATOGRAPHY A
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2019
·
IF 3.858
Xiaolan Wang,Xufeng Meng,Qiuhua Wu,Chun Wang,Zhi Wang
A solid phase extraction (SPE) method with a porous organic polymer as adsorbent was established for the extraction of five carbamate pesticides (metolcarb, carbaryl, isoprocarb, bassa and diethofencarb) from milk, white wine and juice samples prior to high performance liquid chromatography-diode array detection. The main factors affecting the SPE were optimized, including sample volume, sample loading rate, sample solution pH, desorption conditions and cartridge reusability. Under the optimal conditions, a good linearity existed in the range from 1.0 to 320.0 ng mL −1 for milk and white wine samples and from 0.5 to 160.0 ng mL −1 for juice sample with the correlation coefficients between 0.9956 and 0.9998. The method recoveries of the carbamates were 82.0%–110.0%. The limits of detection were 0.12-0.40 ng mL -1 for milk and white wine samples, and 0.06-0.20 ng mL −1 for juice sample. The adsorption mechanism of the adsorbent was investigated by the extraction of different types of organic compounds (carbamates, benzoylurea insecticides, endocrine disrupting chemicals and polycyclic aromatic hydrocarbons) with the adsorbent. The results showed that the existence of the hydrogen-bonding between the adsorbent and the analytes is favorable for the adsorption and strong hydrophobicity seems to have an adverse effect.
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APPLIED PHYSICS B-LASERS AND OPTICS
·
2018
·Vol. 125
·期 1
·1-12
·
IF 1.881
Zhang Yiran,Wang Lijun,Liu Peng,Li Youping,Zhan Reggie,Huang Zhen,Lin He
The laser-induced fluorescence technique is widely used in the measurement of polycyclic aromatic hydrocarbons (PAHs) in sooting flames. One of the main limitations is the absence of the PAH fluorescence spectra at elevated temperatures. In this study, fluorescence spectra and photophysical properties of five typical PAHs were experimentally studied in the temperature range of 673–1373 K in an optical cell. The experimental results indicated that the fluorescence spectra of PAHs were greatly sensitive to PAH structures and were likely to shift to the red and became broader as temperature increases. Further, we also observed that absorption cross sections of PAHs increased linearly as a function of temperature. Fluorescence quantum yields, which were calculated using integral fluorescence intensities and absorption cross sections, decreased monotonically with increasing temperature. However, the descent gradients of different PAHs were quite different, e.g., naphthalene, fluoranthene and fluorene were more sensitive to temperature, and their fluorescence production was much lower at elevated temperature compared with phenanthrene and pyrene. In order to investigate the fluorescence quantum yields at higher temperatures (up to 2000 K), which cannot be measured in the optical cell, a multistep decay model was established and optimized based on experimental results. At temperatures between 1373 and 2000 K, the extrapolation results indicated that fluorescence quantum yields of phenanthrene and pyrene would be two orders of magnitude higher than those of naphthalene, fluorene and fluoranthene. This contributed to explaining that the PAH fluorescence signals emitted from phenanthrene and pyrene were stronger than those emitted from naphthalene in flames, although the concentrations of phenanthrene and pyrene were much lower than that of naphthalene in flames.
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JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Xingyun Zhao,Shengju Liu,Jiaxi Peng,Xin Li,Huan Niu,Hongyan Zhang,Li Wang,Ren’an Wu
A new hydrothermal carbon was prepared by a “one-pot” hydrothermal transformation of β-cyclodextrin on silica microspheres (noted as [email protected] microspheres), which was featuring as a new stationary phase for the hydrophilic interaction liquid chromatography (HILIC). The synthesized [email protected] possessed polar groups of hydroxyl, carbonyl and carboxyl groups arising from the carbonization transformation of β-cyclodextrin. As demonstrating great hydrophilicity, the [email protected] was applied as an excellent HILIC stationary phase for the separation of polar compounds including phenols and the endocrine disrupting chemicals (EDCs). In comparison with commercial available HILIC stationary phases, the separation performance of the [email protected] stationary phase was superior in the separation of phenols and EDCs. The mild hydrothermal carbon transformation of the β-cyclodextrin on the silica microspheres in the “one-pot” manner would represent a new and simple approach to prepare a new class of saccharide-derived stationary phases by using saccharides as precursors.
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MICROCHEMICAL JOURNAL
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2019
·
IF 3.206
Fengkai Shang,Yutian Wang,Junzhu Wang,Ling Zhang,Pengfei Cheng,Shutao Wang
The content of polycyclic aromatic hydrocarbons (PAHs) in tea has attracted widespread attention. In this study, the strategy of four-way fluorescence data coupled with third-order calibration method based on four way parallel factor analysis (four-way PARAFAC) was used to determine phenanthrene , naphthalene and acenaphthene in tea. A new method, introducing an additional temperature mode into the three-way fluorescence data set, was proposed to acquire a four-way data array. The feasibility of the method was validated by experiments. The four-way PARAFAC could give satisfactory analytical results for the determination of three PAHs in tea. The average spiked recoveries were (100.9 ± 7.8)% for phenanthrene, (94.6 ± 8.6)% for naphthalene, (96.0 ± 9.8)% for acenaphthene. The root-mean-square error of prediction (RMSEP) values were 0.495 μg L −1 for phenanthrene, 0.841 μg L −1 for naphthalene, 0.577 μg L −1 for acenaphthene. The average relative predictive errors (ARPE) values for three PAHs were <2.35%. The limits of detection (LOD) of three PAHs were between 0.026 and 0.14 μg L −1 . Generally, these results obtained by four-way PARAFAC were better than that of three-way PARAFAC. In addition, analytical figures of merit, such as Sensitivity, Selectivity and Analytical sensitivity, were calculated for three PAHs to evaluate the methods. The results demonstrated that the four-way PARAFAC was more suitable for the determination for three target analytes in this study.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Xiang-Dong Qing,Huai-Bo Zhou,Xiao-Hua Zhang,Hai-Long Wu,Chang-Ya Chen,Su-Wen Xu,Shuang-Shuang Li
Polycyclic aromatic hydrocarbons (PAHs) are of worldwide environmental concern because of their properties of carcinogenicity, mutagenicity and teratogenicity. In the work, a smart combination of gel permeation chromatography-diode array detector and second-order calibration based on alternating trilinear decomposition (ATLD-GPC-DAD) is proposed for simultaneous targeted identification and quantification of 15 PAHs in atmospheric pollution sources such as flue-dust and greasy-dirt samples. No need of tedious sample pretreatment and specific PAHs separation column, severely overlapped chromatograph peaks are successfully resolved by the ATLD-GPC-DAD method even with only 3 s of difference in retention times. Accurate quantitative results of 15 PAHs are achieved by using the developed method even in the presence of unexpected interferents. The limits of detection range from 0.94 ng mL −1 to 48.86 ng mL −1 , and the average recoveries are in the range of (81.2 ± 1.0)% to (108.9 ± 11.6)% for flue-dust samples and (89.7 ± 3.4)% to (107.5 ± 8.0)% for greasy-dirt samples. The sensitivity and selectivity of analytes is significantly improved with the aid of “mathematical separation” of the method. These results indicate that it opens a promising analytical strategy for control of PAHs emissions and management of urban air quality.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Hao Chen,Hao Cheng,Feng Zhou,Kequan Chen,Kai Qiao,Xiuyang Lu,Pingkai Ouyang,Jie Fu
The synthesis of highly selective catalysts for the catalytic fast pyrolysis (CFP) of biomass into valuable aromatics remains a challenge. This report describes the synthesis of hierarchical ZSM-5 catalysts by the NaOH desilication of conventional HZSM-5 for the CFP of rice straw to aromatics in a Tandem μ-reactor system coupled directly to a GC/MS equipped with FID and TCD. Catalysts were treated with a mild HCl wash and metal loading to increase the catalytic activity and reduce the deactivation. The effects of acidity, mesoporosity and incorporation of metals on the production of aromatics were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption and desorption (N 2 -BET) and temperature-programmed desorption of NH 3 (NH 3 -TPD). The highest total acidity, especially the strong acidity, of the hierarchical ZSM-5 treated by 0.2 and 0.4 NaOH followed by HCl washing (AHZ-0.2 and AHZ-0.4) gave the highest yields of aromatics. Suitable mesopores introduced by alkali treatment enhanced mass transfer of reactants, increasing the yield of aromatics. Finally, the loading of a suitable amount of Ni and Cu produced more aromatics than standard HZSM-5 due to the improved decarboxylation/decarbonylation reactions leading to higher yields of olefins.
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ADSORPTION SCIENCE & TECHNOLOGY
·
2018
·
IF 0.609
Liyun Yang,Xiaoming Qian,Zhi Wang,Yuan Li,Hao Bai,Hong Li
This study investigates the removal effectiveness and characteristics of phenanthrene and naphthalene using low-cost steel slag with batch experiments. The adsorption characteristics of steel slag were measured and analysed using X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy. The batch experiments investigated the effect of the time gradient, pH, and steel slag dosage gradient on the adsorption of the steel slag. The results show that with time and dosage of steel slag increased, the adsorption capacity of phenanthrene and naphthalene increased and gradually became balanced, but pH had no obvious effect on the adsorption of phenanthrene and naphthalene. The Langmuir isotherm model best describes the phenanthrene and naphthalene removal by the steel slag, which shows the adsorption occurring in a monolayer. The maximum adsorption capacity of the steel slag to phenanthrene and naphthalene is 0.043 and 0.041 mg/g, respectively. A pseudo-first-order kinetic model can better represent the adsorption of phenanthrene and naphthalene by steel slag. The research demonstrates that the steel slag has a certain adsorption capacity for phenanthrene and naphthalene.
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ANALYTICA CHIMICA ACTA
·
2018
·
IF 5.123
Yinhui Yang,Zhengfeng Chang,Xiaohong Yang,Meiling Qi,Jinliang Wang
Herein we report a propeller-like hexaphenylbenzene-based hydrocarbon material (denoted as BT) as the stationary phase for capillary gas chromatography (GC). The statically-coated BT capillary column showed a high column efficiency of 4340 plates m −1 and weak polarity. Owing to its unique conformation, π-electron toroidal delocalization and intrinsic microporosity , the BT stationary phase exhibited interesting selectivity for aromatic compounds over alkanes. Compared with the graphene (G) column, the BT column showed much prolonged retention and high selectivity for aromatic isomers, especially methylnaphthalenes , dimethylnaphthalenes and phenanthrene/anthracene, mainly because of its propeller-like conformation with rich intercalation effects. Moreover, it exhibited good column repeatability (intra-day, inter-day) and reproducibility (between-column) with RSD values on the retention times less than 0.08% for intra-day, 0.32% for inter-day and 3.8% for between-column, respectively. Also, it showed good potential for determination of minor isomer impurities in real samples. To the best of our knowledge, this work presents the first example of employing an neat aromatic hydrocarbon material as the GC stationary phase with high selectivity for analytes of a wide ranging polarity.
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