SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Zeyu Chang,Xiaoxia Jia,Tong Li,Yong Wang,Libo Li
In the petrochemical industry, the separation of C4 olefins is crucial but a challenging and energy-intensive process. In this study, two fluorinated anion-pillared hybrid ultramicroporous materials (HUMs), namely KAUST-7 (NbOFFIVE-1-Ni) and KAUST-8 (AlFFIVE-1-Ni), were explored for the efficient separation of ternary C4 olefin mixtures (C 4 H 6 /n-C 4 H 8 / iso -C 4 H 8 ) via gate-opening and size-sieving effects. KAUST-7, with a narrow and flexible pore window that completely excludes iso -C 4 H 8 , but allows for the absorption of C 4 H 6 and n-C 4 H 8 through gate-opening effects, with a preferential adsorption of C 4 H 6 due to its easier access to the channel. KAUST-8, on the other hand, with a larger pore window size and the strong H-bond interactions between the electronegative fluorine atoms from inorganic anion pillar and the C4 olefin molecules, efficiently separates iso -C 4 H 8 from C4 olefins, as the adsorption of both C 4 H 6 and n-C 4 H 8 is significantly enhanced while iso -C 4 H 8 retains much lower adsorption capacity. The relationship between the structures and separation properties of these materials is discussed, providing insight into the development of efficient separation materials. Fixed bed breakthrough experiments verify the excellent separation performances of KAUST-7 and KAUST-8 for C 4 H 6 /n-C 4 H 8 / iso -C 4 H 8 , highlighting their potential for industrial applications.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2023
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IF 6.1
Xinjing Li,Yishun Yao,Xue Xia,Foxin Zhang,Jingyang Yu,Heping Cui,Yunwei Niu,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
Until now, no effective method has been found to monitor the Maillard reaction process for complex protein hydrolysates. Dynamic changes in the concentration of α-dicarbonyl compounds, fluorescence intensity, and browning degree were investigated during the Maillard reaction of corn protein hydrolysates. When the fluorescence intensity reached the peak, deoxyosones would continue to be increased by ARP’s degradation. However, the reaction node with the highest fluorescence intensity coincided with the turning point of the browning reaction, and the subsequent browning rate remarkably increased. Therefore, the change in fluorescence intensity could be used to monitor the degradation of ARP and the formation of browning melanoidin at different stages of the Maillard reaction of complex systems, thus effectively indicating the process of the Maillard reaction. When Maillard reaction intermediates (MRIs) with maximum fluorescent compounds were heated, the most abundant pyrazines were subsequently achieved. However, furan compounds would be progressively increased during the thermal process of MRIs with continuously enhanced browning.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2023
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IF 6.1
Yue Luo,Siyue Zhu,Jie Peng,Heping Cui,Qingrong Huang,Baojun Xu,Chi-Tang Ho
Amadori rearrangement products (ARPs), as intermediates of the Maillard reaction (MR), are potential natural flavor additives but there is a lack of investigation especially in oligopeptide-ARPs. This study for the first time conducted a systematic analysis in comparing ARPs of glycine, diglycine, triglycine, and glucose to corresponding classic MR systems, including production, stability, and flavor analysis. The ARPs were effectively produced by prelyophilization with heating at 70 °C for 60 min and purified to 96% by a two-step purification method. Correlated with the stability order of amino compounds (glycine > diglycine > triglycine), the stability order of ARPs was Gly-ARP > Digly-ARP ≈ Trigly-ARP. In a negative correlation with heating temperature and time, ARPs were less stable than original amino compounds at high temperatures (100, 130, and 160 °C). ARPs exhibited better flavor formation ability in pyrazines and furans than MR systems, with similar flavor compositions but different preferences. Diglycine- and triglycine-ARPs exhibited better flavor formation efficiency than glycine-ARP. Heating temperature and time, initial pH, and carbon chain length were found to be the parameters that affect the stability and flavor formation of ARPs. This study suggested that ARPs, especially peptide-ARPs, have great potential for usage as food flavor additives in the future.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2023
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IF 6.1
Tong Zhou,Xue Xia,Heping Cui,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
The contribution of glutathione (GSH) and free amino acids degraded from GSH to the generation of pyrazines and 2,3-butanedione was illustrated during their interaction in the thermal treatment of the Amadori compound of alanine and xylose (ARP). GSH-degraded amino acids, glutamic acid (Glu), cysteine (Cys), and glycine (Gly), but not pyroglutamic acid (pGlu), could effectively capture α-dicarbonyls to facilitate the formation of pyrazines when ARP was heated with GSH. Deoxypentosones, the precursors of 2,3-butanedione, were largely consumed in the ARP–GSH model by the interaction with GSH and its degradative Cys compared with the ARP model. The addition of GSH and deoxypentosones inhibited the further degradation of deoxypentosones, resulting in less formation of 2,3-butanedione and other α-dicarbonyl compounds. Meanwhile, the reaction between GSH-degraded Cys and deoxypentosones to form sulfur-containing compounds such as thiols accelerated the consumption of deoxypentosones; thereby, the formation of 2,3-butanedione was severely interfered. However, this inhibition was compensated for by the GSH-degraded Gly through the addition between Gly and MGO and the subsequent deamination. The involvement of exogenous GSH could simultaneously boost the yields of 2,3-butanedione and pyrazines compared with those of ARP heated alone. As the degree of GSH degradation strengthened in the ARP-thermal-degraded GSH models, the yields of both pyrazines and 2,3-butanedione steadily increased.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2021
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IF 4.464
Xiaofeng Wei,Lishang Li,Huiting Lian,Xuegong Cao,Bin Liu
Due to the widespread application of chiral substances in current society, the electrochemical strategy to assemble chiral metal–organic frameworks (CMOFs) as sensors has shown great potential for sensitive enantiorecognition. In this paper, an efficient and highly selective electrochemical sensor was proposed based on multi-walled carbon nanotube (MWCNT) and CMOF, and successfully achieved sensitive chiral recognition of Tryptophan (Trp) enantiomers . Numerous MOFs in multiple synthesis conditions were investigated for a regular process to access the electrochemical chiral recognition. A variety of amino acids were introduced into the MOFs skeleton by a simple hydrothermal method for the enantio -specificity. Meanwhile the MWCNT smoothly integrated with the CMOF to form a functional electrosensing interface with the increase of conductivity. Based on the current ratio ( R cp ) of tryptophan enantiomers by different modified electrodes , a series of experimental conditions were optimized for the optimal chiral recognition performance of the CMOF/MWCNT-based sensor, finally reaching 2.9 times of ΔI L/D between enantiomers. In addition, D/ l -Trp showed a good linear relationship with the current in the range from 0.4 μM to 19 μM with the detection limit of 0.11 μM for l -Trp and 0.16 μM for d -Trp. The prepared composite-functionalized sensor owned the desired reproducibility and selectivity to identify Tryptophan enantiomers with robust chiral recognition. The research on the structure–activity relationship of chiral MOFs to Tryptophan enantiomers provides a new path to construct more electrochemical sensors for the application of enantiorecognition in pharmaceutical analysis.
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JOURNAL OF CHROMATOGRAPHY A
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2020
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IF 4.049
Sha-Sha Meng,Ze-Rong Tao,Wen-Qi Tang,Ting Han,Yan Du,Zhi-Yuan Gu
ABSTRACT Fine-tuning of the SiF 6 2− -containing metal-organic frameworks (SIFSIX) through the substitution of metal centers and ligands changed the apertures from 8.3 Å to 3.8 Å, resulting in ultramicropores and notably improving the separation performance of alkane isomers. Herein, we reported SIFSIX-1-Zn, SIFSIX-1-Cu and SIFSIX-3-Zn as representative stationary phases for capillary gas chromatography (GC). The capillary column coated with ultramicroporous SIFSIX-3-Zn efficiently separated the alkane isomers and benzene homologues, which outperformed SIFSIX-1-Zn and SIFSIX-1-Cu. This resulted from size matching between the window of the ultramicroporous SIFSIX-3-Zn and the analytes, which was also supported by McReynolds constants, column efficiency and peak tailing effect. It opened up a new avenue for ultramicroporous materials in the chromatography separation of isomers.
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CRYSTAL GROWTH & DESIGN
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2020
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IF 4.089
Mengwei Wang,Yiming Ma,Peng Shi,Shichao Du,Songgu Wu,Junbo Gong
There have been many studies on the preparation of cocrystals based on the synthon structures, but the synthons cannot completely guarantee the formation of cocrystals. On the basis of the widespread presence of the amino-pyridine synthon, we selected nimesulide (NMS) as the host component and a series of pyridine analogues (pyrazine (PYE), 4,4′-bipyridine (BP), trans-1,2-bis(4-pyridyl)ethylene (BPE), 1,2-bis(4-pyridyl)ethyne (BPY), 1,2-bis(4-pyridyl)ethane (BPA), and 1,3-bis(4-pyridyl)propane (BPP)) as coformers and thoroughly explored the difference in the ability of cocrystal formation. We successfully obtained four new cocrystals of NMS-BP/BPE/BPA/BPY, while cocrystals of NMS and PYE/BPP were not identified. By means of structural analysis and theoretical computation, we believe that PYE, with the weakest H-bond acceptor capacity and insufficient benzene ring, has difficulty in constructing a three-dimensional structure with NMS through effective N–H···N H-bonds and π–π stacking. Molecular flexibility could be a great resistance to form a cocrystal between BPP and NMS. Through quantitative calculation of Ridge and Lasso regression, it is found that the molecular electrostatic potential (MESP), h_ema (sum of hydrogen bond acceptor strengths), Kier flex (molecular flexibility), and the horizontal distance of two N atom projections of coformers have a descending effect on the cocrystal formation.
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Green Energy & Environment
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2020
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IF 6.395
Pengfei Liu,Christian Marcus Pedersen,Jiaojiao Zhang,Rui Liu,Zhenzhou Zhang,Xianglin Hou,Yingxiong Wang
Ternary deep eutectic solvents (TDESs) comprising choline chloride (ChCl), glycerol and l -arginine were synthesized as catalysts and solvents for the conversion of d -glucosamine (GlcNH 2 ) into deoxyfructosazine (DOF). The interactions between these three components in the prepared TDESs were studied by 1 H-, 35 Cl-NMR spectra and 1 H diffusion-ordered spectroscopy (DOSY) measurements. The chemical shift changes of active hydrogen in the 1 H-NMR spectra of TDES system and widening of signals in the 35 Cl-NMR spectra confirmed the hydrogen bonding interaction between the components, which was further supported by the decrease of diffusion coefficients ( D ) of the TDES components according to 1 H DOSY measurements. The influences of reaction temperature and l -arginine content in the TDESs on the yield of DOF were also studied. The experimental results have shown that when the molar ratio of ChCl, glycerol, and l -arginine was 1:2:0.1, DOF was the major product with a yield of 22.6% at 90 °C for 120 min. The chemical shift titration indicated that the carboxyl group of l -arginine in the TDES is the catalytical active site, so the mechanism of the catalytic reaction between GlcNH 2 and the TDES was proposed. Moreover, a reaction intermediate, dihydrofructosazine, was identified in the self-condensation reaction of GlcNH 2 by an in situ 1 H NMR technique.
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Journal of Physical Chemistry C
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2019
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IF 4.309
Qinghua Deng,Yun Xu,Ziqun Wang,Tifang Miao,Xianliang Fu,Liancai Xu
The development of new catalysts based on nonprecious metals for photocatalytic H2 evolution reaction (HER) is a very challenging endeavor. In this work, we used density functional theory (DFT) to design a high performance photocatalyst based on CoIII(dmgH)2pyCl. The sample was then prepared and used for photocatalytic HER under visible light irradiation with Eosin-Y (EY2–) and triethanolamine (TEOA) as a photosensitizer and electron donor, respectively. The feasibility and rationality of the DFT design were verified by the consistency between the photocatalytic performances and the theoretical results. The developed catalyst even showed the capability of splitting of water for H2 evolution. As for the most promising CoIII(dmgH)2(pyrazine)Cl, 1356 μmol of H2 can be produced over 25 mg of catalyst after irradiation for 3 h. The deactivation and the mechanism for the evolution of H2 over the sample were further investigated. We believe that this study provides an effective strategy for the design of highly efficient photocatalysts for HER.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
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IF 3.375
Yan Zhang,Zhonghang Chen,Xing Liu,Ze Dong,Peixin Zhang,Jun Wang,Qiang Deng,Zheling Zeng,Shuhua Zhang,Shuguang Deng
Removal of trace SO2 contaminants from gas mixtures by the molecular sieving effect is highly desired. Herein, a microporous metal–organic framework Cu2(pzdc)2(pyz) [CPL-1, pzdc = 2,3-pyrazinedicarboxylate; pyz = pyrazine] with a dumbbell-shaped 1D channel and specific binding sites is explored for deep desulfurization. The proper size of 4.1 × 6.2 Å and strong SO2 trapping sites on CPL-1 render a high adsorption uptake of SO2 (44.8 cm3 g–1) with a record-high selectivity for SO2/N2 (368) and SO2/CH4 (74.3) separation under ambient conditions. Moreover, the dispersion-corrected density functional theory calculations have identified the dual specific adsorption sites of SO2, such as Sδ+···Oδ− electrostatic interactions and Oδ−···Hδ+ hydrogen bonds. The feasibility of CPL-1 for SO2/N2, SO2/CH4, CO2/CH4, CO2/N2, and mimicked flue gas mixture separations was validated by dynamic breakthrough experiments. Water vapor and CO2 impurity were introduced to the gas feed streams to confirm the excellent separation performance of CPL-1. Moreover, a scale-up production of CPL-1 via a facile and green method was conducted, and a reproducible CPL-1 adsorbent with undamaged adsorption and separation performances was successfully manufactured in kilogram quantity. These unique features render CPL-1 a very promising adsorbent for practical desulfurization processes.
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JOURNAL OF SOLID STATE CHEMISTRY
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2018
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IF 2.179
Shi-Yuan Zhang,Yuan-Yuan Yang,Yue-Qing Zheng,Hong-Lin Zhu
Electrocatalytic reduction of CO 2 to useful fuels or chemicals is a promising path for carbon recycling. In this study, a novel mixed-metallic MOF [Ag 4 Co 2 (pyz)PDC 4 ][Ag 2 Co(pyz) 2 PDC 2 ] was synthesized, and it transformed into Ag doped Co 3 O 4 catalyst, which exhibits excellent electro-catalytic performance for reduction of CO 2 in water to syngas (H 2 + CO). The as-prepared Ag/Co 3 O 4 material exhibits a high selectivity of CO in 0.1 M KHCO 3 aqueous solution (CO 2 saturated) with the corresponding faradaic efficiency up to 55.6%. Compared with the Ag/Co 3 O 4 electrode, the maximum faradaic efficiency (FE) of CO of pure Co 3 O 4 is 21.3% at − 1.8 V vs. SCE. The results show that the presence of Ag can improve the efficiency of CO significantly, thereby inhibiting the production of H 2 . The stability of the samples can be maintained for more than 10 h at − 1.8 V vs. SCE. The ratio of production between H 2 and CO can be controlled by varying the potential values.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2018
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IF 3.412
Yu Zhang,Yuping Liu,Wenxi Yang,Jia Huang,Yingqiao Liu,Mingquan Huang,Baoguo Sun,Changlin Li
To characterize potent odor-active compounds in preserved egg yolk (PEY), volatile compounds were isolated by headspace solid-phase microextraction and solvent-assisted flavor evaporation. Gas chromatography–olfactometry (GC–O) and gas chromatography–mass spectrometry (GC–MS) analyses identified a total of 53 odor-active compounds by comparing the odor characteristics, MS data, and retention indices with those of reference compounds. Twenty-seven odorants were detected in at least five isolates that were extracted and analyzed by the same method, and their flavor dilution (FD) factors, ranging from 1 to 2048, were measured by aroma extract dilution analysis (AEDA). To further determine their contribution to the overall aroma profile of PEY, 22 odorants with FD factors ≥16 and GC–MS responses were quantitated, and their odor activity values (OAVs) were calculated. According to the OAV results, 19 odorants with OAVs ≥ 1 are the potent odorants that greatly contribute to the characteristic aroma of PEY. Nine compounds were identified for the first time: (E,Z)-2,6-nonadienal, (E)-2-nonenal, 2-methylbutanal, dimethyl disulfide, trimethylamine, methional, dimethyl trisulfide, diisopropyl disulfide, and diethyl disulfide.
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