JOURNAL OF CATALYSIS
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2022
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IF 8.047
Chenghao Zhang,Mengmeng Huang,Jiabin Yin,Fengyan Lou,Xingkun Chen,Jisong Zhang
The development of robust heterogeneous catalysts that can realize the aerobic oxidation of alcohols in metal-free conditions is a profound challenge. Here, we report a reliable methodology to covalently graft 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) moieties on commercial activated carbons. Catalyst activity and stability are investigated in a continuous micro-packed bed. Notably, the catalytic activity achieved in the aerobic oxidation of benzyl alcohol to benzaldehyde (Turnover frequency: 135.9 h −1 , Turnover number: 328.9) is superior to the catalysts reported in the literature (Turnover frequency: 0.5–67 h −1 ) and the state-of-art commercial catalysts (Turnover number: 205.6). Additionally, the influence of H 2 O on the benzaldehyde yield indicated that H 2 O as the only by-product plays a promotional role in TEMPO/TBN catalytic system. Based on these results and previous mechanism analysis, a possible reaction mechanism is proposed. Post-catalytic analysis and regeneration strategy indicated that the cleavage of the amide bond linkages is the main reason for catalyst deactivation.
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RAPID COMMUNICATIONS IN MASS SPECTROMETRY
·
2022
·Vol. 36
·期 21
·e9381
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IF 2.586
Baocheng Ji,Yu Han,Wenhao Zhao,Lanrui Yang,Xu Xu,Yanhong Bai
Rationale Various solvent supports have been developed to overcome solvent instability during liquid-phase microextraction. The hydrophobic polyurethane sponge (PS) possesses numerous cross-linked internal microchannels and terminal micropores that can facilitate steady solvent storage capacity, high extraction efficiency, extractant loading, and recycling convenience. Methods In this study, an easy, convenient, and efficient PS-supported liquid-phase microextraction (PS-LPME) coupled with gas chromatography–mass spectrometry (GC–MS) method was developed for the trace analysis of different organic compounds in aqueous solutions. Different extraction solvents, PS dosages, stirring speeds, and extraction times were first investigated by extracting eight polycyclic aromatic hydrocarbons (PAHs: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene), and then applied for the analysis of triazines, amides, chloroacetamides, and organophosphorus compounds. Results High enrichment factors (approximately 208–439) were observed for the monitored PAHs. Good linearities, with determination coefficients ( r 2 ) greater than 0.9992, were achieved in the concentration range of 0.01–50 μg L −1 . Low limits of detection and quantification were found in the ranges of 0.3–3 ng L −1 and 1–10 ng L −1 , respectively. At three spiked concentrations (0.1, 1, and 10 μg L −1 ), good recoveries were obtained in the range of 91.6–118.5% with intra- and inter-day relative standard deviations of less than 6.4% and 11.7%, respectively. Conclusions The developed PS-LPME method coupled with GC–MS was successfully applied in the analysis of different organic compounds in aqueous solutions and has shown great convenience and satisfactory enrichment performance in microextraction analysis.
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Food Chemistry-X
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2022
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IF 6.443
Pengkai Wang,Jingna Liu,Yuanhong Zhuang,Peng Fei
Aimed at exploring the impact of fatty acid side chains on the anthocyanins, n- valeric acid, n- decanoic acid and myristic acid were used to grafting onto the blueberry anthocyanins, and the acylating degree value of the of n -valeric acid acylated anthocyanins (Va-An), n -decanoic acid acylated anthocyanins (De-An) and myristic acid acylated anthocyanins (My-An) reached 6.43 %, 7.56% and 8.38 %, respectively. After acylation modification, the octanol–water partition coefficient of the anthocyanins increased from −0.20 (native anthocyanins, Na-An) to 0.65 (Va-An), 0.66 (De-An) and 0.72 (My-An), respectively, indicating the increasement of the lipid solubility. Besides, although the DPPH clearance of acylated anthocyanins was lower than that of native anthocyanins, the inhibition ratio of β-carotene bleaching and malonaldehyde reduction effect of the acylated blueberry anthocyanins in Caenorhabditis elegans were both stronger than that of native anthocyanins, which might be caused by the improvement of lipid solubility of the anthocyanins.
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JOURNAL OF POROUS MATERIALS
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2022
·Vol. 29
·期 5
·1479-1487
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IF 2.523
Ye Tiantian,Liu Hanfang,Wang Fupeng,Xie Huijie,Ran Saisai,Xu Wei,Liu Jia,Li Bin,Lin Haifeng,Chai Yongming,Wang Lei
Here, we demonstrate a simple in situ synthesis of Pd@silicate-1 (S-1), using [Pd(NH 2 CH 2 CH 2 NH 2 ) 2 ]Cl 2 as a metal precursor and steam-assisted crystallization (SAC) method. The ultra-small Pd nanoparticles (NPs) (~ 1 nm) can be successfully in situ encapsulated into the silicate-1 matrix with well dispersion. The obtained Pd@S-1 catalyst possesses high crystallinity, a large specific surface area and pore volume. More importantly, Pd NPs encapsulated into silicate-1 matrix can avoid the aggregation and sintering during catalytic reaction. Meanwhile, micropores of silicate-1 can improve the selectivity of the products in the hydrogenation of biomass furfural. Consequently, Pd@S-1 catalyst shows excellent catalytic activity in the selective hydrogenation of biomass furfural with selectivity of 95.7% and activity of 83.7% in the condition of relatively low temperature (458 K). Therefore, this strategy provides a new idea for the synthesis of molecular sieve supported metal catalysts.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2022
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IF 3.269
Song Lin,Houchun Yan,Yueyang Jiang,Hongyue Guo,Yicong Zhao,Mai Han,Qingsong Li
The liquid–liquid equilibrium (LLE) data of water, 2,2,2-trifluoroethanol (TFE) and different solvents {1-hexanol, 1-pentanol, 1-octanol and 2-octyl alcohol} were measured at 303.2 K under 101.3 kPa. The distribution coefficient (D) and selectivity factor (S) were calculated, and the results showed that the four extractants had good separation effects. The experimental data were successfully correlated by the two thermodynamic models of NRTL and UNIQUAC. In addition, the binary interaction parameters were obtained. The root mean square deviation (RMSD) of the fitting results were all less than 0.6%. The GUI-MATLAB was used to verify the consistency of the binary interaction parameters calculated by the thermodynamic models.
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FUEL
·
2022
·
IF 8.035
Jinghua Wang,Jiangang Wang,Hongyou Cui,Zhihe Li,Ming Wang,Weiming Yi
Efficient esterification of biomass-derived levulinic acid (LA) to levulinate was investigated in molten salt hydrates (MSH) for the first time. A series of molten salt hydrates (LiBr·3H 2 O, LiCl·3H 2 O, ZnCl 2 ·3H 2 O, CaCl 2 ·3H 2 O and CaBr 2 ·3H 2 O) were examined in terms of their catalytic activity and Hammett acidity (H 0 ). Among them, CaBr 2 ·3H 2 O, ZnBr 2 ·3H 2 O and ZnCl 2 ·3H 2 O exhibited excellent activity. It was found that formic acid (FA), a compound that is cogenerated with LA in converting cellulose and hemicellulose as well as their derived sugars, can significantly enhance esterification of LA when reacting in MSHs. Mechanism analysis demonstrated that the promotion effect of FA on the formation of levulinate was resulted from transesterification of LA with butyl formate (BF). Under same conditions, as high as 99.8 % of butyl levulinate (BL) yield was obtained in CaCl 2 ·3H 2 O, while it was merely 19.6% in the absence of CaCl 2 ·3H 2 O. Hammett acidity measurement confirmed that CaCl 2 ·3H 2 O is able to promote the protonation of LA and FA, and thus accelerating the esterification and transesterification reactions. Besides, reacting in CaCl 2 ·3H 2 O can spontaneously form a biphasic reaction system: an organic phase that mainly consists of BL and n -butanol, and an aqueous phase composed of CaCl 2 , acids and water. Such a biphasic system help boost the esterification equilibrium and the subsequent separation and purification of the synthesized esters.
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Xiao Liang,Jiyizhe Zhang,Min Li,Kai Wang,Guangsheng Luo
Surfactant adsorption plays an important role in the microfluidic droplet formation process, which manifested as dynamic interfacial tension phenomenon. Due to rapid droplet expansion and convection flow around the droplet, traditional methods of interfacial tension measurement are difficult to investigate the surfactant adsorption kinetics in microfluidic process. We thus developed a differential pressure based microfluidic platform and proposed an in-situ method to determine time-evolving interfacial tension during microfluidic droplet formation according to Young-Laplace equation in this research. Four classical nonionic surfactants: Triton X-100, Tween 20, Brij 56, and Brij 58 were tested with classical n -octant/water as the working system. The concentrations of these surfactants at interface were further determined from the measured interfacial tension based on Frumkin adsorption model. The adsorption rates of surfactant showed that increasing surfactant concentration in the bulk solution and flow rate of continuous phase both promoted surfactant adsorption in the cases of Tween 20, Brij 56, and Brij 58, indicating the mass transfer-controlled mechanism of adsorption kinetics. The average thickness of mass transfer boundary layer ranged from 0.1 to 5 μm was determined from the mass transfer rate and a correlation equation was proposed to predict the thickness. However, the adsorption mechanism of Triton X-100 turned to be kinetics-controlled for its high critical micelle concentration, which helped to determine the adsorption and desorption rate constants.
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POLYMER
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2022
·
IF 4.432
Manman Zhao,Mingqiang Chen,Yakun Zong,Zhanxiong Li
In this paper, by means of carbene polymerization, low surface energy polymers were covalently grafted onto the surface of cotton fabric, which successfully constructed a rough morphology in-situ and provided excellent hydrophobic properties. Firstly, the grafting site was constructed on the surface of cotton fiber, and octyl diazoacetate was synthesized as a precursor and grafted onto cotton fiber. However, due to the soft side-chain grafted polymer was film-forming, the WCA of fabric grafted with octyl diazoacetate was only 124.0 ± 2.1°. In order to construct a roughening morphology in-situ, tert -butyl diazoacetate and phenyl diazoacetate was introduced and co-grafted with octyl diazoacetate. It was found that tert -butyl diazoacetate and phenyl diazoacetate were polymerized into spherical and cubic crystals on the surface of cotton fiber, respectively. These two precursors were co-grafted with octyl diazoacetate on the surface of cotton fiber to produce a rigid polymer chain and form roughening crystal morphology . The surface morphology of the treated fiber was tested by SEM, AFM and ImageJ, it was found that different morphologies could be formed on the fiber surface when octyl diazoacetate and tert -butyl diazoacetate were co-grafted with different molar ratios. Among them, when octyl diazoacetate/ tert -butyl diazoacetate(1:19)was used, the composite morphology of polymer film coated particles can be formed on the fiber surface, and the surface modification of “roughening” increased the WCA of the fabric to 143.2 ± 1.8°, which gave the fabric good hydrophobicity . When octyl diazoacetate was co-grafted with phenylethylcarbene diazoacetate at the molar ratio of 1:19, the surface of the treated fiber appeared film-like and microspheres embedded in the membrane. It is worth pointing out that the film-wrapped microsphere on the fiber surface provides a lotus leaf-like morphology. The WCA of the as-prepared fabric reached 151.2 ± 0.8° with excellent self-cleaning properties and super hydrophobicity.
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FOOD CHEMISTRY
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2022
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IF 9.231
Pimiao Huang,Zhirong Wang,Xiya Feng,Jianquan Kan
Phenolic compounds are effective means of promoting the release of fishy odor compounds, thereby significantly decreasing the fishy odor of fish products. In this study, the mechanisms underlying the promotion of fishy odor release by three phenolic compounds, rosmarinic acid (RA), carnosic acid (CA), and carnosol (CS), through interactions with the myofibrillar protein (MP) of silver carp were investigated. The addition of phenolic compounds (5, 25 and 125 μmol/g protein) was found to significantly alter the conformation of MP and decrease the fishy odor compound binding sites through the formation of phenolic compound-protein complexes. Of note, both sensory evaluation and gas chromatography analysis revealed a significant facilitation of fishy odor compound release by phenolic compounds in the presence of MP. In MP treated with 125 μmol/g protein of RA, the contents of fishy odor compounds increased from 30% to- 37%, with an increase of fishy odor score of 58%, compared to the un-treated control. Similar changes were observed when treating MP with CA or CS. These changes were likely due to the enhancement of protein–protein interactions caused by phenolic compounds and competition between fishy odor and phenolic compounds for hydrophobic binding sites in MP. The release of fishy odor compounds increased as the amount of phenolic compounds utilized increased with RA being the strongest promoter of fishy odor compounds, followed by CA and CS.
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JOURNAL OF BIOMATERIALS APPLICATIONS
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2022
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IF 2.712
Zao Cheng,Junfei Gao,Qianqian Liu,Qun Gu
This work describes the relationship between the antibacterial activity and the ester chain length (C1-C8) of (R)-3-Hydroxybutyric ((R)-3-HB) alkyl esters that synthesized from (R)-3-HB acid ((R)-3-HBA) by esterification reaction. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) decrease as the length of the (R)-3-HB alkyl ester chain increases from 1 to 6, but (R)-3-HB-C7 and (R)-3-HB-C8 have their own rules for different microorganisms. Among them, the (R)-3HB-C6 has the relatively best antibacterial and antifungal properties, which MIC were 1.95 mg mL−1 against E. coli and S. aureus; 0.98 mg mL−1 against C. albicans and B. subtilis; 0.49 mg mL−1 against A. niger. Finally, the antimicrobial mechanisms of the (R)-3HB-C6 are revealed, and these include disruption of biofilm and the bacterial wall/membrane, leakage of the intracellular content, and change in the transmembrane potential. These results imply the potential application of (R)-3-HB alkyl ester as new antimicrobial agents; future research can use this as an antibacterial element to synthesize new polymer materials or agents with high-efficiency antibacterial activity.
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MICROCHEMICAL JOURNAL
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2022
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IF 5.304
Meichao Liao,Yang Zhao,Xiaoyue Yang,Lin Yang,E-Hu Liu,Bin Lu,Jiye Wang,Xiaopeng Liu,Yanzhong Chang,Li Duan
The green and efficient extraction of bioactive compounds from plant biomass is an extraordinary area of interest in the pharmaceutical industries. In a perspective of sustainable development, we investigate an eco-friendly route using recycle hydrophobic deep eutectic solvent-assisted water extraction (RHD-WE) to effectively and simultaneously extract five main phenolic acids (caftaric acid, chlorogenic acid, caffeic acid, cichoric acid, 3,5-di-O-caffeoylquinic acid) from medicinal plant. In the procedure, 20 mg Taraxacum mongolicum powder was mixed with 800 µL water and 200 µL camphor/p-chlorophenol-based hydrophobic deep eutectic solvent (DES) at a molar ratio of 1:3. After 10 min vortex and centrifugation, the mixture was separated into aqueous phase and DES phase. Compared with other published procedures, phenolic acids were enriched in the aqueous phase. Aqueous solution of phenolic acid could be directly used as raw materials without further purification in pharmaceutical industries. Besides, hydrophobic DES phase could easily be recovered and reused in recycling studies. This is the first study of the recyclability of hydrophobic DES. Generally speaking, the model for the extraction of phenolic acids was well established and verified. The extraction efficiency was higher than other traditional extraction methods, approximately 14 mg/g of phenolic acids were obtained in the aqueous phase. In addition, the extraction mechanism was preliminarily discussed in this research. Such novel RHD-WE method might improve the existing schemes for extraction of bioactive compounds from plant materials. This study suggested that hydrophobic DESs could be used as green and safe auxiliary extractant for pharmaceutical applications.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Yao Jin,Chao Li,Ning Zhang,Yaoxing Li,Kai Han,Shaofeng Song,Mingwang Pan,Zhicheng Pan
While waterborne polyurethanes (WPUs) have been applied to a broad range of fields, poor hydrophobic, water-resistant, and mechanical properties still limit their further development. Herein, we report a novel WPUs by an elaborate molecular design that 1 H,1 H,2 H,2 H,3 H,3 H-tridecafluoro-1-nonanol (TFN) was used as a capping agent at the end of the polyurethane chain, and polydimethylsiloxane (PDMS) used as a soft segment in the middle of the chain to synergistically enhance its properties. The TFN at the end of the polyurethane chain broke through the chain movement limitation, largely improving the surface hydrophobicity of coating, realizing the change from hydrophilic to hydrophobic with the water contact angles increased from 88.5° to 128.6°. PDMS as the soft segment increased the phase separation of polyurethane due to the thermodynamic immiscibility, improving the mechanical properties without sacrificing the hydrophobicity. Meanwhile, the water-resistant performance was also improved with the incorporation of PDMS. As a result, the hydrophobicity, water-resistance, and mechanical properties of as-synthesized WPUs coating can be improved simultaneously through the sophisticated molecular design, thus offering the potential to expand their applications.
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危险品化学品经营许可证（带存储）