RSC Advances
·
2017
·Vol. 7
·期 61
·38691-38698
·
IF 3.108
Bin Li,Wubin Wu,Tianyong Zhang,Shuang Jiang,Xingwei Chen,Guanghui Zhang,Xia Zhang
UiO-66 with high dispersibility and a cuboctahedron morphology was synthesized by an improved solvothermal method. The morphology of UiO-66 was adjusted using benzoic acid as a modulator. UiO-66 with a regular morphology was then used as the support to load ferrocene (Fc). A series of Fc@UiO-66 composites were prepared via a facile impregnation method. The composites were characterized by powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM/EDX mapping, FT-IR, UV/vis, TG analysis, N2 adsorption–desorption, and X-ray photoelectron spectroscopy (XPS). The results showed that Fc was incorporated into UiO-66, thus preventing the agglomeration of Fc particles in water. The Fc@UiO-66 composites with a Fc loading of 5% (FU-5) exhibited the highest catalytic activity for hydroxylation of phenol with H2O2 at room temperature in water, which gave a phenol conversion of 38.5% and 87.4% selectivity for dihydroxybenzenes (DHB). UiO-66 played a crucial role in the enhancement of catalytic performance compared with conventional supports such as γ-Al2O3, etc. A hydroxyl radical mechanism was proposed for this catalytic hydroxylation process and the high selectivity was attributed to the interaction between Fc particles and UiO-66.
研究领域:
化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Yixiong Wu,Yanqi Xu,Cunjun Li,Hai Wang,Xinyu Wang,Aimiao Qin,Haiqing Qin,Linjiang Wang
One-step selectively photocatalytic phenol hydroxylation to produce Dihydroxybenzenes (DHB) is an attractive and challenging strategy. However, the rapid recombination of photogenerated carriers existed in single component photocatalyst seriously hinders the photocatalytic efficiency. The heterojunction strategy can optimize the band structure of the photocatalyst, and effectively improve the carriers' separation and transfer during the photocatalytic process. Herein, we successfully designed and prepared a 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure photocatalyst by coupling TiO 2 nanorods with Ni 3 Fe 1 -LDH nanosheets for the photocatalytic phenol hydroxylation to produce DHB. The results showed that the 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure had a suitable energy band structure for the photocatalytic phenol hydroxylation and the heterostructure accelerated the carriers’ separation and transfer. Meanwhile, the high porosity and abundant active sites were conducive to the adsorption of H 2 O 2 and the photogenerated carriers transfer efficiency from the photocatalyst to H 2 O 2 . The 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure showed excellent photocatalytic performance of phenol hydroxylation, where the phenol conversion was 48.6%, and the selectivity of DHB was 81.1% at 25 °C and 4 h of light illumination. Furthermore, the as-prepared photocatalysts exhibited good stability after four cycles of experiment. This work provided a convenient and efficient method for the green synthesis of DHB.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOILS AND SEDIMENTS
·
2023
·Vol. 23
·期 6
·2473-2481
·
IF 3.6
Li Ke-wei,Lu Hai-long,Nkoh Nkoh Jackson,Xu Ren-kou
Purpose Phyllosilicate minerals are the important components in soils and an important source of activated aluminum (Al) during soil acidification. However, the mechanisms for Al activation in phyllosilicate minerals were not understood well. This study was designed to investigate the role of hydroxyl groups on the surface of montmorillonite in acidification-induced activation of solid aluminum. Materials and methods Montmorillonite was treated at high temperatures to remove the hydroxyl groups from its surface, and then XRD, FTIR, and 27 Al NMR of montmorillonite before and after high-temperature treatment were determined. After that, Al activation during acidification of montmorillonite treated at different temperatures was investigated using the constant pH titration method. Results and discussion The results showed that hydroxyl groups on the surface of montmorillonite can effectively be removed when the temperature was raised to 670 °C. After high-temperature treatment, the crystallinity of the montmorillonite was reduced. The montmorillonite layer space was reduced, the pH and cation exchange capacity (CEC) of the mineral were decreased, and consequently the amount of acid consumed during acidification was significantly reduced. The decrease of CEC and surface hydroxyl groups in the mineral was responsible for the reduction in acid consumption during mineral acidification. After high-temperature treatment, the Al coordination structure of montmorillonite was transformed from six-coordination to four-coordination. The removal of surface hydroxyl groups inhibited the activation of Al during montmorillonite acidification, and the inhibition effect was increased with increasing temperatures below the complete dehydroxylation point. Conclusions The activation of Al during montmorillonite acidification was inhibited, suggesting that the hydroxyl groups at the edge of montmorillonite played an important role in Al activation process.
研究领域:
土壤学
·
矿物学
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 15
·e202300287
·
IF 2.1
Mengyu Liu,Xiang Yu,Lanting Yang,Guangzai Nong
Graphical In this study, copper-ammonia complexes were utilized as catalysts for the polymerization of hydroquinone. These complexes not only acted as catalysts, but also bound to the poly(hydroquinone) during the polymerization process. With acid hydrolysis to remove the complexes, a thermally stable poly(hydroquinone was obtained with a degree of polymerization of 2–9 and yield of 63.2 %. The copper-ammonia complexes also accelerated the polymerization rate by three times compared to using only ammonia solution, offering potential for improving hydroquinone polymerization efficiency. Poly(hydroquinone) (PHQ) is a class of polymers with a leading chain composed entirely of quinone-phenol structures, which possess both the heat resistance of polymers and the redox activity of the monomer quinone-phenol and have promising applications in sensors, anti-corrosion and antioxidants. However, the current synthesis efficiency is low, and the product solubility is poor, which hinders its wide application. In this paper, the copper-ammonia complex was used to catalyze the polymerization of hydroquinone. The product‘s structure was verified by FTIR, UV-Vis, XPS, SSNMR and EDS. The degree of PHQ obtained by GPC was 2–9, and the reaction mechanism of the polymerization process was demonstrated in detail. The experiments showed that the copper-ammonia complex not only acted as a catalyst but also participated in the reaction, firstly generating the PHQ copper-ammonia complex, which is almost insoluble in water and common organic solvents. Then by further acid washing to dislodge the copper-amino groups, the resulting PHQ was able to dissolve in solvents such as DMSO and methanol. In addition, the method is three times faster than the catalytic rate using an equivalent amount of ammonia.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2013
·Vol. 2013
·期 32
·7411-7420
·
IF 3.344
Zhengkai Chen,Weijun Yang,Lijun Xu,Lili Zhang,Maozhong Miao,Hongjun Ren
Graphical Highly substituted 2-hydroxyflavanones can be obtained through a tandem O -arylation/hydroxylation process from triazenylaryl-substituted diketones in the presence of a Lewis acid. A transition-metal-free tandem O -arylation/hydroxylation approach has been developed for the efficient synthesis of highly substituted 2-hydroxyflavanones from triazenylaryl-substituted diketones. The intermediate benzopyrylium cation may be involved in these reactions.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
APPLIED ENERGY
·
2018
·
IF 7.9
Yuan Zhang,Yong Wang,Hongyou Cui,Pingping Zhao,Feng Song,Xiuyu Sun,Yujiao Xie,Weiming Yi,Lihong Wang
Conversion of the carboxylic acids in bio-oil into ketones via decarboxylation is a highly efficient approach for bio-oil upgrading. However, the char formation during decarboxylation is due to the existence of a considerable amount of pyrolytic sugars in bio-oil, which severely weakens the upgraded bio-oil yield and the energy efficiency. In this paper, two pretreatment approaches, hydrolysis and oxidative hydrolysis, were employed to solve this problem. The pyrolytic sugars in bio-oil were firstly enriched into the water-soluble fraction through water extraction, followed by hydrolysis or oxidative hydrolysis pretreatment before decarboxylation. With the aid of hydrolysis pretreatment, the upgraded bio-oil yield was increased from 27.55 to 30.74%, and the energy efficiency was increased from 77.59 to 88.67% after decarboxylation, whereas the char yield was decreased from 5.67 to 3.81% in comparison with the results without hydrolysis. In the case of oxidative hydrolysis pretreatment, the upgraded bio-oil yield and the energy efficiency were further enhanced to be 32.68% and 92.70% respectively, while the char yield was drastically decreased to only 1.15%. To clarify the effect of the pretreatment, two pentoses and four hexoses were used to investigate the reaction pathways for their conversion in the water-soluble fraction during hydrolysis or oxidative hydrolysis pretreatment. The experimental results showed that hydrolysis of the water-soluble fraction could effectively convert pyrolytic sugars to carboxylic acids. In contrast, oxidative hydrolysis could convert not only the pyrolytic sugars, but also most of the aldehydes and ketones in the water-soluble fraction into carboxylic acids. The reaction pathways for conversion of pentose and hexose into organic acids via oxidative hydrolysis were also investigated.
研究领域:
生物质能
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化学工程
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2017
·Vol. 40
·期 6
·901-910
·
IF 1.87
Zhang Qiang,Gong Jin-Song,Dong Ting-Ting,Liu Ting-Ting,Li Heng,Dou Wen-Fang,Lu Zhen-Ming,Shi Jin-Song,Xu Zheng-Hong
3-Hydroxypropionic acid (3-HP) is an important platform chemical in organic synthesis. Traditionally, 3-HP was produced by chemical methods and fermentation process. In this work, a novel enzymatic method was developed for green synthesis of 3-HP. A yeast strain harboring nitrile-hydrolyzing enzyme was newly isolated from environmental samples using 3-hydroxypropionitrile (3-HPN) as the sole nitrogen source. It was identified to be Meyerozyma guilliermondii CGMCC12935 by sequencing of the 18S ribosomal DNA and internal transcribed spacer, together with analysis of the morphology characteristics. The catalytic properties of M. guilliermondii CGMCC12935 resting cells were determined, and the optimum activity was achieved at 55 °C and pH 7.5. The enzyme showed broad substrate specificity towards nitriles, especially 3-HPN, aminoacetonitrile and 3-cyanopyridine. The presence of Ag + , Pb 2+ and excess substrate inhibited the enzyme activity, whereas 5% (v/v) ethyl acetate had a positive effect on the enzyme activity. M. guilliermondii CGMCC12935 resting cells by addition of 3% glucose could thoroughly hydrolyze 500 mM 3-HPN into 3-HP within 100 h and the maximal accumulative production of 3-HP reached 216.33 mM, which was over twofolds than the control group with no additional glucose. And this work would lay the foundation for biological production of 3-HP in industry.
研究领域:
生物化学
·
工业微生物学
✓ 已验证
DOI
PubMed
高影响因子
Polymer Chemistry
·
2020
·Vol. 11
·期 34
·5512-5525
·
IF 5.342
Ming Zhang,Yifei Tu,Zibo Zhou,Guozhang Wu
The exo-hydroxyl group (exo-OH) on isosorbide (ISB) has long been asserted as a highly reactive moiety compared with the endo-hydroxyl group (endo-OH). In this study, calculations based on density functional theory and experiments without adding catalysts reveal that endo-OH has strong nucleophilic ability, and in the case of transesterification with diphenyl carbonate, the nucleophilic attack surmounts steric hindrance in rendering endo-OH more reactive than exo-OH. The kinetics of transesterification with different catalysts is investigated to determine the catalytic reactivity and molecular structure evolution. The results show that preferential activation of exo-OH moieties can be achieved either by reducing the coordination ability of catalytic cations (lg β1) or by enhancing the alkalinity of catalytic anions. Despite the low reactivity of exo-OH on ISB monomers, terminal exo-OH on carbonate oligomers exhibits higher reactivity than terminal endo-OH, justifying the experimental fact that ISB-based polycarbonates (ISB-PCs) are mostly terminated by endo-OH. Balancing the reactivity between endo-OH and exo-OH can be promoted by increasing the reaction temperature, thus accelerating transesterification to a high equilibrium constant. These findings help to clarify the mechanism of ISB transesterification and provide new strategies for the synthesis of high-molecular-weight ISB-PCs.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Qi Li,Jie Ren,Ying-juan Hao,Yi-lei Li,Xiao-jing Wang,Ying Liu,Ran Su,Fa-tang Li
Hydroxyl radicals always play important role in the photocatalytic degradation of pollutants and thus lots of efforts have been made to enlarge their amount. Herein, BiOCl photocatalysts with different surface hydroxyl groups amount are synthesized using ionic liquid self-combustion (C-BiOCl) and hydrothermal method (H-BiOCl) to deep understand the roles of hydroxyl radicals in toluene mineralization. It is found that hydroxyl radicals in H-BiOCl have reverse inhibitory effect on the ring-opening reaction in the photocatalytic mineralization process of toluene and C-BiOCl exhibits more excellent ability and stability in mineralizing toluene. The reason is that C-BiOCl lacking hydroxyl groups can selectively generate benzoic acid by holes and superoxide anion radicals; while H-BiOCl with large number of hydroxyl groups will lead to the production of hydroxyl radicals and phenolic intermediates, which will preferentially cover active sites such as oxygen vacancies, thereby reducing the performance and stability of the catalyst.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Xingyun Hu,Xianjia Peng,Linghao Kong,Feng Zhu
The most toxic and mobile form of vanadium (V) is V(V). Thus, the oxidation of V is a subject of considerable importance since the process may increase environmental risks of V. V(IV) is known to be stable when pH < 4.5. However, in this study, stable V(IV) was oxidized almost completely in goethite suspension within 60 min at pH 2.0 and pH 4.0, correspondingly, only 25%–30% and 15%–20% of V(IV) were oxidized in equimolar Fe 3+ solution and the blank solution, respectively. The promoted oxidation of V(IV) by FeOOH is attributed to the formation of the complex, VO(OFe<) + or VO(OFe<) 2 . On the one hand, the formation of the complex caused higher pH in the interface of solid FeOOH and corresponding lower conditional potential of V(V)/V(IV) than those in bulk solutions, which facilitates the oxidation of V(IV). On the other hand, the surface group OFe < may serve as a medium that facilitating the electron transfer from V(IV) ions to dissolved oxygen molecules, also favoring the oxidation of V(IV). This study not only deepens our understanding of the transfer, transformation, and risk of V in environments, but also provides a reference to speculate the fate of similar elements in environments.
研究领域:
环境化学
·
地球化学
·
水污染控制
·
金属形态转化
·
界面过程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Dun Fu,Tonni Agustiono Kurniawan,Heng Li,Liuying Wang,Zheng Chen,Wen Li,Yuanpeng Wang,Haitao Wang,Qingbiao Li
The technical applicability of hydrochar-derived pyrolysis char-supported Cu nanoparticles composite (Cu NPs/HDPC) to the degradation of octocrylene (OC) was investigated in aqueous solutions in the presence of H 2 O 2 . The physico-chemical properties of the Cu NPs/HDPC composite before and after degradation reaction were described. The role of OH in this H 2 O 2 -led degradation was examined using electron spin resonance (EPR) technique. The possible degradation mechanisms of OC by the Cu NPs/HDPC-H 2 O 2 system and its degradation pathways were investigated. A relatively large surface area and pore volume of the HDPC (191.4 m 2 g −1 and 0.11 cm 3 g −1 , respectively) resulted in well-dispersed Cu NPs loading on the surface. The degradation efficiency of OC (50 μM) was 97.0% in the presence of Cu NPs/HDPC composite (0.5 g L −1 ) and H 2 O 2 (20 mM) at pH 5.6 in 4 h, which was significantly higher than in Cu NPs/biochar and the integrated HDPC-Cu NPs, i.e., 62.4% and 79.7%, respectively, under the same conditions (ANOVA test; p ≤ 0.05). Several oxidation by-products of the OC included benzophenone, 3,3-diphenylacrylonitrile, and others. The OH, which resulted from the Fenton-like oxidation between the Cu species and H 2 O 2 on the HDPC surface, was the predominant factor responsible for the OC degradation in the solution. The OH formation was facilitated by a single-electron transfer process from the HDPC surface, in which the Cu NPs/HDPC composite with its C OH functional group promoted the decomposition of H 2 O 2 . These findings contribute to a novel approach of cost-effective wastewater treatment by adding value to unused waste materials from agricultural industries.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Science China-Chemistry
·
2021
·Vol. 64
·期 5
·770-777
·
IF 9.445
Qiao Xiaofeng,Lin Yuhan,Li Jiazhen,Ma Wanhong,Zhao Jincai
Both β- and γ- hydroxyketone structures are important units in biologically active molecules, synthetic drugs and fine chemicals. Although there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s), the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp 3 ) positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation of three inert C-H σ bonds all at once. Here, we show that a TiO 2 -CH 3 CN photocatalytic suspension system enables the insertion of dioxygen into one C(sp 3 )-C(sp 3 ) bond of strained cycloparaffin derivatives, by which difunctionalized hydroxyketone products are obtained in a one-pot reaction. With the cleavage event to release strain as the directional driving force, as-designed photocatalytic reaction systems show 21 examples of β-hydroxyketone products with 31%–76% isolated yields for three-membered ring derivatives and 5 examples of γ-hydroxyketone products with 30%–63% isolated yields for four-membered ring substrates. 18 O isotopic labeling experiments using 18 O 2 , Ti 18 O 2 and intentionally added H 2 18 O, respectively, indicated that both oxygen atoms of hydroxyketone products were exclusively from dioxygen, suggesting a previously unknown H + /TiO 2 -e − catalyzed arrangement pathway of the hydroperoxide intermediate to convert dioxygen into hydroxyketone units.
研究领域:
有机化学
·
光催化化学
·
药物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）