Green Energy & Environment
·
2020
·
IF 6.395
Zhaoning Song,Juncong Yuan,Zhenping Cai,Dong Lin,Xiang Feng,Nan Sheng,Yibin Liu,Xiaobo Chen,Xin Jin,De Chen,Chaohe Yang
The advocacy of green chemical industry has led to the development of highly efficient catalysts for direct gas-phase propene epoxidation with green, sustainable and simple essence. The S-1/TS-1@dendritic-SiO 2 material with three-layer core–shell structure was developed and used as the support for Au catalysts, which showed simultaneously fantastic PO formation rate, PO selectivity and stability (over 100 h) for propene epoxidation with H 2 and O 2 . It is found that silicalite-1 (S-1) core and the middle thin layer of TS-1 offer great mass transfer ability, which could be responsible for the excellent stability. The designed dendritic SiO 2 shell covers part of the acid sites on the external surface of TS-1, inhibiting the side reactions and improving the PO selectivity. Furthermore, three kinds of SiO 2 shell morphologies (i.e., dendritic, net, mesoporous shell) were designed, and relationship between shell morphology and catalytic performance was elucidated. The results in this paper harbour tremendous guiding significance for the design of highly efficient epoxidation catalysts.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Pei Li,Bianfang Shi,Junyao Shen,Ran Cui,Wenze Guo,Ling Zhao,Zhenhao Xi
The amino-functionalization of TS-1 zeolite followed by immobilization of phosphotungstic acid (HPW) was presented to prepare a strong solid acid catalyst for the synthesis of bio-based tributyl citrate from the esterification of citric acid and n -butanol. γ-Aminopropyltriethoxysilane (APTES) was first grafted on the TS-1 zeolite via the condensation reactions with surface hydroxyl groups, and subsequently the HPW was immobilized via the reaction between the amino groups and the protons from HPW forming strong ionic bonding. The Keggin structure of HPW and MFI topology of TS-1 zeolite were well maintained after the modifications. The amino-functionalization generated abundant uniformly distributed active sites on TS-1 for HPW immobilization, which promoted the dispersity, abundance, as well as the stability of the acid sites. The tetrahedrally coordinated framework titanium and non-framework titania behaved as weak Lewis acid sites, and the protons from the immobilized HPW acted as the moderate or strong Brønsted acid sites. An optimized TBC yield of 96.2%(mol) with a conversion of -COOH of 98.1%(mol) was achieved at 150 °C for 6 h over the HPW immobilized on amino-functionalized TS-1. The catalyst exhibited good stability after four consecutive reaction runs, where the activity levelled off at still a relatively high level after somewhat deactivation possibly caused by the leaching of a small portion of weakly anchored APTES or HPW.
研究领域:
催化化学
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材料科学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2024
·
IF 3.5
Ze Zong,Xuliang Deng,Dong Lin,Yang Xu,Qiuming He,Zhe Ma,De Chen,Chaohe Yang,Xiang Feng
Titanosilicate with H 2 O 2 stands out as a highly consequential oxidized catalytic system, prized for its user-friendly operation, mild conditions, and eco-friendly attributes. However, a synthesis strategy for large surface area titanosilicalites approaching the theoretical lowest Si/Ti ratio without extra-framework Ti species remains an ongoing challenge. In this study, we successfully synthesized single-crystalline Ti-rich nanosized aggregated TS-1 by shielding effect with a Si/Ti polymer. This polymer demonstrated effectiveness in restraining TiO 2 species by regulating the proximity of Si/Ti species in Ti-Diol-Si polymers. The polymer not only facilitated the synthesis of single-crystalline Ti-rich TS-1 but also exploited the chain length of PEG, functioning as a shielding cage by hydrogen bonds, to synthesize nanosized aggregated TS-1 (TS-1-PEG400). This TS-1-PEG400 exhibited superior conversion (~60%), selectivity (~90%), and stability in 1-hexene epoxidation. This study not only establishes a synthesis pathway for Ti-rich TS-1 but also holds the potential to enhance related industrial oxidation reactions involving titanosilicates and H 2 O 2 .
研究领域:
催化
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材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
FOOD SCIENCE AND BIOTECHNOLOGY
·
2016
·Vol. 25
·期 1
·221-227
·
IF 0.699
Zhu Ming-Ming,Wang Shu-Lin,Fan Ming-Tao,Li Jing
Reactions of a crude enzyme extracted from S. pasteuri TS-82 to cleave carbon-carbon bonds in bicyclic and monocyclic carotenoid substrates were investigated. Dependencies of enzyme activities on processing temperature and pH were investigated and non-volatile and volatile breakdown products were characterized. The crude enzyme showed a maximum activity with zeaxanthin, followed in decreasing order by β-carotene, canthaxanthin, astaxanthin, and β-apo-8'-carotenal. The optimum pH value of the enzyme was 3.0 for both bicyclic and monocyclic substrates, whereas the optimum temperature of the enzyme was substrate specific at 60°C for C 40 carotenoids and 50°C for β-apo-8'-carotenal. Liquid Chromatography-Mass Spectra (LC-MS) and Gas Chromatography- Mass Spectra (GC-MS) indicated that the crude enzyme was able to catalyze substrates with cleavage at 9-10 and 9'-10' double bonds with C 13 norisoprenoids being the main volatile reaction products in each case. Astaxanthin is a major source for α,β-dihydro-β-ionone.
研究领域:
生物化学
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食品科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers of Chemical Science and Engineering
·
2023
·Vol. 17
·期 6
·772-783
·
IF 4.5
Gao Xiu,Luo Beining,Hong Yanping,He Peihang,Zhang Zedong,Wu Guoqiang
Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 µm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 12
·939
·
IF 3.8
Yuting Sun,Xinyu Chang,Junling Zhan,Chongyao Bi,Zhehan Dong,Shuaishuai Sun,Mingjun Jia
To synthesize high-quality TS-1 zeolites with enhanced catalytic performance for 1-hexene epoxidation is highly attractive for meeting the increased need for sustainable chemistry. Herein, we report that a series of framework Ti-enriched TS-1 zeolites with high crystallinity can be effectively synthesized by the hydrothermal crystallization of a composite precursor composed of diol-based polymer (containing titanium and silicon) and tetrapropylammonium bromide (TPABr). The pre-addition of a certain amount of TPABr into the polymer-based precursor plays a very positive role in maintaining the high crystallinity and framework Ti incorporation rate of TS-1 zeolites under the premise that a relatively low concentration of tetrapropylammonium hydroxide (TPAOH) template is adopted in the following hydrothermal crystallization process. The condition-optimized TS-1 zeolite with a smaller particle size (300–500 nm) shows excellent catalytic activity, selectivity, and recyclability for the epoxidation of 1-hexene with H2O2as an oxidant, which can achieve a 75.4% conversion of 1-hexene and a 99% selectivity of epoxide at a reaction temperature of 60 °C, which is much better than the TS-1 zeolites reported in the previous literature. The relatively small particle size of the resultant TS-1 crystals may enhance the accessibility of the catalytically active framework Ti species to reagents, and the absence of non-framework Ti species, like anatase TiO2, and low polymerized six-coordinated Ti species could effectively inhibit the ineffective decomposition of H2O2and the occurrence of side reactions, leading to an improvement in the catalytic efficiency for the epoxidation of 1-hexente with H2O2.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhuwei Yang,Linsen Li,Xiao Yang,Hui Xiong,Riguang Zhang,Zhao Jiang
In this study, a series of Ni-CeO 2 /TS-1 (Titanium Silicalite-1) catalysts were synthesized for dry reforming of methane (DRM). Among them, 5Ni-10CeO 2 /TS-1 exhibited the highest catalytic performance with 89 % CH 4 and 93 % CO 2 conversions, 4.81 mol CH4 ·g Ni -1 ·h −1 and 4.99 mol CO2 ·g Ni -1 ·h −1 specific activities, 95.5 % H 2 /CO ratio after 50 h, accompanied by the good stability with 2.9 % CH 4 and 2.3 % CO 2 activity loss within 100 h. Combined with various characterizations, the structure–function relationship was also investigated. For the physical and morphological analysis, it was indicated that the appropriate CeO 2 content could effectively diminish, disperse the Ni nanoparticles, and maintain MFI backbone structure. For the electronic structure, the introduced CeO 2 could improve the amount and strength of the surface Ni-O-X (Ti or Ce) species by changing the interaction among Ni nanoparticles, TS-1 and CeO 2 . It led to more Ni nanoparticles in stronger electron-deficient state, as well as more medium-strength basic sites, favoring for the activation of CH 4 and CO 2 . However, Ni nanoparticles would be covered when excessive CeO 2 was introduced, preventing the exposure of the active sites. Therefore, only the suitable CeO 2 in the catalysts could significantly improve catalytic performance for DRM with long-term stability. Furthermore, the good anti-sintering and anti-coking properties of 5Ni-10CeO 2 /TS-1 were mainly dependent on the optimal amount of surface Ni-O-X species with high strength. In-situ DRIFTS (diffuse reflectance infrared spectroscopy) analysis demonstrated that the introduced CeO 2 could help catalyst favor for activating CH 4 and CO 2 molecules, and inhibiting the CH 4 overcracking and carbon accumulation, confirmed by the long-term measurement and structure analysis of spent catalysts.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2024
·
IF 4.7
Mengqi Wang,Bo Chen,Yan He,Zhili Li,Yuanyuan Ge
Titanium silicalite-1 zeolite (TS-1) has been widely used as a catalyst for the epoxidation of 1-hexene. However, fast synthesis of TS-1 with high activity and stability remains a great challenge. In this study, a new strategy using sodium persulfate (SPS) as a crystallization modifier was proposed for the accelerated synthesis of anatase-free TS-1. The anatase-free TS-1 (TS-20-SPS) could be obtained after 20 h of hydrothermal crystallization. TS-20-SPS had a low Si/Ti ratio (31) and achieved a high conversion (20 %) in the epoxidation of 1-hexene at room temperature (298 K), which was 200 % higher than that of TS-1 synthesized without adding SPS. The addition of SPS not only accelerated the crystallization due to the generation of ·OH, but also reduced the pH value of the system to avoid the generation of anatase. This SPS-assisted approach offers an avenue for the accelerated synthesis of high-performance, anatase-free TS-1.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Yue Wei,Gang Li,Cong Wang,Hongchen Guo
For solvent-free catalytic oxidations , low efficiency resulted from poor mass transfer and insufficient utilization of active centers remains a tough problem. Herein, we demonstrate a novel hybrid core-shell catalyst (TS@PMO) with an amphiphilic shell and a Ti-surface-enriched mesoporous TiO 2 -SiO 2 (TS) core to address this challenge. Such TS@PMO realizes its amphiphilicity via an ex situ formed periodic mesoporous organosilica (PMO) shell. Simultaneously, by a unique etching effect induced by organic precursor growth on [SiO 4 ] tetrahedra in TS core, active Ti sites are facilely enriched in near-surface layer of core and extra mesoporous cavities are introduced for substrate reservation. When applied for solvent-free epoxidation of methyl oleate (MO) with H 2 O 2 , TS@PMO exhibits remarkably boosted catalytic activity (X = 90.2%) and epoxide selectivity (S = 70.2%), overwhelming the unmodified titanosilicate (X = 63.7%, S = 49.2%) and Ti-containing organosilica (X = 39.8%, S = 25.0%). Such result benefits from an evidently enhanced interphase mass transfer and sufficiently accessible active Ti sites in TS@PMO. On the one hand, amphiphilic PMO shell can efficiently collect hydrophobic substrate and H 2 O 2 , while abundant mesopores in the shell offer open-path for them to access active sites in the core; on the other hand, an increased framework Ti (IV) density and their surface-enrichment in TS core greatly improve the utilization of active Ti sites. This study effectively makes up for the deficiencies of slow mass transfer and insufficient utilization of conventional titanosilicates in biphasic reactions, which paves a new avenue to exploit other hybrid catalysts for high-efficiency solvent-free catalysis.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yi-Tian Wang,Si-Ming Wu,Guo-Qiang Luo,Ge Tian,Bo-Jun Zeng,Li-Ying Wang,Shi-Tian Xiao,Jing-Xian Wu,Ao Wu,Kang-Jun Wu,Silvia Lenaerts,Xiao-Yu Yang
Dual active sites from acidic zeolite and Pd are not only capable of catalyzing multiple type of reactions, but could also generate unique functions owing to the synergy between metals and acidic sites. However, there are only a few reports on the investigation of the synergy of acid/Pd dual sites in TS-1. Herein, TS-1 confined Pd catalyst with mesoporous silica shell (Pd@TS-1 @meso-SiO 2 ) has been successfully synthesized and its synergy effect contributes to the enhanced conversion rate (19.2%) and selectivity (74.7%) on styrene oxidation . The interaction between Pd and TS-1 has been investigated by EPR and 1 H NMR techniques, the experimental measurements show an obvious change in the signal distribution of weakly acidic terminal hydroxyls and hydrogen-bonding silanols. The schematic illustration of selective styrene oxidation in the model of Pd@TS-1 @meso-SiO 2 is proposed to clarify the synergistic effect on styrene oxidation between TS-1 and Pd nanoparticles at an atomic-/nanoscale.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2016
·
IF 3.611
Qi Du,Yiping Guo,Huanan Duan,Hua Li,Yujie Chen,Hezhou Liu
Hierarchical TS-1 (HTS-1) zeolite has been successfully synthesized through a novel three-step crystallization method by using a cheap and eco-friendly polymer PVA as the mesopore template. The HTS-1 particles possess an interesting stacking structure and are constructed of smaller crystals with an average diameter of 30 nm. The mesopores of HTS-1 are formed by the stacking of the smaller TS-1 nanocrystals . The catalytic results show that the HTS-1 exhibits much higher catalytic activity than conventional TS-1 in the oxidative desulfurization of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) due to the presence of intracrystal mesopores. In addition, the three-step crystallization method plays a key role in the preparation of HTS-1, which effectively solves the problem that PVA is unstable and unsuitable to be used as mesopore template under high crystallization temperature .
研究领域:
材料化学
·
催化化学
·
纳米材料科学
·
环境化学
·
能源化工
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 10
·e202203687
·
IF 2.1
Min Zhang,Shenyong Ren,Qiaoxia Guo,Baojian Shen
Graphical Sheet-like zeolite TS-1 was synthesized under hydrothermal conditions by adding seed and urea. Liquid seed and pre-crystallization could adjust thickness of sheet-like sample in b-axis direction. Epoxidation of 1-hexene with H 2 O 2 catalyzed by sheet-like TS-1 gave high selectivity of 1,2-epoxyhexane. In zeolite TS-1, the straight channel parallelled to the b-axis direction has larger pore size and thus is main diffusion channel for molecules. Shorter b-axis brings about shorter diffusion channel, which can leads to higher adsorption and diffusion rate. Therefore, with regard to the morphology modification of MFI zeolites, many studies touch on short b-axis zeolites have been reported. Unfortunately, most of the preparation processes require harsh synthesis conditions and complex organic templates, and they are not conducive to large-scale applications. In this work, cheap organic additive urea and seed crystals were added to synthesize sheet-like TS-1, which boasts short b-axis. At the same time a pre-crystallization was performed at the aging solution stage. In the b-axis direction, the zeolite TS-1 prepared in this way had a minimum thickness of about 50 nm. This is because urea can inhibit the growth of crystals in the b-axis direction, and the guiding effect of the seed liquid also plays the function of adjusting the b-axis thickness. In the epoxidation of 1-hexene with H 2 O 2 when catalyzed by sheet-like TS-1, the selectivity of the target product 1,2-epoxyhexane was significantly improved.
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）