CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
Chenyang Zhao,Hongwei Zhu,Yujia Liu,Junjie Feng,Xiang Feng,Wei Xu,Zhe Yang,Bing Sun
The direct epoxidation of propylene has been a hot topic in the academic field for years. Researchers have spent extensive effort on the development of catalyst, however, only limited attention on the effect of reaction conditions, especially pressure. In this paper, we found for the first time that elevated pressure should favor the forward epoxidation reaction, it actually led to a drop of reaction rate in this system. We proposed explanation by considering the difficulty of gas molecules diffusing into and out of the micropores on the TS-1 zeolite surface. Higher pressure would inhibit the escaping of the gas molecules from the micropores and lead to carbon deposition inside the channel. To validate this hypothesis, we designed and compared catalysts with micropores blocked (BTS-1) and unblocked (TS-1) and found that the BTS-1 showed higher resistance to pressure change and significantly longer life time than the TS-1.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2018
·
IF 3.649
Qi Du,Yiping Guo,Pei Wu,Hezhou Liu
Hierarchically porous TS-1 (HTS-1) zeolite with nanocrystal aggregate structure has been successfully synthesized by hydrothermal and steam-assisted crystallization (SAC) method with the aid of polyvinyl alcohol (PVA). It has been found that the formation of mesoporous aggregates was attributed to the construction of PVA three-dimensional network. The mesoporous aggregate structure could be well maintained by SAC method, resulting in HTS-1 with either surface titanium enrichment or highly interconnected mesopores and high external surface. Both could contribute to the excellent catalytic performance of HTS-1 in oxidative desulfurization of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The TOF numbers of HTS-1 reached a very high value to 114.9 h −1 and 53.2 h −1 in the oxidation of DBT and 4,6-DMDBT, respectively. Moreover, the HTS-1 showed good stability and remained ∼90% of its initial activity even after 3 times cycle. The high catalytic activity and good stability suggest that HTS-1 is a promising catalyst for deep oxidative desulfurization.
研究领域:
催化化学
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材料科学
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环境化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
·
IF 4.539
Guojun Lv,Tao Wang,Yan Chen,Jiangzhang Wang,Xuyang Zou,Jun Lu,Fumin Wang,Xubin Zhang,Yi Zhai
Design of catalyst particles bearing excellent diffusion performance and suitable surface wettability is of great importance to the successful application of Pickering interfacial catalysis. In this study, selective oxidation reactions over hydrophobized hollow TS-1 zeolite were applied as probe reactions to investigate the influence of catalyst diffusion performance closely related to mesopore size on its catalytic activity. Hydrophobized hollow TS-1 zeolite particles were prepared via a post desilication treatment accompanied with precrystallization treatment. The synthesized hydrophobized hollow TS-1 zeolite was characterized by Scanning electron microscopy, Transmission electron microscopy , X-ray diffraction, UV–vis absorption spectrometry , Fourier-transform infrared spectroscopy and Nitrogen adsorption-desorption. Stable Pickering emulsions including 1-hexene-hydrogen peroxide, cyclohexene-hydrogen peroxide and cyclohexanone-water were prepared with hydrophobized hollow TS-1 zeolite particles as emulsifier . HTS-1–393(2)-S zeolite synthesized with precrystallization at 393 K for 2 h presented the maximum values of 43.9 mol/(Ti-mol·h) for 1-hexene epoxidation , 15.7 mol/(Ti-mol·h) for cyclohexene epoxidation and 247.3 mol/(Ti-mol·h) for cyclohexanone ammoximation. In addition, HTS-1–393(2)-S zeolite particles displayed good reusability for more than five cycles.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Guojun Lv,Yan Chen,Xuyang Zou,Jiangzhang Wang,Tao Wang,Xubin Zhang,Fumin Wang
There are few reports concentrated on the interactions between lipophilic surfactants and hydrophobized hollow TS-1 zeolite particles in the stabilization of emulsions. In this study, hydrophobized hollow TS-1 zeolite particles were synthesized and applied as emulsifier to stabilize the W/O Pickering emulsions employing cyclohexanone and water, and the influence of addition of lipophilic Span 80 on the stability of the W/O Pickering emulsions was systematically studied. Surprisingly, a phase inversion was induced by simply changing the Span 80 concentration. At fixed concentration of TS-1 zeolite particles (2 wt%), emulsions are water in oil (W/O) when the concentration of Span 80 is lower than 0.5 mM. Then the emulsions invert to oil in water (O/W) when the Span 80 concentration is between 1 mM and 8 mM. In this process, different emulsifiers dominate the composition of the interfacial layer, and the emulsion type is correspondingly controlled. When Span 80 concentration is lower than 0.5 mM, hydrophobized hollow TS-1 zeolite particles are in domination, and W/O emulsions are obtained. At Span 80 concentration of 1–8 mM, the emulsions are stabilized mainly by Span 80, and the emulsion type is O/W.
研究领域:
化学工程
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材料科学
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界面化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2024
·Vol. 31
·期 3
·793-808
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IF 2.5
Yang Zhaosheng,Tang Guoqiang,Li Yichuan,Niu Xiaoyue,Cheng Lingyao,Chai Yongming
TS-1 molecular sieve spherical membranes loaded on small-sized carriers with hierarchical pore structures and high framework-titanium contents could both exhibit high catalytic performances and facilitate the separation from the products after the reaction. In this paper, a simple in situ static crystallization method was used to achieve the construction of hierarchical porous TS-1 molecular sieve membranes on the surfaces of 400-µm spherical ZrO 2 carriers using cetyltrimethylammonium bromide (CTAB) and soluble starch as mesoporous templating agents. Through the catalyst characterization and performance evaluation, soluble starch was finally selected as the mesoporous templating agent, and the film-forming mechanism was investigated by examining the effects of the proportion of precursor liquid and the crystallization conditions. In the chloropropene epoxidation reaction, the effective utilization of H 2 O 2 and the selectivity of epichlorohydrin (ECH) reached 96.72% and 93.85%, respectively.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Xiaojing Song,Xiaotong Yang,Tianjun Zhang,Hao Zhang,Qiang Zhang,Dianwen Hu,Xinyu Chang,Yingying Li,Ziyi Chen,Mingjun Jia,Peng Zhang,Jihong Yu
Developing an effective strategy to synthesize perfect titanosilicate TS-1 zeolite crystals with desirable morphologies, enriched isolated framework Ti species, and thus enhanced catalytic oxidation properties is a pervasive challenge in zeolite crystal engineering. We here used an amino acid l-carnitine as a crystal growth modifier and ethanol as a cosolvent to regulate the morphologies and the Ti coordination states of TS-1 zeolites. During the hydrothermal crystallization process, the introduced l-carnitine can not only tailor the anisotropic growth rates of zeolite crystals but also induce the formation of uniformly distributed framework Ti species through building a suitable chemical interaction with the Ti precursor species. Condition optimizations could afford the generation of perfect hexagonal plate TS-1 crystals and elongated platelet TS-1 crystals enriched in tetrahedral framework Ti sites (TiO4) or mononuclear octahedrally coordinated Ti species (TiO6). Both samples showed significant improvement in catalytic activity for the H2O2-mediated epoxidation of alkenes. In particular, the elongated platelet TS-1 enriched in “TiO6” species afforded the highest activity in 1-hexene epoxidation, with a turnover frequency (TOF) of up to 131 h–1, which is approximately twice as high as that of the conventional TS-1 zeolite (TOF: 65 h–1) and even higher than those of the literature-reported TiO6-containting TS-1 catalysts derived from the hydrothermal post-treatment of TS-1 zeolites. This work demonstrates that the morphologies and the titanium coordination states of TS-1 zeolites can be effectively tuned by directly introducing suitable crystal growth modifiers, thus providing new opportunities for developing highly efficient titanosilicate zeolite catalysts for important catalytic applications.
研究领域:
材料科学
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催化化学
·
晶体工程
✓ 已验证
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
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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
FUEL
·
2025
·
IF 7.5
Kaiwei Wang,Hao Ruan,Fumin Wang,Yi Zhai,Mingshuai Sun,Yan Chen,Jiaxing Zhang,Yihao Wang,Xuyang Zou,Xubin Zhang
The construction of abundant TiO 6 active sites within the zeolite framework is essential for further enhancing the catalytic performance of TS-1 zeolite. Here, we employ a strategy involving treatment with a mixture of amines and ammonium salts to generate abundant TiO 6 species within zeolites synthesized with the assistance of N,N-dimethylformamide (DMF). It was observed that during the post-treatment process, the presence of amines and ammonium salts plays a key role for the formation of highly active TiO 6 species. The incorporation of DMF can significantly enhance the TiO 6 content in the post-treated zeolite, increasing it to 61.5 % compared with 28.5 % in the zeolite synthesized without DMF. The effect of the DMF/SiO 2 ratio in the synthesized gel on the morphology and catalytic performance was also examined. It is noteworthy that the incorporation of DMF influences the microenvironment of the Ti active sites following post-treatment. 1 H MAS NMR analysis reveals that the characteristic peaks corresponding to Ti-OH and isolated Si-OH groups in the DMF-synthesized catalyst are significantly intensified after treatment with amines and ammonium salts. When H 2 O 2 is employed as an oxidant, the optimal catalytic performance achieves a cyclohexene conversion of 51.1 % and a cyclohexene oxide yield of 39.4 %, with a high TOF value of 92.77 h −1 . Notably, the catalyst exhibits a significantly conversion rate of 79.4 % and a yield of 72.7 % using O 2 as the oxidant.
研究领域:
催化化学
·
材料科学
·
无机化学
·
石油化工
·
绿色氧化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Huanxu Teng,Meihua Zhu,Yixuan Shao,Siqi Shao,Qingsheng Wu,Ziming Li,Xiangshu Chen,Hidetoshi Kita
Supported TS-1 zeolites were successfully synthesized on α-Al 2 O 3 microsphere by secondary hydrothermal synthesis, which were placed in the fixed-bed reactor and catalyzed the oxidation of isopropanol(IPA) with hydrogen peroxide. Effects of synthesis parameters on the morphology and catalytic activity of the supported TS-1 zeolites were systematically studied in this work. Size of α-Al 2 O 3 microsphere, and crystallization temperature could determine the coverage, titanium coordination, and titanium content of the supported TS-1 zeolites. When the crystallization temperature and H 2 O/SiO 2 molar ratio of the initial synthesis solution were 150 °C and 120, the titanium-rich and anatase-free supported TS-1 zeolites were prepared on the ca. 1 mm α-Al 2 O 3 microsphere support. The supported TS-1 zeolites showed an excellent catalytic performance and stability for isopropanol oxidation, the isopropanol conversion and acetone selectivity reached 100 % within 2 h. Kinetic studies showed that the reaction conformed to the Langmuir-Hinshelwood mechanism and that the apparent activation energy was only 4.57 kJ/mol.
研究领域:
催化化学
·
材料化学
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化学工程
·
多相催化
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 10
·6205-6213
·
IF 12.732
Jiacheng Xing,Danhua Yuan,Hanbang Liu,Yansi Tong,Yunpeng Xu,Zhongmin Liu
The synthesis of TS-1 zeolites is regarded as a milestone in zeolite history, and it has led to the revolution of the green oxidation system of using H2O2 as an oxidant, leaving only water as the byproduct. However, because of the highly hydrolyzable titanium source, the preparation of TS-1 requires complex synthesis conditions. Moreover, the difference in the hydrolysis rate between the silicon source and titanium source tends to increase the difficulty of titanium insertion into the framework, and it is easy to generate extra-framework Ti species during the synthesis. Here, a high-quality TS-1 zeolite with a large external surface area and free of extra-framework Ti species has been successfully synthesized by using a kind of novel polymer containing titanium and silicon. Due to the high hydrolysis resistance of the polymer reagent, a good matching of the hydrolysis rate between the silicon source and the titanium source is realized during crystallization, which facilitates the incorporation of titanium into the framework. Furthermore, the TS-1 zeolite exhibited excellent catalytic performance in n-hexane oxidation with hydrogen peroxide as the oxidant. This method of synthesizing zeolites from polymers is expected to be widely applied for the synthesis of other titanium-containing zeotype materials.
研究领域:
化学
·
材料科学
·
催化
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）