NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 35
·16752-16763
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IF 3.925
Kai Guo,Aizeng Ma,Zijian Wang,Jinzhi Li,Bingfeng Wu,Tong Liu,Dadong Li
The design of various hierarchical structures and morphologies of ZSM-22 zeolite catalysts is attempted through a post-treatment using different concentrations of NaOH and subsequently treating with HCl solution including fluosilicic acid (H2SiF6) and then loading Pt on their surfaces. The effects of samples on textural characters, acidity, as well as n-heptane catalytic hydroisomerization evaluation were examined. The formation process of the hierarchical structures was further investigated. Test and evaluation results indicated that samples treated with 0–0.5 M NaOH and subsequently treated with 6.0 M HCl and 0.1 M H2SiF6 were much more controllable and reasonable due to the better structure-activity relationship of the catalyst by changing crystal morphologies and introducing hierarchical structures. Indeed, PZH-0.3 exhibited 81.1% of the highest n-heptane conversion and 76.4% of total i-heptane yield in the n-heptane catalytic hydroisomerization process at 260 °C, PZH-0.5 displayed 13.6% of the maximum multi-branched i-heptane yield, which was above 104.1% in comparison with PZ-0 at 320 °C. Moreover, PZH-0.3 presented the highest n-butane yield, which possessed a proportion of 65.9% in the butane component of cracking products at 340 °C and improved an average of 16% and 22 times when utilizing PZ-0 and Pt/ZSM-5 catalysts. Additionally, the mechanism of the reaction process is briefly depicted according to the distribution of the reaction products. The regulation of zeolite both on crystal morphologies and pore hierarchy has obvious advantages in the hydroisomerization process, which can improve the composition of multi-branched isomers with high octane number effectively as well as supply raw materials for the chemical industry.
研究领域:
催化化学
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石油化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Yan Zheng,Liying Fang,Yan Yan,Shujie Lin,Zhaohui Liu,Yanzhao Yang
The silicone ionic liquid, 1-methyl-3-[tri-(trimethylsiloxy)]silylpropyl-imidazolium chloride ([Si 4 mim]Cl), was first used for the construction of the W/O microemulsion system and the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was applied for palladium extraction for the first time. The stability of [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was characterized by the Turbiscan Lab. For the Pd (II) extraction by the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system, primary parameters (namely, the vibration time, the [Si 4 mim]Cl concentration, the phase ratio and the additives) affecting the palladium extraction was investigated to optimize the process. Under the optimum conditions, the extraction percentage of Pd (II) is up to 98%. Afterwards, the ionic-exchange mechanism of Pd (II) extraction by the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was confirmed by the Job Method and analyzed by FT-IR spectra. The stripping of Pd (II) from the microemulsion phase was also studied using the NaCl solutions, indicating a high stripping efficiency. At last, the selectivity of the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system to Pd (II) from other metals (Cu (II), Co (II), Ni (II), Fe (III), Al (III) Zn (II), Ce (III), Li (I), Mg (II) and Sn (IV)) was demonstrated to be quite high. The results of our work indicate that the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system is a promising approach for Pd (II) extraction.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2025
·Vol. 155
·期 3
·1-11
·
IF 2.4
Wen Chenglong,Liu Kang,Lu Yi,Wu Xintian,Li Shuning,Lu Mohong,Zhu Jie,Li Mingshi,Song Chunshan,Lu Xiaosong
Ni/SAPO-11 catalysts with highly dispersed Ni (TA-Ni/SA-11) were prepared using tartaric acid as a dispersant. The effect of the tartaric acid content on the physiochemical properties of the TA-Ni/SA-11 catalysts and their n-heptane hydroisomerization performance were investigated. TA-Ni/SA-11 exhibits smaller Ni particles and more Ni active sites in comparison to conventional Ni/SAPO-11 prepared via the impregnation method due to the interaction between tartaric acid and Ni 2+ . As the molar ratio of tartaric acid and Ni 2+ (n TA /n Ni ) increases, the number of Ni active sites in TA-Ni/SA-11 rises, while the surface area and relative crystallinity decrease because of the dealumination of SAPO-11. When n TA /n Ni is 0.75, 0.75TA-Ni/SA-11 presents the highest n-heptane conversion of 82.4% and isomer selectivity of 90.5%, as well as the lowest cracking selectivity of 9.0% at 380 °C, 1.5 MPa, 2 h − 1 , and a volume ratio of H 2 to n-heptane of 400 among these catalysts. Graphical
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Zhirong Yang,Yao Shi,Yan Lin,Li Luo,Nan Song,Jianyang Lin,Chong Peng,Baokuan Sui,Jing Zhang,Gang Qian,Xinggui Zhou,Xuezhi Duan
Regulation of pore hierarchy has been an important subject in the design of industrial catalysts. Synthesis of alumina without template/additive often results in poor control of morphologies, porosities, and metal dispersion thereafter. Herein, alumina microrods with a tailored pore hierarchy (Rod2) were fabricated without template/additive by tuning the pore structure of the synthetic precursors, which were used as supports of Pt for n -heptane reforming. Improved toluene selectivity was observed at low space velocities as a result of promoted dehydroisomerization of pentacyclic hydrocarbons, presumably due to a combined effect of the desired pore hierarchy and rod morphology. The Pt/Rod2 also showed better resistance to carbon deposition while maintaining good metal dispersion, as compared to alumina supports with spherical morphology or uncontrolled pore hierarchy. The simulation results revealed that the improved toluene selectivity of Pt/Rod2 is attributed to the proper pore combination of meso -pore1 (6–40 nm) and meso -pore 2 (40–300 nm).
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
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Bingjie Chen,Peng Liu,Qiang Xu,Zhandong Wang,William L. Roberts,Heinz Pitsch
As an important component of transportation fuels, toluene has little reactivity in the low temperature regime. However, the low temperature reactivity of toluene may be enhanced by the reaction of other reactive components (e.g., n-heptane) in fuel mixtures. This work examines low temperature oxidation of toluene in jet stirred reactor oxidation of an n-heptane/toluene mixture (1:1 in mole, 500–800 K, ϕ=0.5, τ=2.0 s, p = 1 bar). Two measurement techniques, time of flight molecular beam mass spectrometry using synchrotron vacuum ultraviolet radiation as the photon ionization source and gas chromatography mass spectrometry, were applied to identify and measure 32 species, including four polycyclic aromatic hydrocarbons (PAH) and oxygenated PAH (OPAH). Numerical simulations using the latest kinetic model from Lawrence Livermore National Laboratory predicted the mole fractions of fuel molecules and small intermediates well, but under-predicted the mole fractions of oxygenated aromatics (phenol, benzyl alcohol, and cresol). The identification of benzyl peroxide–an important intermediate–supported the proposed formation pathways for the identified aromatics. Model analysis highlighted the influence of H-atom abstraction, OH/H radical ipso substitution, and OH addition reactions of toluene on the formation of phenol , benzyl alcohol, and cresol, which may further grow to OPAH molecules by the addition of benzyl radical from H-atom abstraction of toluene.
研究领域:
燃料化學
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反應動力學
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2018
·
IF 3.649
Li Gao,Zhiyuan Shi,Ubong Jerome Etim,Pingping Wu,Dezhi Han,Wei Xing,Svetlana Mintova,Peng Bai,Zifeng Yan
Beta-MCM-41(BM) composites consisting of Beta zeolite grown on MCM-41 type mesoporous structure were prepared. The composite materials were used as a support for stabilization of Pt. The Pt containing catalysts (Pt/HBM) were applied in n-heptane hydroisomerization reaction. The Pt/HBM catalysts showed higher n-heptane conversion and higher selectivity to isoheptanes in comparison to pure Beta and MCM-41. The results were explained by the accelerated diffusion of isoheptanes in the Pt/HBM composites, and the high concentration of acid sites with a moderate strength in the composites, which reduced the cracking of reactants and products. Based on the experimental results, an indexed isomerization factor (IIF) was deduced, which is correlated with the physical properties of the supports. The results indicated that the isoheptane yield of the catalysts is strongly dependent on the support (IIF). The general IIF descriptor for predicting the isomerization performance of support materials can provide precise guidance for the design of new micro-mesoporous composites.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Zhen Liu,Hu Li,Yi Wang,Yu Wang,Peng Peng,Xinmei Liu
Due to higher thermal and hydrothermal stability, suitable acidity properties, Beta zeolite is considered as promising catalyst for naphtha catalytic cracking process. However, high cost and environmental pollution issue limit its industrial application by using high content of N-containing organic structural directing agent (SDA). In this paper, different SiO 2 /Al 2 O 3 ratios of Beta zeolites were prepared assisting by seeds induced method with low SDA and cheap industrial silica sol as the silicon source. Physical and chemical properties of as-prepared Beta zeolites were characterized by XRD, N 2 adsorption-desorption, NH 3 -TPD, Py-FTIR and SEM. N-Heptane was used as model compound for catalytic cracking performance evaluation. The results showed that Beta zeolite with high SAR was successfully synthesized, which had well defined crystallinity, proper specific surface area and pore structure, high B/L ratio and strong acid site. n-Heptane catalytic cracking performance showed high yield of low-carbon olefins with relative low activity on hydrogen transfer reaction and coke formation.
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
CATALYSIS TODAY
·
2022
·
IF 6.562
Yifan Zheng,Hongxin Ding,Enhui Xing,Jinghua Zhou,Yibin Luo,Jichang Liu,Kake Zhu
ZSM-48 is a unidimensional zeolite that is frequently used as acid component of bi-functional hydroisomerization catalyst. As selectivity towards unwanted cracking products increases with retention time of isomerized products inside micropores, shortening their retention time inside the micropores by reducing channel length offers an effective way to improve isomerization selectivity. Direct synthesis of unidimensional zeolitic crystals with reduced channel axis is particularly difficult, since they habitually grow into rod-like shape along their channel direction. Post-synthetic bead-milling is a cost effective, mechanochemical method to decrease crystal size of zeolites from micro meter to nano meter scale, but suffers from amorphization or partial destruction of zeolitic crystals. Consequently, a post-milling recrystallization process is often entailed to remedy the destructed domains, which, nonetheless, readily causes secondary crystal growth and formation of bulky crystals that compromises the effect of bead-milling. Here, we show that porogen-assisted recrystallization can overcome the problem to fabricate channel axis reduced ZSM-48 nanocrystals. The Si/Al ratio is tunable between 30 and 200 and the acidity is largely preserved after recrystallization. The catalytic advantages of the obtained material are demonstrated in catalytic n -heptane hydroisomerization. The obtained ZSM-48 nanocrystal with Si/Al ratio of 100 outperforms the rest samples and shows enhanced isomerization yield (72% vs 62%) with respect to the parent sample. By combined diagnoses of the impact of diffusion length on product selectivity (product shape selectivity) and kinetic studies , selectivities to monomethyl branched isomers (2-methyl hexane and 3-methyl hexane) and small bulky dimethyl branched isomers (2,3- and 2,4-dimethyl pentane) are attributed to product shape selectivity, whereas the formation to bulky dimethyl branched isomers (2,2- and 3,3-dimethyl pentane) is hindered mainly by transition-state shape selectivity. The combined destructive-constructive synthetic protocol and the revelation of the origin of shape-selectivity in n -heptane hydroisomerization are useful for hydroisomerization catalyst design.
研究领域:
催化材料
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化学工程
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2024
·Vol. 11
·期 3
·036505
·
IF 1.8
Zhen Jiang,Liduo Chen,Yanhong Cui,Yanhua Suo,Wei Zhang,Yisi Zhou,Yingjun Wang
The monometallic Pt/SAPO-11 and bimetallic Ni-Pt/SAPO-11 catalysts were synthesized with Instant Exactness Synthesis (IES) method and characterized by XRD, nitrogen adsorption–desorption, SEM, TEM, FT-IR, Py-IR, NH3-TPD and XPS, and their properties were evaluated for the n-heptane hydroisomerization. The catalysts had spherical structure and moderate acid strength, and exhibited good n-heptane conversion and catalytic selectivity toward n-heptane isomers. Typically, Ni-Pt/SAPO-11 exhibited an isomer selectivity of 80.9% with a conversion of 69.9% at 310 °C, which was obviously better than Pt/SAPO-11 (isomer selectivity of 75.1% with a conversion of 60.6% at 310 °C). Moreover, the Ni-Pt/SAPO-11 catalyst displayed higher percentage of i-heptane (79%) and lower percentage of n-heptane (6%) than Pt/SAPO-11. The continuous test of 360 min indicated Ni-Pt/SAPO-11 catalyst had good catalytic stability. Bimetallic Ni-Pt alloy loaded on SAPO-11 had significantly effect on catalytic properties of n-heptane hydroisomerization.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2024
·
IF 2.3
Zhu Mengxuan,Xu Wenqi,Wang Longyang,Wang Rui,Jiang Heng,Jin Changzi
Developing sustainable synthesis method of versatile zeolites to overcome the shortcoming of traditional process is of significant for development of green chemistry and environmentally friendly techniques. In this work, MFI zeolite (ZSM-5) was synthesized through organotemplate-, solvent- and seed-free sustainable process comprising physical grinding and quasi-solid state crystallization and utilizing commercial silica gel or Stöber colloidal SiO 2 as silica source. The key influencing factors to this sustainable synthesis process, such as starting material composition, crystallization temperature and time, had been unambiguously investigated by combining a series of characterization techniques. It is revealed that the starting material with SiO 2 /Al 2 O 3 and Na 2 O/SiO 2 at 30–40 and 0.072, respectively, is suitable to obtain zeolite product with high crystallinity. The presence of right amount of water (or alcohol) is also crucial. In addition, this green synthesis method can be extended into the fabrication of encapsulated metal-zeolite bifunctional catalyst, which is effective in hydroisomerization of n -heptane. These results are instructive for development of sustainable synthesis of aluminosilicate zeolites and derived heterogeneous catalysts. Graphical Abstract
研究领域:
催化化学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2025
·
IF 3.2
Zhu Mengxuan,Liu Yifan,Ma Jiaxin,Wang Longyang,Wang Rui,Jiang Heng,Jin Changzi
Developing the novel green routes for synthesis of important aluminosilicate zeolites is of significant for theoretical research and practical application. In this work, MCM-22 zeolite with MWW-topology was synthesized through seed-assisted interzeolite transformation from FAU zeolite without using additional organic template. The key influence factor to the synthesis process was investigated and the zeolite products were characterized by a series of modern techniques. It has been shown that not only the presence of MCM-22 seed, but also the appropriate SiO 2 /Al 2 O 3 and Na 2 O/SiO 2 molar ratio of starting synthesis gel with were crucial to synthesize pure MWW zeolite. The hexamethyleneimine template occluded in seed also played a key role in successful interzeolite transformation, but did not participate structure-directing of MWW product. Although the zeolite synthesized by interzeolite transformation showed lower surface area and pore volume compared with MCM-22 zeolite prepared by conventional route, the Pt modified sample exhibited promising catalytic performance in hydroisomerization of n -heptane. Graphical
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Li Gao,Ubong Jerome Etim,Zhiyuan Shi,Wei Xing,Pingping Wu,Dezhi Han,Peng Bai,Zifeng Yan
A Beta-KIT-6 (BK) micro-mesoporous composite material was assembled using zeolite Beta seed solution as raw material. BK composite contained both zeolite Beta units and three-dimensional cubic Ia3d mesostructure of KIT-6, which served as a catalyst support for hydroisomerization of n-heptane. The composite was characterized by a variety of techniques. Results show that catalyst Pt/HBK using the composite as the support exhibited the highest isoheptanes yield among all catalysts, which is attributed to both appropriate surface acidity and excellent mass transfer properties of Beta-KIT-6 composite. Experimental results verified that the indexed isomerization factor as a general performance descriptor could accurately predict the hydroisomerization performance of support materials.
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
危险品化学品经营许可证（带存储）