FUEL
·
2022
·
IF 8.035
Linjie Guan,Chengming Huang,Dingmei Han,Binbin He,Linhua Zhu,Dedong He,Yi Mei,Yun Zu
A series of HZSM-5 zeolites are fabricated to make it cross-link with an external ultrathin siliceous layer by chemical liquid deposition and the corresponding thickness is measured by TEM and XPS analysis. In situ FTIR experiments disclose that the external surface acidic sites of HZSM-5 zeolite can be covered even by siliceous monolayer (0.7 ∼ 1.3 nm, HZ5-S1). In comparison to parent HZSM-5, the catalytic cracking performance of n-butane over the modified zeolites are evidently enhanced. In particular, the n-butane conversion rate per Brønsted acid site over the HZ5-S2 (16.02 min −1 ) at 550 °C is 2.82 times than that over the HZSM-5 (5.68 min −1 ). Meanwhile, the diffusion properties of n-butane over the zeolites are quantified by in situ FTIR spectroscopic analysis. Negative correlation between steady-state diffusivity and n-butane conversion rate per Brønsted acid site can be found, which unravels the origin of the progressive decrease in the catalytic stability. Under comparable conditions, more advantages can be greatly achieved by HZ5-S1 catalyst in the catalytic activity and the yields to light olefins due to the benign diffusivity and the elimination of external surface acidic sites. This study can provide a guidance for the understanding of diffusion intensification and the rational design of superior catalyst for the catalytic cracking reactions of alkanes.
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
FUEL
·
2023
·
IF 7.4
Linjie Guan,Meiyu Liu,Honghai Liu,Li Zhang,Yiming Zhang,Yucai Qin,Binbin He,Yi Mei,Yun Zu
The regulation of the engineering regionally spatial framework aluminum (Al F ) distribution in MFI channels has been considered as an effective way for the production of light olefins by targeted fluid catalytic cracking (TCO) technology. In this work, ZSM-5 zeolites with controlled Al F distributions are facilely synthesized by tuning the combinations of pentaerythritol (PET), tetrapropylammonium (TPA) and Na cations. The Al F atoms in the prepared HZ5-[PET + Na] and HZ5-[TPA] samples are enriched in the straight channels and intersection channels, respectively, which are favorable to the n-butane monomolecular reaction pathway, promoting the propylene production. Whereas the Al F atoms in the HZ5-[TPA + Na] sample are simultaneously distributed in both the straight and intersection channels, the n-butane molecules preferentially take place monomolecular reaction in the straight channels to generate carbonium ions (e.g., C 2 H 5 + , C 3 H 7 + and C 4 H 9 + ). Subsequently, all of them enter into the intersection channels to induce the occurrence of bimolecular reaction. Such a process is conducive to the formation of ethylene. These insights can help to clarify the catalytic behavior of regional framework acid sites in ZSM-5 channels and then provide an effective approach to design efficient TCO 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
Molecular Catalysis
·
2026
·
IF 4.3
Tong Yu,Junyu Zhao,Jie Zhang,Qian Li,Tangze Deng,Jinwei Chen,Gang Wang,Ruilin Wang
Vanadium phosphorus oxide (VPO) is regarded as the most efficient catalyst for the selective oxidation of n- butane towards maleic anhydride (MA). However, to a certain extent, its industrial applications are restricted by the “trade-off” effect between n -butane conversion and MA selectivity. Here, an iron phosphorus oxide (FePO) catalyst was synthesized using a modified molten salt method and characterized. The optimum Fe 0.25 PO catalyst achieved considerable catalytic performance with n -butane conversion of 59.77 %, MA selectivity of 59.07 %, and MA yield of 35.31 %. Various characterizations revealed the relationship between the catalytic performance and physicochemical properties such as the crystal structure, surface P/Fe ratio, oxygen species, and surface acidity. The results indicated that the ordered Fe(PO 3 ) 3 structure was the primary active phase for the Fe 0.25 PO catalysts, in which the abundant exposure of Fe 3+ sites and active oxygen species contributed to improving the reactivity and n -butane conversion. In addition, acid sites distribution, Lat-O/Sur-O, Fe 3+ /Fe 2+ , P/Fe, and O/Fe are critical factors for determining the activity and MA selectivity. The exploration of FePO catalysts offers a guideline for the development of high-performance catalysts to replace VPO for n -butane selective oxidation to MA.
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2026
·
IF 4.4
Xing Zhong-Lei,Jiang Run-Yuan,Yang Ting-Yu,Zhang Li-Ping,Lan Hao-Ling,Wang Shao-Min,Yang Qing-Yuan
The close similarity in molecular dimensions and physicochemical
properties between n -butane ( n -C 4 H 10 ) and isobutane (iso-C 4 H 10 ) makes their separation a persistent industrial challenge. In this
work, we employ two copper-based coordination networks, Cu-APC and Cu-MPC , constructed from amino- and methyl-functionalized
pyrimidine-5-carboxylate ligands, respectively, for n -C 4 H 10 /iso-C 4 H 10 separation.
The two frameworks exhibit distinct interlayer channel apertures (5.2
Å for Cu-APC and 4.1 Å for Cu-MPC ), enabling a systematic comparison of pore-chemistry effects on
C4 isomer discrimination. Cu-APC exhibits a remarkable n -C 4 H 10 uptake of 33.6 cm 3 ·g −1 under the conditions of 298 K and 100
kPa, together with an adsorption ratio of 4.36 for an equimolar n -C 4 H 10 /iso-C 4 H 10 mixture. DFT calculations were performed to investigate the host−guest
interactions. The results indicate that n -C 4 H 10 is preferentially stabilized within the 2D framework
via synergistic C−H···π and C−H···N
contacts, with measured distances of 3.42 Å and 3.15−3.68
Å, respectively. Cyclic fixed-bed breakthrough experiments further
confirm the excellent stability and regenerability of Cu-APC , positioning it as a viable candidate for the energy-saving separation
of n -C 4 H 10 from C4 alkane isomers.
✓ 已验证
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DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Linjie Guan,Chengming Huang,Dingmei Han,Linhua Zhu,Yi Mei,Dedong He,Yun Zu
Three zeolites ZSM-5, ZSM-35 and ZSM-22 are applied in n -butane cracking to reveal the influence of regional differences in Brønsted acid sites on reaction pathways. The Brønsted acid sites located in the channels of ZSM-5 exhibit a higher catalytic activity and yields to light olefins (especially the ethylene), which can be attributed to more relative contribution of bimolecular pathway. In comparison, more Brønsted acid sites are situated on the external surface or micropore mouths of ZSM-35 and ZSM-22, which are beneficial to propylene production. Note-worthily, almost no propane production on the two zeolites implies the predomination of monomolecular pathway. In situ FTIR technique further discloses that the difference in the reaction pathways is tailored by adsorption configurations of n -butane at two types of Brønsted acid sites. Under comparable conditions, the ZSM-5 performs a relatively good catalytic stability through bimolecular pathway. Furthermore, the correlation between deactivation rate and light olefins reveals that the enhancement of propylene selectivity accelerates the deactivation of ZSM-35 and ZSM-22. While, promotion on the ethylene selectivity is a significant inducement for the deactivation of ZSM-5.
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
Processes
·
2021
·Vol. 9
·期 9
·1487
·
IF 2.847
Muhammad Faizan,Kifayat Ullah Khan Niazi,Hasnain Nawaz,Niaz Muhammad,Hao Li,Fei Dai,Ruirui Zhang,Ruixia Liu,Suojiang Zhang
In recent work, deep eutectic solvents (DESs) as ionic liquid analogues have been abundantly used in catalysis. Herein, vanadium phosphorus oxide (VPO) catalysts were synthesized from mono-, bi-, and tri- metallic DES of Nb, Zr, and Mo metal dopants as structure-directing agents and electronic promoters for n-butane selective oxidation towards maleic anhydride. Higher MA selectivity and larger n-butane conversion was successfully obtained using the newly developed catalysts, while oxidation by-product COx(CO, CO2) was minimized. Characterization techniques including FTIR, DSC, XRD, TEM, SEM, EDS, Raman spectroscopy, TGA, XPS, and NH3-TPD were employed to fully characterize the DESs, precursors and catalysts. This work led to an increase of 7.8% in MA mass yield with 16% more n-butane conversion as compared to an unpromoted VPO catalyst. Moreover, the utilization of a low-carbon alkane brought in a green impact on the chemical plant as well as the environment.Keywords:deep eutectic solvent;vanadium phosphorus oxide;n-butane selective oxidation;structure directing agent;electronic promoter
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Xia Zhang,Haibo Wang,Lianke Gou,Lanpeng Li,Aijun Duan,Zhengkai Cao
Serial VPO catalysts with different crystal structures were prepared by adjusting the ratios of air and N 2 in the calcination process. The precursors and vanadium phosphorus oxide (VPO) catalysts were characterized by various measurements. As the air and N 2 ratios were lower than 1:1, the ordered VOHPO 4 ·0.5H 2 O phase was mainly formed in the precursors during calcination. However, as the ratio of air to N 2 reached 3:1, amorphous VOPO 4 phases were formed over the surface of the precursor during calcination, which prevented the formation of ordered V5+ species over the surface of the VPO catalyst after activation. Meanwhile, a high proportion of VOHPO 4 ·0.5H 2 O in the precursor could facilitate more formation of the ordered α 1 -VOPO 4 phase over the surface of the VPO catalyst. Interestingly, the crystal structure over the surface of active VPO catalysts was totally different from the core of VPO catalysts. There were more P species and V species with 5+ existing over the surface of the VPO catalysts. The evaluation results of n-butane oxidation showed that when the ratio of air to N 2 was 1:3, the corresponding VPO-1A catalyst presented the highest conversion of n-butane and yield of the MA product (57.6 m% at 412 °C). The reason should be related to the fact that the VPO-1A catalyst possessed the highest acidity and proportions of surface V5+ species and Sur-O species. As the ratio of air to N 2 reached 3:1, the VPO-3A catalyst showed the poorest performance in the oxidation of n-butane, which could be due to the formation of inactive and amorphous VOPO 4 phases over the surface of the VPO catalyst. Finally, kinetic and thermodynamic models were established and calculated to investigate the characteristics of n-butane oxidation reactions for various VPO catalysts.
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 THERMAL ANALYSIS AND CALORIMETRY
·
2014
·Vol. 117
·期 2
·603-610
·
IF 2.206
Liu Jialin,Li Jingrui,Fan Mengjin,Zhang Junying,Cheng Jue
Aromatic amine curing agent with flexible unit in backbone, 1,4-bis (4-diaminobenzene-1-oxygen) n -butane (DDBE), was synthesized, and the structure was confirmed by FT-IR and 1 H NMR. The curing kinetics of tetraglycidyl methylene dianiline (TGDDM, or AG80) using DDBE and 4,4′-bis-(diaminodiphenyl) methane (DDM) as curing agents, respectively, were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TG, respectively. The results showed that the activation energy of AG80/DDBE system was slightly higher than that of AG80/DDM system. Šesták-Berggren model can generally simulate well the reaction rates of these two systems. DMTA measurements showed that the storage modulus of cured AG80/DDBE is similar to that of cured AG80/DDM at the temperature below glass transition temperature ( T
g ) and lower than that of cured AG80/DDM at the temperature above glass transition temperature, while T
g of cured AG80/DDBE is lower than that of cured AG80/DDM. TG showed that the thermal stabilities of these two cured systems are similar.
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
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2022
·
IF 6.76
Muhammad Faizan,Hao Li,Yumei Liu,Kexin Li,Shuang Wei,Ruirui Zhang,Ruixia Liu
Currently, deep eutectic solvents (DESs), as an exclusive class of ionic liquid analogs, are extensively employed in various fields. Herein, vanadium phosphorus oxide (VPO) catalysts assisted by copper-based deep eutectic solvent (Cu-DES) as an electronic promoter and structure directing agent were ingeniously synthesized and exploited in the selective oxidation of n-butane to maleic anhydride (MA). The DES is efficient, cost effective and highly green compared to conventionally use metal inorganic modifiers. Cu-DES was prepared from a eutectic mixture of an organic salt (ChCl) and a metal salt hydrate/metal salt of cupric (Cu(NO 3 ) 2 .3H 2 O, CuCl 2 ) and cuprous (CuCl) salt with a molar ratio of 1:1–1:3, which notably improved the catalytic performance compared to that of an unpromoted VPO catalyst. The MA selectivity and n-butane conversion of Cu–DES–VPO increased significantly, while the CO x (CO and CO 2 ) selectivity decreased. FTIR, DSC , XRD, SEM, EDS, TEM, Raman, TGA, XPS, and NH 3 -TPD characterization techniques were utilized to fully analyze the DES, precursor and catalyst to explore MA selectivity. This work shifts the significant increase of 13% n-butane conversion, 11% MA selectivity and 16% MA mass yield, which greatly influences low carbon alkane utilization. Importantly, the CO: CO 2 ratio is reduced from 2.02 to 1.62, which is more beneficial for chemical plants as well as green environments.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
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