CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2021
·
IF 3.171
Xiaocheng Lin,Youjie Huang,Ling Li,Changshen Ye,Jie Chen,Ting Qiu
A series of polymeric ionic liquids (PILs) used as effective heterogeneous catalysts for biodiesel production via esterification of free fatty acids (FFAs) were effectively prepared by the reaction of poly (ethylene imine) (PEI) polymers with different molecular weight and 1,3-propanesultone, followed by the further acidification with differential effective acids, i.e. H 2 SO 4 , CF 3 SO 3 H, CH 3 SO 3 H or p -toluenesulfonic acid ( p -TSA). Ultrahigh acidity and catalytic performance were achieved and could be fine-tuned by simply adjusting the molecular weight of PEI and by further treatment of acids. Specifically, under the optimal conditions ( i.e. reaction temperature was 70 °C, reaction time was 2.0 h, catalyst dosage was 3.15% (mass), and alcohol/acid molar ratio was 14:1) acquired through the Box-BEHNKEN response surface methodology, a high oleic acid conversion of 98.42% could be obtained over the optimal PIL, PEI(70000)-PS- p -TSA. Additionally, our PILs also showed high generality for esterification of other FFAs, with general high conversion over 90% noted in each case even under much milder reaction conditions compared to other conventional catalysts.
研究领域:
化学工程
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可再生能源
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产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Xiaochao Xian,Mengjun He,Yakai Gao,Yi Bi,Yirong Chu,Jun Chen,Lichun Dong,Jin Wang,Shuo Zhao
Reducing the acid density and strength of HZSM-5 zeolite are typical strategies to inhibit coke deposition during catalytic cracking reactions. Herein, direct titration of HZSM-5/H 2 O suspension using dilute NaOH aqueous solution at room temperature was introduced to neutralize excessive Brønsted acid sites of HZSM-5 zeolite (Si/Al = 25). SEM, XRD, N 2 adsorption and n -propylamine temperature-programmed decomposition confirmed that simultaneous acid strength weakening and acid density reducing were achieved without obvious influence on crystalline or textural property. The evolution of the surface charge during the titration process tracked by Zeta-potential measurement reveals that the mechanism of such neutralization is: liquid phase neutralization between H + and OH − & solid phase ion exchange between Na + and H + . Supercritical catalytic cracking of n -dodecane over a series of partial neutralized HZSM-5 catalysts showed that moderate neutralization can enhance the conversion of n -dodecane by alleviating both the coke amount and harmfulness per unit mass of coke.
研究领域:
化学工程
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催化材料
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 20
·6268-6284
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IF 6.177
Tingyu Liang,Jialing Chen,Sen Wang,Pengfei Wang,Zhangfeng Qin,Fang Jin,Mei Dong,Jianguo Wang,Weibin Fan
A series of H-MCM-22 zeolites with different Si/Al ratios (H-M22-x, x = 15–90) were hydrothermally synthesized by boron incorporation to investigate the influences of acid density on the methanol-to-hydrocarbon (MTH) performances and deactivation behaviors. The acid density of H-M22-x zeolites is nearly proportional to their aluminum contents; the residual boron barely affects the overall acidity of H-M22-x zeolites. 27Al and 29Si MAS NMR experiments support the existence of competitive occupancy of various framework T sites among boron, aluminum and silicon during zeolite synthesis, which leads to different distribution of Brønsted acid sites/framework aluminum among three types of pores in H-MCM-22 zeolites. Increasing the Si/Al ratio of H-M22-x zeolites leads to a gradual increase in the proportion of Brønsted acid sites in supercages while those in sinusoidal channels decrease. However, the acid density has a significantly larger impact than acid distribution on the MTH performances of H-M22-x zeolites. Increasing the acid density can accelerate the hydrogen transfer reactions in the MTH conversion and promote the formation of aromatics, ethene, and alkanes. The deactivation of H-M22-x zeolites with low acid density (x = 50–90) is mainly ascribed to coke covering the acid sites inside the micropores and partly blocking the pore mouths. Nevertheless, the deactivation of H-M22-x zeolites with high acid density (x = 15–30) is mainly caused by massive coke deposition on the external surface which blocks the pore mouths of inner micropores. The coke on the external surface exhibits a lower decomposition temperature than that inside the micropores. The deactivation behaviors of H-M22-x zeolites for the MTH reaction can be divided into three stages. Firstly, rapid deactivation of supercages occurred for all the H-M22-x zeolites in spite of their different acid densities, suggesting a much stronger influence of pore structure than acidity on the initial deactivation behaviors of H-M22-x zeolites. Secondly, the acid sites in sinusoidal channels of H-M22-x zeolites are highly resistant to coke formation, which dominates the MTH reaction in the second stage. Finally, with the continuous formation of coke in the surface pockets, which gradually covers the acid sites and pore mouths of sinusoidal channels, complete deactivation of H-M22-x zeolites can be observed. GC-MS and UV-vis analysis of partly or completely deactivated H-M22-x zeolites reveals that the retained species in H-M22-x zeolites gradually condense into bulky hydrocarbon species through successive hydrogen transfer reactions and form methylbenzenes, naphthalene, polymethylnaphthalenes, phenalenone, pyrenes and eventually graphite-like carbonaceous species.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Sustainability
·
2023
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IF 7.8
W. Dai,L. Zhang,R. Liu,Z. Huo,W. Dai,N. Guan
Zeolite catalysts with high propylene selectivity and superior stability are highly desirable in the methanol to propylene (MTP) conversion. Herein, plate-like MFI zeolites with different Si/Al (Ga) ratios were successfully prepared via a fluoride assisted strategy and applied in the MTP reaction. The influences of the zeolite morphology, acid density, and strength on the MTP activity as well as the reaction mechanism were clarified by combining spectroscopic and catalytic results. The plate-like MFI zeolites with lower acid density could efficiently suppress the aromatic-based cycle and promote the olefin-based cycle and thus exhibited a remarkable catalytic performance in the MTP conversion. However, owing to occurrence of irreversible hydrolysis of the Si-OH-Ga group during the MTP conversion, the catalytic activity of the Ga-MFI catalyst was not recyclable. On the contrary, the plate-like ZSM-5 catalyst shows excellent stability and recyclability in the MTP conversion.
研究领域:
催化化学
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能源化工
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材料科学
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石油化工
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工业催化
✓ 已验证
DOI
高影响因子
LANGMUIR
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2015
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IF 4.457
Xiujuan Shi,Wenjun Zhan,Gaojian Chen,Qian Yu,Qi Liu,Hui Du,Limin Cao,Xiaoli Liu,Lin Yuan,Hong Chen
The protein binding capability of biomaterial surfaces can significantly affect subsequent biological responses, and appropriate ligand presentation is often required to guarantee the best functions. Herein, a new facile method for regulating this capability by varying the localized and average ligand density is presented. Binding between lysine and plasminogen relevant to a fibrinolysis system was chosen as a model. We integrated different lysine-modified β-cyclodextrin (β-CD) derivatives onto bioinert copolymer brushes via host–guest interactions. The localized and average lysine density can be conveniently modulated by changing the lysine valency on β-CD scaffolds and by diluting lysine-persubstituted β-CD with pure β-CD, respectively. Both the plasminogen adsorption and the plasminogen binding affinity were enhanced by lysine-persubstituted β-CD compared with those of lysine-monosubstituted β-CD, which is possibly due to the higher localized lysine density and the multivalent binding of plasminogen on lysine-persubstituted β-CD surfaces. With a change in the ratio of lysine-persubstituted β-CD to β-CD, the average lysine density can be tuned, leading to the linear regulation of the adsorption of plasminogen on surfaces.
研究领域:
生物材料学
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分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
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2024
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IF 6.7
Zhuo Wang,Huiling Zheng,Fanhui Meng,Tingjun Fu,Zhong Li
The use of ZSM-5@Zn/ZSM-5 core@shell nanocrystals as integrated catalyst for efficient aromatic production from methanol aromatization is demonstrated. By combining the attributes associated with core@shell structural and acidic features, ZSM-5@Zn/ZSM-5 exhibited synergistic and improved catalytic performance toward methanol aromatization. The effect of Zn/ZSM-5 shell thickness and the acid density of the ZSM-5 core on synergistic performance was systematically investigated. Results showed that aromatic selectivity could be increased with shell thickness and the acid density of the ZSM-5 core, while catalytic stability was subject to the optimization on both shell thickness and core acid density. The strengthening of dehydroaromatization on the shell catalyst after Zn introduction and the hydrogen transfer for aromatization with increasing core acid density was confirmed. A double boost on catalytic stability from methanol conversion along with 40.7% increase on aromatic selectivity could be achieved for core@shell catalyst with a coating ratio of 0.3 compared with that on single core catalyst. The fabrication of ZSM-5 core with low SiO 2 /Al 2 O 3 ratio for Zn/ZSM-5 not only provided more acid sites to promote the aromatization, but also promoted the dealkylation of the formed aromatics, which could enhance the selectivity of light aromatics and catalytic lifetime. The findings in the work not only enrich the family of core@shell composite zeolite catalysts, but also provide the fundamental understanding on the aromatization process over core@shell structural features.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
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2018
·Vol. 44
·期 9
·5439-5453
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IF 1.674
Huang Feng,Li Wenzhi,Zhang Tingwei,Li Dawei,Liu Qiyu,Zhu Xifeng,Ma Longlong
A carbonaceous solid acid catalyst with high strong-acid density was synthesized by facile functionalization of a biomass-derived mesoporous carbon with benzenesulfonic acid. The catalyst was characterized by using Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, and N 2 adsorption–desorption. The carbonaceous solid catalyst containing Brønsted acid sites was used for the production of 5-hydroxymethylfurfural (HMF) from hexoses such as fructose, glucose, and cellulose in γ-valerolactone (GVL)-H 2 O mixture. By reaction at 130 °C for 20 min using fructose as a feedstock, an HMF yield 78.1% was achieved. The catalytic performance of the catalyst in conversion of fructose into HMF hardly changed over seven cycles, demonstrating that the catalyst had excellent recyclability. The yields of HMF derived from glucose and cellulose reached 33.2 and 22.5%, respectively, whereas those of total furans were 42.1 and 33.7%, respectively. The proposed reaction system was promising in transforming biomass-based carbohydrates into fine chemicals, given the use of green functionalization methods, the utilization of sustainable biomass-derived carbon precursor and solvents, catalyst with high acid density, and the availability of high HMF yield.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
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2022
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IF 4.05
Liang Chen,Du Chunhua,Wu Xianli,Wang Ju,Xu Jie,Hu Pengyu,Qu Wangda
In order to enhance the valorization of corncob, corncob-based solid acid catalysts were prepared via the method of partial carbonization followed by sulfonation. The prepared acid catalysts were either derived from raw corncob (hemicellulose, cellulose, and lignin), or its residues after different pretreatments, i.e., furfural residue (cellulose and lignin) and hydrolysis residue (humins and lignin), to investigate the components’ effect on the performance of solid acid. These catalysts were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nitrogen adsorption/desorption analysis, scanning electron microscope (SEM), elemental analysis, and acid–base titration. The analysis results suggested that the solid acid (Catalyst-3) derived from the hydrolysis residue had the best performance, with a BET surface area of 338.23 m 2 g −1 and total acid densities of 6.43 mmol g −1 . This results indicated –SO 3 H groups were loaded onto the catalyst successfully. The catalytic activity was tested by cellulose hydrolysis in lithium bromide trihydrate solution (LBTH) system. The yield of glucose was as high as 80.1% at the temperature of 110 °C for 10 h. Moreover, the prepared solid acid had the advantages of easy separation, mild reaction, and producing less by-products compared with traditional liquid acids. This work provides a promising strategy for corncob waste utilization and cellulose efficient hydrolysis, which is of great significance for biomass valorization and conversion.
研究领域:
化学工程
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材料科学
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生物技术
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
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2025
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IF 4.9
Qian Li,Liang Gao,Hao Zou,Yibin Luo,Xingtian Shu,Hao Wang
The dehydration-Prins condensation of tert‑butanol (TBA) and paraformaldehyde to produce 4,4-dimethyl-1,3-dioxane (DMD) was investigated using Hβ zeolites with a controlled Si/Al ratio. The acidic properties, including type, strength, and density, were systematically characterized, revealing that both total acid density and weak Brønsted acid density critically govern DMD selectivity. Specifically, reducing the weak Brønsted acid density from 204.91 to 92.94 μmol/g resulted in an 18 % decrease in DMD selectivity. Reaction pathway analysis identified the dehydration of TBA to isobutene as the key initial step. Furthermore, the introduction of extra-framework aluminum species enhanced the Lewis acid density and the Brønsted-to-Lewis (B/L) acid ratio. TBA dehydration experiments confirmed that Lewis acids originating from extra-framework aluminum significantly promote this critical step. Under the optimized conditions of 125 °C, 3.0 MPa, 0.417 mol of paraformaldehyde, 0.208 mol of TBA, 20 wt % H 2 O, and 1.7 wt % Hβ22, the conversion of TBA reached 59.1 %, the selectivity for DMD was 57.3 %, and the main by-product was identified as an over-condensation product with a 1,3-dioxane structure.
研究领域:
催化化学
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有机化学
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物理化学
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材料科学
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化学反应工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
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IF 6.7
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao
The application of non-noble metal supported catalysts in the hydroisomerization of long-chain n-alkanes is a novel field, and there is currently not any research available on the deactivation process of these catalysts. We investigated into the deactivation mechanism of NiWS/SAPO-11 catalyst in the hydroisomerization of n-hexadecane in this work for the first time. Specifically, coke deposition behavior and active phase migration were investigated. The reduction of catalytic efficiency of the catalyst was partially aided by the decrease in specific surface area, pore volume, and acid density. From the perspective of the active phase, the clusters of NiWS active phase migrated as the reaction time increased, mostly resulting in an increase in both the stacking number and the length of active phase slabs. The migration of active phase increased the distance between active phase clusters and metal sites, and decreased the utilization ratio of active metal atoms. From the perspective of coke deposition, the coke formed on the catalyst includes soft coke and hard coke. The formation and evolution of coke on the catalyst were investigated. The soft coke (aliphatic compounds) progressively transformed into hard coke (polycyclic aromatic hydrocarbons and graphite-like), and the coke gradually migrated from the external surface of the catalyst to the pore channels as the reaction time increased. It is expected to provide theoretical basis and reference value for the deactivation research and design of non-noble metal supported hydroisomerization catalyst.
研究领域:
催化
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化学工程
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石油化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
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2024
·Vol. 29
·期 12
·2752
·
IF 4.2
Zhimin Yang,Yu Wang,Xichang Wu,Wenxuan Quan,Qi Chen,Anping Wang
This study prepared sulfonatedCamellia oleiferashell biochar usingCamellia oleiferashell agricultural waste as a carbon source, and evaluated its performance as a catalyst for preparing biodiesel. The biochar obtained from carbonizingCamellia oleiferashells at 500 °C for 2 h serves as the carbon skeleton, and then the biochar is sulfonated with chlorosulfonic acid. The sulfonic acid groups are mainly grafted onto the surface ofCamellia oleiferashell biochar through covalent bonding to obtain sulfonic acid type biochar catalysts. The catalysts were characterized by Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Nitrogen adsorption-desorption Brunel-Emmett-Taylor Theory (BET), and Fourier-transform infrared spectroscopy (FT-IR). The acid density of the sulfonatedCamellia oleiferafruit shell biochar catalyst is 2.86 mmol/g, and the specific surface area is 2.67 m2/g, indicating high catalytic activity. The optimal reaction conditions are 4 wt% catalyst with a 6:1 alcohol to oil ratio. After esterification at 70 °C for 2 h, the yield of biodiesel was 91.4%. Under the optimal reaction conditions, after four repeated uses of the catalyst, the yield of biodiesel still reached 90%. Therefore, sulfonatedCamellia oleiferashell biochar is a low-cost, green, non-homogeneous catalyst with great potential for biodiesel production by esterification reaction in future development.
研究领域:
生物化学
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环境科学
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化学工程
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可再生能源
✓ 已验证
DOI
PubMed
高影响因子
Reaction Chemistry & Engineering
·
2023
·Vol. 8
·期 11
·2738-2745
·
IF 3.9
Haoran Yuan,Chengyu Li,Rui Shan,Jun Zhang,Yong Chen
A series of antibiotic residue derived solid acids were developed for the selective transformation of bio-based furfuryl alcohol into ethyl levulinate. KOH modification and chlorosulfonic acid decoration of gentamicin residue derived carbon materials played a crucial role in ethyl levulinate production. Various characterization methods were employed for unveiling the structural information regarding porous characteristics and functional groups, such as FT-IR, N2 adsorption–desorption, SEM, etc. The yields of 2-(ethoxymethyl)furan and ethyl levulinate were particularly associated with the acid density of gentamicin residue derived solid acids. Gratifyingly, a maximum ethyl levulinate yield of 84.5% was achieved at 160 °C after 1.5 h. The recovery and reutilization of the catalyst in successive reactions demonstrated that gentamicin residue derived solid acids maintained good activity and stability even after four cycles. The present research thus highlights a novel direction for high-value utilization of antibiotic residues as well as the synthesis of platform chemicals over organic waste derived catalytic materials.
研究领域:
化学工程
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催化
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材料科学
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环境科学
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生物化学
✓ 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）