Friction
·
2023
·
IF 6.8
Yang Xiao,Wang Yunbo,Cao Weihua,Jiang Ruizheng,Xie Guoxin,Cao Yuying,Qi Xiaowen
To utilize Cu-benzene-1,3,5-tricarboxylate (Cu-BTC) adsorbed lubricant oils in the self-lubricating field, the adsorption properties of Cu-BTC on different 1-olefins must be clarified. In this work, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene were studied by the Monte Carlo method and experimentally. The adsorption limit of Cu-BTC for n-olefins was determined as 1-undecene by the adsorption isotherms. This suggested a limit for even straight-chain molecules to the adsorption of Cu-BTC. The maximum ratio of the olefin length of the largest pore diameter ( L / D ) of Cu-BTC was approximately 1.57. Furthermore, theoretical calculations (radial distribution function (RDF)) and experiments (infrared (IR) spectra) confirmed the interaction of n-olefin adsorbates and the Cu-BTC framework occurred between the -CH= of olefins and the Cu and O atoms of the Cu-BTC framework. This work adds to the understanding and investigation of the adsorption of liquid lubricants using Cu-BTC as a metal-organic framework (MOF).
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Catalysis Science & Technology
·
2022
·Vol. 12
·期 22
·6827-6837
·
IF 6.177
Penghui Li,Junhua Gao,Jing Shi,Huixiang Wang,Xiangying Xing,Jingzhao Ren,Yu Meng,Liancheng Wang,Baoliang Lv
Linear terminal olefin epoxidation is a significant oxidation reaction for the synthesis of valuable industrial intermediates. As typical olefin epoxidation catalysts, supported tungsten oxides are rich in oxygen vacancies, which have been investigated for improving catalytic performance in other reactions, but the influence on olefin epoxidation is rarely studied. Herein, a series of WO3−x/SBA-15 catalysts with different oxygen vacancy concentrations were obtained by impregnation and sequent hydrogen reduction at 300–600 °C. Their catalytic performances for 1-hexene epoxidation with hydrogen peroxide at 70 °C were studied. It was found that an appropriate concentration of oxygen vacancies could improve epoxidation (the epoxide productivity increased from 135 to 196 μmolepoxide gW−1 min−1) and reduce the apparent activation energy (from 51.6 to 46.9 kJ mol−1). The oxygen vacancies are also beneficial for cycloolefin and other linear olefin epoxidation. In particular, the productivity of cyclooctene oxide was promoted from 4161 to 5744 μmolepoxide gW−1 min−1. This promotion effect was attributed to the increase in the number of Lewis acid sites caused by introducing moderate oxygen vacancies, which could improve the activation of hydrogen peroxide and facilitate epoxidation. In situ FT-IR spectroscopy and density functional theory calculations further indicated that increasing the oxygen vacancies contributes to reducing the energy barrier of the transfer of electrophilic oxygen atoms in active intermediate W–OOH to 1-hexene, thereby promoting epoxidation.
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Materials Chemistry Frontiers
·
2022
·Vol. 6
·期 15
·2072-2084
·
IF 8.683
Yi Zhai,Fumin Wang,Xubin Zhang,Guojun Lv,Zhiguo Zhu,Kaiwei Wang,Zhibo Xu,Linfang Jiang
Realizing anatase-free hollow TS-1 with a controllable titanium micro-environment via dissolution-recrystallization for diverse catalytic reactions remains a great challenge due to the insufficient comprehension of dissolution-recrystallization mechanism, high cost and environmental issues. Here, anatase-free hollow TS-1 was economically synthesized via mother-liquor-induced dissolution-recrystallization, realizing the controllable micro-environment and spatial distribution of titanium. A novel kinetic-thermodynamic co-regulatory pathway was unveiled for the first time to describe the magical reversible varying of titanium micro-environment during the dissolution-recrystallization process (dissolution-reinsertion-secondary dissolution). Thermodynamically, temperature and liquid-to-solid ratio cause the formation of anatase and unsaturated silicon, and the unsaturated silicon species (Q1 and Q2) determine the subsequent capture and re-insertion of anatase. Original unsaturated silicon species in the mother liquor endow it with a unique function to further facilitate the elimination of anatase. Kinetically, temperature determines the dynamic progress of the reversible process such as evolution speed and deposition priority of titanium and silicon species. Multi-factor dynamic constraints directly determine the micro-environment, spatial distribution and content of titanium. This provides a new perspective for predicting and synthesizing hollow heteroatomic zeolites with ideal heteroatom micro-environments. Unique surface properties and diverse titanium micro-environments endow hollow TS-1 with superior mass-transfer abilities to exhibit different activities in 1-hexene epoxidation and phenol hydroxylation.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Guojun Lv,Yan Chen,Xuyang Zou,Jiangzhang Wang,Tao Wang,Fumin Wang,Xubin Zhang
Simultaneous insertion of double heteroatom in the MFI framework generally gives rise to synergistic catalysis effect, however the specific origins for synergistic catalysis is still nebulous. In this study, vanadium-titanium doped MFI zeolite was synthesized via one-pot hydrothermal synthesis with the addition of (NH 4 ) 2 CO 3 and applied as heterogeneous catalyst for the synergistic catalysis of 1-hexene and cyclohexene epoxidation. Simultaneous incorporation of vanadium and titanium induced the partial charge transformation of titanium (Ⅳ) into titanium (Ⅲ), which was verified by EPR and XPS characterizations. UV-Raman and UV–Vis spectra disclosed that partial charge transformation mainly occurred for framework titanium (Ⅳ). In addition, simultaneous insertion of vanadium and titanium gave rise to more Lewis acid sites as well as larger external surface area for VTS(0.15) zeolite in comparison to VS(0.15) and TS(0.15) zeolite. The prepared VTS(0.15) zeolite presented a TOF value of 118.8 h −1 for 1-hexene epoxidation, which is 7.8 folds and 1.3 folds of VS(0.15) and TS(0.15) respectively. Partial charge transformation of framework titanium (Ⅳ) into titanium (Ⅲ), robust Lewis acid sites as large external surface area may induce the synergistic catalysis effect for VTS(0.15) zeolite in the epoxidation reactions. Moreover, the obtained VTS(0.15) zeolite particles showed good reusability for more than five cycles.
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Lubrication Science
·
2022
·Vol. 34
·期 8
·527-536
·
IF 1.307
Jingze Cui,Qiong Tang,Chen Chen,Hong Xu,Lei Liu,Jinxiang Dong
Producing lubricating base oils from coal-based chemicals is an alternative route for replacing the conventional petro-based lubricants. Herein, we firstly reported the synthesis of high-viscosity polyalkylphenanthrene oils derived from the coal-based chemicals (phenanthrene, C6/C8-olefins) by alkylation with acidic ionic liquid (Et 3 NHCl∙2AlCl 3 ) as catalyst. Their primary physicochemical properties were studied in detail to reveal their structure–property relationships, the existence of the phenanthrene ring in their molecular structure led to some good property, such as high-kinematic viscosity (12.6–30.2 mm 2 ·s −1 at 100°C), better flash point (>230°C), high-oxidative onset time (>230°C) and good polarity. Moreover, the tribological performances of the synthetic oils and the commercial PAO-20 lubricating base oil were studied for comparison, these alkylated phenanthrenes, especially PHP-3 and POP-3, exhibited much higher load-carrying capacity, reducing friction and anti-wear property than that observed on PAO-20.
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CATALYSIS LETTERS
·
2022
·Vol. 153
·期 4
·1180-1192
·
IF 2.936
Xing Xiangying,Wang Huixiang,Shi Jing,Li Penghui,Ren Jingzhao,Wang Liancheng,Zhang Jianli,Liu Zhong,Lv Baoliang
WO x has good performance in olefin epoxidation, however, the presence of a large amount of Brönsted acid on WO x affects the selectivity of epoxy products. In this paper, broken carbon spheres ( b-C spheres) treated with nitric acid were used as support to anchor WO x in dynamic solvothermal process. Based on GC–MS and GC-IR detection, the obtained WO x /C greatly increased selectivity of 1,2-epoxyhexane from 16.0% ( pure WO x ) to 92.1% in epoxidation of 1-hexene. The improvement of WO x performance is attributed to the reduction of Brönsted acid sites and electron cloud density after loading, which may all result from interaction between WO x and oxygen-containing functional groups of b-C spheres. Above changes not only effectively inhibit the hydrolysis of 1,2-epoxyhexane, but also are conducive to nucleophilic reaction of H 2 O 2 to WO x, which is beneficial to the activation of H 2 O 2 . Finally, an epoxidation mechanism with oxygen vacancies as the main route under WO x /C catalysis is reasonably proposed. Graphical Abstract
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FUEL PROCESSING TECHNOLOGY
·
2022
·
IF 8.129
Xin Ning,Junwen Chen,Qi Zuo,Wenlin Li,Jiajun Zheng,Ruifeng Li
Light alkenes oligomerization , performed in the presence of solid acid catalysts , is an important alternative for the production of clean jet fuels. For 1-hexene oligomerization, the current catalyst often suffers from low activity and selectivity. The developed process is upgraded by zeolite catalyst, targeting high-concentration of jet-range hydrocarbons. An efficient and selective IM-5 zeolite-derived catalytic system has been developed for the oligomerization of 1-hexene. The treatment in an aqueous NH 4 F solution led to dealumination without structure degradation. The IM-5 zeolite with a unique two-dimensional IMF structure and 2.5 nm nanoslab showed rapid diffusion ability than ZSM-5 zeolite. Enhance acidities were observed in the NH 4 F-treated IM-5 zeolites owing to fluoride residue and the removal of Al atoms. The strong Brønsted acid sites exerted a positive effect on both the cracking and the oligomerization reactions with the increasing of the yields of dimers. The contact time and partial pressure between the 1-hexene and the IM-5 zeolites were used to analyze the competition of cracking reactions. High 1-hexene conversion (62%), optimal oligomerization to C 3 -C 5 ratio (O/C = 32), and reasonable stability were obtained over the etched IM-5 catalyst at 240 °C, 4 MPa, and the flow rate of N 2 was 50 mL/min.
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TENSIDE SURFACTANTS DETERGENTS
·
2022
·Vol. 59
·期 1
·39-50
·
IF 1.058
Fuwen Tan,Xu Li,Jinxiang Dong
Fischer-Tropsch syncrude prepared via the Fischer-Tropsch synthesis (FTS) using a Fe-based catalyst is featured by its high content of linear α-olefins (C 5 –C 13 ). The utilization of C 6 –C 8 α-olefins for the synthesis of alkyl benzene sulfonate surfactants was performed in the present work via dimerization, benzene alkylation, and sulfonation. The effects of the reaction conditions on benzene alkylation over a trimethyl amine hydrochloride-acidic anhydrous aluminum chloride ionic liquid catalyst (Et 3 NHCl-AlCl 3 ) have been studied in detail using C 6 α-olefin dimers as a model alkylation agent. Under the optimal reaction conditions (molar ratio of AlCl 3 to Et 3 NHCl = 2, catalyst loading = 0.29 mol %, reaction temperature = 30 °C, and molar ratio of benzene to C 6 α-olefin dimer = 10) the conversion of the C 6 α-olefin dimer was 100% and the selectivity toward the mono alkylbenzene product was 91.0%. C 6 –C 8 α-olefin dimer alkylbenzene sulfonates (C 6 –C 8 DBS) were synthesized via sulfonation using chlorosulfonic acid and characterized using Fourier Transform Infrared (FT-IR) spectroscopy and Liquid Chromatography–Mass Spectrometry (LC–MS). The surfactant properties of the C 6 –C 8 DBS, including their equilibrium and dynamic surface tension, foaming, wetting and emulsifying capabilities, were closely explored and compared with a commercial linear alkylbenzene sulfonate (LAS). The limiting surface tension ( γ
CMC = 34.62 mN m −1 ) and critical micelle concentration (CMC = 2.15 mmol L −1 ) of C 6 α-olefin dimer alkylbenzene sulfonate (C 6 -DBS) were similar to those of LAS. Upon increasing the hydrocarbon chain length, the γ
CMC of C 6 -DBS, C 7 -DBS, and C 8 -DBS remained unchanged, while the CMC decreased. C 6 –C 8 -DBS exhibited foaming, emulsifying, and wetting properties comparable to LAS.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2022
·Vol. 36
·期 6
·e6648
·
IF 4.072
Zehao Yu,Zijie Song,Chunshan Lu,Ying Bai,Jiayun Li,Jun Liu,Peng Liu,Jiajian Peng
Hydrosilylation employing metal–organic frameworks (MOFs) as the catalyst are promising because of their high catalytic reactivity and sustainability of heterogeneous catalyst. A highly simple and efficient method for the hydrosilylation of olefins catalyzed by an air-stable MOF-cobalt catalysts is developed. This approach is featured by 0.1% of Co-MOFs catalyst with excellent reactivity, recyclability, and good functional group tolerance. The Co-MOFs can catalyze hydrosilylation of styrene or its derivatives with Ph 2 SiH 2 in the presence of NaBHEt 3 . Moreover, the catalysts we developed show excellent stability, and the activity is not significantly reduced after repeating the cycle for five times.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Yongkui Liu,Fumin Wang,Xubin Zhang,Qing Zhang,Yi Zhai,Guojun Lv,Mengyao Li,Mengyue Li
Development of economic routes for synthesis of hollow titanium silicalite-1 (TS-1) zeolite is of great importance in industry. However, there are still challenges to synthesize hollow TS-1 zeolite without anatase TiO 2 . In this work, a one-step strategy without mesoporogen by the solid-phase conversion method was successfully developed to synthesize anatase-free hollow TS-1. The appropriate low amount of TPAOH (TPA/SiO 2 = 0.13) and the suitable crystallization temperature (170 °C) can not merely induce the formation of hollow structures, but also enable more titanium to enter the framework. Moreover, the transformation mechanism based on crystallization rate and dissolution rate was proposed according to the investigation of the transformation process. The hollow TS-1 with large cavities exhibits high catalytic activity and recycle stability in 1-hexene epoxidation. The efficient strategy reported in this paper will provide new opportunities for further promoting the industrial application of hollow TS-1.
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JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Zhihong Lin,Ziyi Yuan,Kaifang Wang,Xuezhong He
Novel mixed matrix membranes (MMMs) with superior CO 2 /N 2 separation properties are of great importance for post-combustion CO 2 capture from flue gas . Metal-organic frameworks (MOFs) as one of the most attractive porous fillers for MMMs fabrication, are considered to provide a solid molecular sieving mechanism for enhancing CO 2 /N 2 selectivity. However, it causes the reduction in gas permeability and limits its further industrialization. Herein, we proposed a new strategy for filler functionalization by doping silver ions (Ag + ) into UiO-66-NH 2 nanoparticles through the double-solvent method and used for the preparation of advanced MMMs. The double-solvent method is benefits for the enrichment of Ag + in the hydrophilic pores of UiO-66-NH 2 . As a result, the prepared novel MMMs called Ag + @UiO@PIM-1 with the polymers of intrinsic microporosity (PIMs) as polymer matrix , show outstanding CO 2 permeability. According to the mixed gases (CO 2 /N 2 = 10:90) permeation experiments under 25 °C and 2 bar, the membrane with 30%Ag + @10%UiO loading achieves more than 65% increase in CO 2 /N 2 selectivity (∼30) and 120% in CO 2 permeability (>15,000 Barrer) compared to the pristine PIM-1 membrane. By optimizing the Ag + doping amount and Ag + @UiO loading content, the separation performance exceeds the 2019 CO 2 /N 2 upper bound. To figure out the separation mechanism, the pore texture properties and CO 2 affinity of the functional filler (Ag + @UiO) together with the membrane structure were characterized by XPS , PXRD , SEM, gas sorption , etc. The synergistic mechanisms by combing CO 2 facilitated transport and molecular sieving from pore regulation were identified to enable advanced CO 2 /N 2 membrane separation .
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Nature Communications
·
2023
·Vol. 14
·期 1
·1-9
·
IF 16.6
Liu Yifeng,Liu Zhiqiang,Hui Yu,Wang Liang,Zhang Jian,Yi Xianfeng,Chen Wei,Wang Chengtao,Wang Hai,Qin Yucai,Song Lijuan,Zheng Anmin,Xiao Feng-Shou
Hydroformylation is one of the largest industrially homogeneous processes that strongly relies on catalysts with phosphine ligands such as the Wilkinson’s catalyst (triphenylphosphine coordinated Rh). Heterogeneous catalysts for olefin hydroformylation are highly desired but suffer from poor activity compared with homogeneous catalysts. Herein, we demonstrate that rhodium nanoparticles supported on siliceous MFI zeolite with abundant silanol nests are very active for hydroformylation, giving a turnover frequency as high as ~50,000 h −1 that even outperforms the classical Wilkinson’s catalyst. Mechanism study reveals that the siliceous zeolite with silanol nests could efficiently enrich olefin molecules to adjacent rhodium nanoparticles, enhancing the hydroformylation reaction.
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