Lubrication Science
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2022
·Vol. 35
·期 1
·1-13
·
IF 1.307
Chao Ju,Qin Zhao,Xiaobo Wang
A series of protic ionic liquids (PILs) containing dibutyldithiophosphate were simply synthesised and used as lubricant additive in base emulsion. The physico-chemical and lubricating properties of PILs in emulsion were systematically investigated. The stability of prepared emulsions containing PILs were similar with base emulsions by particle size distribution tests. Compared with traditional additive of polysulfide, the PILs in emulsion exhibited superior lubricating properties under harsh conditions. Surprisingly, the oil-miscible O-PILs in emulsion showed better friction and wear reduction than water-miscible T-PILs in emulsion. The stable protective films formed on the steel surface by results of scanning electron microscope and X-ray photoelectron spectroscopy were the main reason for the preferable performance.
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ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Jinhui Chen,Qinqin Xu,Feng He,Wang Yue,Gang Hu,Jianyun Gan,Haibo Xie
Economically competitive and sustainable dissolution pretreatment technology is in high demand due to the remarkable achievement in the pretreatment of lignocellulose using ionic liquids (ILs) for enhanced enzymatic hydrolysis. Herein, levulinic acid (Lev), a well-known bio-based platform chemical derived from carbohydrates, in conjunction with a series of organic superbases, was used as a raw chemical to prepare a new class of protic ILs (PILs). The findings indicated that the obtained PILs exhibited a good solubility of up to 10 wt % toward corn stover-based lignocellulose at 140 °C in 40 mins, based on which a facile and efficient dissolution pretreatment technology was developed for enhanced enzymatic hydrolysis of corn stover. The facile dissolution and regeneration of corn stover resulted in significant changes in the composition and physical–chemical structures. These changes led to significantly enhanced enzymatic hydrolysis behavior of the pretreated sample with total reducing sugar and glucose yields of 0.8 and 0.49 g/g within 48 h under optimal conditions, respectively. The Kamlet–Taft solvent parameters of the PILs were systematically evaluated, and the interaction between the lignocellulose and PILs was studied by 13C NMR, indicating that the satisfactory performance of PILs was benefited from the higher ß parameter value and the stronger interactions, particularly the existence of the extra hydrogen-bond interaction from the potential keto–enol tautomerism of the ketone groups in levulinate anions. The compositional and physicochemical changes in the lignocellulose were systematically evaluated to achieve an in-depth understanding of the dissolution activation mechanism using various characterization techniques. The findings also showed that 44.3% of lignin could be fractionated during the facile dissolution and regeneration process, together with a transformation of the crystalline structure of cellulose I to cellulose II and of the packed morphology to a porous one. The structure of the fractionated lignin was also characterized for a better understanding of the fractionation process. The study demonstrated a new sustainable dissolution pretreatment technology for enhanced enzymatic hydrolysis, which can provide significant insights into the design of new solvents for biomass dissolution and processing.
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JOURNAL OF MOLECULAR LIQUIDS
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2022
·
IF 6.633
Shuang Li,Shenyi Jiang,Pingbo Zhang,Pingping Jiang,Yan Leng
Trimethylolpropane acrylate (TMPTA) is becoming an important organic chemistry intermediate, but it’s synthesis through the acid-catalyzed esterification of trimethylolpropane and acrylic acid is a challenge due to the poor activity and catalyst separation problems. In this work, a series of 1,3-propanesultone (PS)-functionalized imidazole ionic liquids (ILs) are prepared and evaluated as the acid catalysts for this reaction, including the catalytic performance comparison, optimization of reaction conditions, and the catalytic reusability. The obtained H 2 SO 4 -based IL ([IMPSH]HSO 4 ) caused a phase-separation catalytic process (reacted as a homogeneous catalyst, but precipitated at the end of reaction like a heterogeneous catalyst), presenting the best trimethylolpropane conversion (100%) and TMPTA selectivity (86.4%). Such catalytic performance is even better than that of homogeneous H 2 SO 4 . Moreover, the catalyst can be steadily reused at least four times without obvious change in activity and its structure. The highly efficient and environmentally benign performance of [IMPSH]HSO 4 -catalyzed esterification of trimethylolpropane and acrylic acid make it possible to achieve industrial applications.
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APPLIED CLAY SCIENCE
·
2022
·
IF 5.907
Yang He,Lihua Zhou,Shaohua Gou,Xiaolin Qian,Zhihao Tian,Junwen Chen,Jie Liao,Jing Huo,Guangjun Gou
The imidazolium Gemini ionic liquids (IL), with alkyl groups ranging from butyl to tetradecyl as tail chains and polyoxyethylene group as linker chain, were synthesized and used as novel efficient modifiers for flexibly controlling the swelling and dispersion of Na-montmorillonite (Na Mt). The correlation between swelling behavior and structure of imidazolium Gemini IL was investigated. Too long or too short tail chains caused greater swelling, obtaining smaller particle size and reductive face-to-face stacking degree of layers. Based on the change of water contact angles, the increased stability of modified Mt in water indicated that the hydrophobicity of the tail chains played an important role in impeding the entry of water molecules into the interlayer . Zeta potential , Fourier transform infrared spectra and X-ray photoelectron spectroscopy validated the cation exchange between imidazolium Gemini IL and Na + , and confirmed the adsorption site. The molecular arrangement and intercalation were determined through adsorption behavior , interlayer space of Mt and simulation of molecular size. The imidazolium Gemini IL covered the Mt layers in monolayer, finally taking lateral (short tail chains) or paraffin (long tail chains) arrangement. The investigation will provide useful guidance for modifying Mt to obtain desirable properties and broadening the practical application of Mt hybrids.
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Reaction Kinetics Mechanisms and Catalysis
·
2022
·Vol. 135
·期 2
·795-810
·
IF 1.843
Liu Panli,Shi Shengbin,Gao Lijing,Xiao Guomin
In the present work, three immobilized imidazolium acidic ionic liquid catalysts (ImmHSO 4 -IL, ImmCH 3 SO 3 -IL and ImmH 2 PO 4 -IL) were prepared with silica as carrier and modified with H 2 SO 4 , CH 3 SO 3 H and H 3 PO 4 , which were used as catalysts in the production of furfural from xylan and rice husk. The characteristics of the synthesized catalysts were analyzed by various characterization techniques, and the effects of reaction conditions, including reaction solvent, reaction time, reaction temperature and the amount of catalyst on the yield of furfural were studied in detail. The results showed that the highest yield of furfural reached 72% and 74.6% when using xylan and rice husk as substrates, respectively, which is one of the best furfural yield among literature reports. In addition, the ImmHSO 4 -IL catalyst has excellent selectivity for hemicellulose in rice husk, and the catalyst has high catalytic activity after four cycles. Therefore, the application of ImmHSO 4 -IL catalyst provides a new approach for conversion biomass to furfural. Graphical abstract
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高影响因子
FUEL
·
2023
·
IF 7.4
Ping An,Jian Shi,Yuxin Wang,Zizhen Yan,Jiaxiang Hou,Guangwen Xu,Haiming Yu,Lei Shi
Various strongly basic ionic liquids with distinctive structures, including single and double ended quaternary ammonium and phosphorus salts, were first synthesized based on hydroxyethoxy anion (HOCH 2 CH 2 O – ) from the product ethylene glycol . Nature was characterized by NMR, FTIR, TG and acid-base titration. Its alkali strength was equivalent to that of sodium methoxide, demonstrating superior alkalinity. Influences of cation structures and C 1 -C 4 alcohols structures on transesterification efficiency were investigated. Under mild conditions (68 °C for 5 min), DMC yield was 42.8% with a TOF value of 2853.6 h −1 when [TBAB]OCH 2 CH 2 OH as catalyst with only 0.18% EC molar content, indicating good catalytic performance. Comparison was made for reaction results between the synthesized catalysts and reported catalysts in literatures. The reaction mechanism was further deduced. Activation energies of positive and reverse reactions were determined as Ea + =32.0 kJ·mol −1 and Ea - =15.3 kJ·mol −1 through kinetics calculation. Relying on its decomposability and recyclability of decomposition products, a new catalyst circulation process without introducing any impurities was proposed and verified.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 14
·51903
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IF 3.125
Liurong Huang,Shuang Ding,Tian Chen,Ruike Wu,Xinyu Wang,Shifang Jia
This paper explores the structural and functional properties of collagen from tilapia scales pretreated by heat-assisted ionic liquids (ILs). Results show that the solubility of collagen was significantly influenced by the type and concentration of ILs. With the increase of IL concentration, a remarkable decrease in solubility of collagen was seen. Fluorescence spectra show that heat and IL pretreatments induced the exposure of chromophores. Changes in sodium dodecyl sulfate–polyacrylamide gel electrophoresis indicated that subunits of collagen regenerated from most of the IL solvent systems were not destroyed. The functional properties of regenerated collagen were evaluated by gel strength, viscosity, water-binding capacity, and emulsifying capacity. Results show that all heat-assisted ILs pretreatments improved the gel strength and viscosity, and the highest gel strength and viscosity were both obtained in the collagen pretreated by heat-assisted [EMIM]Cl. Heat-assisted [BMIM]BF 4 pretreatment exhibited the lowest water-binding capacity. Heat-assisted [BDMIM]Cl pretreatment indicated superior effect on improving emulsifying capacity than other pretreatments due to its ability to break most of the hydrogen bonds in collagen molecules, resulting in the formation of new re-aggregates with higher solubility and more hydrophobic groups.
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Reaction Kinetics Mechanisms and Catalysis
·
2021
·Vol. 134
·期 2
·823-835
·
IF 2.081
Wang Ying,He Runfa,Wang Cong,Li Gang
A kind of heterogeneous catalyst MCM-41-S-ImBr was prepared by grafting 1-vinyl-3-ethylimidazolium bromide ([VEIM]Br) on the surface of MCM-41. The catalyst was characterized by X-ray diffraction patterns, Fourier transform infrared spectroscopy and element analysis as well as scanning electron microscopy. It showed that [VEIM]Br was successfully grafted on MCM-41 and the catalyst possessed an average particle size of 1.4 µm with intact mesoporous structure. Moreover, the catalyst exhibited high catalytic activity in the cycloaddition reaction of CO 2 with epichlorohydrin without co-catalyst. The conversion of epichlorohydrin was 98.5% and the selectivity of cyclic carbonate was 98.3% at 130 °C under 1.6 MPa for 6 h. Reaction kinetic study indicated that the pseudo-first order rate constant was 0.223 ± 0.001 h −1 . It is proved that MCM-41-S-ImBr could be used at least 4 times without obvious decrease in catalytic performance. A possible reaction mechanism was also proposed: the quaternary imidazolium ion cooperatively worked with the bromide ion to catalyze the reaction. Graphical Abstract
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INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Zhixing Huang,Yujie ChenYang,Xiaohang Wang,Rui Cai,Benyong Han
In this study, twelve choline-based amino acid ionic liquids ([Cho][AA]-ILs) were synthesized employing amino acids and choline as raw materials. [Cho][AA]-ILs were effectively employed as catalysts in the biodiesel preparation via the transesterification of soybean oil with methanol. Among the synthesized [Cho][AA]-ILs, cholinium arginate ([Cho][Arg]) was selected as the appropriate catalyst. To optimize the primary experimental reaction conditions (methanol to oil molar ratio, catalyst load, reaction temperature, and reaction time), an experimental design was achieved by the A response surface methodology (RSM) based on the Box-Behnken design (BBD). The maximum biodiesel conversion of 98.58% was achieved with the [Cho][Arg] catalyst under the following optimal conditions: methanol to oil molar ratio of 9.13:1, catalyst load of 14.75%, a reaction time of 56.44 min and temperature 81.41 °C. A first-order kinetic of [Cho][Arg]-catalyzed transesterification of soybean oil with methanol was shown with activation energy and a pre-exponential factor of 10.06 kJ·mol −1 and 1.1707 min −1 , respectively. The ionic liquid [Cho][Arg] is a promising, easy to synthesize, and biodegradable catalyst that can replace traditional catalysts for the synthesis of biodiesel.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Haiyan Jiang,Tingting Li,Lu Bai,Jiuli Han,Xiaochun Zhang,Haifeng Dong,Shaojuan Zeng,Shuangjiang Luo,Xiangping Zhang
An efficient separation technology involving ammonia (NH3) and carbon dioxide (CO2) is of great importance for achieving low-carbon economy, environmental protection, and resource utilization. However, directly separating NH3 and CO2 for ammonia-based CO2 capture processes is still a great challenge. Herein, we propose a new strategy for selective separation of NH3 and CO2 by functional hybrid membranes that integrate polyimide (PI) and ionic liquids (ILs). The incorporated protic IL [Bim][NTf2] is confined in the interchain segment of PI, which decreases the fractional free volume and narrows the gas transport channel, benefiting the high separation selectivity of hybrid membranes. At the same time, the confined IL also provides high NH3 affinity for transport channels, promoting NH3 selective and fast transport owing to strong hydrogen bonding interaction between [Bim][NTf2] and NH3 molecules. Thus, the optimal hybrid membrane exhibits an ultrahigh NH3/CO2 ideal selectivity of up to 159 at 30 °C without sacrificing permeability, which is 60 times higher than that of the neat PI membrane and superior to the state-of-the art reported values. Moreover, the introduction of [Bim][NTf2] also reduces the permeation active energy of NH3 and reverses the hybrid membrane toward “NH3 affinity”, as understood by studying the effect of temperature. Also, NH3 molecules are much easier to transport at high temperature, showing great application potential in direct NH3/CO2 separation. Overall, this work provides a promising ultraselective membrane material for ammonia-based CO2 capture processes.
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PubMed
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 37
·e202301015
·
IF 2.1
Heming Zhang,Chan Meng,Qian Su,Li Dong,Wen Liu,Xiaokang Wang,Yunong Li,Weiguo Cheng
Graphical In this work, a series of halogen-free phosphonium ionic liquids (ILs) regulated by steric hindrance were designed and synthesized, for the catalytic synthesis of cyclic carbonates from CO 2 and epoxides, the effect of catalyst structures with different steric hindrance on catalytic activity was studied, and a plausible synergistic catalytic mechanism was proposed. The halogen-free bifunctional ILs proposed in this study provides a new insight on catalyst design and CO 2 utilization. In the cycloaddition reaction of carbon dioxide (CO 2 ) with epoxides, halogen catalysts lead to halogen loss and environmental pollution. It is necessary to design efficient and environmentally friendly catalysts. A series of halogen-free phosphonium ionic liquids (ILs) regulated by steric hindrance were designed and synthesized. It is further used as effective catalysts for the catalytic conversion of CO 2 into cyclic carbonates. The effect of different catalyst structures on catalytic activity has been investigated. Amino group has been shown to contribute to increased activity, and its location determines the degree of increased activity. Among them, [Bu 4 P] 2 [5-AMP] with meta-substitution showed the best catalytic activity, the conversion of propylene oxide (PO) was 96 % at the optimum conditions of 120 °C, 2 MPa and 3 h. Based on characterization analysis and DFT calculations, the interaction of ILs with CO 2 and PO were revealed. Finally, a plausible synergistic catalytic mechanism was proposed. The halogen-free, metal-free phosphonium ILs proposed in this paper provide a new insight on catalyst design and CO 2 utilization.
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SENSORS AND ACTUATORS B-CHEMICAL
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2021
·
IF 7.46
Wenyan Yin,Khaled Tawfik Alali,Milin Zhang,Jingyuan Liu,Dalei Song,Qi Liu,Jing Yu,Rongrong Chen,Hongsen Zhang,Jun Wang
Ionic liquids are widely employed as electrolytes for electrochemical oxygen sensing due to their excellent physical and chemical properties. Recently, combining inorganic electrochemically active materials with ionic liquids are becomes intensively interesting to improve oxygen sensor performance. In this paper, two imidazolyl-based ionic liquids 1-ethyl-2,3-dimethylimidazole bis((trifluoromethyl)sulfonyl)imide [Emmim][TFSI] and 1-butyl-2,3-dimethylimidazole bis((trifluoromethyl)sulfonyl)imide [Bmmim][TFSI] with three saturated alkyl substituents on the aromatic ring were prepared by a traditional two-step method. Under the electrochemical test, both ionic liquids exhibit a certain responsibility to different concentrations of oxygen. Subsequently, α-Fe 2 O 3 /rGO was prepared by hydrothermal method and then mixed with the ionic liquids to prepare a composite ionic liquid electrolyte for detecting a wide range of oxygen concentrations. The response performance of prepared composite electrolyte toward the oxygen is improved, which exhibits a sensitivity of 0.1041 μA/[%O 2 ] to gradually changed oxygen concentration and a linear correlation (R 2 ) of 0.9997 between oxygen reduction peak currents. Hence, the results show that the pure ionic liquid has a certain ability to detect oxygen, while adding α-Fe 2 O 3 /rGO compounds further improve responsibility, stability and sensitivity of composite electrolyte to oxygen.
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