Catalysts
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2023
·Vol. 13
·期 3
·640
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IF 3.9
Cong Wang,Gang Li,Hongchen Guo
MOFs have attracted widespread attention in the field of catalytic ethylene dimerization. Compared with post-synthetic modification, ion exchange and other methods to introduce external active centers, the direct use of MOF materials as catalysts is still the most convenient and prospective. Herein, the NiBTCs are synthesized using a one-pot method in two kinds of solvent and characterized by XRD, FT–IR, ICP–OES, XPS, TGA and N2physical adsorption. After treatment at 150 °C, the catalytic activities of both materials in ethylene dimerization are up to 470.9, and 647.0 gpro./(gcat.·h) and the selectivity of 1-butene in all products could reach 83.2% and 81.7%, respectively. Stability testing of the catalysts demonstrated that they do not decompose during the reaction, but their reuse performance is degraded. In addition, a probable Cossee–Arlman–type mechanism is proposed. The NiBTCs are shown to have superior catalytic performance in ethylene dimerization compared to employing Ni(pyz)2Cl2or α–Ni(im)2as catalysts.Keywords:ethylene dimerization;NiBTCs;MOFs;1-butene
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Fei Gao,Cailin Ji,Shougui Wang,Jipeng Dong,Changqing Guo,Yuwen Gao,Guanghui Chen
Integrating multifunctional active sites into an appropriate porous material is a promising strategy to achieve great catalytic performance for CO 2 cycloaddition . Herein, carboxy-functionalized imidazolium ionic liquid were successfully anchored onto the MCM-41 mesoporous silicates. The resultant MCM-41-Imi/COOH integrates hydrogen bond donor, Lewis base and nucleophilic ionic sites, and possesses a high surface area and mesopore structure. As-prepared catalyst achieves a good catalytic activity for CO 2 cycloaddition with propylene oxide under cocatalyst- and solvent-free conditions. Moreover, the catalyst MCM-41-Imi/COOH exhibits the good cycling stability and versatility to various epoxides . In particular, the catalyst shows a satisfactory catalytic activity for catalyzing dilute CO 2 conversion to cyclic carbonate. Furthermore, a possible reaction mechanism for the cycloaddition of CO 2 with propylene oxide over the catalyst MCM-41-Imi/COOH was proposed.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Jing Chen,Jiakun Yang,Qin Wu,Daxin Shi,Kangcheng Chen,Yaoyuan Zhang,Xiaoyan Zheng,Hansheng Li
The cycloaddition reaction of CO 2 with epoxides is challenging, thereby requiring the development of environmentally friendly catalysts. Herein, a strategy was developed to construct a multifunctional heterogeneous magnetic catalyst (MPNPs-[ImR 2 NH 2 ][ZnBr 3 ]) of aminoethyl imidazole metal halide ionic liquids coated on nano-sized CoFe 2 O 4 @polystyrene for CO 2 cycloaddition. The created catalytic system displayed the intramolecular synergy of ternary active sites (Zn 2+ , Br − , and –NH 2 ), as well as coupling of catalysis and magnetic separation. In the absence of co-catalyst and solvent, MPNPs-[ImR 2 NH 2 ][ZnBr 3 ] exhibited excellent catalytic performance for CO 2 cycloaddition (99.92% yield and 100% selectivity) at 120 ℃ with 0.16 mol% catalyst dosage in 2.5 h. By appropriately increasing the reaction duration and catalyst dosage, 98.83% conversion and 99.26% selectivity were achieved even at mild conditions of 60 °C and 0.1 MPa. After 10 cycles of reuse, the recycled MPNPs-[ImR 2 NH 2 ][ZnBr 3 ] demonstrated the same high-efficiency activity as the fresh catalyst, as well as excellent stability and magnetic separation. Based on the density functional theory (DFT) calculations, the intramolecular synergy of ternary active sites and the catalytic mechanism of bimolecular activation based on the multifunctional structure were proposed. This excellent catalyst was attributed to the intramolecular synergy of ternary active sites, large loading of active centers, lower internal diffusion resistance, the inert protective effect of polystyrene layer and the easily magnetic separation of CoFe 2 O 4 , highlighting a new direction for green catalytic chemistry.
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RSC Advances
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2023
·Vol. 13
·期 14
·9347-9352
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IF 3.9
Yu-Fen Bao,Yi-Jie Wang,Yu-Chen Wang,Ding-Hua Liu
In the synthesis of dimethyl carbonate (DMC) by transesterification, CH3ONa has been commonly applied as a homogeneous catalyst due to its high catalytic activity, but its stability is unsatisfactory. Here, by studying the influence of ionic liquid base strength on transesterification, we prepared an organic base catalyst, potassium imidazole (KIm), with high catalytic activity and stability, which solved the problem of catalyst deactivation in transesterification. The results showed that when KIm was used in the synthesis of DMC from propylene carbonate (PC) and methanol (MeOH), the chemical equilibrium could be reached within 3 minutes and the yield of DMC reached 73.03%, indicating that KIm performed better in transesterification than the majority of previously reported catalysts. In addition, the activity of the catalyst had hardly decreased after ten cycles of reaction, which can well meet the requirements of industrial production.
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CATALYSIS TODAY
·
2023
·
IF 5.3
Wensheng Wei,Yuxin Wang,Zizhen Yan,Jiaxiang Hou,Guangwen Xu,Lei Shi
Three quaternary ammonium ionic liquids with strong nucleophilicity and distinctive structures were synthesized with high yield and purity based on the 1,2-propylene glycol anion (CH 3 CH 2 OHCH 2 O - ) derived from transesterification products. Dimethyl carbonate (DMC) was in turn produced via a one-step reaction among propylene oxide (PO), CO 2 , and methanol (MeOH) by using the synthesized ionic liquids. The involved two-stage catalytic reaction of PO-CO 2 cycloaddition and PC-MeOH transesterification was implemented without catalyst separation. Under mild conditions, the PO conversion reached 99.0%, with a PC yield of 99.0%, and a TON value of 119.5. Following the cycloaddition, MeOH was immediately introduced to achieve a PC conversion of 71.2%, a selectivity to DMC above 99%, and a TON value of 57.4 for the transesterification reaction. The influences of temperature as well as time for cycloaddition and transesterification were investigated. Cycloaddition of CO 2 with various epoxides was also examined and all showed good performance. By taking advantage of the decomposability of as-prepared ionic liquids and the recyclability of decomposition products, a new catalyst circulation process was designed to complete the full cycle without introduction of any impurities into the product system.
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POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Jingsheng Wang,Xi Chen,Jun Wang,Shuang Yang,Kaiwen Chen,Lu Zhu,Siqi Huo,Pingan Song,Hao Wang
Carbon fiber reinforced polymer (CFRP) composite is a kind of lightweight material with excellent comprehensive properties, but low production efficiency and inherent flammability have become two crucial limitations for its further application. Herein, two phosphorus-derived imidazoliums (CEPM-1 and CEPM-2) were synthesized by aqueous self-assembly, and applied to flame-retardant, one-component epoxy resins (EPs). Moreover, the well-designed EPs (EP/CEPM-1–25 and EP/CEPM-2–20) were used as resin matrixes for CFRP. Both EPs featured superior latency and modest-temperature fast curing, especially EP/CEPM-1-25, which had a long shelf life of 30 days and can gel within 20 min at 150 °C. The limiting oxygen index (LOI) and UL-94 classification of EP/CEPM-1-25 were 33.0% and V-0, indicative of superior flame retardancy. The total smoke production and maximum smoke density of EP/CEPM-1-25 displayed 37.7 and 72.1% reductions relative to those of the control EP sample cured by imidazole, demonstrating improved smoke suppression. EP/CEPM-2-20 also displayed satisfactory fire safety, but slightly inferior to EP/CEPM-1-25. As expected, the CFRP composites based on EP/CEPM-1-25 and EP/CEPM-2-20 showed high LOIs (42.5 and 39.0%) and UL-94 V-0 classification due to the inhibition of P-containing groups in CEPM-1 and CEPM-2 on the wick effect. Therefore, this work proposes a facile and ‘green’ methodology to create high-performance, intrinsically fire-safe single-component EPs and CFRP composites.
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JOURNAL OF MOLECULAR LIQUIDS
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2023
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IF 6
Lihua Zhou,Xiangbin Fan,Yang He,Shaohua Gou,Qiankun Bi,Junwen Chen,Lei Chen,Jun wang,Hua Guo,Yuanpeng Wu,Hairong Yue,Xingfu Li
The long-term effect of protecting water-sensitive reservoirs and enhancing permeability of water invasion reservoir is still an urgent practical problem to be solved. Here, an imidazolium Gemini ionic liquid (IL), PEG-DC 8 Im, with octyl as tail chain and polyoxyethylene chain as bridging group, was synthesized to inhibit the hydration, swelling and dispersion of clay minerals. The PEG-DC 8 Im could exert excellent anti-swelling ability (93.82 %) and outstanding washable capacity (cumulative decrease of anti-swelling rate after being washed five times: 1.32 %) at the concentration of 60 mmol/L. The inhibition effect of 20 mmol/L PEG-DC 8 Im was significantly better than that of 250 mmol/L KCl at 90 °C. And the PEG-DC 8 Im could intercalate into the interlayer space of MMT through cation exchange to play an inhibition effect, where zeta potential of MMT particles was reduced and then the dispersion ability of MMT was weakened. Subsequently, the anionic polymer poly(AM/AA) was found to cooperate with PEG-DC 8 Im to improve the inhibition effect for MMT swelling and dispersion, in which poly(AM/AA) was not intercalated into the interlayer of MMT, and only adsorbed on the surface of the particles to encapsulate the MMT particles. Simultaneously, the apparent viscosity and thixotropy of the composite solution were enhanced. Besides, after the treatment of PEG-DC 8 Im, the displacement pressure decreased and the permeability of sandstone cores increased due to the inhibition of clay mineral hydration, revealing the enhancement of injectivity. Finally, the pore connectivity of the core increased and the water wettability was weakened. The treatment of PEG-DC 8 Im was conducive to the discharge of invasive water in reservoir and the improvement of the reservoir permeability. Overall, PEG-DC 8 Im has a good application prospect as permeability-enhancing clay stabilizers.
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BIORESOURCE TECHNOLOGY
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2022
·
IF 11.889
Cong-Jia Duan,Xu Han,Yuan-Hang Chang,Jian Xu,Gan-Lu Yue,Ying Zhang,Yu-Jie Fu
A novel ternary deep eutectic solvent (DES), consisted of choline chloride, oxalic acid and ethylene glycol, was developed as a green, low-cost and recyclable pretreatment system for multi-stage utilization of Eucommia ulmoides seed shells. Under optimum conditions, 79.7 % hemicellulose and 65.6 % lignin were quickly removed while 84.0 % cellulose was retained. After DES pretreatment , the yield and purity of gutta-percha achieved 85.1 mg/g and 96.2 %, which increased 1.4 and 1.8 folds higher than that of un-treatment ones. Meanwhile, 69.1 % enzymatic digestibility of cellulose was obtained, that was 2.3 folds higher than that of raw substrates. Moreover, 53.6 % low-condensation lignin with aromatic structures and valuable aryl-ether linkages was well collected. Importantly, the DES that has been recycled five runs can still remove 73.9 % hemicellulose and 58.0 % lignin. Overall, the DES was determined to efficiently promote the separation and conversion of high-quality gutta-percha, value-added lignin and high-yield glucose from Eucommia ulmoides seed shells.
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JOURNAL OF CHROMATOGRAPHY A
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2022
·
IF 4.601
Lizhen Qiao,Yuan Tao,Honglin Qin,Ruiting Niu
In this paper, several new multi-magnetic center magnetic ionic liquids (MMILs) were prepared with paramagnetic component simultaneously contained in both the cation and anion and used as extractants to establish a dispersive liquid-liquid microextraction (DLLME) approach followed by in-situ MMIL decomposition based back-extraction for the enrichment and determination of four parabens in beverages. The appropriate MMIL was selected by investigating the extraction performances of the obtained MMILs combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV), and some other experimental factors were explored. Under the optimized DLLME conditions, the four parabens exhibited coefficients of determination (R 2 ) above 0.9987 in the linear range of 0.1-500 ng·mL −1 for ethylparaben, propylparaben and butylparaben and 0.2-500 ng·mL −1 for methylparaben. The limits of detection (LODs) and limits of quantification (LOQs) were respectively within 0.03-0.06 ng·mL −1 and 0.1-0.2 ng·mL −1 , and the relative standard deviations (RSDs) for intra-day and inter-day precision were below 10.8%. Moreover, the application of the developed MMIL-based DLLME method in beverage samples exhibited recoveries within 81.3%-112.1% with RSDs of 0.3%-13.1% at three different spiked levels.
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JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Guowei Wang,Xiaoqing Xu,Yu Sun,Linghua Zhuang,Cheng Yao
Three ester-containing gemini imidazolium surface active ionic liquids [1,4-bis(1-alkyl-oxypropyl-imidazolium)-butane dichloride], abbreviated as [peC n Bim 2 ]Cl 2 ( n = 12, 14, 16), were synthesized from imidazole , 1,4-dibromobutane, 1-chloro-3-propanol, and various aliphatic carboxylic acids. Chemical structures of [peC n Bim 2 ]Cl 2 were confirmed by H-Nuclear magnetic resonance, Fourier transform infrared spectroscopy , and elemental analysis . Thermal properties of [peC n Bim 2 ]Cl 2 were studied with Thermogravimetric analysis and Differential scanning calorimetry . The micellization parameters, adsorption/aggregation properties, and thermodynamic parameters of [peC n Bim 2 ]Cl 2 were demonstrated using tensiometry, electrical conductivity. Critical micelle concentration values of [peC n Bim 2 ]Cl 2 aqueous solutions decreased with increasing the alkyl chain length (from C12 to C16). The formation of micelles was spontaneous, exothermic, and entropy-driven. Using OECD 301D, the aerobic biodegradation of nine gemini imidazolium SAILs ([peC n Bim 2 ]Cl 2 , [C n Pim 2 ]Br 2 , and [C n Bim 2 ]Br 2 ) and three monoimidazolium SAILs ([C n IM]Br) were systematically investigated to determine the relationship between biodegradation and structural elements of imidazolium SAILs. Aerobic biodegradation of twelve SAILs followed the decreasing trend: [peC n Bim 2 ]Cl 2 > [C n Pim 2 ]Br 2 > [C n IM]Br > [C n Bim 2 ]Br 2 . Gemini imidazolium SAILs with ester functional group ([C n Pim 2 ]Br 2 and [peC n Bim 2 ]Cl 2 ) showed much higher biodegradation rates than those of [C n IM]Br and [C n Bim 2 ]Br 2 . The location of ester group played an obvious role on biodegradation. Gemini SAILs containing ester group in the side alkyl chains ([peC n Bim 2 ]Cl 2 ) showed much higher biodegradation ratio than those of [C n Pim 2 ]Br 2 (ester functional group in spacer). [peC n Bim 2 ]Cl 2 could be classified as readily biodegradable. The biodegradability of gemini imidazolium SAILs increased with increasing the alkyl chain length.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Junhai Wu,Bihong Lv,Xiaomin Wu,Zuoming Zhou,Guohua Jing
A series of novel dual-functionalized ionic liquids (FILs) with the combinations of diethylenetriamine cation ([DETAH]+) and aprotic heterocyclic anion (AHA) are explored for efficient and reversible CO2 capture, which was distinguished from the traditional strategy by increasing the amino group number of ionic liquids. The structural features and the interactions between ions and CO2 were performed under the DFT method, at the B3LYP/6-311++G** level. The CO2 absorption loadings of [DETAH][Im], [DETAH][Py], and [DETAH][Tz] were 11.91, 11.36, and 10.10 mol CO2/ kg IL, respectively. After the fifth cycle, their regeneration efficiencies still kept above 90%. Based on the calculation and 13C NMR results, the reaction mechanisms of CO2 capture into [DETAH][AHA] solutions were clarified. The amino groups of [DETAH]+ reacted with CO2 to produce [DETAH]+-carbamates, which guaranteed the high absorption rate. Meanwhile, [AHA]− could also equimolecularly react with CO2 to form carbamate, which subsequently hydrolyzes into HCO3–/CO32–. Notably, the [AHA]− was protonated during the CO2 absorption process, and [AHA]-H could react with [DETAH]+-carbamates to produce [DETAH]+, which helped to recycle the active components of the absorbent and further increased the CO2 capacity and regenerability of the absorbent. The novel dual FILs present as an efficient candidate for CO2 capture.
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MOLECULES
·
2018
·Vol. 23
·期 11
·3033
·
IF 3.098
Shumei Xia,Yu Song,Xuedong Li,Hongru Li,Liang-Nian He
To circumvent the thermodynamic limitation of the synthesis of oxazolidinones starting from 2-aminoethanols and CO2and realize incorporation CO2under atmospheric pressure, a protic ionic liquid-facilitated three-component reaction of propargyl alcohols, CO2and 2-aminoethanols was developed to produce 2-oxazolidinones along with equal amount of α-hydroxyl ketones. The ionic liquid structure, reaction temperature and reaction time were in detail investigated. And 15 mol% 1,5,7-triazabicylo[4.4.0]dec-5-ene ([TBDH][TFE]) trifluoroethanol was found to be able to synergistically activate the substrate and CO2, thus catalyzing this cascade reaction under atmospheric CO2pressure. By employing this task-specific ionic liquid as sustainable catalyst, 2-aminoethanols with different substituents were successfully transformed to 2-oxazolidinones with moderate to excellent yield after 12 h at 80 °C.Keywords:ionic liquid;synergistic activation;aminoethanol;2-oxazolidinone;atmospheric CO2;sustainable catalysis
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危险品化学品经营许可证（带存储）