scholarly journals Zinc Acetate Immobilized on Mesoporous Materials by Acetate Ionic Liquids as Catalysts for Vinyl Acetate Synthesis

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hang Xu ◽  
Tianlong Yu ◽  
Mei Li
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Vinyl Acetate ◽  
Silica Gel ◽  
Catalyst Activity ◽  
Catalyst Layer ◽  
Space Velocity ◽  
Molar Ratio ◽  
Vinyl Acetate Monomer ◽  
Adsorption Desorption

Ionic liquid containing active ingredient Zn(CH3COO)2was loaded in mesoporous silica gel to form supported ionic liquids catalyst (SILC) which was used to synthesize vinyl acetate monomer (VAM). SILC was characterized by1HNMR, FT-IR, TGA, BET, and N2adsorption/desorption and the acetylene method was used to evaluate SILC catalytic activity and stability in fixed reactor. The result shows that 1-allyl-3-acetic ether imidazole acetate ionic liquid is successfully fixed within mesoporous channel of silica gel. The average thickness of ionic liquid catalyst layer is about 1.05 nm. When the catalytic temperature is 195°C, the acetic acid (HAc) conversion is 10.9% with 1.1 g vinyl acetate yield and 98% vinyl acetate (VAc) selectivity. The HAc conversion is increased by rise of catalytic temperature and molar ratio of C2H2 : HAc and decreased by mass space velocity (WHSV). The catalyst activity is not significantly reduced within 7 days and VAc selectivity has a slight decrease.

Ionic Liquid [Bmim]OH Grafted Catalyst for Cycloaddition of Carbon Dioxide

2014 ◽  
Vol 989-994 ◽  
pp. 676-679 ◽  
Author(s):  
Xue Lan Zhang ◽  
Deng Feng Wang
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Silica Gel ◽  
Propylene Carbonate ◽  
Propylene Oxide ◽  
Heterogeneous Catalysts ◽  
Element Analysis ◽  
Mild Conditions ◽  
Adsorption Desorption

An ionic liquid 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) was grafted on silica gel by post-grafting method. Such grafted ionic liquids (GILs) which were verified by means of FTIR, element analysis N2adsorption-desorption and TG could be used as highly effective heterogeneous catalysts toward propylene carbonate synthesis through cycloaddition of carbon dioxide with propylene oxide under solventless and mild conditions.

Preparation and Activity of Ionic Liquid Catalysts Grafted on Hydrophobic Silica Gel

2012 ◽  
Vol 476-478 ◽  
pp. 2621-2624
Author(s):  
Xue Lan Zhang ◽  
Deng Feng Wang
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Silica Gel ◽  
Propylene Oxide ◽  
Heterogeneous Catalysts ◽  
N2 Adsorption ◽  
Mild Conditions ◽  
Hydrophobic Silica ◽  
Adsorption Desorption

An ionic liquid 1- (triethoxysilyl) propyl-3-methylimidazolium hydroxide ([Smim]OH) was grafted on three kinds of mesoporous hydrophobic silica gel by means of post-grafting under mild conditions. The catalysts were [Smim]OH/SiO2-MTES (methyltriethoxysilane), [Smim]OH/SiO2-TMCS (trimethylchlorosilane), [Smim]OH/SiO2-CPTEO (triethoxysilyl propyl chloride). Such grafted ionic liquids (GILs), which were characterized by means of FTIR and N2 adsorption-desorption could be used as effective heterogeneous catalysts toward propylene carbonate synthesis through cycloaddition of carbon dioxide with propylene oxide under solventless and mild conditions.

Synthesis and Characterization of Super-Molecular Ionic Liquids

2011 ◽  
Vol 197-198 ◽  
pp. 906-910
Author(s):  
Hui Ru Liu ◽  
Li Qiang Lv ◽  
Xing Chen Zhang
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Melting Point ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
Raw Materials ◽  
Ammonium Thiocyanate ◽  
Molar Ratio ◽  
Molecular Ion

This study concerned a novel super-molecular ionic liquid synthesized by ammonium thiocyanate and caprolactam. The physical characters such as melting point and electric conductivity were investigated. Results showed that the melting point is -12.2°C at the molar ratio of 3:1 (caprolactam/ammonium thiocyanate), which is much lower than raw materials. The electric conductivities of synthesized ionic liquids were close to that of imidazole ILs. The structure of ionic liquid was characterized by IR,1HNMR and quantum chemical calculations. It was shown that the NH4+cation connected with caprolactam organic molecules by hydrogen bonds, leading to the forming of a super-molecular ion. The electrostatic attraction of super-molecular ion with anion was decreased because of the larger volume of super-molecular ion than original cation, thus the melting point decreased. The key properties that distinguish super-molecular ionic liquid from other ILs were the presence of supermolecular ion, which can be used to build up a hydrogen-bonded network. This type ion liquid was named as super-molecular ion liquid.

Ionophilic phosphonium-appended carbopalladacycle catalyst for Suzuki–Miyaura and Heck cross-coupling catalysis

2010 ◽  
Vol 88 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Jocelyn J. Tindale ◽  
Paul J. Ragogna
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Catalyst Activity ◽  
Reaction Medium ◽  
Cross Coupling ◽  
Metal Catalyst ◽  
Phosphonium Salts ◽  
Transition Metal Catalyst ◽  
Imidazolium Ionic Liquids ◽  
Liquid Reaction

An ionic liquid, covalently tethered to an efficient transition-metal catalyst in the presence of an ionic liquid reaction medium, can utilize ionophilic interactions to improve catalyst activity, recyclability, and product isolation while decreasing catalyst leaching. Given the greater stability of phosphonium salts in comparison to imidazolium ionic liquids under basic conditions, phosphonium-tagged oxime carbopalladacycle salts were prepared and employed in both Heck and Suzuki–Miyaura reactions. The desired product was obtained in good yields for up to four catalyst cycles in the case of the Suzuki–Miyaura reaction. While taking advantage of the non-volatile nature of ionic liquids, the product was isolated through simple sublimation from the reaction mixture, eliminating issues associated with catalyst leaching, and the remaining ionic liquid solvent–catalyst mixture was ready for further catalysis.

scholarly journals Biodiesel fromCitrullus colocynthisOil: Sulfonic-Ionic Liquid-Catalyzed Esterification of a Two-Step Process

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yasir Ali Elsheikh ◽  
Faheem Hassan Akhtar
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Sulfonic Acid ◽  
Molar Ratio ◽  
Disulfonic Acid ◽  
Hydrogen Sulfate ◽  
Citrullus Colocynthis ◽  
Step Process ◽  
Acidic Catalyst ◽  
Acidic Catalysts

Biodiesel was prepared fromCitrullus colocynthisoil (CCO) via a two-step process. The first esterification step was explored in two ionic liquids (ILs) with 1,3-disulfonic acid imidazolium hydrogen sulfate (DSIMHSO4) and 3-methyl-1-sulfonic acid imidazolium hydrogen sulfate (MSIMHSO4). Both ILs appeared to be good candidates to replace hazardous acidic catalyst due to their exceptional properties. However, the two sulfonic chains existing in DSIMHSO4were found to increase the acidity to the IL than the single sulfonic chain in MSIMHSO4. Based on the results, 3.6 wt% of DSIMHSO4, methanol/CCO molar ratio of 12 : 1, and 150°C offered a final FFA conversion of 95.4% within 105 min. A 98.2% was produced via second KOH-catalyzed step in 1.0%, 6 : 1 molar ratio, 600 rpm, and 60°C for 50 min. This new two-step catalyzed process could solve the corrosion and environmental problems associated with the current acidic catalysts.

The Soft Measurement of Catalyst Activity in VAc Synthesis

2014 ◽  
Vol 602-605 ◽  
pp. 2000-2003
Author(s):  
Hua Meng ◽  
Long Liu ◽  
Yue Ying Wang
Keyword(s):  
Support Vector Machine ◽  
Zinc Acetate ◽  
Catalyst Activity ◽  
Space Velocity ◽  
Molar Ratio ◽  
Main Trend ◽  
Support Vector ◽  
Soft Measurement ◽  
Change Trend ◽  
Main Change

Zinc acetate serves as the catalyst in the synthesis reaction of VAc, the activity of zinc acetate will lose with the changes of the using time, temperature, space velocity, molar ratio. For the realization of soft measurement of the catalyst activity, the mathematical regression method and support vector machine (SVM) method are combined to model. By adopting the method of mathematical regression, the main change trend of catalyst activity can be illuminated with the change of response time; The support vector machine (SVM) method is used to amend the main trend to truly achieve the accurate and reliable soft measurement of catalyst activity[1]。The simulation is proceed by the MATLAB to compare to the field datas, the simulation results show that the model established by the mixed modeling approach is high-precision and reliable. The requirements of the soft measurement for catalyst activity in VAc synthesis can be satisfied.

Platinum nanoparticles supported on ionic liquid-modified-silica gel: hydrogenation catalysts

RSC Advances ◽  
2014 ◽  
Vol 4 (32) ◽  
pp. 16583-16588 ◽  
Author(s):  
Lucas Foppa ◽  
Jairton Dupont ◽  
Carla W. Scheeren
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Silica Gel ◽  
Platinum Nanoparticles ◽  
Sol Gel ◽  
Modified Silica ◽  
Silica Network ◽  
Modified Silica Gel ◽  
Hydrogenation Catalysts ◽  
Gel Method

Platinum nanoparticles (ca. 2.3 nm) dispersed in ionic liquids and functionalized ionic liquids were supported within a silica network by the sol–gel method.

scholarly journals Recycling of 1,2-Dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide Ionic Liquid by Stacked Cation and Anion Exchange Adsorption-Desorption

Separations ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Cynthia A. Corley ◽  
Scott T. Iacono
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ion Exchange ◽  
Anion Exchange ◽  
Membrane Separation ◽  
Ion Pairs ◽  
Exchange Adsorption ◽  
Adsorption Desorption ◽  
Desorption Method

There are many advantages to using ionic liquids as solvents or catalysts in chemical processes. Their non-volatile characteristic and high cost, however, can pose economic, environmental, and long-term health concerns. As such, the recovery and recycling of ionic liquids have become essential to mitigate their environmental impact and to reduce costs. Numerous recovery and recycling methods have been reported, including distillation, extraction, membrane separation (a.k.a. filtration), adsorption, crystallization, gravity, and electrochemical separation. Whereas most of these methods recover both cations and anions of the ionic liquid as ion pairs, recycling methods such as single-phase ion exchange or mixed-ion exchange/non-ionic adsorption methods recover only one of the ionic liquid ions, typically the cation. These methods are frequently used for the recycling of ionic liquids having simple anions such as chloride or acetate, but are seldom employed for ionic liquids consisting of larger and more complex anions due to the added time and reagent costs necessary for the regeneration of the original ionic liquid. Herein, a combined cation and anion exchange adsorption-desorption method is presented that can effectively separate 1,2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonimide) [DMPIm][NTf2] ionic liquid from neutral impurities. More importantly, the method is capable of recovery and recycling of the original ionic liquid. Concomitant desorption of both ionic liquid ions was achieved using 0.1 M NaCl: methanol (90:10 v/v) eluent followed by isolation using liquid–liquid extraction to afford high purity products and yields of approximately 60%.

Catalytic Combustion of Vinyl Chloride Emission over a TiO2–MnOx Catalyst

2017 ◽  
Vol 42 (3) ◽  
pp. 259-268 ◽  
Author(s):  
Yiling Wan ◽  
Xiangyu Xie ◽  
Xiaojun Chen
Keyword(s):  
Vinyl Chloride ◽  
Catalytic Combustion ◽  
Active Oxygen Species ◽  
Catalyst Activity ◽  
Sol Gel ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
Preparation Conditions ◽  
Diffraction Peaks

TiO2–MnO x catalyst samples with different Ti/(Ti + Mn) molar ratios (2:3, 3:4, 4:5, 5:6, 6:7 and 1) prepared by the citric acid (CA) sol-gel method were studied in the catalytic combustion of vinyl chloride (VC) emission. The effects of preparation conditions and operation parameters on the catalytic performance of TiO2–MnO x were investigated. The catalyst samples were characterised by N2 adsorption, X-ray diffraction (XRD) and H2-temperature programmed reduction (H2-TPR). In the catalytic combustion of VC over TiO2–MnO x, products containing HCl, CO2, and H2O were obtained and there were no by-products such as chlorohydrocarbons and chlorine. The TiO2–MnO x catalyst with the molar ratio of CA/Mn/Ti = 0.30:0.20:0.80 showed the best catalytic performance and had better operating flexibility over the ranges of gas hourly space velocity (GHSV) of 15000–100000 h−1 and VC concentration of 0.05–2.00%. The temperatures at 50% conversion (140 °C) and at 99% conversion (220 °C) were achieved at a VC concentration of 0.1% and GHSV of 15000 h−1. XRD characterisation indicated that only the characteristic diffraction peaks of TiO2 with the anatase structure appeared and no characteristic diffraction peaks of MnO x species appeared for the TiO2–MnO x catalyst. XRD and H2-TPR results indicated that Mn ions were incorporated into the TiO2 lattice to form a Ti–Mn–O solid solution, which enhanced the reactivity of active oxygen species on the catalyst surface and thereby promoted the catalyst activity.

Immobilization of Acidic Ionic Liquid on Silica Gel for Catalytic Oxidative Desulfurization of Fuel Oils(II): Desulfurization

2015 ◽  
Vol 1090 ◽  
pp. 183-187 ◽  
Author(s):  
Kai Peng Cheng ◽  
Hao Yang ◽  
Jian Hong Wang ◽  
Hui Peng Liu ◽  
Cong Zhen Qiao
Keyword(s):  
Ionic Liquid ◽  
Reaction Time ◽  
Silica Gel ◽  
Oxidative Desulfurization ◽  
Molar Ratio ◽  
Acidic Ionic Liquid ◽  
Fuel Oils ◽  
Catalytic Oxidative Desulfurization ◽  
Highly Dispersed ◽  
Model Oil

A series of highly dispersed ionic liquid catalysts were used for the oxidation desulfurization of dibenzothiophene (DBT) in model oil in the presence of H2O2. The effects of the loading of [BMIM]HSO4immobilized, reaction time, temperature, O/S molar ratio and the dosage of catalysts on DBT removal were investigated in detail. The catalyst with the loading of [BMIM]HSO4was 25% exhibited the highest activity. The DBT removal of model oil can reach 99.9% in 5 h at 60 °C, O/S molar ratio of 10, Vmodeloil=10mL, mcatalysts=2.00g. The catalysts can be easily recycled and can be recycled 2 times without a significant decrease in activity.

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