scholarly journals Transformations of xylenes in trimethylammonium hydrochloride—Aluminum chloride ionic liquid

2003 ◽  
Vol 1 (3) ◽  
pp. 305-313
Author(s):  
V. Ksenofontov ◽  
L. Kustov

AbstractIsomerization of m-, o-and p-xylenes in the presence of trimethylammonium hydrochloride-AlCl3 ionic liquid with different composition was studied. Ionic liquids with the following ammonium salt: AlCl3 molar ratios were used: 1∶2, 1∶1.5 and 1∶1.25. It was shown that isomerization of xylenes proceeds under mild conditions at temperatures from 60°C to 110°C. It was found that the activity and selectivity of the ionic liquids depends on their composition. The most effective catalyst was the ionic liquid with the ammonium salt: AlCl3 molar ratio equal to 1∶2.

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hang Xu ◽  
Tianlong Yu ◽  
Mei Li

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.


2011 ◽  
Vol 197-198 ◽  
pp. 906-910
Author(s):  
Hui Ru Liu ◽  
Li Qiang Lv ◽  
Xing Chen Zhang

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.


2019 ◽  
Vol 21 (3) ◽  
pp. 567-577 ◽  
Author(s):  
Wenfeng Zhao ◽  
Xiaoping Chi ◽  
Hu Li ◽  
Jian He ◽  
Jingxuan Long ◽  
...  

A sustainable and recyclable ionic liquid catalytic system is developed to be efficient in N-methylation or N-formylation of amines with CO2 under mild conditions.


2014 ◽  
Vol 989-994 ◽  
pp. 676-679 ◽  
Author(s):  
Xue Lan Zhang ◽  
Deng Feng Wang

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.


2012 ◽  
Vol 476-478 ◽  
pp. 2621-2624
Author(s):  
Xue Lan Zhang ◽  
Deng Feng Wang

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.


2005 ◽  
Vol 2005 (9) ◽  
pp. 613-616 ◽  
Author(s):  
Weixing Qian ◽  
Erlei Jin ◽  
Weiliang Bao ◽  
Yongmin Zhang

Several 2,4-dialkyl-3,5-bis(arylimino)-1,2,4-thiadiazolidines were synthesised under mild conditions in good yield by the selective oxidation of N-alkyl-N'-arylthioureas by using 1-(4-diacetoxyiodobenzyl)-3-methyl imidazolium tetrafluoroborate [dibmim]+[BF4]- in ionic liquids.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yasir Ali Elsheikh ◽  
Faheem Hassan Akhtar

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.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1089
Author(s):  
Ana P. C. Ribeiro ◽  
Peter Goodrich ◽  
Luísa M. D. R. S. Martins

The production of cyclic carbonates from CO2 cycloaddition to epoxides, using the C-scorpionate iron(II) complex [FeCl2{κ3-HC(pz)3}] (pz = 1H-pyrazol-1-yl) as a catalyst, is achieved in excellent yields (up to 98%) in a tailor-made ionic liquid (IL) medium under mild conditions (80 °C; 1–8 bar). A favorable synergistic catalytic effect was found in the [FeCl2{κ3-HC(pz)3}]/IL system. Notably, in addition to exhibiting remarkable activity, the catalyst is stable during ten consecutive cycles, the first decrease (11%) on the cyclic carbonate yield being observed during the 11th cycle. The use of C-scorpionate complexes in ionic liquids to afford cyclic carbonates is presented herein for the first time.


2021 ◽  
Vol 18 ◽  
Author(s):  
Sakthinarayanan Jayaraman ◽  
Uthayanila Selvarasu ◽  
Ganesh Gopalsamy Selvaraj ◽  
Karthikeyan Parasuraman

: Bifunctional ionic liquid [BIL] was found to be a highly effective catalyst for the ether synthesis without any inorganic base or solvent. By this protocol, different aryl substitutions were reacted with different phenol in good to excellent yields. The BIL is reusable without any loss in catalytic activity for nine consecutive cycles. Background: The Williamson reaction is a convenient renovation in fine chemical synthesis since the ethers are important in both bulk and fine industrial chemicals preparation and academic applications. Objective: The aim of this study is to highlight the use of BIL to synthesize mixed ethers using substituted phenols and to study the reusability in the next cycle. Method: The mixture of the phenol (1mmol), alcohol (1.2 mmol) and BIL ionic liquid (0.3 mol%) was added in to round-bottomed flask (100 mL) with continuous stirring for 1 hour. Results: The products obtained were phenol and substituted phenols containing withdrawing substituents in respectable yields. However, the reactions involving substituted phenols containing electron-donating groups often afford the corresponding products in low yields. Conclusion: BIL is found to be an effective catalyst in the etherification of various unsymmetrical ethers under mild conditions. Bifunctional ionic liquid as a solvent and catalyst will show real rewards by providing a ‘green’ method with the safer procedure, less reaction time periods, mild conditions, separation easy, and ionic liquid recycle.


2008 ◽  
Vol 63 (1-2) ◽  
pp. 66-72 ◽  
Author(s):  
Olga B Babushkina

A series of ionic liquids consisting of 1-butyl-1-methylpyrrolidinium chloride (Pyr14Cl) and TaCl5 at molar ratios of Pyr14Cl in the range of 0.85 - 0.20 was synthesized. They exhibit potential application as electrolytes for the electrochemical deposition of tantalum. The thermal behaviour of the Pyr14Cl-TaCl5 mixtures was investigated, using differential scanning calorimetry (DSC) to estimate the range of thermal stability and to determine the optimal compositions for electrochemical trials. The Pyr14Cl-TaCl5 mixtures formed stoichiometric 3 : 2 and 2 : 3 crystalline phases with melting points of 70 °C and 130 °C, respectively, characterized by entropies of fusion of 13.6 JK−1 mol−1 and 10.1 JK−1 mol−1. The mixtures with molar fractions of Pyr14Cl equal to 0.60 and 0.40 were clear and transparent liquids and had the lowest viscosity; they were the most suitable for electrochemical applications. FTIR spectra of the Pyr14Cl-TaCl5 mixtures allowed to get insight into inter-ionic interactions and the nature of formation of these ionic liquids as a function of the molar ratio of the components.


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