Search results for "ionic liquid"

Ionic Liquids as Homogeneous Catalysts for Glycerol Oligomerization

2022

Ionic liquids (ILs) were used for the first time as catalysts for the glycerin condensation reaction. A series of imidazolium and ammonium ionic liquids differing in the length of the alkyl substituent (C2, C12, and C14) and the type of anion (Br−, CH3COO−, and NaHPO4−) were synthesized using a typical two-step method. The structure of the obtained ILs was confirmed by nuclear magnetic resonance 13C NMR, and their base power was determined on the basis of the Hammett function. The oligomerization of glycerin with the participation of the obtained ionic liquids and, for comparison, in the presence of a homogeneous basic catalyst Na2CO3, was carried out for 3 h at 180 °C, under a pressure of …

Shaping 1,2,4-Triazolium Fluorinated Ionic Liquid Crystals

2023

The synthesis and thermotropic behaviour of some di-alkyloxy-phenyl-1,2,4-triazolium trifluoromethane-sulfonate salts bearing a seven-carbon atom perfluoroalkyl chain on the cation is herein described. The fluorinated salts presenting a 1,2,4-triazole as a core and differing in the length of two alkyloxy chains on the phenyl ring demonstrated a typical liquid crystalline behaviour. The mesomorphic properties of this set of salts were studied by differential scanning calorimetry and polarized optical microscopy. The thermotropic properties are discussed on the grounds of the tuneable structures of the salts. The results showed the existence of a monotropic, columnar, liquid crystalline phase…

Nośnikowy katalizator wanadocenowy z udziałem cieczy jonowych w polimeryzacji etylenu

2018

W pracy zsyntezowano szereg układów SILP z katalizatorem wanadocenowym – Cp2VCl2 poprzez immobilizację cieczy jonowych na różne rodzaje krzemionek, różniących się powierzchnią właściwą i wielkością porów, które modyfikowano wybranym związkiem glinoorganicznym – AlEtCl2 lub AlEt2Cl. Zsyntezowane układy analizowano metodami: FTIR, analiza elementarna, BET, AAS i SEM. Każdy z otrzymanych układów SILP był aktywny w polimeryzacji etylenu, niezależnie od ilości i rodzaju zastosowanego aktywatora (AlEtCl2 lub AlEt2Cl). Najwyższą aktywność w polimeryzacji etylenu osiągnięto wobec układu SILP z udziałem krzemionki o bardzo regularnej morfologii, gdzie do utworzenia etylochloroglinianowych anionów pi…

Palladium supported on cross-linked imidazolium network on silica as highly sustainable catalysts for the Suzuki reaction

2013

Bio-based chitosan and cellulose ionic liquid gels: polymeric soft materials for the desulfurization of fuel

2022

Desulfurization of fuel that avoids the introduction in the atmosphere of toxic sulfur volatile compounds, usually formed during combustion, is a viable strategy to reduce pollution. To find new efficient and eco-sustainable adsorbent materials, bio-based polymers such as chitosan (CS), cellulose (CE) and cellulose acetate (CEOAc) were dissolved in ionic liquids (ILs) to form ionic liquid gels (ILGs). Gelling and swelling ability, porosity, morphology, rheology and mechanical response were studied as a function of the polymer and ionic liquid (IL) used. The best performing gels were tested for fuel desulfurization using a fuel mimicking solution of thiophene (T), benzothiophene (BT) and dib…

Dicationic organic salts: gelators for ionic liquids

2014

Diimidazolium and dipyrrolidinium organic salts were tested for their ability to gel both organic solvents and ionic liquids. Organic salts containing 1-(1-imidazolylmethyl)-3,5-di-(3'-octylimidazolylmethyl)-benzene and 1-(N-pyrrolidylmethyl)-3,5-di-(N,N-octylpyrrolidylmethyl)-benzene cations were used. In addition to the simple bromide anion, also dianions having a naphthalene core such as 1,5- and 2,6-naphthalenedisulfonate and 2,6-naphthalenedicarboxylate were taken into account. Gelation tests demonstrated that organic salts used were able to harden ionic liquids. The materials obtained were investigated for their thermal stability and also for electric conductivity properties using mic…

A Study of Mechanical Properties of Polymer Composite Membranes with Various Ionic Liquids at Elevated Temperatures

2019

This work was supported by Latvian Council of Science (Cooperation project No.666/2014.4).

Wo3 and ionic liquids: A synergic pair for pollutant gas sensing and desulfurization

2020

This review deals with the notable results obtained by the synergy between ionic liquids (ILs) and WO3 in the field of pollutant gas sensing and sulfur removal pretreatment of fuels. Starting from the known characteristics of tungsten trioxide as catalytic material, many authors have proposed the use of ionic liquids in order to both direct WO3 production towards controllable nanostructures (nanorods, nanospheres, etc.) and to modify the metal oxide structure (incorporating ILs) in order to increase the gas adsorption ability and, thus, the catalytic efficiency. Moreover, ionic liquids are able to highly disperse WO3 in composites, thus enhancing the contact surface and the catalytic abilit…

Dissolution and hydrolysis of fibre sludge using hydroxyalkylimidazolium hydrogensulphate ionic liquids

2014

The dissolution and hydrolysis of wet fibre sludge in ionic liquids (ILs) with different reaction conditions are performed in this study. Novel types of hydroxyalkylimidazolium hydrogensulphate ILs, [glymim]HSO4, [hemim]HSO4 and [hpmim]HSO4, are especially designed and aimed to combine the dissolution and hydrolysis of wet fibre sludge in a one-step pretreatment. The results were obtained based on the analysis of total reducing sugars (TRS) with the DNS method. The dissolution and hydrolysis of fresh wild horse chestnut fruit (Aesculus hippocastanum) with the same ILs were also carried out as a comparison reference. Since fibre sludge is cellulose based and horse chestnut fruit is starch ba…

Green conditions for the Suzuki reaction using microwave irradiation and a new HNT- supported ionic liquid-like phase (HNT-SILLP) catalyst

2014

A new catalytic system based on modified halloysite nanotubes was employed in the Suzuki reaction under microwave irradi- ation. A set of solvents, times and bases was screened and the best experimental conditions were obtained when the reactions were carried out for 10 min in water–ethanol at 120 °C in presence of K2CO3 as base. Good recyclability was observed. The new catalytic system was employed using either 1 mol% or 0.1 mol%. The palladium catalyst displayed good activity, allowing the synthesis of several biphenyl compounds in high yield working with only 0.1 mol% palladium loading. The application of mi- crowave irradiation decreased the reaction time and also improved conversion wi…