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Ionic Liquids in Catalysis

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A special issue of Catalysts (ISSN 2073-4344).

Deadline for manuscript submissions: closed (31 January 2021) | Viewed by 39365

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Prof. Dr. Hieronim Maciejewski

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Faculty of Chemistry, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland
Interests: catalysis by transition metal complexes; catalysis in ionic liquids; synthesis, technologies, and modification of inorganic polymers; synthesis and applications of hybrid materials; technologies of organosilicon compounds

Special Issue Information

Dear Colleagues,

Ionic liquids (ILs), due to their distinctive properties, have attracted the interest of researchers for over 30 years. This interest has mainly been focused on their use as a green alternative to volatile organic solvents. The application of ILs as solvents in chemical reactions is well-documented in the literature and constitutes one of the oldest directions of studies on ionic liquids. The unique properties of ILs, particularly their high polarity, non-volatility, and high thermal stability, enable us to perform high temperature and pressure processes. However, they often act not only as solvents but also as catalysts, catalyst immobilizers, and initiators. A number of excellent review papers as well as books are devoted to these applications, particularly to the role played by ILs in catalysis. Over 100 types of chemical reactions are known in which ILs were successfully applied. Among them are reactions catalyzed by transition metal complexes, including hydrogenation, oxidation, hydroformylation, carbonylation, metathesis, and coupling reactions. In most cases, ILs can dissolve and immobilize metal complexes and, at the same time, they are insoluble in reactants, thus enabling us to perform processes in biphasic systems and to easily isolate products (after a reaction) with the possibility of reusing the catalytic system. In recent years, we have observed an intensive development of supported ionic liquid phase (SILP) technology. In these materials, transition metal complexes can be immobilized within a thin layer of IL deposited on a solid support, such as silica, activated carbon, and various mesoporous materials. The SILP concept has great potential for transition-metal-catalyzed processes, such as hydroformylation and carbonylation, and fine chemical syntheses. However, in addition to the application of ionic liquids as immobilizing agents, more and more frequently attempts are being made to obtain metal-ion-containing ionic liquids with catalytic properties, namely halometallate ionic liquids, NHC complexes, etc.

This Special Issue aims to show the most recent advances and trends in the design, synthesis, and characterization of catalysts based on ILs, as well as presenting their activity, mechanistic aspects, and potential for application.

Prof. Dr. Hieronim Maciejewski
Guest Editor

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Keywords

immobilization of TM complexes
supported ionic liquid phase
NHC complexes
halometallate ionic liquids
transformations in ionic liquids
stability of complexes in ionic liquids
catalytic activity
mechanistic aspects

Published Papers (13 papers)

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Editorial

Jump to: Research, Review

3 pages, 191 KiB

Open AccessEditorial

Ionic Liquids in Catalysis

by Hieronim Maciejewski

Catalysts 2021, 11(3), 367; https://doi.org/10.3390/catal11030367 - 11 Mar 2021

Cited by 20 | Viewed by 3004

Abstract

Ionic liquids play a larger and larger as well as more and more diversified role in catalysis [...] Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

Research

Jump to: Editorial, Review

12 pages, 1742 KiB

Open AccessCommunication

SILP Materials as Effective Catalysts in Selective Monofunctionalization of 1,1,3,3-Tetramethyldisiloxane

by Rafal Kukawka, Anna Pawlowska-Zygarowicz, Rafal Januszewski, Joanna Dzialkowska, Mariusz Pietrowski, Michal Zielinski, Hieronim Maciejewski and Marcin Smiglak

Catalysts 2020, 10(12), 1414; https://doi.org/10.3390/catal10121414 - 03 Dec 2020

Cited by 3 | Viewed by 2227

Abstract

Functionalized siloxanes are one of the most important classes of organosilicon compounds, thus the enhancement of current methods of its synthesis is an important issue. Herein, we present the selective and highly effective reaction between 1,1,3,3-tetramethyldisiloxane (TMDSO) and 1-octene (1-oct), using SILP (supported ionic liquid phase) materials containing a rhodium catalyst immobilized in three phosphonium ionic liquids (ILs) differing in the structure of cation. Studies have shown high potential for using SILP materials as catalysts due to their high catalytic activity and selectivity, easy separation process, and the possibility of reusing the catalyst in subsequent reaction cycles without adding a new portion of the catalyst. Using the most active SILP material SiO₂/[P₆₆₆₁₄][NTf₂]/[{Rh(μ-OSiMe₃)(cod)}₂] allows for reuse of the catalyst at least 50 times in an efficient and highly selective monofunctionalization of TMDSO. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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16 pages, 1823 KiB

Open AccessArticle

Valorization of Cellulose Recovered from WWTP Sludge to Added Value Levulinic Acid with a Brønsted Acidic Ionic Liquid

by Katarzyna Glińska, Clara Lerigoleur, Jaume Giralt, Esther Torrens and Christophe Bengoa

Catalysts 2020, 10(9), 1004; https://doi.org/10.3390/catal10091004 - 02 Sep 2020

Cited by 16 | Viewed by 2615

Abstract

The progressive decline of using fossil sources in the industry means that alternative resources must be found to produce chemicals. Waste biomass (sewage sludge) and waste lignocellulosic resources (food, forestry, or paper industries) are ideal candidates to take over from fossil sources. Municipal sewage sludge, and especially primary sludge, has a significant proportion of cellulose in its composition. Proper treatment of this cellulose allows the production of interesting chemicals like levulinic acid that are precursors (bio-blocks or building blocks) for other organic chemical processes. Cellulose was extracted from municipal wet primary sludge and paper industry dried sludge with a commercial ionic liquid. More than 99% of the cellulose has been recovered in both cases. Extraction was followed by the bleaching of the cellulose for its purification. In the bleaching, a large part of the ash was removed (up to 70% with municipal sludge). Finally, the purified cellulose was converted in levulinic acid by catalyzed hydrothermal liquefaction. The reaction, done at 170 °C and 7 bar, catalyzed by a tailored Brønsted acidic ionic liquid produced levulinic acid and other by-products in smaller quantities. The process had a conversion of cellulose to levulinic acid of 0.25 with municipal sludge and of 0.31 with industrial sludge. These results fully justify the process but, require further study to increase the conversion of cellulose to levulinic acid. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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18 pages, 5806 KiB

Open AccessArticle

Tuned Bis-Layered Supported Ionic Liquid Catalyst (SILCA) for Competitive Activity in the Heck Reaction of Iodobenzene and Butyl Acrylate

by Nemanja Vucetic, Pasi Virtanen, Ayat Nuri, Andrey Shchukarev, Jyri-Pekka Mikkola and Tapio Salmi

Catalysts 2020, 10(9), 963; https://doi.org/10.3390/catal10090963 - 22 Aug 2020

Cited by 2 | Viewed by 2676

Abstract

A thorough experimental optimization of supported ionic liquid catalyst (SILCA) was performed in order to obtain a stable and efficient catalyst for the Heck reaction. Out of fifteen proposed structures, propyl imidazolium bromide-tetramethylguanidinium pentanoate modified SiO₂ loaded with PdCl₂ appeared to be the most stable and to have a good activity in the reaction between butylacrylate and iodobezene, resulting in a complete conversion in 40 min at 100 °C, in four consecutive experiments. This study elucidated on the stability of the catalytic system with an ionic liquid layer during the catalyst synthesis but also under reaction conditions. In the bis-layered catalyst, the imidazolium moiety as a part of internal layer, brought rigidity to the structure, while in external layer pentanoic acid gave sufficiently acidic carboxylic group capable to coordinate 1,1,3,3-tetramethylguanidine (TMG) and thus, allow good dispersion of Pd nanoparticles. The catalyst was characterized by means of XPS, FT-IR, TEM, ICP-OES, ζ-potential, EDX, TGA, and ¹³C NMR. The release and catch mechanism was observed, whereas Pd re-deposition can be hindered by catalyst poisoning and eventual loss of palladium. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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17 pages, 1738 KiB

Open AccessArticle

Performance of 1-(3-Sulfopropyl)-3-Methylimidazolium Hydrogen Sulfate as a Catalyst for Hardwood Upgrading into Bio-Based Platform Chemicals

by Mar López, Sandra Rivas, Carlos Vila, Valentín Santos and Juan Carlos Parajó

Catalysts 2020, 10(8), 937; https://doi.org/10.3390/catal10080937 - 15 Aug 2020

Cited by 3 | Viewed by 2695

Abstract

The acidic ionic liquid 1-(3-sulfopropyl)-3-methylimidazolium hydrogen sulfate ([C3SO₃Hmim]HSO₄) was employed as a catalyst for manufacturing polysaccharide-derived products (soluble hemicellulose-derived saccharides, furans, and/or organic acids) from Eucalyptus globulus wood. Operation was performed in aqueous media supplemented with [C3SO₃Hmim]HSO₄ and methyl isobutyl ketone, following two different processing schemes: one-pot reaction or the solubilization of hemicelluloses by hydrothermal processing followed by the separate manufacture of the target compounds from both hemicellulose-derived saccharides and cellulose. Depending on the operational conditions, the one-pot reaction could be directed to the formation of furfural (at molar conversions up to 92.6%), levulinic acid (at molar conversions up to 45.8%), or mixtures of furfural and levulinic acid (at molar conversions up to 81.3% and 44.8%, respectively). In comparison, after hydrothermal processing, the liquid phase (containing hemicellulose-derived saccharides) yielded furfural at molar conversions near 78%, whereas levulinic acid was produced from the cellulose-enriched, solid phase at molar conversions up to 49.5%. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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14 pages, 1612 KiB

Open AccessFeature PaperArticle

Piperidinium and Pyrrolidinium Ionic Liquids as Precursors in the Synthesis of New Platinum Catalysts for Hydrosilylation

by Magdalena Jankowska-Wajda, Olga Bartlewicz, Przemysław Pietras and Hieronim Maciejewski

Catalysts 2020, 10(8), 919; https://doi.org/10.3390/catal10080919 - 10 Aug 2020

Cited by 7 | Viewed by 2701

Abstract

Six new air-stable anionic platinum complexes were synthesized in simple reactions of piperidinium [BMPip]Cl or pyrrolidinium [BMPyrr]Cl ionic liquids with platinum compounds ([Pt(cod)Cl₂] or K₂[PtCl₆]). All these compounds were subjected to isolation and spectrometric characterization using NMR and ESI-MS techniques. Furthermore, the determination of melting points and thermal stability of the above derivatives was performed with the use of thermogravimetric analysis. The catalytic performance of the synthesized complexes was tested in hydrosilylation of 1-octene and allyl glycidyl ether with 1,1,1,3,5,5,5-heptamethyltrisiloxane. The study has shown that they have high catalytic activity and are insoluble in the reaction medium which enabled them to isolate and reuse them in consecutive catalytic cycles. The most active complex [BMPip]₂[PtCl₆] makes it possible to conduct at least 10 catalytic runs without losing activity which makes it an attractive alternative not only to commonly used homogeneous catalysts, but also to heterogeneous catalysts for hydrosilylation processes. The activity of the studied catalysts is also affected by the kind of anion and, to some extent, the kind of cation. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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16 pages, 5951 KiB

Open AccessArticle

Beneficial Contribution of Biosourced Ionic Liquids and Microwaves in the Michael Reaction

by Katia Bacha, Kawther Aguibi, Jean-Pierre Mbakidi and Sandrine Bouquillon

Catalysts 2020, 10(8), 814; https://doi.org/10.3390/catal10080814 - 22 Jul 2020

Cited by 4 | Viewed by 2125

Abstract

We developed a synthesis of chiral ionic liquids from proline and one of its derivatives. Nine chiral ionic liquids were synthesized with yields from 78% to 95%. These synthesized ionic liquids played two roles in Michael reactions, as solvents, and as basic catalysts, where the ionic phase could also be reused at least five times without loss of activity. The yields up to 99% were improved by increasing the amount of dimethylmalonate from 1.2 equivalents to 3 or 4 equivalents. Furthermore, the reaction time could be reduced from 24 h to 45 min through microwaves activation. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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16 pages, 5398 KiB

Open AccessArticle

Ru-Catalyzed Repetitive Batch Borylative Coupling of Olefins in Ionic Liquids or Ionic Liquids/scCO₂ Systems

by Jakub Szyling, Tomasz Sokolnicki, Adrian Franczyk and Jędrzej Walkowiak

Catalysts 2020, 10(7), 762; https://doi.org/10.3390/catal10070762 - 08 Jul 2020

Cited by 4 | Viewed by 2266

Abstract

The first, recyclable protocol for the selective synthesis of (E)-alkenyl boronates via borylative coupling of olefins with vinylboronic acid pinacol ester in monophasic (cat@IL) or biphasic (cat@IL/scCO₂) systems is reported in this article. The efficient immobilization of [Ru(CO)Cl(H)(PCy₃)₂] (1 mol%) in [EMPyr][NTf₂] and [BMIm][OTf] with the subsequent extraction of products with n-heptane permitted multiple reuses of the catalyst without a significant decrease in its activity and stability (up to 7 runs). Utilization of scCO₂ as an extractant enabled a significant reduction in the amount of catalyst leaching during the separation process, compared to extraction with n-heptane. Such efficient catalyst immobilization allowed an intensification of the processes in terms of its productivity, which was indicated by high cumulative TON values (up to 956) in contrast to the traditional approach of applying volatile organic solvents (TON = ~50–100). The reaction was versatile to styrenes with electron-donating and withdrawing substituents and vinylcyclohexane, generating unsaturated organoboron compounds, of which synthetic utility was shown by the direct transformation of extracted products in iododeborylation and Suzuki coupling processes. All synthesized compounds were characterized using ¹H, ¹³C NMR and GC-MS, while leaching of the catalyst was detected with ICP-MS. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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12 pages, 1280 KiB

Open AccessArticle

Preparation of 5-HMF in a DES/Ethyl N-Butyrate Two-Phase System

by Jinyan Lang, Junliang Lu, Ping Lan, Na Wang, Hongyan Yang and Heng Zhang

Catalysts 2020, 10(6), 636; https://doi.org/10.3390/catal10060636 - 07 Jun 2020

Cited by 20 | Viewed by 3194

Abstract

In this paper, a two-phase system, formed by oxalic acid/choline chloride-based deep eutectic solvent (DES) and chosen extractants, was used as a dissolution–reaction–separation system, and metal chloride was used as a catalyst to study the degradation of cellulose to produce 5-hydroxymethylfurfural (5-HMF) and glucose. The effects of the amount of organic solvent and the reaction temperature on product yield, the repeated recycling of DES, the comparison between a two-phase system and a homogeneous system, and the mechanism of cellulose degradation to 5-HMF were investigated. The results show that ethyl n-butyrate has the best extraction effect on 5-HMF. Compared with the homogeneous system, the yield of 5-HMF and glucose in the two-phase system is significantly improved. At a temperature of 140 °C and a reaction time of 120 min, the yields of glucose and 5-HMF reached the maximum, which were 23.5% and 29.8%, respectively. After DES was reused three times, the yields of glucose and 5-HMF decreased greatly, indicating that the recycling rate of DES was low. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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14 pages, 979 KiB

Open AccessFeature PaperArticle

Highly Efficient and Reusable Alkyne Hydrosilylation Catalysts Based on Rhodium Complexes Ligated by Imidazolium-Substituted Phosphine

by Olga Bartlewicz, Magdalena Jankowska-Wajda and Hieronim Maciejewski

Catalysts 2020, 10(6), 608; https://doi.org/10.3390/catal10060608 - 01 Jun 2020

Cited by 6 | Viewed by 2863

Abstract

Rhodium complexes ligated by imidazolium-substituted phosphine were used as catalysts in the hydrosilylation of alkynes (1-heptyne, 1-octyne, and phenylacetylene) with 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMTS) or triethylsilane (TES). In all cases, the above complexes showed higher activity and selectivity compared to their precursors ([Rh(PPh₃)₃Cl] and [{Rh(µ-Cl)(cod)}₂]). In the reactions with aliphatic alkynes (both when HMTS and TES were used as hydrosilylating agents), β(Z) isomer was mainly formed, but, in the reaction of phenylacetylene with TES, the β(E) product was formed. The catalysts are very durable, stable in air and first and foremost insoluble in the reactants which facilitated their isolation and permitted their multiple use in subsequent catalytic runs. They make a very good alternative to the commonly used homogeneous catalysts. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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11 pages, 3785 KiB

Open AccessArticle

Sustainable Method for the Synthesis of Alternative Bis(2-Ethylhexyl) Terephthalate Plasticizer in the Presence of Protic Ionic Liquids

by Aleksander Grymel, Piotr Latos, Karolina Matuszek, Karol Erfurt, Natalia Barteczko, Ewa Pankalla and Anna Chrobok

Catalysts 2020, 10(4), 457; https://doi.org/10.3390/catal10040457 - 23 Apr 2020

Cited by 7 | Viewed by 3887

Abstract

Inexpensive Brønsted acidic ionic liquids based on trimethylamine and sulfuric acid are proposed as both solvents and catalysts in the synthesis of alternative plasticizer bis(2-ethylhexyl) terephthalate, which has a broad spectrum of applications in plasticization processes. The utilization of 50 mol % of Brønsted ionic liquid led to the full conversion of terephthalic acid after 8 h of reaction at 120 °C. Additionally, a 100% selectivity of bis(2-ethylhexyl) terephthalate was obtained. The advantage of the presented reaction system is based on the formation of a biphasic system during the reaction. The bottom phase consists of an ionic liquid and water, and the upper phase is created by the ester and unreacted alcohol. This phenomenon helps overcome the equilibrium of the reaction and drives it towards a high yield of product. The presented new approach is proposed as a safe, cost-effective, and alternative method to conventional processes with organometallic compounds that, in turn, leads to greener and a more economically viable technology. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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13 pages, 2914 KiB

Open AccessArticle

N-Hydroxyphthalimide Supported on Silica Coated with Ionic Liquids Containing CoCl₂ (SCILLs) as New Catalytic System for Solvent-Free Ethylbenzene Oxidation

by Gabriela Dobras, Kornela Kasperczyk, Sebastian Jurczyk and Beata Orlińska

Catalysts 2020, 10(2), 252; https://doi.org/10.3390/catal10020252 - 19 Feb 2020

Cited by 21 | Viewed by 3429

Abstract

N-Hydroxyphthalimide was immobilized via ester bond on commercially available silica gel (SiOCONHPI) and then coated with various ionic liquids containing dissolved CoCl₂ (SiOCONHPI@CoCl₂@IL). New catalysts were characterized by means of FT IR spectroscopy, elemental analysis, SEM and TGA analysis and used in ethylbenzene oxidation with oxygen under mild solvent-free conditions (80 °C, 0.1 MPa). High catalytic activity of SiOCONHPI was proved. In comparison to a non-catalytic reaction, a two-fold increase in conversion of ethylbenzene was observed (from 4.7% to 8.6%). Coating of SiOCONHPI with [bmim][OcOSO₃], [bmim][Cl] and [bmim][CF₃SO₃] containing CoCl₂ enabled to increase the catalytic activity in relation to systems in which IL and CoCl₂ were added directly to reaction mixture. The highest conversion of ethylbenzene was obtained while SiOCONHPI@CoCl₂@[bmim][OcOSO₃] were used (12.1%). Catalysts recovery and reuse was also studied. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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Review

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20 pages, 1892 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Heterogeneous Catalysis with the Participation of Ionic Liquids

by Olga Bartlewicz, Izabela Dąbek, Anna Szymańska and Hieronim Maciejewski

Catalysts 2020, 10(11), 1227; https://doi.org/10.3390/catal10111227 - 22 Oct 2020

Cited by 42 | Viewed by 4518

Abstract

This mini-review briefly describes the recent progress in the design and development of catalysts based on the presence of ionic liquids. In particular, the focus was on heterogeneous systems (supported ionic liquid (IL) phase catalysts (SILPC), solid catalysts with ILs (SCILL), porous liquids), which due to the low amounts of ionic liquids needed for their production, eliminate basic problems observed in the case of the employment of ionic liquids in homogeneous systems, such as high price, high viscosity, and efficient isolation from post-reaction mixtures. Full article

(This article belongs to the Special Issue Ionic Liquids in Catalysis)

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