Search

As glucose biosensors play an important role in glycemic control, which can prevent the diabetic complications, the development of a glucose sensing platform is still in needed. Herein, the first proposal on the in-house fabricated paper-based screen-printed ionic liquid/graphene electrode (SPIL-GE) modified with MXene (Ti3C2Tx), prussian blue (PB), glucose oxidase (GOx), and Nafion is reported. The concentration of PB/Ti3C2Tx was optimized and the optimal detection potential of PB/Ti3C2Tx/GOx/Nafion/SPIL-GE is −0.05 V. The performance of PB/Ti3C2Tx/GOx/Nafion modified SPIL-GE was characterized by cyclic voltammetry and chronoamperometry technique. This paper-based platform integrated with nanomaterial composites were realized for glucose in the range of 0.0–15.0 mM with the correlation coefficient R2 = 0.9937. The limit of detection method and limit of quantification were 24.5 μM and 81.7 μM, respectively. In the method comparison, this PB/Ti3C2Tx/GOx/Nafion/SPIL-GE exhibits a good correlation with the reference hexokinase method. This novel glucose sensing platform can potentially be used for the good practice to enhance the sensitivity and open the opportunity to develop paper-based electroanalytical devices.

Weighing paper-assisted magnetic ionic liquid headspace single-drop microextraction using microwave distillation followed by gas chromatography-mass spectrometry was successfully developed to determine the essential oil components in lavender. The magnetic ionic liquid 1-octyl-3-methylimidazolium tetrachloroferrate was successfully synthesized and used as the optimal extraction solvent. An aliquot of 9 μL of magnetic ionic liquid could be stably suspended on the weighing paper for long time extraction. The increase of the extractant volume resulted in a significantly enhanced in extracting efficiency of the weighing paper-assisted magnetic ionic liquid headspace single-drop microextraction than traditional headspace single-drop microextraction method. In this experiment, the optimal conditions were 1-octyl-3-methylimidazolium tetrachloroferrate as the extraction solvent, extraction time of 12 min, microwave power of 600 W, cyclohexane as back-extractant and sample amount of 30 mg. The developed method was successfully applied to analyze 16 lavender samples from three different harvest years. A total of 39 compounds in lavender were identified and the principal component analysis provided a clear separation between those lavender samples harvested in different years. The results indicated that the proposed weighing paper-assisted magnetic ionic liquid headspace single-drop microextraction is a novel, fast, simple and sensitive microextration technique for the determination of the essential oil components in lavender.

Composite adsorbents based on metal-organic frameworks (MOFs) are excellent candidates for solid-phase extraction (SPE) due to their diverse chemical functionality and multilevel porosity. MOF superstructures based on self-assembly at room temperature (RT) could have less energy consumption and easier manipulation due to the larger complex geometry. The π-π stacking of the benzene ring could not only enhance the interaction toward hydrophobic or plane-structured targets but also be expected to promote the formation of the MOF superstructure. In this work, in the established RT self-assembly synthesis system, several factors were investigated to see how to obtain functional MOF superstructures with a regular geometry, among which the number of benzene rings in the ligand was mainly tested for its impact on self-assembly and adsorption capacity. By means of adsorption experiments and computational fluid dynamics (CFD) simulation, the relationship between structure and activity (SARs) was further explored. Interestingly, the MOF unit with the lowest specific surface area performed the best in adsorption. Then, the selected functional MOF superstructure and ionic liquid were used to produce the composite paper membrane facilely applied in the SPE device. After optimization of the preparation conditions and operation parameters, the established SPE-HPLC-UV method could selectively analyze tetracycline-like antibiotics in the range of 16.6-833.3 ng/g (ppb) in a meat sample. This work provided an RT synthesis method to produce a microsize MOF superstructure, with experimental and theoretical insights into the SARs, which could be expanded in the design of other MOF-based SPE composite membranes toward one group of analogues.

Recently, pharmaceuticals and personal care products in the water environment exhibited potential risks to both human and aquatic organisms. In order to improve the sensitivity and accuracy of pharmaceutical detection, the polyimidazolyl acetate ionic liquid was synthesized by Radziszewski reaction and coated on cellulose filter papers as a thin-film extraction phase for extraction of non-steroidal anti-inflammatory drugs from water. The attenuated total reflection-infrared spectrometry, thermogravimetric analysis, and scanning electron microscope analyses demonstrated that the polyimidazolyl acetate ionic liquid was successfully prepared and attached to the surface of the cellulose filter paper through chemical bonding. The adsorption capacity of the homemade thin-film extraction material for the four non-steroidal anti-inflammatory drugs was greater than 8898 ng/cm

Researchers have been exploring dielectric testing techniques both in time and frequency domain for insulation condition assessment of oil-paper insulated transformers. In a practical dielectric system, dipoles are found to behave according to a distribution of elementary Debye relaxation properties. Suitable distribution density functions have been proposed to characterise such many-body interaction processes. Cole–Cole diagrams can be one of the methods for studying the nature of frequency dependency of dielectric materials of complex structure. Cole–Cole plots are commonly used for characterising different materials such as dielectric mixtures, ionic liquids, cable insulating oil, polar liquids etc. The scope of its application for assessing transformer oil-paper insulation considering distributed relaxation process has not been explored yet. The present contribution discusses mathematical formulations used for transforming the experimentally obtained time domain dielectric response test data to distribution domain and further to frequency domain for obtaining the Cole–Cole plots. Findings about the influence of various operating conditions and insulation status on the Cole–Cole diagram have been reported in this contribution. Results of tests on field transformers are also presented. This paper attempts to employ the features of Cole–Cole diagrams as potential indicators for analysing condition of the oil-paper insulation considering distributed relaxation process.

A sensitive, rapid and efficient ionic liquid-based vortex assisted liquid-liquid microextraction (IL-VALLME) with Liquid Chromatography Mass spectrometry (LC-MS/MS) method is proposed for the determination of bisphenols in thermal paper. Extraction factors were systematically optimized by response surface methodology. Experimental factors showing significant effects on the analytical responses were evaluated using design of experiment. The limit of detection for Bisphenol-A (BPA) and Bisphenol-S (BPS) in thermal paper were 1.25 and 0.93μgkg-1 respectively. The dynamic linearity range for BPA was between 4 and 100μgkg-1 and the determination of coefficient (R2) was 0.996. The values of the same parameters were 3-100μgkg-1 and 0.998 for BPS. The extraction recoveries of BPA and BPS in thermal paper were 101% and 99%. Percent relative standard deviation (% RSD) for matrix effect and matrix match effects were not more than 10%, for both bisphenols. The proposed method uses a statistical approach for the analysis of bisphenols in environmental samples, and is easy, rapid, requires minimum organic solvents and efficient.

A new planar sorptive phase based on the simple immobilization of polymeric ionic liquids on paper is proposed. The sorptive phase can develop hydrophobic or mixed-mode (combining hydrophobic and ion exchange) interactions with the target analytes. The polymer is prepared by the Radziszewski reaction, which takes place in aqueous media, and it has been thoroughly characterized by different techniques including infrared spectroscopy, matrix-assisted laser desorption/ionization coupled to high-resolution mass spectrometry and proton nuclear magnetic resonance. Three different strategies aimed to immobilize the polymeric ionic liquid on paper have been evaluated. Among them, simple thermal curing at 120 °C was selected. The as-prepared paper has been evaluated for the extraction of several non-steroidal anti-inflammatory drugs from urine, the analytes being finally determined by liquid chromatography with tandem mass spectrometry. The method detection limits were 3.8, 7.2, 6.8, 9.4, 15.7, and 5.1 μg/L for indomethacin, diclofenac, tolmetin, ketoprofen, naproxen, and ibuprofen, respectively. Calibration models were linear (R2 > 0.9949) up to 1000 μg/L. The intra-day precision, expressed as relative standard deviation and calculated at three different concentrations levels (limit of quantification, 250 μg/L, and 1000 μg/L), varied between 1.1 and 13%. The accuracy, calculated as relative recovery, was in the range from 72 to 95%, thus being considered appropriate. The easiness of polymeric ionic liquid paper synthesis and the multi-sample extraction protocol designed allows the processing of a high number of samples at the same time.

A paper-based analytical device (PAD) with an integrated composite electrode for non-enzymatic creatinine sensing was developed. The electrode was produced and optimization was efficiently accomplished using a rapid digital dispensing approach. The electrochemical sensor was fabricated using an HP D300 digital dispenser to deliver a copper oxide and ionic liquid composite onto an electrochemically reduced graphene modified screen-printed carbon electrode (CuO/IL/ERGO/SPCE) on a PAD. The modified electrode was characterized using electrochemical and microscopic techniques. Electrochemical detection of creatinine was performed on the SPCE using amperometry at a constant potential. Under optimized conditions, the paper-based sensor exhibited a linear range of 0.01–2.0 mM (R2 = 0.99) and the limit of detection was 0.22 μM (S/N = 3, IUPAC definition) for creatinine. The simple fabrication process, low cost, and clinically appropriate creatinine sensitivity make this device applicable for point-of-care use.

Industrial wastewaters and their treatment are now placed at the heart of the environmental concerns that industries face. Some research work has been carried out in order to limit the impact of these wastes on the environment as well as their costs. In this study, wastewater dehydrated sludge (55% wt. water content) from the paper industry was used to recover cellulose by using tetrakis(hydroxymethyl)phosphonium chloride, [P(CH2OH)4]Cl, ionic liquid as a solvent. The ionic liquid has shown remarkable results in terms of cellulose extraction in addition to its non-volatility and lower toxicity compared to organic volatile solvents. All cellulose, based on dry sludge, was recovered from the industrial dehydrated sludge with better operation conditions. The influence of temperature and the quantity of ionic liquid was preliminary studied in order to optimise the extraction conditions.

Based on the tunability of ionic liquids (ILs) according to the specific requirement of an application, 1-dodecylimidazolium chloride with amphiphilic structures was chemically fabricated on the surface of filter papers (DIL-FPs) for the first time. After synthesis, DIL-FPs was characterized by scanning electronic microscopy, energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. DIL-FPs was used as a novel thin-film microextraction (TFME) phase for the preconcentration of amphiphilic bisphenol A from plant oil samples. The related extraction variables were studied in a spiked sunflower seed oil. Under the optimal conditions, the linear range was 5.0 - 1000 μg L-1 with a correlation coefficient of 0.9976. The limit of detection (S/N = 3) and the enrichment factor of the proposed method were 2.7 μg L-1 and 118, respectively. The intra-day precision and inter-day precision for six repeated determinations were 2.3 and 4.9%, respectively. These plant oil samples used in this work were free of bisphenol A contaminations. The recovery study carried out in different plant oil samples and mean recoveries ranged from 77.16 to 97.10%. The developed DIL-FPs extraction film phase followed by HPLC-UV provides a potential pretreatment strategy for the analysis of weak organic acid compounds in plant oil samples.

A facile electrochemical exfoliation method was established to efficiently prepare conductive paper containing reduced graphene oxide (RGO) with the help of single chain anionic surfactant ionic liquids (SAILs). The surfactant ionic liquids are synthesized from conventional organic surfactant anions and a 1-butyl-3-methyl-imidazolium cation. For the first time the combination of SAILs and cellulose was used to directly exfoliate graphite. The ionic liquid 1-butyl-3-methyl-imidazolium dodecylbenzenesulfonate (BMIM-DBS) was shown to have notable affinity for graphene, demonstrating improved electrical properties of the conductive cellulose paper. The presence of BMIM-DBS in the system promotes five orders of magnitude enhancement of the paper electrical conductivity (2.71 × 10−5 S cm−1) compared to the native cellulose (1.97 × 10−10 S cm−1). A thorough investigation using electron microscopy and Raman spectroscopy highlights the presence of uniform graphene incorporated inside the matrices. Studies into aqueous aggregation behavior using small-angle neutron scattering (SANS) point to the ability of this compound to act as a bridge between graphene and cellulose, and is responsible for the enhanced exfoliation level and stabilization of the resulting dispersion. The simple and feasible process for producing conductive paper described here is attractive for the possibility of scaling-up this technique for mass production of conductive composites containing graphene or other layered materials.

We introduce for the first time a paper-based analytical device (PAD) for the non-enzymatic detection of glucose by modifying a screen-printed carbon electrode with cobalt phthalocyanine, graphene and an ionic liquid (CoPc/G/IL/SPCE). The modifying composite was characterized by UV-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The disposable devices show excellent conductivity and fast electron transfer kinetics. The results demonstrated that the modified electrode on PADs had excellent electrocatalytic activity towards the oxidation of glucose with NaOH as supporting electrolyte (0.1M). The oxidation potential of glucose was negatively shifted to 0.64V vs. the screen-printed carbon pseudo-reference electrode. The paper-based sensor comprised a wide linear concentration range for glucose, from 0.01 to 1.3mM and 1.3-5.0mM for low and high concentration of glucose assay, respectively, with a detection limit of 0.67µM (S/N = 3). Additionally, the PADs were applied to quantify glucose in honey, white wine and human serum. The disposable, efficient, sensitive and low-cost non-enzymatic PAD has great potential for the development of point-of-care testing (POCT) devices that can be applied in healthcare monitoring.

A sensitive and fast-responding membrane-free amperometric gas sensor is described, consisting of a small filter paper foil soaked with a room temperature ionic liquid (RTIL), upon which three electrodes are screen printed with carbon ink, using a suitable mask. It takes advantage of the high electrical conductivity and negligible vapour pressure of RTILs as well as their easy immobilization into a porous and inexpensive supporting material such as paper. Moreover, thanks to a careful control of the preparation procedure, a very close contact between the RTIL and electrode material can be achieved so as to allow gaseous analytes to undergo charge transfer just as soon as they reach the three-phase sites where the electrode material, paper supported RTIL and gas phase meet. Thus, the adverse effect on recorded currents of slow steps such as analyte diffusion and dissolution in a solvent is avoided. To evaluate the performance of this device, it was used as a wall-jet amperometric detector for flow injection analysis of 1-butanethiol vapours, adopted as the model gaseous analyte, present in headspace samples in equilibrium with aqueous solutions at controlled concentrations. With this purpose, the RTIL soaked paper electrochemical detector (RTIL-PED) was assembled by using 1-butyl-3- methylimidazolium bis(trifluoromethanesulfonyl)imide as the wicking RTIL and printing the working electrode with carbon ink doped with cobalt(ii) phthalocyanine, to profit from its ability to electrocatalyze thiol oxidation. The results obtained were quite satisfactory (detection limit: 0.5 ?M; dynamic range: 2-200 ?M, both referring to solution concentrations; correlation coefficient: 0.998; repeatability: ±7% RSD; long-term stability: 9%), thus suggesting the possible use of this device for manifold applications. © 2012 The Royal Society of Chemistry.

Hydrothermal carbonization followed by chemical activation is utilized to convert paper pulp mill sludge biowaste into high surface area (up to 2980 m2 g-1) carbons. This synthesis process employs an otherwise unusable byproduct of paper manufacturing that is generated in thousands of tons per year. The textural properties of the carbons are tunable by the activation process, yielding controlled levels of micro and mesoporosity. The electrochemical results for the optimized carbon are very promising. An organic electrolyte yields a maximum capacitance of 166 F g-1, and a Ragone curve with 30 W h kg-1 at 57 W kg-1 and 20 W h kg-1 at 5450 W kg-1. Two ionic liquid electrolytes result in maximum capacitances of 180-190 F g-1 with up to 62% retention between 2 and 200 mV s-1. The ionic liquids yielded energy density-power density combinations of 51 W h kg-1 at 375 W kg -1 and 26-31 W h kg-1 at 6760-7000 W kg-1. After 5000 plus charge-discharge cycles the capacitance retention is as high at 91%. The scan rate dependence of the surface area normalized capacitance highlights the rich interplay of the electrolyte ions with pores of various sizes. © 2013 Elsevier Ltd. All rights reserved.

Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL–graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors.

The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene-carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene-CNT-IL nanocomposite (graphene-CNT-IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene-CNT-IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene-CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties.

Cellulose extracted from printed paper wastes were selectively depolymerized under controlled conditions into cello-oligomers of controllable chain lengths via dissolution in an ionic liquid, 1-allyl-3-methylimidazolium chloride (AMIMCl), and in the presence of an acid catalyst, Amberlyst 15DRY. The depolymerization process was optimized against reaction temperature, concentration of acid catalyst, and reaction time. Despite rapid initial depolymerization process, the rate of cellulose depolymerization slowed down gradually upon prolonged reaction time, with 75.0 wt% yield of regenerated cello-oligomers (mean Viscosimetric Degree of Polymerization value of 81) obtained after 40 min. The depolymerization of cellulose fibers at 80 °C appeared to proceed via a second-order kinetic reaction with respect to the catalyst concentration of 0.23 mmol H3O(+). As such, the cellulose depolymerization process could afford some degree of control on the degree of polymerization or chain lengths of cello-oligomers formed.

A low-cost, simple, portable and sensitive paper-based electrochemical sensor was established for the detection of K-562 cell in point-of-care testing. The hybrid material of 3D Au nanoparticles/graphene (3D Au NPs/GN) with high specific surface area and ionic liquid (IL) with widened electrochemical windows improved the good biocompatibility and high conductivity was modified on paper working electrode (PWE) by the classic assembly method and then employed as the sensing surface. IL could not only enhance the electron transfer ability but also provide sensing recognition interface for the conjugation of Con A with cells, with the cell capture efficiency and the sensitivity of biosensor strengthened simultaneously. Concanavalin A (Con A) immobilization matrix was used to capture cells. As proof-of-concept, the paper-based electrochemical sensor for the detection of K-562 cells was developed. With such sandwich-type assay format, K-562 cells as model cells were captured on the surface of Con A/IL/3D AuNPs@GN/PWE. Con A-labeled dendritic PdAg NPs were captured on the surface of K-562 cells. Such dendritic PdAg NPs worked as catalysts promoting the oxidation of thionine (TH) by H2O2 which was released from K-562 cells via the stimulation of phorbol 12-myristate-13-acetate (PMA). Therefore, the current signal response was dependent on the amount of PdAg NPs and the concentration of H2O2, the latter of which corresponded with the releasing amount from cells. So, the detection method of K-562 cell was also developed. Under optimized experimental conditions, 1.5×10(-14) mol of H2O2 releasing from each cell was calculated. The linear range and the detection limit for K-562 cells were determined to be 1.0×10(3)-5.0×10(6) cells/mL and 200 cells/mL, respectively. Such as-prepared sensor showed excellent analytical performance with good fabrication reproducibility, acceptable precision and satisfied accuracy, providing a novel protocol in point-of-care testing of cells.

Early industrialization and the development of cheap production processes for paper have led to an exponential accumulation of paper-based documents during the last two centuries. Archives and libraries harbor vast amounts of ancient and modern documents and have to undertake extensive endeavors to protect them from abiotic and biotic deterioration. While services for mechanical preservation such as ex post de-acidification of historic documents are already commercially available, the possibilities for long-term protection of paper-based documents against fungal attack (apart from temperature and humidity control) are very limited. Novel processes for mechanical enhancement of damaged cellulosic documents use Ionic Liquids (IL) as essential process components. With some of these ILs having azole-functionalities similar to well-known fungicides such as Clotrimazole, the possibility of antifungal activities of these ILs was proposed but has not yet been experimentally confirmed.We evaluated the potency of four ILs with potential application in paper restoration for suppression of fungal growth on five relevant paper-infesting molds. The results revealed a general antifungal activity of all ILs, which increased with the size of the non-polar group. Physiological experiments and ultimate elemental analysis allowed to determine the minimal inhibitory concentration of each IL as well as the residual IL concentration in process-treated paper. These results provide valuable guidelines for IL-applications in paper restoration processes with antifungal activity as an added benefit. With azoles remaining in the paper after the process, simultaneous repair and biotic protection in treated documents could be facilitated.

A prototype of a fast-response task-specific amperometric gas sensor based on paper-supported room-temperature ionic liquids (RTILs) is proposed here for improved analysis of volatile acid species. It consists of a small filter paper foil soaked with a RTIL mixture containing an ionic liquid whose anion (acetate) displays a basic character, upon which three electrodes are screen printed by carbon ink profiting from a suitable mask. It takes advantage of the high electrical conductivity and negligible vapour pressure of RTILs and of their easy immobilization into a porous and inexpensive supporting material such as paper. The performance of this device, used as a wall-jet amperometric detector for flow injection analyses of headspace samples in equilibrium with aqueous solutions at controlled concentrations, was evaluated for phenol and 1-butanethiol vapours which were adopted as model acid gaseous analytes. The results obtained showed that the quite high potentials required for the detection of these analytes are lowered significantly, thanks to the addition of the basic acetate RTIL. In such a way, overlap with the medium discharge is avoided, and the possible adverse effect of interfering species is minimised. The sensor performance was quite satisfactory (detection limits, ca. 0.3 μM; dynamic range, ca. 1–200 μM, both referred to solution concentrations; correlation coefficients in the range 0.993–0.997; repeatability, ± 6 % RSD; long-term stability, 9 %); thus suggesting the possible use of this device for manifold applications.

A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

Cellulose has received much attention as a emerging smart material, named as electro-active paper (EAPap), which can produce a large bending displacement with applied external electrical field. In spite of many advantages over other reported electro active polymers, there are some issues to be addressed: its actuator performance: (i) sensitive to environmental humidity, (ii) humidity dependent displacement output of the actuator and (iii) degradation of performance with time. In present paper, we have successfully developed the highly durable EAPap actuator working at ambient condition with large displacement output. To improve the performance and durability of EAPap, nanoscaled PPy layer into cellulose EAPap was formed by in-situ polymerization technique. Cellulose-PPy-IL nanocomposite based EAPap actuator showed nearly 100% improvement of the actuator performance compared that of pure cellulose based EAPap actuator systems.

Why not consider liquid salt forms of active pharmaceutical ingredients (APIs) as an alternative versatile tool in the pharmaceutical industry? Recent developments have shown that known APIs can be readily converted into ionic liquids and that these novel phases often possess different properties (e.g., improved solubilities and dissolution rates), which may have a direct impact on the pharmacokinetics and pharmacodynamics of the drug. They may also offer the potential of novel and more efficient delivery modes, as well as patent protection for each of the new forms of the drug. Since these pharmaceutically active ionic liquids represent a thermodynamically stable phase, they avoid the troublesome issues surrounding polymorphism and "polymorphic transformation." In some cases, an active cation and an active anion can be combined to produce a liquid possessing dual functionality. Here we examine and challenge the current industry reliance on crystalline APIs by discussing the breadth and potential impact of liquid salts as a possible approach to phase control.

This work reported the rapid in situ detection of ultratrace 2,4-dinitrotoluene (DNT) solids on various substrates by a sandwiched paper-like electrochemical sensor. The sensor, prepared by a simple electroless deposition method without using special instruments, possessed a unique thin-film structure of an insulated polyvinylidene fluoride (PVDF) membrane in between two gold (Au) conducting layers. The resulting gold-PVDF sandwich (GPVDFS) array exhibited excellent flexibility, porosity and electrochemical performance as a highly integrated dual-electrode sensor platform. The infiltration of nonvolatile ionic liquid (IL) electrolytes containing ferrocene (Fc) into the GPVDFS array produced a paper-like electrochemical sensor, which can directly detect ultratrace DNT solids on various substrate surfaces (e.g., plant leaves, gloves and metal knives) with detection limit as low as 0.33 ng/mm(2). The critical role of Fc in the detection of DNT at this dual-electrode sensor was explored. The compensating electrochemical oxidation of Fc at the counter/reference electrode was found to be essential to the reduction of DNT at the working electrode when IL electrolytes were employed. The present work thus demonstrated the promising applications of paper-based porous electrode arrays in developing IL-based electrochemical sensors for the in situ detection of analyte solids in complicated environments.

In this study, we investigate the “chemical welding” of paper with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) using a two-step process. First, the IL is transported into the structure of the paper as a water solution. Then, partial dissolution is achieved by activation with heat (80–95 °C), where the water evaporates and the surfaces of the fibres partially dissolve. The activated paper is washed with water to remove IL, and dried to fuse fibre surfaces into each other. The “chemically welded” paper structure has both elevated dry and wet strength. The treatment conditions can be adjusted to produce both paper-like materials and films. The most severe treatment conditions produce films that are fully transparent and their oxygen and grease barrier properties are excellent. As an all-cellulose material, the “chemically welded” paper is fully biodegradable and is a potential alternative to fossil fuel-based plastics.

Iron gall inks have been known since Roman times, were widely used in the Medieval Age, and became the most used ink in the Renaissance period. They were still officially used by the German Government as recently as 1973. The two main constituents of the ink are tannic acid and ferrous sulfate (vitriol). The vitriol normally used was not very pure and likely contained a mixture of iron sulfate with traces of other metals, in particular, copper. Certain transition-metal ions contained in iron gall inks and their acidity are known to deteriorate paper. Therefore, stabilization treatments consist of deacidification and the addition of antioxidants. To this end, the use of tetraalkylammonium bromides was recently proposed. Here, it is shown that 1-butyl-2,3-dimethylimidazolium bromide both in aqueous and in alcoholic solution can prevent the oxidative deterioration of cellulose. Furthermore, it does not lead to the yellowing of paper nor does it significantly affect the colour of the ink.

Paper material consists of fibres bound primarily with hydrogen bonds. Thus water can disrupt those bonds, making paper to be non-water-resistant, if no any wet strength agent is used. In this study, we investigated the "chemical welding" of kraft-pulp-paper with the ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc). The process was in two steps. Firstly, ionic liquid was transported into the paper structure. In the second phase, the dissolution and subsequent embedding of the fibre surfaces were achieved by the heat activation (80–95ºC). The IL treated paper was purified with water from IL and dried under compression. Precipitation of the dissolved cellulose resulted in a fusion of the fibres of paper into a solid, uniform material, whose properties are similar to thermoset plastics. Such obtained "chemically welded" paper structure elevated both dry and wet strength. The treatment conditions can be adjusted (i.e. dosage of ionic liquid, activation temperature, time) to produce both paper-like materials and films. The most severe treatment conditions produce films, which are fully transparent and whose oxygen and grease barrier properties are excellent. This study demonstrates conversion of ordinary paper into novel materials. As an all-cellulose material, the "chemically welded" paper is fully biodegradable and is a potential alternative to fossil fuel-based plastics.

The large electrochemical and cycling stability of “water‐in‐salt” systems have rendered promising prospective electrolytes for batteries. The impact of addition of water on the properties of ionic liquids has already been addressed in several publications. In this contribution, we focus on the changes in the state of water. Therefore, we investigated the protic ionic liquid N‐butyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide with varying water content at different temperatures with the aid of molecular dynamics simulations. It is revealed that at very low concentrations, the water is well dispersed and best characterized as shared solvent molecules. At higher concentrations, the water forms larger aggregates and is increasingly approaching a bulk‐like state. While the librational and rotational dynamics of the water molecules become faster with increasing concentration, the translational dynamics are found to become slower. Further, all dynamics are found to be faster if the temperature increases. The trends of these findings are well in line with the experimental measured conductivities., From single molecules to bulk liquid: The state of water in a protic ionic liquid at different concentration is investigated by the aid of molecular dynamics simulations. At a low concentration, the water shows the behavior of free molecules. With increasing concentration, the formation of clusters can be observed. Finally, at concentrations near the phase separation the behavior approaches that of the bulk liquid.

Ionic liquids are used in different processes owing to their low vapor pressure, large viscosity range, chemical and thermal stability, and superior conductance even without water. These features make them flexible and tunable, indicating their possible use as substitutes for commonly used compounds in many processes. The objective of this study was to evaluate the properties of aqueous binary solutions for three different ionic liquids (ILs): dibutylammonium acetate, dibutylammonium propanoate, and dibutylammonium butanoate. The measured properties were density, speed of sound, and conductivity, and their isentropic compressibility and thermal expansion coefficient were calculated based on these properties. The temperature range used for measurements was 293.15–323.15 K. Mathematical models were used for each ionic liquid + water mixture to fit the density and speed of sound data. The increase in the alkyl chain leads to a tendency to decrease the values of density, speed of sound, and conductivity of the solutions. However, decreasing the dilution in water, the density, the conductivity and the speed of sound initially increase and then decrease, exhibiting a maximum in the initial water concentration range which indicates the formation of aggregates. Critical micellar concentrations at 298 K were determined through conductivity data. Enhancing the temperature leads to a decrease on density and sound velocity. Supplementary Information The online version contains supplementary material available at 10.1007/s43153-021-00174-7.

Thirteen N‐butylpyridinium salts, including three monometallic [C4Py]2[MCl4], nine bimetallic [C4Py]2[M1−x aMx bCl4] and one trimetallic compound [C4Py]2[M1−y‐z aMy bMz cCl4] (M=Co, Cu, Mn; x=0.25, 0.50 or 0.75 and y=z=0.33), were synthesized and their structure and thermal and electrochemical properties were studied. All compounds are ionic liquids (ILs) with melting points between 69 and 93 °C. X‐ray diffraction proves that all ILs are isostructural. The conductivity at room temperature is between 10−4 and 10−8 S cm−1. Some Cu‐based ILs reach conductivities of 10−2 S cm−1, which is, however, probably due to IL dec. This correlates with the optical bandgap measurements indicating the formation of large bandgap semiconductors. At elevated temperatures approaching the melting points, the conductivities reach up to 1.47×10−1 S cm−1 at 70 °C. The electrochemical stability windows of the ILs are between 2.5 and 3.0 V., Mixed metal tetrahalidometallate ionic liquids (ILs) were for the first time synthesized and studied for their structural, optical, and electrochemical properties. The ILs exhibit high conductivities and tunable optical absorption and are thus novel and highly versatile candidates for application in electronic and optical devices.

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC4 Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).

U okviru ove disertacije uspešno je sintetisano 14 novih protičnih jonskih tečnosti na bazi amina. Strukture su potvrđene snimanjem NMR i IC spektra. Izmerena je gustina svih jonskih tečnosti u temperaturnom opsegu T = (293,15 – 353,15) K, kao i gustina njihovih vodenih rastvora u temperaturnom opsegu T = (293,15 – 313,15) K. Fizičko-hemijska karakterizacija je takođe propraćena merenjem viskoznosti i električne provodljivosti binarnih smeša u celom rasponu molarnih frakcija i na različitim temperaturama (T = (293,15 – 313,15) K). Na osnovu dobijenih rezultata utvrđeno je da sve protične jonske tečnosti imaju izražen structure making efekat. Ispitana je antimikrobna aktivnost protičnih jonskih tečnosti na bazi amina prema deset sojeva fungi: Trichoderma sp., Penicillium sp.(1-3), Cladoporium sp., Aspergillus sp. (1,2), A. flavus, F. graminearum i P. citrinium, osam sojeva bakterija: B. subtillis (6633), S. aureus (6538), E. faecalis (19433), K. rhizophila (9341), E. coli (11229), S. enteritidis (13076), P. mirabilis (12453), P. aeruginosa (15692) i dva soja kandida: C. albicans (ATCC 10231) i C. albicans (L) . Rezultati su pokazali da svih četrnaest jonskih tečnosti pokazuju antimikrobno delovanje. Za proučavane protične jonske tečnosti, antimikrobna aktivnost zavisi od dužine alkil lanca, pri tome pokazujući maksimalnu aktivnost sa anjonima koji sadrže 3 i 4 atoma ugljenika u nizu. Rezultati su pokazali da PILs pokazuju bolje antimikrobno dejstvo ako istovremeno sadrži i terminalno hlorovani C atom. Međutim, PILs pokazuju veću aktivnost ako je terminalni C atom monohalogeniran, jer monohalogenirani derivati poseduju veći afinitet za interakciju sa ćelijskom membranom. Najefikasnije PILs (ClA, 3-ClP, 4-ClB, Ac i For) su izabrane da se testiraju kao alternativni rastvarači umesto timola. Svih pet protičnih jonskih tečnosti uspešno je testirano kao zelena alternativa za uobičajne organske rastvarače koji se koriste za čišćenje i konzervaciju papirne površine. Značajna antimikrobna svojstva primećena u ovoj doktorskoj tezi sugeriraju da proučavane protične jonske tečnosti mogu imati potencijalnu primenu u radu sa papirnim atifaktima, kao i pri njihovom čišćenju i konzervaciji, zamenjujući na taj način primenu konvencionalnih rastvarača i organske supstance otrovne za ljude i životnu sredinu., In this doctoral thesis the 14 amine based protic ionic liquids were newly synthesized. The validity of all structures were checked and confirmed by NMR and IR spectroscopy. Densities of pure ionic liquids and their diluted aqueous solutions have been measured over the whole composition range at selected temperatures from (293.3 to 353.15) K for pure ionic liquids, and from (293.15 to 313.15) K for diluted aqueous solutions. Physico-chemical characterization was also performed measuring the viscosity and electrical conductivity of binary mixtures in the entire range of mole fractions and at different temperatures (T = (293.15 – 313.15) K). It was concluded that all investigated PILs have structure making tendency. Further, antimicrobial activity of amine based protic ionic liquids has been investigated using ten fungi strains: Trichoderma sp., Penicillium sp. (1-3), Cladoporium sp., Aspergillus sp. (1,2), A. flavus, F. graminearum i P. citrinium, eight ATCC bacterial strains: B. subtillis (6633), S. aureus (6538), E. faecalis (19433), K. rhizophila (9341), E. coli (11229), S. enteritidis (13076), P. mirabilis (12453), P. aeruginosa (15692) and two Candida strains: C. albicans (ATCC 10231) i C. albicans (L). The results indicated that all fourteen ionic liquids showed antimicrobial activity. For the studied PILs, the antimicrobial activity dependent on the alkyl chain length, showing maximal activity with anions containing 3 and 4 carbon atoms. The results revealed that the PILs show better antimicrobial activities if the longer alkyl chain is presented but in the same time contain chlorinated terminal C atom. However, PILs showed higer activity if the terminal C atom is monohalogenated, since the monohalogenated derivatives possess higher affinity to interact with cell membrane. The most effective PILs (ClA, 3-ClP, 4-ClB, Ac and For) were chosen to be tested as alternative solvents instead of thymol. All five PILs were successfully tested as the green alternatives to conventionally used organic solvents for paper cleaning and conservation. The significant antimicrobial properties observed in this doctoral thesis suggest that studied PILs may have potential applications in the paper art and artefact cleaning and conservation replacing thus, conventional solvents and organic substances that are toxic for humans and environment.

Thermally stable, flexible polymer gel electrolytes with high ionic conductivity are prepared by mixing the ionic liquid 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4mpyrTFSI), LiTFSI and poly(vinylidene difluoride‐co‐hexafluoropropylene (PVDF‐HFP). FT‐IR and Raman spectroscopy show that an amorphous film is obtained for high (60 %) C4mpyrTFSI contents. Thermogravimetric analysis (TGA) confirms that the polymer gels are stable below ∼300 °C in both nitrogen and air environments. Ionic conductivity of 1.9×10−3 S cm−2 at room temperature is achieved for the 60 % ionic liquid loaded gel. Germanium (Ge) anodes maintain a coulombic efficiency above 95 % after 90 cycles in potential cycling tests with the 60 % C4mpyrTFSI polymer gel., Flexible polymer gel electrolytes containing the ionic liquid C4mpyrTFSI were synthesized. Gels with the optimised ionic liquid content exhibited ionic conductivities comparable to organic solvent electrolytes. These gels enable stable lithium ion cycling in germanium.

Many studies have explored the pretreatment of lignocellulosic biomass based on oil palm empty fruit bunch (OPEFB) which is categorized as potential biomass waste for bioethanol production. Before proceeding further to obtain bioethanol, several steps such as pretreatment to increase organic constituents are needed. The ionic liquids (ILs) were commonly investigated by many researchers for lignocellulosic pretreatment because it is easy solubilization property, non-toxic, and not harmful impacts on the environment. Therefore in this study, the hypothesis and main objective were to observe the effectiveness of triethylammonium methanesulfonate ion liquid (TMS IL) in the OPEFB lignocellulose pretreatment process. Three variations were studied to obtain optimization of the pretreatment process, such as times duration, IL composition, and temperature. Based on these results, we observed the effectiveness of the time duration for OPEFB pretreatment of 20 hours. Furthermore, it was applied to determine the optimization of IL composition and temperature showing that using 91% (1:1:10) at 120°C for 20 hours has provided good performance for the OPEFB lignocellulose pretreatment process. TMS IL has exhibited the ability to reduce hemicellulose and lignin contents to 7.35% and 17.80%, whereas cellulose was increased by 54.24%. This has the opportunity to be projected to a larger scale for bioethanol production based on OPEFB lignocellulose.

Bi2S3 was dissolved in the presence of NaCl in the ionic liquid [BMIm]Cl ⋅ 4AlCl3 (BMIm=1‐n‐butyl‐3‐methylimidazolium) through annealing the mixture at 180 °C. Upon cooling to room temperature, orange, air‐sensitive crystals of Na(Bi7S8)[S(AlCl3)3]2[AlCl4]2 (1) precipitated. X‐ray diffraction on single‐crystals of 1 revealed a triclinic crystal structure that contains (Bi7S8)5+ spiro‐dicubanes, [S(AlCl3)3]2− tetrahedra triples, isolated [AlCl4]− tetrahedra, and sodium cations., In an ionothermal synthesis bismuth sulfide reacted to spiro‐dicubane cations (Bi7S8)5+, which crystallized in a complex structured salt. Diverse alkali metal cations were incorporated alongside these polycations, hinting at the existence of a structure family, despite stacking faults preventing a full structure elucidation of all compounds.

Deep eutectic solvents (DESs) comprise ChCl/urea, in combination with water, have been considered in removing acid gases (CO2 and H2S) from biogas. The evaluation of DES for biogas upgrading at relatively high pressure (i.e., >8.0 bar) has not been reported before. The aqueous DES performance has also not been analyzed compared to conventional amines-based solvent (MEA) and ionic liquid (IL). To the best of our knowledge, this is the first study that presents the integration of DES-based biogas upgrading with a mixed refrigerant liquefaction process to facilitate the safe and economical transportation of biomethane over long distances. The biogas considered in this study consisted of 60% CH4, 39% CO2, and 1% H2S. The aqueous ChCl/urea (70 wt%) results in biomethane with ≥99.0 wt% purity and ≥97.0 wt% recovery. Then, this biomethane was liquefied with ≥90% liquefaction rate. Based on the results obtained herein, overall capital, operating, and total annualized cost savings of 2.8%, 25.82%, and 14.26% were achieved using the 70% DES-based integrated process in comparison with the MEA-based integrated process. Whereas 1.41%, 16.85%, and 8.71% capital, operating, and total annualized costs could be saved in comparison with the IL (i.e., [Bmim][PF6])-based integrated process. It could be deduced that the overall cost of the biomethane value chain can be reduced using the proposed approach.

The metastable type‐II clathrate Na24‐δ Ge136 was obtained from Na12Ge17 by applying a two‐step procedure. At first, Na12Ge17 was reacted at 70 °C with a solution of benzophenone in the ionic liquid (IL) 1,3‐dibutyl‐2‐methylimidazolium‐bis(trifluoromethylsulfonyl) azanide. The IL was inert towards Na12Ge17, but capable of dissolving the sodium salts formed in the redox reaction. By annealing at 340 °C under an argon atmosphere, the X‐ray amorphous intermediate product was transformed to crystalline Na24‐δ Ge136 (δ≈2) and α‐Ge in an about 1 : 1 mass ratio. The product was characterized by X‐ray powder diffraction, chemical analysis, and 23Na solid‐state NMR spectroscopy. Metallic properties of Na24‐δ Ge136 were revealed by a significant Knight shift of the 23Na NMR signals and by a Pauli‐paramagnetic contribution to the magnetic susceptibility. At room temperature, Na24‐δ Ge136 slowly ages, with a tendency to volume decrease and sodium loss., The so far hardly accessible type‐II clathrate Na24‐δ Ge136 (δ≈2) was obtained in an about 1 : 1 mass ratio with α‐Ge from Na12Ge17 by redox reaction with benzophenone and subsequent heat treatment of the widely X‐ray amorphous intermediate. The phase is room‐temperature transient, diamagnetic and shows metallic properties as revealed by Knight‐shifted 23Na NMR signals and a Pauli‐paramagnetic contribution to the magnetic susceptibility.

We introduce a simple way to liquify rare earth metals (REM) by incorporating the corresponding cations, in particular Eu3+, La3+, and Y3+, into polyvalent ionic liquids (ILs). In contrast to conventional methods, this is achieved not by transforming them into anionic complexes, but by keeping them as bare cations and combining them with convenient, cheap and commercially available anions (A) in the form [REM3+][A − ]3. To do so, we follow the COncept of Melting Point Lowering due to EThoxylation (COMPLET) with alkyl polyethylene oxide carboxylates as anions. We provide basic properties, such as glass transition temperatures, viscosities, electrical conductivities, as well as water‐octanol partition constants P and show that these ILs have remarkably different properties, despite the similarity of their cations. In addition, we show that the ionic liquids possess interesting luminescent properties as non‐conventional fluorophores., Alkyl polyethylene oxide carboxylates allow for simple and safe synthesis of polyvalent ionic liquids with ‘naked’ rare earth metals without the need of additional complexation. The direct interactions between the ions produce strong ion‐specific properties despite the similarities between lanthanides. Proof of concept experiments highlight the feasibility of rare earth metal separation in liquid/liquid separation.

Aluminum electrodeposition can be carried out from several ionic liquid electrolyte formulations. Nevertheless, this plating process has not been industrialized so far because of the durability of the electrolytes and because the Al coatings obtained are non‐fully homogeneous in terms of coating morphology and thickness distribution. In this work we electrodeposited Al coatings from a 3‐butyl‐1‐ethylimidazolium tetrachloroaluminate electrolyte additivated with increasing concentrations of a new cost‐effective additive: light aromatic naphtha solvent. Firstly, electrolytes were characterized by cyclic voltammetry, where changes in the electrochemistry of the process were identified. Then, surface characterization showed that Al coatings morphology turned out to be smoother, more homogeneous and more compact with increasing additive concentration. Furthermore, the process was scaled up to flat plates of 18 cm2 area and also on 25 cm2 parts designed with straight corners to demonstrate both the optimization of the electrolytic bath performance and its throwing power enhancement.

The effective dehydration of glucose to 5‐hydroxymethylfurfural (HMF) has attracted increasing attention. Herein, a series of sulfonic‐acid‐functionalized ionic liquid (IL)–heteropolyacid (HPA) hybrid catalysts are proposed for the conversion of glucose to HMF. A maximum total yield of HMF and levoglucosan (LGA; ≈71 %) was achieved in the presence of pyrazine IL‐HPA hybrid catalyst [PzS]H2PW in THF/H2O–NaCl (v/v 5:1). The mechanism of glucose dehydration was studied by tailoring the Brønsted/Lewis acid sites of the hybrid catalysts and altering the solvent composition. It was found that water and heteropolyanions have a significant effect on the reaction kinetics. Heteropolyanions are able to stabilize the intermediates and promote the direct dehydration of glucose and intermediate LGA to HMF. A small amount of water could facilitate the conversion of glucose to LGA and suppress the dehydration of LGA to levoglucosenone. In addition, the synergetic effect of Brønsted/Lewis acid sites and a little water was conducive to accelerated proton transfer, which improved the yield of HMF from glucose dehydration.

An efficient ionic liquids (ILs) recycle technology will increase the economic viability of lignocellulosic biorefinery. The availability of recycling 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) for rice straw (RS) pretreatment was conducted. The kosmotropic salt K3 PO4 (TKP) solution was used as anti-solvent for cellulose precipitation and forming a three-phase system consisting of biomass, ILs-rich and salt-rich phases. The upper ILs phase and the bottom TKP phase were recycled without additional purification, which significantly simplifies the process for recovering ILs. Subsequently, the RS pretreated with multiple reusing ILs (RPRS) were investigated by components analysis, structure evolution, enzymatic hydrolysis and fermentation experiments. The results showed that unpurified reusing ILs led to further delignification and improvement of enzyme accessibility of the pretreated RS. The reducing sugar yield of RS pretreated with 8th reusing IL (8th RPRS) could still reach 98.9%, and the ethanol and succinic acid concentrations achieved 91.9 g/L and 29.3 g/L by simultaneous saccharification and co-fermentation (SScF). The present study demonstrated that the ILs recovered by phase-separation process could be used for RS pretreatment, and achieving high titer ethanol fermentation. This article is protected by copyright. All rights reserved.

The richness of high-value bio-compounds derived from microalgae has made microalgae a promising and sustainable source of useful product. The present work starts with a review on the usage of open pond and photobioreactor in culturing various microalgae strains, followed by an in-depth evaluation on the common harvesting techniques used to collect microalgae from culture medium. The harvesting methods discussed include filtration, centrifugation, flocculation, and flotation. Additionally, the advanced extraction technologies using ionic liquids as extractive solvents applied to extract high-value bio-compounds such as lipids, carbohydrates, proteins, and other bioactive compounds from microalgae biomass are summarized and discussed. However, more work needs to be done to fully utilize the potential of microalgae biomass for the application in large-scale production of biofuels, food additives, and nutritive supplements., Graphical Abstract

Bi2S3 was dissolved in the presence of either AuCl/PtCl2 or AgCl in the ionic liquids [BMIm]Cl ⋅ xAlCl3 (BMIm=1‐n‐butyl‐3‐methylimidazolium; x=4–4.3) through annealing the mixtures at 180 or 200 °C. Upon cooling to room temperature, orange, air‐sensitive crystals of [BMIm](Bi4S4)[AlCl4]5 (1) or Ag(Bi7S8)[S(AlCl3)3]2[AlCl4]2 (2) precipitated, respectively. 1 did not form in the absence of AuCl/PtCl2, suggesting an essential role of the metal cations. X‐ray diffraction on single‐crystals of 1 revealed a monoclinic crystal structure that contains (Bi4S4)4+ heterocubanes and [AlCl4]− tetrahedra as well as [BMIm]+ cations. The intercalation of the ionic liquid was confirmed via solid state NMR spectroscopy, revealing unusual coupling behavior. The crystal structure of 2 consists of (Bi7S8)5+ spiro‐dicubanes, [S(AlCl3)3]2− tetrahedra triples, isolated [AlCl4]− tetrahedra, and heavily disordered silver(I) cations. No cation ordering took place in 2 upon slow cooling to 100 K., Two new compounds containing sulfidobismuth cubane or spiro‐dicubane cations were obtained from metal assisted ionothermal syntheses. Fine‐tuning of the composition of the reaction mixture including the ionic liquid proved to be essential for successful syntheses.

This research presents the highly regioselective syntheses of 1,2‐dicarboxylated cyclopentadienide salts [Cat]2[C5H3(CO2)2H] by reaction of a variety of organic cation methylcarbonate salts [Cat]OCO2Me (Cat=NR4 +, PR4 +, Im+) with cyclopentadiene (CpH) or by simply reacting organic cation cyclopentadienides Cat[Cp] (Cat=NR4 +, PR4 +, Im+) with CO2. One characteristic feature of these dianionic ligands is the acidic proton delocalized in an intramolecular hydrogen bridge (IHB) between the two carboxyl groups, as studied by 1H NMR spectroscopy and XRD analyses. The reaction cannot be stopped after the first carboxylation. Therefore, we propose a Kolbe‐Schmitt phenol‐carboxylation related mechanism where the acidic proton of the monocarboxylic acid intermediate plays an ortho‐directing and CO2 activating role for the second kinetically accelerated CO2 addition step exclusively in ortho position. The same and related thiocarboxylates [Cat]2[C5H3(COS)2H] are obtained by reaction of COS with Cat[Cp] (Cat=NR4 +, PR4 +, Im+). A preliminary study on [Cat]2[C5H3(CO2)2H] reveals, that its soft and hard coordination sites can selectively be addressed by soft Lewis acids (Mo0, Ru2+) and hard Lewis acids (Al3+, La3+)., A highly regioselective synthesis of 1,2‐dicarboxylated and ‐dithiocarboxylated cyclopentadienide salts [Cat]2[C5H3(CO2)2H] by reaction of organic cation methylcarbonate salts Cat[OCO2Me] (Cat=DMP+, NMe4 +, EMMIm+) with cyclopentadiene or by reaction of CO2/COS with Cat[Cp] (Cat=DMP+, NMe4 +, PPh4 +) was developed. First insight into their coordination chemistry reveals ambident ligand behaviour following Pearsons acid‐base concept. In some reactions with metal Lewis acids, a slow decarboxylation of the [C5H3(CO2)2H] ligand was observed. The mechanism is discussed.

The standard methodology for the synthesis of oligonucleotides is the solid-phase method. Here, we report the first case of mechanochemistry being directly applied to the synthesis of a dinucleotide on a soluble support. While mechanochemistry eliminates the need to solubilise a supported oligomer in solution phase for phosphoramidite coupling, the support still confers the benefit of being able to purify the product by precipitation, or by simple liquid-liquid extractions as needed. Furthermore, this study also explores the use of mechanochemistry in the initial functionalisation of the ionic liquid support with a nucleoside monomer.

Metalation of the anions in the ionic liquids DMPyr[SH] and DMPyr[SeH] (DMPyr=1,1‐dimethylpyrrolidinium) by trimethylgallium and trimethylindium is investigated. The reaction proceeds via pre‐coordination of [EH]−, methane elimination and formation of an unprecedented series of chalcogenido metalates DMPyr2[Me2M(μ2−E)]2 (M=Ga, In; E=S, Se). These show the presences of dinuclear dianions with four‐membered ring structures displaying highly nucleophilic bridging chalcogenide ligands in their crystallographically determined molecular structures. Some representative reactions of these building blocks with amphoteric electrophiles were studied: Addition of two equivalents of E(SiMe3)2 (E=S, Se) to the indates DMPyr2[Me2In(μ 2−S)]2 and DMPyr2[Me2In(μ2−Se)]2 leads to a cleavage of the ring, E silylation and formation of mononuclear, monoanionic indates DMPyr[Me2In(SSiMe3)2], DMPyr[Me2In(SeSiMe3)2], and even a mixed sulfido‐selenido dimethylindate DMPyr[Me2In(SSiMe3)(SeSiMe3)]. Reaction of DMPyr2[Me2In(μ2−S)]2 with two equivalents of Lewis acid Me3In leads to charge delocalization, ring expansion and formation of six‐membered ring DMPyr3[Me2In(μ 2−S−InMe3)]3. The latter is a key intermediate in the formation of dianionic sulfidoindate DMPyr2[(Me2In)6(μ 3−S)4] displaying an unusual inverse heteroadamantane cage structure with four capping sulfido ligands., Thermodynamics in action! Condensation of Me3Ga and Me3In with anions [EH]− (E=S, Se) to four‐membered rings, their cleavage or expansion and condensation to a cluster with inverse adamantane structure is driven by methane elimination, charge delocalization and dissociation.

Processes that can convert lignocellulosic biomass into biofuels and chemicals are particularly attractive considering renewability and minimal environmental impact. Ionic liquids (ILs) have been used as novel solvents in the process development in that they can effectively deconstruct recalcitrant lignocellulosic biomass for high sugar yield and lignin recovery. From cellulose-dissolving ILs to choline-based and protic acidic ILs, extensive research in this field has been done, driven by the promising future of IL pretreatment. Meanwhile, shortcomings and technological hurdles are ascertained during research and developments. It is necessary to present a general overview of recent developments and challenges in this field. In this review paper, three aspects of advances in IL pretreatment are critically analyzed: biocompatible ILs, protic acidic ILs and combinatory pretreatments.

The ionic liquid (IL) trihalogen monoanions [N2221][X3]− and [N2221][XY2]− ([N2221]+=triethylmethylammonium, X=Cl, Br, I, Y=Cl, Br) were investigated electrochemically via temperature dependent conductance and cyclic voltammetry (CV) measurements. The polyhalogen monoanions were measured both as neat salts and as double salts in 1‐butyl‐1‐methyl‐pyrrolidinium trifluoromethane‐sulfonate ([BMP][OTf], [X3]−/[XY2]− 0.5 M). Lighter IL trihalogen monoanions displayed higher conductivities than their heavier homologues, with [Cl3]− being 1.1 and 3.7 times greater than [Br3]− and [I3]−, respectively. The addition of [BMP][OTf] reduced the conductivity significantly. Within the group of polyhalogen monoanions, the oxidation potential develops in the series [Cl3]−>[BrCl2]−>[Br3]−>[IBr2]−>[ICl2]−>[I3]−. The redox potential of the interhalogen monoanions was found to be primarily determined by the central halogen, I in [ICl2]− and [IBr2]− , and Br in [BrCl2]−. Additionally, tetrafluorobromate(III) ([N2221]+[BrF4]−) was analyzed via CV in MeCN at 0 °C, yielding a single reversible redox process ([BrF2]−/[BrF4]−)., The trihalogen monoanions ionic liquids [NEt3Me]+[Cl3]−/[Br3]−/[I3]−/[BrCl2]−/[ICl2]−/[IBr2]− and the tetrafluorobromate(III) monoanion [N2221][BrF4] in acetonitrile were electrochemically analyzed via temperature dependent conductance and cyclic voltammetry measurements. The electrochemical redox potentials were determined of neat salts and in a mixture of pyrrolidinium based ionic liquid, with [Cl3]− and [BrF4]− being the strongest oxidizing agents.

Substituted imidazolium ionic liquids (ILs) were investigated for their reactivity towards Na12Ge17 as a model system containing redox‐sensitive Zintl cluster anions. The ILs proved widely inert for imidazolium cations with a 1,2,3‐trisubstitution at least by alkyl groups, and for the anion bis(trifluoromethylsulfonyl)azanide (TFSI). A minute conversion of Na12Ge17 observed on long‐time contact with such ILs was not caused by dissolution of the salt‐like compound, and did thus not provide dissolved Ge clusters. Rather, a cation exchange led to the transfer of Na+ ions into solution. In contrast, by using benzophenone as an oxidizer, heterogeneous redox reactions of Na12Ge17 were initiated, transferring a considerable part of Na+ into solution. At optimized conditions, an X‐ray amorphous product NaGe6.25 was obtained, which was thermally convertible to the crystalline type‐II clathrate Na24–δGe136 with almost completely Na‐filled polyhedral cages, and α‐Ge. The presented method thus provides unexpected access to Na24–δGe136 in bulk quantities., High‐purity 1,2,3‐trisubstituted imidazolium [TFSI] ionic liquids were prepared and found inert towards the redox‐sensitive Na12Ge17, making them suitable media for heterogeneous redox reactions. By admixture of benzophenone, Na12Ge17 was oxidized to an X‐ray amorphous product, which proved valuable as a precursor for a thermal conversion to the difficult to access type‐II clathrate Na24–δGe136 with almost completely Na‐filled polyhedral cages.

Based on the strand‐like coordination polymer (CP) type 1 ∞[Ln(BSB)3(py)2], [BSB]−=bis‐salicylatoborate anion, mixed Eu/Tb‐containing compounds of the constitution 1 ∞[EuxTb1−x(BSB)3(py)2] were synthesised ionothermally for a phase width of (x=0.25–0.75) and characterized regarding structure and optical properties. Previously, known only for other lanthanides, the mixed 1D−Eu/Tb‐CPs show excellent options for statistic replacement of the Ln‐cations during synthesis yielding solid solutions. The products are highly luminescent, with the chromaticity being a direct function of the amount of the respective Ln‐ions. Corresponding to an overall addition of emission intensities, the green Tb3+ emission and the red Eu3+ emission allow for a chromaticity control that also includes yellow emission. Control of the luminescence colour renders them suitable examples of the versatility of statistic replacement of metal ions in coordination chemistry. In addition, crystallization of [EMIm]2[YCl5(py)] illuminates possible other products of the ionothermal reactions of [EMIm][BSB] with LnCl3 constituted by components not being part of the main CPs., Luminescence chromaticity tuning between green, yellow and red was achieved by statistic replacement of Eu3+ and Tb3+ in the coordination polymers 1 ∞[EuxTb1−x(BSB)3(py)2], (x=0.25–0.75), containing the bis‐salicylatoborate anion.