Trihexyl Tetradecyl Phosphonium Research Articles

The role of ionic liquid additives in enhancing the tribological performance of plastic-derived oils

Improper disposal of waste plastic contributes significantly to environmental pollution. A promising solution to address this issue involves converting such plastics into valuable lubricating oils. This study investigated the tribological performance of both an aromatic-lean industrial plastic oil (PO) and aromatic-rich lab-scale plastic oils (LPO) using a ball-on-disk setup. The results revealed that PO exhibited considerably higher coefficients of friction (COF) and specific wear rates compared to LPO. To enhance the lubrication performance, a bio-based ionic liquid (IL: trihexyltetradecyl phosphonium saccharinate) with an unsaturated anion was incorporated. The COF and wear rates were further reduced with an IL blend in both PO and LPO. The IL additive promoted increased film thickness, beneficial micelle formation, facilitated adsorption film formation, and provided a phosphorus-rich tribofilm. These mechanisms collectively contributed to the notable improvement in tribological performance. Overall, this research demonstrates the potential of IL additives to enhance the tribological performance of both PO and LPO, thereby mitigating waste plastic pollution, and fostering a sustainable future.

Enhanced furfural extraction using neoteric hydrophobic solvents for sustainable biomass recovery and bioenergy applications

The recovery of furfural from hemicellulosic biowastes is important for developing sustainable and renewable energy alternatives to fossil fuels. However, current methods are inefficient and environmentally questionable. To address this issue, this study introduces neoteric hydrophobic solvents, specifically deep eutectic solvents (DESs) and ionic liquids (ILs). Of the 32 solvents tested, thymol:decanoic acid 1:1 (Thy:DecA) DES and trihexyltetradecyl phosphonium bis(trifluoro methylsulfonyl) imide [P14,6,6,6][NTf2] IL were the most effective, with extraction efficiencies of 94.1% and 97.1%, respectively. These solvents outperformed the reference solvent toluene, with an efficiency of 81.2%, while also showing favorable characteristics in multiple investigated criterions. For the first time, excellent performance stability was demonstrated under various operational conditions and reusability over multiple extraction and regeneration cycles. Furthermore, to provide insights into the molecular mechanisms of extraction, computational quantum chemistry modeling was employed, which showed a strong agreement with the experimental results. The development of these new neoteric solvents for furfural recovery from biowaste offers a highly effective, sustainable, and eco-friendly alternative to traditional solvents, representing a significant breakthrough in the field of renewable bioenergy production and sustainable materials recovery.

Extractive desulfurization of crude petroleum oil and liquid fuels using trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate ionic liquid

Abstract Increasing environmental concerns have led to the development of alternative methods for the desulfurization of petroleum crude oil and liquid fuels. Phosphonium-based ionic liquids (PILs) have recently demonstrated promising potential for effective extractive desulfurization (EDS). The present study focuses on the synthesis and application of trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate [THTDP][D2EHP] for EDS of synthetic model fuels and real crude oils. The molecular confirmation and thermal stability of [THTDP][D2EHP] were investigated using FTIR and TGA analyses. In addition, the conductivity, solubility, and viscosity of the synthesized ionic liquid (IL) were analyzed. The impact of reaction time, temperature, and sulfur compounds, such as thiophene, benzothiophene, and dibenzothiophene (DBT), on the desulfurization efficiency from synthetic fuels was also investigated. The results indicated up to 63 and 57 % sulfur removal from DBT-based model fuels and Iranian crude oil, respectively. The optimum extraction conditions were found as 1:1 IL/fuel mass ratio, 35 °C, and 30 min. The findings of this study provide valuable insights into the synthesis and utilization of PILs as promising solvents for extractive desulfurization of crude oil and liquid fuels.

Well-Dispersed Graphene Enhanced Lithium Complex Grease Toward High-Efficient Lubrication

Graphene as a lubricating additive holds great potential for industrial lubrication. However, its poor dispersity and compatibility with base oils and grease hinder maximizing performance. Here, the influence of graphene dispersion on the thickening effect and lubrication function is considered. A well-dispersed lubricant additive was obtained via trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate modified graphene ([P66614][DEHP]-G). Then lithium complex grease was prepared by saponification with 12-OH stearic acid, sebacic acid, and lithium hydroxide, using polyalphaolefin (PAO20) as base oil and the modified-graphene as lubricating additive, with the original graphene as a comparison. The physicochemical properties and lubrication performance of the as-prepared greases were evaluated in detail. The results show that the as-prepared greases have high dropping point and colloidal stability. Furthermore, modified-graphene lithium complex grease offered the best friction reduction and anti-wear abilities, manifesting the reduction of friction coefficient and wear volume up to 18.84% and 67.34%, respectively. With base oil overflow and afflux, well-dispersed [P66614][DEHP]-G was readily adsorbed to the worn surfaces, resulting in the formation of a continuous and dense graphene deposition film. The synergy of deposited graphene-film, spilled oil, and adhesive grease greatly improves the lubrication function of grease. This research paves the way for modulating high-performance lithium complex grease to reduce the friction and wear of movable machinery.

Structure activity relationship of novel antibacterial phosphonium ionic liquids/organic salts in dispersions and on films: Potential antifouling coating materials

The worldwide increasing threat from drug resistant strains, urge continuous development of novel and effective antibacterial agents to minimize nosocomial infections and associated deaths. In this direction ionic liquids (ILs) or analogous organic salts (OS) have exhibited promising potential due to their ease of designability and tunable properties. Herein, nine structurally different phosphonium based ionic liquids (ILs)/Organic Salts (OS) were developed and investigated for their structural effect on antibacterial activity in dispersions and surface coatings. This study reveals that the structural effect on bactericidal property is reversed in coatings compared to dispersions. The pure aryl phosphonium viz. (tetraphenyl phosphonium [TTP]+) cation based IL of ampicillin (Amp−) demonstrate highest bactericidal effect in dispersion compared to alkyl aryl phosphonium (ethyltriphenyl phosphonium)-ampicillin IL and the least activity was observed for pure tetra alkyl phosphonium (trihexyltetradecyl phosphonium)-ampicillin ILs. However, on coatings the activity was reversed. It is observed that optimum hydrophilic-lipophilic balance of ILs/OS dominated the bactericidal effect in dispersions whereas on coating the most lipophiphilic IL/OS demonstrated highest activity. In dispersions the bactericidal effect is a combined property of the cation and the anion while on glass coatings primarily cationic part dominate the bactericidal effect as the hydrophilic ampicillin anion is attached to the glass surface. SwissADME based skin permeation study indicate good potential of the [TPP][Amp] IL as topical antibiotics with a log Kp of 6.91 cm/s and Log P of 3.62. Thus, the present study reveals the structural effect on antibacterial properties of ILs/OS are system dependent as implied from the investigation of some phosphonium ILs/OS and provides useful information for developing washable transparent antifouling coatings.

From tetraalkylphosphonium ionic liquids to phosphonium ylides: How the ionic sizes influence carbon dioxide capture?

Carbon dioxide (CO2) capture via the phosphonium ylide mechanism represents an interesting alternative to alkylamine-based carboxamidation. The tertiary cation-based CO2 sorption supplements the nitrogen-containing anion-based CO2 sorption which ultimately results in very competitive aggregate capacities of such ionic compounds. In the present work, we reveal the impact of the cation and anion sizes on the deprotonation and subsequent carboxylation of the α-methylene carbon of the phosphonium-based cations. In particular, we computationally investigate the role of the alkyl chains and rationalize the previously published experimental results. Since the anions strongly influence the kinetics and thermodynamics of the processes involving their counterions, we herein supplemented the triethyl-butyl phosphonium [P2224] and trihexyl-tetradecyl phosphonium [P66614] cations in our models with the benzimidazolide [BENZIM], and 2–methylthio-benzimidazolide aprotic anions [2MTBENZIM]. By having determined the energetic effects, activation barriers, and steric hindrances faced by the above-referenced processes through potential energy surface scans empowered by electronic-structure simulations, we formulated lucid guidelines for the molecular design of the CO2 scavengers of this class. We found that the alkyl chain length plays a marginal role in the reaction profiles for CO2 capture. In turn, an identity of the anion was found to impact the phosphonium ylide formation stages by 20 % by adjusting local intermolecular interactions. By analyzing molecular geometries in their initial, transition, and product states along with the atomic hydrophobicities, we explained the stepwise energetics of the CO2 chemisorption by the phosphonium-based sorbents of complicated structure and two-stage performance. As we did not detect differences of commensurate magnitude between the [P2224] and [P66614] cations paired with both [BENZIM] and [2MTBENZIM], we linked a somewhat deteriorated experimentally detected performance (∼10 %) of [P66614] to differing shear viscosities and, thus, slowed down the diffusion of CO2. For the sake of practical applications, the [P2224]-based ionic liquids look preferable as long as their physicochemical properties meet the criteria of a specific technological task and the costs of their synthesis are comparable to those of the [P66614]-based ones.

Ionic Liquids as Biocompatible Antibacterial Agents: A Case Study on Structure-Related Bioactivity on Escherichia coli.

The potential of ionic liquids (ILs) to be used as antimicrobial agents for biomedical applications has been hindered by the fact that most of them are cytotoxic toward mammalian cells. Understanding the mechanism of bacterial and mammalian cellular damage of ILs is key to their safety design. In this work, we evaluate the antimicrobial activity and mode of action of several ILs with varying anions and cations toward the clinically relevant Gram-negative Escherichia coli. Langmuir monolayer technique was used to evaluate if the IL's mode of action was related to the bacterial cell membrane interaction for an effective E. coli killing. 1-Decyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [DMIM][TFSI] and trihexyltetradecyl phosphonium bis(trifluoromethylsulfonyl) imide [P6,6,6,14][TFSI] were surface-active and induced bacterial cell lysis, through a membrane-disruption phenomenon on bacteria, in a mechanism that was clearly related to the long alkyl chains of the cation. 1-Ethyl-3-methylimidazolium hydrogen sulfate [EMIM][HSO4] was highly antimicrobial toward E. coli and found suitable for biological applications since it was harmless to mammalian cells at most of the tested concentrations. The results suggest that the imidazolium cation of the ILs is mostly responsible not only for their antimicrobial activity but also for their cytotoxicity, and the inclusion of different anions may tailor the ILs' biocompatibility without losing the capacity to kill bacteria, as is the case of [EMIM][HSO4]. Importantly, this IL was found to be highly antimicrobial even when incorporated in a polymeric matrix.

Tribological performance of phosphonium-based halogen-free ionic liquids as lubricant additives

In recent years, ionic liquids have shown great potential as an additive in lubricants. However, most of the explored ionic liquids for machining applications contain halogen-based anions, which are sensitive to moisture and have a tendency to produce harmful halogen acids (HX) after reacting with water/moisture. These acids are harmful to the environment and can corrode the working surfaces. This study investigates the effectiveness of halogen-free ionic liquids as potential additives to vegetable oil (canola oil). Two halogen-based ionic liquids (1-methyl 3-butylimidazolium tetrafluoroborate [BMIM BF4] and 1-methyl 3-butylimidazolium hexafluorophosphate [BMIM PF6]) and one halogen-free ionic liquids (trihexyl tetradecyl phosphonium bis (24,4-trimethylpentyl) phosphinate P6,6,6,14 [i(C8)2PO2]) were blended individually with canola oil. The percentage ratio of ionic liquid to canola oil is 1:99. Dynamic viscosity and contact angles of different lubricants were measured. Sliding tests were conducted in various conditions; dry, canola oil, and three different blends of ionic liquid with canola oil. Further, to connect tool-chip tribology with machining, turning experiments were carried out under similar lubricating conditions. Results show that the sliding friction, pin surface temperature, and wear were reduced by 48.1%, 44%, and 69.6%, respectively, due to better lubricating ability and spreading tendency of halogen-free ionic liquid blended with canola oil. The microscopic analyses of pin surfaces and the morphology of counter disc surfaces further supported better lubrication between the sliding pair. For P6,6,6,14 [i(C8)2PO2] ionic liquid blended with canola oil, the average cutting temperature and machined workpiece surface roughness reduces by 43.6% and 62.4% compared to dry machining.

Application of bifunctional ionic liquids for extraction and separation of Eu3+ from chloride medium

The extraction of Eu3+ from chloride medium using bifunctional ionic liquid extractants (Bif-ILEs) tri-n-octylmethyl ammonium bis(2-ethyl hexyl) phosphate ([A336][D2EHP]) and trihexyltetradecyl phosphonium bis(2-ethylhexyl) phosphate ([P66614][D2EHP]) in kerosene was studied to develop environmentally friendly extraction process. The extraction behavior of Eu3+ was examined by varying key process parameters. The extraction behavior indicates that ammonium-based ionic liquid [A336][D2EHP] shows better extraction efficiency of Eu3+ than that of phosphonium-based ionic liquid [P66614][D2EHP]. Quantitative extraction of Eu3+ is obtained with 0.05 mol/L [A336][D2EHP], whereas, 0.1 mol/L of [P66614][D2EHP] is required to achieve the same extraction rate of Eu3+. The extraction process is endothermic with respect to [A336][D2EHP]. Stripping experiments indicate that 100% of Eu3+ can be back extracted from both the loaded ionic liquids using 20 vol.% HNO3. The highest separation factor (βY/Eu) of 653.59 is reported at pH of 3.2, and the separation factor of Eu3+ over La3+ is 30.6 at the same pH. From the leach liquors of waste tube light powder, 99.98% of Eu and 99.99% Y are recovered using 0.2 mol/L [A336][D2EHP] in 2-stage cross current extraction with aqueous to organcic ratio (O/A) of 1:1 and 1:2.

Pressure-induced liquid-liquid transition in a family of ionic materials

Liquid−liquid transition (LLT) between two disordered phases of single-component material remains one of the most intriguing physical phenomena. Here, we report a first-order LLT in a series of ionic liquids containing trihexyl(tetradecyl)phosphonium cation [P666,14]+ and anions of different sizes and shapes, providing an insight into the structure-property relationships governing LLT. In addition to calorimetric proof of LLT, we report that ion dynamics exhibit anomalous behavior during the LLT, i.e., the conductivity relaxation times (τσ) are dramatically elongated, and their distribution becomes broader. This peculiar behavior is induced by isobaric cooling and isothermal compression, with the τσ(TLL,PLL) constant for a given system. The latter observation proves that LLT, in analogy to liquid-glass transition, has an isochronal character. Finally, the magnitude of discontinuity in a specific volume at LLT was estimated using the Clausius-Clapeyron equation.

Trihexyl tetradecyl phosphonium bromide as an effective catalyst/extractant in ultrasound-assisted extractive/oxidative desulfurization.

Phosphonium-based ionic liquid (PIL) has been used as a catalyst and extractant. Here, the PIL, trihexyl tetradecyl phosphonium bromide ([THTDP]Br) was utilized for the S-removal of model oil (MO) and acted as the reaction-induced self-separation catalyst. The influence of oxidant to sulfur molar ratio (n(O/S)), mass ratio of model oil to ionic liquid (m(MO/IL)), sonication time, and temperature was observed to investigate the optimal conditions for the ultrasound-assisted extractive/oxidative desulfurization (UEODS) catalyzed by [THTDP]Br. A kinetic study was performed, and the reaction rate constant and half-life were calculated as the oxidation reaction was following pseudo-first-order reaction kinetics. Moreover, the oxidation reactivity and selectivity of various sulfur substrates were in the following order: DBT > BT > TH > 3-MT. The DBT removal with various initial S-content was observed to be constant, which makes it feasible for practical application. The interaction energy between [THTDP]Br and S-compounds was examined using Density Functional Theory. The sulfur removal of base oil (BO) was also examined using various desulfurization systems at DBT optimized conditions. The highest desulfurization efficiency of BO was obtained during the UEODS process, which made it industrially feasible. [THTDP]Br was regenerated and recycled six times with a slight variation in efficiency.

Application of response surface methodology with central composite design to evaluate the extraction of U(VI) into ionic liquids

Application of response surface methodology with central composite design to evaluate Uranium (VI) extraction from acidic medium by tri-n-butyl phosphate (TBP) solution into Ionic liquids has been studied. At low acidic solution i.e. at 0.01 M HNO3 the enhancement in distribution ratio DU in [EMIM][TF2N], [BMIM][TF2N], [Trihexyl tetradecyl phosphonium][TF2N] compared to dodecane is ∼ 347, 260 and 82 times and to TBP it is ∼ 300, 225 and 70 times respectively. Percent extraction (% E) of uranium into [EMIM][TF2N] is found to be highest 93% compared to other ionic liquids. The RSM with two-level-two-full factorial CCD was employed to predict the statistical model which relates the TBP composition and pH to the DU with (R2 = 98.6%). The model equation is tested for its suitability by analysis of variance (ANOVA) and it is found to be in good agreement with the experimental data.

Ultrasound-assisted extractive/oxidative desulfurization of oil using environmentally benign trihexyl tetradecyl phosphonium chloride

A phosphonium-based ionic liquid (PIL) trihexyl tetradecyl phosphonium chloride ([THTDP]Cl) was applied as an effective catalyst/extractant for the desulfurization of model oil (MO) as well as base oil. In the ultrasound-assisted extractive/oxidative desulfurization (UEODS) process, a liquid–liquid catalytic oxidative desulfurization system containing MO/base oil, hydrogen peroxide, and PIL was observed at 30 °C and maximum sulfur removal of 98.67% was obtained. After completion of the reaction, PIL was separated from MO. The PIL was then regenerated and recycled 5 times without a significant decrease in efficiency. The influence of UAODS of MO containing dibenzothiophene (DBT), benzothiophene (BT), thiophene (T), and 3-methyl thiophene (3-MT) was also observed, which shows fast oxidative desulfurization capability under ultrasound irradiation. The oxidation reactivity of sulfur compounds follows the order of DBT > BT > TH > 3-MT at the DBT optimized conditions. The quantity of PIL, H2O2/DBT mole ratio, oxidation temperature, and time all played significant roles in sulfur removal, which were also analyzed in detail to optimize the reaction conditions during UEODS. The density functional theory study was carried out to understand the exact mechanism responsible for the effective interaction between PIL and sulfur compounds. The desulfurization of base oil was also carried out to check the feasibility of the UEODS process and achieved 74.98% desulfurization efficiency. These results proved the efficacy of the UEODS process for industrial application.

Characterization of membrane wetting phenomenon by ionic liquid via ultrasonic time-domain reflectometry (UTDR)

Ionic liquids (ILs) are becoming attractive solvents or catalysts in many industries, thus energy-efficient membrane-based technologies for the purification and concentration of ILs are gaining attention. Membrane wetting by ILs is recognised as the major challenge in membrane processes, but limited information is available. In this study, the dynamics of wetting of commercial hydrophobic polytetrafluoroethylene (PTFE) membranes by a water-immiscible IL, trihexyl(tetradecyl)phosphonium (THTDP), was characterized by an online and non-destructive technique – ultrasonic time-domain reflectometry (UTDR). In the UTDR analysis, information such as resistance of membrane to IL penetration, duration and rate of wetting process can be deduced from the changes in arrival time and amplitude of reflected peak from the IL/pore-air interface, i.e., pores in pristine hydrophobic membrane are completely-filled with air until IL penetration that displaces the pore-air. The UTDR analysis was further supported by offline and destructive methods typically used to characterize membrane such as Fourier-transform infrared spectroscopy (FTIR), contact angle (CA), liquid entry pressure (LEP) and field emission scanning electron microscopy (FESEM). Through the abovementioned analyses, it was concluded that the commercial hydrophobic PTFE membranes exhibited poor anti-wetting properties against concentrated THTDP IL due to chemical affinity between IL and membrane.

Negative-ion field desorption revitalized by using liquid injection field desorption/ionization-mass spectrometry on recent instrumentation

Field ionization (FI), field desorption (FD), and liquid injection field desorption/ionization (LIFDI) provide soft positive ionization of gaseous (FI) or condensed phase analytes (FD and LIFDI). In contrast to the well-established positive-ion mode, negative-ion FI or FD have remained rare exceptions. LIFDI provides sample deposition under inert conditions, i.e., the exclusion of atmospheric oxygen and water. Thus, negative-ion LIFDI could potentially be applied to highly sensitive anionic compounds like catalytically active transition metal complexes. This work explores the potential of negative-ion mode using modern mass spectrometers in combination with an LIFDI source and presents first results of the application of negative-ion LIFDI-MS. Experiments were performed on two orthogonal-acceleration time-of-flight (oaTOF) instruments, a JEOL AccuTOF GCx and a Waters Micromass Q-TOF Premier equipped with LIFDI sources from Linden CMS. The examples presented include four ionic liquids (ILs), i.e., N-butyl-3-methylpyridinium dicyanamide, 1-butyl-3-methylimidazolium tricyanomethide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate), 3-(trifluoromethyl)-phenol, dichloromethane, iodine, polyethylene glycol diacid, perfluorononanoic acid, anionic surfactants, a tetraphosphazene silanol-silanolate, and two bis(catecholato)silanes. Volatile samples were delivered as vapors via the sample transfer capillary of the LIFDI probe or via a reservoir inlet. Condensed phase samples were applied to the emitter as dilute solutions via the sample transfer capillary. The compounds either yielded ions corresponding to their intact anions, A−, or the [M–H]− species formed upon deprotonation. This study describes the instrumental setups and the operational parameters for robust operation along with a discussion of the negative-ion LIFDI spectra of a variety of compounds.

Design, development and mechanistic insights into the enhanced antibacterial activity of mono and bis-phosphonium fluoresceinate ionic liquids

Configuring ionic liquids (ILs) to generate synergy or to deliver multiple pharmaceutically active ingredients through a single compound is an emerging area in future medicine where phosphonium ionic liquids (PILs) exhibit potential as antibacterial drugs. Herein, we report the strategic development of two purely ionic mono and bis-PILs based on trihexyltetradecyl phosphonium ([TTP]+) contributing as the cation coupled with monoprotonated fluorescein ([HFl]-) and dianionic fluorescein ([Fl2-]) anions through metathesis reaction. In spite of negligible bactericidal effect of [Fl]2-, the [HFl]- and [Fl2- salts exhibit enhanced and selective bactericidal activity at drastically reduced concentrations. [TTP][HFl] exhibits bactericidal effect at 2 times lower concentration against E. coli and [TTP]2[Fl] at 10 times lower concentrations against S. aureus with respect to the precursor [TTP][Cl]. Docking studies of [TTP][HFl] and [TTP]2[Fl] as well as the precursors with two modelled bacterial cell wall fragments and three RNAs indicate direct correlation between best binding pose and experimentally obtained minimum bactericidal concentrations (MBC). The study suggests the inhibition of peptidoglycan maturation through linkage between phenolate of Fl unit and the D-Ala-D-Ala group of the peptide chain in the cell wall fragment as well as inhibition of RNA/DNA synthesis as probable mechanisms of bacterial cell death. This multistaged cell death mechanism explains the appearance of unexpectedly improved antibacterial activity and selectivity in the mono and bis- phosphonium fluorescein salts. Thus, the results recommend strong potential of the studied PILs to be used as new series of broad spectrum antibacterial agents with reduced risk for development of drug resistant strains.

Separation of vanillin by perstraction using hydrophobic ionic liquids as extractant phase: Analysis of mass transfer and screening of ILs via COSMO-RS

This paper presents an experimental and theoretical study for a perstraction system to recover diluted vanillin from aqueous solutions using an organophilic and hydrophobic membrane of polydimethylsiloxane (PDMS), and the hydrophobic ionic liquids (ILs) 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([bmim][Tf2N]), 1-octyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([omim][Tf2N]) and trihexyl tetradecyl phosphonium cyanamide ([P6,6,6,14][DCA]) as the extractant phase. The proposed mass transfer model was established as suitable for describing the extraction of vanillin from the aqueous phase in the perstraction system using ILs. According to this model, it was determined that the main mass transfer resistances were offered by the PDMS membrane, followed by the IL. [P6,6,6,14][DCA] experimentally showed a 13% increase in the transmembrane flux in comparison with the [Tf2N] anion based ILs, but also showed higher water transmembrane flux. In this regard, [omim][Tf2N] was found to exhibit better vanillin/water selectivity. The perstraction system gives better transmembrane fluxes than the data reported in the literature for vanillin extraction using pervaporation system. On the other hand, according to the screening in COSMO-RS, the combination of the anions DCA, SCN, TCC, Otf, PFBS, Tf2N, Pf2N y PF6 with pyrrolidinium, piperidinium and phosphonium base cations, are suitable to increase the performance of vanillin extraction.

The Power of Ionic Liquids: Crystal Facet Engineering of SrTiO3Nanoparticles for Tailored Photocatalytic Applications

AbstractSonochemical synthesis of nano‐sized SrTiO3carried out at close to room temperature, in ionic liquids (ILs) allows the tuning of particle size and particle morphology, that is, tracht and habitus, as well as particle aggregation via the choice of the ionic liquids (ILs) as the reaction medium. The nanoparticles demonstrate high performance for photocatalytic water splitting and photodecomposition of organic material. To this end bis(trifluoromethanesulfonyl)amide ([Tf2N]−)‐based ILs with cations of different properties with respect to specific interactions with the target material are investigated. Isolated, 15±1 nm sized nano‐spheres of SrTiO3are observed to form in [C3mimOH][Tf2N] ([C3mimOH]+ =1‐(3‐hydroxypropyl)‐3‐methylimidazolium). Aggregation of small sized nanoparticles are observed to around 250±100 nm large cube‐like formations in [C4mim][Tf2N] ([C4mim]+ =1‐butyl‐3‐methylimidazolium), raspberry‐like in [C4Py][Tf2N] ([C4Py]+butylpyridinium), and ball‐like in [P66614][Tf2N] ([P66614]+tetradecyltrihexyl phosphonium). Importantly, the different materials show different performance as photocatalysts. SrTiO3prepared in [C4mim][Tf2N] shows the highest photocatalytic activity for H2evolution (1115.4µmol h−1) when using 0.025 wt% Rh as the co‐catalyst, whereas the material prepared in [C3mimOH][Tf2N] shows the highest activity for the photocatalytic degradation of methylene blue (88%) under UV irradiation. The different photocatalytic activities can be correlated with the different crystal surface facets expressed in the respective nanosized SrTiO3material, {110} for material obtained from [C4mim][Tf2N], and {100} for material from [C3mimOH][Tf2N]. First‐principles density functional theory (DFT) calculations are used to support the experimental findings.

A review on tribological performance of ionic liquids as additives to bio lubricants

All the moving components in an internal combustion engine require a lubricant that allows smooth sliding and/or rolling of interacting surfaces. Lubricant not only minimizes the friction and wear but also dissipates the heat generated due to friction and removes debris from the area of contact. Environmental concerns, decreasing mineral oil reserves and difficult disposal of nonbiodegradable conventional lubricants have urged the researchers to shift towards environmental-friendly lubricants. Number of tribological studies carried out in the past have proved that ionic liquid-based bio-lubricants are sustainable and biodegradable alternative to mineral oils. This paper presents a brief review of properties of ionic liquids and their ability to reduce friction and wear between the interacting surfaces. Tribological performance and compatibility of ionic liquids with various base-oils have been compared under boundary lubrication. The results reveal that phosphonium-based ionic liquids namely tetra-decyl tri-hexyl phosphonium bis(2,4,4-trimethylpentyl) phosphinate (P66614)i(C8)2PO2 and tri-hexyl tetra-decyl phosphonium bis(2-ethylhexyl) phosphate (P-DEHP) are more suitable for tribological applications. Since, ionic liquids can be tailored according to the application and millions of combinations are possible therefore, there is a need to summarize the published data in a more systematic and logical way.

Photodegradation of Phenolic Compounds from Water in the Presence of a Pd-Containing Exhausted Adsorbent

A closed-cycle technology regarding the use of an exhausted Pd-based adsorbent as a photocatalyst in the degradation process of phenol is presented. Pd (II) represents a precious metal of great economic importance. Its obtained from natural sources become more difficult to achieve. Therefore, also considering the regulations of the “circular economy,” its recovery from secondary sources turn out to be a stringent issue in the last years. Pd(II) ions are removed from aqueous solution through adsorption onto Florisil (an inorganic solid support—magnesium silicate) impregnated with Cyphos IL 101 (trihexyl tetradecyl phosphonium chloride). It was observed that the presence of the ionic liquid (IL) in the adsorbent structure doubles the adsorption efficiency of the studied materials. The newly obtained Pd-based photocatalyst was exhaustively characterized and was used in the degradation process of phenol from aqueous solutions. The phenol degradation process was studied in terms of the nature of the photocatalyst used, time of photodegradation and solid: liquid ratio. It was observed that both the presence of IL and Pd lead to an increase in the efficiency of the phenol degradation process. The new Pd-based photocatalyst could be efficiently used in more cycles of phenol photodegradation processes. When is used as a photocatalyst the Florisil impregnated with IL and loaded with 2 mg/g of Pd, a degree of mineralization of 93.75% is obtained after 180 min of irradiation of a phenol solution having a concentration of 20 mg/L and using a solid:liquid ratio = 1:1.