Application Of Solvent Extraction Research Articles

Preparation of magnetic oil-based gel microspheres containing di(2-ethylhexyl)phosphoric acid for extraction of scandium ions at low concentrations in aqueous solutions

Extraction of low-concentration rare earths is one of the important paths for the sustainability of the rare earth industry. The research and development of materials suitable for the extraction of rare earth ions at low concentrations is of great significance. Currently, the application of solvent extraction in the rare earth production industry is highly mature. However, it is not economical to use it for the extraction of low concentration rare earths with problems of phase separation and organic phase loss. This work innovatively proposes to encapsulate the extractant and diluent in magnetic oleogel microspheres, which are obtained by solubilizing magnetic poly (phenyl divinylbenzene)(PS-DVB) microspheres with the extractant and diluent.. The magnetic PS-DVB microspheres of 3 ∼ 16 μm were prepared by suspension polymerisation, followed by encapsulation of di(2-ethylhexyl)phosphoric acid (D2EHPA) and dichloroethane in magnetic PS-DVB microspheres using emulsion swelling, and then magnetic oil-based gel microspheres containing D2EHPA with a particle size of 10 ∼ 32 μm were obtained. The magnetic oil-based gel microspheres containing D2EHPA consist of about 96 wt% liquid phase and about 4 wt% solid phase, with D2EHPA accounting for more than 4.19 wt%. The magnetic oil-based gel microspheres are very close to small oil droplets and are superparamagnetic. The magnetic oil-based gel microspheres containing D2EHPA could completely extract 60 ppm of scandium ions(Sc3+) under the conditions of O:A = 1:50,1:60,1:70, and the extraction equilibrium times were 6, 9 and 12 min, respectively. This extractant encapsulation scheme inherits the selectivity of traditional extractants while simultaneously preserving the advantages of rapid extraction by solvent extraction.

Novel-supported ionic liquid membranes for an effective removal of pentachlorophenol from wastewater

Recently ionic liquids (ILs) have been useful in many areas of wastewater treatment and separation processes in environmental engineering, such as supported ionic liquid membranes (SILM) based separations and solvent extraction applications. In this work novel ILs, namely 1-butyl-2,3-dimethyl imidazolium hexafluorophosphate [C4DMIM][PF6], tetrabutyl–phosphonium exafluorophosphate [TBP][PF6] were immobilized on PVDF (polyvinylidene fluoride) membrane for the removal of organic pollutant such as pentachlorophenol (PCP) from the water phase by SILM. Operating conditions like pH, feed and permeate concentration, membrane flux, and the mechanism was also studied. The interactions of H+ bonding, hydrophobic interactions, and carbon–π bonding interactions are explained via the SILM transport mechanism. The membranes were characterized by SEM, EDX, and FTIR analysis. In the experimental study, a high zetapotential of −93.24 mV was achieved, which is an indication of the excellent stability of SILM. At a pH of 4, [TBP][PF6] had the highest penetration rate of 87%. In contrast, [C4DMIM][PF6] yielded 79% after 30 h of experimentation at the feed pH 4. Similarly, after 30 h, [TBP][PF6] got the highest rate of permeation (80.50%), followed by [C4DMIM][PF6] (73.00%). The 0.1 M NaOH was used as a stripping agent in this study. PCP was successfully separated from the aqueous phase using two different hydrophobic ionic liquids as [C4DMIM][PF6] and [TBP][PF6]. This SILM technique has the potential in the future for further developments and for extracting organic contaminants from wastewater on a laboratory or industrial scale.

Microflow visualization and electrical signature of tri-n-butyl phosphate/n-dodecane and nitric acid in a centrifugal contactor

Despite the common use of centrifugal contactors in solvent extraction applications, no direct, high-speed visualization of the underlying microflow structure has been published in the open literature. The system in this study is the most prevalent solvent extraction combination used in the nuclear reprocessing industry to extract metal ions from spent nuclear fuel from a nitric acid aqueous solution into an organic mixture of tributylphosphate and dodecane. This study has identified details of the dispersed phase state at all flow conditions of interest, for instance, under common operation conditions the aqueous phase is typically dispersed even when the aqueous flowrate is significantly greater than the organic flowrate. This discovery may have implications when the centrifugal contactor is operated in a stripping mode. Visual observations of the images and simultaneous electrical resistivity measurement of the fluid mixture allowed for the identification of the phase inversion point and hysteresis region captured in a flow regime hysteresis plot. It is shown that it is possible to operate the contactor within the hysteresis region in a stable manner, therefore a choice can be made for the desired dispersed phase. This discovery may have favorable implications for the improved operation of the contactor in either the extracting or stripping modes. This work provides new direct experimental evidence of fluid flow for validating theory, modeling and simulation efforts; there is currently a lack of microflow insight. For instance, existing volume-averaged theories in fluid mechanics do not capture the phase inversion phenomena and/or its hysteresis, which in turn, invalidates predictions of mass transfer.

Effect of dilution on the performance of ionic liquids in milliflow solvent extraction applications: Towards integration of extraction, scrubbing and stripping operations with in-line membrane-based phase separation

The combination of ionic liquids (ILs) and millifluidic reactors is often suggested as a form of process intensification. The high viscosity of ILs has, however, raised concerns about hydrodynamics, mass-transfer enhancement and the ability to integrate several millifluidic operations. In the present study the performance of a quaternary ammonium hydrogensulfate IL, [A336][HSO4], in a millifluidic solvent extraction (SX) process was evaluated and compared with various, lower viscosity solutions of the IL in a diluent. Dilution of [A336][HSO4] significantly improved the slug flow hydrodynamics by reducing the film thickness, avoiding the loss of secondary recirculations inside the plugs and improving stability at elevated flow rates. The overall mass-transfer performance of the system was also improved upon dilution by a balancing of mass-transfer and reaction limitations. It was also observed that dilution reduced reagent consumption and improved the extraction selectivity. In addition, the decrease of the viscosity of the IL upon dilution facilitated the use of an in-line membrane-based phase separator. An integrated millifluidic set-up containing an extraction, scrubbing and stripping reactor was built using these in-line phase separators and applied to the SX purification of germanium from a synthetic zinc refinery residue leachate. The integrated reactor system was operated using a 30 vol% [A336][HSO4] dilution in p-cymene and successfully run for 4 h without any loss in separation performance or stability.

Yield and Quality Improvement of Candlenut Oil by Microwave Assisted Extraction (MAE) Methods

Candlenut (Aleurites moluccana L) is a native plant of Indonesia and one of the six spices with the highest export value. Candlenut is one of the nutraceutical ingredients, used as raw material for the cosmetic and pharmaceutical industries. Candlenut is used as a pain reliever and anti-inflammatory and has benefits in healing burns. The result of processed candlenut seeds, namely candlenut oil is rich in omega 3 unsaturated fatty acids which are anti-aging and strengthen and repair hair exposed to radiation. The problem faced in producing candlenut oil is the low yield and quality of the oil which is indicated by the brownish color of the oil and the long extraction time. This study aims to study increasing the yield of candlenut oil through the application of solvent extraction and microwave assisted extraction (MAE) methods and to identify the composition of the chemical compounds produced. The raw material used in producing this candlenut oil is candlenut seeds from the protected forest area of Register 21 PerentianBaru, Pringsewu Regency, Lampung Province. This research method is an experimental design with a completely randomized design. The independent variables in this study were the ratio of the sample to the amount of solvent with a level of 1;1; 1:2; 1:3 and 1:4. The observed responses were the yield, density and chemical composition of candlenut oil. The MAE method produced the highest yield of 38,5% in the ratio of the sample to the amount of solvent 1:2 with the characteristics of the oil produced, among others, a density of 0, 864 g/ml and a refractive index of 1,4772. The GCMS results show that the chemical compounds that make up candlenut oil include 31,1% linoleic acid, 27,85% oleic acid, 25,19% linolenic acid and 4,54% palmitic acid.

A New Application of Solvent Extraction to Separate Copper from Extreme Acid Mine Drainage Producing Solutions for Electrochemical and Biological Recovery Processes

Over the last decade, AMD waters have gained more attention as a potential source of metals due to the emerging need to recover or recycle metals from secondary resources. Metals recovery supports sustainability and the development of a circular economy with benefits for resource conservation and the environment. In this study, five extractants (Acorga M5640, LIX 54, LIX 622, LIX 622 N, and LIX 864) diluted (15% (v/v)) in Shell GTL with 2.5% (v/v) octanol were compared and evaluated for Cu recovery from an extreme AMD sample (5.3 ± 0.3 g/L Cu) collected at the inactive São Domingos Mine in the Iberian Pyrite Belt of Portugal. Of the five extractants, Acorga M5640 showed the best selective efficiency. Further tests showed that 30% (v/v) of this extractant was able to selectively extract ≈ 96.0% of the Cu from the AMD in one extraction step and all of the remaining Cu (to below detection) in three steps. Among the different stripping agents tested, 2 M sulfuric acid was the most efficient, with ≈ 99% of the Cu stripped, and the recyclability of the organic phase was confirmed in five successive cycles of extraction and stripping. Furthermore, contact time tests revealed that the extraction kinetics allows the transfer of ≈ 97% of the Cu in 15 min, and aqueous to organic phase ratios tests demonstrated a maximum loading capacity of ≈ 16 g/L Cu in the organic phase. Raising the concentration of Cu in the stripping solution (2 M sulfuric acid) to ≈ 46 g/L through successive striping steps showed the potential to recover elemental Cu using traditional electrowinning. Finally, a biological approach for Cu recovery from the stripping solution was evaluated by adding the supernatant of a sulfate-reducing bacteria culture to make different molar ratios of biogenic sulfide to copper; ratios over 1.75 resulted in precipitation of more than 95% of the Cu as covellite nanoparticles.Graphical

The interphase distribution of light REE Ce(III) and La(III) in system based on PEG-1500 – NaNO3 – H2O with the quaternary ammonium base addition

The problem of e-waste processing and recovery of valuable metals from such waste for the second use is attracting more and more scientists’ attention. Liquid extraction as one of hydrometallurgy steps is a traditional method for the metal recovery. However, application of solvent extraction is not meet the green chemistry principles due to organic solvents. Aqueous two-phase systems based on water-soluble polymers are promising alternative for hazardous organic solvents. In this work the dependencies of Ce(III) and La(III) distribution coefficients from process time and the initial quaternary ammonium base concentration have been achieved. Also, based on the Ce(III) and La(III) extraction isotherms it has been shown that the metals initial concentrations are highly affects the distribution coefficients of studied metals. The possibility of aqueous two-phase system application as a solvent for quaternary ammonium salt for light REE (Ce(III) and La(III)) extraction from water solution has been shown.

Dispersed-phase Volume Fraction and Flow Regimes in Oscillatory Liquid-Liquid Two-Phase Flow in Annuli: Comparison of Sieve-Plate and Baffle-Plate Internals

ABSTRACT Liquid-liquid two-phase flows are central to solvent extraction processes. In a columnar solvent extraction contactor, the turn-down ratio can be increased by imposing oscillatory flow over steady flow. This study compares dispersed phase volume fraction and flows regimes for oscillatory liquid-liquid two-phase flow in annuli having sieve-plate and baffle-plate internals. Such flows in annuli are important for specific solvent extraction applications requiring a high surface-to-volume ratio in the contactor geometry. For identical conditions, the volume fraction of the dispersed phase is found to be more in the annulus having baffle plates compared to the annulus having sieve plates. For both types of internals, an increase in dispersed phase velocity or continuous phase velocity, or oscillation velocity leads to enhancement in the volume fraction of the dispersed phase. The dispersed phase volume fraction increases when the spacing between sieve plates or baffle plates is reduced or when the fractional open area is reduced. Retention of the dispersed phase is more in the annulus having a smaller equivalent diameter. The annulus having baffle plates shows a faster transition from mixer-settler to dispersion regime or dispersion regime to the quasi-emulsion regime. Higher dispersed phase volume fraction in the annulus having baffle-plate internals suggests that it is more suitable for mass transfer than the annulus having sieve-plate internals. However, faster regime transitions in the annulus having baffle plates indicate that it is more prone to flooding than the annulus having sieve plates. The correlations that can be used to estimate the volume fraction of the dispersed phase are proposed. These correlations will be useful for design calculations.

Tuning Solvent Miscibility: A Fundamental Assessment on the Example of Induced Methanol/ n-Dodecane Phase Separation.

In this work, we assess the fundamental aspects of mutual miscibility of solvents by studying the mixing of two potential candidates, methanol and n-dodecane, for nonaqueous solvent extraction. To do so, 1H NMR spectroscopy and molecular dynamics simulations are used jointly. The NMR spectra show that good phase separation can be obtained by adding LiCl and that the addition of a popular extractant (tri-n-butyl phosphate) yields the opposite effect. It is also demonstrated that in a specific case the poor phase separation is not due to the migration of n-dodecane into the more polar phase, but due to the transfer of the extractant into it, which is especially relevant when considering industrial applications of solvent extraction. With the aid of molecular dynamics simulations, explanations of this behavior are given. Specifically, an increase of all hydrogen-bond lifetimes is found to be consequent to the addition of LiCl which implies an indirect influence on the methanol liquid structure, by favoring a stronger hydrogen-bond network. Therefore, we found that better phase separation is not directly due to the presence of LiCl, but due to the “hardening” of the hydrogen-bond network.

Recovery of lithium from underground brine by multistage centrifugal extraction using tri-isobutyl phosphate

The recovery of lithium from brine is a focus of worldwide due to the increasing demand of lithium in modern energy industry. Multistage centrifugal extraction was used in this work to recover lithium from underground brine. It was found that the centrifugal extraction rate of lithium is low by conventional methods, during which a multimolecular reaction with slow equilibrium time is involved. This problem was successfully solved by using an extraction system containing 80% tri-isobutyl phosphate (TIBP) and 20% sulfonated kerosene in combination with a novel operating method. The recycling of co-extractant (Fe3+) which is one of the bottleneck problems to limit the application of solvent extraction was also solved based on an innovative technical process. The recovery rate of lithium in underground brine reached to 90.05% by five-stage centrifugal extraction at optimized conditions. The stripping rate of lithium in organic phase was almost 100% using a solution containing 1.0 mol/L HCl at R(O/A) = 2:1. Lithium was not only separated from brine but also fourfold concentrated without any washing of the organic phase. This developed method is simple and thus is promising to be applied for the industrialized recovery of lithium from underground brine.

Extraction of In3+ and Fe3+ from sulfate solutions by using a 3D-printed “Y”-shaped microreactor

Abstract In traditional large-scale industrial applications of solvent extraction, there are some limitations such as low extraction efficiency, emulsification, co-extraction, and potential safety hazards. Recently, the application of microfluidic technology in solvent extraction has been dedicated to avoid the above problems effectively. However, manufacturing microchannels becomes a key problem before the application of such a new technology. In this article, the design and fabrication of a “Y”-shaped microreactor by using a three-dimensional (3D) printer, and its feasibility for extraction and separation, is illustrated. The extraction performance of a “Y”-shaped microreactor was investigated by carrying out the extraction of In3+ and Fe3+ from a sulfate solution under different experimental conditions. When the residence time was 210 s, the volume fraction of extractant (D2EHPA) was 30%, and the initial pH value of the aqueous solution was 0.7, the extraction rate of In3+ and the separation coefficient βIn/Fe were 98.07% and 1593, respectively. Remarkably, the handling capacity of the 3D-printed “Y” microreactor presented in this work with a channel length of 36 mm was superior, whereas the extraction rate of In3+ was very close to that of the previously reported microchip with a channel length of 120 mm.

Surface phenomena in air-assisted solvent extraction

Air-assisted solvent extraction (AASX) which is based on the coating of organic extractants on the air bubbles was developed to recover valuable metals from dilute Cu solutions. The effect of the chemical composition of aqueous and organic phases was investigated on the interfacial tension of aqueous/organic/air phases and related thermodynamic coefficients. Results were used to analyze the behaviour of phases and process efficiency in a continuous-mode AASX pilot plant. Interfacial data indicated that a suitable organic coating occurred in the presence of Flomin-F742, Nasfroth-240, and pine oil frothers with positive spreading coefficients. It was found that organic phase recycling in the AASX column was decreased from 86% to 13% by reducing the bubble size from 659 μm to 366 μm, respectively. By the addition of silicone oil dosage from 0 to 75 mg/L to the organic phase, Cu recovery was enhanced from 44% to 85% mainly as a consequence of decreasing the A/O phase ratio and increasing the coating degree of air bubbles by the organic extractant. An intense drop of organic phase recycling (from 70 to 30%) was observed at the silicone oil dosage beyond the critical micelle concentration of the organic phase, which was accompanied by producing a wide size range of air bubbles. It can be concluded that spreading the organic phase on the air bubbles and having a narrow size range of bubbles to overcome the upward velocity of bubbles to the downward velocity of the aqueous phase are the main issues for achieving a good efficiency in the AASX process. Results indicated that AASX method could widen the application of solvent extraction for the recovery of valuable metals from aqueous solutions.

Application of solvent extraction operation to recover rare earths from fluorescent lamps

The paper is focused on the application of solvent extraction for the recovery of rare earth elements from sulfuric leaching solutions obtained by the dissolution of fluorescent powders of lamps. The efficiency on rare earths extractions of three extractants, Cyanex 272, Cyanex 572 and D2EHPA in kerosene were investigated as a function of pH levels.Similar extraction for all the rare earths elements were observed, but the tests performed with D2EHPA showed that for pH values less than 1, yttrium and terbium could be extracted with yields higher than the other rare earths. The orders of the extraction were determined: yttrium ≥ terbium > gadolinium ≥ europium > cerium ≥ lanthanum. Further tests showed the optimal conditions, under the investigated ones, to extract yttrium with traces of terbium and cerium from sulfate leaching solutions. According to the experimental results, operating conditions of extractions were proposed in order to establish the guidelines for the following stripping and operation steps to recover rare earths selectively or at least in groups of them. A simulation of the proposed process was performed using a specific software in order to define the mass and energy balance of the entire recycling treatment of spent lamps.

Application of solvent extraction in the preparation of metal nano- and microparticles

The extraction of silver, nickel, copper, and bismuth from a solution of their salts by solutions of caprylic, 2-ethylhexanoic, and Versatic 10 and 913 acids in different diluents has been studied and the possibility of obtaining concentrated solutions of carboxylates of these metals has been shown. It has been established that the nature of carboxylic acid significantly affects the extraction of silver. The process of the thermal decomposition of metal-containing organic phases prepared as a result of the extraction of silver, nickel, copper, bismuth, lead, and cadmium by a solution of carboxylic acid in benzyl alcohol has been studied. The possibility of preparing metal powders of the micron and submicron size as a result of the thermal decomposition of solutions of metal-containing carboxylates in benzyl alcohol has been shown.

Development of solvent extraction methods for recovering rare earth metals

Published works conducted in Russia and other countries over the last 10–15 years regarding the application of solvent extraction in technological processes for recovering rare earth metals from various mineral and technogenic raw materials (bastnesite, monazite, loparite, xenotime, kularite, etc.) were analyzed in the present review. Raw materials containing rare earth are beneficiated by flotation, magnetic or gravity methods to produce rare earth concentrates, which are undergone hydrometallurgical processing. Rare earthcontaining concentrates or calcined residues are usually treated with inorganic acids. Then individual or mixed rare earths are extracted from pregnant leach solutions by solvent extraction. Various commercial extractants belonging to different classes are used for extraction. A large number of stages are usually required to separate rare earth metals.

The Effect of Alkyl Substituents on Actinide and Lanthanide Extraction by Diglycolamide Compounds

The effect of the alkyl substituents on amidic N atoms in diglycolamide (DGA) compounds on solvent extraction has been investigated. The solubility in water and n-dodecane, lanthanide loading capacity, and distribution ratios (D) of lanthanides and actinides for various DGA compounds are reported. DGA derivatives with short alkyl chains, for example, methyl and ethyl groups, are very water soluble, while DGA derivatives with long alkyl chains, for example, octyl (TODGA), decyl (TDDGA), dodecyl (TDdDGA), and 2-ethylhexyl (TEHDGA) group are moderately soluble in n-dodecane. DGA derivatives with phenyl substituents have very low solubility in both aqueous and organic solvents, which suggests that these compounds will not be suitable for solvent extraction applications in the HNO3/n-dodecane systems. The lanthanide loading capacities of DGA extractants correlate with their alkyl chain lengths according to the following order: TDdDGA > TDDGA > TODGA > TEHDGA. The branched-alkyl-chain DGA derivative (TEHDGA) exhibits both lower D and loading capacity than TODGA. The results of masking-effect and solubility tests indicate that TEDGA is the best actinide masking agent among the water-soluble DGA derivatives tested. Actinide and lanthanide extractions using ten DGA compounds in six diluents (nitrobenzene, 1,2-dichloroethane, 1-octanol, chloroform, toluene, and n-dodecane) are also reported; it was observed that lipophilic DGA derivatives with shorter alkyl chains show higher D values.

The use of environmentally sustainable bio-derived solvents in solvent extraction applications—A review

Replacement of volatile organic compounds (VOCs) by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over conventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction pilot plant studies.

A rapid and convenient method for preparative separation of three indissolvable polyphenols from Euphorbia pekinensis by the flexible application of solvent extraction combined with counter-current chromatography

A rapid and convenient method was established to preparatively isolate the three ellagic acid types of compounds, which were the main polyphenols in Euphorbia pekinensis, by flexibly applying solvent extraction combined with counter-current chromatography (CCC). The total extract (extracted using 95% ethanol) of E. pekinensis was pretreated by two simple steps before CCC isolation, following the procedure: the total extract was extracted by classical solvent extraction using petroleum ether and ethyl acetate, respectively, and then the ethyl acetate extract was suspended using 95% ethanol, after being allowed to stand overnight, the sediment was obtained. Partial sediment (100 mg) was then directly separated by CCC with a two-phase solvent system composed of chloroform-95% ethanol-water-85% formic acid (50:50:50:5, v/v/v/v). About 22 mg of 3,3'-dimethoxy ellagic acid (1), 12 mg of 3,3'-di-O-methyl-4-O-(β-D-xylopyranosyl)ellagic acid (2), and 35 mg of ellagic acid (3) with purities of 96.0, 95.2, and 95.4% were obtained respectively in one step within 4 h. After being purified by washing with methanol, the purities of the three compounds obtained were all above 98%. The purities were determined by HPLC and their chemical structures were further identified by (1)H and (13)C NMR spectroscopy. The recoveries were calculated as 84.6, 85.7, and 89.5%, respectively. The result demonstrated that the present isolation method was rapid, economical and efficient for the preparative separation of polyphenols from E. pekinensis.

Solvent extraction of metal ions by use of Schiff bases

Schiff bases are aldehyde or ketone like compounds in which the carbonyl group is replaced by imine or azomethine group. They are widely used for industrial purposes and also exhibit a broad range as extractants. A general view of solvent extraction applications of complexes is discussed in this review. The family of Schiff bases and their extraction of various transition metals such as Co, Cu, Cr, Fe, Ga, Hg, Mn, Mo and Ni are discussed. A brief history of the synthesis and reactivity of Schiff bases will be presented. Factors on solvent extraction will be illustrated and discussed.

Bitter-Tasting and Kokumi-Enhancing Molecules in Thermally Processed Avocado (Persea americana Mill.)

Sequential application of solvent extraction and RP-HPLC in combination with taste dilution analyses (TDA) and comparative TDA, followed by LC-MS and 1D/2D NMR experiments, led to the discovery of 10 C(17)-C(21) oxylipins with 1,2,4-trihydroxy-, 1-acetoxy-2,4-dihydroxy-, and 1-acetoxy-2-hydroxy-4-oxo motifs, respectively, besides 1-O-stearoyl-glycerol and 1-O-linoleoyl-glycerol as bitter-tasting compounds in thermally processed avocado (Persea americana Mill.). On the basis of quantitative data, dose-over-threshold (DoT) factors, and taste re-engineering experiments, these phytochemicals, among which 1-acetoxy-2-hydroxy-4-oxo-octadeca-12-ene was found with the highest taste impact, were confirmed to be the key contributors to the bitter off-taste developed upon thermal processing of avocado. For the first time, those C(17)-C(21) oxylipins exhibiting a 1-acetoxy-2,4-dihydroxy- and a 1-acetoxy-2-hydroxy-4-oxo motif, respectively, were discovered to induce a mouthfulness (kokumi)-enhancing activity in sub-bitter threshold concentrations.