Sulfonic Acid Cation Exchange Research Articles

Aqueous Lithium-Ion Battery with Dual Electrolytes at Equilibrium across Cation-Exchange Membrane Separator

Aqueous lithium-ion batteries (ALIBs) have been investigated as a promising safe and low-cost storage device for sustainable energy. For the stability of ALIBs, it is important to expand the electrochemical stability window of aqueous electrolytes. Although “Water-in-salt” electrolytes [1] containing significant amounts of lithium salts have been reported as an effective approach, cost reduction of the aqueous electrolyte remains a major challenge for the industrialization of such ALIBs.Controlling the pH of the aqueous electrolyte is another approach to widen the electrochemical window with a smaller use of lithium salts. The 2 V-class ALIB of Zn-coated Li4Ti5O12/LiMn2O4 was demonstrated using dual aqueous electrolytes having different pH separated by a lithium-ion conductive inorganic solid electrolyte.[2] However, lithium-ion conductive inorganic solid electrolytes may often be unstable in alkaline solutions. A perfluorinated sulfonic acid cation-exchange membrane (CEM) is one of the possible alternatives for separating two different aqueous electrolytes. In principle, the concentration of the entire electrolyte does not change during lithium-ion battery operation where lithium ions shuttle between the cathode and anode. Therefore, the specific compositions of the cathode and anode electrolytes are selected to achieve the Donnan equilibrium across the CEM, and stable battery operation is expected as long as the electrolyte equilibrium is maintained. In this study, the feasibility of this concept was investigated using ALIB cell of the anatase-TiO2/spinel-LiMn2O4.A stable combination of cathode and anode electrolytes was investigated experimentally. Several compositions of cathode and anode electrolytes were prepared, and equal volumes of the cathode and anode electrolytes were faced across the CEM, stored for 10 days at room temperature, and the composition of each electrolyte were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). After repeating this procedure, a stable combination of cathode and anode electrolytes was found as 27 g/L of Li and 8 g/L of K for an anode electrolyte, and 24 g/L of Li, 36 g/L of K, 41 g/L of P, and 68 g/L of S for a cathode electrolyte prepared using LiOH, KOH, Li2SO4, and KH2PO4. The pH was 4 and 11 for the cathode and anode electrolytes, respectively.The battery test was demonstrated for the TiO2/LiMn2O4 cells assembled with the cathode/anode electrolyte and the same 2 mol/kg Li2SO4 electrolyte in both sides for comparison. The initial charge/discharge profiles are shown in Fig. 1. The profiles were obtained by constant current of 15 mA/g regarding the weight of the cathode active material with the cutoff voltage of 2.8 V and 1.5 V in charge and discharge processes, respectively. The Coulombic efficiency was reached to 96% in the cells with electrolytes having the pH difference, whereas it was 69% in the cell with the 2 mol/kg Li2SO4. The alkaline anode electrolyte suppressed hydrogen generation sufficiently for the lithiation/delithiation of anatase TiO2, which leads to an excellent reversibility over 2 V operation with an improvement in the Coulombic efficiency of the cell with dual aqueous electrolytes.To further investigate the stability of the aqueous battery, a cycle test was conducted on the cell with the dual electrolytes. Figure 1(b) shows the discharge capacity during 100 charge-discharge cycles obtained by the constant current of 75 mA/g-cathode. The Coulombic efficiency reached >99%, and the capacity retention was calculated to be 75% at 100 cycles, which indicates that the suitable pH of the cathode and anode electrolyte was maintained during repeated charge/discharge cycles.In the presentation, we will discuss the details of the battery operation, including a role of perfluorosulfonated CEM and issues to improve the battery performance.

Recovery of Ionic Liquid from the Model Solution Mixture Mimicking the Catalytically Hydrolyzed Cellulose Product Utilizing Amberlyst Ion-Exchange Resin

The hydrolysis of cellulose using ionic liquid (IL) has been extensively studied but there is limited understanding of the removal of IL from the biomass hydrolysate. Finding a suitable method for the recovery and reuse of IL is one of the biggest challenges before its large-scale application. Selecting an appropriate combined recovery process is very important. This study proposed a facile ion-exchange combined method for the recovery of IL from the modeled cellulose hydrolysate mixture containing sugars as well as γ-valerolactone (GVL) via an adsorption–desorption mechanism using sulfonic acid cation-exchange (Amberlyst 15 (H)) resin. The results showed that the resin could adsorb more than 94% of 1-ethyl-3-methylimidazolium chloride [Emim]Cl IL at ambient conditions within a contact time of 20 min. The other coexisting constituents like glucose and GVL have no significant effect on the adsorption efficiency of IL. The adsorption of IL on Amberlyst 15 (H) resin was observed to be pseudo-second-order adsorption. The regeneration of the adsorbed IL was possible up to 70% using low-cost, easily available sodium chloride (NaCl) solution. Similarly, despite the interference of other unwanted byproducts in the real biomass hydrolysate sample, an IL adsorption efficiency up to 51% was reached under similar operating conditions. This study thus opens the facile possibility of extracting and recycling IL used in the biomass hydrolysis process.

A Comparative Study of the Catalytic Activity of Sulfonic Acid Cation-Exchange Resins with a Macroporous and Gel Structure in Fatty Acid Esterification

A Comparative Study of the Catalytic Activity of Sulfonic Acid Cation-Exchange Resins with a Macroporous and Gel Structure in Fatty Acid Esterification

UNSTEADY PROCESSES OF ION EXCHANGE SORPTION OF COPPER IONS IN A CONTINUOUS IDEAL MIXING APPARATUS

The article is devoted to the study of transient processes of ion-exchange sorption of heavy metal ions on a sulfonic acid cation exchanger in a vessel with a stirrer. A mathematical description of the ion exchange process is proposed, taking into account the following simplifying assumptions: at the initial moment of time, a solution and an ion exchanger containing heavy metal ions are inside the apparatus; the rate of ion exchange is limited by both internal and external diffusion; the process equilibrium is described by the Nikolsky adsorption isotherm equation; the structure of the movement of the solution and the ion exchanger in the apparatus is described by the ideal mixing model. In accordance with the accepted assumptions, a mathematical description of the process is formulated, including the equation of the material balance of the apparatus, the equation of the adsorption isotherm, the equation of diffusion kinetics, as well as the initial and boundary conditions of the third kind. The solution of the problem is carried out on an electronic computer by a numerical method, in which the characteristic equation of a continuous-action apparatus of complete mixing is used to find the unknown concentration of the solution. To test the adequacy of the developed model to the real process, experimental studies of transient processes of ion-exchange sorption of copper ions on the Lewatit S-100 sulfonic acid cation exchanger in a laboratory capacitive apparatus with a stirrer were carried out. During the research, acceleration curves were taken, on the basis of which the parameters of the non-stationary ion-exchange process were calculated: acceleration time, time constant, gain of the object and the maximum rate of change in the concentration of the solution at the outlet of the apparatus. Comparison of the results of calculation and experiment made it possible to conclude that the developed mathematical description is adequate to the real process. The discrepancy between the calculation and the experiment does not exceed 14%. Recommendations are given on the application of the obtained dependences for practical application.

A New Sulfonic Acid Cation-Exchange Resin Based on Polyvinyl Chloride and Its Evaluation in Water Softening

A New Sulfonic Acid Cation-Exchange Resin Based on Polyvinyl Chloride and Its Evaluation in Water Softening

Sorption of Pyridine-3-carboxylic Acid by Fe-Containing Sulfonic Acid Cation Exchanger KU-2

Sorption of Pyridine-3-carboxylic Acid by Fe-Containing Sulfonic Acid Cation Exchanger KU-2

Purification of Wet-Process Phosphoric Acid via Donnan Dialysis with a Perfluorinated Sulfonic Acid Cation-Exchange Membrane.

This work reports the application of an electromembrane process, Donnan dialysis (DD), for the purification of so-called wet-process phosphoric acid (WPA). Nitric acid is used as the stripping solution to remove metallic cations (mostly Fe3+, Al3+, and Mg2+) that are harmful to the further processing of WPA. The paper first presents a set of experimental data on the measurements of the metallic cation fluxes through a perfluorinated sulfonic acid cation-exchange membrane. Not only WPA, but also synthetic phosphoric acid solutions with mixed metallic cations (MPA) and with a single metallic cation (SPA) were studied. This confrontation confirms (1) that the order of metallic cations fluxes is Mg2+ > Al3+ > Fe3+; (2) that, compared with MPA, the purification effect of WPA causes only negligible change; (3) that, by comparing the DD processes with SPA and MPA solutions, the reason for the low transmembrane fluxes of Fe3+ and Al3+ could be explained by the large ionic charge and large hydrated ion radius. Furthermore, by analyzing the ion composition of membranes equilibrated in SPA solutions, we conclude that the forms of cations in the membrane are most likely Fe3+, Al3+, and Mg2+.

Removal of Zn2+ from polyethylene terephthalate (PET) glycolytic monomers by sulfonic acid cation exchange resin

Glycolysis of polyethylene terephthalate (PET) has always been a research hotspot in PET waste recovery due to its high efficiency and sustainability. Zinc acetate (ZnAc2•2H2O) and urea/(ZnAc2•2H2O) are usually regarded as the most promising catalysts for the glycolysis of PET, while the residue of Zn2+ in glycolytic monomers (bis(hydroxyalkyl) terephthalate (BHET)) was identified as a big hassle, which caused the detrimental effect on the chromaticity of down-stream product. However, the removal of Zn2+ from BHET has almost not been reported previously. In the present work, ion exchange was adopted as effective measure to eliminate trace Zn2+ from BHET and more than 99% of Zn2+ can be removed by 001*7 sulfonic acid resin with resin dosage of 1.6 g/L at 298.15 K, 160 rpm for 120 min. Additionally, based on prevailing adsorption kinetics, isotherms, thermodynamic models and various precise instruments, comprehensive adsorption mechanism were exploited. Pseudo-second-order model (R2 > 0.999) and Langmuir model (R2 > 0.999) were found to match well with the experimental data, indicating the sorption of Zn2+ on 001*7 was homogeneous monomolecular layer adsorption and dominated by chemisorption. The thermodynamic model revealed the sorption was thermodynamically spontaneous. Fourier-Transform Infrared Spectroscopy (FTIR) illuminated the sulfonic acid groups on 001*7 resin were the main binding sites for Zn2+. X-ray Photoelectron Spectroscopy (XPS) elucidated ion exchange and electrostatic interaction between the sulfonic acid groups and Zn2+ were responsible for the sorption of Zn2+. All the results obtained can prove 001*7 sulfonic acid resin is an efficient material for removal of Zn2+ from BHET.

Константы равновесия сорбции пиридинкарбоновых кислот сульфокатионитом полистирольного типа

The processes of sorption of pyridine-3-carboxylic (nicotinic) and pyridine-4-carboxylic (isonicotinic) acids by sulfonic acid cation exchangers of the polystyrene type (CU-2-4 and CU-2-8) from aqueous solutions with different pH values were studied. Analysis of the FTIR spectra of isonicotinic acid, isonicotinic acid sulfate, and CU-2-8 sulfonic cation exchanger filled with isonicotinic acid showed that pyridinecarboxylic acid is in the protonated form in the polymer phase. Experimental data of the equilibrium distribution of acids in the aqueous solution-cation exchange system have been obtained. The values of the equilibrium constants for ion exchange and ligand sorption processes involving various forms of pyridinecarboxylic acid, sulfonic cation exchanger, and protons were calculated. The equilibrium constants for the ion exchange of sulfocationite protons by pyridinecarboxylic acid cations from solution are in the range 3.3-4.4. The selectivity of sulfonic cation exchangers to cations increases in the sequences proton < nicotinic acid cation < isonicotinic acid cation. The values of the equilibrium constant for ligand sorption of molecules are 195-220 dm3/mol for isonicotinic acid and reach 320-330 dm3/mol for nicotinic acid, i.e. the sorption activity of the H-form of the cation exchanger is higher in relation to nicotinic acid molecules. A change in the amount of a crosslinking agent (from 4% to 8% divinylbenzene) in a polystyrene type sulfonic cation exchanger does not significantly affect its sorption activity towards pyridinecarboxylic acids.

The Role of the Dependence of the Enthalpy of Ion Exchange on Temperature in Predicting the Behavior of Ion-Exchange Systems

The effect of temperature on the exchange of di- and monovalent ions on polymethacrylic and polyacrylic cation exchangers in the range from 298 to 413 K is studied. It is shown that the differential enthalpy and the equilibrium coefficient simultaneously increase with temperature. The dependences of the enthalpy on temperature are linear. The effect of temperature on the enthalpy of ion exchange observed for all studied ion exchangers is much more strong than in the systems described in the literature with sulfonic acid cation exchangers and highly basic anion exchangers. The problem of taking into account the dependence of enthalpy on temperature when predicting the behavior of ion-exchange systems is discussed.

Каталитическое окисление катионита КУ-2×8 водным раствором пероксида водорода

During the operation of nuclear power plants, spent ion-exchange resins are formed, which are heterogeneous radioactive low-level waste in the form of particles from a cross-linked organic polymer. Such resins may not always be regenerated. Therefore, the disposal of spent ion exchange resins is currently one of the primary problems at nuclear power plants. Conventional technologies for the processing of waste resins are relatively expensive. In addition, there are difficulties with transportation and storage of waste, and the disposal of spent ion exchange resins is a complex process. In the present study, an attempt has been made to solve the problem of spent ion-exchange resins utilization on example of the sulfonic acid cation exchanger’s KU-2×8 oxidative degradation with the Fenton reaction. The decomposition of the cation exchanger was carried out with 20% hydrogen peroxide in the temperature range 323-353 K in the presence of a catalyst – low concentration copper(II) sulfate (0.001-0.009 mmol/l). The influence of process temperature and catalyst concentration on the reaction rate was estimated. When determining the rate of the cation exchanger KU-2×8 heterogeneous oxidation reaction with hydrogen peroxide in the presence of a catalytic additive, the spherical shape of the sorbent granules, the surface area of which changed during reaction, was taken into account. It was shown that with a reaction temperature increasing from 323 to 353 K, the rate constant of cation exchanger's oxidative decomposition have increased by a factor of 20-37. The activation energy values of the sulfonic acid cation exchanger's KU-2×8 decomposition with hydrogen peroxide in the presence of copper(II) sulfate are 89.7-115.2 kJ/mol, which indicates that the process is in the kinetic mode. It was established with electron-microscopic studies that the beads of the cation exchanger KU-2×8, when decomposed in H2O2 solution in the presence of a catalyst can stick together, change their shape and volume, and their surface becomes covered with cracks. The studies performed showed almost complete catalytic decomposition of cation exchanger KU-2×8 in a hydrogen peroxide solution at 323-353 K after 420-220 minutes, which allows accelerating the oxidation at relatively low temperatures.

Ion Transfer during the Electrochemical Reduction of Oxygen on Copper–Ion Exchange Nanocomposites

The electrochemical reduction of oxygen dissolved in water is studied using a thin granular layer of nanocomposites of copper–sulfonic acid cation exchanger in different ionic forms (H+, Na+). It is established there is considerable acceleration of oxygen absorption in the initial period under the simultaneous impact of electrical polarization and chemical activity of nanocomposites, especially in the H+-form. The rate of the process later slows and reaches a constant value regardless of the ionic form of the nanocomposite and without changing the pH or electrical conductivity of water. Products of the oxidation of metal nanoparticles form as insular nuclei distributed over the volume of nanocomposite granules; some grains are oxidized with the formation of sharp boundaries of oxide layers. A stationary mode of oxygen absorption is established due to the constant generation of hydrogen ions required for the reaction on anodes and the regeneration of copper nanoparticles on cathodes. It is concluded that these patterns are based on conjugate processes of ion transfer, electrochemical and chemical oxygen reduction, and the oxidation and reduction of copper nanoparticles.

IR Spectroscopic Study of the Mechanism of Phenylalanine Sorption from Aqueous Solutions by a Shaped Sulfonic Acid Cation-Exchange Membrane with a Styrene–Divinylbenzene Matrix

The mechanism of phenylalanine absorption by a shaped sulfonic acid cation-exchange membrane with a styrene-divinylbenzene matrix was studied by IR spectroscopy. An analysis of the results of the IR spectroscopic studies showed that the interaction in the sorbent–sorbate system is based on ion-exchange sorption via protonation with addition of the hydrogen counterion to the carboxyl group of amino acid and ion exchange with displacement of the hydrogen ion into the equilibrium solution. The occurrence of nonexchange sorption due to the additional interparticle interactions characteristic of the aromatic amino acid of phenylalanine was proven by sorbate association in the polymer material.

Removal of Ionic Liquids from Oil Sands Processing Solution by Ion-Exchange Resin

Ionic liquids (ILs) have been reported to be good process aids for enhanced bitumen recovery from oil sands. However, after the extraction, some ionic liquids are left in the residual solids or solutions. Herein, a washing–ion exchange combined method has been designed for the removal of two imidazolium-based ILs, ([Bmim][BF4] and [Emim][BF4]), from residual sands after ILs-enhanced solvent extraction of oil sands. This process was conducted as two steps: water washing of the residual solids to remove ILs into aqueous solution; adsorption and desorption of ILs from the solution by the sulfonic acid cation-exchange resin (Amberlite IR 120Na). Surface characterization showed that the hydrophilic ionic liquids could be completely removed from the solid surfaces by 3 times of water washing. The ionic liquids solution was treated by the ion-exchange resin. Results showed that more than 95% of [Bmim][BF4] and 90% of [Emim][BF4] could be adsorbed by the resins at 20 °C with contact time of 30 min. The effects of some typical coexisted chemicals and minerals, such as salinity, kaolinite (Al4[Si4O10](OH)8), and silica (SiO2), in the solution on the adsorption of ionic liquids have also been investigated. Results showed that both kaolinite and SiO2 exerted a slight effect on the uptake of [Bmim][BF4]. However, it was observed that increasing the ionic strength of the solution by adding salts would deteriorate the adsorption of [Bmim]+ on the resin. The adsorption behaviors of two ILs fit well with the Sips model, suggesting the heterogeneous adsorption of ionic liquids onto resin. The adsorption of ionic liquids onto Amberlite IR 120Na resin was found to be pseudo-second-order adsorption. The regeneration tests showed stable performance of ion-exchange resins over three adsorption–desorption cycles.

Features of the supercritical CO2-assisted immobilization of fluorinated tetraphenylporphyrins into tetrafluoroethylene copolymers

The immobilization of fluorinated tetraphenylporphyrins (FTPPs) into tetrafluoroethylene copolymers (fluoroplast F-42 and MF-4SK, a perfluorinated sulfonic acid cation exchanger in H+-form) is conducted in supercritical CO2 (scCO2). The effects the conditions of immobilization (the temperature and pressure of scCO2, reaction time, and the addition of cosolvents) and the structure of the carrier polymer have on the content of porphyrin in these polymers is studied. The porphyrin-loaded polymer systems are shown to exhibit photosensitizing activity in anthracene and cholesterol oxidation in scCO2. Under conditions of photocatalysis, chemical and functional stability is a feature of only MF-4SK polymer systems; this is attributed to the formation of protonated forms of the porphyrins and their interaction with SO3 −-groups of the polymer (an ion exchange process), which prevents leaching of the FTPP from the polymer matrix. The photocatalytic process actually occurs inside the matrix of the perfluorinated copolymer, with the protonated form of the porphyrin acting as a photosensitizer. The rate constant of anthracene photooxidation in the presence of FTPP-loaded MF-4SK films in scCO2 is found to pass through a maximum as a function of the porphyrin content and the polymer film thickness. The use of such catalytic systems for cholesterol photooxidation in scCO2 is shown to produce a virtual monoproduct (yield, ~10%): 6-formyl-B-norcholestane-3,5-diol, a compound with high biological activity.

Furfural based policondensation type sulfonic acid cation-exchange resin

Furfural based policondensation type sulfonic acid cation-exchange resin

Magnetic graphene – polystyrene sulfonic acid nano composite: A dispersive cation exchange sorbent for the enrichment of aminoalcohols and ethanolamines from environmental aqueous samples

Present study aimed at graphene surface modification to achieve selective analyte binding in dispersive solid phase extraction. Magnetic graphene – polystyrene sulfonic acid (MG-PSS) cation exchange nano-composite was prepared by non-covalent wrapping method. Composite was characterized by FT-IR and zeta potential. Material exhibited good dispersion in water and high exchange capacity of 1.97±0.16mMg−1. Prepared nano-sorbent was then exploited for the cation exchange extraction and gas chromatography mass spectrometric analysis of Chemical Weapons Convention relevant aminoalcohols and ethanolamines from aqueous samples. Extraction parameters such as sorbent amount, extraction time, desorption conditions and sample pH were optimized and effect of common matrix interferences such as polyethylene glycol and metal salts was also studied. Three milligram of sorbent per mL of sample with 20min of extraction time at room temperature afforded 70–81% recoveries of the selected analytes spiked at concentration level of 1μgmL−1. Method showed good linearity in the studied range with r2≥0.993. The limits of detection and limits of quantification ranged from 23 to 54ngmL−1 and 72 to 147ngmL−1, respectively. The relative standard deviation for intra- and inter-day precision ranged from 4.6 to 10.2% and 7.4 to 14.8% respectively. Applicability of the method to different environmental samples as well as the proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW) was also ascertained.

Stabilization of copper nanoparticles with volume- and surface-distribution inside ion-exchange matrices

Nanocomposites characterized by the surface and volume distributions of deposited copper nanoparticles are obtained via the chemical deposition of copper onto sulfonic acid and carboxylic cation exchanger and strongly basic anion exchanger matrices. The electrode behavior of the synthesized composites in CuSO4 solution is studied by open-circuit chronopotentiometry. The effect the nature of the fixed centers of the ion-exchange matrix has on the initial state of metallic particles and the processes that occur in solutions of their metal ions is established from the deviation of the nanocomposites’ electrode potential from the potential of a compact electrode and the nature of its change over time. It is shown that the mechanism behind the interaction of the matrix and metal ions (ion exchange, non-exchange absorption, complexation) determines not only the initial size and distribution of metal particles, but also the rate at which they achieve aggregative stability.

Versatility of cinchona-based zwitterionic chiral stationary phases: Enantiomer and diastereomer separations of non-protected oligopeptides utilizing a multi-modal chiral recognition mechanism

Cinchona alkaloid-based zwitterionic chiral stationary phases with diverse sulfonic acid cation exchanger groups were applied for enantiomer separations of small homochiral oligopeptides (all-l/all-d Ala-n, Val-n, Phe-n) using slightly acidic polar-organic mobile phase conditions which facilitated the ionization of ion exchanger sites of the chiral selectors as well as promoting zwitterion formation of the chiral selectands. Our studies focused on retention factors and selectivity as the main chromatographic parameters illustrating selector–selectand interactions. The results confirmed that bulky, aromatic side chains such as the benzyl group of Phe are analyte-inherent structural features promoting enantiorecognition. Regarding the zwitterionic selectors, a flexible spacer between the anion exchanger-carbamoyl and the cation exchanger sites was found to enhance stereoselectivity toward bulky and aromatic peptides while a rigid cation exchanger moiety contributed favorably to enantiomer distinction of peptides with small, aliphatic side chains. The investigations included all 28 stereoisomers of Phe-2 through Phe-4 to demonstrate the applicability of zwitterionic chiral stationary phases for the separation of sequential stereoisomers. Selectivity was shown to be governed by the Cinchona alkaloid motif but heavily dependent on effective hydrogen bonding between the carbamoyl motif and the amide groups of the peptide backbone. Contrary to previous studies on enantioselectivity which found pseudo-enantiomeric behavior of quinine and quinidine-based CSPs, in peptide stereoisomer separations CSPs based on quinidine undeniably performed better.

Optimization of alkylphenols used as semiproducts in the production of additives on Amberlyst 36Dry macroporous sulfonic acid cation-exchange resin

The synthesis of alkylphenols used as semiproducts in the production of lube oil additives via the alkylation of phenol by ethylene oligomers in the presence of Amberlyst 36Dry macroporous catalyst is studied. The proposed Amberlyst 36Dry sulfonic acid cation-exchange resin allows us to simplify appreciably its pretreatment before use, and to increase the time of its operation, along with the rate, conversion, and selectivity of the process relative to the traditional KU2-8ChS catalyst. Ethylene oligomers containing the maximum amount of vinylidene and internal olefins are established to be most active in alkylation. Linear α-olefins are much less active in alkylation. The ratio of ortho- and para-alkylphenols is generally determined by the temperature and structure of olefins and remains nearly constant with an increase in the process time. The rate of converting alkylphenyl esters into alkylphenols is found to depend on the structure of the ester alkyl radical. Alkylphenols, which fully correspond to the imposed technical requirements as semiproducts used in the production of additives, can be synthesized with a nearly quantitative yield with respect to ethylene oligomers at 135.0°C and a molar ratio ethylene oligomers : phenol = 1.0 : 6.0.