Synthesis and Characterization of the Inclusion Complex of Dicationic Ionic Liquid and β-Cyclodextrin

The supramolecular structure of the inclusion complex of β-cyclodextrin (β-CD) with 1,1',2,2'-tetramethyl-3,3'-(p-phenylenedimethylene) diimidazolium dibromide (TetraPhimBr), a dicationic ionic liquid, has been investigated. The inclusion complex with 1:1 molar ratio was prepared by a kneading method. Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD) analysis, (1)H NMR and thermogravimetric analysis (TGA) confirmed the formation of the inclusion complex. The results showed that the host-guest system is a fine crystalline powder. The decomposition temperature of the inclusion complex is lower than that of its parent molecules, TetraPhimBr and β-CD individually.     

Inclusion Complex of Sea Buckthorn Fruit Oil with β-Cyclodextrin: Preparation Characterization and Antioxidant Activity

This study aims to produce an inclusion complex between β-cyclodextrin (β-CD) and sea buckthorn fruit oil (SBFO) by using the saturated aqueous solution method and then to compare the resultant solution with the crude mixtures. In this study, the SBFO is extracted by Soxhlet extraction, which is optimized through the single-factor test. The main constituent of the SBFO is identified by gas chromatography-mass spectrometry (GC-MS), which confirms eight fatty acids. Fourier transform infrared spectroscopy, thermogravimetric analysis-differential scanning calorimetry, optical microscopy, scanning electron microscopy, and the result-characterized synthesized compounds confirm the formation of stable inclusion compounds by the SBFO with β-CD. The yield values of the inclusion complex and the SBFO loading content are 64.87 ± 2.26% and 9.2 ± 1.58%, respectively. Comparing the crude fruit oil, β-CD–SBFO, and saponified fruit oil reveals differences in their 2,2-diphenyl-1-pycrylhydrazyl and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonate) antioxidant activities. These findings suggest that the SBFO inclusion complex after β-cyclodextrin is stabilized and is a good antioxidant. This solution improves the inadequacy of the water solution and the instability of the SBFO. This study also implies that β-CD is a cost-effective and straightforward carrier for extending the applications of SBFO as a food or medicinal additive. Practical applications: In this experiment, the SBFO is converted from oil to powder to increase its efficacy as an additive to health and food products.     

Formation of a Polymer-Coated Inclusion Complex of D-Limonene and β-Cyclodextrin by Spray Drying

The polymer-coated inclusion complex powder formation of D-limonene and β-cyclodextrin obtained by spray drying was investigated with respect to the effects of various types of polymer coating agents on the powder particle size and morphology. The addition of the polymer coating agent affected the average particle size, morphology, and internal structures of the spray-dried powders. The average particle diameter of the uncoated spray-dried powders was approximately 5 µm. The powder particle size increased upon the addition of a polymer coating reagent. With the addition of 9 wt% of the polymer coating agent, an average diameter of approximately 80 µm was obtained for the spray-dried powder particles. However, further addition showed a negligible effect on the particle size. Inclusion complex crystals were observed on the surface and inside of the powder particles.     

Synthesis and Characterization of β-Cyclodextrin Functionalized Ionic Liquid Polymer as a Macroporous Material for the Removal of Phenols and As(V)

β-Cyclodextrin-ionic liquid polymer (CD-ILP) was first synthesized by functionalized β-cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using a toluene diisocyanate (TDI) linker to form insoluble CD-ILP (βCD-BIMOTs-TDI). The βCD-BIMOTs-TDI polymer was characterized using various tools and the results obtained were compared with those derived from the native β-cyclodextrin polymer (βCD-TDI). The SEM result shows that the presence of ionic liquid (IL) increases the pore size, while the thermo gravimetric analysis (TGA) result shows that the presence of IL increases the stability of the polymer. Meanwhile, Brunauer-Emmett-Teller (BET) results show that βCD-BIMOTs-TDI polymer has 1.254 m²/g surface areas and the Barret-Joyner-Halenda (BJH) pore size distribution result reveals that the polymer exhibits macropores with a pore size of 77.66 nm. Preliminary sorption experiments were carried out and the βCD-BIMOTs-TDI polymer shows enhanced sorption capacity and high removal towards phenols and As(V).     

Studies on Surfactant–Ionic Liquid Interaction on Clouding Behaviour and Evaluation of Thermodynamic Parameters

The present study investigates the effect of tetraethyl ammonium tetrafluoroborate [TEA(BF₄)] ionic liquid (IL) on the cloud point (CP) of the following nonionic surfactants in aqueous solution: ter‐octylphenol ethoxylates with 9.5 and 4.5 ethylene oxide groups (abbreviated TOPEO9.5 and TOPEO4.5, respectively), cetyl alcohol ethoxylate with 10 ethylene oxide groups (C16EO10), and sorbitan monolaurate and monooleate both with 20 ethylene oxide groups (SMLEO20 and SMOEO20, respectively) in aqueous solutions. The thermodynamic parameters of these mixtures were calculated at different IL concentrations. The CP of most of the tested nonionic surfactants increased with the increment of IL concentrations with the exception of C16EO10 for which it decreased. The solubility of a nonionic surfactant containing polyoxyethylene (POE) hydrophilic chain was considered as maximum at the CP, hence the thermodynamic parameters were calculated at the same temperature. The results showed that the standard Gibbs free energy (?G_CP⁰), the enthalpy (?H_CP⁰) and the entropy (?S_CP⁰) of the clouding phenomenon were found to be positive for ethoxylated octylphenol and sorbitan esters, whereas ?H_CP⁰ and ?S_CP⁰ were found to be negative for C16EO10. It was found that the overall clouding process is endothermic for ethoxylated octylphenol and sorbitan esters and exothermic for C16EO10. For all the studied systems, ?H_CP⁰ > T?S_CP⁰ indicated that the process of clouding is guided by both enthalpy and entropy. The positive value of standard Gibbs free energy (?G_CP⁰) for the all mixed systems indicated that the process proceeds non‐spontaneously. The ?G_CP⁰ decreased with increasing IL concentration for all the nonionic surfactants; however, it decreased with increasing surfactant concentration for TOPEO9.5, C16EO10, and SMOEO20, and increased with increasing surfactant concentration for TOPEO9.5 and SMLEO20.     

Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System

Several fundamental extraction parameters such as the kinetics and loading were studied for a new type of metal solvent extraction system with ionic liquids. The binary mixture of the ionic liquid betainium bis(trifluoromethylsulfonyl)imide and water shows thermomorphic behavior with an upper critical solution temperature (UCST), which can be used to avoid the slower mass transfer due to the generally higher viscosity of ionic liquids. A less viscous homogeneous phase and mixing on a molecular scale are obtained when the mixture is heated up above 55 °C. The influence of the temperature, the heating and cooling times, were studied for the extraction of neodymium(III) with betaine. A plausible and equal extraction mechanism is proposed in bis(trifluoromethylsulfonyl)imide, nitrate, and chloride media. After stripping of the metals from the ionic liquid phase, a higher recovery of the ionic liquid was obtained by salting-out of the ionic liquid fraction lost by dissolution in the aqueous phase. The change of the upper critical solution temperature by the addition of HCl or betaine was investigated. In addition, the viscosity was measured below and above the UCST as a function of the temperature.     

Competitive Binding of Off-Flavor Compounds with Soy Protein and β-Cyclodextrin in a Ternary System: A Model Study

Removal of soy protein (SP)-bound 2-nonanone by β-cyclodextrin (βCD) was studied using an equilibrium dialysis technique. It was observed that in the presence of βCD, a significant (p < 0.05) amount of SP-bound 2-nonanone could be removed in a concentration-dependent manner. Up to 94% of SP-bound 2-nonanone was stripped from SP when 6 mM βCD was present in the system. However, in thermodynamic terms, the net standard free energy change for transfer of 2-nonanone from SP to βCD, i.e., \( \Updelta \Updelta G^\circ_{{{\text{SP}} \to \beta {\text{CD}}}} \), was essentially zero, implying that the apparent equilibrium binding constant for the formation of βCD–2-nonanone complex was essentially same as that for the SP–2-nonanone complex formation in the ternary system. This indicated that stripping-off of 2-nonanone from SP by βCD was driven by the mass action ratio. Based on these results, it is shown that βCD can be used effectively for removing SP-bound off-flavor carbonyl compounds.     

Study on β-cyclodextrin grafting with chitosan and slow release of its inclusion complex with radioactive iodine

β-CD-2-CTS was synthesized by β-cyclodextrin reacting with p-toluenesulfonyl chloride, then grafting with chitosan. The infrared spectra analysis and ¹³C NMR confirmed that β-cyclodextrin reacted with p-toluenesulfonyl chloride at the 2-position carbon atom in the substituted glucose unit of β-cyclodextrin and formed β-CD-2-OTs. In the ¹³C NMR of β-CD-2-OTs, the characteristic peak of the 2-postion carbon atom in the substituted glucose unit of β-cyclodextrin appeared at 78.43 ppm. β-CD-2-CTS was characterized with infrared spectra analysis and X-ray diffraction. In the infrared spectra of β-CD-2-CTS, the characteristic peak of α-pyanyl vibration of β-CD was at 848.6 cm⁻¹. The characteristic peak of β-pyanyl vibration of CTS was at 894.9 cm⁻¹. The X-ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in β-CD-2-CTS. The polymer inclusion complex of β-CD-2-CTS with iodine was prepared and its inclusion ability was studied. The experimental results showed that a nice bit of iodine was included with β-CD-2-CTS and formed a stable inclusion complex. After the subcutaneous implantation of the polymer inclusion complex of β-CD-2-CTS with ¹³¹I₂ in rats, ¹³¹I₂ exhibited the property of slow release. ¹³¹I₂ in the blood of rats decreased slowly. ¹³¹I₂ in the blood of rats maintained approximately half of maximum for 70 days later, and maintained much higher radioactivity in the organs of rats compared to the inclusion complex of β-CD with ¹³¹ I₂, too. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2414–2421, 2001     

Effect of β-Cyclodextrin Complexation on Solubility and Enzymatic Conversion of Naringin

In the present paper, the effect of β-cyclodextrin (β-CD) inclusion complexation on the solubility and enzymatic hydrolysis of naringin was investigated. The inclusion complex of naringin/β-CD at the molar ratio of 1:1 was obtained by the dropping method and was characterized by differential scanning calorimetry. The solubility of naringin complexes in water at 37 ± 0.1 °C was 15 times greater than that of free naringin. Snailase-involved hydrolysis conditions were tested for the bioconversion of naringin into naringenin using the univariate experimental design. Naringin can be transformed into naringenin by snailase-involved hydrolysis. The optimum conditions for enzymatic hydrolysis were determined as follows: pH 5.0, temperature 37 °C, ratio of snailase/substrate 0.8, substrate concentration 20 mg·mL⁻¹, and reaction time 12 h. Under the optimum conditions, the transforming rate of naringenin from naringin for inclusion complexes and free naringin was 98.7% and 56.2% respectively, suggesting that β-CD complexation can improve the aqueous solubility and consequently the enzymatic hydrolysis rate of naringin.     

Effect of γ-Cyclodextrin Inclusion Complex on the Absorption of R-α-Lipoic Acid in Rats

R-α-lipoic acid (RLA) is an endogenous organic acid, and works as a cofactor for mitochondrial enzymes and as a kind of antioxidant. Inclusion complexes of RLA with α-, β- or γ-cyclodextrins (CD) were prepared and orally administered as a suspension to rats. Among them, RLA/γ-CD showed the highest plasma exposure, and its area under the plasma concentration-time curve (AUC) of RLA was 2.2 times higher than that after oral administration of non-inclusion RLA. On the other hand, the AUC after oral administration of non-inclusion RLA and RLA/γ-CD to pylorus-ligated rats did not differ. However, the AUC after intraduodenal administration of RLA/γ-CD was 5.1 times higher than that of non-inclusion RLA, and was almost comparable to the AUC after intraduodenal administration of RLA-Na solution. Furthermore, the AUC after intraduodenal administration of RLA/γ-CD was not affected by biliary ligation or co-administration of an amylase inhibitor. These findings demonstrated that RLA was absorbed from the small intestine effectively when orally administered as a γ-CD inclusion complex, which could be easily dissolved in the lumen of the intestine. In conclusion, γ-CD inclusion complex is an appropriate formulation for supplying RLA as a drug or nutritional supplement with respect to absorption.     

Synthesis of a Novel Strong Brønsted Acidic Ionic Liquid and its Catalytic Activities for the Oxathioacetalization

The novel efficient procedure has been developed for the oxathioacetalization of carbonyl compounds and 2-mercaptoethanol at room temperature under solvent-free condition. The results showed that the novel multi-SO₃H functionalized ionic liquid was very efficient for the reactions with the good to excellent yields in short time. Operational simplicity, without need of any solvent, room temperature, low cost of the catalyst used, high yields, applicability to large-scale reactions, reusability and chemoselectivity are the key features of this methodology.     

Adsorption of Basic Dyes on β-Cyclodextrin Functionalized Poly (Styrene-Alt-Maleic Anhydride)

A new [#x003B2]-cyclodextrin functionalized poly (styrene-alt-maleic anhydride) was synthesized for removal of basic fuchsin (BF) and methylene blue (MB) from water via grafting reaction of [#x003B2]-cyclodextrin onto poly (styrene-alt-maleic anhydride) and then acylation with chloroacetyl chloride. Its structure was characterized. At a dosage of 0.25 g[#x000B7]L^[#x02212]1, pH 6, and 25[#x000B0]C, adsorption equilibrium was reached in 600 min and maximum adsorption quantities to BF and MB were 295 mg[#x000B7]g^[#x02212]1 and 528 mg[#x000B7]g^[#x02212]1, respectively. The equilibrium data fitted the Langmuir isotherm and the adsorption kinetics data followed the pseudo-second-order model. Adsorption processes were endothermic, entropy gained, and spontaneous in nature within 288-308 K.     

Salt Effects on the Recovery of Phenol by Liquid‐Liquid Extraction with Cyanex 923

Abstract

In this work, the effect of salt addition on the recovery of phenol from a 46 g/L aqueous solution simulating a phenolic resin plant effluent by liquid‐liquid extraction at 298 K has been studied by using an organic phase containing 0.6 M Cyanex 923 extractant in ShellSol T. Addition of sodium sulfate, potassium nitrate, and sodium chloride to the aqueous phase was tested and sodium chloride was selected. Based on the obtained results, a study of phenol recovery process was undergone by taking advantage of the salting‐out effect. Equilibrium curves are presented for liquid‐liquid extraction with and without salt addition to the aqueous phase. An integrated process involving salting‐out and liquid‐liquid extraction was proposed. The stripping concentrates can be reused for phenolic resin production.     

Enhancement of Lipase-catalyzed Synthesis of Caffeic Acid Phenethyl Ester in Ionic Liquid with DMSO Co-solvent☆

Caffeic acid phenethyl ester (CAPE) is a natural and rare ingredient with several biological activities, but its indus-trial production using lipase-catalyzed esterification of caffeic acid (CA) and 2-...     

Air filter media functionalized with β-Cyclodextrin for efficient adsorption of volatile organic compounds

Respiratory air filter media invariably comprise a nonwoven textile fabric. The limitation of the existing fibrous air filter medium is negligible protection against hazardous volatile organic compounds (VOCs). In this study, the filter media was cross-linked with β-Cyclodextrin for the surface functionalization. The VOC adsorption performance of the functional fabric was explored for styrene, benzene, and formaldehyde and also compared with a commercial nonwoven face mask. The functionalized fabric performed much better than commercial masks with adsorption capabilities of 18.80 μg mg⁻¹ (for xylene), 14.75 μg mg⁻¹ (for benzene), and 0.06 μg mg⁻¹ (for formaldehyde). Further, the cross-linking did not affect the air permeability (204 cm³ cm⁻² s⁻¹) thus showing no resistance to breathing. β-Cyclodextrin functionalized textiles can be promising respiratory air filter media having the potential to capture a variety of VOCs yet remain breathable.     

Extraction of Parabens from Water Samples Using Cloud Point Extraction with a Non-Ionic Surfactant with β-Cyclodextrin as Modifier

A cloud point extraction process using a silicone non-ionic surfactant to extract selected parabens compounds from water samples was investigated using reversed phase high performance liquid chromatography. The cloud point extraction process, in the presence of β-cyclodextrin (β-CD) as a modifier, is a new extraction process which was optimized with five parameters, i.e. salt concentration, pH of the solution, temperature, surfactant concentration and β-CD concentration. The developed method with the β-CD modifier results in an excellent performance on detection of parabens from water samples with limits of detection in the range of 0.017–0.043 μg/L and percentage recoveries from 90.5 to 98.9 %.     

New Alkylation Route of Benzene with Ethylene Catalyzed by [bmim]Cl/FeCl_3 Ionic Liquid

Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H and the route of reaction initiated the alkylation of benzene with ethylene catalyzed by [bmim]Cl/FeCl3 ionic liquid. The fact that dewatered ionic liquids have catalytic activity for the alkylation of benzene with ethylene suggests that there exists a new catalytic route. The distinctly Bronsted acid properties of 2-H in [bmim]Cl were found through FT-IR and HNMR     

Inclusion complexes of eucalyptus essential oil with β-cyclodextrin: preparation,characterization and controlled release

In this study, eucalyptus essential oil (EEO) was encapsulated into β-cyclodextrin (β-CD) by saturated aqueous solution method. The success of EEO encapsulation was confirmed by laser light scatting, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimeter and thermogravimetric analysis. Releasing characteristics experiments were carried out at various temperatures, relative humidity (RH), storage time and high temperature stability test. Release kinetics of EEO from the inclusion complexes was investigated by zero-order kinetics, first-order kinetics and Avrami’s equation. The result showed that the release model of EEO from inclusion complexes fitted better for Avrami’s equation. Kinetics analysis based on the Avrami’s equation revealed that the release of EEO was accelerated with the increases of RH and temperature. For storage time treatment, the volatilization of EEO was significantly inhibited after encapsulation. High temperature stability test further revealed that EEO was protected after having been encapsulated into β-CD. For all treatments, the release parameter n was between 0.5 and 1.0, which presenting a diffusion-limited and first-order mode. These results indicated that encapsulation enhanced the stability and prolonged the acting time of EEO, and the release rate of EEO can also be passively controlled by the ambient temperature, humidity and storage time.