Glycol System Research Articles

Optical studies of acefylline piperazine, chlorpheniramine maleate, thiamine hydrochloride in aqueous, aqueous methanol and aqueous ethylene glycol systems

Refractive index, FTIR and Uv–vis absorption study of acefylline piperazine, chlorpheniramine maleate, thiamine hydrochloride was done to investigate the solute-solvent interactions. The interaction of drugs (AP, CPM, TAD) studied in aqueous, aqueous methanol and aqueous ethylene glycol systems at 303 K. Specific refraction, Molar refraction and polarizability of drugs in aqueous and aqueous alcoholic systems was calculated by using Lorentz-Lorentz equation. FTIR study of drugs in aqueous and aqueous alcoholic systems was undertaken to analyze the compatibility of drugs in studied systems. The UV–vis absorption study has also been done to interpret the interaction patterns occurring in drugs and solvent systems.

Deep Red emitting dicyanovinylene isophorone based chromophores: Combined synthesis, optical properties, viscosity sensitivity, and DFT studies

Deep red emitting dicyanovinylene isophorone based dyes are synthesized and studied for photophysical properties, viscosity sensitivity, and DFT. The dyes consist of Carbazole and Triphenylamine donor and thiophene spacer together with one auxiliary accepter, –CN leads to deep red emission towards the NIR region (∼600−700 nm) in polar solvent media. All dyes show good emission solvatochromism with an increase in solvent polarity. The dyes show intramolecular (ICT) as well as “Twisted Intramolecular Charge Transfer (TICT)” which is reinforced by Lippert Mataga, MacRae, Weller, and Rettig plots. Viscosity induced emission enhancement study in ethanol/polyethylene glycol (PEG 400) system shows 4.34–4.85 folds increases emission intensity. ICT is supported by Frontier Molecular Orbital (FMO) diagram and bandgap energy. The observed experimental findings are also correlated with the computed values using “Density Functional Theory (DFT)”. The magnitudes of “first order hyperpolarizability”(β0) are 500−1000 × 10−30.e.s.u. while those of the “second order hyperpolarizability”(γ) are 3000−8300 × 10-36 e.s.u. Hence they can act as very good NLOphores. Mulliken Hush analysis and Natural Bond Orbital (NBO) analysis were used to support charge transfer characteristics.

Liquid-liquid equilibria of aqueous two-phase systems made of polyethylene glycol and gelatin systems and their application in emulsion formation

Water-in-water (W/W) emulsion is an interesting template for microentrapment of hydrophilic compounds due to biocompatible nature of its aqueous media. W/W emulsification can be established from a destabilised aqueous two-phase system (ATPS). In this study, binodal data of ATPSs comprising polyethylene glycol (PEG) and gelatin were generated. Binodal curves of PEG + gelatin + water systems were successfully correlated using non-linear empirical Merchuk equation, and the tie lines were constructed using lever-arm rule. The effects of temperature, type of gelatin, and molecular weight of PEG on the binodal curves were evaluated. Notably, a higher molecular weight of PEG decreased the concentration of gelatin required for two-phase formation. ATPSs made of gelatin bovine has a larger biphasic region than that of gelatin porcine. Gelatin microgel was successfully synthesized from the PEG + gelatin emulsion system via rapid cooling of the dispersed phase of gelatin. The size of gelatin microgel was reduced by a higher stirring speed, while a temperature as high as 333.15 K increased the size distribution of gelatin microgel. Lastly, the microentrapment of model protein, green fluorescent protein, was demonstrated. PEG/Gelatin system holds good potential for food engineering and delivery system.

Optimization of Aqueous Two Phase Extraction of Proteins from Litopenaeus Vannamei Waste by Response Surface Methodology Coupled Multi-Objective Genetic Algorithm

Abstract Waste generated from industrial processing of seafood is an enormous source of commercially valuable proteins. One among the underutilized seafood waste is shrimp waste, which primarily consists of head and carapace. Litopenaeus vannamei (L. vannamei) is the widely cultivated shrimp in Asia and contributes to 90 % of aggregate shrimp production in the world. This work was focused on extraction as well as purification of value-added proteins from L. vannamei waste in a single step aqueous two phase system (ATPS). Polyethylene glycol (PEG) and trisodium citrate system were chosen for the ATPS owing to their adequate partitioning and less toxic nature. Response surface methodology (RSM) was implemented for the optimization of independent process variables such as PEG molecular weight (2000 to 6000), pH (6 to 8) and temperature (25 to 45 °C). The results obtained from RSM were further validated using a Multi-objective genetic algorithm (MGA). At the optimized condition of PEG molecular weight 2000, pH 8 and temperature 35 °C, maximum partition coefficient and protein yield were found to be 2.79 and 92.37 %, respectively. Thus, L. vannamei waste was proved to be rich in proteins, which could be processed industrially through cost-effective non-polluting ATPS extraction, and RSM coupled MGA could be a potential tool for such process optimization.

Vapour-liquid equilibria in water + poly(ethylene glycol) systems: New experiments and cumulative thermodynamic processing of all data

Dependences of total pressure on the composition of water + poly(ethylene glycol) systems were measured with both the ebulliometric and static method. New data on vapour-liquid equilibria cover the temperature range 303.15–363.15 K and the range of the weight fraction of solvent 0.5–1.0 for polymers of nominal molecular weight 1000, 3000, and 6000 g mol−1. These data together with those determined earlier were correlated using the UNIQUAC free-volume (FV) model to be consistent with previous studies. In addition, all available literature data on this system were processed in the same way. As a result, the obtained average deviations were used as indicators of data quality. Average deviation of experimental and calculated solvent activity was about 0.0004 for all our data. The evaluated adjustable parameters were proportional to molecular weight, which ensures reliable interpolation and even extrapolation beyond the investigated temperature and molecular weight ranges.

Experimental and Thermodynamic Modeling of Quaternary Aqueous Two-Phase System of Poly Ethylene Glycol, Sodium Tartrate, Water and Penicillin G

In present study, the liquid–liquid equilibrium of the quaternary system of polyethylene glycol (PEG) (with molar masses of 1000, 2000, 6000, and 8000 g·mol−1), sodium tartrate salt, Penicillin G and water at 298 K were investigated. The partitioning of Penicillin G between two aqueous phases was also reported. The extended non random two liquid (NRTL) and extended Universal Quasi Chemical (UNIQUAC) models were used to correlate the experimental equilibrium data. The parameters of these activity coefficient models were optimized for the investigated systems. The results show that the polymer molar mass has a dominant effect on the partition coefficient of Penicillin G. Also, results of both thermodynamic models were very satisfactory and satisfactory predicted the equilibrium concentrations of the components in ATPS. Comparison of the absolute average deviation of the two models shows that the extended UNIQUAC model was superior to the extended NRTL model for correlation and interpolation of phase equilibrium data.

Influence of polyethylene glycol and surfactant mixed system on the rate of alkaline hydrolysis of benzocaine

The rate of alkaline hydrolysis of benzocaine has been studied spectrophotometrically in the presence of polyethylene glycols (PEGs), surfactants (cetyltrimethylammonium bromide; CTABr and sodium dodecyl sulphate; SDS) and in the mixed media of surfactants-polysurfactants (PEGs-CTABr and PEGs-SDS). The observed values of rate constant increased linearly with the increase in [NaOH] at fixed [benzocaine] obeying the equation: kobs = k2[NaOH]. The rate constant – [CTABr] plot showed peaked behaviour whereas in case of SDS, the rate constant decreased with increase in [SDS]. The increase in the molecular weight of PEGs increased the binding tendency of PEG-CTABr system for benzocaine, in turn, an increase in inhibitory effect on the rate of hydrolysis was observed. The obtained values of the binding constant decreased with the increase in the molecular weight of PEGs in PEG-SDS mixed system. The binding constant and the values of rate constant in the surfactant, PEG-surfactant media were determined by using Pseudophase Ion Exchange (PIE) and pseudophase models.

Metal‐Free and Heterogeneous Photocatalytic Reduction of 4‐Nitroaniline by a Poly(Ethylene Glycol)‐Supported Eosin Dye under Visible‐Light Exposure

AbstractA new feasible approach for the photoreduction of a chemical pollutant, 4‐nitroaniline, to p‐phenylenediamine was developed. We highlighted the crucial roles of a polymer backbone and the atmosphere for the efficient heterogeneous reduction of 4‐nitroaniline. The novel synthesized poly(ethylene glycol)‐derived film containing immobilized eosin dye revealed a high photoreduction rate of 4‐nitroaniline. According to laser flash photolysis results the first step of this photoinduced process represents a single electron transfer from eosin radical anion to the 4‐nitroaniline to form a nitroaniline radical anion. The in‐situ electron paramagnetic resonance spin‐trapping experiments evidenced the generation of superoxide radical anion serving as catalyst in the p‐phenylenediamine production according to a photoreduction process. The main roles play by poly(ethylene glycol) matrix as efficient reducing agent and hydrogen‐donor molecule was also pointed out. A mechanism was proposed to explain the heterogeneous photoreduction of 4‐nitroaniline to p‐phenylenediamine in the presence of eosin dye‐based poly(ethylene glycol) system under air.

Experimental study on the compound system of proanthocyanidin and polyethylene glycol to prevent coal spontaneous combustion

In order to overcome the short inhibition duration of physical inhibitor, the environmentally friendly chemical inhibitors of polyethylene glycol (PEG) and proanthocyanidin (OPC) were selected to conduct the experimental study for coal spontaneous combustion prevention. Through temperature programmed experiment, electron spin resonance experiment and Fourier infrared spectroscopy experiment, it was found that for the coal sample after treated by PEG and OPC, crossing point temperature increased by 17.6 °C and 14.3 °C, free radical concentration decreased to 0.1512 Ng/1017 g−1 and 0.1178 Ng/1017 g−1, association and hydroxyl free hydroxyl groups decreased by 59.72% and 24.37%, and the stability of the COC ether bond increased by 42.71% and 18.41%, respectively, which showed the inhibition effects of both inhibitors are obvious and OPC is better. For the sample treated by OPC and PEG (ratio 1:2), crossing point temperature increased 25 °C, which indicated that the collaborative effect was remarkable. The analysis shows that PEG and OPC contain a large number of hydroxyl groups, which react with the oxide intermediate product alcohol to form ether bonds with relatively stable chemical properties, thus mitigating the rate of coal spontaneous combustion; PEG and OPC are linked by hydrogen bonds to synthesize larger hydrogen proton donors, which improved antioxidant activity. PEG is a viscous liquid, when carrying proanthocyanidin, can cover the surface of coal, isolating coal surface from oxygen, keeping moisture and cooling. The combination of the two inhibitors has significant synergistic inhibition effect, which can greatly suppress the coal spontaneous combustion.

A sensitive amperometric sensor for hydrazine based on Pt nanoparticles-reduced graphene oxide–multi-walled carbon nanotubes composite

ABSTRACTThe platinum nanoparticles-reduced graphene oxide-multi-walled carbon nanotubes composite (PtNPs-rGO-MWCNTs) has been synthesised by one-step chemical co-reduction strategy in ethylene glycol (EG) system using sodium citrate as reducing agent. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), as well as the electrochemical methods have been used for the characterisation of this composite. Benefiting from the large effective surface and good carrier function of rGO-MWCNTs, PtNPs in this nanocomposite have some excellent characteristics such as small particle size, good dispersion, as well as high electrocatalytic activity. Based on this, a new electrochemical sensor for hydrazine has been fabricated using dropping method. Under the optimum conditions, the linear range for the determination of hydrazine by amperometry at 0.20 V (vs. SCE) in phosphate buffer (pH 7.0) is from 2.0 × 10−7 mol L−1 to 2.3 × 10−3 mol L−1. The detection limit and sensitivity is 4.5 × 10−8 mol L−1 (S/N = 3) and 219.7 μA mM−1, respectively. This sensor has some attractive analytical features such as low detection limit, wide linear range, high sensitivity, as well as good stability.

Aqueous two-phase systems for cephalexin monohydrate partitioning using poly ethylene glycol and sodium tartrate dihydrate: Experimental and thermodynamic modeling

The partitioning of cephalexin monohydrate in aqueous two-phase system (ATPS) of polyethylene glycol (PEG) with different molecular weights (1000, 2000, 6000, and 8000) and sodium tartrate dihydrate salt was investigated. Equilibrium compositions of two liquid phases were obtained in each system. The experimental data were correlated using the extended NRTL and a modified UNIQUAC (UNIQUAC+DH) models by adding a Debye-Huckel term (DH) to original models for taking into account the long range forces term of activity coefficient of components. The results show that the molecular weight of the polymer has a considerable effect on the partition coefficient of cephalexin monohydrate. The comparison of results for presented models with the experimental data demonstrates that the investigated thermodynamic models can correlate the equilibrium composition very well. The extended NRTL model with AARD of 0.099 is superior to UNIQUAC+DH.

Electrochemical Behavior of Co(II) Reduction for Preparing Nanocrystalline Co Catalyst for Hydrogen Evolution Reaction from 1-ethyl-3-methylimidazolium Bisulfate and Ethylene Glycol System

The electrochemical behavior of Co(II) reduction and Co nucleation/growth process on glassy carbon (GC) electrode in 1-ethyl-3-methylimidazolium bisulfate ([EMIM]HSO4) ionic liquid (IL) and ethylene glycol (EG) system is investigated. Cyclic voltammetry (CV) measurements indicate that Co(II) reduction occurs by a one-step process, Co(II) to Co(0), and it is an irreversible reaction. The diffusion coefficient of Co(II) is 2.24 × 10−6 cm2 s−1 at 323 K in the system. Chronoamperometry measurements show that the growth/nucleation process of Co on GC electrode in [EMIM]HSO4-EG is a three-dimensional (3D) progressive nucleation at lower overpotentials and instantaneous nucleation at higher overpotentials under diffusion controlled growth process. These effects of electrodepositing potential, current density and temperature on Co coating thickness are also investigated. The Co coatings are observed by energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and X-ray diffractometer (XRD). SEM micrographs confirm that the Co coatings are relatively loose with a fibrous surface morphology. XRD pattern of the prepared coating reveals the characteristic peak of crystalline Co with a preferred orientation direction and the average size of Co grains is 11 nm. The nanocrystalline Co coating exhibits an excellent catalytic activity and stability for hydrogen evolution reaction (HER) in alkaline medium.

Codeposition of Nanocrystalline Co-Ni Catalyst Based on 1-ethyl-3-methylimidazolium Bisulfate and Ethylene Glycol System for Hydrogen Evolution Reaction

The codeposition behavior of Co(II) and Ni(II) in 1-ethyl-3-methylimidazolium bisulfate ([EMIM]HSO4) ionic liquid (IL) and ethylene glycol (EG) system is recorded using cyclic voltammetry (CV). The result indicates that the mechanism of Co-Ni codeposition is an anomalous codeposition, and both the inhibition for Ni(II) reduction and the anomalous codeposition phenomena can be improved by the increase of Co(II) concentration in the system. These Co-Ni deposits are characterized using EDS, XRD and SEM. SEM micrographs indicate that the surface morphology of Co-Ni deposits can be changed by the increase of Co content, and these deposits with many additional elongated acerose crystals, which are germinated on the spherical “nodules” surface, can be prepared. XRD pattern reveals the feature peak of crystalline Co1.2Ni2.8 with a preferred orientation direction and the average size of grains is calculated to be about 14.6 nm. Moreover, the electrocatalytic activity for hydrogen evolution reaction (HER) on the prepared Co-Ni catalyst surface is investigated using linear sweep voltammetry (LSV) and electrochemical impedance spectra (EIS). These results indicate that the obtained catalyst presents an excellent electrocatalytic activity and durability for HER with an overpotential of 139 mV at 10 mA cm−2 in 1 M KOH solution.

Enhanced cathode performance of LiFePO4/C composite by novel reaction of ethylene glycol with different carboxylic acids

Abstract In this paper, nano-scale LiFePO4/C composite was prepared by adding monocarboxylic acid (benzoic acid), dicarboxylic acid (oxalic acid) and tricarboxylic acid (citric acid) as additives in ethylene glycol. A systematic description of the impacts from the number of carboxyl groups on the morphology and electrochemical properties of LiFePO4/C composite in the ethylene glycol system was provided. And the significantly size reduction and similar morphology to uniform rice grain were observed after the surface grafting reaction of ethylene glycol with carboxylic acids on the LiFePO4/C particle surface. Furthermore, the experiments indicated regular changes in the dispersibility and electrochemical properties. The sample in which citric acid was added performed best in terms of dispersibility with the particle size of about 800 nm, and also good regarding electrochemical property with first discharge capacity of 148.13 mAh/g and coulombic efficiency of 97.97%.

Quantifying Guest-Host Dynamics in Supramolecular Assemblies to Analyze Their Robustness.

The most basic function of synthetic microenvironments for tissue engineering is to act as a physical substrate for cell attachment, migration, and proliferation, similar to the natural cell environment. Functionalization of supramolecular materials with guest compounds that display the same recognition moieties is a common strategy to introduce biofunctionality. However, besides a robust interaction with the material, a certain level of dynamics needs to be conserved for an adaptive interface toward the living environment. A balance between robust material functionalization and dynamic cell interaction needs to be met. The detailed analysis hereof using a ureido-pyrimidinone (UPy) poly(ethylene glycol) system in dilute and transient network regime is demonstrated. Monovalent and bivalent UPy-functionalized guest molecules are designed and their interaction with UPy-host fibers is evaluated. Analysis of guest interaction in the dilute state by microfluidics, and in the gel state, by fluorescence recovery after photobleaching and fluorescence resonance energy transfer is proven to be suitable to quantify the local and ensemble guest mobility. The results demonstrate that the interaction of bioactive moieties through supramolecular host-guest chemistry yields a dynamic system, which is stronger for divalent guests but risks unintended leakage in the case of functional monomeric units.

Effects of sodium chloride and sodium perchlorate on properties and partition behavior of solutes in aqueous dextran-polyethylene glycol and polyethylene glycol-sodium sulfate two-phase systems

Effects of two salt additives, NaCl and NaClO4, at the fixed concentrations of 0.215 M on the properties of aqueous two-phase systems (ATPSs) formed by dextran (Dex) and polyethylene glycol (PEG), and the effects of NaClO4 at the same concentration on the properties of ATPS formed by PEG and Na2SO4 were examined. The effects of these salt additives on partitioning of 12 small organic compounds and five proteins in the above ATPSs were studied. In each system with a given salt additive, 0.5 M sorbitol, 0.5 M sucrose, and 0.5 M and 1.5 M trimethylamine N-oxide (TMAO) were also used as additives. The results obtained were compared with those reported previously for the Dex-PEG ATPS without salt additives and PEG-Na2SO4 ATPS without salt additives and in the presence of 0.215 M NaCl. It is shown that the differences between the solvent properties of the phases in the systems formed by polymer and salt exceed those observed in the systems formed by two polymers. The three most significant solvent features of the systems are hydrophobic and electrostatic properties and hydrogen bonding donor acidity of the solvent media. Osmolyte additives were found to have a significant effect on the differences between the electrostatic properties of the phases. Analysis of the partition coefficients of 12 organic compounds and five proteins showed that the osmolyte additives may affect the partition behavior of compounds in a compound-specific manner. The relative contributions of different types of interactions of a given compound with aqueous media change in the presence of salt and osmolyte additives. Analysis of the variability ranges of partition coefficient, K, in the systems studied showed that for small organic compounds, the ranges of K-values observed in the PEG-Na2SO4 ATPSs exceed those determined in the Dex-PEG ATPSs quite significantly, whereas for proteins, the range of K-values in Dex-PEG ATPSs exceeded those in PEG-Na2SO4 ATPSs for three proteins, and were very similar for two proteins. This observation supported the notion that the ATPSs formed by two polymers are more suitable for protein analysis than those formed by a single polymer and a salt. The single polymer-salt ATPSs have an advantage for protein isolation/separation.

Corrosion behavior of zinc coating electroplated at high current from a deep eutectic solvent

A Zinc coating was electroplated in choline chloride-ethylene glycol system at high current density in atmosphere. The crystal structure, surface and cross-section morphologies, chemical elements of electroplated zinc coating were analyzed by x-ray diffraction and scanning electron microscopy with line analysis, respectively. The bending and corrosion performances were also discussed in this study. The results indicate that the zinc coating presents a highly (110) texture with small flake zinc grains stacked on the surface. The zinc coating exhibits well bonding with the copper substrate though no obvious diffusion layer was observed. The corrosion performance of zinc coating displays a combine system of the electrode process and diffusion process without passivation process.

Vapour–liquid equilibrium study of binary mixtures of aniline with isopropanol, n-butanol and ethylene glycol at the local atmospheric pressure

ABSTRACTThe present work analyses the vapour–liquid equilibrium (VLE) behaviour of the binary systems of aniline with isopropanol, n-butanol and ethylene glycol. The isobaric VLE data have been generated at the local atmospheric pressure of 96.15 kPa for all the binary systems of aniline. A dynamic type vapour–liquid circulating VLE still was used for generating the data. Calibration curves were generated using mole fraction and refractive index data for all pairs for composition measurement. The VLE data, generated in T-x,y form for all pairs, were found thermodynamically consistent through the Herington area test and the mean absolute deviation test. Activity coefficient models, Wilson, NRTL and UNIQUAC, were fitted to the data to estimate binary interaction parameters using an objective function of minimising the deviation between the experimental and the calculated total pressure and vapour composition. The experimental data were compared with the model predictions with the estimated parameters and the model predictions were found appropriate. The binary system of aniline and ethylene glycol was found to exhibit azeotropic behaviour at 0.61 mole fraction aniline and 445.1 K.

Viscosities of diethylene glycol (DEG) + 2-amino-2-methyl-1-propanol (AMP) + water

In this study, the viscosities (η) of the aqueous mixed-solvent system of diethylene glycol (DEG) and 2-amino-2-methyl-1-propanol (AMP) were investigated at normal atmospheric pressure over the range of temperature of 303.15 - 343.15 K and across varying component mole fractions range [0.02 to 0.60 for DEG (x1 ), 0.02 to 0.60 for AMP (x2 ), and 0.20 to 0.80 for H2O (x3 )]. The calculated properties were fitted to a modified equation originally proposed by Grunberg and Nissan for the viscosity of liquid mixtures to correlate temperature and composition dependency of the measured property. In comparison to literature values, the uncertainty of the kinematic viscosities was approximated to be + 1.0 %, and that the correlations used satisfactorily represent the effects of temperature and composition on the viscosities of the considered mixed-solvent system as shown by the low overall average absolute deviations obtained in the calculations. The properties obtained and reported in this work are, in general, of adequate correctness for most engineering-design calculations, such as the design of absorption process for carbon dioxide capture using mixed-solvents as absorbents.

Structure Breaking/Making Property of Acefylline Piperazine in Aqueous, Aqueous Methanol, and Aqueous Ethylene Glycol Systems

Densities of acefylline piperazine (AP) in aqueous, aqueous methanol, and aqueous ethylene glycol (10% v/v) systems are determined in the concentration range 0.04-0.14±0.001 mol/dm3 at different temperatures (298.15-318.15 K) with the interval of 5 K. The apparent molar volume (φv), the partial molar volume $$(\phi_v^0)$$ , and the ion-ion interaction parameter (Sv) are calculated using the Masson equation. Partial molar expansibilities $$(\phi_E^0)$$ , which indicate the presence or absence of the caging or packing effect, are also evaluated and discussed. The results are interpreted in terms of solute-solvent and solute-solute interactions of AP in aqueous, aqueous methanol, and aqueous ethylene glycol systems. The structure-breaking and structure-making properties of AP are inferred by the sign of Hepler′s criterion $$(\partial^2\phi_v^0/\partial{T}^2)_p$$ , i.e. the second derivative of the partial molar volume with respect to the temperature at the constant pressure.