Dimethyl Sulfoxide Water Research Articles

Thermodynamic Study of Poly(vinyl pyrrolidone) in Water/Dimethyl Sulfoxide Solutions by Viscometry

In this work, the intrinsic viscosities of poly(vinyl pyrrolidone) with a molar mass of 58 kg⋅mol−1 were measured in water–dimethyl sulfoxide solutions at temperatures from (298.15 to 318.15) K. The expansion factors of the polymer chains were calculated from the intrinsic viscosity data. The thermodynamic parameters (entropy of dilution parameter, the heat of dilution parameter, theta temperature, polymer–solvent interaction parameter and second osmotic virial coefficient) were derived by the temperature dependence of the polymer chain expansion factor. The thermodynamic parameters indicate that mixtures of water/dimethyl sulfoxide become poorer solvents for poly(vinyl pyrrolidone) as the temperature is increased. Also, the thermodynamic parameters indicate that water/dimethyl sulfoxide mixtures become better solvents for poly(vinyl pyrrolidone) by increasing the volume fractions of dimethyl sulfoxide.

Features of light scattering in aqueous solutions of dimethyl sulfoxide

The water-dimethyl sulfoxide (DMSO) system was studied by means of static light scattering in the concentration range of 0 to 60 mol % DMSO at 20 and 50°C. In the concentration range of 10 mol % DMSO, an abnormal maximum of scattered light was detected, the intensity of which decreases with an increase of temperature. The formation of this maximum is related to hydrophobic effects in the system under study and the existence of an unattainable critical point of delayering. Temperature inversion of light scattering intensity was detected at ∼14 mol % DMSO; at higher concentrations of DMSO, the intensity at 50°C is notably higher than at 20°C (due to the increase in the concentration’s degree of fluctuation upon an increase in temperature); at 60 mol % DMSO, intensities of scattered light at 20 and 50°C almost coincide. The apparent molar volumes of DMSO in solutions were calculated from the published data on density in the temperature range of 5 to 50°C. The minima of these values from 10 to 15 mol % DMSO (i.e., in the range of the abnormal maximum of scattered light) were obtained. The manifestation of hydrophobic effects in aqueous solutions of amphiphilic molecules is explained using the example of the DMSO-H2O system.

One-pot synthesis of 5-hydroxymethylfurfural directly from starch over [formula omitted]/ZrO2–Al2O3 solid catalyst

The synthesis of 5-hydroxymethylfurfural (HMF) directly from starch was studied in dimethyl sulfoxide–water. The effects of catalyst variation, reaction time, water content, catalyst loading and temperature on the reaction were investigated. The SO42-/ZrO2–Al2O3 catalyst was found to act as a bifunctional catalyst with high activity for both hydrolysis and dehydration of starch. HMF yield of 55% was obtained after 6h at 423K for the reaction of starch (the molar ratio of water to glucose in starch is 44/1) over the SO42-/ZrO2–Al2O3 catalyst, which bears high acidity and moderate basicity with Zr/Al molar ratio of 1:1.

Thermosolvatochromism of Nitrospiropyran and Merocyanine Free and Bound to Cyclodextrin

The thermosolvatochromism of nitrospiropyran free and bound to cyclodextrin was studied in dimethylsulfoxide (DMSO)-water binary solvent systems. Spiropyran was interconverted to merocyanine by heating the sample to 55 °C. The merocyanine (MC) was converted back to spiropyran (SP) either by cooling the sample to room temperature or irradiating the sample with a visible light emitting diode. Steady state absorption spectra of SP and MC samples in the free state and bound to cyclodextrin were obtained in several DMSO-water binary solutions. Emission spectra of MC both free and cyclodextrin-bound were also acquired. Blue-shifted absorption and emission spectra of the studied molecules with increasing solvent polarity suggest that the dipole moments of free and bound merocyanines are higher in the ground state compared to the excited state. Merocyanine dipole moments in the ground and excited states were determined using thermosolvatochromism measurements and the Lippert-Mataga, Bakhshiev, and Kawski-Chamma-Viallet polarity functions. A large change in the dipole moment (ca. 16 D) of the merocyanine in aqueous DMSO was obtained upon electronic excitation, S(1) ← S(0). Analysis of the merocyanine Stokes' shifts as a function of solvent polarity indicates that both general solvent effects and specific solvent effects are present in all systems studied. These findings reveal that merocyanine could be utilized as a polarity sensor for DMSO-water binary solutions.

Dependence of enthalpies of formation of the Cu2+ complexes with glycinate ions on the composition of water—dimethylsulfoxide solvent

Enthalpies of the complexing reactions of copper (II) with glycinate ions in mixtures of water with dimethylsulfoxide (DMSO) containing up to 0.9 mole parts of organic component (298 K) were obtained using a titration calorimeter. It was established that upon an increase in the DMSO content, the exothermicity of complexing increases at the first and second steps of the coordination. The obtained results were analyzed from the viewpoint of the solvation approach, based on the thermodynamic characterization of all reagents. It was shown that the main origin of the increase in the exothermicity of the complexing reactions is a weakening of ligand solvation when the DMSO concentration increases.

Chain structures of glucans from Lentinus edodes and their effects on NO production from RAW 264.7 macrophages

Abstract Four glucans (LNT-H, LNT-S, LNT-E, and LNT-B) were successively isolated from the fruiting bodies of Lentinus edodes by hot-water, sonication, enzyme, and NaOH. The chemical structures were characterized by GC, FTIR, and 13 C NMR, which demonstrated that the four samples are (1 → 3)-β- d -glucans with (1 → 6)-glucopyranoside side groups having different molecular weight. The results of viscometry and atomic force microscopy (AFM) proved that LNT-H, LNT-S, LNT-E, and LNT-B exist as stiff triple helices in water and random coil in dimethyl sulfoxide (DMSO). The morphology of the original triple helix was almost dominated by linear shape, but the renatured LNT-B contains some branched structures in AFM image. Among the four glucans, LNT-H, LNT-E, and LNT-B are clearly contaminated by endotoxin, while LNT-S significantly exhibits nitric oxide (NO) inhibition effect in LPS-stimulated RAW 264.7 macrophages in a dose-dependent manner. Therefore, LNT-S is probably used as a promising molecule which can be helpful to the diseases associated with NO overproduction. This is the first primary report dealing with the suppression of LPS-induced NO from macrophage RAW 264.7 cells by Lentinan.

Distribution of dissolved and particulate dimethylsulfoxide in the East China Sea in winter

The concentrations of particulate and dissolved dimethylsulfoxide (DMSOp, DMSOd) in the surface water of the East China Sea (ECS) in December 2009 were measured for the first time. The concentrations of DMSOp and DMSOd ranged from 2.4 to 80.0 nmol L −1 and from 3.2 to 357.0 nmol L −1 with average values of 21.3 nmol L −1 and 61.9 nmol L −1, respectively. The distribution of DMSOd was obviously influenced by the Yangtze River, with high concentrations appearing around the mouth of it. DMSOd represented the main methylated sulfur compound and dominated over dimethylsulfide (DMS) and dissolved dimethylsulfoniopropionate (DMSPd) by 1–2 orders of magnitude. The distribution of DMSOp did not show the same pattern as that of DMSOd. The concentrations of DMSOp increased offshore in the northeast ECS due to the change of phytoplankton species coupled to the increasing temperature, while in the southwest ECS the concentrations of DMSOp decreased offshore due to the poor DMSO-producers in the open sea. A weak positive correlation was observed between DMSOd and DMS in the whole study area. In addition, a significant relationship between DMSOp/Chl-a and temperature in the northeast ECS as well as a negative significant relationship between DMSOp and particulate DMSP in the southwest ECS was found. However, no relationship was observed between DMSOp and the environmental factors such as chlorophyll a, temperature and salinity. The vertical profiles of DMSOd in the study area were characterized by a maximum at depth from 2 to 25 m, while the DMSOp concentrations were characterized by a maximum at the bottom. Both DMSOd and DMSOp concentrations exhibited obvious diurnal variations with the maxima 7.4 and 2.4 times higher than the minima, respectively.

Reaction of Superoxide Radical with Quinone Molecules

When the superoxide radical O(2)(•-) is generated on reaction of KO(2) with water in dimethyl sulfoxide, the decay of the radical is dramatically accelerated by inclusion of quinones in the reaction mix. For quinones with no or short hydrophobic tails, the radical product is a semiquinone at much lower yield, likely indicating reduction of quinone by superoxide and loss of most of the semiquinone product by disproportionation. In the presence of ubiquinone-10, a different species (I) is generated, which has the EPR spectrum of superoxide radical. However, pulsed EPR shows spin interaction with protons in fully deuterated solvent, indicating close proximity to the ubinquinone-10. We discuss the nature of species I, and possible roles in the physiological reactions through which ubisemiquinone generates superoxide by reduction of O(2) through bypass reactions in electron transfer chains.

Constants of acid-base equilibria of glycylglycine in water-dimethyl sulfoxide solutions at 298 K

Constants of acid-base equilibria of glycylglycine were obtained by potentiometry at a temperature of 298 K and an ionic strength of 0.1 M (NaClO4) in water-dimethyl sulfoxide solutions. It was determined that upon an increase in the content of the organic component in solution, the dissociation constant of the glycylglycinium ion declines stepwise. It was concluded that the pK of the dissociation of glycylglycine versus the composition of a mixed solvent is of a critical character with a minimum in the water-organic solvent composition range of 0.1 to 0.3 molar fractions of DMSO. It is suggested that upon an increase in the concentration of DMSO, the zwitter-ion form of glycylglycine transitions to the molecular form.

Interactions of potassium fluoride with coexistent components in water–dimethyl sulfoxide mixed solvent at different temperatures

Apparent molal volumes (Vφ), apparent molal compressibilities (Kφ) and viscosity A and B-coefficients of potassium fluoride in aqueous solutions of dimethyl sulfoxide (DMSO), have been evaluated at T=303.15, 308.15, 313.15 and 318.15K from density, velocity and viscosity data, respectively. The standard partial molal volumes (Vφ0), standard partial molal volumes of transfer (ΔVφ0), standard partial molal compressibilities (Kφ0) and standard partial molal compressibilities of transfer (ΔKφ0) have been determined and interpreted in terms of solute–solvent interactions. Hepler's coefficient (∂2Vφ0/∂T2) and variation of B coefficient with temperature (dB/dT) have been interpreted in terms of the structure-making/structure-breaking effects of potassium fluoride in the mixture.

Problems of solubility of hydrolysis lignin

Interaction of hydrolysis lignin with polyacrylonitrile in water-dimethyl sulfoxide solution in the presence of an activator was studied, and the properties of the products were examined.

The influence of solvation on the formation of Ag+ complexes with 18-crown-6 ether in water-dimethyl sulfoxide solvents

The Gibbs energies of transfer of 18-crown-6 ether from water into water-dimethyl sulfoxide (DMSO) solvents (χDMSO = 0.0–0.97 mole fractions) at 298.15 K were determined by the interphase distribution method. Changes in the composition of the aqueous-organic solvent did not cause noticeable changes in the stability of 18-crown-6 ether solvato complexes. Reagent solvation contributions to shifts of complex formation equilibrium between silver(I) and 18-crown-6 ether when water was replaced with dimethyl sulfoxide were analyzed.

Copolymerization of sodium 2-acrylamido-2-methylpropanesulfonate with sodium acrylate in water-dimethyl sulfoxide solutions

The solvent effect on the kinetic features of the synthesis and molecular characteristics of the copolymers in homogeneous radical copolymerization of sodium 2-acrylamido-2-methylpropanesulfonate with sodium acrylate in water and water-dimethyl sulfoxide mixtures (75: 25, 50: 50, 25: 75) at pH 9 and 60°C in the presence of potassium persulfate was studied

Spontaneous Cu(I)Br–PMDETA‐mediated polymerization of isobornyl methacrylate in heterogeneous aqueous medium at ambient temperature

AbstractIsobornyl methacrylate (IBMA), a bulky hydrophobic methacrylate, undergoes very fast polymerization, in bulk, with Cu(I)Br/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA)/ethyl‐2‐bromoisobutyrate system, at ambient temperature. IBMA also undergoes a spontaneous initiator‐free polymerization, at ambient temperature, with Cu(I)Br/PMDETA catalytic system in dimethyl sulfoxide–water mixtures. The rate of the polymerization is seen to increase with the water content up to 80 mol % of water. A possible intervention of air in initiation is proposed. The active Cu(0) formed by the disproportionation of Cu(I) species in aqueous medium probably plays a vital role for a possible air‐initiation of IBMA via single electron transfer‐living radical polymerization (SET‐LRP) mechanism. A high tolerance level to water under SET‐LRP conditions is demonstrated. The poly(IBMA) samples obtained exhibit low molecular weight distributions (1.1–1.3). Similar behavior was not observed with other common methacrylates such as methyl methacrylate, t‐butyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

The thermodynamic properties of solutions of L-ascorbic acid in dimethyl sulfoxide and water-dimethyl sulfoxide mixtures

Solutions of L-ascorbic acid (AA) in dimethyl sulfoxide (DMSO) and DMSO-water mixtures were studied by the densitometry, surface tension, and calorimetry methods. The apparent and partial molar volumes of AA in solutions at 298.15 K were calculated. Surface tension insignificantly increased as the concentration of AA in DMSO grew. The enthalpies of solution of AA in the solvents and the enthalpies of transfer of AA from water into DMSO and DMSO-water mixed solvents were calculated. The results obtained were explained by the existence of H-bonds between AA and DMSO molecules.

Solvent effect in monoclinic to hexagonal phase transformation in LaPO 4:RE (RE=Dy 3+, Sm 3+) nanoparticles: Photoluminescence study

Nanosized phosphor materials, LaPO 4:RE (RE=Dy 3+, Sm 3+) have been synthesized using water, dimethyl sulfoxide (DMSO), ethylene glycol (EG) and mixed solvents at a relatively low temperature of 150 °C. X-ray diffraction (XRD) study reveals that as-prepared nanoparticles prepared in DMSO and EG are well crystalline and correspond to monoclinic phase. In the mixed water–DMSO or water–EG solvents, XRD patterns are in good agreement with hexagonal phase, but transformed to monoclinic phase at higher temperature of 900 °C. TEM images show well-dispersed and rice-shaped nanoparticles of diameter 5–10 nm, length of 13–37 nm for Dy 3+-doped LaPO 4 and diameter of 25–35 nm, length of 73–82 nm for Sm 3+-doped LaPO 4. Dy 3+-doped LaPO 4 shows two prominent emission peaks at 480 and 572 nm corresponding to 4F 9/2→ 6H 15/2 (magnetic dipole) and 4F 9/2→ 6H 13/2 (electric dipole) transitions, respectively. Similarly, for Sm 3+-doped LaPO 4, three prominent emission peaks at 561, 597 and 641 nm were observed corresponding to 4G 5/2→ 6H 5/2, 4G 5/2→ 6H 7/2 (magnetic dipole) and 4G 5/2→ 6H 9/2 (electric dipole) transitions, respectively. The luminescence intensity of the sample prepared in EG is more than that of DMSO or mixed solvents. Enhancement of luminescence is also observed after heat-treatment at 900 °C due to removal of quencher such as water, organic moiety and surface defects/dangling bonds. The samples are re-dispersible in polar solvent and can be incorporated in polymer film.

Hypersensitive Luminescence of Eu3+ in Dimethyl Sulfoxide As a New Probing for Water Measurement

Dimethyl sulfoxide (DMSO) is a well-known organic solvent that can be used for biological applications. DMSO is miscible with water, and it is very common that the two solvents are mixed for some applications. It is important to detect water in DMSO, and this has been done using the luminescence decay lifetimes from Eu(3+) ions. We observed that the emissions of Eu(3+) in DMSO are very strong and very sensitive to water. The emission band from the (5)D(0) → (7)F(2) transition has two peaks at 613 and 617 nm, respectively, and these two peaks change in the opposite ways when water is added into DMSO. The intensity ratio of the two peaks follows nearly perfect linear dependence on the water concentration added in DMSO. This linear relationship provides a new and convenient method for water measurement in DMSO.

Fluorescent analysis of the structural changes of human serum albumin induced by low temperatures in water-dimethyl sulfoxide solutions

Structural changes in human serum albumin (HSA) induced by low temperatures in water-dimethyl sulfoxide (DMSO) solutions were studied by fluorescent spectroscopy. The emission, synchronous, and isopotential synchronous spectra (3D spectra) of the HSA were analyzed. It was shown that protein does not undergo drastic structural changes in the fast freezing/defrosting mode in solutions of up to 20% DMSO but becomes more compact.

Screening of medicinal plants for antibacterial principles against β-lactam resistant strains

Sir, In the present work, screening of different plants used in Indian folk medicine was carried out for the detection of antibacterial principles against β-lactam resistant bacterial strains, which may be useful as new drugs to combat deadly infections. [1,2] Twenty-nine plants were tested for their antibacterial activities. The collected plants were washed and shade dried. Twenty grams of the plant material was macerated and extracted with hexane, diethyl ether, methanol and water using a Soxhlet apparatus, based on their polarity. The dry fractions were made into a suspension using 10% dimethylsulfoxide (DMSO) in distilled water. The concentration of the extracts was adjusted to 1 mg/mL in each case. The antibacterial properties of the plant extracts were evaluated by employing the disc diffusion method. Evaluation of the synergistic effect of the plant extracts with β-lactam antibiotics was done according to the method of Muroi and Kubo. [3] The diethyl ether extracts of Holoptelea integrifolia, Pongamea pinnata, Spondias dulci and methanol extract of Syzygium samarengense showed good synergistic effects with amoxicillin and ampicillin against Staphylococcus aureus in disc diffusion method. They were further fractionated by silica gel chromatography to identify the antibacterial compound. The structure of the compounds in the active fractions was elucidated by spectroscopic analysis methods such as gas chromatography–mass spectrometry (GC–MS), Fourier Transform Infrared Spectroscopy (FTIR) and 1H nuclear magnetic resonance (NMR) analysis [Table 1]. The diethyl ether extracts exhibited a higher degree of antimicrobial activity compared to methanol extract. The extracts of H. integrifolia, P. pinnata, S. dulci and S. samarengense showed an increase in the growth inhibition zone in the presence of amoxicillin. This indicates that the plants contain compounds which can enhance the effect of amoxicillin. Other plant extracts did not show any noticeable synergistic effect. The synergistic effect of plant extracts against resistant bacterial strains may lead to a new choice for the treatment of infectious diseases. [4] The active principle can be used along with commonly used antibiotics. Data from the literature as well as from our studies reveal a great potential of plants in this direction.

The Influence of Casting Machine Speed in Cellulose Acetate Membrane Preparation

Membranes are being increasingly used as a valuable separation tool in laboratory as well as in industrial processes. Continual development of new membrane materials is crucial to sustain and expand the growing interest in this technology and modern polymer chemistry is highly proficient in tailoring polymers with desired properties such as increased mechanical, thermal and chemical stability. Cellulose acetate (CA) is one of the membrane polymers that has been used for aqueous based separation and used as both reverses osmosis (RO) and ultrafiltration (UF) membranes. This paper presents investigation of influence of casting machine speed in membrane preparation. CA is used in this study. That was CA-398-30 with average acetyl content 39.8 wt %. Non solvent used is water and the solvent is 99.7 % organic Dimethyl Sulfoxide (DMSO). The homogenous CA/DMSO solutions were prepared by dissolving CA in DMSO solvent. The CA concentration were varied 13 and 16 % while casting solution speed were varied from 20 to 80 mm/sec with distance cutting machine were fixed at 14 cm. In addition, non solvent in coagulation bath also were varied by 100 % water and 10 % DMSO in water. The results of this experiment describe effect of casting machine speed to water permeability. The effect of CA concentration to water permeability shows the adversative result between 13 and 16 % CA in 100 non solvent water. The similar result also observed in 10 % DMSO in water.