Acetone Ratio Research Articles

(Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

On this paper, experimental (liquid+liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water+1-propanol+β-citronellol) and (water+acetone+β-citronellol) were determined with a tie-line method at T=(283.15, 298.15, and 313.15±0.02)K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid+liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models.

Fabrication of a dual-layer (CA/PVDF) hollow fiber membrane for RO concentrate treatment

In this study, a dual-layer hollow fiber nanofiltration (NF) membrane was fabricated with an inner layer of poly(vinylidene fluoride) (PVDF) via thermally induced phase separation (TIPS), and an outer layer of cellulose diacetate (CA) via non-solvent induced phase separation (NIPS). The intermediate-treatment using dimethyl formamide (DMSO) between the two layers increased the porosity of inside surface of outer layer. The nanopore of the outside surface of outer layer was molecularly designed by controlling the dope solution composition, i.e., the polymer concentration, the co-solvent additive (acetone) ratio and TiO2 nanoparticle loading. By increasing the acetone ratio and TiO2 nanoparticle loading, the pore size became narrower and the pore size exhibited dominate effects on both filtration and separation performances. Moreover, biofouling and bacterial growth on the membrane were reduced by increasing the TiO2 nanoparticle loading. The dual-layer (CA/PVDF) hollow fiber membranes had high strengths larger than 8MPa, Na2SO4 rejections of 90–95% and pure water permeabilities of 1–4Lm−2h−1bar−1. The feasibility of treating RO concentrates by the resultant membrane was proven by the effective removal of total organic compounds (>90%) and low rejection of total dissolved salts (<60%).

Retraction: Acid-Catalyzed Aquation of Ni(II)-Hydrazone Complexes: Kinetics and Solvent Effect

Complexes of the type [Ni(L)(H2O)]Cl2·nH2O, where L = 2-pyridyl-3-isatinbishydrazone ligands, have been synthesized and characterized on the bases of elemental analysis, molar conductance, IR, electronic spectra, and thermal analysis (TGA and DTA). Acid-catalyzed aquation of the Ni(II) isatin-bishydrazone complexes was followed spectrophotometrically in various water–methanol and water–acetone mixtures at temperature 298 K. Kinetic behavior of the acid aquation is a linear rate law, indicating that the acid-catalyzed aquation of these complexes in water–methanol and water–acetone mixtures follows a rate law with kobs = k2[H+]. The effect of the mole fraction of the ganic solvent, i.e., methanol and acetone, on the acid aquation has been analyzed; the decrease in the rate constant values with increasing of the methanol or acetone ratios is attributable to the effect of the co-organic solvent on the initial states of the acid aquation by the destabilization of the H+ ion.

Effect of Acetone on Physical Properties of PES Membrane

In the present study, polyethersulfone (PES) dope solution were prepared from mixtures of two solvents containing dimethylformamide (DMF) as core solvent, and acetone as co-solvent (CS), deionized water was used as coagulant bath. The amount of PES was kept at 20 wt% and the weight ratios of acetone were varied 20-24 wt.% to DMF and the dope solutions were prepared under closed heating system Results revealed the complete miscibility of PES with the fixed mixture of acetone and DMF under atmospheric pressure. The relationships between degree of adsorption, relative water absorption, were investigated. The results revealed that the interaction of DMF and acetone is strongest when their mole ratio is unity, which exhibit the phenomenon of true cosolvency for PES membrane. Keywords: polyethersulfone, solvent mixture, characterization.

Influence of corona discharge on the ozone budget in the tropical free troposphere: a case study of deep convection during GABRIEL

Abstract. Convective redistribution of ozone and its precursors between the boundary layer (BL) and the free troposphere (FT) influences photochemistry, in particular in the middle and upper troposphere (UT). We present a case study of convective transport during the GABRIEL campaign over the tropical rain forest in Suriname in October 2005. During one measurement flight the inflow and outflow regions of a cumulonimbus cloud (Cb) have been characterized. We identified a distinct layer between 9 and 11 km altitude with enhanced mixing ratios of CO, O3, HOx, acetone and acetonitrile. The elevated O3 contradicts the expectation that convective transport brings low-ozone air from the boundary layer to the outflow region. Entrainment of ozone-rich air is estimated to account for 62% (range: 33–91%) of the observed O3. Ozone is enhanced by only 5–6% by photochemical production in the outflow due to enhanced NO from lightning, based on model calculations using observations including the first reported HOx measurements over the tropical rainforest. The "excess" ozone in the outflow is most probably due to direct production by corona discharge associated with lightning. We deduce a production rate of 5.12 × 1028 molecules O3 flash−1 (range: 9.89 × 1026–9.82 × 1028 molecules O3 flash−1), which is at the upper limit of the range reported previously.

Chemical Synthesis, Spectral Characterization and Antimicrobial Studies on Complexes of Ni(II), Cu(II) and Zn(II) with N, N-di (o-hydroxybenzenoylmethylene) Ethylenediamine

The Schiff’s base ligands and their complexes with Ni(II), Cu(II) and Zn(II) were synthesized and characterized by elemental analysis molar conductivity, infrared and ultraviolet-visible spectroscopy and magnetic susceptibility measurements. The ligands, ethylenedianil of o-hydroxyphenylglyoxal, C18H16N2O4, have been synthesized by condensation of ethylenediamine and orthohydroxyphenylglyoxal. The metal complexes were prepared by mixing of saturated solutions of ligands and metal salts in appropriate molar ratio in acetone and methanol solvents. The study also confirmed the formation of mono-, di- and trinuclear isopolystructures of the complexes in square planar geometry except for Zn(II), which has tetrahedral stereochemistry. The synthesized ligands and their metal complexes were screened for their antimicrobial activities against two bacterial strains (Staphylococcus aureous and Xanthomonas holcicola), and two fungal strains (Aspergillus niger and Fusarium oxysporum) using a disc diffusion method. The tests showed that the complexes have higher antimicrobial activity than the free Schiff’s base.

Evaluation of industrial dairy waste (milk dust powder) for acetone-butanol-ethanol production by solventogenic Clostridium species.

Readily available inexpensive substrate with high product yield is the key to restoring acetone-butanol-ethanol (ABE) fermentation to economic competitiveness. Lactose-replete cheese whey tends to favor the production of butanol over acetone. In the current study, we investigated the fermentability of milk dust powder with high lactose content, for ABE production by Clostridium acetobutylicum and Clostridium beijerinckii. Both microorganisms produced 7.3 and 5.8 g/L of butanol respectively, with total ABE concentrations of 10.3 and 8.2 g/L, respectively. Compared to fermentation with glucose, fermentation of milk dust powder increased butanol to acetone ratio by 16% and 36% for C. acetobutylicum and C. beijerinckii, respectively. While these results demonstrate the fermentability of milk dust powder, the physico-chemical properties of milk dust powder appeared to limit sugar utilization, growth and ABE production. Further work aimed at improving the texture of milk dust powder-based medium would likely improve lactose utilization and ABE production.

Rheological characteristics of nitrate glycerol ether cellulose gel based on phase separation in ternary system

By non-solvent-induced phase separation, nitrate glycerol ether cellulose (NGEC) gels were formed in ternary NGEC/acetone/ethanol system. The rheological behaviors of NGEC gels were investigated using dynamic rheological measurements. The final compositions and morphologies of NGEC gels were influenced by the initial solvent/non-solvent (acetone/ethanol) ratios and NGEC concentrations. In addition, the effect of initial acetone/ethanol ratios on the characteristics of NGEC gels is different from the effect of NGEC concentrations. The critical strain of NGEC gels decreased almost with increasing NGEC concentration of gels by increasing initial acetone ratio, but it increased with increasing NGEC concentration of gels by increasing NGEC concentration beyond a certain concentration in 2/3 (w/w) acetone/ethanol solution. For all gels, the storage modulus (G′) and loss modulus (G′′) of NGEC gels rapidly increased with increasing NGEC concentration of gels. In addition, the curves for G′ and G′′ were temperature sensitive throughout the entire temperature sweep, which implied that the interactions between NGEC/solvent could be disrupted upon heating to higher temperatures.

Engineering Clostridium acetobutylicum for production of kerosene and diesel blendstock precursors

Processes for the biotechnological production of kerosene and diesel blendstocks are often economically unattractive due to low yields and product titers. Recently, Clostridium acetobutylicum fermentation products acetone, butanol, and ethanol (ABE) were shown to serve as precursors for catalytic upgrading to higher chain-length molecules that can be used as fuel substitutes. To produce suitable kerosene and diesel blendstocks, the butanol:acetone ratio of fermentation products needs to be increased to 2–2.5:1, while ethanol production is minimized. Here we show that the overexpression of selected proteins changes the ratio of ABE products relative to the wild type ATCC 824 strain. Overexpression of the native alcohol/aldehyde dehydrogenase (AAD) has been reported to primarily increase ethanol formation in C. acetobutylicum. We found that overexpression of the AADD485G variant increased ethanol titers by 294%. Catalytic upgrading of the 824(aadD485G) ABE products resulted in a blend with nearly 50wt%≤C9 products, which are unsuitable for diesel. To selectively increase butanol production, C. beijerinckii aldehyde dehydrogenase and C. ljungdhalii butanol dehydrogenase were co-expressed (strain designate 824(Cb ald-Cl bdh)), which increased butanol titers by 27% to 16.9gL−1 while acetone and ethanol titers remained essentially unaffected. The solvent ratio from 824(Cb ald-Cl bdh) resulted in more than 80wt% of catalysis products having a carbon chain length≥C11 which amounts to 9.8gL−1 of products suitable as kerosene or diesel blendstock based on fermentation volume. To further increase solvent production, we investigated expression of both native and heterologous chaperones in C. acetobutylicum. Expression of a heat shock protein (HSP33) from Bacillus psychrosaccharolyticus increased the total solvent titer by 22%. Co-expression of HSP33 and aldehyde/butanol dehydrogenases further increased ABE formation as well as acetone and butanol yields. HSP33 was identified as the first heterologous chaperone that significantly increases solvent titers above wild type C. acetobutylicum levels, which can be combined with metabolic engineering to further increase solvent production.

Retracted: Acid‐Catalyzed Aquation of Ni(II)‐Hydrazone Complexes: Kinetics and Solvent Effect

ABSTRACTComplexes of the type [Ni(L)(H2O)]Cl2·nH2O, where L = 2‐pyridyl‐3‐isatinbishydrazone ligands, have been synthesized and characterized on the bases of elemental analysis, molar conductance, IR, electronic spectra, and thermal analysis (TGA and DTA). Acid‐catalyzed aquation of the Ni(II) isatin‐bishydrazone complexes was followed spectrophotometrically in various water–methanol and water–acetone mixtures at temperature 298 K. Kinetic behavior of the acid aquation is a linear rate law, indicating that the acid‐catalyzed aquation of these complexes in water–methanol and water–acetone mixtures follows a rate law with kobs = k2[H+]. The effect of the mole fraction of the ganic solvent, i.e., methanol and acetone, on the acid aquation has been analyzed; the decrease in the rate constant values with increasing of the methanol or acetone ratios is attributable to the effect of the co‐organic solvent on the initial states of the acid aquation by the destabilization of the H+ ion.

Detection of relative [Na+] and [K+] levels in sweat with optical measurements

We describe the use of 2-hydroxy-1,4-naphthoquinone (HNQ, Lawsone) as a potential sweat electrolyte measurement marker. We use ultraviolet-visible absorbance measurements to determine the absorbance energy in a particular wavelength range (400 nm–500 nm). This novel approach allows us to eliminate the importance of the exact wavelength of the absorbance peak but find the integral of the range of interest. Although we numerically calculate the absorbance energy, it is imperative to use photodiodes to measure the intensity of the transmitted light that is fabricated particularly for the range of interest for future device implementations. We explored various mixing ratios of water and acetone to find the optimum solvent that would give the most sensitive and accurate relative electrolyte sensing. The pH value was also modified to see the effect on the absorbance energy and intensity. A representative group of subjects were used to collect sweat from the dehydration and hyperhydration cases. The results are convincing that HNQ solutions can be used as a wearable, continuous sweat sensor.

Model Construction for Butanol Fermentations with Acetate/Butyrate Added by Graph Theory

Acetate /butyrate metabolic pathways play an important role in ABE fermentation and their changes will influence entire carbon fluxes distribution. Several fermentations with intermittent feeding of acetate / butyrate were conducted in a 7 L fermentor and the results indicated that exogenous acetate / butyrate enhanced solvents productivities by 47. 1% and 39. 2% respectively,and butanol / acetone ratios were improved by 21. 7% for butyrate added batch and decreased by 16. 2% for acetate added batch. A nonlinear constraint was utilized for acids rates calculation and the results revealed that acetate / butyrate formation pathways were almost blocked by corresponding acids feeding. Then a metabolic model constructed by graph theory was utilized to dispose those cases with acetate / butyrate added and to predict solvents production,in which some improvements were adopted based on the calculation results and related references. The model predicted solvents production, butanol / acetone ratios accurately and constructed the directed signal flow diagrams of ABE network under different conditions correctly.

Photochemical Production of Atmospheric Carbonyls in a Rural Area in Southern China

For the first time, ambient carbonyls were measured in a rural area in southern China from August 2012 to February 2013 to investigate their distribution characteristics and sources. Formaldehyde, acetaldehyde, and acetone were the three most abundant carbonyls, which accounted for 83-95 % of total seven carbonyls identified. The O3 formation potential of carbonyls in summer (59.55 μg/m(3)) was approximately ten times greater than that (6.37 μg/m(3)) in winter, and calculated photolysis rates were significantly faster in summer than those in winter, suggesting intensive photochemical activities in summer. Seasonal and diurnal variations of carbonyls showed that (1) the concentration of total carbonyls in summer (12.62 ± 10.83 μg/m(3)) was approximately five times greater than that in winter (2.33 ± 0.90 μg/m(3)), and a similar trend applied to the three abundant carbonyls; (2) the average summer to winter (S/W) ratio of formaldehyde and acetaldehyde was 10-13, and the S/W ratio of acetone was ~2.59; and (3) the highest concentrations of the three carbonyls and total carbonyls occurred at 14:00-16:00 with high temperature and intensive sunlight, especially in summer. These variations provided direct evidence for significant photochemical production of ambient carbonyls. Average C1/C2 ratios (3.07 ± 1.62) in summer were much greater than those (1.28 ± 0.25) in winter, and average C2/C3 ratios (35.09 ± 58.67) in summer were significantly greater than those (4.75 ± 2.12) in winter, both cases indirectly implying positive photochemical productions in summer. Especially, strong correlations (R(2) = 0.63-0.98) of temperature and sunlight intensity with the three abundant carbonyls and total carbonyls were observed, indicating a similar causal source such as significant photochemical production.

Magnetic Field Assisted Electrospinning of Nanofibers Using Solutions with PVDF and Fe3O4Nanoparticles

ABSTRACTThis study aims at investigating the formation of nanofibers containing poly (vinylidene fluoride) (PVDF) and Fe3O4 nanoparticles using magnetic field assisted electrospinning. For this purpose, two Helmholtz coils were mounted on the electrospinning apparatus in order to create a uniform magnetic field. Different separations, angles and magnetic fields are being analyzed. Polymeric solutions containing PVDF, DMF and acetone with a concentration of 18 wt% were adopted (DMF to Acetone ratio of 3 to 1). Iron Oxide Nanopowder (Fe3O4, particle diameter of 20 nm to 30 nm) to PVDF ratios are 1:5, 1:10 and 1:15. The application of the electromagnetic field during fiber deposition results in better orientation of the polymer flow towards the grounded electrode and leads to smoother fibers with diameters in the range of hundreds of nanometers. Blisters, probably related to Fe3O4 agglomerates, were distributed on the surface of all samples of this study. A magnetic field response of the nanofibers with higher magnetic fields was clear observed. By adding more Fe3O4 to the polymeric solution the ferromagnetic response on thin films and nanofibers was improved. The analysis of circular capacitors revealed a full dielectric response.

염산과 아세톤의 혼합용매를 이용한 Dowex21K XLT 수지에 흡착된 금과 구리-시안 착화합물의 탈착 특성

Abstract : To efficiently desorb gold and copper-cyanide complexes adsorbed onto Dowex21K XLT resin, the mixed solvent with HCl and acetone which is a kind of dipolar aprotic solvent was used as a desorbing agent. The desorption efficiency for gold-cyanide complex was the highest as about 94% when the mixing ratio of HCl and acetone based on volume was the 7:3, however, the value decreased as the ratio of acetone increased. In the case of copper-cyanide complex, most of them was desorbe d when the amount of HCl was relatively higher than that of acetone, however, desorption efficiency decreased as the ratio of acetone increased. The desorption efficiency for gold and copper-cyanide complexes was the 94 and 100%, respectively at the 0.6 M of HCl with the 7 (HCl) : 3 (Acetone) of mixing ratio and desorption efficiency for gold-cyanide complex not increased any more even though higher HCl concentration was used. And the desorption efficiency for gold and copper-cyanide complexes was about 100% at the S/L raio ≦ 1.0 whereas desorption efficiency for gold-cyanide complex was very low as about 20-29% at the S/L ratio > 1.0. Also, most of desorption process for gold and copper-cyanide complexes was completed within 120 min.

Characterisation of cellulose films regenerated from acetone/water coagulants

A precooled aqueous solution of 7wt% NaOH/12wt% urea was used to dissolve cellulose up to a concentration of 2wt%, which was then coagulated in an acetone/water mixture to regenerate cellulose film. The volume ratio of acetone to water (φ) had a dominant influence on film dimensional stability, film-forming ability, micromorphology, and mechanical strength. The film regenerated at φ=2.0 showed excellent performance in both dimensional stability and film-forming ability. Compared to that from pure acetone, the cellulose film from the acetone/water mixture with φ=2.0 was more densely interwoven, since the cellulosic fibrils formed during regeneration had pores with smaller average diameter. The alkali capsulated in the film during film formation could be released at quite a slow rate into the surrounding aqueous solution. The regenerated cellulose film with adjustable structure and properties may have potential applications in drug release and ultra filtration.

The Preparation Of PLGA-PLL-Peg Nanoparticles Simultaneously Loaded With Daunorubicin and Tetrandrine By Modified Double-Emulsion Method

A functional polymer composed of PLGA, PLL and PEG was synthesized, which was used as carrier material for fabricating drug delivery system of nanoparticles. PLGA-PLL-PEG nanoparticles simultaneously loaded with daunorubicin (DNR) and tetrandrine (Tet) were prepared in order to inhibit MDR activity and enhance the antitumor activity of DNR. A modified double-emulsion solvent evaporation/diffusion method was used to increase the incorporation of DNR (hydrophilic) and Tet (hydrophobic) into PLGA-PLL-PEG nanoparticles (NPs). The influence of various processing parameters on particle size and drug loadings were investigated systematically, such as the molecular weight, such as the molecular weight and concentration of PLGA-PLL-PEG, volume ratio of acetone to dichloromethane, PVA concentration in the external aqueous phase, the volume ratio of internal aqueous phase to external aqueous phase and the surfactants of internal aqueous phase. The particle size of the nanoparticles produced by optimized formulation and preparation was 213.0±12 nm (n = 3) with low polydispersity index (0.075 ± 0.023, n = 3). Transmission electron microscopy (TEM) examination showed that the morphology of the prepared nanoparticles was spherical in shape with a smooth surface. The drug loadings were 3.63±0.15% for DNR and 4.27±0.13% for Tet (n = 3). The entrapment efficiencies were 70.23±1.91% for DNR and 86.5±0.7% for Tet (n = 3). The release of DNR and Tet were sustained over one week. The PLGA-PLL-PEG-NPs formulation was potentially useful for hydrophilic and hydrophobic drugs that require efficient delivery to cancer cells. Disclosures:No relevant conflicts of interest to declare.

Preliminary Researches on Conditions to Extract Chlorophyll from Leaves of Wedelia Trilobata (L.) Hitchc

Among the extractants used, the extraction effect by acetone was the best, and the one by mixed extractant B was the second. The extraction effect declined gradually according to the order below: acetone &gt;mixed extractant B &gt;alcohol &gt;95% alcohol &gt;ethyl acetate &gt;80% acetone &gt;90% acetone &gt;mixed extractant A &gt;aether. Otherwise, when extraction time was 10 min, the extraction effect by acetone was the best. When dosage was 5 mL, the extraction effect by acetone was the best. With 95% alcohol being used to prepare extractants with acetone, the extraction effect was the best when the volume ratio of acetone and 95% alcohol was 2:1. With alcohol solution of different concentration being used to prepare extractants with acetone, where acetone/alcohol solution volume ratio was 2:1, the extraction effect was the best when the concentration of alcohol solution was 75% (v/v).

Three-Step Chemo Enzymatic Continuous-Flow Cascade Synthesis of 1-Monoacylglycerol

Abstract In this work, a three-step chemo enzymatic cascade reaction is reported for 1-monoacylglycerols from glycerol derived from biodiesel industry under continuous-flow conditions. Glycerol protection was performed using H2SO4/SiO2 (2.5% w/v) solid catalyst and acetone, generating 87% of solketal under 55 °C at 0.1 mL/min with glycerol–acetone ratio of 1.5:1. Coupled esterification between the formed solketal and stearic acid catalyzed by Rhizomucor miehei enzyme (RM IM) was able to maintain 90% of conversion until 1.5 M of substrate concentration at 0.1 mL/min flow rate and could be recycled up to 18 times. Final ketal cleavage was performed with the same H2SO4/SiO2 solid catalyst and the amount of water generated in the esterification reaction, whereas a flow rate of 0.2 mL/min was the best condition where the formation of 1-monoacylglycerol was maximized and byproducts were not detected.

Design and evaluation of mucoadhesive beads of glipizide as a controlled release drug delivery system

The present work aims at the development of a low-cost controlled release system of glipizide beads embedded in pectin to overcome the problem of frequent dosing of drug. The method of preparation has been optimised by experimental design to achieve satisfactory responses with respect to controlling variables. The controlling variables are X1, drug–polymer ratio; X2, surfactant concentration and X3, isooctane–acetone ratio. The most effective combination is X1(1:6), X2(1%), X3(50:50). Various parameters such as mucoadhesivity and swellability of beads, characterisation, dissolution, stability, ex vivo absorption and in vivo (Oral glucose tolerance test in rat) studies were performed with the optimised product. The optimised product was found quiet satisfactory that showed yield of 86.78%, drug entrapment efficiency (DEE) of 87.38% and drug release was extended up to 18 h. The present formulation of glipizide is a promising multiparticulate system of glipizide with significant hypoglycemic effect, and moreover it was prepared rapidly with ease.