Abstract  In this Technical Note, the use of a liquid metal, i.e., a low melting point Pb-Sn-In-Bi alloy, as the phase change material (PCM) in thermal energy storage-based heat sinks is tested in comparison to an organic PCM (1-octadecanol) having a similar melting point of similar to 60 degrees C. The thermophysical properties of the two types of PCM are characterized, revealing that the liquid metal is much more conductive while both have nearly identical volumetric latent heat of fusion (similar to 215 MJ/m(3)). By using at the same volume of 80 mL, i.e., the same energy storage capacity, the liquid metal is shown to outperform significantly over the organic PCM under the various heating powers up to 105.3 W/cm(2). During the heating period, the use of the liquid metal leads to a remarkable extension of the effective protection time to nearly twice longer as well as a reduction of the highest overheating temperature by up to 50 degrees C. The cool-down period can also be shortened significantly by taking advantage of the much higher thermal conductivity of the liquid metal. These findings suggest that liquid metals could serve as a promising PCM candidate for particular applications where the volume limit is very rigorous and the penalty in weight increment is acceptable. (C) 2016 Elsevier Ltd. All rights reserved.

Abstract  In this work, a new thermodynamic method, based on the McMillan-Mayer solution theory, is proposed to interpret and predict the solubility of low- and high-molecular-weight compounds in compressed CO2. In the thermodynamic approach presented here, the solute is referred to as a pseudo pure component while the compressed CO2 is represented as a continuous medium that affects the interactions among solute molecules. The perturbed-hard-sphere-chain (PHSC) theory is used within the McMillan-Mayer framework to derive an expression for the repulsive and attractive contributions to the Helmholtz free energy of the solute.

While easy to handle, the model enlightens the effects of molecular weight and other physical-chemical characteristics on compounds solubility in compressed media. The thermodynamic approach fairly describes the experimental data concerning the solubility of several substances in compressed CO2 at different temperatures. The model also predicts CO2 solubility in PEG polymer and semi-quantitatively reproduces high-molecular-weight component solubility in compressed CO2 containing low amount of ethanol as co-solvent. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract  The localized surface plasmon resonance (LSPR) behavior of indium-doped ZnO (IZO) nanocrystals synthesized in different solvents was studied. 1-octadecanol, oleic acid, oleyl alcohol, oleyl amine and 1-octadecene were used as solvent(s) and co-solvent(s) in the pyrolysis synthesis of indium-doped ZnO (IZO) nanoparticles. The results showed that the nanocrystals from a solvent system consisting of 1-octadecene, 1-octadecanol, and oleic acid exhibited enhanced LSPR near-infrared radiation absorption without sacrificing transparency in the visible region. The indium-rich core verified using ICP and XPS analysis was shown to be critical for the enhancement. The reaction mechanism of solvents on the generation of indium-rich core was elucidated through a systematic study of the reaction parameters. The interaction between the activating agent, inhibiting agent and solvent, and their effect on tuning the reactivity of dopant and host precursors were important for the formation of a nanostructure with a dopant-rich core. The solvent effect was also found in the synthesis of gallium-doped ZnO and confirmed to be a general phenomenon in the preparation of doped ZnO nanoparticles.

Abstract  ES-285(.)HCl [(2S,3R)-2-amino-3-octadecanol hydrochloride] is a novel investigational anticancer agent, which has shown in vitro and in vivo cytotoxic activity against various tumor cell lines with selectivity for certain solid tumors. The pharmaceutical development of ES-285(.)HCl warranted the availability of an assay for the quantification and purity determination of ES-285(.)HCl active pharmaceutical ingredient (API) and its pharmaceutical dosage form. A liquid chromatographic method (LC) comprising of derivatisation of ES-285(.)HCl with phenylisothiocyanate and UV-detection was developed. The method was found to be linear, precise and accurate. The assay also proved selectivity as determined by analysing ES-285(.)HCl in combination with 15 analogues and in combination with hydroxypropyl-beta-cyclodextrin, the excipient used in the lyophilised pharmaceutical dosage form. Stress testing showed that the degradation products were separated from the parent compound, confirming its stability indicating capacity. The method was found robust as determined with design of experiments (DoE), which made it possible to predict system suitability responses in worst case experimental conditions and to define criteria for system suitability testing. (C) 2003 Elsevier B.V. All rights reserved.

Abstract  In this work, highly absorbent cross linked co-polymer gels of cis-9-octadecen-1-ol with acrylic/methacrylic acid and 1-hexene in different molar ratios were synthesized by thermal polymerization techniques and studied. The polymers were characterized by Fourier Transform-Infrared Spectroscopy, Thermogravimetric analysis and Scanning Electron Microscopy techniques. Their non-ionic nature was verified with the help of transport number measurement by Wagner polarization technique. The polymers were found to have very high swelling capacities in organic solvents like chloroform, tetrahydrofuran, ethanol, diethylether, thiophene, pyridine, and benzene. These gels show maximum swelling for chloroform which reaches up to 750%. The swelling capacities for different oils like kerosene, gasoline, engine oil, and silicon oil, are also favorable. The swelling kinetics confirmed that the swelling followed second order kinetics. The chloroform retention time was also checked which established that the gels can be recycled and reused again and again. An experiment showing removal of kerosene from kerosene/water mixture is also performed. This confirms that these gels can be used in removing organic contaminants and oil from water and can help in water purification and environmental cleanup purposes. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  The objectives of the paper are to verify the potentialities of a sequential two phase partitioning bioreactor in degrading xenobiotics and to evaluate the kinetic parameters for modelling the system. The target compound investigated was the 4-nitrophenol. Preliminary tests were carried out to define the solvent most appropriate for the compound. Among the three investigated solvents 1-undecanol, 2-undecanon and oleyl alcohol, the 2-undecanon was chosen because of the higher partition coefficient of 30 and the negligible formation of emulsions. Moreover, the tested solvent showed satisfactory "biocompatibility" characteristics for the biomass with minor effects on the intrinsic kinetics. Parallel batch kinetic tests were then performed with the conventional one phase and the two phase systems. In the two phase system the biomass is exposed for all the time to 4NP concentrations that are significantly lower if compared to the conventional system and, for the highest concentration (450 mg/l) in the two phase system a reduction of the reaction time is observed depending on the biomass concentration. Kinetic parameters were also evaluated in both cases by fitting of the experimental data with a modified form of the Haldane equation.

Abstract  A high yield synthesis of 1-triacontanol was based on the cheap and easily available starting materials 1-octadecanol and 1,12-dodecanediol. The first one was converted to octadecanal using a phase transfer system, whereas the second one after phase transfer bromination and reaction with triphenylphosphine provided 1-hydroxy-12-triphenylphosphonium bromide. Wittig reaction of these two synthons and subsequent hydrogenation furnished the desired product.

Abstract  Penetration of alkane molecules into the adsorbed film of a cationic surfactant gives rise to a surface freezing transition at the alkane-water interface upon cooling. In this paper, we show that surface freezing of hexadecyltrimethylammonium chloride (CTAC) at the tetradecane-water interface stabilizes oil-in-water (OW) emulsions. For concentrations of CTAC near the critical micelle concentration, an OW emulsion coalesced readily above the surface freezing transition whereas the OW emulsion was stable in the surface frozen state. There was a discontinuous change in the stability of the OW emulsion at a temperature very close to the surface phase transition temperature as determined by interfacial tensiometry and ellipsometry on a planar oil-water interface. The mechanical elasticity of the surface frozen layer opposes film drainage and density fluctuations that could lead to rupture and is the most likely cause of the enhanced emulsion stability.

Abstract  Evaluation of the method of preparation and the sequence of metal incorporation onto the catalyst showed that they had profound effects on the catalytic behavior of Ru Sn Al2O3 catalysts used in the selective hydrogenation of oleic acid to 9-octadecen-1-ol. When Ru was loaded first onto the support and then followed by Sn, the catalyst had lower activity but greater ability to preserve the unsaturated bond. On the other hand, when the sequence of loading was reversed, the behavior of the catalyst changed correspondingly, i.e., the catalyst showed higher activity but poorer ability to protect the unsaturated bond. The metal particles incorporated via the sol gel method were finely and evenly distributed on the support. As such, they were more readily shielded by the second metal particles that were subsequently incorporated via the impregnation process. When both metals were loaded via the sol-gel-process, the best result was obtained with superior performance in activity, as well as selectivity in the preservation of double bond.

Abstract  The interfacial tension gamma of the hexane solution of oleyl alcohol against water was measured as a function of temperature T and molality m(1) under atmospheric pressure. The entropy change associated with the adsorption triangles was dependent on both temperature and molality below about 35 mmol kg(-1) while independent of both those above about 35 mmol kg-1. The former is responsible for the contact of the double bond of oleyl alcohol with water at the hexane/water interface, but the latter is responsible for the similarity of the aggregates, which are formed by the alcohol molecules in their hexane solution, to the adsorbed films in the situation that hydrogen bonds are formed between the alcohol molecules. Considering the aggregate formation and the thermodynamic equation used, it was found that the decrease of the interfacial density Gamma(1)(H) at a high concentration region is an artifact introduced by the assumption of the ideal solution at that region. Furthermore, by drawing the interfacial pressure T versus the mean area per adsorbed molecule A curves, the onset of the phase transition comes out at high temperatures and also oleyl alcohol does not form the condensed film because of the steric hindrance of the hydrocarbon chain of the alcohol molecules. The experiments by using other oils suggested that the alkene systems obviously exhibit the phase transition. Taking notice of the affinty between water and pi-electrons and the occupied area just below and above the phase transition, it was concluded that the phase transition in this case is accompanied by the detachment of the double bond of the alcohol molecules from the interface, and therefore the driving force is the water-a-electrons interaction.

Abstract  Isotopic substitution has been used in conjunction with neutron reflection to make a selective study of the counterion layer beneath a charged insoluble monolayer spread on water. The insoluble monolayer consisted of a mixture of sodium docosyl (C-22) sulfonate and docosanol, and its charge was adjusted by varying the relative amounts of anionic and neutral species in the layer. The counterion was the tetramethylammonium ion, TMA(+). The counterion distribution was determined at three surface charge densities, corresponding to areas per negative charge of about 30, 60, and 85 Angstrom(2), and at three bulk electrolyte (TMACl) concentrations, 0.1, 0.01, and 0.001 M. There was found to be significant penetration of the counterions into the headgroup region of the amphiphile to form a well defined ''Stern'' layer, and there was also a thicker layer corresponding to part of the diffuse layer. The changes in the behavior of the counterions with changes in surface charge density and bulk electrolyte concentration were qualitatively consistent with double-layer theory. However, a complication in applying theory to the diffuse part of the double layer was that not all the counterions could be observed by the neutrons. This may have been because of preferential adsorption of Na+ present in the original spreading solution or because of roughness of the counterion distribution. The obervation by neutron reflection of penetration of the amphiphilic layer by the counterions was consistent with the unusual behavior of the pi-A isotherms on addition of TMACl.

Abstract  Vegetable oil-based oils usually fail to meet the rigorous demands of industrial lubricants by not having acceptable low temperature properties, pour point (PP) and/or cloud point (CP). Oleic estolide was produced from oleic fatty acid and a catalytic amount of perchloric acid. The oleic estolide was then esterifled with a series of 16 different alcohols that were either branched or linear-chained. The new estolide esters physical properties were recorded and evaluated as a potential industrial lubricant. The linear-chain esters had higher low temperature properties (PP = -9 to 33 degrees C) but still compete well with other commercial bio-based materials. The oleic estolide ethyl ester yielded the best PP at -33 degrees C for the linear-chain series. The branched alcohol produced the best PP (-24 to - 39 degrees C) and CP (-30 to <-50 degrees C) with the best PP performers being a 2-hexyldecanol (Jarcol 1-16) sample, a 16 carbon-chained branched material, and 2-octyldodecanol (Jarcol 1-20), a 20 carbon branched material, with a PP at -39 degrees C. The best CP performers from the same series were the 2-octyldodecanol, with a CP lower than -50 degrees C followed by the 2-hexyldecanol at -42 degrees C. The viscosities (55-209 cSt @40 degrees C) and viscosity indexes (VIs) (169-192) performed well. The iso-stearyl alcohol (Oxocol 180) sample had the highest viscosity at 40 degrees C of 209.3 cSt which was higher than all other materials tested. Finally, these new estolide esters required no additives in order to obtain the improved performance in low temperature physical properties, thus limiting our impact on the environment and replacing fluids that are based on non renewable resources. Published by Elsevier B.V.

Abstract  A mixed oxide catalyst was prepared from a binary hyrdrogen storage alloy, Mg2Cu, and its activity and selectivity were compared with those of conventional CuCrO catalyst. The catalyst's activity was stable for the synthesis of C18 alcohol by gas-phase hydrogenolysis of methyl oleate in a continuous-flow reactor at 553 K under atmospheric pressure. Considerable amounts of unsaturated alcohol were produced together with saturated alcohol. From a kinetic study the rate equation was formulated for each alcohol. From XRD analysis, active sites are thought to be copper species on MgO support.

Abstract  The initially hydrophobic surface of as-prepared luminescent stain-etched porous Si powder is made hydrophilic by means of the physical adsorption of different nonionic surfactants. Unsaturated linear hydrocarbons (undecylenic acid and oleyl alcohol) are found to provide the best durability of aqueous suspensions of porous Si powder, maintaining the ability of excited Si nanocrystals to interact with molecular oxygen by means of electronic energy transfer.

Abstract  Esterification of adipic acid and oleyl alcohol in a solvent-free system featuring a stirred tank reactor containing commercially immobilized Candida antarctica lipase B was performed. The process was carried out using an artificial neural network (ANN) trained by the Levenberg-Marquardt (LM) algorithm. The effects of four operative variables, temperature, time, amount of enzyme, and impeller speed, on the reaction yield were studied. By examining different ANN configurations, the best network was found to consist of seven hidden nodes using a hyperbolic tangent sigmoid transfer function. The values of the coefficient of determination (R-2) and root mean squared error (RMSE) between the actual and predicted responses were determined to be 1 and 0.0058178 for training and 0.99467 and 0.622540 for the testing datasets, respectively. These results imply that the developed model was capable of predicting the esterification yield. The operative variables affected the yield, and their order of contribution was as follows: time > amount of enzyme > temperature > impeller speed. A high percentage of yield (95.7%) was obtained using a low level of enzyme (2.5% w/w), and the temperature, time, and impeller speed were 66.5 degrees C, 354 min (about 6 h), and 500 rpm, respectively. A simple protocol for efficient substrate conversion in a solvent-free system evidenced by high enzyme stability is indicative of successful ester synthesis.

Abstract  The impact of the metal nature and framework type on the textural, acidic, and catalytic properties of M-MOF-74 (M=Co, Cu, Mg, Ni) and M-MIL-100 (M=Al, Cr, Sc, V) materials was evaluated. Both metal-organic framework (MOF) families showed 100% selectivity to the tetrahydropyranyl ether for all alcohols (methanol, 1-propanol, 1-octanol, 2-adamantanol, 1-octadecanol) applied. Independently of the metal employed in the synthesis of M-MOF-74, the conversions were lower than those obtained with M-MIL-100. This result can be attributed to the combination of superior textural properties, accessibility, and strength of open metal sites in M-MIL-100 that improve the ac-cessibility/diffusion of reactant and products. The variation of the size and shape of the alcohols on the activity and selectivity showed that the yield of tetrahydropyranyl ether decreased with increase of the alcohol size (methanol<1-propanol<1octanol<2-adamantanol<1-octadecanol). The best catalytic results were achieved with V-MIL-100, and were even maintained after several cycles; this could be related to the superior polarizing power of V-containing units, which enhanced the activation of 3,4-dihydro-2H-pyran and, consequently, the yield of the target ether.

Abstract  Heterogeneous nucleation and condensation of dibutylphthalate, octadecane, octadecanol, and octadecanoic acid vapors at various pressures on insoluble AgCl and Ag nanoparticles in a turbulent mixing condensation nuclei counter (TMCNC) have been studied theoretically. A method to interpret the particle size distributions measured with a DMA and estimate the parameters for nucleation on single particles is proposed. Based on this semi-empirical method, the Gibbs free energy is calculated and a rate of heterogeneous nucleation on single particles is estimated directly from the experimental "condensation spectra" of inactive and active CN using the DMA data. In some cases, the dependence of the Gibbs nucleation energy on the vapor supersaturation had two maximums and one minimum, instead of one maximum as described by Gibbs' classical thermodynamics of phase transitions. This phenomenon, called "double barrier nucleation" (DBN) is caused by the surface heterogeneity of nano-CN; this is first experimental verification of DBN that had been previously predicted theoretically. Two types of heterogeneity may be present: topographic or energetic. Focusing on energetic heterogeneity, a theoretical model of DBN for spherical geometry is developed. The surface heterogeneity for insoluble nano-sized CN is shown to be critical to explaining the unusual transformation of a monomodal size distribution of inactive CN into a bimodal distribution of activated CN when coagulation is excluded. Future studies will be directed toward more data for further refining the theory and developing a model that simultaneously accounts for both types of surface heterogeneity of nano-CN. (c) 2006 Elsevier B.V. All rights reserved.

Abstract  In this paper, the MCM-48 framework containing Ti, Co, Zr, Crt Mn, Cu and Mo was synthesized and characterized by means of HRTEM, pore diameter distribution, XRD, XPS and IR absorption spectra, In addition, we also studied their catalysis behavior for the conversion from eicosanol to eicosanic acid. The experimental results show that the Ti, Cr, Zr doped MCM-48 pocesses excellent catalysis properties.

Abstract  Phenylisocyanate (PhNCO) reaction with ethanol (EtOH) at high alcohol self-association degree was studied. By using High Performance Liquid Chromatography method (HPLC), differential kinetic behavior of 1,4-butane-diol (BD) and EtOH in some of their mixture during reaction with PhNCO was searched. Synergetic influence between the reaction reactive species was evidenced. The most reactive hydroxilic compound in the studied mixtures are ED. This evidence, beside the kinetical behavior of EtOH in a large scale of self-association, suggested that alcohol linear dimeric forms, as well as the ends of linear associate play a decisive role in urethane reaction. Within urethanes formation reaction, both alcohol and isocyanate molecules participate in activated forms. The activation is realized in both cases by assistance of other alcohol or urethane molecule. The similitude between alcohol and urethane activation effect allows the use of kinetical equations of second order to describe with a good precision the evolution of reaction in all the studied cases. Good concordance between different urethane reaction rate constants and the hydrogen bond life time of the corresponding hydroxylic compound determined by ultrafast pulsed spectroscopy was found.

Abstract  The effect of feed pH and temperature were examined for the extraction of penicillin G from aqueous solutions. Equilibrium experiments were first carried out to establish the carrier and the solvent for better extraction in the organic phase. The feed pH was varied in the range 4.5-7 to determine the extractability of the carrier-solvent system. Organic phases consisting of the carriers Aliquat 336 and Amberlite LA-2 in the solvents Shellsol TK and oleyl alcohol gave good values of the distribution coefficient at room temperature. The distribution coefficients were greater at temperatures higher than the room temperature. Re-extraction (recovery) experiments were carried out by using an aqueous solution of salts; sodium carbonate performed better than sodium chloride. These processes were scaled up using a pilot-scale hollow-fiber membrane module (HFMM). The module (6 cm x 20 cm) had a total of 10000 microporous polypropylene hollow fibers with an effective mass transfer area of 1.4 m(2). The extraction was performed by contacting a 'feed' solution containing penicillin G (flowing in the fiber side) with an 'organic phase' of Aliquat 336 in Shellsol TK or oleyl alcohol (flowing on the shell side) of the membrane contactor. An organic phase of 5% Aliquat 336 in both the solvents Shellsol TK and oleyl alcohol achieved extraction at pH 7 in the range 40-45% within 1 h at a recirculating feed flow rate of 14.4 l/h. The operating temperature affected the percentage extraction slightly and it increased with temperature before reaching a plateau at 25-30 degrees C. For recovery of penicillin G from the organic phase, experiments were carried out using aqueous solutions of sodium carbonate and sodium chloride. Sodium carbonate at pH 11.2 gave significantly better recovery (approx. 98%) compared to sodium chloride at pH 6.7 (approx. 38%) within 1.5 h. (c) 2007 Curtin University of Technology and John Wiley & Sons, Ltd.

Abstract  Poly(vinyl alcohol) (PVA)-In2O3 (with 1 and 5 wt% In2O3 loading) nanocomposite films have been prepared by a solvent-casting technique. The In2O3 nanoparticles used in this work were prepared by nonhydrolytic alcoholysis ester elimination reaction of indium acetate in the presence of oleic acid and oleyl alcohol at 220 degrees C. X-Ray diffraction (XRD) patterns and transmission electron microscopy (TEM) studies indicate that the In2O3 nanocrystals obtained in this work are nearly monodisperse, highly crystalline with cubic bixbyite structure without the presence of any other impurity phase. The PVA-In2O3 nanocomposite films have been structurally characterized by XRD, Fourier transform infrared (FTIR) and Raman spectroscopy. The results confirm the incorporation of In2O3 nanocrystals in the PVA matrix and interactions between In2O3 nanocrystals and PVA molecules. The thermal properties of nanocomposite films have been investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermo-oxidative degradation temperature of PVA increases with the addition of In2O3 nanocrystals and the degree of crystallinity of the PVA matrix decreases in the presence of In2O3 nanocrystals in the nanocomposite films. The room temperature sensing characteristics of the naocomposite films have been studied for various gases, namely, H2S, NH3, CH3, CO, and NO. The PVA-In2O3 nanocomposite films show maximum sensitivity for H2S gas with fast response and reversibility. The response mechanism of the nanocomposite films to various gases is also proposed.

Abstract  Selected fluorinated and hydrogenated surfactants, namely a semifluorinated alkane (SFA): 1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-henicosafluorononacosane (F10H19), two long chain alcohols: 18,18,18,17,17,16,16,15,15,14,14,13,13,12,12,11,11-heptadecafluorooctadecane-1-ol (F8H10OH) and octadecane-1-ol (C18OH) and with two long chain thiols of the analogous apolar part structure to the above-mentioned alcohols, i.e.: 18,18,18,17,17,16,16,15,15,14,14,13,13,12,12,11,11-heptadecafluorooctadecane-1-thiol (F8H10SH) and octadecane-1-thiol (C18SH) have been tested in mixtures with valinomycin as potential artificial matrixes for its immobilization. The thermodynamic analysis (DeltaG(exc)vsX(val) plots) based on surface pressure-area isotherm registration for particular valinomycin/surfactant mixtures, complemented with BAM images of the films structure indicate that only fluorinated surfactants are suitable materials for valinomycin incorporation as they form homogeneous miscible monolayers at X(val) below 0.5.

Abstract  In order to extract or remove organic acids from kiwifruit juice, we evaluated their separation and transport rates through supported liquid membranes (SLMs). The liquid membrane consisted of an organic solution composed of a carrier (Aliquat 336/Alamine 336) and a linear alcohol (oleyl alcohol) and was loaded on a microporous polypropylene support (commercial grade Celgard 2500/2400). These SLMs were evaluated (i) in a batch cell to determine the permeability and (ii) in a continuous spiral membrane module to study the effects of various process parameters - flow of feed and strip solutions, membrane composition, recycling mode of operation and kiwifruit juice at natural pH. It was observed that there exists an optimum for each system: pH 2.5- 3.0 for Alamine 336/oleyl alcohol and pH 4.5 for Aliquat 336/oleyl alcohol. At this pH the flux rates of citric acid and malic acid was greater (6-8 times) than that of quinic acid. The flux rates decreased (greatly for citric acid) with the flow rate of feed and strip solutions and increased (considerably for citric acid) with the SLM composition. The recycling of feed and strip solutions significantly improved the removal efficiency. The SLM system retained its performance over a period of a few days. The SLM process allowed extraction of the above three organic acids (ascorbic acid was removed in trace amounts) from kiwifruit juice at a rate of a few percent (5%) in a single-pass processing.

Abstract  The chemical composition of the volatile fractions obtained by steam distillation from the capitula (C) and the aerial parts of Rhaponticum acaule DC were analysed by GC-MS. From the 57 identified constituents, representing 95.5% and 96.3% of the two oils, respectively, methyl eugenol, epi-13 manool, beta-ionone, beta-bisabolol, 1-octadecanol, phytol and farnesyl acetate were found to be the main components. Furthermore, the oils were tested against six Gram-positive and Gram-negative bacteria and four phytopathogenic fungi. It was found that oils from both parts of R. acaule, and especially that of C, exhibited interesting antibacterial activity, but no antifungal activity was observed.