Addition Of 1-propanol Research Articles

Fatty acids propyl esters: Synthesis optimization and application properties of their blends with diesel and 1-propanol

This paper studied the influence of four reaction parameters–temperature (40–80 °C), time (1–3 h), mass % of catalyst (1–3 wt%) and molar ratio of 1-propanol to sunflower oil (6:1–10:1)–on the conversion of biodiesel. To achieve a conversion of 95% or above, the transesterification was optimized to reduce the time, temperature, molar ratio of 1-propanol to sunflower oil and mass % of catalyst. The optimal conditions were a temperature of 40 °C, time of 1 h, 1-propanol to oil molar ratio at 8.71:1 and mass % of catalyst of 1.96%. The fatty acid propyl esters (FAPRE) were purified and blended with 1-propanol and mineral diesel to determine the application properties as transportation fuels. The addition of FAPRE to diesel increases the density and viscosity and improves the lubricity with no effect on CFPP even with 10 vol% of FAPRE. On the contrary, the addition of 1-propanol in the FAPRE-diesel blends had an opposite effect (decrease in density, viscosity and lubricity). Nevertheless, all the blends satisfied the requirements according to EN 590 for the tested properties.

A comprehensive kinetic study on the electrocatalytic oxidation of propanols in aqueous solution

The anodic peak current of a modified carbon paste electrode (CPE) with AgBr nanoparticles was increased in cyclic voltammetry (CV) by addition of 1-propanol or 2- propanol to supporting HCl electrolyte at pH 2.5. The kinetic aspects of the modified AgBr-CPE electrode response were studied in the absence and presence of the alcohols. The electrode response was irreversible based on a 135 mV difference for Epa-Epc and Ipa/Ipc = 0.88 for the AgIBr/AgIIBr redox process. The surface coverage concentration of the electrode, Γ, was about 13.1 μmol AgBr cm−2. The charge transfer coefficient, α, was 0.72 in HCl that was changed to 0.63 and 0.68 by addition of 1-propanol and 2-propanol in CV experiments, respectively, while its value was respectively changed from 0.72 to 0.61 and 0.51 in Tafel plots in LSV (linear sweep voltammetry). The rate constant value (k) was changed from 0.34 s−1 to 0.66 and 0.58 s−1 in CV experiments and from 0.31 s−1 to 0.58 and 0.51 s−1 in LSV experiments when the mentioned alcohols were added to the solution, respectively, confirms faster reaction rate in the presence of the alcohols.

Enhanced mass transfer rate and solubility of methane via addition of alcohols for Methylosinus trichosporium OB3b fermentation

Abstract The effect of alcohol on methane–water volumetric mass transfer coefficient (kLa) and solubility of methane was investigated in this study. Various alcohols including methanol, ethanol, 1-propanol, butanol, and pentanol were added to aqueous solution and enhancement of both methane–water kLa (from 72 h−1 to 471 h−1) and solubility (from 21.72 mg/L to 30.41 mg/L) was observed, depending on alcohol type and concentration. Among all alcohols, 1-propanol exhibited largest enhancement via bubble coalescence inhibition effect. Enhanced methane–water kLa and methane solubility in aqueous solution were employed for the fermentation of Methylosinus trichosporium OB3b, and cell growth rate and maximum optical density were increased by 700% and 730%, respectively, by addition of 1-propanol.

Increased luminescence efficiency by synergistic exploitation of lipo/hydrophilic co-solvency and supramolecular design

Addition of 1-propanol in water significantly reduces interchain species in poly(diphenylenevinylene) derivatives and its cyclodextrin-threaded rotaxane.

Effect of alcohols on the heat of micellization of Pluronic F88 aqueous solutions

The effects of addition of alcohols (ethanol, 1-propanol, and 1-butanol) to Pluronic F88 aqueous solutions on heat of micellization of Pluronic F88 are carefully examined by using high sensitivity differential scanning calorimeter and dynamic light scattering. With addition of ethanol to Pluronic F88 aqueous solutions, the critical micelle temperature (CMT) increases, the heat of micellization significantly decreases, and the F88 concentration region of the unusual positive heat capacity change (attributed to impurity aggregates) occurs at higher Pluronic F88 concentrations. The addition of ethanol increases the solubility of copolymer and impurities and, hence, hinders the formation of impurity aggregates. Introduction of butanol to F88 aqueous solutions would significantly reduce the CMT but only slightly change the heat of micellization, indicating exothermic interactions of 1-butanol with poly(propylene oxide) blocks. With addition of 1-propanol, both CMT and heat of micellization decrease. With addition of 5 wt.% 1-propanol would substantially expand the F88 concentration region of the unusual positive heat capacity change, indicating a significant dissociation of impurity aggregates into micelles. In addition, the effect of alcohols on the cloud points of Pluronic F88 solutions is also carefully examined and discussed. The enthalpy-entropy compensation phenomenon for the micellization of Pluronic F88 over the concentration regions of negative/positive heat capacity changes is discussed.

Dispersion of Rod-like Particles of Nafion in Salt-Free Water/1-Propanol and Water/Ethanol Solutions.

The dispersion of perfluorinated sulfonic acid ionomers in catalyst inks is an important factor controlling the performance of catalyst layers in membrane electrode assemblies of proton exchange membrane fuel cells (PEMFCs). The effect of water/alcohol composition on the dispersion of H-Nafion in water/1-propanol and water/ethanol solutions was studied by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and (19)F nuclear magnetic resonance ((19)F NMR) spectroscopy. Hydrodynamic radii calculated from DLS decay profiles and the radii and interparticle distance of rod-like particles derived from SAXS profiles showed almost the same dependence on alcohol concentration. 1-Propanol was more effective than ethanol to induce changes in the characteristic lengths of the rod-like particles. The motional narrowing in the (19)F NMR spectra by addition of 1-propanol indicates selective solvation of the rod-like particles. We suppose this might have decreased their radii and induced their elongation, which eventually led to extension of the ordered regions as observed in the hydrodynamic radii. Our study helps to clarify the dispersion of Nafion in aqueous alcohol solutions, which has implications for the performance of PEMFCs.

Sonochemical synthesis of silver nanoparticles in Y-zeolite substrate

Silver ions can be reduced by 24 kHz ultrasonic waves in ion-exchanged Ag+–Y zeolite. In this research, silver ions were introduced into the nano-porous (1.2 nm) zeolite lattice by ion-exchange route. After the reduction process, silver nanoparticles were placed in the cavities, with a size of about 1 nm and also on the external surfaces of the zeolite, with sizes about less than 10 nm. Fast and simple lab-scale reduction of silver ions in the zeolite is important for researchers who work on catalytic properties of metallic silver–zeolite. Several reduction methods have been reported but reduction by ultrasonic waves is a new, simple, and size-controllable method with a high practical value which does not need any complicated facilities. In a sonochemical process, a huge density of energy is provided by the collapse of bubbles which formed by ultrasonic waves. The released energy causes the formation of reducing radicals that consequently reduce the silver ions. It is concluded that the higher silver content may result in the formation of larger silver crystals on the external surface of zeolite crystals. Also, the addition of 1-propanol and 2-propanol to the aqueous reaction medium does not cause better reduction. In addition, increasing the irradiation time and ultrasonic power does not affect the silver crystal growth significantly but the extent of silver ion reduction increases when the power of ultrasonic waves increases. All samples were irradiated under the same ultrasonic conditions. The samples were analyzed by XRD, EDS, SEM, and TEM.

Dispersion Stability of Single-Walled Carbon Nanotubes Using Nafion in Bisolvent

We have investigated the effect of Nafion and its resulting interaction with single-walled carbon nanotubes (SWCNTs) on the solubility and dispersion properties of SWCNTs in bisolvent. Nafion was used as a polymeric dispersant, providing both electrostatic and steric stabilization in the preparation of a stable and homogeneous suspension of SWCNTs. A correlation was made between solubility and nanodispersion of SWCNTs. Optical spectroscopy showed that the solubility and nanodispersion of SWCNTs increased with the addition of 1-propanol and were greatest at a volume mixture of water/1-propanol of 80/20. We propose a mechanism of improved solubility and nanodispersion of SWCNTs, which is strongly correlated with the adsorption behavior of Nafion on SWCNTs, the surface potential of SWCNTs, and the solubility of Nafion in a liquid medium; amphiphilic Nafion enhances the dispersion of SWCNTs in the mixture of hydrophilic water and relatively hydrophobic 1-propanol.

Development of a high-performance liquid chromatography method for the determination of caspofungin with amperometric detection and its application to in vitro microdialysis experiments

Microdialysis is an increasingly employed technique for the determination of tissue pharmacokinetics. A high-performance liquid chromatography method for the quantitative determination of caspofungin in human microdialysates with amperometric detection is described. Since microdialysis of caspofungin is performed with a 100,000 molecular mass cut-off membrane, microdialysates contain protein that was precipitated at pH 4 with acetonitrile. Addition of 1-propanol (33%, v/v) to the sample extract improved the analytical recovery to 81-89%. Caspofungin and the internal standard clarithromycin were separated isocratically on a cyanopropyl silica column using acetonitrile-0.05 M citrate (33:67, v/v), adjusted to an apparent pH of 6.9, at a flow rate of 1.0 ml/min, and amperometric detection at +950 mV oxidation potential. Within-day and between-day imprecision and inaccuracy were <11%. The lower limit of quantification was 0.07 microg/ml. The method was applied to in vitro microdialysis experiments. Ringer's solution containing 1% (w/v) human albumin was used for the perfusing and surrounding medium, respectively. Albumin did not entirely prevent adsorption of caspofungin to the surface of membrane and/or tubing. When the binding-sites were saturated with albumin plus caspofungin prior to the start of sampling, the percentage of drug appearing in the microdialysate ("recovery") remained stable over the concentration range tested.

Effects of Water-Soluble Alcohols on the Surface Conductance of Lipid Monolayers: Bimodal Action

We (Yoshida et al. J. Phys. Chem. B 2000, 104, 1249) devised a submersible horizontal electrode for estimation of the conductance of surface monolayers. The effects of 1-propanol on the electrical conductance of surface monolayers of stearic, elaidic, and oleic acids were estimated. The effects depend on the structures of the hydrophobic part of the monolayers. The surface electrical conductance of a stearic acid monolayer increased 18-fold by the addition of 1-propanol. However, the response of an oleic acid monolayer was almost negligible. The result suggests that alcohol effects on the surface electrical conductance depend strongly on the packing of the monolayers, therefore it is affected by changes in the alkyl tails. Because alcohol molecules in water anchor to the monolayer surface, sandwiched water molecules between the alcohol and monolayer form two-dimensional structures. The solid condensed form of the stearic acid membrane tends to form two-dimensional structures of sandwiched water. The magnitude of their structures depends on the condensability of the monolayer. We contend that the proton flow through the hydrogen-bond network of water (electrical conductance) increases.

Demixing Pressure Measurements of Aerosol-OT in Ethane + Alcohol Solvent Mixtures

The demixing pressures (dew point pressures) for sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in supercritical ethane + alcohol cosolvent mixtures were measured in a variable-volume view cell. The alcohols studied include methanol, 1-propanol, 1-octanol, and benzyl alcohol. The temperatures studied ranged from 40 to 100 °C with overall alcohol mass fractions ranging from 0 to 0.07. The demixing pressures for AOT (1.6 mass %) in supercritical ethane with methanol, 1-propanol, and 1-octanol were found to linearly increase with temperature. The demixing pressure was found to decrease with increasing alcohol concentration at constant temperature. The differences between methanol and propanol were resolved by calculation of the demixing solvent densities. The addition of 1-octanol decreased the demixing pressure slightly less than the addition of 1-propanol (for 3 mass % cosolvent). For benzyl alcohol as the cosolvent, the demixing pressure increased with increasing cosolvent concentration and showed a very nonlinear dependence on temperature at the highest benzyl alcohol concentration studied.

Solvatochromic studies of solvation effects in reversed-phase liquid chromatography with addition of 1-propanol

The work presented here illustrates solvation effects in reversed-phase liquid chromatography in the presence of 1-propanol. A small amount of 1-propanol changes the solvatochromic parameters of the stationary phase significantly, but does not affect those of the mobile phase. Based on solvatochromic experimental results in methanol- and acetonitrile-aqueous systems, it is concluded that 1-propanol has a significant wetting effect on C 18 bonded silica stationary phases with mobile phase compositions in the medium to high water content range. Such a wetting effect is believed to affect the stationary phase composition, the organization of the C 18 chains on the surface of silica support, as well as the retention mechanism for solutes.

An Efficient Method for the Isolation and Purification of Oligoribonucleotides

Abstract Problems associated with the use of tetrabutylammonium fluoride like incomplete desilylation and removal of the tetrabutylammonium salts during large scale syntheses of oligoribonucleotides (RNA) have been eliminated by the use of triethylamine trihydrofluoride and precipitation of the RNA with 1-butanol. An efficient anion-exchange HPLC method has been developed for the purification of chemically synthesized RNA and the resulting product precipitated directly by the addition of 1-propanol. A new activator, 5-ethylthio-1H-tetrazole significantly enhances the synthesis quality and yield of oligoribonucleotides. RNA synthesized using these improvements has been shown to be biologically active by a comparative ribozyme-substrate assay.

Plant cell adhesion to polymer surfaces as predicted by a thermodynamic model and modified by electrostatic interaction

A thermodynamic model of particle adhesion from a suspension onto a surface considers the roles of the solid surface tension (γ sv), the liquid surface tension (γ tv) and the cellular surface tension (γ cv). The model was used to describe the initial phases of adhesion of cultured plant cells of Catharanthus roseus maintained in suspending-liquids of various surface tension to the polymer substrates fluorinated ethylene propylene (γ sv = 16.4 mJ m −2), polystyrene (γ sv = 25.6 mJ m −2), polyethylene terephthalate (γ sv = 47.0 mJ m −2) and sulphonated polystyrene (γ sv = 66.6 mJ m −2). The extent of adhesion decreased as a function of increasing γ sv when γ lv > γ cv; however, adhesion increased with increasing γ sv when γ lv < γ cv. In essence, adhesion is more extensive to hydrophobic surfaces (i.e. polymers with a low surface tension) than to hydrophilic surfaces when the surface tension of the cells is less than the surface tension of the suspending-medium. These results are consistent with theoretical predictions. The cellular surface tension was determined, by contact angle measurements and adhesion experiments, to have a value of approximately 53 (±3) mJ m −2 and was modulated as determined by sedimentation volume analysis during the growth cycle of the plant cells. An electrostatic repulsion-van der Waals attraction mechanism explains the initial adhesion of suspension cultured plant cells to polymers immersed in liquids of various surface tension and ionic strength. The surface tension of distilled water was lowered from 72.5 to 44.5 mJ m −2 by addition of 1-propanol; at some γ lv intermediate between these two values this is expected to reduce the van der Waals attraction between cells to zero. Adhesion to surfaces was reduced in the presence of low van der Waals attraction and relatively high negative cell surface potentials. The negative cell surface potential was reduced and neutralized by addition of plurivalent cations. The influence of suspending-liquid ionic strength in solutions of NaCl, CaCl 2 and AlCl 3 was examined. The electrophoretic mobilities of the cells, as determined by microelectrophoresis, were reduced by increased ionic strength of the suspending-liquid, and the electrophoretic mobility was reduced increasingly as a function of increasing cation plurivalence. Increased cellular adhesion was recorded in response to decreased electrophoretic mobility induced by increased ionic strength. Adhesion was most extensive when the cells were bathed in a solution of 0.1 M AlCl 3; adhesion decreased with further increases in ionic strength until the negative cell surface potential was neutralized and charge reversal occurred. Suspending-liquids of up to 1.0 M CaCl 2 also resulted in increased cellular adhesion to all surfaces but charge reversal was not observed. These results conform to predictions of the DLVO theory. Adhesion in all test solutions demonstrated the paramount influential role of γ sv, γ lv and γ cv in controlling the initial phases of the plant cell adhesion process in accordance with thermodynamic model predictions; electrostatic repulsive interactions serve to modify the extent of plant cell adhesion to the surfaces. The process of plant cell adhesion is controlled by the interaction between interfacial tensions and electrostatic phenomena in the system.

Plant cell adhesion to polymer surfaces as predicted by a thermodynamic model and modified by electrostatic interaction

A thermodynamic model of particle adhesion from a suspension onto a surface considers the roles of the solid surface tension (γ sv), the liquid surface tension (γ lv) and the cellular surface tension (γ cv). The model was used to describe the initial phases of adhesion of cultured plant cells of Catharanthus roseus maintained in suspending-liquids of various surface tension to the polymer substrates fluorinated ethylene propylene (γ sv=16.4 mJ m −2), polystyrene (γ sv=25.6 mJ m −2), polyethylene terephthalate (γ sv=47.0 mJ m −2) and sulphonated polystyrene (γ sv=66.6 mJ m −2). The extent of adhesion decreased as a function of increasing γ sv when γ lv>γ cv; however, adhesion increased with increasing γ sv when γ lv<γ cv. In essence, adhesion is more extensive to hydrophobic surfaces (i.e. polymers with a low surface tension) than to hydrophilic surfaces when the surface tension of the cells is less than the surface tension of the suspending-medium. These results are consistent with theoretical predictions. The cellular surface tension was determined, by contact angle measurements and adhesion experiments, to have a value of approximately 53 (±3) mJ m −2 and was modulated as determined by sedimentation volume analysis during the growth cycle of the plant cells. An electrostatic repulsion-van der Waals attraction mechanism explains the initial adhesion of suspension cultured plant cells to polymers immersed in liquids of various surface tension and ionic strength. The surface tension of distilled water was lowered from 72.5 to 44.5 mJ m −2 by addition of 1-propanol; at some γ lvintermediate between these two values this is expected to reduce the van der Waals attraction between cells to zero. Adhesion to surfaces was reduced in the presence of low van der Waals attraction and relatively high negative cell surface potentials. The negative cell surface potential was reduced and neutralized by addition of plurivalent cations. The influence of suspending-liquid ionic strength in solutions of NACl, CaCl 2 and AlCl 3 was examined. The electrophoretic mobilities of the cells, as determined by microelectrophoresis, were reduced by increased ionic strength of the suspending-liquid, and the electrophoretic mobility was reduced increasingly as a function of increasing cation plurivalence. Increased cellular adhesion was recorded in response to decreased electrophoretic mobility induced by increased ionic strength. Adhesion was most extensive when the cells were bathed in a solution of 0.1 M AlCl 3; adhesion decreased with further increases in ionic strength until the negative cell surface potential was neutralized and charge reversal occurred. Suspending-liquids of up to 1.0 M CaCl 2 also resulted in increased cellular adhesion to all surfaces but charge reversal was not observed. These results conform to predictions of the DLVO theory. Adhesion in all test solutions demonstrated the paramount influential role of γ sv, γ lv, and γ cv in controlling the initial phases of the plant cell adhesion process in accordance with thermodynamic model predictions; electrostatic repulsive interactions serve to modify the extent of plant cell adhesion to the surfaces. The process of plant cell adhesion is controlled by the interaction between interfacial tensions and electrostatic phenomena in the system.

Thermodynamic investigation of monoclonal antibody alkylated nucleoside interaction as a model for epitope recognition on nucleic acids

The objective of this investigation is examination of the dominant forces that govern complex formation between a series of monoclonal antibodies directed against O6-ethyl-2'-deoxyguanosine. These monoclonal antibodies (coded as ER-6, ER-3, and EM-1) provide the basis for a thermodynamic comparative evaluation of the potentially different forces that stabilize the various monoclonal antibody (mAb) alkylated nucleoside complexes. The binding affinities of ER-6, ER-3, and EM-1 are measured in terms of specific (O6-ethyl-2'-deoxyguanosine, or O6-EtdGuo) and nonspecific (O6-methyl-2'-deoxyguanosine, or O6-MedGuo) antigens, under a variety of experimental conditions, including pH, sodium chloride addition, 1-propanol addition, and temperature, via a nitrocellulose affinity filter assay. The binding isotherms were analyzed via a least-squares routine fit to a two independent binding sites model. The temperature dependence of the van't Hoff enthalpies for the specific O6-EtdGuo interaction ranges from -15.18 to -18.60 kcal mol-1, while for O6-MedGuo the range was extended from -2.72 to -20.66 kcal mol-1. The standard and unitary entropies were negative for those mAb interactions with O6-EtdGuo as well as for ER-6/O6-MedGuo complex formation. However, it was found that the interactions between ER-3 and EM-1 with O6-MedGuo led to decidedly positive entropic values. These results indicate two different dominant forces at work in complex stabilization. The interaction of the three mAb's with their specific antigen, as well as ER-6/O6-MedGuo interaction (nonspecific), may well be controlled by van der Waals type forces, while ER-3 and EM-1 interactions with nonspecific antigen imply formal charge neutralization electrostatics as the dominant force.

The Effect of Organic Additives on the Thermodynamic Parameters of Micellization

Abstract The CMC values of dodecylammonium chloride and iodide and of hexadecylammonium chloride were measured in water upon the addition of acetone, 1-propanol, and urea at several temperatures. The effects of the additives were most remarkable on the CMC of hexadecylammonium chloride at 45.0 °C. Urea was less effective on the disruption of micelles than acetone, while the addition of 1-propanol was most effective. The enthalpy of micellization became more negative, while the entropy of micellization became less positive, as the additive concentration increased. We divided the standard free energy of micellization into the hydrophobic term, ΔG°n, and the hydrophilic term, ΔG°p. The value of ΔG°p became more negative with the additive concentration and contributed to the stabilization of the micelle, while ΔG°n became less negative. Therefore, it was concluded that the disruption of the micelle in the presence of these organic additives results from an increase in the free energy in the hydrophobic group of the surfactant molecule.