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The object of this study is multicomponent heterogeneous liquid-liquid system with n-amyl acetate synthesis reaction. New experimental data on solubility, liquid-liquid equilibrium (LLE) and critical compositions for acetic acid – n-amyl alcohol – n-amyl acetate – water at 303.15 K and atmospheric pressure are presented. Solubility and critical states were investigated by “cloud-point technique” and pale opalescence blue methods accordingly. LLE compositions were determined by gas chromatography and correlated by NRTL model. Results calculated using NRTL modeling are in sufficient agreement with experimental data. Standard deviations for binary, ternary subsystems do not exceed 0.45% and for quaternary system investigated – 0.53%.

Solubility of the quaternary system acetic acid – n-amyl alcohol – n-amyl acetate – water was investigated at 293.15 K, 303.15 K, 313.15 K, 323.15 K and atmospheric pressure. Binodal curves and binodal surfaces were determined using isothermal titration (cloud-point technique) and presented in composition simplices including 3D phase diagrams in composition tetrahedron. Binary mixtures were carried out by the gas chromatography method. Experimental data were predicted using UNIFAC model, and it was found that the calculating results of liquid–liquid equilibria (LLE) are in inconsistent agreement with the experimental data on solubility at all temperatures.

This paper presents a preliminary experimental study on the combustion and emission characteristics of Dual Fuel Sequential Combustion (DFSC) mode, in which port fuel injection of n-heptane combined with in-cylinder, directly injected ethanol, n-butanol and n-amyl alcohol are used in a single-cylinder engine at fixed directly injection timing. The results show that the heat release can be divided mainly into three stages: low temperature reaction, high temperature reaction of n-heptane and the directly injected fuel combustion stage. The amount of port injected n-heptane plays a key role in the maximum in-cylinder pressure (Pmax), maximum in-cylinder mass averaged temperature (Tmax) and the maximum pressure rise rate. For the high overall lower heating values (LHVs) per-cycle, the CO emissions decrease with the increase of the premixed ratio. By contrast, the CO emissions increase with the premixed ratio when the overall LHVs per-cycle are kept at medium and low levels. The NOx and soot emissions are all kept at low levels for the experimental conditions. In particular, the higher latent heat, lower cetane values and the shorter carbon chains associated with ethanol lead to lower NOx and soot emissions than those of n-butanol and n-amyl alcohol. When directly injection of n-butanol and at low loads, with optimized premixed ratio, the indicated thermal efficiency can be higher than 46% meanwhile maintaining low emissions.

This paper presents an experimental study on combustion and emissions characteristics of reactivity controlled compression ignition (RCCI) combustion in which in-cylinder directly injected n-heptane combined with port injection (PI) of ethanol, n-butanol and n-amyl alcohol are used in a single-cylinder engine. The results show that when the overall lower heating values (LHVs) per-cycle is constant, with the increase of premixed ratio (RP), nitrogen oxides (NOx) and soot emissions decrease. When in high overall LHVs per-cycle, NOx and soot emissions of ethanol, n-butanol and n-amyl alcohol RCCI are also high. Meanwhile, compared to n-heptane/n-butanol and n-heptane/n-amyl alcohol, the combustion phases of ethanol RCCI are strongly delayed at high premixed ratio. For certain premixed ratios and overall LHVs per-cycle, low NOx and soot emissions can be realized when fueled with ethanol.

The Piezoelectric Quartz Crystal Microbalance (QCM) method was used to measure the solubilities of n-amylalcohol in poly (n-butyl methac1ylate) and polyisobutylene at temperatures of 333.15 K, 353.15 K and 353.15 K. The crystals used were 5 MHz, AT-Cut, 5.5 mm in diameter and 0.3 mm in thick. Reliability of the measurements was comfirmed by comparing the present data with the literature data for the system of benzene-polyisobutylene at temperature 338.15K. The solubilities n-amyl alcohol in polyisobutylene were undectedable in the range of temperature experiments by the present apparatus because of the low solubility. For the solubilities of n-amyl alcohol in ploy (n-butyl methacryalate) the higher temperature, the lower solubility and the experimental data could be correlated by the UNIQUAC equation with average absolute deviation between experimental and calculated solvent activities of 3.8%. Keywords: Solubility, Quartz Crystal Microbalance, Solvent, Polymer Abstrak Dalam penelitian ini, metode Piezoelectric Quartz Crystal Microbalance (QCM) digunakan untuk mengukur kelarutan pelarut n-amylalkohol dalam polimer poly (n-butyl methacrylate) dan polyisobutylene pada temperatur 333,15 K, 343,15 K dan 353,15 K. Kristal yang digunakan adalah jenis AT-Cut 5 MHz, diameter 5,5 mm dan ketebalan 0,3 mm. Reliabilitas dari pengukuran di tes dengan membandingkan hasil pengukuran dengan data literatur untuk sistem benzene­polyisobutylene pada temperatur 338, I 5K. Kelarutan n-amyl alkohol dalam polyisobutylene tidak dapat terdeteksi pada range temperatur eksperimen dengan peralatan yang ada karena kelarutannya rendah. Untuk kelarutan n-amylalkohol dalam poly(n-butyl methacrylate), semakin besar suhu, kelarutannya semakin rendah dan data eksperimen dapat dikorelasikan menggunakan persamaan UNIQUAC dengan rata-rata deviasi ahsolut sebesar 3,8%. Kata Kunci: Kelarutan, Quartz Crystal Microbalance, Pelarut, Polimer

This investigation deals with the studies on the effect of the nature and concentration of surface active substances (s.a.s) on the a.c. reduction peaks of Cd3+ and Zn3+ ions and vice-versa by a.c. polarography. The magnitude of the reduction peak is not influenced up to a certain concentration of the s.a.s., but with concentrations higher than this, the magnitude of the reduction peak progressively decreases; a concentration of 1.3% of n-amyl alcohol completely removes the 10−3M Cd2+ peak. Neither magnitude nor the peak potential of the tensammetric peak of n-amyl alcohol are influenced by the presence of Cd2+ ions. There is a linear relation between the concentration of the electroactive species and the optimum concentration of the s.a.s., and also the concentration of the s.a.s. just required to remove the reduction peak. These observations are further supported by the curve which gives the linear relation between the concentration of the electroactive species and the amount of the s.a.s. required to reduce the magnitude of the reduction peak to half its value. The amount of the surfactants required to remove the reduction peak completely is in the order n-amyl alcohol > Cerfak [sodium napthalene (2-dodecyl)3-sulphonate] > cetylpyridinium bromide. These results are discussed.

Dependences of boundary tension and capacitance at the mercury-aqueous 0.1N HClO/sub 4/ interface on polarization and organic solute concentration were determined for the solutes n-amyl alcohol and phenol. The surface charge density at fixed polarization varied linearly with surface excess in the case of n-amyl alcohol, but contained both linear and cubic terms in surface excess in the case of phenol suggesting a change in phenol orientation with increasing coverage. Near the electrocapillary maximum, the differential capacitance varied linearly with coverage in both cases. The theory of irference of adsorption from capacitance measurements is further discussed. It is pointed out that the thermodynamic'' inference based on double integration of non-static capacitance curves introduces (by integrating across desorption peaks) serious errors where solutes are strongly adsorbed at small concentrations. Criteria for estimating the errors thus introduced are suggested. An earlier treatment based on a (non- thermodynamic) assumption of linear variation of surface charge density with coverage appears adequately justified for inference of fractional surface coverages near the electrocapillary maximum, but must be considered approximate for evaluation of molar areas at full coverage in cases where linear variation of charge with coverage has not been demonstrated. (auth)

The dielectric constant in the Helmholtz double layer has been calculated from measurements of interfacial tension and metal-deposition potential on mercury in the presence of ethylmethyl-ketone and n -amyl alcohol. The results show that the adsorption of ethylmethylketone, a small polar molecule, does not affect the dielectric constant appreciably, but n -amyl alcohol, which is adsorbed with its hydrocarbon tail within the Helmholtz double layer, lowers the dielectric constant.

A procedure was developed for determining chromium(VI) in the soil organic fraction; it consisted of three steps: the preparation of a soil solution; the isolation and separation of chromium(VI) and chromium(III); and the determination of chromium(VI). Soil solutions were prepared by leaching soil samples with a Na4P2O7 solution (the Rudd method). Chromium(VI) was extracted from the soil solution with a solution of sodium diethyldithiocarbamate in n-amyl alcohol; the conditions of the extraction and separation of chromium(VI) and chromium(III) were optimized. Chromium(VI) in solutions was determined after back extraction by spectrophotometry with diphenylcarbazide or by flame atomic absorption spectrometry. The procedure was validated using a reference soil sample, and the material balance of chromium in the systems under study was calculated.

This article investigates the influence factors of reagent ratio, pH, stirring intensity, sintering temperature along with ultrasonic wave to particle size, distribution of nanoziconium dioxide in recombination surfactant system. The optimized reagent ratio (wt) of cyclohexan, OP‐10, n‐Amyl alcohol, zircon salt solution are 55%, 17.5%, 17.5%, 10%, respectively. At pH=8.7, the size of nanozirconium oxide has the priority of smaller (

The possibility of applying headspace solvent microextraction (HSME) for determination of mononitrotoluenes (MNTs) in waste water samples is demonstrated. A drop of n-amyl alcohol containing naphthalene as an internal standard was suspended from the tip of a microsyringe needle over the headspace of stirred sample solutions for a predescribed extraction period. The drop was then injected directly into a gas chromatograph. Optimization of experimental parameters such as the nature of extracting solvent, microdrop and sample volumes, sampling temperature, stirring rate, ionic strength of the solution, pH and extraction time on HSME efficiency were investigated. Then enrichment factor, dynamic linear range (DLR), limit of detection (LOD) and precision of the method were evaluated by water samples spiked with MNTs. Finally, the method was successfully applied to the extraction and determination of the mononitrotoluenes in waste waters of both P.C.I. Company and Research Center of Azad University.

The influence of microemulsion electrokinetic chromatography (MEEKC) operating conditions, such as the type of water-immiscible alcohol, aqueous phosphate buffer concentration, pH, as well as the addition of methanol and 2-propanol, on acrylamide migration has been studied. These parameters have been optimized taking into account the presence of matrix signals, in order to avoid the interference of these peaks in acrylamide determination. The best separations were achieved using a microemulsion consisting of 0.8% m/v n-amyl alcohol, 3.3% m/v sodium dodecyl sulfate (SDS), 6.6% m/v 1-butanol, and 89.3% m/v 40 mM phosphate buffer at pH 6.5 working at 15 kV in uncoated silica capillaries. Linear calibration curves over the range studied (1.25-125 microg x mL(-1)), the detection limit (0.70 microg x mL(-1)), and both run-to-run (up to 3.4% for concentration and 1.6% for time values) and day-to-day precision (lower than 11.6% for concentration) have been established. Finally, the applicability of the MEEKC method developed has been demonstrated by analyzing levels of acrylamide present in samples of home-made French fries.

The change in refractive index with temperature has been determined at atmospheric pressure for water, methanol, ethanol, 1-propanol, 1-butanol, n-amyl alcohol, pentane, hexane, heptane, octane, nonane, decane and four different kinds of dimethyl silicone oil from about 2 to 80°C. All measurements were made using the D spectrum of the natrium line (wavelength : 589.3 nm). Liquid sample was boxed in a small Pyrex container in order to prevent evaporation of test liquid during measurement. The Pyrex container was set into an Abbe refractometer. The measured refractive index for the length of 589.3 nm was transferred to that to the wavelength of 632.8 nm using dispersive power. The data of refractive index vs. temperature were fitted to a second-degree poloynomial. By differentiating tese equations with temperature, thermooptic coefficients dn/dT were obtained over the range of temperature. Estimated maximum error in the thermooptic coefficient is within 3%.

A highly sensitive and selective method has been proposed for direct speciation determination of trace amounts of chromium in water samples using quercetin. The method is based on mixing 5 mL of diluted quercetin solution dissolved in n-amyl alcohol with 5 mL of acidic solution (pH 1) of Cr(VI), which is accomplished with luminescence quenching of the organic phase due to partially oxidation of quercetin content. Cr(VI) is determined by measuring the diminished content of quercetin with spectrofluorometric method (lambda(ex)=276 nm, lambda(em)=331 nm). After oxidation of the Cr(III) content to Cr(VI) and determination of the total chromium as Cr(VI), the Cr(III) is obtained by subtracting. All the variables were studied in order to optimize the reaction conditions. No considerable interference was observed due to the presence of co-existing anions and cations. The calibration graphs were linear in the range 1.0 x 10(-7) to 2.0 x 10(-6)M with the detection limits of 9.1 x 10(-9)M. The R.S.D. obtained for 1.0 x 10(-6)M of Cr(VI) was 1.7% (n=7). Validation of the measurements was confirmed using standard reference materials. The method was applied to determine the chromium species in natural water samples. The recoveries obtained for the spiked amount of chromium species were >98%, which denote on satisfactorily application of the method.

The extraction of gold(III) from nitric acid solutions by means of oxygen-containing solvents (di-isopropyl, diethyl and dichloroethyl ethers, methyl isobutyl and methyl isopropyl ketones, n-amyl acetate and n-amyl alcohol) is described. The most effective of these extractants are di-isopropyl ether (in the range 5.5–10 M nitric acid) and diethyl ether (4–10 M nitric acid). In both cases, maximum extraction is ca. 95% in a single pass. Salting-out agents (ammonium, magnesium and aluminum nitrates) have little effect on the extraction of gold(III) with di-isopropyl ether. Uranium(VI), thorium(IV), cerium(IV) and chromium(VI) are extracted to different degrees with di-isopropyl ether under the optimal conditions for gold (7 M nitric acid). The method for extracting gold from strong nitric acid medium with di-isopropyl ether is applied in the analysis of anode copper and copper concentrate.

Structural changes in the chloroplast membranes caused by acidification and heat-treatment are studied by observing the changes in the fluorescence of ANS bound to thylakoid membranes. On addition of acids to buffered suspension of isolated pea chloroplasts, the fluorescence intensity of bound ANS shows a sigmoidal rise on reaching a pH value of about 4.5. A part of the fluorescence enhancement of bound ANS brought about by protons is not reversible on back titration with alkali. The reversible part of acid induced rise in ANS fluorescence possibly reflects structural changes expected to be associated with photophosphorylation. Divalent cations enhance the fluorescence of ANS bound to chloroplasts between a pH range 4.5–7.0 but diminish it if the pH is below 4.5. Addition of acid to heat-treated chloroplasts shows similar sigmoidal rise in ANS fluorescence intensity on lowering the pH to about 4.5. On addition of acid upto a pH of 3.1, the ANS fluorescence is greater than that of untreated chloroplasts, however, at pH below 3.1, the fluorescence of bound ANS is lower than the control chloroplasts. This observation indicates that heat-treatment caused some alteration of the microstructure of thylakoid membranes of chloroplasts besides the usual loss in the O2 evolving capacity. This is further confirmed from the studies of Hill-activity and ANS binding to chloroplasts incubated at various temperatures in the absence and presence of aliphatic alcohol. Hill-activity (DCPIP reduction) of chloroplasts incubated at temperatures between 25‡ C and 55‡ C first increases reaching a maximum at 45‡ C and then declines rather sharply, when the chloroplasts are heated beyond 45‡ C (Tmax). The presence of 200 mM n-butyl alcohol or 40 mM n-amyl alcohol during the warming treatment lowers the temperature by 8‡ C at which the decline in the Hill-activity is observed. An enhancement in the fluorescence intensity and a blue shift of the emission spectrum of bound ANS are noted if the chloroplasts are heated beyond the Tmax either in absence or presence of alcohol. The changes in the fluorescence of ANS bound to heat-treated chloroplasts plausibly reflect the nature of the structural changes in chloroplasts during the heating upto 55‡ C.

Prior work on low energy surfaces has suggested that the adsorbed film is submonolayer at saturation pressure in those cases for which the liquid phase of the adsorbate vapor exhibits a finite contact angle on the solid surface. This study reports on the modification of particulate quartz by high temperature- and pressure-induced esterification of surface hydroxyl sites with n -amyl alcohol and with 2,2,2-trifluoroethanol and on subsequent vapor adsorption studies using n -octane, benzene, and carbon tetrachloride as adsorbates. The adsorption data were analyzed in the two-dimensional van der Waals model framework. Spreading pressures at saturation vapor pressure ranging from 5 to 7.2 erg/cm 2 were obtained with surface coverages near one-half monolayer. The values are compared with those obtained from various treatments of data provided by other experimental techniques.

The extraction of Pa(V) from 1M perchloric acid medium with HDEHP in toluene was carried out. The different factors affecting the metal distribution coefficient such as HDEHP concentration in the organic phase, pH of the aqueous phase and the equilibrium temperature were followed. From the data obtained the equilibrium constants of the extraction reaction were calculated. From the temperature variation, the corresponding thermodynamic parameters (ΔG, ΔH and ΔS) were also derived. In the same way, the effect of addition of some N-and 0-containing solvents such as pyridine, 2,2′-dipyridyl, n-amyl alcohol, n-decyl alcohol and n-butyl acetate, to the HDEHP organic phase was demonstrated. From the data obtained the suggested mechanisms for the synergistic extraction reactions were discussed together with the corresponding values of the thermodynamic parameters.

The influence of tensammetric waves on one another has been investigated by ac polarography. In most of the cases studied, the influence of the more negative tensammetric peak on the less negative peak is due to the greater adsorbability of the surfactant corresponding to the more negative peak on the electrode surface. Ionic surfactants are more efficient in suppressing the less negative tensammetric peak than are non-ionic ones. It is concluded that the effect can be used for comparing the adsorbability of various surfactants in aqueous solution. In some cases the influence is due to chemical interaction between two surfactants to form a complex which is more surface-active than the individual surfactants. It has been possible to estimate the composition of the complex between n-amyl alcohol and o-cresol as 1 : 2, by this technique.

For the determination of very low concentrations of copper in tin, an analytical method involving reactor neutron activation was developed whereby the copper activity was separated from the tin matrix by extraction of the Cu(I) cuproin complex in n-amyl alcohol. A new decontamination technique was sought in order to remove the copper contamination present on the tin surface. Pre-irradiation removal of the tin surface combined with post-irradiation etching appeared to be the most efficient.

Due to abnormally small root-mean-square end-to-end distances for poly(n-lauryl methacrylate) fractions in an ideal solvent reported previously, investigation of this polymer in another ideal solvent was carried out. Phase separation studies indicated that in n-amyl alcohol the θ-temperature is 29.5°C., and viscosity and light-scattering measurements were made in this temperature. Dimensions in this solvent were found to be in the expected range. K values in the two ideal solvents are compared.

The niobium and tantalum content of rocks, graphite, and stainless steel samples were determined by thermal neutron activation analysis with a 10-minute irradiation of samples in a neutron flux of 10/sup 12/ n cm/sup -2/ second/sup -1/ . Niobium and tantalum were separated simultaneously, followed by an extraction of niobium-free tantalum with 1-pentanol (n-amyl alcohol). The entire radiochemical separation was completed in less than 10 minutes. The radioactivity and half life of the chemically separated niobium-94m and tantalum- 182m were determined by gamma spectrometry. In practice, microgram amounts of niobium and tantalum can be determined simultaneously in 30 minutes by this method. (auth)

Selectivity coefficients of liquid-membrane electrodes for common inorganic anions were measured in electrodes containing tris(l,10-phenanthroline)iron(II), tris(4,7-diphenyl-1,10-phenanthroline)iron(II) or tetraheptylammonium ion in nitrobenzene, and tris(4,7-diphenyl-1,10-phenanthroline)iron(II) ion in nitrobenzene, chloroform or n-amyl alcohol as the liquid membrane. With the exception of the amyl alcohol electrode, selectivity coefficients were relatively independent of membrane composition and followed a common sequence of decreasing selectivity: PF6−> ClO4−>SCN−~I−~BF4−>NO3−>Br−>Cl−. This sequence parallels the order of increasing anion hydration energy, suggesting that aqueous phase solvation energies play a predominant role in determining electrode selectivity for these ions. Time-dependent behavior of liquid-membrane electrodes on transfer between solutions containing different ions also is described. Instantaneous e.m.f. readings were used to determine selectivity coefficients.

A spectrophotometric method for determining iron in the range 0.001 to 0.125% in high-purity niobium, tantalum, molybdenum, and tungsten metals is described. After sample dissolution and reduction of iron to the bivalent state with ascorbic acid and hydroxylamine hydrochloride, the red complex formed between iron(II) and bathophenanthroline (4,7-diphenyl-1,10-phenarthroline) is extracted into n-amyl alcohol and the absorbance of the resulting extract is determined at 536 m mu . Interference from copper is eliminated with thiourea. Cobalt, cadmium, nickel, manganese, and zinc also interfere, but the amounts of each of these impurities present in the four high-purity metals described are so low that their irterference effects are negligible in the proposed method. Higitly reproducible and precise results can be obtained with careful control of the pH during reduction and extraction. (auth)

A spectrophotometric method for determining 0.0005–0.125% of copper in high-purity niobium, tantalum, molybdenum and tungsten metals is described. After sample dissolution and reduction of copper to the univalent state with ascorbic acid, the yellow complex formed by copper I and bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) is extracted into n-amyl alcohol and the absorbance of the resulting extract is determined at 476 mμ. Other impurities present in the four high-purity metals described do not interfere in the proposed method.

In order to facilitate the analysis of nonvolatile organic acids by partition chromatography with silica, the relation of solvent composition to the rate of movement of the acids has been investigated. It was found that with chloroform, n-amyl alcohol, and dilute sulphuric acid the logarithm of the peak volume, and hence of the partition coefficient, is proportional to the logarithm of the alcohol concentration. The spread of the zones bears a direct linear relation to the peak volume. A simple graphical method is shown for planning a suitable solvent program for any particular set of acids. Stepwise elution is more suitable than a logarithmic gradient for this type of system.

The two-dimensional separation of DNP-amino acids by solvent systems which appear to overcome most of the shortcomings of previously described solvent systems is described. The organic solvent consists of n -amyl alcohol saturated with 0.05 M phthalate buffer at pH 6.0; the aqueous solvent consists of 1.5 M sodium sulfate containing 0.05 M phthalate buffer (pH = 6.0).