Showing papers on "Hexane published in 1984"

Determination of hydrocarbon types in petroleum liquids by supercritical fluid chromatography with flame ionization detection

Abstract: Supercritical fluid chromatography using packed columns and carbon dioxide as the mobile phase provides an alternate to the fluorescent indicator adsorption method (FIA) for determining saturates, olefins, and aromatics in petroleum liquids boiling below 350/sup 0/C. Silica and silver nitrate impregnated silica columns are used in series. Standard deviation is in the 0.4 to 0.8 wt % range, depending on sample type. Unlike the FIA method, this technique is suitable for colored samples and for samples containing material lighter than hexane. The separation requires 4 min per sample.

Gossypol Removal and Functional Properties of Protein Produced by Extraction of Glanded Cottonseed with Different Solvents

Abstract: Cottonseed flakes were extracted with one of the following solvents: (A) hexane; (B) 1:1 mixture of 85% isopropanol and hexane; and (C) acetone followed by 1:1 mixture of isopropanol and hexane. Meal B had the lowest free gossypol content of 0.069%. The functional properties and the protein content of all the meals were similar. Ultracentrifugation did not reveal any change in the proportion of the protein fractions. Gel electrophoresis indicated minor differences.

Isomerization of alkanes over a palladium salt of heteropolyacid

Abstract: Palladium dodecatungstophosphate (Pd3(PW12O40)2) supported on silica is an active and selective catalyst for the isomerization of pentane and hexane in the presence of hydrogen. Thus, hexane could be isomerized in a flow system under atmospheric pressure over 90% selectivity at 483 K. The reaction proceeds in a dual-dunctional mechanism; palladium metal formed by the reduction of palladium(II), and protons, act as a hydrogenation-dehydrogenation catalyst and an olefin-isomerization catalyst, respectively.

Adsorption studies of n-Olefin/n-paraffin mixtures on X- and Y-zeolites. I. Comparison of liquid phase and vapor phase adsorption of hexane-1 and n-hexane on NaX-zeolite

Abstract: The adsorption of hexene-1/ n -hexane mixtures of liquid solution on an NaX-zeolite ( Si Al = 1.4 ) was studied. The excess isotherms and the heats of immersion were determined on this zeolite. The difference between the molar heats of immersion determined from the temperature dependence of the surface excess is −32.4 kJ/mole the comparable value obtained by calorimetric method is −33.4 kJ/mole. A detailed thermodynamic analysis of these data showed an ideal behavior of hexene-1/ n -hexane in the bulk phase and adsorbed phase. A thermodynamic consistency test for the adsorption of liquids and their vapors was applied to our system.

Electrophoretic Mobility Of Oil Drops In The Presence Of Solvent Extraction Reagents

Abstract: The electrophoretic mobility (EM) of hexane and toluene droplets dispersed in aqueous solution has been investigated as a function of pH in the presence and absence of 5,8-diethyl–7–hydroxy–6–dodecanone oxime (the active extractant in the Henkel reagent, LIX63), Dinonylnaphthalene sulfonic acid (HDNNS), di(2-ethylhexyl) phosphoric acid (HDEHP) and tricaprylyl methyl ammonium chloride (Aliquat 336) Both hexane and toluene droplets were found to be negatively charged at pH > 3, with the absolute EM increasing with pH; the toluene droplets were more negatively charged than the hexane droplets The hydroxyoxime reagent had no significant effect on the EM, whereas the addition of HDNNS and HDEHP dramatically enhanced the negative charge at the organic/ water interface In the presence of 1·5 × 10−4 kmol m−3 Aliquat 336, the organic drops became less negatively charged and eventually acquired a positive charge at pH < 9 The results are explained In terms of the preferential adsorption of the aqueous

Adsorption of hydrocarbons on air-reacted activated carbons. I: Adsorption isotherms

Abstract: The adsorption of several hydrocarbons (benzene, cyclohexane, n-butane, n-hexane, 2,2-dimethylbutane and isooctane) on a series of carbons resulting from the reaction of an activated carbon prepared from almond shells with air at 623 K is discussed. The results are parallel to those obtained with N2 at 77 K (González-Vilchez et al. 1979) but very different to those of CO2 at 273 and 298 K (Rodríguez-Reinoso et al. 1984). A comparison of three different ways of expressing the adsorption data is used to discuss the possible molecular sieving effect of the carbons towards the hydrocarbons.

High temperature adsorption of hydrocarbons by activated carbons prepared from olive stones

Abstract: The evolution of microporosity of activated carbons prepared from carbonized olive stones as a function of burn-off in carbon dioxide (activating agent) has been studied at high temperature using a gas chromatographic technique. The specific net retention volumes have been used to determine the possible molecular sieve properties of the carbons towards several hydra-carbons. This molecular sieving is thought to be due to the existence of slit-shaped pores in the carbons with well-defined dimensions. The retention data have also been used to calculate the heats of adsorption and their dependence on the porosity of the carbons.

Oxidative losses of anthracene, acenaphthylene, and benzo(a)pyrene during Florisil and silica gel cleanup using diethyl ether containing peroxides

Abstract: In the analysis of samples for nonpolar trace organic compounds, a cleanup procedure is often required to remove interfering compounds. Columns of Florisil (magnesium silicate) and silica gel (silicic acid, SiO/sub 2/ x H/sub 2/O) are frequently used for this purpose. Occasionally, the occurrence of unexpected and undesired processes may be detected and eliminated before the modification is incorporated into ongoing analytical protocols. This paper describes such an experience involving acenaphthylene, benzo(a)pyrene, anthracene, and anthracene-d/sub 10/. The last compound has been recommended for use as an internal standard (IS) compound. Toward the goal of the development of a cleanup method which would allow the recovery of a range of neutral compounds following the extraction of filters used to sample ambient air, Florisil column chromatography was tested using solvent mixes of pentane and diethyl ether. Hexane:diethyl ether has been recommended for use in the cleanup of pesticide-containing extracts. Pentane was substituted here for hexane because of its greater volatility. It was hoped that the pentane:diethyl ether solvent mix ratio could be adjusted to allow the simultaneous recovery of the PAH compounds in the same eluant fraction. Recovery studies were carried out using a standard solution of pesticides and PAHs.

Solubilization of n-heptane-n-hexane and n-hexane-methyl methacrylate mixtures in aqueous surfactant solutions

Abstract: Binary mixtures of n -heptane- n -hexane and n -hexane-methyl methacrylate have been solubilized in aqueous solutions of cetyl trimethylammonium chloride and sodium dodecyl sulfate. It is observed that, while the amount of each component of the n -heptane- n -hexane mixture solubilized is proportional to their mole fraction in the organic mixture, a noticeable sinergistic effect is observed for the n -hexane-methyl methacrylate mixture.

Nitrogen solubility and vapor pressure of binary mixed solvents containing benzene, carbon tetrachloride, cyclohexane and 1-hexane

Abstract: Experimental data are presented for vapor pressure and nitrogen solubility at 25 °C for three binary nonpolar mixtures: cyclohexane + 1-hexane, cyclohexane + carbon tetrachloride and benzene + carbon tetrachloride. The one-fluid van der Waals model with the Carnahan-Starling equation for a reference fluid expression is applied to represent three thermodynamic excess quantities: the excess Gibbs energy, the excess molar volume and the excess quantity of gas solubility. It is found that agreement of the theory and the experiments is fairly good for mixtures of relatively globular molecules of benzene, cyclohexane and carbon tetrachloride. However, disagreement is found for mixtures of cyclohexane + 1-hexane.

HEXANE EXTRACTION-SPECTROPHOTOMETRY OF BISMUTH(III) WITH ο,ο'-DIETHYLDITHIOPHOSPHATE

Abstract: Bismuth(III) was extracted quantitatively into hexane from the aqueous phase containing 1 mmol dm-3 ο, ο'-diethyldithiophosphate(dtp-) at pH 0-4, and determined at 325 nm(e=1.51×104mol-1dm3cm-1) or 395 nm(e=4.09× 103mol-1dm3cm-1). The species extracted was [Bi(dtp)3] and the extraction constant for this complex was determined as 2.0×1018(mol dm-3)-3.

Azeotrope-like compositions of trichlorotrifluoroethane, acetone, nitromethane and hexane.

Abstract: Azeotrope-like compositions comprising of trichlorotrifluoroethane, acetone, nitromethane and hexane are stable and have utility as degreasing agents and as solvents in a variety of industrial cleaning applications.

Phenylthioglycolic acid derivative and its preparation

Abstract: NEW MATERIAL:The compound of formula I (R 1 is acyl or H; X is Cl or Br). EXAMPLE: 5-(N-Acetylamino)-2-chloro-4-fluorophenylthioacetic acid. USE: A synthetic intermediate of herbicide. PREPARATION: The compound of formula I can be produced by reacting the benzenethiol derivative of formula II with the haloacetic acid of formula YCH 2 COOH (Y is Cl or Br) in the presence of a dehydrohalogenation agent (e.g. pyridine, NaOH, etc.) in a solvent such as hexane, benzene, etc. at 0W100°C for 0.5W24hr. The amount of haloacetic acid and dehydrohalogenation agent is 1.0W 1.2 equivalent each per 1 equivalent of the compound of formula II. COPYRIGHT: (C)1985,JPO&Japio

Analyzing method of oil content in waste water

Abstract: PURPOSE:To vaporize hexane used for extracting oil in waste water by a simple means in a short time by blowing the air, and replacing the gas above a hexane evaporation vessel to promote vaporization of the hexane. CONSTITUTION:Oil and hexane extracted from waste water are contained in an evaporation vessel 1 and set in a room surrounded by hot plates 2. The temp. of the atmosphere is regulated to 80+ or -5 deg.C. A hot air supply pipe is provided above the evaporation vessel 1, and the hot air at 80+ or -5 deg.C is blown to the evaporation vessel 1 to vaporize hexane. The oil remaining in the evaporation vessel 1 is taken out to weigh, and the oil concentration is calculated. The time required for vaporization is decreased remarkably, and the analysis operation can be carried out rapidly.