Showing papers on "Hexane published in 1982"
TL;DR: In this article, full-fat soyflakes are extracted with supercritical carbon dioxide (SC-CO2) at pressures of 3,000~10,000 psig and 50 C.
Abstract: Full-fat soyflakes are readily extracted with supercritical carbon dioxide (SC-CO2) at pressures of 3,000~10,000 psig and 50 C. Under these conditions, SC-CO2 has the density of a liquid and the diffusivity of a gas. Therefore, equilibrium solubility is readily achieved in a short-path batch extractor which permits high gas flow rates. Soybean oil extracted with SC-CO2 is lighter in color and contains less iron and about one-tenth the phosphorus of hexane-extracted crude oil from the same beans. The lower phosphorus content is reflected in a chromatographic refining loss of 0.6% compared to 1.9% for hexane crude. Refined oils from hexane and SC-CO2 extraction had equivalent odor and flavor scores initially and after 4 days' storage at 60 C. Carbon dioxide, an ideal solvent for extraction of food products, is low-cost and readily available from fermentation processes and could free over 20 million gallons of costly hexane per year for essential energy uses.
187 citations
TL;DR: In this article, the Prigogine-Flory theory of solution thermodynamics has been used to interpret molar excess volume data, V E, for two series of alkane mixtures: the five isomers of hexane mixed with normal hexadecane (Data from Reeder, et al.).
Abstract: The Prigogine-Flory theory of solution thermodynamics has been used to interpret molar excess volume data, V E , for two series of alkane mixtures: the five isomers of hexane mixed with normal hexadecane (Data from Reeder, et al.) and the five hexane isomers mixed with a highly branched hexadecane isomer, 2,2,4,4,6,8,8-heptamethylnonane (this work). Values of V E are negative and similar for both series, but vary considerably with the hexane within a series. According to the theory, V E contains a ‘P* contribution’ not found in the excess enthalpy and entropy, which depends strongly on the internal pressures and the derived P* parameters of the components. Values of V E are well predicted for both series, the variation of V E corresponding to the different internal pressures or P* parameters of the hexanes.
181 citations
126 citations
TL;DR: In this article, the transformation of n-hexane has been carried out under hydrogen pressure on a series of platinum-stabilized Y-zeolites with platinum contents varying from 0 to 17.7 wt% (platinum area ranging from 0, 10 m 2 g −1 ).
81 citations
TL;DR: In this article, the pathways of chlorinated benzenes and toluenes, hexachlorobutadiene and polychlorinated biphenyls in the environment capillary gas chromatographic methods have been developed for analysis of water, sediments and biological samples.
Abstract: In order to assess the pathways of chlorinated benzenes and toluenes, hexachlorobutadiene and polychlorinated biphenyls in the environment capillary gas chromatographic methods have been developed for analysis of water, sediments and biological samples. Compound recoveries are reported from water, using liquid-liquid extraction with hexane, and from sediments and fish, using soxhlet extraction with hexane/acetone. After suitable cleanup, hexane extracts are chromatographed on a duel fused silica column arrangement (OV1 and SE54 with electron capture detectors for quantitation. The application of these procedures to environmental analysis is discussed.
34 citations
TL;DR: In this article, a vitrinite concentrate of Taiheyio coat has been reacted with various alcohols using ZnCl2 as a catalyst under nitrogen pressure The reaction conditions such as the reaction time, reaction temperature, initial nitrogen pressure and the effect of other Lewis acids as catalysts have been examined using methanol.
32 citations
Patent•
27 Jul 1982
TL;DR: In this article, an energy-efficient improvement in a continuous deasphalting process is presented, in which a mixture of viscous hydrocarbon oils with resins and/or asphaltenes is contacted with a quantity of pure or mixed hydrocarbon solvents including, but not limited to, propane, butane, pentane, hexane, heptane, isomers thereof, and unsaturated hydrocarbons of similar molecular weights.
Abstract: The invention is an energy-efficient improvement in a continuous deasphalting process in which a mixture of viscous hydrocarbon oils with resins and/or asphaltenes is contacted with a quantity of pure or mixed hydrocarbon solvents including, but not limited to, propane, butane, pentane, hexane, heptane, isomers thereof, and unsaturated hydrocarbons of similar molecular weights, in order to separate a primary extract phase comprising high viscosity oil, resins and/or asphaltenes, and solvent. The primary raffinate phase is further contacted with an additional quantity of solvent comprising similar components to those in the primary solvent (but not necessarily identical thereto) to separate a secondary extract phase comprising high viscosity oil and solvent, and a secondary raffinate phase comprising resins and/or asphaltenes and solvent. The contacting step may be repeated as often as desired to make additional extract phases which are recovered separately. The solvents from the extract and raffinate phases are separated from the associated viscous oils, resins and/or asphaltenes, and reused in the contacting process. Several embodiments of the invention are disclosed. In each embodiment, the primary and secondary recovery systems are integrated so that heat recovered from the primary solvent is used to operate the secondary recovery system.
28 citations
20 citations
TL;DR: In this article, the adsorption behavior of dioctyldimethylammonium chloride at water/hexane interface has been studied by measuring the interfacial tension as a function of temperature and pressure at various bulk concentrations.
Abstract: The adsorption behavior of dioctyldimethylammonium chloride at water/ hexane interface has been studied by measuring the interfacial tension as a function of temperature and pressure at various bulk concentrations. By applying the thermodynamics of adsorption at interfaces to the experimental results, the thermodynamic quantity changes associated with adsorption and the interfacial density of dioctyldimethylammonium chloride have been evaluated.
20 citations
TL;DR: In this paper, a kinetic and synthetic study of the reaction of benzyl chloride with bromide ion has been performed in microemulsions composed of cetyltrimethylammonium bromides, 1-butanol, water, potassiumbromide, and hexane.
18 citations
TL;DR: In this paper, the intermolecular interactions between the carbonyl groups (CHO) are influenced by the intramolecular interaction between carbonyls and phenyl groups, particularly for the mixtures containing benzaldehyde.
TL;DR: In this article, the reaction of t-butyllithium with phenylmethylvinylchlorosilane at low temperature in hexane solvent gave a 48% yield of a mixture of the five isomers of the 1,3-diphenyl-1,3dimethyl-2,4-dineopentyl -1, 3-disilacyclobutanes, along with an acyclic isomer.
TL;DR: In this paper, the influence of reaction temperature, metal halide and alumina on the composition of the products was studied by gas chromatography, gel permeation chromatography (gpc), 1H solution and 13C solid state cross polarization (nmr) spectroscopy and optical microscopy.
TL;DR: The excess volumes of bicyclohexyl + n-pentane, + n -hexane, and +cyclopentane have been measured over the whole composition range at 283.15 and 298.15 K as mentioned in this paper.
TL;DR: In this paper, the effects of temperature on the liquid chromatography absorbance baseline were investigated in terms of wavelength and solvents, and possible mechanisms for this effect were discussed and include solvent impurity, density changes and inter-molecular bonding.
Abstract: This paper is concerned with our investigation into the effects of temperature on the liquid chromatography absorbance baseline. Measurements were made to quantify the effects in terms of wavelength and solvents. Five solvents commonly used in HPLC were investigated, methanol, propanol, hexane, heptane and acetonitrile. The alcoholic solvents were found to have a high absorbance sensitivity to temperature at wavelengths around their ‘UV cut off’ points. Possible mechanisms for this effect are discussed and include solvent impurity, density changes and inter-molecular bonding.
TL;DR: In this paper, a mechanism is proposed in which free radicals, once formed, either desorb from the surface or decompose further into smaller fragments and olefins, and the effects of temperature, pressure and surface treatment upon radical yields have also been investigated.
Abstract: Desorption of alkyl and alkenyl (methyl, ethyl, allyl, and propyl) radicals from hot surfaces in the low-pressure (1 x 10^(12) - 8 x 10^(12) molecules cm^(-3) catalytic decomposition of hexane over W (1100-1800 K) and Pt (850-1400 K) has been studied by modulated-beam mass spectrometry. Time-of-flight analysis (phase spectrometry) of reaction products provided direct evidence about their identity. The effects of temperature, pressure, and surface treatment upon radical yields have also been investigated. Trapping of reactive species with iodine in a tandem reactor confirmed the presence of alkyl radicals. A mechanism is proposed in which free radicals, once formed, either desorb from the surface or decompose further into smaller fragments and olefins.
TL;DR: In this article, the binary PTxy vapor-liquid equilibrium data for the benzene+hexane system were evaluated, and the needs for new experimental data were defined, as well as the criteria for new data.
Abstract: The binary PTxy vapor–liquid equilibrium data for the benzene+hexane system are evaluated. The needs for new experimental data are defined. Key words: activity coefficients; benzene; excess Gibbs function; hexane; vapor–liquid equilibrium.
TL;DR: In this paper, an alternative method for the analysis of coal-derived materials for oil, asphaltene and pre-asphaltenes content, is described, where the test sample is coated as a thin layer on the fine mesh glass beads and the relevant fractions are extracted sequentially with hexane, toluene and pyridine.
TL;DR: In this paper, evidence is presented to show that there is a correlation between the amount of unsaturation in polypropylene and its induction period during photo-oxidation, while doping the polymer with hexane extracts causes an increase in stability.
Journal Article•
TL;DR: Male Fischer rats were exposed repeatedly to high concentrations of hexane for 10 minutes in a pattern resembling human solvent abuse or to low concentrations of Hexane continuously for 8 or 24 hours daily, suggesting induction of liver microsomal enzymes synthesizing 2,5-HD from hexane.
Abstract: Male Fischer rats were exposed repeatedly to high concentrations of hexane for 10 minutes in a pattern resembling human solvent abuse or to low concentrations of hexane continuously for 8 or 24 hours daily. Concentrations of hexane in blood and brain were linearly related to the concentrations of hexane in the chamber after a 10-minute exposure, and declined thereafter, with half lives of about 2 1/2 and 4 minutes in blood and brain, respectively. Despite the rapid elimination of hexane, neurotoxic levels of 2,5-hexanedione (2,5-HD) were formed from repeated 10-minutes exposures to a high concentration of hexane when the interexposure interval was 20 minutes. Neurotoxic levels of 2,5-HD also resulted from continuous exposure to much lower concentrations of hexane. Both exposure schedules caused an increase in 2,5-HD concentrations in blood after repeated daily treatments, suggesting induction of liver microsomal enzymes synthesizing 2,5-HD from hexane. The minimal sustained plasma 2,5-HD concentration that will result in neurotoxicity appears to be less than 50 micrograms/ml in the rat.
TL;DR: Kimura et al. as discussed by the authors measured the excess enthalpies of 2-methyl-1-pentanol with hexane isomers and found a roughly linear correlation between the results for equimolar mixtures and the mean number of gauche conformations of the isomer.
TL;DR: In this article, a mixture of polymeric phosphazenes containing imino dichloro and imino bis(trifluoroethoxy)phosphoranetrietriyle units was investigated by 31P NMR.
Abstract: Hexakis(2,2,2-trifluorethoxy)cyclotriphosphazene (1b) reacts with borontrichloride at elevated temperatures to give a mixture of polymeric phosphazenes containing imino dichloro and imino bis(trifluoroethoxy)phosphoranetriyle units. The reaction was investigated by 31P NMR. Separation of several fractions of polymers was achieved by hexane/benzene solvent extraction. Molecular weights have been determined by means of membrane and/or vapor pressure osmometry. A reaction mechanism is discussed.
TL;DR: In this paper, the authors compared the properties of the resultant miscellae and meals for each sample and found that the mixture of hexane and acidic hexane improved the settling rates of marc particles, and that protein efficiency ratios, digestibility, epsilon amino-free lysine values and free and total gossypol contents were essentially identical.
Abstract: Cottonseed was extracted with hexane and acidic hexane (hexane that contained 2–25% acetic acid) and properties of the resultant miscellae and meals were compared for each sample. Pigment contents were only slightly larger in acidic hexane miscellae. Settling rates of marc particles were much faster through acidic hexane miscellae. Nutritional analyses of the extracted cottonseed meals indicated that protein efficiency ratios, digestibilities, epsilon amino-free lysine values and free and total gossypol contents were essentially identical with each type of solvent. Aflatoxin contents of similarly treated, contaminated peanuts did not change. The results are discussed with regard to previous findings concerning the more thorough extractions of lipid from oilseeds with acidic hexane than with hexane alone.
01 Jan 1982
TL;DR: In this paper, a detonation transition was measured by timing the change in light intensity of the reaction front and the measurement was supplemented by pressure detected by transducers along the tube.
Abstract: Mixtures of hexane with oxygen and heptane with oxygen have been initiated in a detonation tube by a controlled electric spark. The equivalence ratios investigated were 0.54 to 1.74 for hexane and 1 to 1.9 for heptane. Initial pressures investigated were 100–650 torr for hexane and 95–250 for heptane. Time and distance of deflagration to detonation transition (DDT) were measured as a function of the concentrations, initial pressures and spark energy. The occurrence of DDt was measured by timing the change in light intensity of the reaction front. The measurement was supplemented by pressure detected by transducers along the tube. Good agreement has been found between experiments and CJ calculations.
TL;DR: In this paper, the authors measured the excess enthalpies for binary mixtures of 2-ethyl-1-butanol with the five isomeric hexanes, and compared the results with previously published results for 1-hexanol and 2-methyl-1.pentanol with different hexane isomers.
TL;DR: In this paper, the experimental results were compared with those determined from the Wilson equation using parameters obtained from binary results for two quinary systems containing n-hexane + ethanol + methylcyclopentane + benzene and either + toluene or + methanol.
TL;DR: The amount of water and Ca2+ present in the hexane and ether extracts was determined under various conditions to better understand the composition of the rhodopsin-lipid complexes in the solvents and the extraction mechanism.
TL;DR: In this article, the products RCH2SC6F5 (R = Me, Ph, C 6F5S, C6F 5SCH2), Ph2CHSC6-F5, R3CSC6f5(R =Me, Ph) and RCOSC6f 5 (R=Me, Me, P, P) have been characterized and their spectra, particularly NMR spectra have been examined.
TL;DR: Fluorine chemical shifts are reported for water/oil/soap/butanol micro-emulsions in which the soap is potassium 11-(2,2, 2-trifluoroethoxy)undecanoate and the oil is 1-(2 2,2)-hexane or a mixture of this material with heptane.
Abstract: Fluorine chemical shifts are reported for water/oil/soap/butanol microemulsions in which the soap is potassium 11-(2,2,2-trifluoroethoxy)undecanoate and the oil is 1-(2,2,2-trifluoroethoxy)hexane or a mixture of this material with heptane. In many of the solutions the two fluorinated compounds appear to have identical microenvironments. This reinforces arguments presented recently by others to the effect that microemulsions do not always contain distinct oil-rich and water-rich domains separated by a well-defined interfacial layer.