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Showing papers on "Hexane published in 1989"


Journal ArticleDOI
TL;DR: In this article, the contents of free, esterified and insoluble-bound phenolic acids of meals produced by methanol-ammonia-water/hexane treatment of canola seed were determined and compared with those of hexane-extracted meal.

212 citations



Journal ArticleDOI
TL;DR: In this paper, the gas flow-cold trap method combined with surfactants was found to be effective in stabilizing ultrafine metal particles in solvents with a low dielectric constant.
Abstract: Metal fine particles are not dispersed at all in pure solvents with a low dielectric constant, such as hexane. The gas flow-cold trap method combined with surfactants was found to be effective in stabilizing ultrafine metal particles in solvents with a low dielectric constant. Ultrafine gold particles can be stably dispersed in hexane in a colloidal state by this method. It was found that the stabilizability of the colloid depends on the ionic types of the surfactant. Thus, a cationic surfactant such as dimethyldioctadecylammonium chloride (DOAC) shows good dispersibility, whereas an anionic surfactant such as 1,2-bis(2-ethylhexyloxycarbonyl)ethanesulfonate (AOT) dose not. The optical spectra of colloid solutions suggest a difference in the local colloidal state between two types of surfactants. Colloidal solutions of a gold fine particle/DOAC/hexane system are so stable against heating or drying that the solvents are easily substituted.

61 citations


Journal ArticleDOI
TL;DR: Propene was polymerized with ethylene bis(-1-indenyl)-dichlorozirconium (Et(Ind)2ZrCl2) and methylalumoxane (MAO) at 70°C as discussed by the authors.
Abstract: Propene was polymerized with ethylene bis(-1-indenyl)-dichlorozirconium (Et(Ind)2ZrCl2) and methylalumoxane (MAO) at 70°C. The polymer was fractionated by solvent extraction; there was no hexane insoluble material. The pentane insoluble, hexane soluble (C5iC6s) fraction contains 67% mmmm pentads. It has x-ray crystallinity of 59% comprised of 93% γ-phase, and no NMR detectable misinsertions. However, 1,3-insertion was found in the more soluble fractions.

42 citations



Journal ArticleDOI
TL;DR: An equimolar reaction of 2-hexyloxirane with carbon disulfide in hexane was run in the presence of triethylamine under 800 MPa at 100 °C for 20 h as discussed by the authors.
Abstract: An equimolar reaction of 2-hexyloxirane with carbon disulfide in hexane was run in the presence of triethylamine under 800 MPa at 100 °C for 20 h, and gave 63% of 4-hexyl-1,3-dithiolan-2-one (3a), ...

34 citations


Journal ArticleDOI
TL;DR: In this article, the influence of various extraction variables, i.e., the green coffee particle diameter, the mass ratio of ground coffee to solvent and the temperature, was studied.

33 citations


Journal ArticleDOI
TL;DR: Disposable cartridges containing 1 g of Florisil are investigated for cleanup of extracts obtained from various environmental matrices in the presence of interferents such as corn oil, diesel hydrocarbons, organochlorine pesticides, and chlorinated phenols.
Abstract: Disposable cartridges containing 1 g of Florisil are investigated for cleanup of extracts obtained from various environmental matrices. Elution patterns and recoveries are determined for 22 chlorinated hydrocarbons and 16 phthalate esters in the presence of interferents such as corn oil, diesel hydrocarbons, organochlorine pesticides, and chlorinated phenols. Hexane, hexane/diethyl ether (1:1), hexane/acetone (9:1), and various combinations of hexane/methylene chloride are used as eluants.

28 citations


Journal ArticleDOI
TL;DR: In this article, solid-liquid equilibrium data for green coffee oil and chlorogenic acid as a function of mass ratio of ground coffee to solvent and temperature were obtained using hexane and methanol as solvents.

24 citations


Patent
18 Aug 1989
TL;DR: In this paper, a 2-(trimethylsilylmethyl)methyl)pyrazine expressed by formula II is reacted with 2-(tert.-butyldimethylsiloxy)benzaldehyde in a polar organic solvent such as tetrahydrofuran in the presence of an alkyl lithium such as n-BuLi dissolved in a hydrocarbon solvent, at a temperature from -78°C to ambient temperature to provide the compound expressed by I.
Abstract: NEW MATERIAL:2-[2-(2-Hydroxyphenyl)vinyl]pyrazine expressed by formula I. USE: The compound expressed by formula I is stable at ambient temperature and has good crystallinity, large second high frequency-generating (SHG) activity and excellent transparency, having λmax at 348nm of short wave region, useful as non-linear optical material and also as fluorescent brightener, larger dye, etc. PREPARATION: 2-(Trimethylsilylmethyl)pyrazine expressed by formula II is reacted with 2-(tert.-butyldimethylsiloxy)benzaldehyde expressed by formula III in a polar organic solvent such as tetrahydrofuran in the presence of an alkyl lithium such as n-BuLi dissolved in a hydrocarbon solvent such as n- hexane at a temperature from -78°C to ambient temperature to provide the compound expressed by formula I. COPYRIGHT: (C)1991,JPO&Japio

19 citations


Journal ArticleDOI
TL;DR: In this article, the reactions of n-hexane over Pt-black and Pt/SiO 2 (EUROPT-1) were studied as a function of hydrogen and nhexane pressure, between 543 and 633 K.

Journal ArticleDOI
TL;DR: In this paper, the partitioning behavior of a polydisperse nonyl phenol polyethoxylate of an average ethylene oxide (EO) chain length of 7.3 units (N7.3) between water and hexane has been studied as a function of temperature and total surfactant concentration.

Journal ArticleDOI
TL;DR: In this article, the authors presented solubility data for ethane in n-hexane at temperatures from 311 to 394 K (100 to 250{sup 0}F) at pressures to 5.4 MPa (780 psia).
Abstract: Solubility data are presented for ethane in n-hexane at temperatures from 311 to 394 K (100 to 250{sup 0}F) at pressures to 5.4 MPa (780 psia). These data are in significant disagreement with earlier measurements. The new data can be described with average deviations of less than 0.001 mole fraction by the Soave-Redlich-Kwong or Peng-Robinson equations when two interaction parameters per isotherm are used in the equation.

Journal ArticleDOI
TL;DR: In this paper, the mass transfer of decanoic acid from hexane to 0.1 N NaOH is studied, and a mechanism is proposed to explain the observed emulsification, the interfacial turbulence and the long time effects.



Patent
22 Dec 1989
TL;DR: Azeotrope-like compositions comprising 1, 1,1,2-trichloro-1, 2,2, 2-trifluoroethane, methanol, nitromethane and hexane are used in a variety of vapor degreasing applications and as solvents in industrial cleaning applications as discussed by the authors.
Abstract: Azeotrope-like compositions comprising 1,1,2-trichloro-1,2,2-trifluoroethane, methanol, nitromethane, 1,2-dichloroethylene, acetone and hexane. These mixtures are useful in a variety of vapor degreasing applications and as solvents in a variety of industrial cleaning applications including defluxing of printed circuit boards.

Journal ArticleDOI
TL;DR: In this paper, a system for quantitative concentration of volatile organic trace compounds present in organic solvents is described, where solvent evaporation is carried out inside a glass capillary tube by the action of a carrier gas, and large volumes can be reduced by repeated sample injection and cyclic flow reversal.
Abstract: A system for quantitative concentration of volatile organic trace compounds present in organic solvents is described. Evaporation of the solvent is carried out inside a glass capillary tube by the action of a carrier gas, and large volumes can be reduced by a repeated sample injection and a cyclic flow reversal. Best recovery is obtained when a barrier of pure solvent is maintained ahead of the sample during concentration. Four rotary valves are employed for sample and solvent injection and direction of the gas flow. In principle, indefinite sample volumes can be handled, the limit being set by system contaminants. The process was evaluated both off-line and on-line to a gas chromatograph. Concentration of compounds like methylcyclopentane, hexane, and cyclohexane present in pentane in the low nanogram range and subsequent on-line transfer to a gas chromatograph could be performed with a quantitative recovery. The technique was applied to analysis of trace volatiles in drinking water. Detection limits were estimated to be approximately 0.02 ng/L for normal hydrocarbons (FID detection) when concentration of a pentane extract from a one litre water sample was carried out.

Journal ArticleDOI
TL;DR: In this paper, successive dilution dilatometric measurements of the excess volumes are described for {di- n -propyl ether + (n -hexane or n -octane, n -decane, or n-dodecane, and n -hexadecane) at 298.15 K. Analyses of the results in terms of the Flory theory of mixtures are discussed.

Journal ArticleDOI
TL;DR: The excess molar volumes V m E and excess refractive indices n D E of { cis -9-octadecenoic (oleic) acid + n -hexane or cyclohexane, or benzene or trichloroethene or tetrachloroeethene} have been determined as a function of mole fraction at atmospheric pressure and 298.15 K as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the solubilities of hex-1-ene, hexane and cyclohexane have been measured in liquid nitrogen at a temperature of 77.4 K by the filtration method.
Abstract: The solubilities of hex-1-ene, hexane and cyclohexane have been measured in liquid nitrogen at a temperature of 77.4 K by the filtration method. The solubilities of the C6 hydrocarbons in LN2 at 77.4 K vary from 0.5 × 10–8 mole fraction for cyclohexane, to 0.7 × 10–8 mole fraction for hexane and 0.16 × 10–6 mole fraction for hex-1-ene. The results are compared with the solubilities calculated on the basis of the Scatchard–Hildebrand equation of regular solution theory. Correlation between the solubilities of alkanes, alkenes and cyclic hydrocarbons in liquid nitrogen, and some properties of solutes {normal boiling point (Tb), critical point (Tc), heat of vaporization at normal boiling point (ΔHb), the mean of the heat of vaporization and the enthalpy of melting [(ΔHb+ΔHm)/2] and Lennard–Jones force constant (Iµ/kB} are presented.

Journal ArticleDOI
TL;DR: In this paper, groundnut flour was re-extracted with absolute ethanol, 95% isopropanol, hexane:ethanol and hexane-isopropol azeotropes for different time intervals.
Abstract: Hexane extracted groundnut flour was re-extracted with absolute ethanol, 95% isopropanol, hexane:ethanol and hexane:isopropanol azeotropes for different time intervals. Sensory evaluation studies indicated that 6 h extraction with ethanol or isopropanol and 24 h extraction with hexane; ethanol azeotrope removed nearly 80–90% of nutty flavor. Some significant changes were observed in water absorption capacity, emulsification capacity and foaming properties of secondary solvent extracted meals. No significant changes were observed in fat absorption capacity, protein solubility and amino acid composition of secondary extracted samples. Gel electrophoresis did not reveal any marked changes in the protein composition of the reextracted meals.

Journal ArticleDOI
TL;DR: A lignite humic acid was found to retain a variety of hydrophobic compounds which could be removed by repeated extraction with hexane and chloroform and analyzed by capillary GC and GC-MS as discussed by the authors.

Journal ArticleDOI
TL;DR: Les donnees d'equilibre sont mesurees a 10, 25 and 50°C, les resultats sont correles aux modeles NRTL et UNIQUAC.
Abstract: Les donnees d'equilibre sont mesurees a 10, 25 et 50°C, les resultats sont correles aux modeles NRTL et UNIQUAC

Journal ArticleDOI
Isamu Nagata1
TL;DR: In this article, the (liquid + liquid) equilibria of (acetonitrile + 2-butanol + cyclohexane or n-heptane) at 298.15 K have been measured.

Journal ArticleDOI
TL;DR: In this paper, the excess volume data on mixing for binary mixtures of trichloroethylene with hexane, heptane, cyclohexane, methylcyclohexanes, toluene, bromobenzenes, chlorobenzene and nitro-benzene have been determined at 303.15 K.

Journal ArticleDOI
TL;DR: In this article, a continuous dilution dilatometer was used to measure the excess molar volumes of an n-alkanol (C 1 to C 4 ) or an n -alkane (C 6 to C 8 ) + 1,2-dichloroethane.

Journal ArticleDOI
TL;DR: In this paper, the donnees d'equilibre de the NRTL, UNIQUAC, and UNIFAC systemes were forecasted by l'aide de trois modeles.
Abstract: Des previsions sur les donnees d'equilibre de ce systeme sont faites a l'aide de trois modeles: NRTL, UNIQUAC et UNIFAC

Journal ArticleDOI
TL;DR: In this article, pulse-gradient NMR has been used to determine self-diffusion coefficients for acetone, acetonitrile, benzene, hexane, methanol, and trimethylchlorosilane on aerosil.
Abstract: Pulse-gradient NMR has been used to determine self-diffusion coefficients for acetone, acetonitrile, benzene, hexane, methanol., and trimethylchlorosilane on aerosil. A comparison is made with the corresponding values for silica gel.

Journal ArticleDOI
TL;DR: In this article, a support is precipitated by reacting a hexane solution of the Mg dialkyl complex with SiCl 4 and then activated by treatment with TiCl4 and diisobutylphthalate in chlorobenzene.
Abstract: New, highly active supported propene polymerization catalysts are prepared by activating supports derived from Mg dialkyl complexes with sterically hindered aromatic esters, such as ethyl 2,6-dimethylbenzoate (6a), ethyl 2,4-6-trimethylbenzoate (7), or isopropyl benzoate (2b). The support is precipitated by reacting a hexane solution of the Mg dialkyl complex with SiCl4 and then activated by treatment with TiCl4 and diisobutylphthalate in chlorobenzene. Optimized catalysts of this type prepared from Mg dialkyl complex with 7 realize yields of 16–17 kg polypropylene/g catalyst in 2 h hexane slurry polymerizations at 70°C, 10,2 atm, with less than 1% boiling hexane extractables and 0,41–0,43 g/ml polymer powder bulk density. The cocatalyst-external modifier package used consists of Al(C2H5)3-dimethoxydiphenylsilane. The polymer produced is characterized by a narrow particle size distribution, which renders the title catalysts suitable for use in both slurry and solventless propene polymerization processes.