Showing papers on "Hexane published in 1979"

On the pattern of hydrogenolysis of hexane isomers over four Group VIIIB metals

Abstract: The hydrogenolysis patterns of five hexane isomers have been compared over Rh, Pd, Ir and Pt. The selectivity of rupture of various C−C bond types is different for various metals. The “fingerprint-like” patterns are, as a rule, similar to those reported in the literature, their correlation with the position of the metal in the periodic system is pointed out.

Thermodynamic Study on the Adsorption of Dioctadecyl Ether at Hexane/Water Interface

Abstract: The adsorption of dioctadecyl ether was studied at hexane/water interface, as functions of temperature, pressure, and mole fraction of dioctadecyl ether in hexane. The phase transition between expanded and condensed films was observed with decreasing temperature and increasing pressure and concentration. The thermodynamic quantities associated with the adsorption such as entropy, volume, and energy change were evaluated and comparison was made with the adsorbed films of 1-octadecanol at the same interface in which phase transition takes place. It is found that the dioctadecyl ether shows small negative discontinuous changes of the thermodynamic quantities with the transition from the expanded to the condensed films.

Deoiling of aqueous solutions of sodium lauryl sulfate

Abstract: Free oil, often an objectionable impurity in synthetic organic detergents, such as sodium lauryl sulfate, is removed from aqueous solutions by extraction thereof with hexane in the presence of lower alkanol, with the proportion of the alkanol present being in a relatively narrow range with respect to the sodium lauryl sulfate, in which range it helps to promote efficient extraction of the free oil by the hexane without solubilizing the hexane in the aqueous medium to such an extent as to result in an extracted detergent containing an unacceptably high proportion of hexane. Separation of the free oil from the aqueous detergent solution is effected in an extractor, to which the hexane is added, in mixture with a minor proportion of lower alkanol, normally isopropanol, and extraction of the free oil takes place after a preliminary mixing of isopropanol with detergent acid or neutralized base in a neutralization vessel and/or in a mixer upstream of the extractor. In a preferred embodiment of the invention the hexane extractant feed to the extractor is that resulting from distillation separation from the free oil of the hexane with some isopropanol. Also, extracted product is evaporated and the evaporator overhead, including isopropanol, hexane and water, is fed to the mixer. The evaporator product is steam stripped, very preferably in a novel stripper described herein, and the stripper overhead, including isopropanol and water, is conveniently fed to a neutralization vessel in which detergent acid, comprising the product of sulfation of lauryl alcohol with sulfur trioxide (and containing objectionable free oil), is neutralized with aqueous sodium hydroxide. Preferably the deoiling process is a continuous one, with only free oil being removed from the extractor feed, and the hexane and isopropanol are continuously recycled.

Separation of organotin compounds by using the difference in partition behaviour between hexane and methanolic buffer solution. Part 1. Determination of butyltin compounds in textiles by graphite furnace atomic-absorption spectrophotometry

Abstract: A method for determining tributyltin compounds (TBTs) and dibutyltin compounds (DBTs) in textiles has been studied by graphite furnace atomic-absorption spectrophotometry. They are successfully extracted from textiles with methanol containing 0.05% of hydrogen chloride. Their partition between hexane and a methanolic buffer solution (pH 8.5) was studied by varying the methanol concentration of the aqueous buffer phase. Only TBTs can be extracted with hexane from a methanolic buffer solution consisting of 40 ml of methanol and 30 ml of buffer solution. TBTs are absorbed on an alumina column and eluted with a small volume of dichloromethane. DBTs remaining in the aqueous phase are extracted with dichloromethane as a complex with 4-(2-pyridylazo)resorcinol. After evaporation of the dichloromethane, the residue is heated with concentrated nitric acid and its tin concentration is determined by atomic-absorption spectrophotometry.

Cis -Unsaturated fatty acid products by hydrogenation with chromium hexacarbonyl

Abstract: The use of Cr(CO)6 was investigated to convert polyunsaturated fats intocis unsaturated products. With methyl sorbate, the same order of selectivity for the formation ofcis-3-hexenoate was demonstrated for Cr(CO)6 as for the arene-Cr(CO)3 complexes. With conjugated fatty esters, the stereoselectivity of Cr(CO)6 toward thetrans, trans diene system was particularly high in acetone. However, this solvent was not suitable at elevated temperatures required to hydrogenatecis, trans- andcis, cis-conjugated dienes (175 C) and nonconjugated soybean oil (200 C). Reaction parameters were analyzed statistically to optimize hydrogenation of methyl sorbate and soybean oil. To achieve acceptable oxidative stability, it is necessary to reduce the linolenate constituent of soybean oil below 1–3%. When this is done commercially with conventional heterogenous catalysts, the hydrogenated products contain more than 15%trans unsaturation. By hydrogenating soybean oil with Cr(CO)6 (200 C, 500 psi H2, 1% catalyst in hexane solution), the product contains less than 3% each of linolenate andtrans unsaturation. Recycling of Cr(CO)6 catalyst by sublimation was carried through three hydrogenations of soybean oil, but, about 10% of the chromium was lost in each cycle by decomposition. The hydrogenation mechanism of Cr(CO)6 is compared with that of arene-Cr(CO)3 complexes.

Positronium formation in nonpolar solvents. A comparative study of the influence of chlorinated ethanes, ethenes and cyclohexanes on the yield of o-Ps

Abstract: Inhibition of positronium formation caused by different chlorocyclohexanes, chloroethanes and chloroethenes used as additives in cyclohexane, 2,2,4-trimethylpentane, benzene and n -hexane has been investigated by means of positron lifetime measurements. Chlorocyclohexanes and chloroethanes cause increased inhibition with increasing chlorine substitution. Comparisons with earlier results of chlorobenzenes show that the behaviour of the actual additives is quite different from that of the chlorobenzenes. The results are discussed in terms of the “hot Ps-model” and the “spur-model”.

Novel vitamin d3 derivative and its preparation

Abstract: NEW MATERIAL:A compound of formula I. EXAMPLE: 24,24-Difluoro-1α,25-dihydroxyvitamin D 3 . USE: Useful medicines having a great biological activity like vitamin D. PROCESS: A provitamin D 3 derivative of formula II (R 1 , R 2 and R 3 are H or OH-protecting groups) is irradiated with ultraviolet light in a low-boiling solvent, e.g. hexane, at about room temperature, in the atmosphere of an inert gas, e.g. argon, to give a previtamin D 3 derivative of formula III, which is isomerized thermally to form a vitamin D 3 derivative of formula IV. The OH-protecting groups are eliminated from the resulting compound if necessary, in an inert solvent, e.g. hexane, in the atmosphere of an inert gas, e.g. argon. The novel compound of formula II can be obtained from a compound of formula V (X 1 and X 2 are H's or single bonds C-C). COPYRIGHT: (C)1980,JPO&Japio

Removal of Raw Peanut Flavor and Odor in Peanut Flour Processed by Direct Solvent Extraction1

Abstract: Peanut slices can be directly extracted with hexane yielding more soluble protein and better color than pre-press solvent extraction; however, flavor and odor are characterized as raw and “green beany”. The utilization of secondary extraction with hexane: ethanol azeotrope, hexane: methanol azeotrope and absolute ethanol subsequent to hexane extraction significantly improved flavor and odor characteristics of peanut flour. Hexane: propanol azeotrope did not significantly improve sensory evaluations. Hexane: ethanol azeotrope did not reduce soluble protein, yielding an NSI value of 95%. Hexane: methanol azeotrope and absolute ethanol slightly reduced NSI to 88% and 92% respectively. Color of peanut flour was not affected by secondary solvent extraction. Direct extraction of peanut slices with hexane, followed by hexane: ethanol azeotrope extraction, resulted in flour with good flavor and odor characteristics and with lighter color and more soluble protein than peanut flour produced by commercial p...

Hydroxyl anion chemical ionization screening of liquid fuel

Abstract: The use of OH/sup -/ as a reagent ion for chemical ionization screening of the aromatic components in liquid fuels is discussed. The hydroxyl anions were generated by the reactions of O/sup -/, from N/sub 2/O, with hexane, which also served as the solvent for the fuel samples. The resulting mass spectra were characterized by the absence of measurable signals from aliphatic components. The method requires no prior fractionation or separation, as well as a 2 to 3 minute turn-around time between successive analyses. Some preliminary data pertinent to determinations of actual molecular weight distributions by this technique are also presented. 4 figures, 1 table.

Solvent Extraction Equilibria of Acids. VII. The Co-extraction of Water with Strong Mineral Acids by Trioctylphosphine Oxide

Abstract: The extraction of water from a 1 mol dm−3 sodium perchlorate solution with trioctylphosphine oxide (TOPO) in four organic solvents and the co-extraction of water with hydrochloric, hydrobromic, hydroiodic, perchloric, nitric, and thiocyanic acids from 1 mol dm−3 of the acid solution by TOPO in hexane have been studied at 25 °C. The extraction constants of water in the absence of any of the acids, K′H2O=[TOPO·H2O]org[TOPO]org−1, were determined to be 100.40, 100.00, 10−0.12, and 10−0.36 in benzene, hexane, carbon tetrachloride, and chloroform respectively. A discrepancy from the 1: 1 molar ratio of TOPO and water in the extract was observed in the higher-TOPO-concentration region in the hexane system. The co-extraction of water with the acids disolvated by TOPO was greater in the order of HCl\simeqHBr>HI>HClO4, and it was much poorer with the monosolvated acids, nitric and thiocyanic acid. The equilibria for these co-extractions of water with the acids are complicated.

Processes for the preparation of 3-azabicyclo(3.1.0)hexane derivatives

Abstract: 2-Cyano-3-azabicyclo[3.1.0]hexane may be prepared by reacting 3-azabicyclo[3.1.0]hex-2-ene or the trimer thereof with an alkali metal bisulphite to form its bisulphite adduct, and treating said adduct with an alkali metal cyanide.