Extraction cyclohexane

A solution of quinoline 1-oxide (0.29 g, 2 mmol) in cyclohexane (1 L) was dehydrated by azeotropic distillation in the reaction vessel. The solution was purged with dry N2 and irradiated with a Hanau high-pressure Hg lamp. The resulting solution was evaporated and the residue was extracted with a little cyclohexane. The insoluble part contained carbostyril (3). The cyclohexane extract was evaporated and the residue purified by short-path distillation at 50°C/0.1 Torr yield 0.174g (60%) moisture-sensitive oil. 

CYCLOHEXANE EXTRACTION. A 5-6g portion of the product was cut into small pieces and stirred in 250 ml cyclohexane at room temperature for 60 hr. The insoluble fraction was separated by filtering the solution through cheesecloth. The cyclohexane-soluble fraction was recovered by distilling the solvent in vacuo and the polymer was dried in vacuo at 40 C for 24 hr. 

A wide variety of methodologies have been employed for the analysis of antioxidants in polymers and some standard methods are available. For high-density polyethylene ASTM method D5524 (ASTM International) — Determination of phenolic antioxidants in high-density polyethylene, describes a method whereby the sample is ground to a small particle size and then extracted by refluxing with cyclohexane. The cyclohexane extract is then examined by reverse-phase HPLC with UV detection. 

Cyclohexane extractable fractions coke oven emissions, 100.0-150.0 1... 

Figure 1.4 Comparison of UV spectrum of cyclohexane extract of sulphidized pyrite after flotation with that of cyclohexane solution of sulphur (Heyes and Trahar, 1984)...

Exposure limits No individual standards have been set. As a constituent in coal tar pitch volatiles, the following exposure limits have been established (mg/m ) NIOSH REL TWA 0.1 (cyclohexane-extractable fraction), IDLH 80 OSHA PEL TWA 0.2 (benzene-soluble fraction) ACGIH TLV TWA0.2 (benzene solubles). 

The hot cyclohexane layer is carefully decanted, and the aluminum bromide layer is extracted with five 200-ml. portions of hot cyclohexane. Ether (400 ml.) is added to the cooled cyclohexane extracts (Note 11), and the combined solvent fractions are washed with two 100-ml. portions of water and dried over anhydrous magnesium sulfate. Evaporation of the solvent leaves a semi-solid residue that is partially dissolved in about 100 ml. of pentane. The undissolved white solid, diamantane, is collected by suction filtration. Additional diamantane is obtained by concentrating the pentane solution to a small volume and collecting the solid that precipitates. The total amount of diamantane obtained, after drying, is 60-62 g. (60-62%), m.p. 240-241° (closed tube) (Note 12). This product is sufficiently pure for most purposes, but it may be purified further by recrystallization from pentane to give white crystals, m.p. 244.0-245.4°. 

For PAH analysis the extraction with methylene chloride may successfully be substituted by cyclohexane extraction allowing high recoveries by one single extraction. 

Polyaromatic hydrocarbons Silver membrane filler, cyclohexane extraction Dimethysilated Chromosorb-9, 175-275°C Split flame ionisation and ultraviolet detection Combination of GLC and ultraviolet spectroscopy [641]... 

The composition of essential oil extracted using SC-C02 has been compared with that of steam-distilled oil by GC-MS (Gopalan et al., 2000b). Out of the 21 components identified, ar-turmerone and turmerone constituted about 60% of the total oil. Analysis of the cyclohexane extract of turmeric by GC-MS coupled with Pseudo Sadtler retention indices reveals a series of saturated and unsaturated fatty acids, along with sesquiterpenes. The fatty acids reported are tetradecanoic... 

The data in Table HIlikewise show a major difference between solvent extraction and distillation. Cyclohexane soluble material, CyS, had a wide spread in molecular weight as did HVL-P itself. Cyclohexane dissolved all of the Light and Middle fractions, and about 50% of the Heavy fraction and Resid in HVL-P. Thus, cyclohexane extraction is not as effective as distillation... 

Ferric Chloride on Attapulgus Clay. Ferric chloride hexahydrate (40 g), a 10% solution in methanol, was contacted with Attapulgus clay (252 g) for 8 hr. The ferric chloride-Attapulgus clay was filtered, washed several times with cyclohexane, extracted with cyclohexane for 24 hr in a Soxhlet extractor to remove nonadsorbed metallic salt, and dried at room temperature. The material contained 0.7-2.0 wt % of iron. 

Adipic acid can also be obtained from cyclohexane extracted from petroleum, or manufactured by catalytic reduction of benzene. The cyclohexane is oxidized with air in the presence of copper or cobalt, which act as catalysts, to give a mixture of cyclohexanol and cyclohexanone, both of... 

Coal tar pitch volatiles B[a]P cyclohexane extractable fraction... 

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