Cyclohexyl extraction

High Peroxide Process. An alternative to maximizing selectivity to KA in the cyclohexane oxidation step is a process which seeks to maximize cyclohexyUiydroperoxide, also called P or CHHP. This peroxide is one of the first intermediates produced in the oxidation of cyclohexane. It is produced when a cyclohexyl radical reacts with an oxygen molecule (78) to form the cyclohexyUiydroperoxy radical. This radical can extract a hydrogen atom from a cyclohexane molecule, to produce CHHP and another cyclohexyl radical, which extends the free-radical reaction chain. 

Several N-substituted pyrroHdinones eg, ethyl, hydroxyethyl and cyclohexyl, are used primarily in specialized solvent appHcations where their particular physical properties are advantageous. For example, mixtures of l-cyclohexyl-2-pyrroHdinone and water exhibit two phases at temperatures above 50°C below that temperature they are miscible in aH proportions. This phenomenon can be used to facHitate some extractive separations. Mixtures of 1-alkyl-pyrroHdinones that are derived from coconut and taHow amines can be used at lower cost in certain appHcations where they may be used instead of the pure l-dodecyl-2-pyrroHdinone and l-octadecyl-2-pyrroHdinone. 

N-cyclohexyl-1-chlorophthalimlde (250 g) was dissolved in glacial acetic acid (2.5 8),concentrated hydrochloric acid (555 ml) and tin (27B g) were added and the suspension was heated on a steam bath for 16 hours. The cooled solution was filtered and concentrated to dryness in vacuo to give a white solid. This solid was dissolved in water and the precipitated oil extracted with chloroform. The chloroform solution was dried and concentrated in vacuo to give a solid which, after recrystal I izat ion, yielded 5-chloro-2-cyclohexylisoindolin-1-one (43%), MP 140°Cto 142°C. 

The hexane solvent was removed from a solution of DIB AL (22 mmol, 1 Min hexane) at reduced pressure and at ambient temperature, and ether (10 ml) was introduced. l-Cyclohexyl-2-trimethylsilylethyne (20 mmol) was added at such a rate as to maintain ambient temperature within the reaction, and. after 15 min, the reaction flask was placed in a preheated (40 °C) bath for I h. The resulting clear solution was transferred by means of a double-ended syringe to a vigorously stirred cold solution of HC1 (50 ml, 10%). The flask was rinsed with ether (20 ml), and the mixture was stirred until the resulting phases were almost clear. The layers were separated, and the aqueous layer was extracted with ether (40 ml). The combined organic extracts were washed successively with dilute HC1 (20%), saturated sodium hydrogen carbonate solution and brine, and dried. 

Applications Identification of polymer additives by TLC-IR is labour intensive and comprises extraction, concentration of extracts, component separation by TLC on silica, drying, removal of spots, preparation of KBr pellets and IR analysis. The method was illustrated with natural rubber formulations, where N-cyclohexyl-2-benzothiazyl sulfenamide, IPPD and 6PPD antioxidants, and a naphthenic plasticiser were readily quantified [765]. An overview of polymer/additive type compounds analysed by transfer TLC-FTIR is given in Table 7.80. 

OTC, TC, CTC and its isomers in muscle and kidney Extraction with glycine-HCl buffer, cleanup with isolute cyclohexyl cartridge DL = 10 ng/g (muscle) 20 ng/g (kidney) Rec = 56-74% [39]... 

C. (Z)-[2-(Fluoromethylene)cyclohexyl]benzene (3). To a solution of (fluorovinyl)stannane 2 (26.0 g, 0.054 mol) in dry THF (150 mL) is added 65 mL of 1 M sodium methoxide in methanol (prepared by the addition of 1.50 g (0.065 g-atom) of sodium to 65 mL of methanol). The solution is refluxed for 18 hr under nitrogen (Note 14), cooled to ambient temperature and concentrated on a rotary evaporator. The residue is partitioned between water (200 mL) and hexane (200 mL). The aqueous layer is separated and extracted with hexane (100 mL). The combined organic layers are dried (magnesium sulfate) and concentrated on a rotary evaporator to give a colorless oil (30 g). Kugelrohr distillation gives 10.0-10.2 g (97-100%) of fluoro olefin 3 (bp 85-90°C, 0.4 mm) as a colorless oil (Note 15). 

Cleanup by solid-phase extraction has also been widely employed since it is a simple, fairly inexpensive, and easy-to-perform procedure for purification of the crude extract. The use of disposable solid-phase extraction columns is currently part of most, if not all, modern analytical methods for the determination of anthelminthics in biological matrices at residue levels. Both normal-phase columns based on silica (333-335, 340, 367, 372), alumina (346, 373-375), or aminopropyl (339, 365, 370) materials, and reversed-phase columns based on Ci8 (319, 323, 324, 328, 344, 346, 347, 349-351, 357-359, 364, 367) and cyclohexyl (329, 332, 360) sorbents have been described in analytical applications. 

Dimethyl 2-methylenepentanedioate. Methyl acrylate (30.0 g, 349 mmol) (distilled immediately before use) and dry pyridine (30 ml, CAUTION) containing tris(cyclohexyl)phosphine-carbon disulphide complex (2.0 g, 6 mmol) (1) are refluxed under nitrogen for 16 hours. The deep red solution is cooled and the pyridine removed under reduced pressure. The residue is taken up in ether (400 ml) and the solution washed with aqueous 1 m hydrochloric acid (3 x 40 ml). The combined aqueous layers are extracted with ether (2 x 50 ml) and the combined organic layers washed with 1 m hydrochloric acid (30 ml), saturated brine (40 ml) and saturated aqueous sodium hydrogen carbonate (2 x 30 ml), dried over sodium sulphate and evaporated. Distillation of the oil gives dimethyl 2-methylenepentanedioate (23.8 g, 79%) as a liquid, b.p. 66-68 °C/1 mmHg i.r. (thin film) 1738, 1715, 1635cm-1. 

Atrazine and metabolites Cyclohexyl solid-phase extraction cartridge used to separate atrazine from soil extract High-performance liquid chromatography with photodiode array detection [389-391]... 

To a solution 2-ethoxy-l-[[2 -(N-triphenylmethyltetrazol-5-yl)biphenyl-4-yl]-methyl]benzimidazole-7-carboxylic acid (0.5 g) in DMF (5 ml) were added potassium carbonate (0.12 g) and cyclohexyl 1-iodoethyl carbonate (0.26 g). The mixture was stirred at room temperature for 1 hour. To the mixture was added water and the mixture was extracted with ethyl acetate. The organic layer was washed with water and dried. After removal of the solvent, the... 

In a 100 ml flask fitted with a mechanical stirrer, a vertical condensor protected by a calcium chloride stopper, a dropping-funnel and a source of nitrogen were introduced 30 ml of hexamethylenephosphotriamide and 2.3 g (0.1 mol) of finely cut sodium wire. A mixture of 12.3 g (0.1 mol) of (3-thienyl)-acetonitrile and 16.3 g (0.1 mol) of cyclohexyl bromide was then quickly added at a temperature of 20 C. The reaction mixture was then maintained under nitrogen atmosphere and stirred for 12 hours at room temperature. The excess of sodium was destroyed by adding 5 ml of ethanol and the organic solution was slowly poured into 100 ml of a 1 N iced solution of hydrochloric acid. The solution was extracted twice with 100 ml ether. The ethereal phases were collected, washed with water, dried and concentrated under reduced pressure. The crude product was then purified by... 

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