Ethers fractionation

Petroleum ether fractions free from aromatic hydrocarbons are marketed, as are also n-hexane and n-heptane from petroleum. 

Di-n-hexyl ether. Use 50 g. (61 ml.) of n-hexyl alcohol (b.p. 156-157°) and 6 g. (3-5 ml.) of concentrated sulphuric acid, and heat until the temperature rises to 180°. Pour the reaction mixture into water, separate the upper layer, wash it twice with 5 per cent, sodium hydroxide solution, then with water, and dry over anhydrous potassium carbonate. Distil from a 50 ml. Claisen flask, and collect the fractions of b.p. (i) 160-221° (17 g.), and (u) 221-223° (17 g.). Reflux fraction (i) with 4 g. of sodium and distil from the excess of sodium 9 - 5 g. of fairly prure n-hexyl ether, fraction (iii), are thus obtained. Combine fractions (ii) and (iii) and distil from a little sodium collect the pure n-hexyl ether (19 g.) at 221 - 5-223°. 

Bead Processes. These processes have generally replaced the above techniques. The styrene is polymerised by bead (suspension) polymerisation techniques. The blowing agent, typically 6% of low boiling petroleum ether fraction such as n-pentane, may be incorporated before polymerisation or used to impregnate the bead under heat and pressure in a post-polymerisation operation. 

The mixture is taken up with water and the base is extracted from the toluene with dilute hydrochloric acid. The hydrochloric solution is rendered alkaline with caustic soda, the base is separated with ether, dried, and after distillation of the ether fractionated in vacuo, BP at 0.05 mm Hg, 150° to 153°C. The basic ether is then dissolved in dry ether, and ether saturated with dry hydrogen chloride is added dropwise with stirring. An excess of hydrogen chloride must be avoided as it may produce decomposition to the corresponding diphenyl ethylene. The ether-moist hydrochloride is preferably dried at once in vacuo and subsequently reprecipitated from acetone-ether and then again dried in vacuo over phosphorus pentoxide. Hydrochloride, MP 12B°C. 

The ethyl acetate solution is then washed with water, dried and evaporated. To remove any selenium still present, the residue is dissolved in 200 cc of methanol and mixed with 100 g of iron powder and 2 g of active carbon. The mixture is heated for 30 minutes with stirring under reflux, then filtered with suction, washed with methanol and the solution evaporated in vacuo. The residue is then chromatographed on 900 g of aluminum oxide. The residues of the evaporated benzene and ether fractions are treated with active carbon in methanol or acetone, evaporated again, and the residue recrystallized from a mixture of acetone and ether. There are obtained 17.5 g of pure 1-dehydro-17a-methyl-testosterone which melts at 163° to 164°C. 

Soxhlet extraction of the dry gum (250 g) serially with hexanes, ether, and methanol resulted in an activity rich ether fraction (600 mg, dried in vacuo) that was partitioned between CCI4 and 50% aqueous MeOH. The dried aqueous layer (300 mg) was applied directly to droplet countercurrent chromatography (DCC), CgHg/MeOH/CHC /H ... 

Creaser C, Welch J, Bishop K. 1983. Letters to the editor. -Hcxane in petroleum ether fractions. Ann Occup Hyg 27(2) 229-230. 

Surface water samples often contain surfactants and their metabolites. After Cis-SPE combined with selective elution [7,9,10] the metabolites, PEG and PPG, were observed in the ether fraction (PPG) or in the combined methanol-water and methanol (PEG) fractions, respectively. They could be ionised in the form of their [M + NH4]+ ions applying ESI-FIA-MS(-I-) in combination with ammonium acetate for ionisation support. ESI-LC-MS(-I-) resulted in an excellent separation of both metabolites, as presented in the total ion current (TIC) trace in Fig. 2.9.6(7) together with selected mass traces of PEG (m/z 300, 344 and 388) and PPG (m/z 442, 500, 558) (Am/z 44 and 58) in Fig. 2.9.6(l)-(6) [36],... 

Procedure Dissolve accurately 22.5 mg of /ram-clomiphene citrate and 52.5 mg of cis-clomiphene citrate (approx. 1 2.3) into 10 ml of DW in a clean 50 ml separating funnel. Add to it 1 ml solution of sodium hydroxide (5% w/v in DW). In the alkaline medium the base is liberated which is extracted successively with 3 portions of solvent ether (10 ml each). The combined ethereal layer is washed with two portions of DW (10 ml each). The resulting ethereal fraction is dried over anhydrous sodium sulphate, filter, evaporate to diyness carefully over an electric water-bath and dissolve the residue in 1 ml of CS2. Now, record the absorption curve in a 0.2 mm cell over the range 12.50 to 14.00 pm. Calculate the absorbance for the peaks at 13.16 and 13.51 pm respectively by employing the base-line method (see section 3. l. B in this chapter) between the minima at 12.66 and 13.89 pm. 

Without purification, the mixture of acetates is placed in a 250-mL round-bottomed flask and 150 mL of a 10% potassium hydroxide solution in aqueous methanol is introduced at room temperature. After 24 hr of stirriqg, the brown mixture is poured into a separatory funnel, diluted with 200 mL of water, and extracted with four 150-mL portions of ether. The combined ethereal fractions are dried over anhydrous magnesium sulfate, filtered, and concentrated to give a mixture of alcohols (Note 6) as a light yellow oil. 

The results of TLC indicated that concavum produced at least three and possibly as many as five separate toxins (Table V). The three relatively distinct toxic components were designated PC-1, PC-3, and PC-5. Results from TLC did not clearly distinguish PC-2 or PC-4 from PC-5. However, mouse bloassay of these fractions (from preparative TLC) revealed that PC-4 was a fast-acting toxin in contrast to the slow-acting PC-2 and PC-5. Of course, the variation in results of the mouse bioassays could have been a consequence of different amounts and levels of purity of the respective fractions. Regardless, preliminary results from TLC and bioassay suggest that PC-2 may be the same as PC-5, the former being a water soluble carryover in the initial ether fraction. 

Petroleum ether extract of the seed, administered subcutaneously to pregnant rats at a dose of 0.6 mL/animal, was active . Antispasmodic activity. Petroleum ether fraction chromatographed and fraction eluted with chloroform, at a concentration of 0.50 mg/mL, was active on the guinea pigileum vs histamine-induced contrac-tions . Tertiary alkaloid fraction of the dried seeds produced weak activity on the dog trachea vs acetylcholine (ACh)- and KCl-induced contractions, and active on the guinea pig ileum. A concentration of 25 (Xg/mL was active on the rat uterus vs ACh-and oxytocin-induced contractions, results significant at p < 0.02 level . Methanol extract of the dried seed, at a concentration of 0.1 mg/mL, was active on the guinea pig ileum vs histamine-induced contractions . 

Cardiotonic activity. Petroleum ether fraction chromatographed and fraction eluted with chloroform, administered by perfusion at a concentration of 0.20 mg/mL, was inactive on the guinea pig heart . 

Hypotensive activity. Essential oil, administered intravenously to dogs at a dose of 3 p,L/kg, was active. The ethanol (70%) extract, administered intravenously to dogs at a dose of 75 mg/kg, was active. There was a dip followed by rise in blood pressure° . Ethanol (80%) extract of the aerial parts, at a dose of 10 mg/kg, was not blocked by atropine. The extract did not inhibit pressor response of norepinephrine either . Ethanol (95%) extract of the seed, administered intravenously to dogs at a dose of 10 mg/kg, produced a transient effect that was blocked by atropine ". Petroleum ether fraction chromatographed and fraction eluted with chloroform, administered intravenously to rabbits at a dose of 0.80 mg/kg, was inactive. Methanol extract, administered intravenously to dogs and rabbits at a... 

Extraction of soil with hexane acetone (1 1), centrifugation, separation of hexane from acetone/water layer. Extraction of acetone/water phase with chlorofornrdiethyl ether (1 1), solvent exchanged to methanol. Hexane layer contained diazinon, chloroform/diethyl ether fraction contained 2-isopropyl-4-methyl-6-hydroxy-pyrimidine. 

Furby (12) has developed a method for evaluating stocks in the lubricating oil range that results in a breakdown of components into asphaltenes, resins, wax, and dewaxed oil and provides a yield-viscosity index relationship for the dewaxed oil. The author has found such analyses very useful and inexpensive for evaluating a large number of potential lubricating oil stocks. Furby s method utilizes petroleum ether to precipitate asphaltenes, a fuller s earth-petroleum ether fractionation to isolate resins, methyl ethyl ketone-benzene dewaxing on the deasphalted-deresinified material to separate wax, and an adsorption fractionation to provide cuts from which the yield-viscosity index relationship for dewaxed, solvent-refined oil is obtained. 

The petroleum ether fraction used was Skellysolve B (boiling range 60-70°). 

Note Ethyl acetate is a solvent impurity of ether. 900 mL of solvent/700 mL of resin was successively Soxhlet extracted for 24 h with CH3OH, CH3C=N, and ether. No compounds were identified in the ether fractions. A sample was injected directly into the GC-MS. Identifications are tentative no retention time data have yet been correlated. Identifications were completed by MS only. 

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