Methylene chloride reflux extraction

To perform a dialytic extraction, the apparatus is assembled and preextracted for 48 hours using pyridine and methylene chloride outside and inside the membrane, respectively. The coal ftvlOO g) is then slurried in a 2-3 fold excess of pyridine (ACS reagent grade) and placed in the sample compartment, where it is constantly stirred. The methylene chloride reflux is begun at this point, and the extract collects in the receiver. When the buildup of pyridine in the receiver results in stoppage of the reflux cycle, the contents of the receiver are collected, and it is refilled with clean methylene chloride. The overflow from the sample compartment was evaporated under a flow of dry nitrogen, redissolved in pyridine, and replaced in the sample compartment daily. The dialytic extraction is slower than the soxhlet procedure, and the yield is substantially less. For example, the yield of a four day dialytic extraction of Powhatan Coal was 6%, while a two day pyridine soxhlet on the same coal yields 12-15% extract. 

The ability of several methods to extract polycyclic aromatic hydrocarbons (PAHs) and other petroleum hydrocarbons from marine sediments was examined. Comparisons of soxh-let and methylene chloride reflux methods gave extraction efficiencies that showed no statistical difference in the return of PAHs however, the return when using ball-mill tumbling was significantly lower. The relative content of individual parent PAH compounds, parent compound distributions (PCDs), and alkyl homologue distributions (AHDs) of PAHs was calculated using capillary column GC-MS. The similarities of the distributions showed that any of the three methods could have been used to calculate these distributions. An examination of several extraction methods commonly used for the extraction of petroleum hydrocarbon material from sediment samples showed differences in results that depended on the extraction method employed. In addition, the methods varied in their ability to extract resolved versus unresolved material and to return aliphatic and aromatic hydrocarbon compounds. 

Figure 5. Recovery [log (ppm dry weight)] of nonalkylated PAH compounds for methylene chloride reflux, soxhlet, and ball-mill tumbler extraction methods...

Figure 6. Comparison of PAH PCDs for replicate extractions by methylene chloride reflux, soxhlet, ana ball-mill tumbler methods...

To a solution of 6.78 g of 6a-fluoro-9a-bromo-11 (3,17a,21-trihydroxy-16a-methyl-1,4-preg-nadiene-3,20-dione-21 -acetate in 175 ml of acetone was added 6.78 g of potassium acetate and the resulting suspension was heated under reflux for a period of 17 hours. The mixture was then concentrated to approximately 60 ml volume at reduced pressure on the steam bath, diluted with water and extracted with methylene chloride. The methylene chloride extracts were combined, washed with water, dried over anhydrous sodium sulfate and evaporated. 

The above crude bromohydrin was mixed with 2.5 grams of potassium acetate and 60 cc of acetone and refluxed for 6 hours, at the end of which the acetone was distilled, water was added to the residue and the product was extracted with methylene chloride. The extract was washed with water, dried over anhydrous sodium sulfate and the solvent was evaporated. Recrystallization of the residue from methanol furnished 800 mg of the 16,21-diacetate of 6o-fluoro-9(3,11(3-oxido-A -pregnene-16o,l7a,2l-triol-3,20-dione with MP 120° to 124°C by chromatography of the mother liquors on silica gel there was obtained 180 milligrams more of the same compound with MP 117° to 119°C. The analytical sample was obtained by recrystallization from methanol it showed MP 125° to 127°C. 

Isopropyl-4(or 5-nitroimidazole) (31 g = 0.2 mol), dioxane (70 g) and dimethylsulfate (28 g = 0.22 mol) were heated on a steam bath under reflux for 45 minutes. The solvent was removed in vacuo on a steam bath, the residue dissolved in 20 ml of water and the product precipitated by the gradual addition of 80 g of 25% sodium hydroxide solution at 0°C. A small additional amount was obtained by extraction of the mother liquor with methylene chloride. The product melted at 60°C. 

In the final production preparation, a mixture of ethyl methyl(3-benzoylphenyl)cyano-acetate (48 g), concentrated sulfuric acid (125 cc) and water (125 cc) is heated under reflux under nitrogen for 4 hours, and water (180 cc) is then added. The reaction mixture is extracted with diethyl ether (300 cc) and the ethereal solution is extracted with N sodium hydroxide (300 cc). The alkaline solution is treated with decolorizing charcoal (2 g) and then acidified with concentrated hydrochloric acid (40 cc). An oil separates out, which is extracted with methylene chloride (450 cc), washed with water (100 cc) and dried over anhydrous sodium sulfate. The product is concentrated to dryness under reduced pressure (20 mm Hg) to give a brown oil (33.8 g). 

Methyl ethyl (7-methoxy-10-methyl-3-phenthiazinyl)malonate (62.2 grams) followed by methyl iodide (45.7 grams) is added to a solution of sodium (4.45 grams) in anhydrous ethanol (500 cc). The reaction mixture is heated under reflux for 1 hour at 45°C, then for 6 hours at 55°C, and finally concentrated to dryness under reduced pressure (20 mm Hg). The residue is taken up in methylene chloride (300 cc) and water (250 cc), filtered in the presence of a filtration adjuvant, washed with methylene chloride (150 cc) and water (150 cc), and decanted. The aqueous solution is extracted once again with methylene chloride (100 cc), and the combined organic solutions washed with water (100 cc), aqueous 0.1 N sodium hyposulfite solution (200 cc) and finally with water (200 cc). After drying over anhydrous sodium sulfate and evaporation to dryness under reduced pressure (20 mm Hg), there is obtained an oil (64.8 grams) which is dissolved in methylene chloride (100 cc) and... 

To a flame-dried, three-neck, 1-1 flask were added, in order, p-xylene (107 g, 1.0 mol), phosphorus trichloride (412 g, 3.0 mol), and anhydrous aluminum chloride (160 g, 1.2 mol). The reaction mixture was slowly heated to reflux with stirring. After 2.5 h at reflux, the reaction was allowed to cool to room temperature and the volatile components distilled at reduced pressure. The residual oil was slowly added to cold water (1 1) with stirring, and a white solid formed. The solid was removed by filtration, washed with water, and air dried. The solid was suspended in water (1 1) to which was added 50% sodium hydroxide solution (90 ml) to cause dissolution. The solution was saturated with carbon dioxide and filtered through Celite . The basic solution was washed with methylene chloride (200 ml) and acidified with concentrated hydrochloric acid (200 ml). The white solid that separated was isolated by extraction with methylene chloride (3 x 250 ml). The extracts were dried over magnesium sulfate, filtered, and evaporated under reduced pressure to give the pure 2,5-dimethylbenzenephosphinic acid (99 g, 60%) as an oil, which slowly crystallized to a solid of mp 77-79°C. 

To a stirred suspension of N-(2,6-dimethyl-4-oxopyridin-l-yl)pyridin-ium tetrafluoborate (0.58 g, 2 mmol) in dry acetonitrile (20 ml) under nitrogen was added trimethyl phosphite (0.25 g, 2 mmol), followed by finely divided sodium iodide (0.30 g, 2 mmol). After 1 h at 25°C, the solvent was removed under reduced pressure, and water (20 ml) was added. The mixture was extracted with methylene chloride (3 x 15 ml), and the extracts were dried over magnesium sulfate, filtered, and evaporated under reduced pressure. The residue was dissolved in ethyl acetate (40 ml), heated at reflux for 4 h, evaporated under reduced pressure, and eluted on an alumina column (grade 1, neutral) with chloroform to yield pure dimethyl pyridin-4-ylphosphonate (0.36 g, 96%) of melting point (mp) 139 to 140°C. 

Reduce 3,5-dimethoxybenzoic acid with lithium aluminum hydride to 3,5-dimethoxybenzyl alcohol (I), to 10.5 g (I) in 100 ml methylene chloride at 0° C add 15 g PBr3 warm to room temperature and stir for one hour. Add a little ice water and then more methylene chloride. Separate and then dry, evaporate in vacuum the methylene chloride. Add petroleum ether to precipitate about 11.5 g of the benzyl bromide (II). To 9.25 g (II), 15 g Cul, 800 ml ether at 0° C, add butyl (or other alkyl)-Li (16% in hexane), and stir for four hours at 0° C. Add saturated NH4C1 and extract with ether. Dry and evaporate in vacuum the ether (can distill 100/0.001) to get about 4.5 g olivetol dimethyl ether (HI) or analog. Distill water from a mixture of 90 ml pyridine, 100 ml concentrated HC1 until temperature is 210° C. Cool to 140 0 C and add 4.4 g (III) reflux two hours under N2. Cool and pour into water. Extract with ether and wash with NaHC03. Make pH 7 and dry, evaporate in vacuum to get 3.8 g olivetol which can be chromatographed on 200 g silica gel (elute with CHC13) or distill (130/0.001) to purify. 

If the allyl isomer is at hand, it must fixi be converted to the propenyl as follows (CJC 43,3437( 1965)tif Add equal weights of the allyl compound and KOH flakes, and absolute ethanol and heat on steam bath or reflux for twenty-four hours dry and evaporate in vacuum or add two times the volume of water and extract with ether or methylene chloride and dry, evaporate in vacuum (recrystallize-hexane). 

Amino alcohol, 1 The succinimido alcohol, 7, (1.74g) was dissolved in 60 mL of 95% ethanol and 36 mL of 20% aqueous sodium hydroxide added to the solution. The solution was the refluxed for 18 hours and cooled to ambient which resulted in the separation of two layers. The top, organic, layer was separated and evaporated to dryness to give a solid material which was refluxed with 30 mL of MTBE and 10 mL of methylene chloride for 30-40 minutes to extract the amino alcohol from the solid sodium succinate. After cooling to ambient the solid was removed by filtration through a Celite pad and the filtrate decolored by stirring with Norit. Filtration gave... 

In every analysis of propellants an extraction must be performed. The latest description of the method used by the US Armed Forces is of 1971 (Ref 5). Roweg, Soxhler or equivalent extractor must be used and as extracting solvent, diethyl ether or anhydrous methylene chloride. Proceed as follows Transfer an accurately weighed sample of propint, about 5g, to the thimble of the extractor and add prescribed solvent to the tared extraction flask. Insert the open lower part of the extractor into die neck of the extraction flask and insert thru the upper opening of the extractor die bottom opening of the reflux condenser. Assemble the apparatus on the hot plate, and adjust the temperature so that the solvent drips from die condenser at the rate of 2—3 dtops per second. Extract for a time which experience or preliminary work has shown to be adequate for the type of sample. It takes 3 to 20 hours and for Roweg extractor 2—3 times faster chan for Soxhlet. 

A. Gravimetric Procedure, a) Place an accurately weighed 2g sample of proplnt in a small paper thimble, cover with glass wool extract with methylene chloride for 3 hrs in a Soxhlet app with a 250-mm refluxing flask. Remove the methylene chloride by... 

B. and C. 2-Methyl-4H-pyran-4-one. A 1000-mL, round-bottomed flask equipped with a stir bar and a reflux condenser is charged with the crude acylated Meldrum s acid, 80 mL of butyl vinyl ether and 287 mL of toluene (or benzene) (Note 6). The reaction mixture is heated to 80°C for 7 hr (Note 7). The volatile components are removed under reduced pressure to yield 31.81 g of product (Note 8). To the residue are added 765 mL of tetrahydofuran, 191 mL of water and 2.7 g of p-toluenesulfonic acid. The mixture is heated to reflux for 18 hr, then the reaction is quenched with 10 g of solid sodium bicarbonate and allowed to stir for 15 min at 25°C (Note 9). The mixture is filtered to remove the sodium bicarbonate and the volatile components are removed under reduced pressure. The residue is dissolved in 500 mL of methylene chloride, placed in a separatory funnel and washed with 200 mL of water and 200 mL of brine solution. The aqueous layers are collected and extracted with methylene chloride (2 x 200 mL). The organic layers are combined, dried over 20 g of sodium sulfate for 1 hr, filtered into a 1000-mL, round-bottomed flask, and concentrated under reduced pressure. The resulting red oil is purified by chromatography using a 6-cm diameter glass column packed with 400 g of silica gel... 

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