Filtration filter funnel

Add 5 ml. (5 g.) of acetophenone, 1-25 g. of finely powdered paraformaldehyde, and 3 5 g. of dry dimethylamine hydrochloride to 8 ml. of absolute ethanol, and then boil the mixture under reflux for 1-5 hours. Filter the solution (which is now almost entirely clear) through a preheated filter-funnel, and cool the filtrate in ice-water with stirring. The propiophenone hydrochloride rapidly separates as white crystals filter oflF the crystals at the pump and recrystallise from a small quantity of ethanol m.p. 155-156°. Yield, 2 5 g. 

Pads of a mixture of paper pulp and asbestos fiber are used in bacteriological filtrations. In sheet form it is employed in the laboratory for all kinds of filtration. Filter papers are made in many grades of porosity for use in porcelain and glass funnels. Industrially, paper in the form of sheets is used directly or as a precoat in filter presses. 

The simplest apparatus used for filtration is the filter funnel fitted with a filter paper. The funnel should have an angle as close to 60° as possible, and a long stem (15 cm) to promote rapid filtration. Filter papers are made in varying grades of porosity, and one appropriate to the type of material to be filtered must be chosen (see Section 3.34). 

The size of the filter paper selected for a particular operation is determined by the bulk of the precipitate, and not by the volume of the liquid to be filtered. The entire precipitate should occupy about a third of the capacity of the filter at the end of the filtration. The funnel should match the filter paper in size the folded paper should extend to within 1-2 cm of the top of the funnel, but never closer than 1 cm. 

To carry out a filtration, the funnel containing the properly fitted paper is placed in a funnel stand (or is supported vertically in some other way) and a clean beaker placed so that the stem of the funnel just touches the side this will prevent splashing. The liquid to be filtered is then poured down a glass rod into the filter, directing the liquid against the side of the filter and not into the apex the lower end of the stirring rod should be very close to, but should not quite touch, the filter paper on the side having three thicknesses of paper. The... 

Fick s law 592 Filter funnel 102 Filter papers 115 folding of, 116 incineration of, 120, 121 macerated, 450 quantitative, (T) 116 Filter pulp 450 Filtering crucibles 102 Filters, optical 661 Filtration 102, 106, 115 accelerated, 450 technique of, 116, 117 with filter papers, 116 with filtering crucibles, 117 Flame emission spectroscopy 779, 797 background correction, 795 elementary theory of, 780 D. of alkali metals by, 812... 

The glass filter funnel containing Celite was preheated using a heat gun to avoid precipitation of product in the funnel. After filtration, an additional preheated mixture of 120 mL of heptane and 30 mL of toluene was passed through the Celite using suction. A precipitate forms in the filtrate, which is redissolved by heating to reflux. 

Methoxyphenyl)-2-phenyl-lH-imidazole. A 2-L, three-necked, round-bottomed flask equipped with an addition funnel, reflux condenser, and mechanical stirrer is charged with 500 mL of tetrahydrofuran (THF) and 125 mL of water. Benzamidine hydrochloride monohydrate (50 g, 0.29 mol) (Note 1) is added, followed by the slow, portionwise addition of potassium bicarbonate (54.4 g, 0.57 mol) (Note 2). The reaction mixture is vigorously heated to reflux. A solution of 4-methoxyphenacyl bromide (65.3 g, 0.29 mol) in 325 mL of THF is then added dropwise via the addition funnel over a period of 30 min while the reaction is maintained at reflux. After completion of the addition, the mixture is heated at reflux for 18-20 hr (Note 3), then cooled in an ice bath (Note 4), and THF is removed under reduced pressure using a rotary evaporator. An additional 100 mL of water is added, and the resulting suspension is stirred at 50-60°C for 30 min. The mixture is cooled in an ice bath and the solids are collected by filtration. The filter cake is rinsed with two 100-mL portions of water and air-dried in the filter funnel for 2 hr. The crude product is transferred to a 500-mL flask and 150 mL of diisopropyl ether and 150 mL of hexanes are added. The mixture is stirred for 2 hr at room temperature, and the solids are again collected by filtration. The filter cake is dried in a vacuum oven for 48 hr (68°C/ca. 100 mm) to give 68.6 g (96%) of the desired imidazole as an off-white solid (Notes 5, 6). 

The analytical method for difiufenican is as follows. A 50-g soil sample is extracted with 100 mL of acetonitrile for 45 min with a rotary shaker at 240 rpm. The mixture is centrifuged for 10 min at 3000 rpm, the supernatant is filtered through a glass filter funnel with anhydrous sodium sulfate and the filtrate is collected. ... 

Transfer the filtrate from Section 6.1.1 or 6.1.2 to a 500-mL separatory funnel and add 150 mL of 5% aqueous sodium chloride solution. Rinse the filter flask from the extraction procedure with two 40-mL portions of dichloromethane. Add both 40-mL rinses to the separatory funnel. Partition the residue into the dichloromethane. Filter the dichloromethane extract through a 10-cm filter funnel containing ca 50 g of anhydrous sodium sulfate supported on a plug of glass wool. Collect the dichloromethane in a 500-mL round-bottom flask. Repeat the partition and filtration steps with an additional 60 mL of dichloromethane. Rinse the sodium sulfate filter cake with 20 mL of dichloromethane and combine the partition and rinse solvents. Concentrate the combined dichloromethane solvents to dryness in a rotary evaporator under reduced pressure at <40 °C. 

For milk, transfer the entire sample extract into a separatory funnel (250-mL), add an equivalent volume of dichloromethane plus a half equivalent volume of sodium chloride solution (5%, w/v). Shake the separatory funnel for 2 min and allow the phases to separate. Partially fill a glass filter funnel with anhydrous sodium sulfate (approximately 10 g) and filter the lower dichloromethane layer through the sodium sulfate, collecting the filtrate in a round-bottom flask (250-mL). Wash the sodium sulfate with dichloromethane (5 mL) and collect the washings in the same round-bottom flask. Rotary evaporate the sample to dryness under reduced pressure with a water-bath temperature of 40 °C. Dissolve the residue in 4 mL of ethyl acetate-toluene (3 1, v/v) and transfer the solution to a suitable vial ready for GPC cleanup. 

A spirit burner. .., blow-pipe, one platinum crucible, one platinum sheet and 3-4 platinum wires, a test tube stand with 10-12 test tubes, several beakers and flasks, one porcelain dish and a pair of porcelain crucibles, several glass filter funnels in various sizes, a wash-bottle, several rods and watch glasses, one agate mortar, several iron spoons, a pair of steel or brass pincers, a filtration stand made of wood and one iron tripod stand. 

Hunt [34] has described a simple method of filtering soil extracts that eliminates the need for filter-funnels and receivers. It therefore reduces the risk of contamination and speeds up the procedure. It also offers a convenient means of obtaining filtrates in the field for subsequent analysis. 

In order to remove the substance from the filter plate after filtration the funnel is inverted over a basin or watch-glass and all the material is transferred to the latter with the help of a thin glass rod- or copper wire the glass button is pushed out from its lower end. The plate is removed with forceps, but the paper not before it is dry. The material which adheres to the funnel is removed without loss by scraping with a small, obliquely cut piece of thin cardboard. 

The distillate is at once extracted with ether and the extract, after having been separated from the water, is heated on the water bath until most of the ether has distilled. The residue, which contains unchanged phenol as well as the salicylaldehyde, is now vigorously shaken in a small glass-stoppered bottle with two volumes of concentrated commercial sodium bisulphite solution. A thick paste of the bisulphite compound of the aldehyde is formed. After this paste has stood for from half an hour to one hour the bisulphite compound is separated by filtration at the pump, pressed well on the filter funnel, and washed several times, first with alcohol and finally with ether, until completely free from adherent phenol. The crystals (small plates, iridescent like mother-of-pearl) are then decomposed with dilute sulphuric acid in a small round-bottomed flask whi( h is fitted with an air condenser and gently warmed on the water bath. After the liquid thus produced has cooled, the aldehyde which separates is extracted with ether and the ethereal solution is dried with anhydrous sodium sulphate. The pure aldehyde which remains when the ether is evaporated distils at 196°. The yield amounts to 10-12 g. 

After some hours the blue-green compound of copper and acetylacetone is separated by filtration with suction, washed twice with water, transferred directly from the filter funnel to a separating funnel, and, after being covered with ether, decomposed by continuous shaking with 50 c.c. of 42V-sulphuric acid. The ethereal solution is separated and the acid layer is extracted with ether the extract is then combined with the ethereal solution, which is now dried over calcium chloride. After the ether has been removed by distillation the diketone is likewise distilled. The bulk of the material passes over at 125°-140° and, on repeating the distillation, at 135°-140°. The boiling point of the completely pure substance is 139°. Yield 15-20 g. 

Using a medium size filter funnel, add enough silica gel to the depth of about 1.5 covered with sand. Prewash the silica gel with methylene chloride (CH2CI2) under suction, discarding the filtrate. Add the reaction mixture and flush with CH2CI2. Dicyclohexylurea remains at the top of the silica gel bed. 

Any insoluble impurities are removed by filtration. This is usually carried out as hot filtration. The filter funnel and conical flask used in the filtration are heated before use. This prevents the solvent mixture from cooling prematurely and forming crystals on both the filter paper and in the stem of the funnel. 

Separation of the o- andp-Toluidines. The oil from the distillation is separated from the water, ice and salt are added, and the mixture is stirred. A whitish-yellow crystalline compound appears, which is the hydrate of the p- compound. This is filtered off through an ice cooled filter funnel, and then is well pressed to remove any oily o- compound. The o- compound is separated from the filtrate with a separation funnel. 

A 2-1. two-necked round-bottomed flask fitted with a mechanical stirrer and a reflux condenser is charged with 40.0 g. (0.22 mole) of p-cyanobenzenesulfonamide (Note 1), 600 ml. of 75% (v/v) formic acid, and 40 g. of Raney nickel alloy (Note 2). The stirred mixture is heated under reflux for 1 hour (Note 3). The mixture is filtered with suction through a Buchner funnel coated with a filter aid (Note 4), and the residue on the funnel is washed with two 160-ml. portions of 95% ethanol. The combined filtrates are evaporated under reduced pressure with a rotary evaporator (Note 5). The solid residue (Note 6) is heated in 400 ml. of boiling water and freed from a small amount of insoluble material by decantation through a plug of glass wool placed in a filter funnel. The filtrate is chilled in an ice bath and the precipitate is collected by filtration with miction, washed with a small amount of cold water and dried at 50°... 

Procedure. Weigh 20 g of air-dry soil sieved to 2 mm into a 250-ml wide-mouth high-density polyethylene screw-cap bottle. The square type bottles fit best the square box of the reciprocating shaker. Add 100 ml 1 M KCI and shake for 15 min. Transfer all the suspension to a filter funnel holding a Whatman No. 6 paper, and collect the filtrate. When leaching has ceased, add two successive 50-ml aliquots of 1 M KCI. Combine the leachates from the total addition of 200 ml (some will be retained in the soil) and mix. 

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