Biichner funnel

The catalyst is previously prepared in an apparatus for catalytic hydrogenation, in which are placed 0.5 g. of palladous chloride, 3.0 g. of Norite, and 20 ml. of distilled water. The bottle is swept out with hydrogen and then shaken with hydrogen for 2-3 hours at 2-3 atmospheres (40 lb.) pressure. The palladium on carbon is collected on a Biichner funnel, washed with five 50-ml. portions of distilled water, then with five 50-ml. portions of 95% ethanol, and finally twice with ether. Upon drying, about 3 g. of the catalyst is obtained. It is stored in a vacuum desiccator over solid sodium hydroxide. If the reduction of the chloro-lepidine does not proceed normally, the used catalyst should be removed by suction filtration and a fresh 3-g. portion of catalyst added. Failure of the reduction step is usually due to an inactive catalyst or to impurities in the acetic acid or chlorolepidine. The palladium catalysts, prepared as described elsewhere in this volume, are presumably also satisfactory for the reduction of 2-chlorolepidine (p. 77). 

One hundred grains (0.7S mole) of -methylacetophenonc is added to a mixture of 250 ml. (4 moles) of concentrated nitric acid (sp. gr, 1.42) and 1 1. of water in a 3-1. flask, and the mixture is refluxed in a hood for 4 hours. After the mixture has been cooled, the sticky, yellow solid is collected on a 14-cm. Biichner funnel, pressed down well, and washed with 300 ml. of cold water. 

Mikro-nutsche, /. micro suction filter, esp. micro Biichner funnel, -orgamsmen, m.pl. microorganisms. 

The precipitated potassium sulfate is filtered by passing the solution through a 12-cm. Biichner funnel. The light-yellow or yellowish green filtrate is transferred to a 5-1., one-necked, round-... 

The crude diaminotoluene (Note 12) is dissolved in eight times its weight of benzene (212 g.) at 70°, and the solution is filtered quickly through a hot Biichner funnel (Note 13) with moderate suction (Note 14). The filtrate is cooled to 25° and the mother liquor is decanted from the brown crystals. The mother liquor is concentrated to a volume of 25 cc. by distillation under atmospheric pressure, and then cooled to 25°. The mother liquor is decanted from the diaminotoluene and the entire product is dried in the air. The yield is 22.5 g. (81 per cent of the theoretical amount based on the diaminotoluene sulfate used 74 per cent based on the dinitrotoluene used) of a product which melts at 98°. 

In a 3-I. beaker are placed no g. (1.2 moles) of aniline, 150 g. (1.76 moles) of sodium bicarbonate and 1 1. of water, and the mixture is cooled to 12-15° by the addition of a small amount of ice. The beaker is then fitted with ail efficient mechanical stirrer. The blade of a large porcelain spatula should be inserted into the liquid to overcome the rotary motion and thus obtain better mixing. The stirrer is started and 254 g. (1 mole) of powdered iodine is added in 15-20 g. portions at intervals of two to three minutes so that all the iodine is introduced during the course of one-half hour. Stirring is continued for twenty to thirty minutes. By this time the reaction is complete, and the color of the free iodine in the solution has practically disappeared. The crude -iodoaniline, which separates as a dark crystalline mass, is collected on a Biichner funnel, pressed as free from water as possible, and dried in the air. The filtrate may be saved for the recovery of iodine (Note 1). 

Procedure. Place a part of a wet sample in a tared Biichner funnel. Remove the bulk of liquid by suction and the rest by air-drying followed by heating in a vacuum oven at 65° to const wt (requires 3 or more hrs, but not more than 25 hrs). Transfer from the funnel an accurately weighed portion of dried LA (ca 1.7g) to a glass vial shown on fig. 

Treated Sample Place 20 to 25 g of the starch sample in a 250-mL beaker, add 200 mL of a 7 3 methanokwater mixture, disperse the sample, and agitate mechanically for 15 min. Recover the starch by vacuum filtration in a 150-mL medium-porosity fritted-glass or Biichner funnel, and wash the wet cake with 200 mL of the methanokwater mixture. Reslurry the wet cake in the solvent, and wash it a second time in the same manner. Dry the filter cake in an air oven at a temperature below 50°, then grind the sample to 20-mesh or finer, and blend thoroughly. Determine the amount of dry substance by drying a 5-g portion in a vacuum oven, not exceeding 100 mm Hg, at 120° for 5 h. 

If a purer product is desired, the amino acid is dissolved in 16 times its weight of boiling water, and to the solution is added absolute ethyl alcohol (46 cc. per g. of acid). The solution is stirred mechanically while it is cooled in an ice-water mixture. After three hours, the snow-white crystals are collected on a Biichner funnel and are washed with 300 cc. of 95 per cent ethyl alcohol, in small portions, and dried as before. The recovery of amino acid, melting at 221° with decomposition (Note 4), is 81 per cent. 

After the boiled solution is cooled to room temperature, it is diluted to its original volume with water. The potassium tetraoxalatozirconate is precipitated by the slow addition of 300 ml. of absolute ethanol. The white, finely crystalline product is filtered on a Biichner funnel and washed with 25 ml. of ethanol. The precipitate is dissolved in... 

Biichner funnel and treated as described in Part B. The i-antipode is immediately precipitated from the filtrate by slow addition, with stirring, of 100 ml. of ice-cold ethanol. The green precipitate is collected on a 5-cm. Buchner funnel, washed with three 10-ml. portions of ice-cold ethanol or methanol, and air-dried. The yield is approximately 0.50 g. (91%). For a 0.032% aqueous solution in a 1-dm. tube, = —0.62°, and [a] = —1940°. The high optical density of even so dilute a solution makes observation of the field difficult. With the Rudolph high-precision polarime-ter, the half-shade angle control should be used at its maximum opening. 

The green diastereoisomer from Part A is washed with 20 ml. of ice-cold ethanol, air-dried, and suspended in 20 ml. of ice water. Two milliliters (0.0018 mol) of 3% hydrogen peroxide, two drops (approximately 0.0018 mol) of glacial acetic acid, and 1 g. (0.006 mol) of potassium iodide are added. The olive-colored mixture is stirred in an ice bath for 4 minutes and is then filtered through a 5-cm. Biichner funnel. If the oxidation continues to occur in the filtrate, it may be necessary to refilter the filtrate once.f The d-antipode is precipitated by the addition, with stirring, of 100 ml. of ice-cold ethanol to the filtrate. The product is collected, washed, and dried in the same manner as the f-antipode. The yield is approximately 0.27 g. (49%). 

Filter off the crystals on a Biichner funnel, wash them with a small amount of ice-cold water, then with dilute ethanol, and, finally, with a 96% ethanol solution. Write the equations of the reactions. Dry the salt in the air and weigh it. Calculate the yield in per cent. Prove that you have obtained a complex cobalt salt. 

A) Filtration on the Buchner Funnel. The Biichner funnel is used for large-scale filtrations. If the quantity of material is small (<2 g), the Hirsch funnel can be used. Properly matched Buchner funnels, filter paper, and flasks are shown in Fig. 6. The Hirsch funnel shown in the figure is an old-style porcelain type. 

Biichner funnels are normally used for filtration under reduced pressure. They may be obtained in one piece or in a form which may... 

In a 12-1. flask, equipped with a low-temperature thermometer and surrounded by an ice-salt bath, a solution of sulfurous acid is prepared by saturating 2.4 1. of water at 0-5° with sulfur dioxide from a cylinder. A brisk stream of the gas is continued (Note 2) while the cold diazonium salt solution is added in about 150-ml. portions over a 30-minute period and the temperature iS maintained at 5-10° the reaction mixture assumes a dark orange color (Note 3). The cooling bath is removed, but sulfur dioxide is passed into the mixture for an additional half hour. After the mixture has been allowed to stand for 12 hours at room temperature, 3 1. of concentrated hydrochloric acid (sp. gr. 1.18) is added the n-hydrazinobenzoic acid hydrochloride separates at once. The mixture is chilled to 0-5° and filtered through a precooled Biichner funnel the product is washed with two 50-ml. portions of ice-cold dilute (1 1) hydrochloric acid. The yield is 50-51 g. (86-88%) the salt melts at 194-195° with decomposition (Note 4) and is suitable for the next step without further purification (Note 5). 

A double filter (described above) may be used in this, but in most cases a single filter is sufficient. Since the Biichner funnels are made of porcelain, and consequently are opaque, they must be carefully cleaned immediately after using. 

Similar to the Biichner funnel in its construction and action is the so-called Nutsch filter. This consists of a shallow dish with a perforated bottom, which is fitted to the cover of a tubulated cylinder by means of a rubber ring, the joint being air-tight. This apparatus is especially adapted tothe filtration of larger quantities than can be conveniently treated in the Btichner funnel (Fig. 39). 

Phosphorus (red) [7723-14-0] M 31.0, m 590 /43atm, ignites at 200 , d4 2.34. Heat it for ISminutes in boiling distilled H2O, allow it to settle and wash it several times with boiling H2O. Transfer it to a Biichner funnel, wash it with hot H2O until the washings are neutral, then dry it at 100 and store it in a desiccator. 

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