Funnel, Buchner

Pressure-equalizing dropping funnel Buchner flask (1 L)... 

Funnel, Buchner, 5 cm Gas diffusion tube Gloves, plastic Goggles, safety Hollow cathode, Hg Hot plate Paper, filter, 5 cm Pipet, delivery, 1 mL Pipet, Mohr, 1.0 mL Pump, diaphragm, like Neptune Dyna-pump... 

Aspirator, water Balance, top loading Beaker, 250 mL Cylinder, graduated, 50 mL Dryer, hair Flask, filter, 125 mL Funnel, Buchner, 5 cm Goggles, safety Hot plate... 

Cylinder, graduated, 100 mL Dish, Petrie, both top and bottom Flask, filtering, 2000 mL Funnel, 270-310 mm Funnel, Buchner, 5.5 cm Funnel, separatory, 4 liter preferred, but at least 2 L. 

This type of filtration is almost invariably performed with the aid of a Buchner flask and funnel, by means of which a rapid and almost complete separation can be obtained. The Buchner flask A (Fig. 4) consists of a simple thick-walled conical flask with a short side-arm for connection to a water-pump. Into the neck of the flask is fitted the Buchner funnel B which consists usually of a cylindrical porcelain funnel, the bed of which is pierced by a... 

When crystallisation is complete, the mixture of crystals and crude mother-liquor is filtered at the pump, again using a Buchner funnel and flask as described on p. 10, and the crystals remaining in the funnel are then pressed well down with a spatula whilst continual suction of the pump is applied, in order to drain the mother-liquor from the crystals as effectively as possible. If it has been found in the preliminary tests that the crystalline material is almost insoluble in the cold solvent, the crystals in the... 

The filtration of crystals is carried outusing a small conical Buchner funnel (C, Fig. 4, p. 10) or a funnel of similar design but having a sintered filtration plate. Alternatively an ordinary conical funnel in which is placed a circular perforated plate can be used. 

Add 5 g. of potassium hydrogen tartrate and 5 g. of antimony trioxide (each being finely powdered) to 30 ml. of water contained in a small flask, and boil the mixture under a reflux water-condenser for 15 minutes. Then filter hot, using a Buchner funnel and flask which have been preheated by the filtration of some boiling distilled water. Pour the clear filtrate into a beaker and allow to cool. Potassium antimonyl tartrate separates as colourless crystals. Filter, drain and dry. Yield, 5 g. The product can be recrystallised from hot water, but this is usually not necessary. 

Dissolve 5 g. of aniline hydrochloride in 120 ml. of hot water contained in a 200 ml. conical flask and then add 4 g. of potassium cyanate. Heat the solution on a water-bath for 30 minutes, adding about 1-2 g. of animal charcoal towards the end of the heating if a slight turbidity has developed. Now bring the solution quickly to the boil over a gauze, and filter it at the pump, using a Buchner funnel and flask which have been preheated by the filtration of some boiling distilled water. The clear... 

When the ij hours boiling is complete, preheat a Buchner funnel and flask by pouring some boiling water through the funnel with the filter-paper already in position, and then quickly filter the boiling solution. Transfer the filtrate to a beaker to cool, and then wash the insoluble residue of diphenylurea on the filter twice with hot water, and drain thoroughly. Cool the filtrate in ice-water the monophenylurea separates as colourless needles. Filter at the pump and drain well. Recrystallise the crude product from boiling water, as in the previous preparation. Yield of monophenylurea, 2 5-3 g. m.p. 147°. 

The insoluble residue of diphenylurea from the original filtration is chemically almost pure. It may be recrystallised from hot rectified spirit or ethanol, a process which will be necessary if the material contains fragments of porcelain. When using either of these solvents, however, the hot solution should be filtered at the pump using a small Buchner funnel and flask which again have been preheated by the filtration of some of the hot solvent, as the solution when cooled rapidly deposits the diphenylurea. iSym-Diphenylurea (or carbanilide) is thus obtained as fine colourless crystals, m.p. 237° yield, 1-1 5 S ... 

Filter off the glycine through a Buchner funnel, and then transfer it to a beaker, add 80 ml. of methanol and stir the mixture well. Then filter again, wash the glycine on the filter with a small quantity of ether, drain and dry. 

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