Fluted filter paper, preparation

Place 0 5 ml. of acetone, 20 ml. of 10% aqueous potassium iodide solution and 8 ml. of 10% aqueous sodium hydroxide solution in a 50 ml. conical flask, and then add 20 ml. of a freshly prepared molar solution of sodium hypochlorite. Well mix the contents of the flask, when the yellow iodoform will begin to separate almost immediately allow the mixture to stand at room temperature for 10 minutes, and then filter at the pump, wash with cold w ater, and drain thoroughly. Yield of Crude material, 1 4 g. Recrystallise the crude iodoform from methylated spirit. For this purpose, place the crude material in a 50 ml. round-bottomed flask fitted with a reflux water-condenser, add a small quantity of methylated spirit, and heat to boiling on a water-bath then add more methylated spirit cautiously down the condenser until all the iodoform has dissolved. Filter the hot solution through a fluted filter-paper directly into a small beaker or conical flask, and then cool in ice-water. The iodoform rapidly crystallises. Filter at the pump, drain thoroughly and dry. 

The benzene used in this preparation should be reasonably free from toluene therefore use a sample of benzene supplied by dealers as crystalUsable benzene, i.e.y one which crystallises readily when cooled in ice-water. It should preferably be dried over calcium chloride and, immediately before use, filtered through a fluted filter-paper. The pyridine should also preferably be dried over solid potassium hydroxide and redistilled. 

Place about o-i g. (or 0 1 ml.) of the amine in a test-tube, add o-i ml. of glacial aatic acid to dissolve the amine and then add water until the test-tube is half-full Next place about 0 3 g. of the peroxidase preparation in a very small mortar and grind up with about 15 ml. of water. Filter through a small fluted filter-paper into a test-tube. 

Benedict s solution Is prepared as follows. Dissolve 86-5 g. of crystallised sodium citrate (2Na,C,H(0, l 1H,0) and 50 g. of anhydrous sodium carbonate in about 350 ml. of water. Filter, if necessary. Add a solution of 8-65 g. of crystallised copper Sulphate in 50 ml. of water with constant stirring. Dilute to 500 ml. The resulting solution should be perfectly clear if it is not, pour it through a fluted filter paper. 

SI 1996 No. 1342 extraction Weigh 5 g prepared sample to the nearest 0.001 g, and place in a 500-ml volumetric flask. Add 450 ml water at 20-25°C and shake for 30 min on a rotary shaker at 35-40 turns per minute. Make up to the mark with water and mix. Filter through a dry fluted filter paper into a dry container. A sample of triple superphosphate should give a solution of approximately 2000 pg P mM. 

In a 250 ml. separatory funnel place 25 g. of anhydrous (er/.-butyl alcohol (b.p. 82-83°, m.p. 25°) (1) and 85 ml. of concentrated hydrochloric acid (2) and shake the mixture from time to time during 20 minutes. After each shaking, loosen the stopper to relieve any internal pressure. Allow the mixture to stand for a few minutes until the layers have separated sharply draw off and discard the lower acid layer. Wash the halide with 20 ml. of 5 per cent, sodium bicarbonate solution and then with 20 ml. of water. Dry the preparation with 5 g. of anhydrous calcium chloride or anhydrous calcium, sulphate. Decant the dried liquid through a funnel supporting a fluted filter paper or a small plug of cotton wool into a 100 ml. distilling flask, add 2-3 chips of porous porcelain, and distil. Collect the fraction boiling at 49-51°. The yield of [Pg.276]

The flask is heated by steam in a large can, and the reaction mixture is evaporated to dryness under reduced pressure (Note 6). The dry residue of ammonium chloride and isobutyramide is boiled 10 minutes with 2 1. of dry ethyl acetate, and the boiling solution is filtered quickly through a fluted filter paper on a large hot funnel. The residue on the filter is extracted in the same way with two 1-1. portions of ethyl acetate. The combined ethyl acetate extracts are cooled to 0°, and the crystalline amide which separates is removed by filtration. The filtrate is concentrated to about 300 ml. and chilled, and a second crop of amide is collected (Notes 7 and 8). The two crops of isobutyramide are combined and dried, first in an oven at 70° for 3 hours and then in a vacuum desiccator. The yield of glistening white needles melting at 127-129° is 203-215 g. (78-83%) (Note 9). This material is suitable for the preparation of isobutyronitrile. 

Reflux the crude p-nitrobenzylidene diacetate with a mixture of 70 ml of ethanol, 70 ml of water and 7 ml of concentrated sulphuric acid for 30 minutes, filter through a fluted filter paper and cool the filtrate in ice. Collect the crystals by suction filtration, wash with cold water and dry in a vacuum desiccator. The yield of p-nitrobenzaldehyde, m.p. 106 °C, is 15 g (55% overall). The spectroscopic characteristics are discussed with those of the ortho isomer, cognate preparation below. 

Preparation of Thiocyanogen Solutions. To a suspension of 30 g. of plumbous thiocyanate in 300 ml. of the acetic acid is added 5 ml. of the bromine solution. The mixture is agitated vigorously on a shaking machine until it is practically colorless, and another portion of the bromine solution is added. This procedure is continued until all the bromine solution has been added. The mixture is then rapidly filtered through a dry fluted filter paper. ... 

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