Filter paper, hardened

Fermentation, 22, 53 Ferric nitrate, 23, 20 Fieser s solution, 21, 110 Filter fabric, Pyrex glass, 22, 33, 65 Vinyon, 22, 33, 67 Filter paper, hardened, 22, 45 Fischer indole synthesis, 22, 98 Flash distillation, 21, 85 Flask, modified Claisen, 22, 11 Fluorescence of 9-aminoacridine hydrochloride, 22, 7 Formaldehyde, 20, 60 Formalin, 22, 66 Formic acid, 20, 66, 102 23, 43 Formic acid, chloro-, benzyl ester, 23, 13... 

Filter paper, hardened, 22, 45 Shark skin, 25, 97 Fischer indole synthesis, 22, 98 Flash distillation, 21, 85 Flask, modified Claisen, 22,11 Fluorescence of 9-aminoacridine hydrochloride, 22, 7... 

Method 1. From ammonium chloroplatinate. Place 3 0 g. of ammonium chloroplatinate and 30 g. of A.R. sodium nitrate (1) in Pyrex beaker or porcelain casserole and heat gently at first until the rapid evolution of gas slackens, and then more strongly until a temperature of about 300° is reached. This operation occupies about 15 minutes, and there is no spattering. Maintain the fluid mass at 500-530° for 30 minutes, and allow the mixture to cool. Treat the sohd mass with 50 ml. of water. The brown precipitate of platinum oxide (PtOj.HjO) settles to the bottom. Wash it once or twice by decantation, filter througha hardened filter paper on a Gooch crucible, and wash on the filter until practically free from nitrates. Stop the washing process immediately the precipitate tends to become colloidal (2) traces of sodium nitrate do not affect the efficiency of the catalyst. Dry the oxide in a desiccator, and weigh out portions of the dried material as required. 

For the hydrolysis, 36 g. (O.ll mole) of the residue is transferred to a 1-1. round-bottomed flask equipped with a reflux condenser, and 210 ml. of concentrated hydrochloric acid in 190 ml. of water is added. The mixture is refluxed gently at first, then vigorously (Note 6), until hydrolysis is essentially complete (about 20 hours). Then 180 ml. of W ater and 4 g. of Norite A are added and the mixture is stirred and boiled for 3 minutes, after which it is rapidly filtered with suction through two layers of hardened filter paper in a Buchner funnel (Note 7). The filtrate, upon cooling to 20° or below, deposits 18 g. (72%) of lightly colored 2,5-dihydroxy- -benzenediacetic acid (Note 8). A snow-... 

Deliver from a pipette 10 c.c. of the oil into a glass dish (preferably a round-bottom one) of 50 c.c. capacity, which is imbedded in finely cracked ice. Add 10 c.c. of concentrated arsenic acid (containing about 85 per cent, arsenic acid), and stir until precipitation is complete. When the mixture ceases to congeal further, allow to stand ten minutes in the ice. At this point if the mixture forms a hard mass, indicating an oil rich in cineol, 5 c.c. of purified petroleum ether should be added, and the mass mixed well. Transfer immediately to a hardened filter paper by means of a pliable horn spatula, spread evenly over the surface of the paper, and lay a second hardened filter paper over the top. Outside of the hardened filters place several thicknesses of absorbent or filter paper, and transfer the whole to an ordinary letter-press, bringing to bear all the pressure... 

The hardness test sometimes is performed on the mud as well as the mud filtrate. The mud hardness indicates the amount of calcium suspended in the mud as well as the calcium in solution. This test usually is made on gypsum-treated muds to indicate the amount of excess CaSO present in suspension. To perform the hardness test on mud, a small sample of mud is first diluted to 50 times its original volume with distilled water so that any undissolved calcium or magnesium compounds can go into solution. The mixture then is filtered through hardened filter paper to obtain a clear filtrate. The total hardness of this filtrate then is obtained using the same procedure used for the filtrate from the low-temperature low-pressure API filter press apparatus. 

Method 2 from potassium bromide and sulphuric acid). Potassium bromide (240 g.) is dissolved in water (400 ml.) in a litre flask, and the latter is cooled in ice or in a bath of cold water. Concentrated sulphuric acid (180 ml.) is then slowly added. Care must be taken that the tem-peratiue does not rise above 75° otherwise a little bromine may be formed. The solution is cooled to room temperatiure and the potassium bisulphate, which has separated, is removed by filtration through a hardened filter paper in a Buchner funnel or through a sintered glass funnel. The filtrate is distilled from a litre distilling flask, and the fraction b.p. 124 127° is collected this contains traces of sulphate. Pme constant boiling point hydrobromic acid is obtained by redistillation from a little barium bromide. Tlie yield is about 285 g. or 85 per cent, of the theoretical. 

The procedure as used for solid explosives is also applied for liquid explosives. The only difference is that the mass of liquid explosive is -0.007 g. The liquid mass is absorbed on a disc of desiccated filter paper which is placed in between the hardened steel cylinders. This is described [48a] in detail in MIL-STD-650. 

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