Glass frit filter

Small filter tube with Jena glass fritted filter plate (13 f. G 2). 

Tetrasodium tris(4,4 -dicarboxylato-2,2 -bipyridine)ruthenium(II)hydrate (3) (0.2 g) is taken in a 50-mL flask containing 20 mL of distilled water. The pH of this solution is taken to 2.5 by the addition of 0.1 M HC1 or HN03, and the mixture is allowed to stand for 24 h at 0°C. The resulting precipitate is collected on a medium-porosity sintered-glass fritted filter and washed 2-3 times with pH 2.5 water. The yield is 0.13 g (88%). 

The reflux condenser is replaced quickly by a transfer tube with a coarse glass frit filter. The transfer tube leads to a 300-ml. two-necked flask, the other neck of which is attached to the mineral oil bubbler. The apparatus is swept with nitrogen, and the apparatus is carefully turned upside down, so that the precipitate of triethylammonium iodide is filtered from the benzene solution of the product. The triethylammonium iodide can be dissolved in cold absolute ethanol, and any insoluble residue added to the crude product obtained from the benzene filtrate. The ethanol solution can be evaporated to dryness, and the triethylammonium iodide weighed to check on the extent of the reaction. 

Preparation of Oils for Analysis. The light oils were used as sampled. All were essentially free from water and particulates. The heavy oils contained some water and sand. Water was removed by using a Barrett receiver while azeotroping with toluene. The solutions of heavy oils in hot toluene subsequently were filtered through glass-fritted filter funnels with fine pore sizes (4-5.5 fi) to remove sand particles. Then the sand was washed several times with hot toluene. Toluene was removed in vacuo using a rotary film evaporator and a hot water bath. The final removal of solvent was accomplished at 4 mm of mercury pressure and at 90°C waterbath temperature. 

During the addition of bromine, NaBr 2HgO separates out. After completion of the addition of the bromine, the mixture is allowed to stand for one hour at —8°C it is then filtered from the easily filterable NaBr 2HaO (about 180 g.) through a glass frit filter, the filtrate beir collected in a suction flask cooled to —5°C. 

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