Precipitates, apparatus for removing liquid from

Praseodymium, separation of mixtures with lanthanum from monazite, as magnesium nitrate double salt, 2 56, 67 Praseodymium (III) nitrate, analysis of anhydrous, 5 41 Praseodymium (III) oxide, for synthesis of nitrate, 5 39w. Precipitates, apparatus for removing liquid from, 8 16 Purpureochromic chloride, 2 196 6 138... 

Fio. 6, Apparatus for effecting the removal of liquid from a precipitate. 

Equip a 3 litre three-necked flask with a thermometer, a mercury-sealed mechanical stirrer and a double-surface reflux condenser. It is important that all the apparatus be thoroughly dry. Place 212 g. of trimethylene dibromide (Section 111,35) and 160 g. of ethyl malonate (Section 111,153) (dried over anhydrous calcium sulphate) in the flask. By means of a separatory funnel, supported in a retort ring and fitted into the top of the condenser with a grooved cork, add with stirring a solution of 46 g. of sodium in 800 ml. of super dry ethyl alcohol (Section 11,47,5) (I) at such a rate that the temperature of the reaction mixture is maintained at 60-65° (50-60 minutes). When the addition is complete, allow the mixture to stand until the temperature falls to 50-55°, and then heat on a water bath until a few drops of the liquid when added to water are no longer alkaline to phenolphthalein (about 2 hours). Add sufficient water to dissolve the precipitate of sodium bromide, and remove the alcohol by distillation from a water bath. Arrange the flask for steam distillation (Fig. this merely involves... 

Samples were taken from the precipitated bottom phase, the solvent phase, and the C02 vapour phase. The sampling procedure for the bottom phase depended on whether the precipitate was a liquid (triglyceride oil), solid (lecithin) or a mixture of both components. Samples of liquid bottom phase were withdrawn from valves V3 and V16 positioned at the base of the view cell, with valve VI shut. Valves V5, V6 and V2 were opened to ensure constant pressure inside the view cell during sampling. Samples of solid lecithin were recovered by first removing the solvent phase under pressure as above, followed by depressurization, and then solvent washing of the apparatus. Lecithin was retained on a filter placed above valve V3. For mixtures of lecithin and Soya oil, the two sampling procedures were combined. The Soya oil was first removed under pressure, followed by the solvent phase. The apparatus was then depressurized and solvent washed. Samples of the solvent phase at pressure were also taken via valve V4 and collection vessel CV3, to measure the C02 content, and the concentration of solute still in solution. 

---