Carboneous fractions, filters

The precipitated oily base is taken up in a total of 100 parts by volume of benzene. The benzene layer, dried over potassium carbonate, is filtered and then evaporated under reduced pressure. The residue from the evaporation is distilled in a high vacuum after separating a preliminary distillate which passes over up to 228°C under a pressure of 0.92 mm Hg, the principal fraction, 2-methylmercapto-10-[2 -(N-methyl-piperidyl-2")-ethyl-1 ]-phenothiazine, which distills over at 228° to 232°C under the last-mentioned pressure, is collected. The analytically pure base has a BP of 230°C/0.02 mm Hg. 

Ice-acetone bath. The bottle is closed with a rubber stopper which is clamped or wired securely in place (Note 3) and is shaken mechanically at room temperature until the suspended malonic acid dissolves (Note 4). The bottle is chilled in an ice-salt bath and opened then the contents are poured into a separatory funnel containing 250 ml. of water, 70 g. of sodium hydroxide, and 250 g. of ice. The mixture is shaken (carefully at first), the layers are separated, and the aqueous portion is extracted with two 75-ml. portions of ether. The organic layers are combined, dried over anhydrous potassium carbonate, and filtered into a dropping funnel attached to the neck of a 125-ml. modified Claisen flask (Note 5). The flask is immersed in an oil bath at about 100°, and the excess isobutylene and ether are removed by flash distillation effected by allowing the solution to run in slowly from the dropping funnel. The dropping funnel is then removed, and the residue is distilled at reduced pressure. The fraction boiling at 112—115°/31 mm. is collected. The yield of colorless di-tert-butyl malonate is 60.0 62.0 g. (58-60%), 1.4158-1.4161,... 

Sparteine is recovered by making the aqueous phases basic with aqueous 20% sodium hydroxide (NaOH) (160 mL) (Note 14). The aqueous phase is extracted with EtgO (4 x 150 mL), and the combined organic phases are dried over potassium carbonate (K2C03), filtered, and the solvents removed under reduced pressure to afford 30.3 g (98%) of crude, recovered sparteine as a pale yellow oil (Note 15). Fractional distillation of the residual oil from calcium hydride (CaH2) (Note 5) affords 27.0 g of sparteine (88%) suitable for reuse. 

The ester is purified as follows It is washed once with 10 per cent sodium carbonate solution and twice with an equal volume of saturated sodium chloride solution it is then dried twenty-four hours over anhydrous potassium carbonate. The potassium carbonate is filtered off and the ester allowed to stand overnight with about 2 per cent of its weight of phosphorus pentoxide. The ester is then distilled through a column directly from the phosphorus pentoxide a fraction that distils over a range of two degrees or less should be taken. Lower yields of butyroin may be obtained from less carefully purified ester. 

The mass balance problem can be solved readily for organic carbon. The filtrates of each fraction filtered sequentially are missing organic matter of a size larger than the membrane cutoff. By measuring either the retentate or filtrate TOC in mg/L, the mass of TOC in each successive filtrate fraction can be determined if it is assumed that (I) the TOC of molecular size less than the membrane cutoff passes in proportion to the volume (2) the membrane behaves ideally as a molecular sieve at each cutoff and (3) the volume is known. Given these conditions, a system of equations (Table V) for either retentate or filtrate fractions can be... 

The acetone is refluxed with successive small quantities of potassium permanganate until the violet colour persists. It is then dried with anhydrous potassium carbonate or anhydrous calcium sulphate, filtered from the desiccant, and fractionated precautions are taken to exclude moisture. 

If it is desired to purify an inferior product, 1 litre of it is refiuxed for 6 hours with 85 ml. of acetic anhydride and then distilled through a fractionating column the liquid passing over at 56-57° is collected. The distillate is shaken with 20 g. of anhydrous potassium carbonate for 10 minutes, filtered and redistilled. The resulting methyl acetate has a purity of 99- 9 %. 

Ethyl acetate. Various grades of ethyl acetate are marketed. The anhydrous comjjound, b.p. 76-77°, is of 99 per cent, purity, is inexpensive, and is suitable for most purposes. The 95-98 per cent, grade usually contains some water, ethyl alcohol and acetic acid, and may be ptuified in the following manner. A mixture of 1 litre of the commercial ethyl acetate, 100 ml. of acetic anhydride and 10 drops of concentrated sulphuric acid is refluxed for 4 hours and then fractionated. The distU-late is shaken with 20-30 g. of anhydrous potassium carbonate, filtered and redistilled. The final product has a purity of about 99-7% and boils at 77°/760 mm. 

Freshly distilled ethyl formate must be used. Commercial ethyl formate may be purified as follows. Allow the ethyl formate to stand for 1 hour with 16 per cent, of its weight of anhydrous potassium carbonate with occasional shaking. Decant the ester into a dry flask containing a little fresh anhydrous potassium carbonate and allow to stand for a further hour. Filter into a di flask and distil through an efficient fractionating column, and collect the fraction, b.p. 53-54° protect the receiver from atmospheric moisture. 

Commercial diethyl carbonate may be purified by the following process. Wash 100 ml. of diethyl carbonate successively with 20 ml. of 10 per cent, sodium carbonate solution, 20 ml. of saturated calcium chloride solution, and 25 ml. of water. Allow to stand for one hour over anhydrous calcium chloride with occasional shaking, filter into a dry fiask containing 5 g. of the same desiccant, and allow to stand for a further hour. Distil and collect the fraction boiling at 125-126°. Diethyl carbonate combines with anhydrous calcium chloride slowly and prolonged contact should therefore be avoided. Anhydrous calcium sulphate may also be used. 

Pour the reaction mixture cautiously into 400 g. of crushed ice and acidify it in the cold by the addition of a solution prepared by adding 55 ml. of concentrated sulphuric acid to 150 ml. of water and then coohng to 0°. Separate the ether layer and extract the aqueous layer twice with 50 ml. portions of ether. Dry the combined ethereal solutions over 50 g. of anhydrous potassium carbonate and distil the filtered solution thror h a Widmer column (Figs. II, 17, 1 and II, 24, 4). Collect separately the fraction boihng up to 103°, and the dimethylethynyl carbinol at 103-107° Discard the high boiling point material. Dry the fraction of low boihng point with anhydrous potassium carbonate and redistil. The total 3 ield is 75 g. 

Separate the ketone layer from the water, and redistil the lattCT rmtil about one third of the material has passed over. Remove the ketone after salting out any dissolved ketone with potassium carbonate (5). Wash the combined ketone fractions four times with one third the volume of 35-40 per cent, calcium chloride solution in order to remove the alcohol. Dry over 15 g. of anhydrous calcium chloride it is best to shake in a separatory funnel with 1-2 g. of the anhydrous calcium chloride, remove the saturated solution of calcium chloride as formed, and then allow to stand over 10 g. of calcium chloride in a dry flask. Filter and distil. Collect the methyl n-butyl ketone at 126-128°. The yield is 71 g. 

The experimental details for mono-M-propylanillne are as follows. Reflux a mixture of 230 g. of aniline and 123 g. of n-propyl bromide for 8-10 hours. Allow to cool, render the mixture alkafine, and add a solution of 150 g. of zinc chloride in 150 g. of water. Cool the mixture and stir after 12 hours, filter at the pump and drain well. Extract the thick paste several times with boiling light petroleum, b.p. 60-80° (it is best to use a Soxhlet apparatus), wash the combined extracts successively with water and dilute ammonia solution, and then dry over anhydrous potassium carbonate or anhydrous magnesium sulphate. Remove the solvent on a water bath, and distil the residue from a Claisen flask with fractionating side arm (well lagged). Collect the n-propyl-aniline at 218-220° the yield is 80 g. Treat the pasty solid zincichloride with an excess of. sodium hydroxide solution and steam distil 130 g. of pure aniline are recovered. 

---