Cooling Homogeneous

There are only a small number of investigations where real coexistence data were measured. This is mainly due to very long equilibrium times (usually weeks) which are necessary for obtaining thermodynamically correct data. A common method is to cool homogeneous solutions in ampullae very slowly to the desired temperature in the LLE-region and... 

DO apparent solution homogeneous mixture, crystallises on cooling homogeneous mixture... 

USAEC Report LAMS-1611(Del.), Los Alamos Scientific Laboratory, Dec. 2, 1953 A Brief Description of a One Megawatt Convection-cooled Homogeneous Reactor—LAPRE II, USAEC Report LA-1942, Los Alamos Scientific Laboratory, Apr. 13, 1955. R. P. Hammond, Los Alamos Homogeneous Reactor Program, in HRP Civilian Power Reactor Conference Held at Oak Ridge, March 21-22, 1956, USAEC Report TID-7524, Los Alamos Scientific Laboratory, March 1957. (pp. 168-176)... 

Storage 2 yr. min shelf life when stored in unopened original drums 20-25 C prolonged exposure to heat may cause physical separation into liq. and solid phase on cooling homogenize to restore to original form Cremophor RH 60 [BASF BASF AG]... 

Reduction to aminophenol. Reduce about 0 5 g. of o-nitrophenol with cone. HCl and tin as described on p. 385. After a few minutes the yellow molten o-nitrophenol disappears completely, the solution becoming homogeneous and colourless due to the formation of 0-aminophenol (which is soluble in HCl). Cool and add 30% aqueous NaOH solution note that a white precipitate is first formed and then redissolvcs in an excess of NaOH, and that the solution does not develop an orange coloration, indicating that the nitro-group has been reduced. 

For methyl alcohol, two volumes of synthetic n-hexane, b.p. 68-6-69 0° (uncorr.), and one volume of the alcohol to be tested are mixed and the homogeneous mixture is cooled in ice until the appearance of a cloudiness. A thermometer is placed in the solution, which is allowed to warm gradually to the temperature at which the second phase disappears. The... 

Cool 1 ml. of amylene in ice and add 1 ml. of cold, dilute sulphuric acid (2 acid 1 water), and shake gently until the mixture is homogeneous. Dilute with 2 ml. of water if an upper layer of the alcohol does not separate immediately, introduce a little sodium chloride into the mixture in order to decrease the solubility of the alcohol. Observe the odour. The unsaturated hydrocarbon is thus largely reconverted into the alcohol from which it may be prepared. 

Dissolve or suspend 0 - 5 g. of the acid in 5 ml. of water in a small conical flask, add a drop or two of phenolphthalein indicator, and then 4-5 per cent, sodium hydroxide solution until the acid is just neutrahsed. Add a few drops of very dilute hydrochloric acid so that the final solution is faintly acid (litmus).f Introduce 0-5 g. of p-bromophenacyl bromide (m.p. 109°) dissolved in 5 ml. of rectified (or methylated) spirit, and heat the mixture under reflux for 1 hour if the mixture is not homogeneous at the boiling point or a solid separates out, add just sufficient alcohol to produce homogeneity. [Di- and tri-basic acids require proportionately larger amounts of the reagent and longer refluxing periods.] Allow the solution to cool, filter the separated crystals at the pump, wash with a little alcohol and then with water. Recrystallise from dilute alcohol dissolve the solid in hot alcohol, add hot water until a turbidity just results, clear the latter with a few drops of alcohol, and allow to cool. Acetone may sometimes be employed for recrystallisation. 

Into a 750 ml. round-bottomed flask furnished with a reflux condenser place a solution of 34 g. (18-5 ml.) of concentrated sulphuric acid in 100 ml, of water add 33 g. of di-n-butyl cyanamide and a few fragments of porous porcelain. Reflux gently for 6 hours. Cool the resulting homogeneous solution and pour in a cold solution of 52 g. of sodium hydroxide in 95 ml. of water down the side of the flask so that most of it settles at the bottom without mixing with the solution in the flask. Connect the flask with a condenser for downward distillation and shake it to mix the two layers the free amine separates. Heat the flask when the amine with some water distils continue the distillation until no amine separates from a test portion of the distillate. Estimate the weight of water in the distillate anp add about half this amount of potassium hydroxide in the form of sticks, so that it dissolves slowly. 

Add 101 g. (55 ml.) of concentrated sulphuric acid cautiously to 75 ml. of water contained in a 1 htre beaker, and introduce 35 g. of finely-powdered wi-nitroaniline (Section IV,44). Add 100-150 g. of finely-crushed ice and stir until the m-nitroaniUne has been converted into the sulphate and a homogeneous paste results. Cool to 0-5° by immersion of the beaker in a freezing mixture, stir mechanically, and add a cold solution of 18 g. of sodium nitrite in 40 ml. of water over a period of 10 minutes until a permanent colour is immediately given to potassium iodide - starch paper do not allow the temperature to rise above 5-7° during the diazotisation. Continue the stirring for 5-10 minutes and allow to stand for 5 minutes some m-nitrophenjddiazonium sulphate may separate. Decant the supernatant Uquid from the solid as far as possible. 

In a 500 ml. flask, fitted with a reflux condenser, place 53 g. of 1-chloro-methylnaphthalene (Section IV.23), 84 g, of hexamethylenetetramine and 250 ml. of 1 1 acetic acid [CAUTION 1-Chloromethylnaphtha-lene and, to a lesser degree, a-naphthaldehyde have lachrymatory and vesicant properties adequate precautions should therefore be taken to avoid contact with these substances.] Heat the mixture under reflux for 2 hours it becomes homogeneous after about 15 minutes and then an oil commences to separate. Add 100 ml. of concentrated hydrochloric acid and reflux for a further 15 minutes this will hydrolyse any SchifiF s bases which may be formed from amine and aldehyde present and will also convert any amines into the ether-insoluble hydrochlorides. Cool, and extract the mixture with 150 ml. of ether. Wash the ether layer with three 50 ml. portions of water, then cautiously with 50 ml. of 10 per cent, sodium carbonate solution, followed by 50 ml. of water. Dry the ethereal solution with anhydrous magnesium sulphate, remove the ether by distillation on a steam bath, and distil the residue under reduced pressure. Collect the a-naphthaldehyde at 160-162718 mm. the yield is 38 g. 

Hydrolysis of benzyl cyanide to phenylacetamide. In a 1500 ml. three-necked flask, provided with a thermometer, reflux condenser and efficient mechanical stirrer, place 100 g. (98 ml.) of benzyl]cyanide and 400 ml. of concentrated hydrochloric acid. Immerse the flask in a water bath at 40°. and stir the mixture vigorously the benzyl cyanide passes into solution within 20-40 minutes and the temperature of the reaction mixture rises to about 50°, Continue the stirring for an additional 20-30 minutes after the mixture is homogeneous. Replace the warm water in the bath by tap water at 15°, replace the thermometer by a dropping funnel charged with 400 ml. of cold distilled water, and add the latter with stirring crystals commence to separate after about 50-75 ml. have been introduced. When all the water has been run in, cool the mixture externally with ice water for 30 minutes (1), and collect the crude phenylacetamide by filtration at the pump. Remove traces of phenylacetic acid by stirring the wet sohd for about 30 minutes with two 50 ml. portions of cold water dry the crystals at 50-80°. The yield of phenylacetamide, m.p. 154-155°, is 95 g. RecrystaUisation from benzene or rectified spirit raises the m.p. to 156°. 

C. The mixture was cooled to -70°C and the allene (0.22 mol) was added in 5-10 min while maintaining the temperature between -60 and -70°C. After stirring for an additional 30 min at -60°C the solution was ready for further conversions. In the raetallation with ethyllithium the salts initially present had disappeared almost completely after this period. During the lithiation with commercial butyl-lithium the reaction mixture was continuously homogeneous. The solution of the lithiated allenes should be kept below -60°C and used within a few hours. 

To a mixture of 0.40 mol of neohexene ( commercially available) and 200 ml of dry diethyl ether 0.35 mol of bromine was added with cooling between -40 and -50°C. The diethyl ether and excess of neohexene were then completely removed by evaporation in a water-pump vacuum.In the second flask was placed a solution of 90 g of commercial KO-tert.-C9H9 (see Chapter IV, Exp. 4, note 2) in 250 ml of DMSO. The dibromo compound was added in five portions during 15 min from the dropping funnel after the addition of each portion the flask was swirled gently in order to effect homogenization. Much heat was evolved and part of the tert.-butylacetylene passed over. After the addition the flask was heated for 30 min in a bath at B0-100°C. 

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