Dryness point

Selection of solvents. The choice of solvent will naturally depend in the first place upon the solubility relations of the substance. If this is already in solution, for example, as an extract, it is usually evaporated to dryness under reduced pressure and then dissolved in a suitable medium the solution must be dilute since crystallisation in the column must be avoided. The solvents generally employed possess boiling points between 40° and 85°. The most widely used medium is light petroleum (b.p. not above 80°) others are cycZohexane, carbon disulphide, benzene, chloroform, carbon tetrachloride, methylene chloride, ethyl acetate, ethyl alcohol, acetone, ether and acetic acid. 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

Cesium perchlorate [13454-84-7], CsClO, mol wt 232.35 and theoretical cesium content hi.25/q, is a crystalline powder that decomposes at 250°C Cesium fluoride [13400-13-0], CsF, mol wt 151.90, theoretical cesium content 87.49%, has a melting point of 682—703°C and a boiling point of 1253°C. Cesium fluoride is an extremely hygroscopic, colorless, crystalline soUd it has a solubUity of 3.665 kg/L of water at 18°C. Cesium fluoride is made by exactly neutrali2ing cesium hydroxide with hydrofluoric acid and evaporating the resultant solution to dryness at 400°C. Excess HE results in a bifluoride salt that does not decompose at 400°C, and carbonate in the starting material gives an alkaline product. 

Ruthenium (III) chloride (2H2O) (P-form) [14898-67-0] M 207.4 + HjO, m >500 (dec), d 3.11, pK 3.40 (for aquo Rh hydrolysis). Dissolve in H2O, filter and concentrate to crystallise in the absence of air to avoid oxidation. Evaporate the solution in a stream of HCl gas while being heated just below it boiling point until a syrup is formed and finally to dryness at 80-100 and dried in a vacuum over H2SO4. When heated at 700° in the presence of CI2 the insoluble a-form is obtained [Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Vol II 1598 1965 J Org Chem 46 3936 1981]. 

Constant dryness or constant quality lines Lines on a steam, gas, or psychro-metric chart passing through all the state points of equal dryness fraction. 

Cyano-17-(2 -tetrahydropyranyloxy)-androst-5-en-3j5-ol Acetate A solution of 10 g of 17-cyanoandrost-5-en-3j5,17-diol 3-acetate in 40 ml of 2,3-dihydropyran is treated at the boiling point with 0.2 ml of phosphorus oxychloride for 1.5 hr. The solution is then diluted with ether, washed with aqueous sodium carbonate, and then water, dried over sodium sulfate and distilled under reduced pressure. The oily residue is crystalhzed from petroleum ether to give 6.7 g of 17a-cyano-17j5-(2 -tetrahydropyranyloxy)-androst-5-en-3) -ol acetate mp 127-130° [a]o —92° (diox). The mother liquor when evaporated to dryness yields an oily residue of 7.1 g which resists crystallization attempts. Subsequent reactions (see below) indicate it to be 17jS-cyano-17a-(2 -tetrahydropyranyloxy)-androst-5-en-3jS-ol acetate. 

Chloro-1 -methyl-5-phenyl-s-trizolo[4,3-a]quinoline A stirred mixture of 6triethyl-orthoacetate (0.925 g,0.0057 mol) and xylene (100 ml) was refluxed, under nitrogen, for 2 hours 40 minutes. During this period the ethanol formed in the reaction was removed by distillation through a short,glass helix-packed column. The mixture was concentrated to dryness In vacuo and the residue was crystallized from methanol-ethyl acetate to give 1.28 g of 7-chloro-1-methyl-5-phenyl-s-triazolo[4,3-a]-quinoline (83.9% yield). The analytical sample was crystallized from methylene chloride methanol and had a melting point 252.5°-253.5°C. 

A mixture of 1.63 g of 5-hydroxy-3,4-dihydrocarbostyril, 2.5 g of epibromohydrin and 2 drops of piperidine was heated at a temperature of 95°C to 100°C for a period of 4 hours with stirring. The reaction mixture was then concentrated to dryness under reduced pressure and the residue was recrystallized from acetone to obtain 1.2 g of 5-(2,3-epoxy)propoxy-3,4-dihy-drocarbostyril as a colorless powder having a melting point of 172°C to 173°C,... 

The ether extract is evaporated to dryness to give about 500 mg of a crude product. From the ether solution there is obtained about 290 mg of yellow crystals, MP 220° to 236°C which is 17a,20,20,21-bis(methylenedioxy)-11 (3-formyloxy-2-hydroxy-methylene-6,16a-di-methyl-4,6-pregnadiene-3-one. The analytical sample is recrystallized from ethyl acetate and has a melting point of 249° to 255°C, [oIq -217°, I R 5.81 and 8.37 ji. From the mother liquor is obtained about 127 mg of 17a,20,20-21-bis(methylenedioxy)-11(3-hydroxy-2-hydroxymethylene-6,16a-dimethyl-4,6-pregnadiene-3-one. The analytical sample is recrystallized from ether and has a melting point of 200° to 204°C, [alo -197°, IR 6.05 to 6.2 and 6.4 jd. 

A mixture consisting of 8 grams of estriol, 20 grams of succinic acid anhydride and 60 ml of pyridine is heated at 90 C for 4 hours, after which the reaction mixture is poured into water. The aqueous solution is extracted with ether, the ether layer is separated, washed with diluted sulfuric acid and after that with water until neutral, then evaporated to dryness to obtain 14 grams of an amorphous substance. Melting point 82° to 86°C. This drying residue proves to consist of a mixture of estriol disuccinate and estriol monosuccinate, which are separated by repeated crystallization from a mixture of methanol and water. 

A mixture of 20 g of 1 -bromo-3,5-dimethyladamantane, 75 ml of acetonitrile, and 150 ml of concentrated sulfuric acid was allowed to react overnight at ambient room temperature. The red reaction product mixture was poured over crushed ice, and the white solid which precipitated was taken up in benzene and the benzene solution dried over sodium hydroxide pellets. The benzene solution was filtered from the drying agent and evaporated to dryness in vacuo to yield 1 B.2 g of product having a melting point of about 97°C and identified by infrared spectrum as 1-acetamido-3,5-dimethvladamantane. 

It was then cooled, washed with water, dried over sodium sulfate and evaporated to dryness. The residue was crystallized from benzene and pentane to give 138.5 g of the dicyclobutane-carbonyl derivative, melting point about 112°C (dec.). 

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