Distillation from solids

B. 4-Phenyl-5-anilino-l,2,3-triazole. Six grams (0.025 mole) of 1,4-diphenyl-5-amino-l,2,3-triazole is dissolved in 20 g. of dry pyridine (distilled from solid sodium hydroxide) and heated under reflux for 24 hours (Note 6). The reaction mixture (Note 7) is poured into 11. of ice water. The product separates as a slightly yellowish milky oil which is converted to white needle-like crystals by stirring the mixture and scratching the beaker with a glass rod. The product is collected by suction filtration, washed with water, suction-dried, and recrystallized from aqueous ethanol (Note 8). The yield is 5.5-5.6 g. (92-93%) of fine white needle-like crystals, m.p. 167-169° (Note 9), soluble in hot water and ether, but difficultly soluble in benzene. 

Photodimerisation of cyclopent-2-enone. cis,tra.ns,cis-3,3,8-Tetramethoxy-tricyclo[5.3.0.02 6]decane and c s,. ra.ns,c s-tricyclo[5.3.0,02 6]decane-3,10-dione. Place a solution of 49.9 g (0.61 mol) of cyclopent-2-enone in 800 ml of methanol (distilled from solid potassium hydroxide) in a photochemical reactor vessel of 1-litre capacity equipped with a 100-W medium pressure mercury arc lamp surrounded by a Pyrex cooling jacket (Section 2.17.5, p. Ill), flush the magnetically stirred solution with nitrogen for 10 minutes and then irradiate under nitrogen overnight. Filter the white crystalline solid which separates and continue irradiating until no further crystalline material separates from the methanol solution. About 21.5 g of material is obtained after approximately 40 hours irradiation. Crystallisation from methanol gives cis,trans,cis-3,3,8,8-tetramethoxytricyclo[5.3.0.02,6]decane as white plates, m.p. 173-174 °C. The yield is 19.3 g (30%). 

One gram (0.87 mmole) of Fe-(a//-c s-TpivPP)Br and 0.35 g (0.7 mmole) of [Cr(acac)2]27 (acac = 2,4-pentanedionato) are heated in 35 mL of boiling tetrahydrofuran containing 1 mL (0.97 g, 11.8 mmole) of JV-methylimidazole (distilled from solid potassium hydroxide under vacuum) for 5 minutes. The resulting red-orange solution is filtered hot and allowed to cool to ambient temperature while 100 mL of heptane is slowly added. The crystals are filtered, washed with heptane, and dried in a stream of nitrogen. Yield 0.8-0.85 g (76-80%). The complex may be recrystallized from tetrahydrofuran-heptane-TV-methylimidazole. Anal. Calcd. for C72H76Ni204Fe C, 70.2 H, 6.35 N, 13.6 Fe, 4.55. Found C, 70.0 H, 6.60 N, 13.7 Fe, 4.30. 

A solution of 36 g. (0.30 mole) of m-xylidine in a solution of 60 g. of concentrated sulfuric acid in 450 ml. of water is diazotized at a temperature below 5° by the addition of a solution of 21 g. (0.30 mole) of sodium nitrite in 60 ml. of water. The resulting solution of the diazonium salt is filtered, and the filtrate is added to a solution of 50 g. (0.30 mole) of potassium iodide in 60 ml. of water. After standing 1 hour at room temperature, the mixture is warmed until evolution of nitrogen ceases, and sufficient solid sodium bisulfite is added to remove the free iodine. The separated oil is removed by extraction with ether, and the ethereal solution is distilled after being washed with 10% aqueous sodium hydroxide and dried with calcium chloride. After removal of the ether by distillation, the residual oil is distilled from solid potassium hydroxide to give 33 g. (47%) of pure iodo compound, b.p. 231-235°. 

For extraction with anhydrous ethylenediamine (EDA) H+-exchanged soil was dried in vacuo at 75°C over phosphorus pentoxide and then thoroughly mixed with EDA dried by distillation from solid sodium hydroxide. Extraction was repeated twice. 

Methanol. Purify by distillation from solid NaOH in a quartz still. Store in a polyethylene bottle. 

Powdered chromium(III) fluoride-water (1/3.5) [Alfa Products], 43.0 g (0.250 mole), is added to 52.5 g (0.875 mole) of previously dried 1,2-ethanediamine contained in a 500-mL polyethylene beaker. The 1,2-ethanediamine is dried by distillation from solid sodium hydroxide pellets. The fraction that boils from 116-118 is collected. 

Drying refers to the removal of water from a substance through a whole range of processes, including distillation, evaporation, and even physical separations such as with centrifuges. Here, consideration is restricted to the removal of moisture from solids and liquids into a gas stream (usually air) by heat, namely, thermal drying. Some of the types of equipment for removal of water also can be used for removal of organic liquids from solids. 

The term distillation is applied to vaporisation and subsequent condensation according to (i) it should also be applied to (ii) since it is really the liquid which is converted into vapour and is first formed by condensation. Strictly speaking, the term sublimation should be applied to changes according to (iii). However, in practice, a substance when heated may first melt and then boil, but on cooling it may pass directly from the vapour to the solid the process is then also called sublimation. Indeed the mode of vaporisation, whether directly from solid to vapour or through the intermediate formation of a liquid, is of secondary importance it is the direct conversion of vapour to solid which is really the outstanding feature of sublimation in the laboratory. 

The chief disadvantage of the simple vacuum distillation set up shown in Fig. 11,19, 1 is that, if more than one fraction is to be collected, the whole process must be stopped in order to change the receiver B. It is of value, however, for the distillation of solids of low melting point the distillate can easily be removed from the receiver by melting and pouring out. For routine work, involving the collection of several fractious under reduced pressure, the most convenient receiver is the so-called Perkin triangle the complete apparatus for vacuum distillation is depicted in F g. 11,20, 1. The Claisen fla.sk A is fitted to a. short water... 

It is marketed as a 35-40 per cent, solution in water (formalin). The rpactions of formaldehyde are partly typical of aldehydes and partly peculiar to itself. By evaporating an aqueous solution paraformaldehyde or paraform (CHjO), an amorphous white solid is produced it is insoluble in most solvents. When formaldehyde is distilled from a 60 per cent, solution containing 2 per cent, of sulphuric acid, it pol5unerises to a crystalline trimeride, trioxane, which can be extracted with methylene chloride this is crystalline (m.p. 62°, b.p. 115°), readily soluble in water, alcohol and ether, and devoid of aldehydic properties ... 

If the residue is dark and contains some solid matter, it is advisable to add a little anhydrous ether, and to filter the ethereal extract into the 100 ml. distilling flask the ether is removed flrst by distillation from a water bath using the apparatus of Fig. II, 13, I or Fig. II, 13, 4. 

Amino-5-methylthiazole. Suspend 76 g. of thiourea in 200 ml. of water in a 500 ml. three-necked flask equipped as in the preceding pre paration. Stir and add 92 -5 g. (80 ml.) of monochloroacetone (1) over a period of 30 minutes. The thiourea dissolves as the reaction proceeds and the temperature rises. Reflux the yellow solution for 2 hours. To the cold solution immersed in an ice bath add, with stirring, 200 g. of solid sodium hydroxide. Transfer to a separatory funnel, add a little ice water, separate the upper oil layer and extract the aqueous layer with three 100 ml. portions of ether. Dry the combined oil and ether extracts with anhydrous magnesium sulphate, remove the ether by distillation from a steam bath, and distil the residual oil under diminished pressure. Collect the 2-amino-5-methylthiazole at 130-133°/18 mm. it solidifies on coohng in ice to a solid, m.p. 44-45°. The yield is 84 g. 

Place 35 ml. of a M solution of aluminium tsopropoxide or 7 g. of solid aluminium tsopropoxide, 450 ml. of dry isopropyl alcohol and 21 g. of purified benzaldehyde (Section IV,115) in a 1 litre round-bottomed flask. Fit a short reflux condenser (no water in the cooling jacket) or better a Hahn condenser (2) (containing a 1 cm. layer of ethyl alcohol in the iimer tube) to the flask and arrange for slow distillation from a water bath at the rate of 3-6 drops per minute. Continue the heating until a negative test for acetone is obtained after 5 minutes of total reflux (6-9 hours) if the volume of the mixture falls below 200 ml. during the reduction, add more isopropyl alcohol. Remove the reflux or Hahn condenser and distil off (Fig. II, 13, 3) most of the isopropyl alcohol under atmospheric pressure from a suitable oil bath. Hydrolyse the... 

Step 2. Distillation from alkaline solution. Treat the solution Bi) remaining in the distilling flask after the volatile acidic and neutral compounds have been removed with 10-20 per cent, sodium hydroxide solution until distinctly alkaline. If a solid separates, filter it off and identify it. Distil the alkaline solution until no more volatile bases pass... 

Acidify the aqueous solution (60-76 ml.)= prepared from (a) 6-10 g. of the solid mixture, ( >) from 6-10 g. of the liquid residue (fJ) after distillation from a boiling water bath, or (c) from sufHcient of original aqueous solution to contain 6-10 g. of solute) with 20% E fSOf and distil. 

Ethers that are solids (e.g. phenyl ethers) can be steam distilled from an alkaline solution which will hold back any phenolic impurity. After the distillate is made alkaline with sodium carbonate, the insoluble ether is collected either by extraction (e.g. with chloroform, diethyl ether or toluene) or by filtration. It is then crystallised from alcohols, alcohol/petroleum ether, petroleum ether, toluene or mixtures of these solvents, sublimed in a vacuum and recrystallised if necessary. 

V-[2-Hydroxyethyl]ethylenediamine [2-(2-aminoethylamino)ethanol] [111-41-1] M 104.1, b 91.2°/5mm, 238-240°/752mm, n 1.485, d 1.030, pK 3.75, pK 9.15. Distilled twice through a Vigreux column. Redistilled from solid NaOH, then from CaH2. Alternatively, it can be converted to the dihydrochloride and recrystallised from water. It is then dried, mixed with excess of solid NaOH and the free base distilled from the mixture. It is finally redistilled from CaH2. [Drinkard, Bauer and Bailar 5 Am Chem Soc 82 2992 7960.]... 

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