Fractionating columns condenser

In a 12-1. three-necked, round-bottomed flask, fitted with a powerful stirrer (Note 1) and a reflux condenser, are placed 1260 g. (15 moles) of cyanoacetamide,1 1 kg. of salt (Note 2), and 5 1. of ethylene dichloride. After the mixture has been stirred rapidly for 15 minutes, 800 ml. (8.75 moles) of phosphorus oxychloride is added and the mixture is refluxed for 8 hours in an oil bath (Note 3). After the mixture has been cooled to room temperature, it is filtered and the solid is washed with 500 ml. of ethylene dichloride. The solvent is distilled from the combined filtrates in a 12-1. flask, and the residual crude nitrile is decanted into a 1-1. flask (Note 4) from any solid that may have separated. A fractionating column, condenser, and fractionating receiver are attached, and the mal-ononitrile is distilled under reduced pressure. The fraction boiling at 113-118°/25 mm. weighs 570-654 g. (57-66%) (Note 5). This material may be freed from a small amount of phosphorus oxychloride which is present by redistillation. After a fore-run of about 5 ml., the malononitrile distils smoothly at 92-94°/8 mm. 

All commercially available fractionation processes can give comparable performances. Basically, each process uses a deaerator, heat source, fractionation column, condensing system, and vacuum source. These processes may differ in the internals of the column, in the manner of evaporation and condensation, and in the piping arrangement for better heat recovery, but they can give equally good results. 

Preparation, (a) Measure 20 ml. (20 g.) of paraldehyde into a 50-ml. round-bottomed flask, add a cooled mixture of 0.5 ml. each of coned, sulfuric acid and water, attach a fractionating column, condenser, and ice-cooled receiver, and heat gently with a microburner at such a rate that acetaldehyde distils at a temperature not higher than 35°. To avoid charring of the mixture, continue only until about half of the material has been depolymerized. 

NAPHTHENIC ACID. CrHaOj. In laboratory tests, alloy 3003 was resistant to commercial naphthenic acid at ambient temperature and 82 C (180°F). Boiling naphthenic acid was very corrosive to 3003 alloy in the same test. Naphthenic acid has been transported in aluminum alloy tank cars. Aluminum alloy fractionating columns, condensers, receivers and piping have been used in the production and handling of naphthenic acid. See also Ref (Dp. 137. (7)p. 

In such a plant the gas stream passes through a series of fractionating columns in which liquids are heated at the bottom and partly vaporised, and gases are cooled and condensed at the top of the column. Gas flows up the column and liquid flows down through the column, coming into close contact at trays in the column. Lighter components are stripped to the top and heavier products stripped to the bottom of the tower. 

In certain circumstances it may be necessary to introduce a short fractionating column between the flask and the condenser the thermometer is then inserted at the top of the column. 

Attention is directed to the fact that ether is highly inflammable and also extremely volatile (b.p. 35°), and great care should be taken that there is no naked flame in the vicinity of the liquid (see Section 11,14). Under no circumstances should ether be distilled over a bare flame, but always from a steam bath or an electrically-heated water bath (Fig.//, 5,1), and with a highly efficient double surface condenser. In the author s laboratory a special lead-covered bench is set aside for distillations with ether and other inflammable solvents. The author s ether still consists of an electrically-heated water bath (Fig. 11, 5, 1), fitted with the usual concentric copper rings two 10-inch double surface condensers (Davies type) are suitably supported on stands with heavy iron bases, and a bent adaptor is fitted to the second condenser furthermost from the water bath. The flask containing the ethereal solution is supported on the water bath, a short fractionating column or a simple bent still head is fitted into the neck of the flask, and the stUl head is connected to the condensers by a cork the recovered ether is collected in a vessel of appropriate size. 

Sulphuric acid method. Place 20 g. of commercial cycZohexanol and 0-6 ml. of concentrated sulphuric acid in a 150 or 200 ml. round-bottomed or bolt head flask, add 2-3 chips of porous porcelain, and mix well. Fit the flask with a fractionating column, a Liebig condenser, adapter and filter flask receiver as in Section 111,10 (1). Heat the flask in an air bath (Fig. II, 5, 3) at such a rate that the temperature at the top of the column does not rise above 90° alternatively, an oil bath, heated to a temperature of 130-140°, may be used. Stop the distillation when only a small residue remains and the odour of sulphur dioxide is apparent. Transfer the distillate to a small separatory funnel. 

Fit a 750 ml. round-bottomed flask with a fractionating column attached to a condenser set for downward distillation. Place 500 g. of diacetone alcohol (the crude product is quite satisfactory), 01 g. of iodine and a few fragments of porous porcelain in the flask. Distil slowly. with a small free flame (best in an air bath) and collect the following fractions (a) 56-80° (acetone and a little mesityl oxide) (6) 80-126° (two layers, water and mesityl oxide) and (c) 126-131° (mesityl oxide). Whilst fraction (c) is distilling, separate the water from fraction (6), dry with anhydrous potassium carbonate or anhydrous magnesium sulphate, and fractionate from a small flask collect the mesityl oxide at 126-131°. The yield is about 400 g. 

Place 146 g. of adipic acid, 360 ml, (285 g.) of absolute ethyl alcohol 180 ml. of toluene and 1 - 5 g. of concentrated sulphuric acid in a 1-litre round-bottomed flask, attach a short fractionating column connected to a downward condenser, and heat in an oil bath at 115°, When the acid... 

Place 200 g, (250 ml.) of rectified spirit in a 1-litre round-bottomed flask fitted with a reflux condenser. Cool in ice and run in, slowly and with frequent shaking, 200 g. (109 ml.) of concentrated sulphuric acid. Add 83 g. (104 ml.) of -butyl cyanide (Section 111,113) to the mixture and reflux the whole for 10 hours. Allow to cool, pour the reaction mixture into ice water, separate the upper layer of ester and alcohol, and dry over anhydrous magnesium or calcium sulphate. Distil through a fractionating column and collect the ethyl n-valerate at 143-146°. A further amovmt of the pure ester may be obtained by redrying the fraction of low boiling point and redistilling. The yield is 110 g. 

Cool the mixture and decant the solution from the sodium bromide wash the salt with two 20 ml. portions of absolute alcohol and add the washings to the main solution. Distil off the alcohol, which contains the slight excess of n-propyl bromide used in the condensation, through a short fractionating column from a water bath. The residue A) of crude ethyl n-propylacetoacetate may be used directly in the preparation of methyl n-butyl ketone. If the fairly pure ester is required, distil the crude product under diminished pressure and collect the fraction boihng at 109-113727 mm. (183 g.) (R). 

Tricarballylic acid. Place 228 g. (204 ml.) of ethyl propane-1 1 2 3-tetracarboxylate and 240 ml. of 1 1 hydrochloric acid in a 1-litre threenecked flask, fitted with a mechanical stirrer and a fractionating column with condenser set for downward distillation attach a receiver with side tube to the condenser and connect the side tube to a wash bottle containing water. Boil the mixture, with continual stirring, at such a rate that the... 

Alternatively, an independent column (Fig. XII, 2, 8, c) may be inserted into a flask the column may be of the Vigreux, Widmer or Hempel form. The fractionating column should be lagged with asbestos cloth or string for distillation temperatures above 100° for the best results the column should be heated electrically (compare Section 11,15) to a temperature 5-10° below the b.p. of the fraction being collected. The side arm of the flask or fractionating column may be attached to a cold spot condenser and receiver as in Fig. XII, 2, 4 or to a Liebig s condenser and receiver as in Fig. XII, 2, 1. 

The commercial production equipment consists of a furnace, heat-exchanger tubes, a fractionating column packed with Rachig rings, a KCl feed, a waste removal system, and a vapor condensing system (Fig. 1). 

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