A -Butyl Bromide

The n-butyl bromide layer should be on top. If the reaction is not yet complete, the remaining n-butyl alcohol will sometimes form a second organic layer on top of the n-butyl bromide layer. Treat both organic layers as if they were one. Remove and discard as much of the aqueous (bottom) layer as possible using a Pasteur pipette, but do not remove any of the organic layer (or layers). Ignore the salts during this 

When the distillation is complete (one or two drops remaining), weigh the vial, calculate the percentage yield, and determine a microscale boiling point (Technique 13, Section 13.2). Determine the infrared spectrum of the product using salt plates (Technique 25, Section 25.2). Submit the remainder of your sample in a properly labeled vial, along with the infrared spectrum, when you submit your report to the instructor. 

NOTE In the following procedures, it may be difficult to see the interfaces between layers because the refractive index of the product will be similar to the refractive indices of the extraction solvents. 

Using an automatic pipette or a dispensing pump, place 1.0 mL of f-pentyl alcohol (2-methyl-2-butanol, MW = 88.2) in a preweighed 5-mL conical vial. Reweigh the vial to determine the exact weight of alcohol delivered. 

NOTE Before shaking the conical vial vigorously in the next step, be sure that the capped vial does not leak. If it does leak, use a Pasteur pipette to mix the two layers. Draw up as much liquid as possible into the Pasteur pipette and then expel the liquid rapidly back into the conical vial. Continue this mixing for 3-4 minutes. 

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Bromobutane. Here it is listed strictly alphabetically as it is—with all the bromo-compounds—not as a butane, 1-bromo-, and only a cross reference as a butyl bromide. 

Butyl azodiformate, 44,18 a-Butyl bromide, preparation of -butyl Grignard reagent from, 41, 61 (-Butyl carbazate, 44, 20 conversion to (-butyl azidoformate, 44,15... 

Synonyms. Butylscopolamonii Bromidum Hyoscine-A-Butyl Bromide Scopolamine Butylbromide. 

Trifluoromethyl-l,3,4-thiadiazol-2-one, with a butyl bromide side chain at N-3, undergoes a ring transformation with secondary amines to give 1,3.4-thiadiazocines (56) <83HCA2714>. The reaction is thought to occur via addition of the amine to the carbonyl of the thiadiazol-2-one, as outlined in Scheme 35. A second product in the reaction is the 3-aminobutyl-thiadiazol-2-one resulting from direct nucleophilic displacement of the bromine with the amine. 

All chemicals used in these trials toluene, A-butyl bromide, sodiiun phenolate trihydrate (Na0Ph.3H20), tetrabutylammonium bromide ((C4H9)4 NBr)(TBAB) and butyl phenyl ether, were purchased from Sigma-Aldrich chemicals (U.K.). 

Run off the lower layer of bromide, dry it with calcium chloride (as in the above preparation of ethyl bromide) and finally distil the filtered bromide from a small flask, preferably through a short column. Collect the n-butyl bromide as a colourless liquid of b.p. 99-102°. Yield, 30 g. 

This acid mixture may be prepared (compare Section 11,49, 1) by placing 120 g. (37-5 ml.) of bromine and 130 g. of crushed ice in a 500 ml. flask, cooling the latter in ice, and passing sulphur dioxide (from a siphon of the liquefied gas) into the bromine layer at such a rate that the gas is completely absorb. The flask is shaken occasionally, and the flow of gas is stopped inunediately the red colour due to free bromine has disappeared the mixture will then have a yellow colour. The resulting acid mixture is equivalent to 260 g. of 48 per cent, hydrobromio acid to which 75 g. of concentrated sulphuric acid have been added it need not be dis. tilled for the preparation of n-butyl bromide. 

The crude bromide contains a little unchanged alcohol and is said to contain some n-butyl ether (b.p. 141°). The former is removed by washing with concen. trated hydrochloric acid and this purification process is satisfactory for most purposes. Both the alcohol and the ether are removed by washing with 11-12 ml. of concentrated sulphuric acid the butyl bromide is not affected by this reagent. 

Filter the dried product through a fluted filter paper or a small cotton wool plug supported in a funnel into a dry 50 ml. distilling flask, and distil on a wire gauze or from an air bath (Fig. 11, 5, 3). Collect the fraction, b.p. 100-103°. The yield of n-butyl bromide is 18-19 g. 

In a 200 ml. distilling flask place 64 g. (50 ml.) of dry n-butyl bromide and 80 g. of dry silver nitrite (1). Insert a reflux condenser, carrying a cotton wool (or calcium chloride) guard tube, into the mouth of the flask and close the side arm with a small stopper. Allow the mixture to stand for 2 hours heat on a steam bath for 4 hours (some brown fumes are evolved), followed by 8 hours in an oil bath at 110°. Distil the mixture and collect the fraction of b.p. 149-151° as pure 1-nitro-n-butane (18 g.). A further small quantity may be obtained by distilling the fractions of low boihng point from a Widmer flask. 

Into a 1500 ml. round-bottomed flask place 97-5 g. of finely-powdered sodium cyanide (1), 125 ml. of water, and a few chips of porous porcelain. Attach a reflux condenser and warm on a water bath until all the sodium cyanide dissolves. Introduce a solution of 250 g. (196 ml.) of n-butyl bromide (Sections 111,35 and 111,37) in 290 ml. of pure methyl alcohol, and reflux gently on a water bath for 28-30 hours. Cool to room temperature and remove the sodium bromide which has separated by filtration through a sintered glass funnel at the pump wash the crystals with about 100 ml. of methyl alcohol. Transfer the filtrate and washings to From n caproamide by SOClj method. 

The fact that n-butylbenzene can be prepared in reasonable yield by the action of sodium upon a mixture of bromohenzene and n-butyl bromide can be partly explained on the assumption that n-butyl bromide reacts with phenyl-sodium more rapidly than does bromobenzene. It is interesting to note that n-butylbenzene can be prepared either from benzylsodium and n-propyl bromide or from phenylsodium and n-butyl bromide (Section VI,29). 

To a solution of 0.30 mol of ethyllithium (note 1) in about 270 ml of diethyl ether (see Chapter II, Exp. 1) v/as added 0.30 mol of methoxyallene at -20°C (see Chapter IV, Exp. 4) at a rate such that the temperature could be kept between -15 and -2Q°C. Fifteen minutes later a mixture of 0.27 mol of >z-butyl bromide and 100 ml of pure, dry HMPT ivas added in 5 min with efficient cooling, so that the temperature of the reaction mixture remained below 0°C. The cooling bath was then removed and the temperature was allowed to rise. After 4 h the brown reaction mixture was poured into 200 ml of ice-water. The aqueous layer was extracted twice with diethyl ether. The combined solutions were washed with concentrated ammonium chloride solution (which had been made slightly alkaline by addition of a few millilitres of aqueous ammonia, note 2) and dried over potassium carbonate. After addition of a small amount (2-5 ml) of... 

To a vigorously stirred suspension of 2 mol of lithium amide in 2 1 of liquid atimonia (see II, Exp. 11) was added in 15 min 1 mol of propargyl alcohol (commercial product, distilled in a partial vacuum before use). Subsequently, 1 mol of butyl bromide was added dropwise in 75 min. After an additional 1.5 h, stirring was stopped and the ammonia was allovied to evaporate. To the solid residue were added 500 ml of ice-water. After the solid mass had dissolved, six extractions with diethyl ether were performed. The (unwashed) combined extracts were dried over magnesium sulfate and then concentrated in a water-pump vacuum. Distillation of the residue through a 40-cm Vigreux column afforded 2-heptyn-l-ol, b.p. 

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