A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1926, 6, 54
DOI: 10.15227/orgsyn.006.0054
Submitted by E. E. Dreger
Checked by Roger Adams and G. S. Hiers.
1. Procedure
In a 5-l. round-bottomed flask, fitted with a stirrer, separatory funnel, and a reflux condenser to the upper end of which a calcium chloride tube is attached, is placed 150 g. (6.2 atoms) of magnesium turnings. A small crystal of iodine (Note 1) and about 100 cc. of a mixture of 822 g. (6 moles) of n-butyl bromide (p. 28) and 2 l. of anhydrous ethyl ether are added. As soon as the reaction starts, 350 cc. of anhydrous ether is added, and the remainder of the n-butyl bromide solution is dropped in at such a rate that the mixture boils continuously. The time of addition (one and one-half hours) may be decreased by cooling the flask externally. Stirring is started as soon as enough liquid is present in the flask.
When all has been added (Note 2), 278 g. (6.3 moles) of ethylene oxide (Note 3) (previously dried with soda lime) is added through a tube (3 or 4 mm. in diameter) the end of which is about 20 mm. above the surface of the liquid (Note 4), the temperature being kept below 10° by cooling in an efficient ice-and-salt bath (Note 5). This addition requires four to six hours. When all has been added the ice bath is removed; the temperature of the mixture generally rises enough to cause gentle boiling. When this ceases the mixture is warmed on a steam bath for one hour longer.
The condenser is then arranged for downward distillation, and when about 1 l. of ether has distilled (Note 6) the receiver is changed and 1 l. of dry benzene (Note 7) is added; distillation is continued with stirring until the temperature of the distilling vapor reaches 65°. The mixture is then boiled under reflux for one hour. Usually by this time it has become so viscous that stirring is no longer efficient. The mixture is then allowed to cool and is decomposed with 2 l. of an ice-water mixture. The precipitated magnesium hydroxide is dissolved by adding a sufficient quantity of 30 per cent sulfuric acid and enough ice to keep the mixture cold.
The mixture of benzene and hexyl alcohol is now distilled in a current of steam; about 7 l. of distillate must be collected before all the product is distilled. The oily layer is separated and the watery portion distilled until free of hexyl alcohol. The oil so obtained is added to the main quantity and the watery portion again distilled. The united product is now stirred on the steam bath for one to two hours with 1 l. of 20 per cent sodium hydroxide solution and again subjected to steam distillation, as before. The oily product so obtained is then distilled under atmospheric pressure with the use of a good fractionating column. The fraction boiling up to 85° is mostly benzene and water. The fraction boiling between 85° and 154° is collected separately for redistillation, and the fraction boiling at 154–157° collected as pure material. There is practically no high-boiling residue. The yield (Note 7) is 368–380 g. (60–62 per cent of the theoretical amount) (Note 8).
2. Notes
1. The reaction between the ethereal solution of n-butyl bromide and the magnesium frequently starts without any assistance, but the presence of a trace of iodine is of no disadvantage and renders more certain the beginning of the reaction.
2. The butyl bromide appears to react as fast as it is added, so that there is no need of stirring or warming the butylmagnesium bromide solution before adding the ethylene oxide. The small amount of unattacked magnesium has no influence on the subsequent reactions.
3. A convenient arrangement consists of placing the ethylene oxide tank on suitable scales and noting the proper decrease in weight. The gas may be passed through a short tower filled with soda lime and then through a spiral condenser surrounded with salt and ice.
4. If the mouth of the delivery tube is beneath the surface, troublesome clogging occurs.
5. The first reaction appears to consist of the formation of an oxonium addition product of the ethylene oxide and the butylmagnesium bromide.
6. Careful watching is necessary at this point, since if the distillation is carried too far a violent reaction, apparently a rearrangement of the initial addition product, may set in.
7. By the use of benzene as a diluent the reaction referred to in (Note 6) takes place smoothly and without violence; without it the yield is only about 200 g.
8. Instead of adding the condensed ethylene oxide, it may be dissolved in 350 cc. of chilled anhydrous ether which is added during the course of one to two hours. In this case, however, the yields are lower, apparently owing to the vaporization of some of the ethylene oxide.
3. Discussion
n-Hexyl alcohol can be prepared by the reduction of ethyl caproate by sodium and absolute alcohol1 alone or in anhydrous ammonia solution;2 by the reduction of n-caproamide by sodium and absolute alcohol;3 by the reduction of n-caproaldehyde by sodium amalgam in dilute sulfuric acid;4 by the action of nitrous acid on n-hexylamine;5 by the interaction of n-propylmagnesium bromide and trimethylene oxide,6 benzene being employed as a diluent; and by the procedure described.7
This preparation is referenced from:

References and Notes
  1. Henry, Bull. sci. acad. roy. Belg. 158, 77 (1905) [Chem. Zentr. II, 214 (1905)]; Blaise and Luttringer, Bull. soc. chim. (3) 33, 826 (1905); Bouveault and Blanc, Ger. pat. 164,294 [Chem. Zentr. II, 1700 (1905)].
  2. Chablay, Compt. rend. 156, 1020 (1913).
  3. Bouveault and Blanc, ibid. 138, 149 (1904).
  4. Lieben and Janecek, Ann. 187, 135 (1877).
  5. Frentzel, Ber. 16, 744 (1883).
  6. Derick and Bissell, J. Am. Chem. Soc. 38, 2484 (1916).
  7. Vaughn, Spahr, and Nieuwland, J. Am. Chem. Soc. 55, 4207 (1933).

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

soda lime

oxonium addition product of the ethylene oxide

alcohol (64-17-5)

sulfuric acid (7664-93-9)

ammonia (7664-41-7)

Benzene (71-43-2)

ethyl ether (60-29-7)

sodium hydroxide (1310-73-2)

magnesium turnings (7439-95-4)

Butyl bromide,
n-butyl bromide (109-65-9)

nitrous acid (7782-77-6)

iodine (7553-56-2)

sodium (13966-32-0)

Ethylene oxide (75-21-8)

magnesium hydroxide

Hexyl alcohol,
n-HEXYL ALCOHOL (111-27-3)

Butylmagnesium bromide (693-03-8)

ethyl caproate (123-66-0)



Trimethylene oxide (503-30-0)

n-propylmagnesium bromide

n-hexylamine (111-26-2)