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Org. Synth. 1940, 20, 50
DOI: 10.15227/orgsyn.020.0050
n-DODECYL (LAURYL) p-TOLUENESULFONATE
Submitted by C. S. Marvel and V. C. Sekera.
Checked by C. F. H. Allen and C. V. Wilson.
1. Procedure
In a 1-l. three-necked flask fitted with a stirrer and thermometer are placed 93 g. (0.5 mole) of dodecanol (Note 1) and 158 g. (2 moles) of pyridine. The flask is surrounded by a water bath sufficiently cold to lower the temperature of the mixture to 10°. At this temperature 105 g. (0.55 mole) of p-toluenesulfonyl chloride is added in portions over a 20- to 30-minute period, or at such a rate that the temperature does not exceed 20° at any time. The mixture is then stirred for 3 hours at a temperature below 20°, after which it is diluted with 300 ml. of hydrochloric acid (sp. gr. 1.19) in 1 l. of ice water. The ester which crystallizes is collected on a chilled Büchner funnel and sucked as dry as possible. The solid is transferred to a 600-ml. beaker, 250–300 ml. of methanol is added, and the mixture is warmed on the steam bath until the ester melts. It is then cooled in a freezing mixture while being stirred continuously; the ester separates in a fairly fine state. It is then collected on a chilled funnel and allowed to dry in the air, preferably at a temperature below 20°. The yield of ester is 152–156 g. (88–90% based upon the dodecanol used). It melts at 20–25° (Note 2) and is sufficiently pure for most purposes.
If a purer product is desired, it is recrystallized from petroleum ether (b.p. 30–60°), using 4 ml. per 3 g., and drying over anhydrous sodium sulfate. The solution is chilled to 0° and the ester filtered on a chilled funnel; the recovery is 90%, and the melting point is 28–30°. Evaporation of the solvent to a small volume deposits an additional amount (Note 3).
2. Notes
1. Dodecanol (lauryl alcohol), m.p. 20–22°; pyridine, b.p. 113–115°; and p-toluenesulfonyl chloride, m.p. 66–68°, are used.
2. The ester contains traces of water, which makes the melting point unreliable; the freezing point is 24–25°.
3. The following esters have been made in essentially the same yields; butyl p-toluenesulfonate [Org. Syntheses Coll. Vol. 1, 145 (1941)]; n-tetradecyl p-toluenesulfonate, m.p. 35°; n-hexadecyl p-toluenesulfonate, m.p. 49°; n-octadecyl p-toluenesulfonate, m.p. 56°; n-decyl p-bromobenzenesulfonate, m.p. 43–44°; n-dodecyl p-bromobenzenesulfonate, m.p. 49°; n-tetradecyl p-bromobenzenesulfonate, m.p. 51.5°; n-hexadecyl p-bromobenzenesulfonate, m.p. 60°; n-octadecyl p-bromobenzenesulfonate, m.p. 64–65°.
3. Discussion
n-Dodecyl p-toluenesulfonate has been prepared only by the action of p-toluenesulfonyl chloride on dodecanol-1 in the presence of pyridine1 according to the general procedure developed by Patterson and Frew2 for making esters of sulfonic acids.
This preparation is referenced from:

References and Notes
  1. Sekera and Marvel, J. Am. Chem. Soc., 55, 345 (1933).
  2. Patterson and Frew, J. Chem. Soc., 89, 332 (1906).

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

petroleum ether

hydrochloric acid (7647-01-0)

methanol (67-56-1)

Lauryl alcohol,
dodecanol,
dodecanol-1 (112-53-8)

sodium sulfate (7757-82-6)

pyridine (110-86-1)

p-Toluenesulfonyl chloride (98-59-9)

n-Dodecyl p-toluenesulfonate (10157-76-3)

Butyl p-toluenesulfonate (778-28-9)

n-DODECYL (LAURYL) p-TOLUENESULFONATE

n-tetradecyl p-toluenesulfonate

n-hexadecyl p-toluenesulfonate

n-octadecyl p-toluenesulfonate (3386-32-1)

n-decyl p-bromobenzenesulfonate

n-dodecyl p-bromobenzenesulfonate

n-tetradecyl p-bromobenzenesulfonate

n-hexadecyl p-bromobenzenesulfonate

n-octadecyl p-bromobenzenesulfonate