1-Octanol Explained

1-Octanol, also known as octan-1-ol, is the organic compound with the molecular formula CH3(CH2)7OH. It is a fatty alcohol. Many other isomers are also known generically as octanols. 1-Octanol is manufactured for the synthesis of esters for use in perfumes and flavorings. It has a pungent odor. Esters of octanol, such as octyl acetate, occur as components of essential oils. It is used to evaluate the lipophilicity of pharmaceutical products.

Preparation

Octanol is mainly produced industrially by the oligomerization of ethylene using triethylaluminium followed by oxidation of the alkylaluminium products. This route is known as the Ziegler alcohol synthesis.[1] An idealized synthesis is shown:

Al(C2H5)3 + 9 C2H4 → Al(C8H17)3

Al(C8H17)3 + 3 O + 3 H2O → 3 HOC8H17 + Al(OH)3The process generates a range of alcohols, which can be separated by distillation.

The Kuraray process defines an alternative route to 1-octanol, but using C4 + C4 building strategy. 1,3-Butadiene is dimerized concomitant with the addition of one molecule of water. This conversion is catalyzed by palladium complexes. The resulting doubly unsaturated alcohol is then hydrogenated.

Water/octanol partitioning

See main article: Octanol-water partition coefficient. Octanol and water are immiscible. The distribution of a compound between water and octanol is used to calculate the partition coefficient, P, of that molecule (often expressed as its logarithm to the base 10, log P). Water/octanol partitioning is a relatively good approximation of the partitioning between the cytosol and lipid membranes of living systems.[2]

Many dermal absorption models consider the stratum corneum/ water partition coefficient to be well approximated by a function of the water/octanol partition coefficient of the form:[3]

log(Ksc/w)=a+blog(Kw/o)

Where a and b are constants,

Ksc/w

is the stratum corneum/water partition coefficient, and

Kw/o

is the water/octanol partition coefficient. The values of a and b vary between papers, but Cleek & Bunge[4] have reported the values a = 0, b = 0.74.

Properties and uses

With a flash point of 81 °C, 1-octanol is not seriously flammable, though its autoignition temperature is as low as 245 °C. 1-Octanol is mainly consumed as a precursor to perfumes.[1] It has been examined for controlling essential tremor and other types of involuntary neurological tremors because evidence indicates it can relieve tremor symptoms at lower doses than are required to obtain a similar level of symptomatic relief from consumption of ethanol, thereby reducing the risk alcohol intoxication at therapeutic dosages.[5]

1-Octanol hydrogen bonds to Lewis bases. It is a Lewis acid in the ECW model and its acid parameters are EA = 0.85 and C A = 0.87.[6]

See also

Notes and References

  1. Falbe . Jürgen . Bahrmann . Helmut . Lipps . Wolfgang . Mayer . Dieter . Frey . Guido D. . Alcohols, Aliphatic . Ullmann's Encyclopedia of Industrial Chemistry . 2013 . 10.1002/14356007.a01_279.pub2 . 978-3527306732 . American Cancer Society . en.
  2. Book: Schwarzenbach . Rene P. . Gschwend . Philip M. . Imboden . Dieter M. . Environmental organic chemistry . . 2003 . 0-471-35053-2 . Environmental organic chemistry .
  3. McCarley KD, Bunge AL . Pharmacokinetic Models of Dermal Absorption . Journal of Pharmaceutical Sciences . 90 . 11 . 1699–1719 . 2001 . 11745728 . 10.1002/jps.1120.
  4. Cleek RL, Bunge AL . A new method for estimating dermal absorption from chemical exposure. 1. General approach . Pharmaceutical Research . 10 . 4 . 497–506 . 1993 . 8483831 . 10.1023/A:1018981515480. 24534572 .
  5. Bushara K. . Pilot trial of 1-octanol in essential tremor . Neurology . 2004 . 62 . 122–124 . 14718713 . 1 . 10.1212/01.wnl.0000101722.95137.19. 9015641 . etal.
  6. Vogel . Glenn C. . Drago . Russell S. . 1996 . The ECW Model . Journal of Chemical Education . en . 73 . 8 . 701 . 10.1021/ed073p701 . 1996JChEd..73..701V . 0021-9584.