Description
1-Hexadecanol is odorless.
Chemical Properties
1-Hexadecanol is odorless.
Chemical Properties
Cetyl alcohol occurs as waxy, white flakes, granules, cubes, or
castings. It has a faint characteristic odor and bland taste.
Chemical Properties
white solid
Originator
Hexadecyl alcohol,Esso Res. And
Eng. Co.
Occurrence
Reported as a major constituent of spermaceti oil, where it is present chiefy as cetyl palmitate Also reported found in guava, peach, pear, kohlrabi, baked potato, mustard, Parmesan cheese, butter, milk powder, boiled egg, cooked chicken, roasted beef, beef fat, whiskies, tea, starfruit, mango, rice, licorice, kiwifruit, loquat, endive, shrimp, crab, clam, Cape gooseberry and pawpaw
Definition
ChEBI: A long chain fatty alcohol that is hexadecane substituted by a hydroxy group at position 1.
Production Methods
Cetyl alcohol may be manufactured by a number of methods such as
esterification and hydrogenolysis of fatty acids or by catalytic
hydrogenation of the triglycerides obtained from coconut oil or
tallow. Cetyl alcohol may be purified by crystallization and
distillation.
Manufacturing Process
1). A slurry of sodium bicarbonate comprising 39.8 g sodium bicarbonate and
254 ml water was placed in an autoclave. 96.3 g hexadecyl bromide and 635
ml acetone were then added. The autoclave was sealed and while stirring (590
r.p.m.) it was heated to a temperature of 218°C over a period of 1 hour 15
min. The temperature was maintained at 218-220°C for an additional hour. At
the end of the reaction the autoclave was cooled to about 50°C, that is, to a
temperature at which the alcohol remains molten. The autoclave was then
rinsed with acetone and 1 N hydrochloric acid add to neutralize the sodium
bicarbonate. The reaction mixture was diluted with an equivalent volume of
water and then extracted with n-pentane. (Other suitable water insoluble
solvents such as benzene, carbon tetrachloride, chloroform, petroleum ether
and the like can be used for extraction). The pentane extract was washed with
water and then dried over magnesium sulfate. The dried solution was filtered
and evaporated. The residue was melted and a vacuum applied to remove the
last traces of pentane. On distillation a yield of 94.8% of the theoretical yield
white crystals of hexadecanol was recovered; M.P. 49°C, B.P. 344°C, nD79 =
1.4283.
2). 5.80 g of hexadecyl bromide, 36 ml of 60% aqueous dioxane and 0.73 g
of calcium oxide were placed in an ampoule. The ampoule was then heated,
while shaking, to a temperature of 220°C over a period of 0.5 hours, and
maintained at this temperature for 1 hour. After the reaction the ampoule was
cooled and the products worked up as in method 1. Analysis for alcohol
content by Zerewitinoff active hydrogen determination showed the yield to be
92.5%; M.P. 49°C, B.P. 344°C, nD79 = 1.4283.
3). A solution of palmitoyl chloride in dioxane was added dropwise to a cooled
dispersion of sodium borohydride.The mixture was heated on the steam bath
for a short time and then, after cooling, water was added. On distillation a
yield of hexadecanol 87%, M.P. 49°C, B.P. 344°C.
Therapeutic Function
Pharmaceutic aid
General Description
Cetyl alcohol is a long chain alcohol, which can find applications as an emulsifying agent, emollient, viscosity increasing agent, foam booster and opacifying agent in pharmaceuticals and cosmetics.
Flammability and Explosibility
Notclassified
Pharmaceutical Applications
Cetyl alcohol is widely used in cosmetics and pharmaceutical
formulations such as suppositories, modified-release solid dosage
forms, emulsions, lotions, creams, and ointments.
In suppositories cetyl alcohol is used to raise the melting point of
the base, and in modified-release dosage forms it may be used to
form a permeable barrier coating. In lotions, creams, and ointments
cetyl alcohol is used because of its emollient, water-absorptive, and
emulsifying properties. It enhances stability, improves texture, and
increases consistency. The emollient properties are due to absorption
and retention of cetyl alcohol in the epidermis, where it
lubricates and softens the skin while imparting a characteristic
‘velvety’ texture.
Cetyl alcohol is also used for its water absorption properties in
water-in-oil emulsions. For example, a mixture of petrolatum and
cetyl alcohol (19 : 1) will absorb 40–50% of its weight of water.
Cetyl alcohol acts as a weak emulsifier of the water-in-oil type, thus
allowing a reduction of the quantity of other emulsifying agents
used in a formulation. Cetyl alcohol has also been reported to
increase the consistency of water-in-oil emulsions.
In oil-in-water emulsions, cetyl alcohol is reported to improve
stability by combining with the water-soluble emulsifying agent.
The combined mixed emulsifier produces a close packed, monomolecular
barrier at the oil–water interface which forms a
mechanical barrier against droplet coalescence.
In semisolid emulsions, excess cetyl alcohol combines with the
aqueous emulsifier solution to form a viscoelastic continuous phase
that imparts semisolid properties to the emulsion and also prevents
droplet coalescence. Therefore, cetyl alcohol is sometimes referred
to as a ‘consistency improver’ or a ‘bodying agent’, although it may
be necessary to mix cetyl alcohol with a hydrophilic emulsifier to
impart this property.
It should be noted that pure or pharmacopeial grades of cetyl
alcohol may not form stable semisolid emulsions and may not show
the same physical properties as grades of cetyl alcohol that contain
significant amounts of other similar alcohols.
Safety
Cetyl alcohol is mainly used in topical formulations, although it has
also been used in oral and rectal preparations.
Cetyl alcohol has been associated with allergic delayed-type
hypersensitivity reactions in patients with stasis dermatitis. Crosssensitization
with cetostearyl alcohol, lanolin, and stearyl alcohol
has also been reported. It has been suggested that hypersensitivity
may be caused by impurities in commercial grades of cetyl
alcohol since highly refined cetyl alcohol (99.5%) has not been
associated with hypersensitivity reactions.
LD50 (mouse, IP): 1.6 g/kg
LD50 (mouse, oral): 3.2 g/kg
LD50 (rat, IP): 1.6 g/kg
LD50 (rat, oral): 5 g/kg
storage
Cetyl alcohol is stable in the presence of acids, alkalis, light, and air;
it does not become rancid. It should be stored in a well-closed
container in a cool, dry place.
Purification Methods
Crystallise the alcohol from aqueous EtOH or from cyclohexane. Alternatively purify it by zone refining. The purity can be checked by gas chromatography. [Beilstein 1 H 429, 1 I 219, 1 II 466, 1 III 1815, 1 IV 1876.]
Incompatibilities
Incompatible with strong oxidizing agents. Cetyl alcohol is
responsible for lowering the melting point of ibuprofen, which
results in sticking tendencies during the process of film coating
ibuprofen crystals.
Regulatory Status
Included in the FDA Inactive Ingredients Database (ophthalmic
preparations, oral capsules and tablets, otic and rectal preparations,
topical aerosols, creams, emulsions, ointments and solutions, and
vaginal preparations). Included in nonparenteral medicines licensed
in the UK. Included in the Canadian List of Acceptable Nonmedicinal
Ingredients.