Petrolatum (peh-tro-LAY-tum) is a mixture, not a compound.
Mixtures differ from compounds in a number of
important ways. The parts making up a mixture are not
chemically combined with each other, as they are in a compound.
Also, mixtures have no definite composition, but
consist of varying amounts of the substances from which
they are formed.
Petrolatum is a complex mixture of hydrocarbons
derived from the distillation of petroleum. Hydrocarbons
are compounds that contain only carbon and hydrogen. The
hydrocarbons that make up petrolatum belong to the
methane (saturated or alkane) family of hydrocarbons with
the general formula CnH2N+2. Some members of the family
include methane (CH4), ethane (C2H5), propane (C3H8), and
butane (C4H10).
Petrolatum occurs in a semi-solid or liquid form. The
semi-solid form is also called petroleum jelly or mineral jelly
and is commercially available under a number of trade
names, including Kremoline, Pureline, Sherolatum, and
VaselineTM. It ranges in color from white to yellowish to
amber. It is practically odorless and tasteless. It melts over a
wide range, from about 38 C to about 55 C (100 F to 131 F).
The liquid form is also known as liquid paraffin, mineral
oil, or white mineral oil. Such products are sold commercially
under trade names such as Alboline, Drakeol, Frigol,
Kremol, and Paroleine. It is a colorless, tasteless, and odorless
oily liquid.
Oil was first discovered in the United States in the 1850s
in western Pennsylvania. A chemist from Brooklyn, New
York, Robert Augustus Chesebrough (1837–1938), visited
the new wells and noticed a wax-like material sticking
to the petroleum drilling rods. He learned that oil workers
used the ‘‘rod wax’’ to heal burns on their skin. Chesebrough
eventually extracted and purified the substance—petrolatum—
from petroleum and began manufacturing it in 1870. He
received several patents for his discovery and in 1878, he
gave his product the trade name of VaselineTM. His product
quickly became popular as an ointment for wounds and
burns. Unlike the animal and vegetable oils then being used
for that purpose, petrolatum did not spoil. By the late 1870s,
VaselineTM was selling at the rate of one jar everyminute in
the United States. In 1880, it was added to the U.S. Pharmacopoeia,
a manual that lists drugs used in medical practice.
Petrolatum is a product of the fractional distillation of
crude oil. Crude oil is a complex mixture of hundreds or
thousands of compounds. These compounds can be separated,
or distilled, from each other by heating crude oil to high
temperatures. As the temperature of the crude oil rises,
various groups or a ‘‘fraction’’ of compounds boil off. The first
group of compounds includes gaseous compounds dissolved
in crude oil. The next group of compounds includes compounds
with low boiling points. The next group of compounds
includes compounds with slightly higher boiling
points. And so on. Eventually, a tar-like mass of compounds
with very high boiling points is left behind in the distilling
tower. This residue is heated to separate liquids from solids
remaining behind. Some of these liquids and solids make up
the semi-solid and liquid forms of petrolatum.
Petrolatum has a wide variety of uses, ranging from
personal care and medical applications to industrial uses.
The solid form, such as VaselineTM is used as a topical ointment
for the treatment of dry, cracked skin and to reduce the
risk of infection. It works as a moisturizing agent because it
reduces water loss from the skin, It helps prevent infection
because it creates a barrier over wounds that prevents disease-
causing organisms from entering the body. Solid petrolatum
is also an ingredient in many skin care and cosmetic
products, such as skin lotions, body and facial cleansers, antiperspirants,
lipsticks, lip balms, sunscreens, and after-sun
lotions. In hair products, it helps smooth frizzy hair by
allowing hair to retain its natural moisture. The formation
used in most of these products remains virtually unchanged
from that developed by Robert Chesebrough in the 1800s.
Solid petrolatum is also used in industrial applications
for a variety of purposes, such as:
• As a softener in the production of rubber products;
• In the food processing industry, to coat raw fruits and
vegetables and to help products retain moisture;
• As a defoaming agent in the production of beet sugar
and yeasts;
• For the lubrication of firearms and machine parts;
• In the production of modeling clays;
• In the manufacture of candles, to prevent a candle from
shrinking as it cools after being burned;
• In the preparation of shoe polishes; and
• As an ingredient in rust preventatives.
The primary use of liquid petrolatum is as a laxative, a
product that loosens the bowels. It also has a number of other
applications, such as an additive in foods such as candies,
confectionary products, and baked goods; as an ingredient in
personal care products, such as baby oil creams, hair conditioning
lotions, and ointments; in many different kinds of
pharmaceutical preparations; in the production of industrial
lubricants; as a softening agent in the manufacture of rubber,
textiles, fibers, adhesives, and machine parts; as dust
suppressants; and as dehydrating agents for a number of
industrial processes.
