Ascorbic Acid (The Vitamin C)

  Ascorbic acid (as-KOR-bik AS-id), or vitamin C, is one of
the most important dietary vitamins for humans because it
plays a crucial role in building collagen, the protein that
serves as a support structure for the body. It is a watersoluble
vitamin, which means that the body excretes any
excess vitamin C in the urine and cannot store a surplus.
For that reason, humans must consume vitamin C in their
daily diets. Vitamin C is found in many fruits and vegetables
and most kinds of fresh meat. Citrus fruits, such as oranges
and lemons, are especially rich in the compound.

Humans have known about the consequences of vitamin C
deficiency for centuries. People traveling long distances
on land or by sea often came down with an illness called
scurvy. The same illness struck people living in their own
homes during long winters. The disease was characterized by
pain and weakness in the joints, fatigue, bleeding gums,
tooth loss, slow healing of wounds, and bruising. These symptoms
were caused as the body’s connective tissue broke down

and small blood vessels ruptured. These symptoms began to
disappear as fresh foods became more available. If they did
not get enough fresh food in their diets, people could die of
scurvy.
Scurvy was common enough that many people searched
for its cause and cure. Sailors were especially vulnerable to

the disease, and the first recorded investigations involving
vitamin C were done by seafaring men. In 1536, French
explorer Jacques Cartier (1491–1557) cured his sailors of
scurvy by following the advice of Indians in Newfoundland,
feeding them extract of pine needles. Scottish physician
James Lind (1716–1794) began investigating the disease in
1747. He read many historical accounts of the diseases and
combined that information with his own observations to
deduce that scurvy occurred only among people with very
limited diets. He went on a ten-week sea voyage and fed the
solders various foods to see which ones were best at curing
scurvy. Citrus fruits proved to be most effective in preventing
the disease, a result that Lind reported in 1753. Captain
James Cook (1728–1779) led expeditions to the South Seas in
the late 1700s and kept his crew healthy by feeding them
sauerkraut. In 1795 the British navy began serving its sailors
a daily portion of lime juice, and two things happened: British
sailors stopped getting scurvy, and people began calling
sailors ‘‘limeys.’’
  Many people refused to believe that scurvy was caused by
a dietary deficiency, suggesting that it was instead the result
of eating bad food or lack of exercise. In 1907, Norwegian
biochemists Alex Holst (1861–1931) and Theodore Frohlich
conducted a study in which guinea pigs were fed an experimental
diet that caused them to develop scurvy. The link
between the vitamin and the disease was firmly established
by this research. Ascorbic acid was first isolated independently
by the Hungarian-American biochemist Albert Szent-
Gyo¨rgi (1893–1986) and the American biochemist Charles
Glen King (1896–1988) in 1932. It was synthesized a year
later by the English chemist Sir Walter Norman Haworth
(1883–1950) and the Polish-Swiss chemist Tadeusz Reichstein
(1897–1996), again working independently of each other.

  Plants and most animals (humans and guinea pigs being
two exceptions) synthesize vitamin C in their cells through a
series of reactions in which the sugar galactose is eventually
converted to ascorbic acid. For many years, the compound has
been made commercially by a process known as the Reichstein
process, named after its inventor Tadeusz Reichstein. This
process begins with ordinary glucose, which is converted to
another sugar, sorbitol, which is then fermented to obtain

yet another sugar, sorbose. The sorbose is then converted
step-by-step into a series of other products, the last of which
is ascorbic acid.
  Chemists have long been searching for an alternative to
the Reichstein process because it uses so much energy and
produces by-products that are hazardous to the environment.
In the 1960s, Chinese scientists developed a method
that involves only two steps in the synthesis of ascorbic
acid, and in the early 2000s, Scottish scientists were
attempting to develop a method that involved only a single
step using fermentation. Currently, however, the Reichstein
process remains the most popular method for making the
compound.

  The best known use of vitamin C is as a nutritional
supplement, taken to ensure that one receives his or her
daily minimum requirement of the vitamin. The recommended
daily allowance (RDA) of vitamin C for adults is 60
milligrams per day. Anyone who eats a well-balanced diet
that includes citrus fruits, tomatoes, and green leafy vegetables
probably does not need to take a vitamin supplement.
However, the amount of vitamin C one normally receives
from a supplement is unlikely to cause any harm.

  In addition to its nutritional uses, ascorbic acid has a
number of other industrial applications, including:
• As a food preservative;
• As a reducing agent in chemical processes;
• As a preservative in foods;
• As a color fixing agent in meats, helping meats keep
their bright red appearance;
• As an additive to bread dough, where it helps increase
the activity of yeast used in the dough; and
• As a treatment for abscission in citrus plants, the tendency
for a plant to lose its leaves, flowers, and fruits.

Petroleum

  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.