Industrial
Processes Discovered By Chance
May 2,
1998, marked the 106th anniversary of an unexpected discovery in the
village of Spray (now Eden), North Carolina, that proved to be a milestone
in the history of the chemical industry. On that date, Thomas L. Willson,
a struggling young Canadian inventor, accidentally discovered the
processes for making calcium carbide and acetylene in commercial quantities.
Acetylene,
when burned in air, gave a light far brighter than any in use at
the time for home lighting. When burned with oxygen, it gave a flame
that was 1000 ¯C hotter than any other, leading to the development
of commercial oxyacetylene welding and cutting. Most importantly,
acetylene later became the starting material in the synthesis of
hundreds of aliphatic organic chemicals used worldwide, particularly
solvents, plastics, and synthetic rubber.
Thomas
Leopold Willson (1860-1915), discoverer of these processes, was
born in Princeton, Ontario, the grandson of John Willson, speaker
of the United Canadian Assembly. He attended Hamilton Collegiate
Institute; but after his father died, he withdrew from school to
develop an arc-lighting system, the first seen at Hamilton. At age
22, he moved to the United States where he held various jobs in
the mechanical and electrical trades before settling in Brooklyn,
New York, in 1887. His work over the next three years resulted in
six patents, which secured for him the rights in the United States
for use of the electric-arc furnace in ore smelting. Aluminum metal
was a primary target.
In
December 1890, the Willson Aluminum Company was formed to exploit
Willson's patents. In 1891, Willson moved to Spray to build a small
300-horsepower plant along the Smith River on land owned by one
of the company's financial backers, James Turner Morehead (1840-1908).
Morehead, a graduate of the University of North Carolina and a Confederate
army veteran, was a textile manufacturer, land and water power developer,
and former state senator. Although most of Morehead's business ventures
prospered, failure of a railroad in which he had invested left him
deeply in debt. To raise cash, he looked for new uses for his abundant
supply of water power. This search led him to Willson.
Thomas
Willson was just one among many seeking an economical way to make
aluminum. His approach was to reduce the aluminum ore with carbon
in a high-temperature, electric-arc furnace, a process explored
in the laboratory at about the same time by the French chemist Henri
Moissan.
In
practice, Willson was able to produce only a few globules of aluminum.
He then reasoned that if he could make a more chemically active
metal, such as calcium, he could, in turn, use the calcium to reduce
alumina. Accordingly, on May 2, 1892, a mixture of lime (calcium
oxide) and coal tar (carbon) was subjected to the heat of the arc.
When the furnace was tapped and the resulting product thrown into
water, it produced a flammable gas thought to be hydrogen, as was
expected from calcium.
However,
unlike clean-burning hydrogen, this gas burned with a sooty flame,
for which there was no ready explanation. Willson then retained
Francis P. Venable (1856-1954), of the University of North Carolina,
as a consultant. During the summer and fall of 1892, Venable proved
that the furnace product was calcium carbide and that the gas as
it evolved with water was acetylene, a reaction identified in 1862
by the German chemist Friedrich W¦hler. Although there were no uses
for either calcium carbide or acetylene at the time, Willson filed
for a patent on this process on August 9, 1892.
Meanwhile,
the experimental work to make aluminum continued. By the spring
of 1893, however, it was obvious that Willson's process was a failure.
The stock market crash in May 1893 and the ensuing depression bankrupted
the company, leaving Morehead virtually penniless.
Failing
to find anyone willing to buy their calcium carbide and acetylene
patents, Morehead and Willson turned their attention to finding
and promoting uses for the products themselves, beginning with acetylene
in lighting. After they showed that acetylene could produce a flame
10 to 12 times brighter than that of coal gas, its use as an illuminant
developed rapidly. Willson made the first sale of calcium carbide,
1 ton, to Eimer and Amend, a New York chemical and apparatus supply
house, on January 29, 1894. Fortune smiled again when, in August
1894, they sold their patents for the use of carbide and acetylene
in lighting to a new firm, the Electrogas Company, but retained
the rights for chemical manufacturing. Electrogas Company, in turn,
began to sell carbide manufacturing rights worldwide. As part of
the agreement, Willson reserved all rights for Canada, and Morehead
bought a manufacturing franchise.
Willson
moved back to New York in the fall of 1893 and set up a laboratory
at Eimer and Amend to explore chemical uses for acetylene. After
making small quantities of chloroform and aldehydes, he filed for
a patent in February 1894 to cover the use of acetylene in the manufacture
of "hydrocarbon products."
By
borrowing more money, Morehead was able, in August 1894, to complete
at Spray the first commercial calcium carbide plant. Its 8-foot
high, double-sided furnace was capable of continuous operation.
While a charge of lime and tar was being processed on one side,
a completed run of carbide could be cooling on the other. The furnace
produced 1 ton of carbide every 24 hours, which yielded 4.8 cubic
feet of gas per pound, 80% of the theoretical. As publicity about
acetylene's possibilities soared, so did the demand for carbide.
On May 1, 1895, the plant began to operate around the clock. The
months that followed were giddy with success, but then disaster
struck; the Willson plant was destroyed by fire on March 29, 1896.
Morehead
built a much larger plant on the James River near Lynchburg, Virginia.
Almost simultaneously, he opened a plant at Kanawha Falls, West
Virginia, to make ferro-alloys, processes that had been developed
at Spray by Willson and Guillaume de Chalmot (1870-1899), the plant
superintendent. Eventually, Morehead sold his holdings to the Union
Carbide Company, which had been formed in 1898 to consolidate the
interests of the Electrogas Company. He paid off his debts and,
at his death, left an estate of $200,000.
Willson
returned to Canada in 1895, where he became one of its wealthiest
and best-known citizens. By 1896, he was constructing a carbide
plant at Merritton, Ontario, and later he built plants in Ottawa
and Shawinigan Falls. As he sold rights for carbide manufacture
to others, he developed many interests, forming new companies and
plants as he proceeded to produce hydroelectric power, acetylene-lighted
marine buoys, fertilizer, cement, ammonia, phosphoric acid, and
paper. He sold his marine buoy business in 1909 and his interests
in carbide manufacture to a new firm, Canada Carbide Company, formed
in 1911. He died of a heart attack in New York while raising money
for yet another project. His home in Woodstock, Ontario, is now
a national historic site, and his summer home on Meech Lake in Quebec
is a government conference center and retreat
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