At this site on May 2, 1892, while searching for an economical process
to make aluminum, Canadian inventor Thomas L. Willson (1860-1915) accidentally discovered the electric-arc process for preparing calcium carbide, which reacts with water to form acetylene.  The first commercial calcium carbide plant, built by local entrepreneur James Turner Morehead (1840-1908), operated here between 1894 and 1896.  From this beginning, calcium carbide manufacturing spread around the world.  Acetylene, used first for lighting homes, railways, mines, and marine buoys and then for oxyacetylene welding, became one of the foundations of the synthetic organic chemicals industry.

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 Wöhler. 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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