Nicolas Leblanc discovered a commercially viable process for producing soda, or sodium carbonate, a necessary raw material in many industrial applications in the late 18th and 19th centuries. Leblanc never realized a profit from his invention, though, as the French Revolution brought about the seizure of his soda factory and the publication of his method, which other manufacturers used without paying royalties to Leblanc, whose patent was rendered moot by the revolution. Leblanc’s method of soda production remained in use for more than a century, as subsequent scientists made improvements to his methodology.
Leblanc was born an orphan at Ivoy-le-Pre, in Indre, France, probably on December 6, 1742. His guardian was a physician who encouraged Leblanc to follow in his footsteps, so the boy apprenticed to an apothecary before studying at the Ecole de Chirurgie in Paris to qualify to practice medicine. In 1780, Louis-Philippe-Joseph (later known as Philippe-Egalite, the duc d’Or-leans) appointed Leblanc as the Orleans family surgeon, a position that afforded him the time and financial backing to conduct his own independent research.
In 1775, the French Academie des Sciences had offered a monetary prize for the development of a commercially viable process for making soda from salt (both of which derive from sodium). The existing processes relied on resources such as potash, barilla shrubs from Spain, or seaweed, which were becoming scarce, whereas salt was plentiful. Soda was used to produce glass, soap, paper, and porcelain, industries that were expanding at the time, thus requiring more raw materials. New processes existed at the time, but none that was efficient enough for industrial application.
As early as 1783, Leblanc discovered his technique for creating soda from salt, or sodium chloride, which he would dissolved in sulfuric acid to form sodium sulfate, releasing hydrogen chloride in the process. He then roasted the salt cake (as sodium sulfate was known) with powdered coal and calcium carbonate (crushed chalk or limestone) to create "black ash." He then dissolved this dark residue in water to extract the sodium carbonate, which he reconstituted into crystal form by heat, leaving a waste by-product of calcium sulfide, known as "galligu."
The Academie des Sciences neglected to award Leblanc the prize money, though he did file a 15-year patent in 1791. By then, he had already established a company in partnership with the duke, as well as J. J. Dize and Henri Shee, and built a factory at St. Denis that produced some 350 tons of soda its first year. However, neither his patent nor his ownership of the company lasted long, interrupted by the eruption of the French Revolution.
In November 1793, Leblanc’s patron, the duc d’Orleans, was guillotined. The soda factory, which he had financed, was nationalized, and the Committee of Public Safety published Leblanc’s soda-preparation methods in the name of the revolution. Not only did Leblanc forfeit profits from his own production of soda (the St. Denis factory distributed its production to the state at no profit), but also he lost the rights to royalties from the use of his method to produce soda. He sank into poverty while fighting to regain control over his discovery.
Leblanc had performed early investigations on crystallization, and now, in 1802, he published his findings in his only book, Cristallotechnie. Also in that year, Napoleon returned the soda factory to Leblanc; however, in the absence of funds to make capital improvements, it proved untenable to run the factory. Leblanc hedged his bets on receiving ample compensation for his losses, but when his claim was decided in November 1805, the award fell far short of his projected need. Depressed by the outcome of this decision, and downtrodden in poverty, Leblanc committed suicide at St. Denis on or about January 16, 1806.
No records document Leblanc’s inspiration for this discovery, as it does not follow logically from his previous investigations. In fact, it laid Leblanc open to claims against his propriety in this discovery. In 1810, Dize published an article claiming a share of Leblanc’s discovery. However, a special commission appointed by the Academie des Sciences convened in 1836 and concluded that Leblanc held sole claim to the discovery, based on the existing evidence.
