Nicolas Leblanc (1742-1806) was a French surgeon and chemist who discovered how to manufacture soda from common salt. The "Leblanc process" was key to making soap, glass and other products from soda ash.

Nicolas Leblanc was born on January 6, 1742, in Ivoy-le-Pre, France. His father, a minor official at an iron works, died in 1751. Leblanc was sent to Bourges to live with Dr. Bien, a close family friend. Under the influence of his guardian, Leblanc developed an interest in medicine. When Bien died in 1759, Leblanc enrolled at the Ecole de Chirurgie in Paris to study medicine.

Graduating with a master's degree in surgery, Leblanc opened a medical practice. He married in 1775, and the couple's first child followed four years later. Unable to provide adequately for his family on the medical fees he obtained from his patients, Leblanc in 1780 accepted a position as the private physician to the household of the Duke of Orleans, later known as the revolutionary figure Philippe Egalite.

During this time, the study of chemistry was becoming more popular. Leblanc, having obtained financial stability in a position that allowed him a substantial amount of free time, began conducting experiments. He started with the study of crystallization, primarily because the material required for the experiments was inexpensive. In March 1786 he sent his results to the Academy of Sciences, which recommended that Leblanc "consider the formation of a complete collection of crystallized salts" and that this research be supported by the government. However, because of the turmoil that followed the French Revolution, the Academy was dissolved before its recommendations could be followed.

In 1794 the Committee of Public Instruction offered to support Leblanc's research. However, the chaotic social situation again kept Leblanc from getting his work on a solid footing. Eventually, the Committee on Public Instruction did manage to get public funds to underwrite the publication of Leblanc's crystallization research, detailed in the 1802 work De la Cristallotechnie.

Jean Darcet, the chair of the chemistry department at the College de France, became aware of Leblanc's research in 1786 and suggested Leblanc work on the problem of the production of pure nickel. Not published until 12 years later, the results were relatively insignificant and inconclusive; however, the work is evidence of Leblanc's early interest in industrial chemistry.

The Soda Crisis

Of much greater importance was Leblanc's next project: the creation of soda from non-organic sources. At that time, the main source for soda was wood ashes, and the wood supply in industrial Europe was diminishing. As a result, most of the sodium carbonate that the French glass, textile, and soap industries needed was imported from Spain, at a substantial price. Other markets, such as Russia and North America, were too distant and shipping costs too high to provide a practical solution.

Although soda was already being industrially produced from salt, the process was neither efficient nor cost-effective. The development of an inexpensive method of preparing soda from sea salt--the cheapest and most obvious source--became a national imperative for France. In 1783 King Louis XVI ordered the Academy of Sciences to offer a reward for the invention of an economical method of decomposing sea salt on a large scale. Although the Academy was dissolved before any prize was awarded, the contest was surely an important factor in Leblanc's decision to turn his attention to soda.

Developed the Leblanc Process

Leblanc began his study of the development of sodium carbonate around 1784. After making some progress, Leblanc approached the Duke and requested his financial support. The Duke agreed on the condition that Darcet, a longtime consultant to the Duke, be included in the process. Leblanc was allowed to set up a laboratory at the College of Paris, and Darcet assigned J. Dize, his assistant, to collaborate with Leblanc.

The process by which Leblanc developed sodium carbonate is not known, nor is the exact date. Most likely the method was developed in 1789 after several months of work in the laboratory. After numerous attempts and partial failures, Leblanc eventually succeeded in isolating soda crystals by fusing sulfate, coal, and limestone. In its final incarnation, the method, which became known as the Leblanc process, produced sodium carbonate by first exposing sea salt to sulfuric acid, and then converting the product to soda by calcinating (heating at a high temperature) with limestone and charcoal.

Once the process was established, Leblanc turned his attention to producing soda. He and Dize went to London, where the Duke had been sent as a result of rising political tensions, to discuss the necessary steps. An agreement reached on March 27, 1790 among Leblanc, Dize, and Henri Shee, the Duke's steward, stipulated that Leblanc submit a complete description of the process, which would be certified by Darcet. Dize also submitted his invention of a method for manufacturing sal ammoniac, a complementary process to the production of soda. In return Leblanc and Dize were to receive 200,000 livres to pursue the development of a profitable business of soda production.

In 1791 Leblanc applied for a patent. According to Ralph E. Oesper in the Journal of Chemical Education, a board of examiners reported: "Having carefully examined the method employed by said M. Leblanc for producing soda by the large-scale decomposition of sea salt, we acknowledge that the invention is new and very superior to all that up to now have come to our knowledge as regards to economy, speed and certainty of the method as well as regards to the abundance and purity of the products. We believe that the discovery of M. Leblanc for political and economic reasons merits the encouragement of the French nation, and that the secret of his discovery should be well guarded." Leblanc was granted a secret patent on September 25, 1791, which gave him the sole right to the process for the next 15 years.

Soda Plant at St. Denis

A manufacturing plant was built in St. Denis, a small village located four miles outside of Paris, and production began. With a production rate of between 500 and 600 pounds of soda every day, the soda works had sales totaling 420,000 livres by the spring of 1794. However, the unstable political times brought devastating changes to Leblanc's operation. First, there was a critical shortage of potash (previously the primary source of soda), because it was needed to produce gunpowder, so the French government instructed all soda manufacturers to disclose plant production levels, processes, and sales. Leblanc was ordered to reveal the secrets of his invention. Second, Leblanc was further hampered by the arrest of the Duke, known during the Revolution as Philippe Egalite, and his subsequent beheading on November 6, 1793. The Revolutionary government confiscated all his property, including his interest in the soda plant. In effect, the French government became the chief shareholder of the business.

In the chaos of the revolution, the government suspended production at Leblanc's plant. Even though a review committee highly recommended the operation and commended Leblanc and Dize for their patriotism for revealing the secrets of the process, the French government established soda production at other locations, leaving Leblanc's plant closed. Rather than being allowed to provide his country with soda, Leblanc was ordered to leave the premises, including the house on the factory grounds in which he lived with his wife and children. He received no financial reward for his chemical contribution, nor for his interest in the soda plant. Just months before, Leblanc stood at the threshold of financial success; suddenly he was thrown into poverty.

The Revolution and Aftermath

Leblanc held several government positions after the soda operation was shut down. Beginning in 1792, he served as the administrator to the Department of the Seine for five consecutive terms, but he received no salary for his work. In January 1794 he secured a salaried position as the commissioner of powder and saltpeter, but the department was dissolved within six months, along with Leblanc's job. In February 1794 he was appointed to the temporary Commission of the Arts, a branch of the Committee of Public Instruction. He was responsible, again without remuneration, for taking an inventory of the contents of properties confiscated by the government, including those facilities left vacant because their owners had been guillotined.

In June 1795, as the Revolution was winding down and France was working to restore normalcy, Leblanc was appointed by the Committee on Public Safety to investigate the steps necessary to rebuild the mining industry. After sending back numerous papers and information from the mining regions, Leblanc was named director of a copper and alum mining operation. Although he was supposed to receive a salary and reimbursement for expenses, he never did. After one year, he returned to Paris in desperate financial straits.

Constantly attentive to chemical processes that could be used in industry, Leblanc began researching the possible use of the ammonia that is released when organic matter is subjected to heat. In time, Leblanc developed the use of animal waste to create ammonia, which in turn provided a useful fertilizer. After developing a small-scale mechanism that effectively produced ammonia from animal waste, Leblanc petitioned the government for a grant to establish a commercial plant. He also requested an exclusive patent and the sole rights to certain waste facilities. Although none of his requests were honored and his efforts to establish a plant failed, he can be credited with important developments in the study of fertilizers.

Leblanc's troubles continued. He could not find adequate employment. Considering himself to be academically inadequate, he declined a faculty position offered to him by the Ecole Centale in Alby in 1796. The following year he secured a place on the Council of Conservation, but before his nomination was acted upon, the minister of interior was replaced, and the new director made different appointments. In 1798 Leblanc won an election for the office of second deputy of St. Denis, but the election was contested and the seat was awarded to his opponent. His struggles were exacerbated by a family tragedy: his 16-year-old daughter became suddenly paralyzed and died six months later.

Failure and Depression

LeBlanc still hoped someday to reopen his soda plant or at least to be compensated for his discovery and investment. The Department of Public Safety finally awarded him 3,000 francs as payment for past services, but Leblanc received only 60 francs. By April 1801 Leblanc had enlisted enough support to persuade the French government under Napoleon to return the factory at St. Denis to him and his partners. Because Shee and Dize were otherwise occupied, Leblanc became the director of the whole operation. Despite his best efforts to revive the factory, Leblanc never reestablished a profitable business. The years of idleness had left the machinery in poor condition, and much of the necessary equipment had been confiscated and removed. Also, because Leblanc's process had become public knowledge, others had opened competing plants.

For several years Leblanc worked diligently to secure funds to revive his operation. Finally in November 1804, arbitrators determined LeBlanc was due payment of 52,473 francs--about $10,000--from the government. It was far less than he had hoped, and no money was ever paid. Leblanc fell into deep depression. He became withdrawn and morose, and his health deteriorated. On January 16, 1806, he committed suicide in his study by putting a bullet in his head.

Later, Dize, who took the soda plant from Leblanc's family in payment for a debt owed him by Leblanc, made claims that he was the mastermind of the soda process. However, historians agree that Dize, a trained chemist who believed himself a superior scientist to Leblanc, was overstating his role in the development of the process, and that Leblanc should get the most credit for the first efficient, economical method of producing soda.

Further Reading

• Asimov, Isaac, Asimov's Biographical Encyclopedia of Science and Technology, Doubleday, 1964.
• A Biographical Dictionary of Scientists, Third edition, edited by Trevor I. Williams, Adam and Charles Black, 1982.
• The Cambridge Biographical Encyclopedia, 2nd edition, edited by David Crystal, Cambridge University Press, 1998.
• Daintith, John; Mitchell, Sarah, and Tootill, Elizabeth, A Biographical Encyclopedia of Scientists, Volume 2, Facts on File, 1981.
• Dictionary of Scientific Biography, Volume 8, edited by Charles Coulston Gillispie, Charles Scribner's Sons, 1973.
• Journal of Chemical Education, December 1942; January 1943.
• "Leblanc, Nicolas," World of Invention, http://www.galenet.com (February 5, 2001).
• "Nicolas Leblanc," Merriam-Webster's Biographical Dictionary, http://www.galenet.com (February 5, 2001).