Hydrochloric Acid - History

History

Aqua regia, a mixture consisting of hydrochloric acid and nitric acid, prepared by dissolving sal ammoniac in nitric acid, was described in the works of Pseudo-Geber, the 13th-century European alchemist. Other references suggest that the first mention of aqua regia is in Byzantine manuscripts dating to the end of the thirteenth century.

Free hydrochloric acid was first formally described in the 16th century by Libavius, who prepared it by heating salt in clay crucibles. Other authors claim that pure hydrochloric acid was first discovered by the German benedictine monk Basil Valentine in the 15th century, by heating common salt and green vitriol, whereas others claim that there is no clear reference to the preparation of pure hydrochloric acid until the end of the sixteenth century.

In the seventeenth century, Johann Rudolf Glauber from Karlstadt am Main, Germany used sodium chloride salt and sulfuric acid for the preparation of sodium sulfate in the Mannheim process, releasing hydrogen chloride gas. Joseph Priestley of Leeds, England prepared pure hydrogen chloride in 1772, and in 1818 Humphry Davy of Penzance, England proved that the chemical composition included hydrogen and chlorine.

During the Industrial Revolution in Europe, demand for alkaline substances increased. A new industrial process by Nicolas Leblanc (Issoundun, France) enabled cheap large-scale production of sodium carbonate (soda ash). In this Leblanc process, common salt is converted to soda ash, using sulfuric acid, limestone, and coal, releasing hydrogen chloride as a by-product. Until the British Alkali Act 1863 and similar legislation in other countries, the excess HCl was vented to air. After the passage of the act, soda ash producers were obliged to absorb the waste gas in water, producing hydrochloric acid on an industrial scale.

In the twentieth century, the Leblanc process was effectively replaced by the Solvay process without a hydrochloric acid by-product. Since hydrochloric acid was already fully settled as an important chemical in numerous applications, the commercial interest initiated other production methods, some of which are still used today. After the year 2000, hydrochloric acid is mostly made by absorbing by-product hydrogen chloride from industrial organic compounds production.

Since 1988, hydrochloric acid has been listed as a Table II precursor under the 1988 United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances because of its use in the production of heroin, cocaine, and methamphetamine.