John Roebuck found a way to produce sulfuric acid in greater quantities and at a lower price than had been possible previously. His lead-chamber process increased the British supply of sulfuric acid, making it possible to develop new applications and to export the substance for sale to foreign markets.

In the mid-eighteenth century, chemistry was beginning to make the transition from alchemical practices to the modern era. The Industrial Revolution Industrial Revolution;England was beginning, and manufacturing Chemicals and manufacturing industries began to require chemicals as raw materials. Sulfuric acid, Acids, industrial perhaps more than any other single chemical, was needed by a variety of industries, yet the supply was limited by inadequate, preindustrial methods of manufacture. Although sulfuric acid had been known for centuries, it had always been prepared in small quantities from metal sulfates. As the demand for the acid increased, it was eventually recognized that plentiful elemental sulfur was a more favorable raw material for sulfuric acid manufacture. Iron sulfide (pyrite) could also be used and was often less expensive than elemental sulfur. [kw]Roebuck Develops the Lead-Chamber Process (1746)
[kw]Process, Roebuck Develops the Lead-Chamber (1746)
[kw]Chamber Process, Roebuck Develops the Lead- (1746)
[kw]Lead-Chamber Process, Roebuck Develops the (1746)
Sulfuric acid
Lead-chamber process[Lead chamber]
[g]England;1746: Roebuck Develops the Lead-Chamber Process[1150]
[c]Chemistry;1746: Roebuck Develops the Lead-Chamber Process[1150]
[c]Science and technology;1746: Roebuck Develops the Lead-Chamber Process[1150]
[c]Manufacturing;1746: Roebuck Develops the Lead-Chamber Process[1150]
Roebuck, John
Garbett, Samuel
Ward, Joshua

Sulfur burns readily in air, releasing sulfur dioxide gas, a noxious chemical. Sulfur dioxide gas, upon further oxidation, becomes sulfur trioxide, which, when combined with water, forms sulfuric acid. Sulfuric acid itself is an oily, corrosive liquid with a high boiling point, and when pure it is nearly twice as dense as water. The conversion of sulfur dioxide to sulfur trioxide requires oxygen and a catalyst. In the eighteenth century, it was known that adding nitre (potassium nitrate) to burning sulfur could catalyze the conversion, but the details of the complex reactions involved were not then appreciated.

Joshua Ward was able to make sulfuric acid as early as 1740 by burning mixtures of sulfur and nitre and combining the resulting gases with water. His efforts were limited, however, by the relatively small and fragile glass vessels he used, and his product was expensive and available in limited quantity. At the same time, there was significant demand for the acid in the textile and metals industries. Ward patented his method in 1749 and produced the acid at Twickenham and Richmond.

Meanwhile, physician John Roebuck had become interested in chemistry during his medical education, and he decided to set up a laboratory in Birmingham with his collaborator Samuel Garbett. They attempted to improve sulfuric acid production techniques. Roebuck realized that lead was resistant to the corrosive properties of moderately concentrated sulfuric acid and designed his process so that the acid was formed in 4-by-6-by-8 foot wooden chambers lined with lead sheets. Using this method, the acid attained a concentration of about 50 percent, and it could be sold for a price about one-fourth that of Ward’s product. Once this process had been demonstrated with the initial lead chambers, the scale of manufacture could be increased by building larger chambers, as well as by employing many chambers simultaneously.

Roebuck and Garbett failed to patent their process in England, and they were prevented from developing it further in Birmingham by Joshua Ward’s patent. In order to continue their work, they moved to Scotland and built a manufacturing plant at Prestonpans, near Edinburgh. From Prestonpans, they had access to the sea for shipping, and they were able to begin exporting sulfuric acid to the Continent around 1750. The demand for their product led them to build 108 chambers at Prestonpans and even more at a second plant at Burntisland with a total volume at the two locations of almost 130,000 cubic feet. In recognition of his achievements in science and technology, Roebuck was made a fellow of the Royal Society Royal Society, England in 1764.

The manufacture and sale of the acid were very profitable, but eventually the secrets of the lead-chamber process became generally known. Lacking patent protection, Roebuck and Garbett faced widespread competition. The French soon learned how to build lead-chamber plants, and by 1786 they were operating four such installations. The first lead-chamber plant in the United States was built in 1793 near Philadelphia, and by 1804 it could produce 250 tons of acid each year. In 1917, this plant was sold to the DuPont Corporation.

The sulfuric acid made available in quantity by Roebuck’s lead-chamber process found many uses in the chemical industry. In the eighteenth century, for example, sulfuric acid began to be used to bleach Bleaching of textiles linen and cotton. Chlorine bleaches were not yet available in quantity. After 1789, with the introduction of the Leblanc process for making sodium carbonate, that industry became a major consumer of sulfuric acid. Sodium carbonate was needed for soap and glass making and had been obtained from wood ashes or other plant sources. The Leblanc process (no longer used) enabled the manufacture of sodium carbonate from readily available salt (sodium chloride) through a series of reactions in which the salt first reacted with sulfuric acid to form sodium sulfate. British production of sodium carbonate reached 70,000 tons per year by 1850.

The lead-chamber process was further developed and improved throughout the nineteenth century. Major improvements included the Gay-Lussac tower (named for its designer, Joseph-Louis Gay-Lussac) and the Glover tower. In the first of these towers, excess oxides of nitrogen are absorbed in sulfuric acid which trickles down over tile fragments against the gas stream. This prevents them from being emitted as pollutants. The acid from the Gay-Lussac tower is then processed in the Glover tower, where it gives up the oxides of nitrogen it has absorbed so that they can be recycled. This process also causes the acid to become more concentrated.

The lead-chamber process was gradually superseded by the contact process, invented in 1831. The contact process avoids the complex chemistry associated with nitrogen oxides altogether. Instead, it achieves the catalytic conversion of sulfur dioxide to sulfur trioxide through the use of a solid catalyst. A platinum catalyst is very effective but expensive. Modern sulfuric acid plants use a contact catalyst consisting of vanadium pentoxide. The emergence of the synthetic dye industry in the 1880’s created a demand for extremely concentrated grades of acid (oleum) that were advantageously made by the contact process. The last lead-chamber installations were taken out of service in the 1970’s.

After 1842, large quantities of sulfuric acid began to be used in the manufacture of phosphate fertilizers. Fertilizers J. B. Lawes (1814-1900) in England used the reaction of sulfuric acid with phosphate minerals, such as coprolite, to make soluble phosphates Phosphates for agricultural use. By the 1860’s, annual production of these fertilizers had reached 150,000 tons in Britain. Not only phosphates but also nitrogen fertilizers were in demand. Ammonia from the distillation of soft coal could be absorbed in sulfuric acid to form ammonium sulfate—a form of nitrogen fertilizer. This use of coal with sulfuric acid expanded alongside the increasing use of coal tar as a source of chemicals for the dye industry. In the twenty-first century, fertilizer manufacturing consumes more sulfuric acid than any other industry.

As the steel and petroleum industries developed, they began to use sulfuric acid as well. Steel plates could be cleaned of surface rust by acid treatment, and sulfuric acid was used in alkylation reactions that produce improved quality motor fuels. In addition, in the eighteenth and nineteenth centuries, several explosives were discovered that were made by nitrating various materials with a mixture of sulfuric and nitric acids. Explosives such as nitrocellulose, nitroglycerin, picric acid, and trinitrotoluene (TNT) are all made by nitration reactions that involve sulfuric acid.

The many uses of sulfuric acid and its enormous production make it arguably the single most significant heavy chemical. Annual U.S. production of the acid exceeds 40 million tons.

• Clow, A., and N. C. Clow. The Chemical Revolution. Freeport, N.Y.: Books for Libraries Press, 1970. A wide-ranging study of the beginnings of the chemical industry, devoting a chapter to vitriol (sulfuric acid) in the Industrial Revolution.
• Dunn, Kevin M. Caveman Chemistry. Parkland, Fla.: Universal, 2003. Chapter 18 contains a simple experiment to demonstrate the lead-chamber process using a 2-liter soda bottle.
• Kent, James A. Riegel’s Handbook of Industrial Chemistry. 7th ed. New York: Van Nostrand Reinhold, 1974. A detailed description of the lead-chamber process in its twentieth century form.
• Kiefer, D. M. “Sulfuric Acid: Pumping up the Volume—Today’s Chemist at Work.” Chemistry Chronicles 10, no. 9 (September, 2001). Traces the adoption of the lead-chamber process in various countries from the late eighteenth to the twentieth century.

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Nicolas Leblanc; John Roebuck. Sulfuric acid
Lead-chamber process[Lead chamber]