LeBlanc method

In 1864 Ernest Solvay, a Belgian chemist, invented his ammonia-soda process. A few years later the soda ash price was reduced one third. The Solvay process had completely replaced the LeBlanc method by 1915. The Solvay method is still very popular worldwide. However, in this country large deposits of natural trona ore were found in the 1940s in Green River, Wyoming. In the last few years there has been a tremendous conversion from synthetic to natural soda ash. The first and last Solvay plant in the U.S. closed in 1986 (a large Allied Chemical plant in Solvay, NY). Trona ore is found about 500 m below the surface. It is called sodium sesquicarbonate... 

LeBlancs method uses sulfuric acid and common salt to initially produce sodium sulfate, Na2S04. Sodium sulfate is then reacted with charcoal and limestone to produce sodium carbonate and calcium sulfide ... 

Le Bas method Leblanc process Lecigran Leciprime Lecithin... 

Because calcium sulfide contained in the black ash had a highly unpleasant odor, methods were developed to remove the odor by recovering the sulfur, therein providing at least part of the raw-material for the sulfuric acid required in the first part of the process. Thus, the Leblanc prtKcss demonstrated, at the very beginning, the typical ability of the chemical industry to develop new processes and new products, and often in so doing to turn a liability into an asset. 

The classic salt-cake method was introduced with the Leblanc process towards the end of the eighteenth century and is still used to produce HCl where rock-salt mineral is cheaply available (as in the UK Cheshire deposits). The process is endothermic and takes place in two stages ... 

J.L. Leblanc and B. Stragliati, An extraction kinetics method to study the morphology of carbon black filled mbber compounds, J. Appl. Polym. Sci., 63, 959-970, 1997. 

Sadly one of the by-products from his first step was the powerfully corrosive hydrochloric acid, a potentially serious pollutant. But Leblanc may have been so excited at making sodium carbonate that he hardly noticed. He had found a way to synthesize a purer and thus more efficient substitute for the alkali traditionally extracted from plant ashes. When perfected, his method would make stronger, more consistent soda with far more alkali than the best soda made from plants. He must have felt utterly elated. He was a patriot about to save French industry and win a fortune, 12,000 gold coins. 

After Orleans execution in November 1793, his vast properties became state property and Leblanc s factory was seized. Three months later, Leblanc faced even more distressing news. With war threatening, the Committee of Public Safety called for patent holders of soda processes to publish their methods A true republican does not hesitate to relinquish the ownership of even the fruits of his mind when he hears the voice of his... 

Lamentably, Leblanc s method produced as much pollution as soda and devastated entire communities. For each ton of washing soda made, three-quarters of a ton of intensely acidic hydrogen chloride gas spewed into the air. Raining down as hydrochloric acid, it turned trees and hedges into gaunt skeletons and poisoned farmland. Tens of thousands of tons of sulfur compounds were piled around the factories. As hydrochloric acid poured into waterways, it combined with the sulfur to make hydrogen sulfide gas, spreading a rotten egg smell for miles around. 

Charles C. Gillispie. The Discovery of the Leblanc Process. Isis. 48 (June 1957) 152-170. This is the antidote to Anastasi s sentimentalism and the source for Leblanc s method being only one of several unsuccessful factory sympathy of revolutionary government process unprofitable if salt taxed tiresome personality French patents demi-monde and hero in 1860s. 

The process is operated at 80 to 90°C with a slight excess of the calcium hydroxide. This was the only method used for making sodium hydroxide after the invention of the Leblanc process, and before the introduction of the Castner-Kellner process around 1890. The process is still used when the demands for chlorine and sodium hydroxide from the Castner-... 

LeBlanc s method were made by several other chemists, and he never received the reward. LeBlanc, disheartened and destitute, committed suicide in 1806. 

The LeBlanc process was the principal method of producing soda ash until 1860 when the Belgian Ernest Solvay (1838-1922) developed the process that bears his name. The Solvay process, sometimes called the ammonia method of soda production, utilized ammonia, NH3, carbon dioxide, and salt to produce sodium bicarbonate (baking soda), NaHCOj. Sodium bicarbonate was then heated to give soda ash. The series of reactions representing the Solvay process are... 

During the beginning of the nineteenth century, the alkali and acid industries provided the model for other chemical industries. One characteristic of the chemical industry is that development in one area often stimulates development in another area. For example, the lead-chamber method produced enough sulfuric acid to make the acid practical for use in the LeBlanc process. Similarly, the Solvay process used ammonia produced when coke was made for steel production. Certain chemical industries were perceived by royalty and national leaders as critical to their nation s welfare. One of these was the manufacture of gunpowder, also known as blackpowder. Gunpowder is a mixture of approximately... 

Hydrochloric acid is used in numerous applications, but it is generally obtained indirectly as a by-product in other chemical processes. The first large-scale production of hydrochloric acid resulted from the mass production of alkalis such as sodium carbonate (Na C ) and potassium carbonate (potash, K2C03). The depletion of European forests and international disputes made the availability of alkali salts increasingly uncertain during the latter part of the 18th century. This prompted the French Academy of Science to offer a reward to anyone who could find a method to produce soda ash from common salt (NaCl). Nicholas LeBlanc (1743—1806) was credited with solving the problem. LeBlanc proposed a procedure in 1783 and a plant based on LeBlanc s method was opened in 1791. LeBlanc s method uses sulfuric acid and common salt... 

Hence, although the hydroxide can be made by the action of water on the oxide, it is far more economical to employ a method of preparation based on that described by Albertus Magnus. The chloride is first converted into carbonate by Leblanc s or Solvay s process, and the carbonate is subsequently converted into the hydroxide by causticization with lime. If the alkali chloride could be transformed directly into the hydroxide, without the intermediate formation of the carbonate, by a cheap enough process, the waste of industrial energy, so to speak, involved in this roundabout procedure would be avoided. Numerous patents 7 have been obtained for decomposing common salt by steam or superheated steam, but without any useful result. 

For some other methods, see Wagenknecht J. Org. Chem. 1972,37. 1513 Smith Smith J. Chem. Soc., Chem. Common. 1975, 459 Leblanc Moise Tirouflet 7. Organomel. Chem. 1985, 292, 225 Corriu Lanneau Pcrrot Tetrahedron Lett. 1988, 29, 1271. For a list of reagents, with references, see Ref. 508. pp. 620-621. 

Tho entire loss of all the sulphur consumed as sulphuric add in Leblanc s method of converting common salt into carbonate of soda, is justly considered a great objection to that process. Still, although numerous suggestions have been mado, none of tho new processes have succocdod so well as to supersede Leblanc s method and tho Editor is of opinion that it never will be supplanted. At tho same time somo of tho plans recommended are so interesting in a purely theoretical point of view, that the Editor would scarcely be justified in omitting all notice of them. 

Leblanc, C.J., W.M. Stallard, P.G. Green, and E.D. Schroeder. 2003. Passive sampling screening method using thin-layer chromatography plates. Environ. Sci. Technol. 37 3966-3971. 

Bradbury, L.E., LeBlanc, J.F. and McCarthy, D.B. (2004) ProteinChip array-based amyloid beta assays. Methods Mol. Biol. 264, 245-257. 

The origins of the chemical industry can be traced to the Industrial Revolution. Sulfuric acid and sodium carbonate were among the first industrial chemicals. Oil of vitriol (as the former was known) played an important role in the manipulation of metals, but its production on an industrial scale required the development of materials that would resist attack. Sodium carbonate was obtained in its anhydrous form, soda ash, from vegetable material until the quantities produced could no longer meet the rapidly expanding needs of manufacturers of glass, soap, and textiles. This led the Royal Academy of Sciences of Paris, in 1775, to establish a contest for the discovery of a process based on an abundant raw material, sodium chloride, and to Nicolas Leblanc s method for the preparation of soda by converting salt into sulfate... 

Chlorine was at first produced commercially by the reaction of sulphuric acid, sodium chloride and black oxide of manganese. Later on when Leblanc s method for the production of soda ash was developed, in the first stage of which hydrogen chloride is a by-product, hydrochloric acid was used instead of sodium chloride and sulphuric acid. This process was carried out in stoneware or porcelain vats which were steam heated from the outside. Reaction between manganese dioxide and hydrochloric acid proceeds in two stages ... 

Sodium ferric sulphide occurs in the c< black ash 55 liquors formed in the Leblanc Soda Process,2 and a convenient wet method of producing it in the laboratory consists in adding a solution of a ferric salt to excess of sodium sulphide solution. It also results when excess of sodium polysulphide acts on a solution of a ferrous salt.3... 

---