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|Section2= |Section7= |Section8= }} Picric acid is the chemical compound formally called 2,4,6-trinitrophenol (TNP). This yellow crystalline solid is one of the most acidic phenols and is vinylogous to nitric acid. Like other highly nitrated compounds such as TNT, picric acid is an explosive. Its name comes from Greek πικρος (''pik' ros''), meaning "bitter", reflecting its bitter taste. Its primary use, now outdated, is as an explosive. It has also been used in medicine (antiseptic, burn treatments), dyes, and as a chemistry agent. == History == Picric acid was probably first mentioned in the alchemical writings of Johann Rudolf Glauber in 1742. Initially, it was made by nitrating substances such as animal horn, silk, indigo, and natural resin, the synthesis from indigo first being performed by Peter Woulfe in 1771.〔Peter Woulfe (1771) ("Experiments to shew the nature of aurum mosaicum," ) ''Philosophical Transactions of the Royal Society of London'', 61 : 114-130. See pages 127-130: "A method of dying wool and silk, of a yellow colour, with indigo; and also with several other blue and red colouring substances." and "Receipt for making the yellow dye." — where Woulfe treats indigo with nitric acid ("acid of nitre").〕 Its synthesis from phenol, and the correct determination of its formula, were successfully accomplished in 1841.〔Auguste Laurent (1841) ("Sur le phényle et ses dérivés" ) (On phenol and its derivatives), ''Annales de Chimie et de Physique'', series 3, 3 : 195-228 ; see especially pages 221-228.〕 Not until 1830 did chemists think to use picric acid as an explosive. Before then, chemists assumed that only the salts of picric acid were explosive, not the acid itself. In 1871 Hermann Sprengel proved it could be detonated〔Note: * In March 1871, Sprengel detonated picric acid at the gunpowder works of John Hall & Sons in Faversham in Kent, England. * Sprengel filed patents in Britain for "safety explosives" (i.e., stable explosives) on April 6, 1871 (no. 921) and on October 5, 1871 (no. 2642); in the latter patent, Sprengel proposed using picric acid dissolved in nitric acid as an explosive. * Hermann Sprengel (1873) "On a new class of explosives which are non-explosive during their manufacture, storage, and transport," ''Journal of the Chemical Society'', 26 : 796-808. * Hermann Sprengel, (''The Discovery of Picric Acid (Melinite, Lyddite) "As a Powerful Explosive"'' ... ), 2nd ed. (London, England: Eyre & Spottiswoode, 1903). This pamphlet is a collection of (splenetic) letters in which Sprengel defends his priority in the use of picric acid as a high explosive.〕 and most military powers used picric acid as their main high explosive material. Picric acid is also used in the analytical chemistry of metals, ores, and minerals. Picric acid was the first high explosive nitrated organic compound widely considered suitable to withstand the shock of firing in conventional artillery. Nitroglycerine and guncotton were available earlier but shock sensitivity sometimes caused detonation in the artillery barrel at the time of firing. In 1885, based on research of Hermann Sprengel, French chemist Eugène Turpin patented the use of pressed and cast picric acid in blasting charges and artillery shells. In 1887 the French government adopted a mixture of picric acid and guncotton under the name Melinite. In 1888, Britain started manufacturing a very similar mixture in Lydd, Kent, under the name Lyddite. Japan followed with an "improved" formula known as shimose powder. In 1889, a similar material, a mixture of ammonium cresylate with trinitrocresol, or an ammonium salt of trinitrocresol, started to be manufactured under the name ecrasite in Austria-Hungary. By 1894 Russia was manufacturing artillery shells filled with picric acid. Ammonium picrate (known as Dunnite or explosive D) was used by the United States beginning in 1906. However, shells filled with picric acid become highly unstable if the compound reacts with metal shell or fuze casings to form metal picrates which are more sensitive than the parent phenol. The sensitivity of picric acid was demonstrated in the Halifax Explosion. Picric acid was used in the Battle of Omdurman,〔Brown, G.I. (1998) ''The Big Bang: a History of Explosives'' Sutton Publishing ISBN 0-7509-1878-0 pp.151-163〕 Second Boer War, the Russo-Japanese War,〔(Dunnite Smashes Strongest Armor ), ''The New York Times'', August 18, 1907〕 and World War I.〔Marc Ferro. ''The Great War''. London and New York: Routeladge Classics, p. 98.〕 Germany began filling artillery shells with TNT in 1902. Toluene was less readily available than phenol, and TNT is less powerful than picric acid, but improved safety of munitions manufacturing and storage caused replacement of picric acid by TNT for most military purposes between the World Wars.〔 Efforts to control the availability of phenol, the precursor to picric acid, emphasize its importance in World War I. Germans are reported to have bought US supplies of phenol and converted it to acetylsalicylic acid, i.e., aspirin, to keep it from the Allies. At the time, phenol was obtained from coal as a co-product of coke ovens and the manufacture of gas for gas lighting. Laclede Gas reports being asked to expand production of phenol (and toluene) to support the war effort.〔Beck, Bill (2007) ''Laclede Gas and St. Louis: 150 Years Working Together, 1857-2007'', Laclede Gas Company, ISBN 978-0-9710910-1-6 p. 64〕 Both Monsanto〔Forrestal, Dan J. (1977), ''Faith, Hope & $5000: The Story of Monsanto'', Simon & Schuster, ISBN 0-671-22784-X() p. 24〕 and Dow Chemical〔Brandt, E.N. (1997), ''Growth Company: Dow Chemical's First Century'', Michigan State University, ISBN 0-87013-426-4 p. 77, 97 and 244〕 undertook manufacture of synthetic phenol in 1915. Dow was the leading producer. Dow describes picric acid as “the main battlefield explosive used by the French. Large amounts (phenol ) also went to Japan, where it was made into picric acid sold to the Russians.” 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Picric acid」の詳細全文を読む スポンサード リンク
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