Editing Chemical reaction (section)

==History==
[[File:David - Portrait of Monsieur Lavoisier (cropped).jpg|thumb|[[Antoine Lavoisier]] developed the theory of combustion as a chemical reaction with oxygen.]]

Chemical reactions such as combustion in fire, [[fermentation (biochemistry)|fermentation]] and the reduction of ores to metals were known since antiquity. Initial theories of transformation of materials were developed by Greek philosophers, such as the [[Classical element|Four-Element Theory]] of [[Empedocles]] stating that any substance is composed of the four basic elements – fire, water, air and earth. In the [[Middle Ages]], chemical transformations were studied by [[alchemist]]s. They attempted, in particular, to convert [[lead]] into [[gold]], for which purpose they used reactions of lead and lead-copper alloys with [[sulfur]].<ref>{{Cite journal | doi = 10.1002/ciuz.19730070604| title = Neuere Interpretationsmöglichkeiten der Alchemie| journal = Chemie in unserer Zeit| volume = 7| issue = 6| pages = 177–181| year = 1973| last1 = Weyer | first1 = J. }}</ref>

The artificial production of chemical substances already was a central goal for medieval alchemists.<ref>See {{Cite book|last=Newman|first=William R.|author-link=William R. Newman|year=2004|title=Promethean Ambitions: Alchemy and the Quest to Perfect Nature|location=Chicago|publisher=University of Chicago Press|isbn=9780226575247}}</ref> Examples include the synthesis of [[ammonium chloride]] from [[Organic compound|organic substances]] as described in the works (c. 850–950) attributed to [[Jabir ibn Hayyan|Jābir ibn Ḥayyān]],<ref>{{Cite book|last=Kraus|first=Paul|author-link=Paul Kraus (Arabist)|year=1942–1943|title=Jâbir ibn Hayyân: Contribution à l'histoire des idées scientifiques dans l'Islam. I. Le corpus des écrits jâbiriens. II. Jâbir et la science grecque|publisher=[[Institut Français d'Archéologie Orientale]]|location=Cairo|oclc=468740510|isbn=9783487091150}}, vol. II, pp. 41–42.</ref> or the production of [[mineral acids]] such as [[sulfuric acid|sulfuric]] and [[nitric acid]]s by later alchemists, starting from c. 1300.<ref>{{Cite journal|last1=Karpenko|first1=Vladimír|last2=Norris|first2=John A.|year=2002|title=Vitriol in the History of Chemistry|journal=Chemické listy|volume=96|issue=12|pages=997–1005|url=http://www.chemicke-listy.cz/ojs3/index.php/chemicke-listy/article/view/2266}}</ref> The production of mineral acids involved the heating of sulfate and nitrate minerals such as [[copper sulfate]], [[alum]] and [[Potassium nitrate|saltpeter]]. In the 17th century, [[Johann Rudolph Glauber]] produced [[hydrochloric acid]] and [[sodium sulfate]] by reacting sulfuric acid and [[sodium chloride]]. With the development of the [[lead chamber process]] in 1746 and the [[Leblanc process]], allowing large-scale production of sulfuric acid and [[sodium carbonate]], respectively, chemical reactions became implemented into the industry. Further optimization of sulfuric acid technology resulted in the [[contact process]] in the 1880s,<ref>{{cite book | author = Friedman, Leonard J. | author2 = Friedman, Samantha J. | url = http://www.aiche-cf.org/Clearwater/2008/Paper2/8.2.7.pdf | title = The History of the Contact Sulfuric Acid Process | year = 2008 | publisher = Acid Engineering & Consulting, Inc. | location = Boca Raton, Florida}}</ref> and the [[Haber process]] was developed in 1909–1910 for [[ammonia]] synthesis.<ref>{{cite encyclopedia | editor = Lesch, John E. | url = https://books.google.com/books?id=VJIztvolC8cC&pg=PA170 | title = The German Chemical Industry in the Twentieth Century | author = Stranges, Anthony N. | contribution = Germany's synthetic fuel industry, 1935–1940 | publisher = [[Kluwer Academic Publishers]] | year = 2000 | isbn = 978-0-7923-6487-0 | page = 170}}</ref>

From the 16th century, researchers including [[Jan Baptist van Helmont]], [[Robert Boyle]], and [[Isaac Newton]] tried to establish theories of experimentally observed chemical transformations. The [[phlogiston theory]] was proposed in 1667 by [[J. J. Becher|Johann Joachim Becher]]. It postulated the existence of a fire-like element called "phlogiston", which was contained within combustible bodies and released during [[combustion]]. This proved to be false in 1785 by [[Antoine Lavoisier]] who found the correct explanation of the combustion as a reaction with oxygen from the air.<ref>[[#Brock|Brock]], pp. 34–55</ref>

[[Joseph Louis Gay-Lussac]] recognized in 1808 that gases always react in a certain relationship with each other. Based on this idea and the atomic theory of [[John Dalton]], [[Joseph Proust]] had developed the [[law of definite proportions]], which later resulted in the concepts of [[stoichiometry]] and [[chemical equation]]s.<ref>[[#Brock|Brock]], pp. 104–107</ref>

Regarding the [[organic chemistry]], it was long believed that compounds obtained from living organisms were too complex to be obtained [[Chemical synthesis|synthetically]]. According to the concept of [[vitalism]], organic matter was endowed with a "vital force" and distinguished from inorganic materials. This separation was ended however by the synthesis of [[urea]] from inorganic precursors by [[Friedrich Wöhler]] in 1828. Other chemists who brought major contributions to organic chemistry include [[Alexander William Williamson]] with his [[Williamson ether synthesis|synthesis]] of [[ether]]s and [[Christopher Kelk Ingold]], who, among many discoveries, established the mechanisms of [[substitution reaction]]s.