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== Special areas of volatility research and technology development ==


=== Odors from volatile substances acting as social behavioral signals or codes ===
The ability to recognize individuals or their genetic relatedness has an important role in the social behavior of mammals. Mammalian social systems rely on signals passed between individuals that provide information about sex, reproductive status, individual identity, ownership, competitive ability and health status. Many of these signals take the form of volatile substances that are used to signal at a distance and are sensed by the mammalian olfactory systems. Despite the complexities of all mammalian societies, there are instances where volatile single molecules can act as classical pheromones attracting interest and approach behavior. The behavior of most, if not all, insect species are also highly dependent upon the olfactory perception of odors from volatile substances.
Comprehensive reviews of the research work in this area are available on the Internet.<ref>{{cite journal|author=Peter Brennan and Keith Kendrick |title=Mammalian social odours: attraction and individual recognition|journal=Phil. Trans. R. Soc. B|volume=261|issue=1476| pages=2061-2078|date=2006|id=|url=http://rstb.royalsocietypublishing.org/content/361/1476/2061.full.pdf+html?sid=30ec0070-c014-4a8e-bbb5-995806ad264e}}</ref><ref>{{cite journal|author=M. de Bruyne and T. C. Baker|title=Odor Detection in Insects: Volatile Codes| journal=J. Chem. Eco. |volume=34 | issue=| pages=882-897
|date=2008|id=|url=http://ento.psu.edu/publications/151deBruyne-BakerJCE2008.pdf}}</ref>
=== Ionic liquids ===
[[Ionic liquid]]s consist exclusively, or almost exclusively, of [[ion]]s and  and were traditionally known in the past as ''[[Salt (chemistry)|molten salts]]''.  Over the past twenty years or so, they have become to be defined as [[Salt (chemistry)|salts]] having [[melting point]]s below the arbitrarily chosen temperature of 100 °[[Celsius (unit)|C]]. Most ionic liquids consist of organic [[cation]]s and either organic or inorganic [[anion]]s. Binary mixtures of an organic salt and an inorganic salt are also ionic liquids. Aqueous solutions of salts are not classified as ionic liquids because they do not consist exclusively of ions.<ref name=Freemantle>{{cite book|author=Michael Freemantle|title=An Introduction to Ionic Liquids|edition=1st Edition|publisher=Royal Society of Chemistry|year=2009|id=ISBN 1-84755-161-0}}</ref>
The origins of ionic liquid chemistry began with the work of [[Charles Friedel]] and [[James F. Crafts]] in 1877 and [[Siegmund Gabrie]]l in 1888. The term "ionic liquids" was first coined in 1961 by [[H. Bloom]] at a [[Faraday Society]] discussion.<ref name=Freemantle/><ref>{{cite journal | author = Charles Friedel and James M. Crafts | title = Sur une nouvelle méthode générale de synthèse d'hydrocarbures, d'acétones, etc. | journal = Compt. Rend. | year = 1877 | volume = 84 | pages = pages 1392 and 1450 | url = http://gallica.bnf.fr/ark:/12148/bpt6k30410/f1386.table}}</ref><ref>{{cite journal| author=Siegmund Gabriel and J. Weiner| title=Ueber einige Abkömmlinge des Propylamins | journal=Berichte der Deutschen chemischen Gesellschaft | year=1887 |volume= 21 | issue=2| pages= pages 2669 - 2674 |url=http://onlinelibrary.wiley.com/doi/10.1002/cber.18880210288/abstract}}</ref><ref>{{cite journal|  author=H. Bloom | title=Eleventh Spiers Memorial Lecture: Structural models for molten salts and their mixtures | Discuss. Faraday. Soc. |year=1961 | volume=32 | issue= |pages= pages 7-13 |url=http://www.rsc.org/publishing/journals/DF/article.asp?doi=DF9613200007}}</ref> Over the years since then, various names and acronyms have have been used in the scientific literature for organic salts with low melting points, including ionic liquid (IL), room temperature ionic liquid (RTIL), ambient temperature  ionic liquid, non-aqueous ionic liquid (NAIL) and molten organic salt.
Ionic liquids have attracted the attention of chemists for many reasons:<ref name=Freemantle/>
*The potential for research on ionic liquids is very great. More than 1500 ionic liquids have already been reported in the scientific literature and, in theory, a million or so simple ionic liquids are possible. An almost limitless number of ionic liquids are theoretically possible by mixing two or more simple ionic liquids.
*Unlike organic molecular solvents, ionic liquids have negligible vapor pressures and therefore do not undergo evaporation under normal ambient conditions. For that reason, they are looked upon as "environmentally friendly" and "green" replacements for VOCs.<ref name=Pham>{{cite journal| author=Thi Phuong Thuy Pham, Chul-Woong Cho and Yeoung-Sang Yun | title=Environmental fate and toxicity of ionic liquids: A review | journal= Water Research | volume=34 | issue=2 |pages=pages 352-372 |date= 2010 |id= |url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-4X9FGNX-2&_user=10&_coverDate=01%2F31%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1480561326&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4c401ae780982014bdbc335f0af26e37&searchtype=a |}}</ref>
*Ionic liquids are generally non-flammable and many remain thermally stable at temperatures higher than conventional organic molecular solvents.
*Ionic liquids can be used as [[chemical reaction]] media and/or [[Catalysis|catalysts]] for a wide variety of chemical reactions.
*The physical, chemical and biochemical properties of ionic liquids can be "tailored" or "designed" by:
**Switching anions or cations.
**By mixing two or more  simple ionic liquids.
**By designing special functionalities into the anions and/or cations.
*Ionic liquids have  many applications in [[electrochemistry]], [[biochemistry]] and other branches of chemistry.
A comprehensive review of the environmental fate and toxicity  of ionic liquids concluded that their low volatility does not eliminate potential environmental hazards and may have serious adverse consequences for aquatic and terrestrial ecosystems. That review recommends more research and more studies be conducted into the environmental aspects of ionic liquids.<ref name=Pham/>
==References==
{{reflist}}

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