Deep eutectic solvent
2777190
142093907
2007-07-02T21:16:18Z
129.130.42.32
Had the choline chloride:urea ratio as 2:1 instead of 1:2
A '''deep eutectic solvent''' or '''DES''' is a type of [[Ion|ionic]] [[solvent]] with special properties composed of a mixture which forms a [[eutectic]] with a [[melting point]] much lower than either of the individual components. The first generation eutectic solvents were based on mixtures of [[quaternary ammonium]] [[salt]]s with [[hydrogen donor]]s such as [[amine]]s and [[carboxylic acid]]s. The deep eutectic phenomenon was first described in [[2003]] for a 1 to 2 by [[mole (chemistry)|mole]] mixture of [[choline chloride]] (2-hydroxyethyl-trimethylammonium chloride) and [[urea]]. Choline chloride has a melting point of 302 [[°C]] and that of urea is 133 [[°C]]. The eutectic mixture however melts as low as 12 [[°C]].
This DES is able to dissolve many [[metal]] [[salts]] like [[lithium chloride]] ([[solubility]] 2.5 [[mole (unit)|mol]]/[[Litre|L]]) and [[copper(II) oxide]] (solubility 0.12 mol/L). In this capacity these solvents are applied in metal cleaning for [[electroplating]]. Because the solvent is [[conductive]] it also has a potential application in [[electropolishing]]. [[Organic compound]]s such as [[benzoic acid]] (solubility 0.82 mol/L) also have great solubility and this even includes [[cellulose]] (filtration paper!). Compared to ordinary solvents, eutectic solvents also have a very low [[Volatile organic compound|VOC]] and are non-flammable.
Other deep eutectic solvents of choline chloride are formed with [[malonic acid]] at 0 [[°C]], [[phenol]] at -40 [[°C]] and [[glycerol]] at -35 [[°C]].
Compared to [[ionic liquid]]s which share many charactistics but are ionic compounds and not ionic mixtures, deep eutectic solvents are cheaper to make, much less [[toxic]] and sometimes [[biodegradation|biodegradable]].
== External links ==
* Deep eutectics at www.rsc.org [http://www.rsc.org/Education/EiC/issues/2005_Jan/salty.asp Website]
* [http://www.scionix.co.uk/Scionix_brochure.PDF Commercial supplier]
== References ==
# {{Note|1}} ''Novel solvent properties of choline chloride/urea mixtures'' Andrew P. Abbott, Glen Capper, David L. Davies, Raymond K. Rasheed, Vasuki Tambyrajah [[Chemical Communications]], '''2003''', (1), 70 - 71 [http://www.rsc.org/Publishing/Journals/CC/article.asp?doi=b210714g Graphic abstract]
# {{Note|1}} ''Deep Eutectic Solvents Formed between Choline Chloride and Carboxylic Acids: Versatile Alternatives to Ionic Liquids'' Abbott, A. P.; Boothby, D.; Capper, G.; Davies, D. L.; Rasheed, R. K.; [[J. Am. Chem. Soc.]]; '''2004'''; 126(29); 9142-9147. [http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2004/126/i29/abs/ja048266j.html Abstract]
[[category:organic chemistry]]