Deep eutectic solvent

As Stark eutectic solvent (DES of English Deep Eutectic Solvents) are multicomponent eutectic molten salt refers to the melting point as the lies of ionic liquids near or below room temperature. The term is misleading when no special mechanism is present, which results in a particularly strong reduction of the melting point in comparison to other eutectics.

Known solvent based on a eutectic mixture of quaternary ammonium compounds with Wasserstoffbrückenbindungsdonoren (eg amines), and carboxylic acids. In 2003, the first time the phenomenon of a strong eutectic mixture of choline chloride (2- hydroxy-N, N, N- trimethyl- ethanaminiumchlorid ) and urea was described in the molar ratio 1:2. The melting point of this eutectic mixture is thick at 12 ° C, while that of choline chloride 302 ° C and 133 ° C is of urea. ,

OF were examined with respect to their applicability in a laboratory scale and for the industry. In this case, it was found that the eutectic described (see above) various metal salts such as lithium chloride ( solubility of 2.5 mol · L-1 ) and copper ( II) oxide (solubility 0.12 mol · L-1 ) triggers. For an application in metal cleaning processes ( electroplating ) seems possible. DES can be employed as electric polishes, since they are electrically conductive. In the field of organic chemistry can be used as solvent, for example of benzoic acid (solubility 0.82 mol · L-1 ), or even for cellulose.

In comparison to classical solvents OF are not volatile, so have no vapor pressure, and are therefore very difficult to ignite ( flammability ). More choline chloride -based DES are formed (-35 ° C) with malonic acid (mp 0 ° C ), phenol (-40 ° C) or glycerol.

Compared to ionic liquids, which are just as DES composed of ions and therefore have similar properties, DES are cheaper to produce, since they are merely mixtures of common laboratory chemicals. Other advantages compared to conventional ILs are the fluorine freedom and the good, or well-known biodegradability.