Benutzer:Miskal/Triethylmethylammonium trichloride

Strukturformel
Allgemeines
Name	triethylmethylammonium trichloride
Summenformel	C7H18Cl3N
Externe Identifikatoren/Datenbanken
CAS-Nummer 2460902-02-5
Eigenschaften
Molare Masse	222.58 g/mol
Aggregatzustand	liquid
Sicherheitshinweise
GHS-Gefahrstoffkennzeichnung H- und P-Sätze H: EUH: P:
Soweit möglich und gebräuchlich, werden SI-Einheiten verwendet. Wenn nicht anders vermerkt, gelten die angegebenen Daten bei Standardbedingungen (0 °C, 1000 hPa).

Triethylmethylammonium trichloride is an ionic liquid consisting of an unsymmetric triethylmethylammonium cation and a trichloride anion.

Preparation

Triethylmethylammonium trichloride is prepared by the reaction of triethylmethylammonium chloride and elemental chlorine gas providing triethylmethylammonium trichloride as an yellow ionic liquid at room temperature.

${\ce {[NEt3Me]Cl + Cl2 -> [NEt3Me][Cl3]}}$

Structure and Chemical Bonding

According to the halogen bonding concept, the trichloride anion can be described as an donor-acceptor complex consisting of a chloride anion (the halogen donor) and dichlorine molecule (the halogen acceptor). By donation of electron density of the chloride anion into the axial σ-hole of the dichlorine molecule lying along the Cl-Cl bonding axis. In this way, the trichloride anion ([Cl-Cl-Cl]^-) is formed which theoretically adopts a linear geometry with Cl-Cl bonds of equal length. However, the real structure of the trichloride anion is typically slightly different due to interaction of the trichloride anion with cations or anisotropic effects in the solid state.

A more precise definition of triethylmethylammonium trichloride is given by the sum formula [NEt₃Me][Cl(Cl₂)_n] where n is the number of equivalents of dichlorine that are bonded. By addition of elemental chlorine to [NEt₃Me]Cl (n = 0), the value of n increases consistently forming the trichloride [NEt₃Me][Cl₃] (n = 1), the pentabromide [NEt₃Me][Cl₅] (n = 2) and, at higher chlorine loadings, higher polychlorides. For values of n < 0.8 [NEt₃Me][Cl(Cl₂)_n] is a yellow solid, while for n > 0.8 [NEt₃Me][Cl(Cl₂)_n] exists as an ionic liquid at room temperature.

Applications

Triethylmethylammonium trichloride shows a similar reactivity like tetraethylammonium trichloride or elemental chlorine but is easier to handle then chlorine gas as ist is a liquid at room temperature. For instance, alkenes are chlorinated with triethylmethylammonium trichloride providing the corresponding vicinal 1,2-dichloroalkanes. Recently, the reaction of triethylmethylammonium trichloride with carbon monoxide to phosgene was described. In this reaction, carbon monoxide is oxidized at room temperature and in the dark, while thew reaction of chlorine gas and carbon monoxide requires further activation by sunlight (see phosgene). Alternatively, the reaction can be performed utilizing catalytically amounts of [NEt₃Me]Cl in the presence of elemental chlorine forming presumably the catalytically active species [NEt₃Me][Cl₃] which reacts with carbon monoxide to phosgene while forming [NEt₃Me]Cl.

${\ce {[NEt3Me][Cl3] + CO -> COCl2 + [NEt3Me]Cl}}$