Alkyl Ammonium Chloride Salts for Efficient Chlorine Storage at Ambient Conditions

Abstract

Herein, we report the use of alkyl ammonium chloride salts as safe and sustainable chlorine storage media. The most promising candidate, [NEt3Me]­Cl, stores up to 0.79 kg chlorine/kg storage material, is readily prepared, and stable against chlorination for extended times. Chlorine release can be achieved by applying heat or vacuum, or, alternatively, by the addition of water. The combination of these properties emphasizes [NEt3Me]Cl as a suitable storage medium to facilitate the flexibilization of industrial chlorine production. As polychlorides can be used for various chlorination reactions, a combined industrial process is envisaged utilizing [NEt3Me]Cl as the storage medium and the loaded system, [NEt3Me]­[Cl­(Cl2) n ] (n = 1.68), as the reagent for industrial chlorinations.

The Rise of Trichlorides Enabling an Improved Chlorine Technology

“…It is stable over years at room temperature and shows also no decomposition when stored in the sunlight at 50 °C. [21] [NEt 3 Me][Cl 3 ] stores up to 0.79 kg chlorine per kilogram of [NEt 3 Me]Cl, and is comparably cheap as [NEt 3 Me]Cl is industrially prepared from two base chemicals, NEt 3 and MeCl. [21] Notably, [NEt 3 Me][Cl 3 ] has a much lower vapor pressure then elemental chlorine at room temperature.…”

Synthesis of a Hexachloro Sulfate(IV) Dianion Enabled by Polychloride Chemistry

“…The chlorination of small molecules is a topic of major relevance both for industrial and academic research [1] . Very recently, our group in cooperation with Covestro investigated [NEt 3 Me]Cl as a practical chlorine storage medium which forms the corresponding trichloride [NEt 3 Me][Cl 3 ] by addition of chlorine [2] . More importantly, we found that [NEt 3 Me][Cl 3 ] is also a useful chlorinating agent reacting with carbon monoxide to the base chemical phosgene (COCl 2 ).…”

“…[1] Very recently, our group in cooperation with Covestro investigated [NEt 3 Me]Cl as a practical chlorine storage medium which forms the corresponding trichloride [NEt 3 Me][Cl 3 ] by addition of chlorine. [2] More importantly, we found that [NEt 3 Me][Cl 3 ] is also a useful chlorinating agent reacting with carbon monoxide to the base chemical phosgene (COCl 2 ). Interestingly, our studies indicate that the trichloride anion in [NEt 3 Me][Cl 3 ] has a ClÀ Cl bond which is much weaker than in elemental chlorine facilitating the insertion of carbon monoxide into the ClÀ Cl bond of the trichloride.…”

Synthese des Hexachlorosulfat(IV)‐Dianions ermöglicht durch Polychloridchemie

“…Die Chlorierung kleiner Moleküle ist sowohl für die industrielle als auch für die akademische Forschung von großer Bedeutung [1] . Erst kürzlich untersuchte unsere Gruppe in Zusammenarbeit mit Covestro [NEt 3 Me]Cl als praktisches Chlorspeichermedium, das durch Zugabe von Chlor das entsprechende Trichlorid [NEt 3 Me][Cl 3 ] bildet [2] . Hervorzuheben ist, dass [NEt 3 Me][Cl 3 ] auch ein nützliches Chlorierungsmittel ist, welches mit Kohlenmonoxid zu der Basischemikalie Phosgen (COCl 2 ) reagiert.…”

“…[1] Erst kürzlich untersuchte unsere Gruppe in Zusammenarbeit mit Covestro [NEt 3 Me]Cl als praktisches Chlorspeichermedium, das durch Zugabe von Chlor das entsprechende Trichlorid [NEt 3 Me][Cl 3 ] bildet. [2] Hervorzuheben ist, dass [NEt 3 Me][Cl 3 ] auch ein nützliches Chlorierungsmittel ist, welches mit Kohlenmonoxid zu der Basischemikalie Phosgen (COCl 2 ) reagiert. Unsere Untersuchungen deuten darauf hin, dass das Trichloridanion in [NEt 3 Me][Cl 3 ] eine ClÀ Cl-Bindung aufweist, die viel schwächer ist, als in elementarem Chlor, was die Insertion von Kohlenmonoxid in die ClÀ Cl-Bindung des Trichlorids erleichtert.…”