The use of amines as sorbents for CO2 capture has been well established; in previous work we have shown that diethylenetriamine (DETA) forms a thermally reversible, zwitterionic adduct upon reaction with CO2.1 Sulfur dioxide has also been shown to react with DETA resulting in the formation of sulfite or sulfate salts depending on the reaction conditions.2 As a further step, the reactivity of these same gases with simple salts of protonated DETA has been investigated. Treatment of DETA with aqueous HCl, HNO3 and HBr yielded [DETAH]NO3, [DETAH]Cl and DETA.2HBr, respectively. Reaction of the nitrate and chloride salts with CO2 yielded [DETAH-CO2]NO3 and [DETAH-CO2]Cl, the structures of which were verified using X-ray crystallography. Interesting differences were observed in the geometries of the adducts - CO2 coordinates terminally in zwitterionic DETA-CO2 but to the central nitrogen in the ionic adducts. Currently, we are investigating this relationship and also studying the reactivity of SO2 with the acid salts. In reaction with SO2 a number of possible products can be envisioned, such as addition to the amine, formation of an oxysulfur salt, or formation of a halosulfite. Thus far reaction of DETA.2HBr with SO2 in water yielded the mixed bromide-sulfite salt, [DETAH3][SO3], analogous to the chloride salt previously obtained from the reaction of DETA and SO2in an ionic liquid.[1] Harper, N.D.; Nizio, K.D.; Hendsbee, A.D.; Masuda, J.D.; Robertson, K.N.; Murphy, L.J.; Johnson, M.B.; Pye, C.C.; Clyburne, J.A.C. Ind. Eng. Chem. Res. 2011  , 50, 5, 2822-30.[2] Murphy, L.J.; McPherson, A.M.; Robertson, K.N.; Clyburne, J.A.C. Chem. Commun. 2012  , 48, 1227-9

Reactivity of CO<sub>2</sub> and SO<sub>2</sub> with diethylenetriamine (DETA) and its salts

246th National Meeting (2013)

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Reactivity of CO2 and SO2 with diethylenetriamine (DETA) and its salts

Reactivity of CO₂ and SO₂ with diethylenetriamine (DETA) and its salts