CO₂ capture. Two new structures in the 2-amino-2-methyl-1-propanol (AMP) – water – CO₂ system

Energy production and transportation is responsible for more than 60 % of our CO₂ emission. In particular coal-fired power plants are big contributors. However, these large scale facilities offer the possibility to effective CO₂ capture through post-combustion processes. There are several options for such CO₂ capture. The problem is to make the absorption/desorption processes energetically and thereby economically viable. One process under investigation involves alkanoamines as absorbents in aqueous solutions. In these systems CO₂ is captured either by carbonate and/orcarbamate formation. We have studied the 2-amino-2-methyl-1-propanol (AMP) and the AMP-water phase diagramand its ability for CO₂ capture. The first crystal structure in the AMP – water system has been solved from powder diffraction data: AMP trihydrate (triclinic, P-1, a = 6.5897(3), b = 6.399 (2), c = 6.3399(2) Å and α = 92.40 (3), β =113.345(3) and γ = 94. 06(2) °). In the AMP – water CO₂ system two structures, a carbamate, AMPH-AMPCO₂ and a carbonate, (AMPH)₂-CO₃ are known [1]. In this work we solved a new structure from powder diffraction data, AMPH-HCO₃ hydrate (monoclinic, I2/a, a = 21.8522( ), b = 6.2149(15), c = 12.1300(3) Å, β = 104.036(16) °) readily formedwhen using <40 at% AMP in water.