Novel compounds for the capture of carbon dioxide from gaseous mixtures and subsequent release, related process and plant

Compounds for the absorption of carbon dioxide in the form of ionic liquids having the following general formula (I) or (II)

• wherein R3, R4, R5 are each independently H, a C1-C6 alkyl group or an aromatic group, R2 is a C1-C6 alkyl group, R1 is a C5-C19 alkyl group, and X− is a carboxylate anion of a natural or artificial amino acid,
• or in the form of glycerol esters having the general formula (III)
• wherein the groups R6, R7 and R8 are selected from H, an acyl group of formula R9—C(═OR)— where R9 is a C5-C19 alkyl group, an amino-acyl group deriving from a natural or artificial amino acid or an acyl residue of ectoin of formula (IV),
• and wherein at least one of the groups R6, R7, R8 is an acyl group of formula R9—C(═OR)— and at least one of the groups R6, R7, R8 is an amino-acyl group deriving from a natural or artificial amino acid or an acyl residue of ectoin of formula (IV),
• or in the form of esters, having the general formula (V)
• R10—OR—R11 (V)
• wherein R10 is a C5-C19 alkyl group and R11 is an amino-acyl group deriving from a natural or artificial amino acid or an acyl residue of ectoin of formula (IV).

Plant for the separation of CO2 from a gaseous mixture and subsequent release of CO2, comprising a column having:

• an absorption section (2) comprising means (5) for feeding a gaseous stream containing CO2, means (6) for feeding a stream of absorbent liquid, preferably in countercurrent with respect to said gaseous stream containing CO2, and means (8) for the exit of a gaseous stream deprived of CO2,
• a desorption (release of CO2) and regeneration section (3) in fluid communication with said absorption section (2), said desorption and regeneration section comprising output means (11) for a gaseous stream containing CO2 and output means (10) for a liquid stream of regenerated absorbent liquid,
• wherein said absorption section (2) and said desorption and regeneration section (3) each comprise a sequence of first areas (51) of liquid/gas exchange, preferably filled with a bed of inert material alternated with a sequence of second areas (52) for the collection of absorbent liquid and a plurality of interspaces (55) arranged externally and adjacent to corresponding first liquid/gas exchange areas (51), each of said interspaces (51) putting in fluid communication a second collection area (52) with a successive first exchange area (51) so as to transfer said absorbent liquid from a second collection area (52) to a first exchange area (51) subsequent thereto,
• a jacket (56) outside said absorption section (2) and a jacket (56) outside said desorption and regeneration section (3), each run through by a thermal exchange fluid to carry out a thermal exchange between the absorbent liquid running through said interspaces (55) and said thermal exchange fluid.