An absorbent for removing carbon dioxide from a fluid stream, comprising an aqueous solution a) of an amine of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; X is OH or NH(CR.sub.1R.sub.2R.sub.3); m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is 0 or 1; and b) at least one activator selected from b1) a sterically unhindered primary amine and/or a sterically unhindered secondary amine; and a carboanhydrase. The absorbent allows rapid absorption of carbon dioxide from fluid streams.

Disclosed herein are compounds of formula I: and salts thereof. Also disclosed are compositions comprising compounds of formula I and methods using compounds of formula I.

##STR00001##

Disclosed herein are compounds of formula I: and salts thereof. Also disclosed are compositions comprising compounds of formula I and methods using compounds of formula I.

##STR00001##

A compound of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.

A compound of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.

Disclosed herein are compounds of formula I: and salts thereof. Also disclosed are compositions comprising compounds of formula I and methods using compounds of formula I.

##STR00001##

Disclosed herein are compounds of formula I: and salts thereof. Also disclosed are compositions comprising compounds of formula I and methods using compounds of formula I.

##STR00001##

A process for removing hydrogen sulfide and carbon dioxide from a fluid stream comprises a) an absorption step in which the fluid stream is contacted with an absorbent comprising an aqueous solution (i) of an amine of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; X is OH or NH(CR.sub.1R.sub.2R.sub.3); m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is 0 or 1; and optionally (ii) at least one tertiary amine, where the molar ratio of (i) to (ii) is greater than 0.05; wherein at least 90% of the hydrogen sulfide is removed from the fluid stream and selectivity for hydrogen sulfide over carbon dioxide is not greater than 8, wherein a CO.sub.2- and H.sub.2S-laden absorbent is obtained; b) a regeneration step in which at least a substream of the CO.sub.2- and H.sub.2S-laden absorbent is regenerated and a regenerated absorbent is obtained; and c) a recycling step in which at least a substream of the regenerated absorbent is recycled into the absorption step a). The process allows a high level of hydrogen sulfide removal with a simultaneously high coabsorption of carbon dioxide.

A compound of the general formula (I)

##STR00001##

in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.

A compound of the general formula (I)

##STR00001##

in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.