A process for removal of acid gases from fluid stream, wherein the fluid stream is brought into contact with an absorbent to obtain a treated fluid stream and a laden absorbent, the absorbent comprising a diluent and a compound of the general formula (I) wherein R1 is selected from C1-C8-alkyl and C2-C8-hydroxyalkyl; R2 is selected from hydrogen and C1-C8-alkyl; R3 is selected from hydrogen and C1-C8-alkyl; R4 is selected from hydrogen and C1-C8-alkyl; R5 is C1-C8-alkyl; with the proviso that at least one of the following conditions (i) and (ii) is met: (i) R5 is C3-C8-alkyl bound to the nitrogen atom via a secondary or tertiary carbon atom; (ii) when R4 is hydrogen, R3 is C1-C8-alkyl; or when R4 is C1-C8-alkyl, at least one of R2 and R3 is C1-C8-alkyl; and n is an integer from 0 to 6. Further provided is an absorbent for the absorption of acid gases from a fluid stream, comprising a diluent and a compound of the general formula (I) as defined above, as well as the use of a compound of the general formula (I) as defined above for removal of acid gases from a fluid stream. The absorbents are useful for the selective removal of hydrogen sulfide from fluid streams and have high acid gas loading capacity, high stability, and low volatility.