Reactive extraction for the recovery of primary amines from aqueous streams

Biotechnological transformations promise to be an ecologically and economically efficient alternative for the production of amines and amino alcohols. Limitations in the use of these transformations often arise from inhibitory effects due to amine toxicity or from unfavorable reaction equilibrium. One solution to overcome these limitations is the continuous recovery of the amine from the biotechnological reaction media via a suitable in situ product removal strategy such as liquid-liquid reactive extraction. In this study, we investigate liquid-liquid reactive extraction for the recovery of 3-methylbutylamine, 1-phenylethylamine and 3-amino-1propanol from aqueous streams, using a mixture of oleic acid and 1-octanol. For all investigated amines, high extraction yields of up to 99% and back extraction yields of over 90% of the extracted amine were observed. Relevant parameters such as chemical structure of the amine, the aqueous pH and the oleic acid concentration were identified. Furthermore, a mass action law was used to derive individual extraction constants for each amine allowing a mathematical description of the extraction behavior. This mathematical description provides a tool for the design of a tailor made reactive extraction system for the efficient recovery of amines while respecting given biotechnological pH requirements.

Automated summary

Biotechnological transformations offer an efficient alternative for producing amines and amino alcohols, but face limitations due to amine toxicity and reaction equilibrium. This study explores liquid-liquid reactive extraction for recovering amines from aqueous streams, achieving high extraction yields and providing a mathematical tool for designing tailor-made extraction systems while meeting biotechnological pH requirements.