Sustainable separation of bio-based cadaverine based on carbon dioxide capture by forming carbamate

Abstract

Bio-based cadaverine, manufactured by the decarboxylation of l-lysine, is an important raw material. However, the extractive-distillation separation and purification of cadaverine from bioconversion fluids require high energy consumption and leads to the loss of self-released carbon dioxide during the decarboxylation of l-lysine. This study focuses on the green and sustainable separation of bio-based cadaverine based on the capture of self-released carbon dioxide by cadaverine forming carbamate. Results showed that granular-activated carbon JK1 shows the best decolorization efficiency and achieves a higher cadaverine yield. After three times of solventing-out crystallization, refined cadaverine carbamate with 99.1% purity and total 57.48% yield was obtained. It was also found that the refined cadaverine carbamate consists of mixed crystals having numerous structural forms that can easily dissociate carbon dioxide. Furthermore, the amine carbamate strategy may be of great value for the development of a green and sustainable separation mode of bio-based amines and carbon dioxide capture.

Scheme 1. Preparation process of cadaverine carbamate.

Fig. 1. Effects of activated carbon types on the decolorization efficiency and cadaverine yield in the concentrated cadaverine solution.

Fig. 2. Effects of the content of activated carbon (a), decolorization speed (b), decolorization time (c), and decolorization temperature (d) on decolorization efficiency and cadaverine yield in the concentrated cadaverine solution.

Fig. 3. Effects of the deprotonation cadaverine concentration in the n-butanol extraction solution on purity and yield of cadaverine carbamate.

Fig. 4. Effect of the number of solventing-out crystallization on purity and yield of cadaverine carbamate.

Fig. 5. (a) FTIR of crude and refined cadaverine carbamate; (b) TGA of refined cadaverine carbamate; (c) XRD of the refined cadaverine carbamate; (d) HPLC of the refined cadaverine carbamate and free cadaverine; (e) GC-MS spectroscopy of refined cadaverine carbamate and free cadaverine.

Fig. 6. ¹³C NMR spectroscopy of refined cadaverine carbamate (a) and free cadaverine (b); ¹H NMR spectroscopy of refined cadaverine carbamate (c) and free cadaverine (d); refined cadaverine carbamate was dissolved in D₂O and free cadaverine was dissolved in CDCl₃.