Selective Decarboxylation of L-Lysine to Produce Biobased 1,5-Pentanediamine

The ever-growing consumer preference for environmentally friendly plastic products is fueling the expansion of the biopolymer market. This trend has created a high demand for innovative processes that generate monomers from biomass feedstocks, providing a sustainable alternative to traditional fossil-based resources. This report details the synthesis of amino acid-derived 1,5-pentadiamine as a surrogate for hexamethylene diamine for Nylon synthesis. Current methods for diamines rely on toxic and environmentally damaging substances, such as cyanide and
ammonia. This study explores the decarboxylation of amine-rich L-lysine for diamine synthesis using carbon supported ruthenium catalysts, aiming to improve reaction selectivity and efficiency. Various analytical techniques, including GC-MS, GC-FID, and HPLC-PDA, were
employed to characterize reaction products. Preliminary results indicate a lysine conversion of up to 99.8% with a 36.0% amine selectivity attained at 200 °C and within 2.5 h. Two alternate systems were separately tested: (1) Protection of the substrate's amines with fluorenylmethyloxycarbonyl protecting groups and (2) Substitution of ruthenium catalysts with pyridoxine, a precursor to the decarboxylase enzyme cofactor pyridoxal phosphate. Future work includes improving current maximum 1,5-pentanediamine yield of 4.7% starting with further rigorous experimentation with ruthenium catalysts.