Facile Extraction and Salinization of Biotransferred 1,5-Pentanediamine to Produce Purified Nylon 56 Salt

Abstract

In this study, an extraction and salinization method was developed to treat the biotransferred 1,5-pentanediamine (PDA) to achieve the purification of PDA as well as the production of high-purity Nylon 56 salt. Further analysis showed that the Nylon 56 salt product with 99.6% purity and 95.11 g/L yield could be obtained by mixing 0.4 M n-butanol solution of self-produced PDA and n-butanol solution of commercial adipic acid in an equimolar ratio and reacting for 2 h at 323.15 K, 250 rpm. By comparison, the physical properties, structure, and thermal stability of the Nylon 56 salts produced by this process were basically the same as those of the Nylon 56 salt prepared with commercial technical grade PDA. The Nylon 56 salts were all in the form of short rod-shaped powder with initial polymerization and decomposition temperatures of 458.95 and 487.85 K, respectively. Therefore, this biotransferred PDA extraction–salinization coupling process omitted the distillation and dissolution steps of PDA, and the high-quality Nylon 56 monomer was produced by crystallization in the solution. The process achieves efficient high-purity production of Nylon 56 salt and provides a new idea for solving the problem of preparation and storage and transport safety of high-purity PDA.