Abstract: An improved process for producing 1,5-pentamethylene diisocyanate (PDI) from a cadaverine salt is described herein. The process generally comprises providing a solution comprising a cadaverine salt dissolved in an inert solvent in the presence of a tertiary amine base; and subjecting the solution to a liquid-phase phosgenation reaction to convert the cadaverine to PDI. The phosgenation reaction comprises a step of maintaining the reaction at temperatures between 100° C. and 120° C. for a sufficient time to achieve a desired threshold yield of PDI. The processes described herein enable reductions in the amounts of reactants consumed, reaction temperatures, and/or overall reaction time, as compared to conventional phosgenation reactions. Employing a bio-based cadaverine salt that was not previously subjected to distillation is found to be advantageous, since subjecting cadaverine to high temperatures leads to the formation of certain cyclic compounds that are carried over to the PDI produced.

Abstract: Improved processes for producing bio-based nylon precursors having reduced organic and inorganic impurities are described herein. The processes generally comprise fermenting a microorganism engineered to produce lysine in a modified culture medium having low or reduced inorganic ion content, such as by employing a culture medium having an ammonium dicarboxylate buffering system that is preferably devoid of non-essential inorganic ions, and crystallizing the lysine directly from the spent lysine fermentation supernatant by adding a sufficient amount of a dicarboxylic acid. Such strategies aim to produce lysine dicarboxylate salt crystals that are employable in a downstream bioconversion step for the production of cadaverine dicarboxylate salts having reduced organic and inorganic impurities, which improve their downstream performance, for example in polymeration reactions for polyamide synthesis.

Abstract: Provided is a method for resolving an optical isomer from a racemate by using supercritical fluid extraction technology. The method is mainly applied to the separation of a product obtained after enzymatic resolution. Taking a preparation process of D-pantolactone as an example, the key point is to separate D-pantolactone and L-pantolactone from an enzymatic resolution liquid by means of supercritical fluid extraction.

Abstract: Provided is a method for preparing ?-alanine, the method comprising: preparing a ?-alanine product from a reactant containing fumaric acid and aqueous ammonia in the presence of a catalyst, wherein the catalyst contains a catalyst composition containing aspartase and L-aspartic acid-?-decarboxylase, and adding fumaric acid during the reaction, wherein the total moles of the fumaric acid added is equal to the initial moles of the aqueous ammonia in the reactant minus the initial moles of the fumaric acid in the reactant. Also provided are methods for preparing a ?-alanine salt (in particular calcium ?-alanine, sodium ?-alanine, and potassium ?-alanine) and a pantothenate (in particular calcium pantothenate, sodium pantothenate, and potassium pantothenate).

Abstract: Disclosed is a method for resolving an optical isomer from a racemate by means of electrodialysis. Specifically, an electrodialysis technique is used in an enzymatic resolution process, mainly in the separation of products after enzymatic resolution. Taking a preparation process for D-pantolactone as an example, the key point is that D-pantoic acid and L-pantolactone are separated from an enzymatic resolution solution by means of an electrodialysis method, which replaces the existing organic solvent extraction method. The process method is simple and easy to operate, has a high yield of D-pantoic acid of a good purity, greatly reduces the usage amount of an organic solvent, reduces production costs and is environmentally friendly, such that the working environment of workers can be improved to a great extent, and the operation safety index is improved.