Process for the recovery of D- or L-{60 -amino-{68 -caprolactam hydrochloride of enhanced optical purity from mixtures of D- and L-{60 -amino-{68 -caprolactam hydrochloride

摘要

A process for the recovery of D- or L- alpha -amino- epsilon -caprolactam hydrochloride of enhanced optical purity from a mixture of D- and L- alpha -amino- epsilon -caprolactam hydrochloride, which comprises crystallizing out D-or L- alpha -amono- epsilon -caprolactam hydrochloride from a solution of D- alpha -amino- epsilon -caprolactam hydrochloride and L- alpha -amino- epsilon -caprolactam hydrochloride dissolved in a polar solvent, (1) the said solution containing, dissolved therein, at least one of the said D- alpha -amino- epsilon -caprolactam hydrochloride and L- alpha -amino- epsilon -caprolactam hydrochloride in the super saturated state and (2) the said solution comprising, in addition to the said D- and L- alpha -amino- epsilon -caprolactam hydrochloride, A. a basic substance having pKb value of not greater than 5 as measured at 29 DEG C. in water or substance having a basicity equivalent thereto, and/or B. a salt of mixture of D- and L- alpha -amino- epsilon -caprolactam having a solubility in the said polar solvent which is greater than the solubility of D- and L- alpha -amino- epsilon -caprolactam hydrochloride in the said polar solvent AND RECOVERING THE CRYSTALLIZED PRODUCT.