Valine p-isopropylbenzene sulfonate and a process for purifying valine

摘要

The present invention addresses the need to provide a process for purifying valine having a high purity in high yield by a simple method and using an inexpensive precipitant. A valine-containing aqueous solution is reacted with p-isopropylbenzenesulfonic acid or its water-soluble salt to form a valine p-isopropylbenzenesulfonate crystal. Valine p-isopropylbenzenesulfonate is separated and then dissociated to purify and obtain valine. The p-Isopropylbenzenesulfonic acid used may be in the form of a free acid, or a salt eg an alkali metal salt or an ammonium salt. The procedure of forming an adduct comprising 1 mol of valine and 1 mol of p-isopropylbenzenesulfonic acid and purifying valine has the effects that since the solubility of valine p-isopropylbenzenesulfonate is low, valine may be obtained at high efficiency, and that valine may be separated at a high rate from leucine and isoleucine, which are in general hard to separate from valine, because of the specificity of the adduct. p-Isopropylbenzenesulfonic acid can be easily produced by sulfonating inexpensive isopropylbenzene.