| 摘要 |
<p>New process is for the sepn. of an aq. soln. mixture by electrodialysis, the soln. mixt. contg. an essential aminoacid and a deriv. of this acid, one component being present in electrically charged form and the other in amphoteric form. Sepn. is into >=2 separate soln. prods. in the form of acid and prod., of which >=1 is obtd. in highly quantitative yield and contains highly pure prod. Through put and concn. of soln., and current density of applied current are adjusted to values which lead to the generation at the membranes of the feed cells concn.-polarisation conditions such that a high local concn. of protons accumulates on the surface of the anion-exchange membrane and a high local concn. of hycroxyl ions accumulates on the surface of the cation-exchange membrane. Independently of the isoelectric point of the aminoacid, the pH of the whole soln. in the feed cells is kept in the range 4-8 in order to equalise pH changes in the whole soln. resulting from inequalities in water decompsn. between the cation a and anion exchanger membranes. Used in sepn. of essential amino acids (useful in human and animal nutrition) such as lysine, tryptophan, histidine, phenylalanine, (iso)leucine, threonine, methionine, valine, or arginine from their derivs. (e.g. esters). The process is esp. useful for the working up of reaction mixts. resulting from optical resolution by stereospecific enzymatic hydrolysis.</p> |
