| 摘要 |
PROBLEM TO BE SOLVED: To provide an industrially advantageous preservation method for optically active mandelic acid excellent in workability, safety and sanitation aspects stably preserving as an aqueous solution at a fixed pH below a fixed temperature. SOLUTION: Optically active mandelic acid is preferably preserved as an aqueous solution at pH 5-11 and temperature <=65 deg.C, preferably in an inert gas atmosphere. The concentration of the optically active mandelic acid in the aqueous solution is 5-20 wt.%. Nitrogen gas, argon gas or the like are enumerated as the inert gas. The concentration of oxygen is preferably <=1%. A glass, a metal such as stainless steel or the like, a resin or the like containers are cited as the container. The preferable preserving temperature of the aqueous solution of the optically active mandelic acid is 0-50 deg.C. The aqueous solution of the optically active mandelic acid is preferably preserved after adjusting pH by adding an alkali aqueous solution such as sodium hydroxide in the case of the pH of the solution <=5 and adding an aqueous solution of mineral acid such as hydrochloric acid or the like in the case pH >=11.
|
