Abstract: It is intended to provide methods of producing a chlorine gas having a small bromine content, an aqueous sodium hypochlorite solution having a small bromic acid content, and liquid chlorine having a small bromine content. More specifically, a chlorine gas is produced by a method comprising the steps of: (A) washing a chlorine gas that contains bromine, in a gas washing unit composed of a packed column or a tray tower, wherein the chlorine gas introduced via a lower part of the gas washing unit is brought into counterflow gas/liquid contact with a liquid chlorine introduced via an upper part of the gas washing unit; and (B) taking out a purified chlorine gas thus washed, via the upper part of the gas washing unit, wherein a weight ratio of the chlorine gas and the liquid chlorine introduced in the step (A) is 1/1.0 to 1/0.3.

Abstract: The present invention is to provide a purification method of obtaining N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine of high quality in good yield with high productivity, which is accordingly suited for commercial scale application. An impurity-contaminated N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine is crystallized from a mixed solvent of alcohol and water in a volume ratio of alcohol/water being 1 to 20 to remove a contaminating impurity into a mother liquor and give crystals of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine.