Method for producing polyunsaturated fatty acid-containing composition

A method for producing a composition comprising a polyunsaturated fatty acid, comprising:

• supplying an aqueous solution comprising a silver salt into a raw material solution comprising an alkyl ester of the polyunsaturated fatty acid such that the aqueous solution comprising the silver salt falls downward in the raw material solution, thereby contacting the aqueous solution comprising the silver salt with the raw material solution, wherein, after said contacting. the aqueous solution comprising the silver salt exists in a form of a dispersed phase and the raw material solution comprising an alkyl ester of the polyunsaturated fatty acid exists in a form of a continuous phase;
• and
• collecting the aqueous solution that has been contacted with the raw material solution,
• wherein the temperature of the aqueous solution that is to be contacted with the raw material solution is from 5 to 30° C., and
• the supply of the aqueous solution and the collection of the aqueous solution are carried out concurrently with each other.

An apparatus for producing a composition comprising a polyunsaturated fatty acid,

• the apparatus comprising a first reaction vessel,
• wherein the first reaction vessel comprises a raw material solution inlet port through which a raw material solution comprising an alkyl ester of the polyunsaturated fatty acid is to be supplied into the reaction vessel, an aqueous solution inlet port through which an aqueous solution comprising a silver salt is to be supplied into the reaction vessel, an aqueous solution collection port through which the aqueous solution that has been contacted with the raw material solution is to be collected, and a raw material solution collection port through which the raw material solution that has been contacted with the aqueous solution is to be collected,
• the raw material solution inlet port is arranged at the lower part of the first reaction vessel and above the aqueous solution collection port,
• the aqueous solution inlet port is arranged at the upper part of the first reaction vessel, above the raw material solution inlet port and below the raw material solution collection port,
• the aqueous solution comprising the silver salt which has been supplied through the aqueous solution inlet port flows downward in the first reaction vessel and the raw material solution which has been supplied through the raw material solution inlet port flows upward in the first reaction vessel while flowing countercurrently to each other in the reaction vessel so that the aqueous solution and the raw material solution are contacted with each other, and the contacted aqueous solution is collected outside the reaction vessel through the aqueous solution collection port, and
• wherein the first reaction vessel further comprises a liquid distributor for converting the aqueous solution to be supplied through the aqueous solution inlet port into a dispersed phase.