Acrylonitrile → Acrylamide

Three jacketed glass columns, each column being charged with 40 parts of the above-prepared fixed cells, were connected in series. A mixed solution of 4 parts of acrylonitrile and 96 parts of a 0.1% aqueous solution of sodium acrylate (neutralized with Na2CO3 to pH 8.0) was introduced into the first column (hereinafter referred to as "Column No. 1") from the top thereof, and passed therethrough at a temperature of 5° C. and SV (Space Velocity)=0.8 hr-1. 96 parts of the reaction solution flowing out of Column No. 1 was mixed with 4 parts of acrylonitrile, introduced into the second column (hereinafter referred to as "Column No. 2") from the top thereof, and passed therethrough at SV=0.8 hr-1. The effluent from the bottom of Column No. 2 in the amount of 96.5 parts was mixed with 3.5 parts of acrylonitrile, introduced into the third column (hereinafter referred to as "Column No. 3") from the top thereof, and passed therethrough at a temperature of 5° C. and SV=0.8 hr-1. The reaction in each column proceeds smoothly without causing the trouble resulting from the swelling of the fixed cells. As an effluent from the bottom of Column No. 3, a 15.4% aqueous solution of acrylamide containing no acrylonitrile was obtained. This aqueous solution was vacuum-concentrated at 45° C. by use of a flash evaporator while bubbling air therethrough, to thereby obtain a concentrated solution having an acrylamide concentration of 28%.