Patent ID: 9718761
Date: 2017-08-01
CPC Classifications: B01J,C07C

Claim:
1. A method for producing α-hydroxyisobutyric acid amide by hydration of acetone cyanohydrin in the presence of a catalyst comprising manganese oxide using a reaction apparatus in which two to seven reaction regions are connected in series, wherein the method comprises: (B) cyclically supplying at least a portion of a reaction liquid withdrawn from at least one reaction region to a first reaction region (I) in the reaction apparatus; (b1) further cyclically supplying at least a portion of the reaction liquid withdrawn from at least one reaction region to at least one reaction region other than the first reaction region (I), and (C) supplying at least a portion of a reaction liquid withdrawn from at least one reaction region other than the first reaction region (I) to: i) at least one reaction region other than the first reaction region (I) which is the same as or upstream from the at least one reaction region other than the first reaction region (I) from which the reaction liquid is withdrawn, and ii) at least one reaction region other than the first reaction region (I) which is downstream from the at least one reaction region other than the first reaction region (I) from which the reaction liquid is withdrawn; wherein an oxidizing agent is supplied to at least one reaction region in the reaction apparatus, wherein the method further comprises supplying a reaction raw material liquid containing the acetone cyanohydrin to the reaction apparatus, and wherein the concentration of the acetone cyanohydrin in the total amount of the reaction raw material liquid is 30% by weight or more, and wherein the concentration of manganese eluted from the first reaction region (I) is less than or equal to 4.5 ppm.