1. Field of the Invention
The present invention relates to a process for production of .alpha.-hydroxycarboxylic acid amide. More particularly, it relates to a process for producing .alpha.-hydroxycarboxylic acid amide by a hydration reaction of cyanhydrin in a liquid phase.
.alpha.-Hydroxycarboxylic acid amide is used as a starting material for production of .alpha., .beta.-unsaturated carboxylic acid ester through .alpha.-hydroxycarboxylic acid amide. In particular, in case of .alpha.-hydroxyisobutyric acid amide, methyl methacrylate is obtained through methyl .alpha.-hydroxyisobutyrate. This methyl methacrylate is very important for production of polymethyl methacrylate having excellent properties.
2. Description of Related Arts
Manganese dioxide as a catalyst for hydration of cyanhydrin into the corresponding .alpha.-hydroxycarboxylic acid amide is disclosed in West German Patent No. 2131813. .delta.-Type manganese dioxide as a catalyst for hydration of acetone cyanhydrin is described in U.S. Pat. No. 4,018,829.
In Japanese Patent Application Laid-Open Nos. 57534/1988 and 57535/1988, a process for preparation of a manganese dioxide catalyst in which zinc is introduced, and a process for preparation of a manganese dioxide catalyst by reducing potassium permanganate with hydrochloric acid are disclosed.
When, however, manganese dioxide prepared by the above processes is used as a catalyst as it is, problems arise in that catalytic activity is not sufficiently high, a large amount of the catalyst must be used, the yield of the desired amide is low, and the catalytic activity abruptly drops in a short time. Thus the processes have not been put into practical use.
It has been found that in production of .alpha.-hydroxycarboxylic acid amide from cyanhydrin, the activity of a manganese dioxide catalyst has a close relationship with zirconium, vanadium, or tin, and also with an alkali metal which exists in the catalyst. Based on the findings, the present invention has been accomplished.
USPTO Backgrounds
USPTO Backgrounds