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AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsShuji Ebata, Hiroyuki Hirayama, Hirofumi Higuchi, Koichi Kida
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A process for preparing an amide by hydrating a cyanohydrin with a denatured manganese dioxide catalyst. The catalyst is prepared by reacting an aqueous permanganate solution and an aqueous manganese (II) compound solution in an acidic aqueous solution at a temperature of 70.degree. C. to 150.degree. C.
A process for preparing an amide comprising subjecting a cyanohydrin to hydration reaction with the denaturated manganese dioxide catalyst prepared by the process comprising reacting an aqueous permanganate solution and an aqueous manganese (II) compound solution in an acidic aqueous solution at a temperature of 70.degree.C. to 150.degree. C.
Dependencies are inferred from the claim text.
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From nitriles by transformation of cyano groups into carboxamide groups: by hydration using metals or metallic ions as catalyst
Manganese, technetium or rhenium: manganese
Acyclic or carbocyclic compounds
Chemical or physical processes
Term ended 25 Jun 2010 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a process for producing a denaturated manganese dioxide catalyst for the hydration reaction of cyanohydrins. More particularly, the present invention relates to a process for producing efficiently manganese dioxide having a high catalytic activity for the hydration reaction of cyanohydrin in an aqueous phase.
2. Description of the Related Arts
The present invention will be described in detail below.
Manganese dioxide is used in the hydration reaction of cyanohydrins as already described above, in which manganese dioxide has a general composition of MnO.sub.1.7 to MnO.sub.2 and crystal structures such as .alpha., .beta., .gamma., .delta. and .epsilon.. Furthermore, in manganese dioxide, a transition between respective phases or a change in the crystallinity occurs so that its structure is very complicated and varied. While manganese dioxide is present in nature, it is usually prepared by the oxidation of manganese (II) compounds or the reduction of permanganate (VII) salts on its use as a catalyst.
The process according to the present invention belongs to the process for preparing a denaturated manganese dioxide from an excessive amount of a permanganate (VII) salt and a manganese (II) compound in an acidic aqueous solution.