| abstract |
1,2-Diols of the formula: <IMAGE> (I) where R1 and R2 are hydrogen, alkyl of 1 to 10 carbon atoms or such as alkyl substituted by a halogen, a hydroxy group, a phenyl group, a methoxy group, or an ethoxy group, a phenyl group or a furyl group or R1 and R2 together form an alkylene group of 2 to 7 carbon atoms are formed by hydrogenating a correspondingly substituted cyanohydrin in an aqueous medium first in the presence of a hydrogenation catalyst and an acid at a temperature between -20 DEG and +25 DEG C. and a hydrogen pressure of less than 10 bar until per mole of cyanohydrin employed there is taken up one mole of hydrogen and then the hydrogenation continued to the end of the absorption of hydrogen in the presence of metallic nickel at a temperature between 30 DEG and 100 DEG C. and a hydrogen pressure between 10 and 150 bar. |