r or s - 1 - phenyl - 1 , 3 - propanediols having optical purity of 100 % ee were obtained by recrystallization of r or s - 1 - phenyl - 1 , 3 - propanediols having optical purity of 20 % ee to below 100 % ee , the last diols are represented by the formula , ## str1 ## it is possible to obtain optically pure 1 - phenyl - 3 - propanediols from optically impure 1 - phenyl - 1 , 3 - propanediols by a simple method .