Process for preparing 2-phenyl-1,3-propanediol

A process for preparing 2-phenyl-1,3-propanediol comprising the steps:

• (a) treating 2-nitro-2-phenyl-1,3-propanediol with benzaldehyde, a compound of the formula (R.sup.1).sub.2 C(OCH.sub.3).sub.2 or with a combination of HC(OCH.sub.3).sub.3 and a ketone of the formula (R.sup.1).sub.2 C.dbd.O, wherein each R.sup.1 is C.sub.1 -C.sub.6 alkyl or the two R.sup.1 groups together with the carbon to which they are attached comprise a C.sub.5 -C.sub.6 cycloalkyl group, in the presence of an organic acid to form a nitro-dioxane of the formula ##STR21## wherein the groups R are both C.sub.1 -C.sub.6 alkyl or together with the carbon to which they are attached comprise a C.sub.5 -C.sub.6 cycloalkyl group, or wherein one R group is H and the other is phenyl;
• (b) reacting the nitro-dioxane of step (a) with H.sub.2 gas in the presence of a hydrogenation catalyst and an alcohol solvent to give a dioxane of the formula ##STR22## wherein R is as defined above;
• and (c) hydrolyzing the dioxane of step (b)
• (i) where both R groups are C.sub.1 -C.sub.6 alkyl or together with the carbon to which they are attached comprise a C.sub.5 -C.sub.6 cycloalkyl group, by treating with aqueous acid;
• or
• (ii) where one R group is H and the other is phenyl, by treating with H.sub.2 in the presence of a hydrogenation catalyst, an organic acid and an alcohol solvent;
• to form 2-phenyl-1,3-propanediol.