Process for preparing dibenzylidenesorbitol and composition containing the same

Claim 1

In a process for preparing dibenzylidenesorbitol by dehydrocondensation of 1 mol of sorbitol with 2 mols of benzaldehyde in the presence of an acid catalyst, the improvement in which the reaction is carried out in two stages; the first-stage reaction comprising reacting, at a temperature of 50° to 70° C., benzaldehyde with an aqueous solution of sorbitol having a sorbitol concentration of at least 70%, in the presence of 0.03 to 0.5 part by weight of an acid catalyst per part by weight of sorbitol; the first-stage reaction being shifted to the second-stage reaction by adding water, as a reaction medium, and an additional amount of an acid catalyst to the first-stage reaction mixture when the conversion of sorbitol to dibenzylidenesorbitol reaches 10 to 40% in the first-stage reaction, the amount of the added water being such that the amount of water in the reaction system during the second-stage reaction is at least 2.5 parts by weight per part by weight of sorbitol charged to the first-stage reaction, the amount of the additional acid catalyst being 0.02 to 0.5 part by weight per part by weight of sorbitol charged to the first stage-reaction; the second-stage reaction comprising reacting the resultant mixture in the suspended state at a temperature of 15° to 25° C.; the resulting dibenzylidenesorbitol being obtained as an aqueous suspension thereof.