Patent ID: 8871954

Claim:
A process for preparation of acetal derivatives particularly, DMDBS (1,3:2,4-bis (3,4-dimethylbenzylidene) sorbitol) and MDBS (1,3:2,4-bis (4-methylbenzylidene) sorbitol) by dehydrocondensation reaction between an aldehyde and alditol which comprises the following steps: dehydrocondensating an aldehyde and an alditol dissolved in a solvent by the addition of ionic liquid which acts as a catalyst under continuous stirring at a temperature of about 25° C. to about 80° C. to obtain a reaction mixture; subjecting the reaction mixture to filtration to obtain a solid mass and a mother liquor containing the solvent and ionic liquid; and purifying the solid mass by washing and drying to obtain an acetal derivative without any free acid residue present therein.