Patent ID: 9029575
Filing Date: 2015-05-12
Classification: C07D,C07H

Abstract:
1. A process for preparation of acetal derivatives selected from the group consisting of DMDBS (1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol) and MDBS (1,3:2,4-bis(4-methylbenzylidene) sorbitol) comprising the following steps: preparing a quaternary ammonium salt based ionic fluid by adding a hydrogen donor and a ‘quaternary ammonium salt’ independently in equimolar quantities to at least one solvent; carrying out a dehydrocondensation reaction by adding an aldehyde and an alditol in a mole ratio of 2:1 in the ionic fluid under continuous stirring to form a reaction mixture; stirring the resultant reaction mixture to maintain the contents in a suspension form; discontinuing the stirring of the reaction mixture to allow the mass formed in the reaction mixture to settle and separating the supernatant ionic fluid containing mother liquor; and isolating and purifying the mass by filtering, washing and drying to obtain an acetal derivative without any free acid residue present therein.