Patent ID: 7141702

Claim:
A process for preparing an α-substituted acrolein having the formula CH2═CR—CHO, wherein R is an alkyl group or an aryl group, comprising: (i) subjecting a mixture of an olefin and syngas or a mixture of an olefin, carbon monoxide and hydrogen to hydroformylation in an organic phase in the presence of a hydroformylation catalyst or catalyst precursor that is a rhodium complex catalyst or catalyst precursor to obtain the corresponding aldehyde; and (ii) subjecting the aldehyde obtained in step (i) to aldol condensation with formaldehyde in an aqueous phase in the presence of an aldolisation catalyst that is a secondary amine or a secondary amine/organic acid catalyst, wherein reactions (i) and (ii) are carried out simultaneously in a biphasic aqueous-organic system, and the hydroformylation catalyst and the aldolisation catalyst are segregated in the two phases.