Catalyst and process to produce branched unsaturated aldehydes

A system for preparing branched unsaturated aldehydes comprising:

• a reactor that receives a feedstock with 5 to 99.9% by weight Cn aldehyde, wherein n is 3 to 8, at an inlet, the reactor having resin with acid functional groups absent any metal from Group VIII;
• an exit stream that leaves the reactor, the exit stream having 10 to 99.99% by weight branched unsaturated C2n aldehyde and at least 92% selectivity of reaction to the branched unsaturated C2n aldehyde;
• a separation zone that receives the reactor exit stream and separates at least a portion of the branched unsaturated C2n aldehyde from the reactor exit stream as a crude product;
• and
• optionally a return line that recycles at least a portion of at least one of the remaining separation step exit streams to the reactor to be reprocessed in the reactor.