FR 4596 then FR 6300 at Barcelona
Porto → Barcelona → Sofia
Timetable, Barcelona time
00:50FR 4596 from Porto at the gate
17:10FR 6300 to Sofia leaves the gate
16 h 20 apart on the timetable
FR 6300 leaves 16 h 20 after FR 4596 arrives on the timetable: more than half a day, so not a connection we count.