Sigma seems to have two products listed for sale as "Cinnamic Aldehyde". One compound clearly seems the trans isomer but the other one seems like an unspecified mixture. (They even have two different CAS nos.: 14371-10-9 vs 104-55-2 )
What surprises me is that the corresponding SDS lists the Flash Point of one as 71°C and the other as 125°C.
Is this really possible or is this just an error? The boiling points listed seem fairly close: 250°C vs 248°C.
P.S. Even if one accounts for methodological differences in Flash Point Determination e.g. closed cup vs open cup those are typically at worst 10°C apart. Here the flash points seem a good 55°C apart.