Propionaldehyde, also known as propanal, is commonly utilized as an intermediate in organic reactions. It can be synthesized by the oxidation of propane in gas-phase. Photodissociation behavior of propionaldehyde has been investigated by the Paneth mirror method. The degradation mechanism of propionaldehyde on Rh(111) surface has been analyzed using temperature programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS). 2-?hloropropionaldehyde has been synthesized from propionaldehyde, via electrochemical chlorination. The presence of two stable rotamers in propionaldehyde has been reported based on microwave spectral data.