The thermal decomposition of acetaldehyde

Abstract

This paper contains a more detailed study than has hitherto been made of the effect of surface and vessel size on the thermal decomposition of acetaldehyde. This was desirable in view of the suggestion recently made that the reaction might take place by a chain mechanism, and also because the validity of the previous evidence that the reaction is homogeneous has been called in question. In an unpacked silica between 500° and 600° the reaction is attended by a pressure increase which is about 98% of that corresponding to the equation CH 3 CHO = CH 4 + CO, and the gaseous products consists of equal parts of carbon monoxide and methane. When a packed vessel with very large surface is used the pressure increase is rather less than the theoretical, indicating that some condensation reaction occurs which is probably heterogeneous in contrast with the principal decomposition.