Abstract: A production method for propylene is characterized in that ethanol is converted into propylene by continuously reacting ethanol on a catalyst. A solid acid catalyst is characterized in that the kinetic constant k of the butane cracking reaction on the catalyst at 500° C. is 0.1 to 30 (cm3/min·g), and the solid acid catalyst is used in the production method for propylene. A solid acid catalyst is characterized in that the aperture diameter of pores formed in surfaces of the catalyst is 0.3 to 1.0 nm, and the solid acid catalyst is used in the production method for propylene. Furthermore, a regeneration method for a catalyst is characterized in that a heating treatment in an oxygen atmosphere is perform on a catalyst that has been used to produce propylene in the production method for propylene of the invention.

Abstract: Disclosed is a process for producing an .alpha.,.beta.-unsaturated carbonyl compound represented by the formula [II]: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents a hydrogen atom or a hydrocarbon residue and may be linear or may form a ring in optional combination thereof and total carbon atom number of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is 12 or less, which comprises contacting oxygen with an alkenyl compound represented by the formula [I]: ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined above and X represents a trihydrocarbylsilyl group or an acyl group in the presence of a platinum group metal-supporting catalyst.