The present invention provides one-step processes for the production of chlorinated and/or fluorinated propenes. The processes provide good product yield with low, e.g., less than about 20%, or even less than 10%, concentrations of residues/by-products. Advantageously, the processes may be conducted at low temperatures than 500°C so that energy savings are provided, and/or at higher pressures so that high throughputs may also be realized. The use of catalysts or initiators may provide additional enhancements to conversion rates and selectivity, as may adjustments to the molar ratio of the reactants.