Temperature effect on the photo-epoxidation of propylene over V–Ti/MCM-41 photocatalyst

The effect of reaction temperature on the gas-phase photocatalytic epoxidation of propylene was systematically studied over V–Ti/MCM-41 photocatalyst at different temperatures (298–393 K). Temperature significantly influences the product distribution of photo-epoxidation. Raising temperature is favorable towards the formation of propionaldehyde (PA) due to inhibition of PA transformation to propionic acid (C2H5COOH), the intermediate product of acetaldehyde (AA). Results indicated that the reaction temperature has a dual-action to the reaction rate: (1) improving the desorption of reaction products, which provides more active sites for reaction and (2) reducing the adsorption of propylene on the photocatalyst, which declines the reaction efficiency.

The selectivity of products in the photo-epoxidation at different temperature conditions: (a) 298 K; (b) 323 K; (c) 348 K and (d) 393 K. Propylene oxide (PO), propionaldehyde (PA), acetone (AC), acetaldehyde (AA) and ethanol (ROH).Figure optionsDownload as PowerPoint slideHighlights
► Reaction temperature has a dual-action to the photo-epoxidation rate of propylene.
► Temperature significantly influences the product distribution of photo-epoxidation.
► Raising temperature is favorable towards the formation of propionaldehyde.