Analysis of gas mixtures containing propylene oxide or acrylic acid, e.g. from the screening of oxidation catalysts, involves reaction with nicotinamide on a porous support followed by measurement of fluorescence

摘要

A method for the analysis of gas mixtures containing propylene oxide or acrylic acid involves passing the gas through a permeable substrate coated with nicotinamide, developing with acetophenone and potassium hydroxide followed by formic acid, and measuring the fluorescence of the reaction product. A method for the analysis of gas mixtures containing propylene oxide (PO) or acrylic acid (AA) involves (A) passing the gas over or through an analytical substrate which is coated with nicotinamide (optionally in combination with a matrix component, preferably glycerol) so that the nicotinamide reacts with any PO or AA, (B) treating the substrate with a 1-30 (preferably 5-15) wt% ethanolic solution of acetophenone and potassium hydroxide at a concentration of 0.1-1 (preferably 0.3-0.7) mol/l and allowing it to react with the products from stage (A) with ice cooling, (C) adding formic acid, preferably 50-99 wt% in water, heating at 50-150 [deg]C and optionally drying the substrate and (D) determining the fluorescence activity of the reaction product. Independent claims are also included for: (1) a gas-permeable analytical substrate (I) for the above method, coated on the surface with 0.1-50 wt% nicotinamide (optionally with a matrix component as above); (2) a test system for catalysts, with an array of catalysts on a gas-permeable reaction surface, a reaction gas inlet under the surface and an analytical substrate (I) directly above the catalysts or above a gas-permeable multi-channel substrate which is directly above the catalysts.