Separation and Microdetermination of Acrolein and Propylene by means of Detector Tubes

Abstract

When 100cc of air containing acrolein and propylene was passed at the rate of 1cc/sec into the detector tube which contained hydroxyl amine hydrochlo ride and thymol blue on silica gel as detecting agent, acrolein discolored and coexisting propylene had no effect. Acrolein concentration (0.003-3.0%) was determined by measuring the length of discolored layer.
Coexisting propylene was determined by means of the detector tube which contained sulphuric acid and chromic acid on silica gel (from orange to greenish black, measuring range 0.05-5.0%) or palladium sulphate and ammonium molybdate on silica gel (from pale yellow to blue, measuring range 0.01-1.0%). Acrolein detector and propylene detector were connected in series and 20cc of the mixed gas was sent at the feeding rate of 0.2cc/sec. Acrolein was absorbed by acrolein detector and eliminated. Propylene was determined with propylene detector by measuring the length of discolored layer. Acrolein detector absorbed a small portion of propylene which was removed by feeding pure air and sent to another propylene detector. Propylene concentration was determined by summing up the readings of two propylene detectors. Relative error of proposed method was within±10%.