Catalysis of Organic..

Singh and Chuang 1050.064m/e = 32 (O 2 ) m/e = 41 (C 3 H 6 )0.05Flow Rate (ml/min)32m/e = 29 (propionaldehyde)m/e = 2 (H 2 )Flow Rates (ml/min)0.040.030.02m/e = 58 (propylene oxide)100.01m/e = 43 (acetone)0m/e = 44 (CO 2 ) m/e = 45(iso-propanol)50 100 150 200 250Temperature(°C)50 100 150 200 250Temperature (°C)Figure 5. Calibrated MS profiles of reactants and products during TPR of propylenepartial oxidation over Au/TiO 2 -SiO 2 (Catalyst weight = 0.14 g).TPR results over Au/TiO x -SiO 2Fig. 6 shows the IR-TPR of C 3 H 6 partial oxidation over Au/TiO x -SiO 2 . Theinteraction of Ar/C 3 H 6 /H 2 /O 2 with the catalyst surface at 50 °C led to decrease in theband intensity of OH vibration at 3741 cm -1 and the formation of a 1662 cm -1 (C=Oof adsorbed acetone ) band. Mass spec. results in Fig. 7 shows the reaction producedpropionaldehyde, acetone, and CO 2 . The rate of product formation peaked at 140 o C.Table 2 shows the activity of Au/TiO x -SiO 2 and Au/TiO 2 -SiO 2 for propylenepartial oxidation at 200 °C under transient condition.Table 2 Activity and selectivity of the catalysts during TPR studies at 200 °CCatalystWeight(gm)Conversion(%)C 3 H 6 /H 2 /O 2Selectivity(%)CO 2 /C 2 H 5 CHO/(CH 3 ) 2 CO/(CH 3 ) 2 COH/POAu/TiO x 0.085 11.7/46/4.8 10.2/74.8/13.6/0/0-SiO 2Au/TiO 2-SiO 20.140 22.7/76.2/19 4.8/71.4/21/1.8/0.91