THE EFFECT OF PHOSPHORUS ADDITIONON THE ACTIVITYOF BISMUTH MOLYBDATE CATALYST FOR PARTIAL OXIDATIONOF PROPYLENE TO ACROLEIN

ABSTRACT In order to examine the effect of phosphorus additiQnon the activity and selectivity of bismuth molybdate catalysts for partial oxidation of propylene to acrolein, three modes of phosphorus addition were performed. The three modes of Preparation were performed by (1) adding phosphorus into a-Bi2M03012to obtain Bi2PxM030yr(2) inserting phosphorus on bismuth sites to obtain Bi2.xPxM030ya,nd (3) inserting phosphorus on molybdenum sites to obtain Bi2PxMo3-XOyF.our major phases of bismuth phosphomolybdate were detected as the result of the phosphorus addition, namely a-Bi2M03012,BigPM0120s2,Mo03, and BiP04. Experimental results showed that the catalysts solely containing BiP04 and/or Mo03 have vel)\u27 low activities for partial oxidation of propylene to acrolein. Meanwhile, catalysts containing a-Bi2M03012and BigPM0120s2, together with either Mo03 or BiP04 showed on average the same activities as a-Bi2M03012and one of them (combination of a-Bi2M03012,BigPM0120s2and Mo03J has better performance than a-Bi2M03012at lower temperatures. The presence of the oxygen donor phase, i.e. BiP04 and Mo03, are believed to play a key role for the high activities of bismuth-phosphomolybdatecatalysts. However, at higher temperatures, the presence of oxygen donor reduces the catalyst selectivity to acrolein. Keywords: Propylene,Acrolein, Bismuth Molybdate,Partial oxidatio