THERMAL DECOMPOSITION OF POLYCYCLIC ACETATES OVER HZSM-5 ZEOLITE IN FLOW-VACUUM CONDITIONS

The thermal decomposition of the 10,11 -dihydro-5H-dibenzo[a,d]cyclohepten-5-acetate (7), 5H-6,7-dihydrodibenzo[a,c]cyclohepten-6-acetate (8) and 6-hydroxymethyl-6H-5,7-dihydrodibenzo[a,c]cycloheptene's acetate (9) in flow-vacuum conditions: advanced vaccum (0,1-0,2 Torr), inert atmosphere (argon), 250-350 degrees C, over HZSM-5 zeolite was studyed. The products' distributions were determined by GC/MS using authentic samples. In order to explain the formation of the main reaction products, reaction mechanisms involving carbenium ions were suggested. A comparison between the thermal behavior of polycyclic acetates 7-9 in flow-vacuum conditions over zeolite and quartz as catalyst was disscused.