ACTIVATION OF ETHANE IN THE PRESENCE OF SOLID ACIDS - SULFATED ZIRCONIA, IRON-PROMOTED AND MANGANESE-PROMOTED SULFATED ZIRCONIA, AND ZEOLITES

Ethane was activated in the presence of solid acids [sulfated zirconia (SZ), iron- and manganese-promoted sulfated zirconia (FMSZ), HZSM-5, and USY zeolite] at 1 atm, 200-450 degrees C, and ethane partial press ures in the range 0.01-0.2 atm. The data were measured with a flow rea ctor at low conversions (< 0.005) such that reaction of ethane took pl ace in the near absence of alkenes. Catalysis was demonstrated for eth ane conversion in the presence of FMSZ at 450 degrees C and 0.2 atm et hane partial pressure, but the reactions were not shown to be catalyti c for the other solid acids and other conditions. FMSZ was active for converting ethane into methane, ethene, and butane at an ethane partia l pressure of 0.2 atm and at temperatures of 200-300 degrees C; the ot her solid acids had no detectable activities under these conditions. A t higher temperatures, each of the solid acids was active for conversi on of ethane into ethene; butane and methane were also formed in the p resence of FMSZ, HZSM-5, and USY zeolite, whereas methane was the only other hydrocarbon observed in the presence of SZ. The initial (5 min on stream) selectivities to ethene at approximately 0.1% conversion, e thane partial pressure of 0.2 atm, and 450 degrees C were approximatel y 98, 94, 97, and 99%, for SZ, FMSZ, HZSM-5, and USY zeolite, respecti vely, Under the same reaction conditions, the initial rates of ethane conversion were 0.15 x 10(-8), 3.5 x 10(-8), 3.9 x 10(-8), and 0.56 x 10(-8) mol/(s.g) for SZ, FMSZ, HZSM-5, and USY zeolite, respectively. The reactivities are consistent with chemistry analogous to that occur ring in superacidic solutions and with the suggestion that FMSZ is a s tronger acid than the others investigated here. (C) 1997 Academic Pres s.