Operating the reaction to supply oxygenate at an oxygenate proportion index of at least 0.5, and controlling weight hourly space velocity and molar flow rate of oxygenate to the reactor to maintain {HEAD ~ a partial pressure velocity compensation factor} of {TAIL ~ at least 0.1 psia−1hr−1}, a prime olefin selectivity of at least 45 wt % can be maintained 
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Operating the reaction to supply oxygenate at an oxygenate proportion index of at least 0.5 , and controlling weight hourly space velocity and molar flow rate of oxygenate to the reactor to maintain { HEAD ~ a partial pressure velocity compensation factor } of { TAIL ~ at least 0.1 psia−1hr−1 } , a prime olefin selectivity of at least 45 wt % can be maintained
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH