Question

Q2) The following reactions were found to occur while trying to make a desired product B (1) A— B -rai = kic A-X - A2 = k2ACA A +X-Y -1A3 = k3A CĄCX Species X and Y are both foul pollutants a) What is the instantaneous selectivity of B with respect to the foul pollutants X and Y? b) How would you carry out this reaction to maximize the formation of B? Additional Information k1A = .5 -10,000/T min-1, T in degrees Kelvin k2A = 50 e-20,000/T min-1, T in degrees Kelvin k3A = 100 e-5,000/T min-1, T in degrees Kelvin

Answer 1

a) Selectivity is the ratio of the production rate of the desired component to the undesired component

from the above statement, we can write,

where, s = instantaneous selectivity

rb= desired product

  rx= undesired product

  ry= undesired product

Now   rb= K1A C2A

  rx= K2A CA

      ry= K3A CA Cx

therefore we can write, S = (K1A C2A)/( K2A CA *K3A CA Cx)

= K1A/  K2A K3A Cx

b) To maximize the desired product the reaction temperature should be intially high followed by low