Researchers model the gas-phase reaction between methyl radical (CH3·) and ethene (C2H4) to form propyl radical (C3H7·) via a single, concerted C–C bond-forming step. A computational program classifies 1.0×105 simulated collisions at 600 K into three categories:
Category I Correct orientation and energy 240 events
Category II Correct energy but incorrect orientation 960 events
Category III Insufficient energy (orientation varied) 98 800 events
A newly developed pulsed electric field is applied that selectively re-orients ethene molecules so that 75 % of subsequent collisions have the reactive π bond aligned along the approach vector of CH3· while leaving the energy distribution unchanged.
(a) Using the original simulation data, calculate the empirical orientation factor Porig, defined as the fraction of energetic collisions that have the correct orientation.
(b) Assuming the pulsed field perfectly enforces the stated 75 % alignment on all energetic collisions, determine the new orientation factor Pfield.
(c) Compute the expected number of successful collisions out of the next 1.0×105 simulated events under the pulsed field.
(d) Critically evaluate two potential limitations of using external field alignment to enhance reaction rates in practical industrial reactors operating at high pressures.