A reaction sequence involving 11 chemical species was incorporated into a mathematical model of an electrolytic cell consisting of an undivided parallel-plate reactor operating under steady, continuous flow conditions. The set of coupled, nonlinear, stiff differential equations was solved numerically by dynamic simulation. The technique was applied to the paired synthesis of propylene oxide from propylene-saturated bromide electrolyte. For this system, the eigenvalues associated with the jacobian ranged over ten orders of magnitude. The effect of pH, [Br-], mass transfer, space time, and current density were explored to understand their influence on yield, selectivity, conversion, current efficiency, and cell voltage. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-08 to IP Vol. 132,No. 8 COMPLEX REACTION SEQUENCES ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-08 to IP Vol. 132, No. 8 COMPLEX REACTION SEQUENCES ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-08 to IP

Operation of electrosynthesis reactors with 60 Hz transmission power modulates the electrode potential as a sine wave with no dc offset voltage. Alternating polarity alternating voltage (APAV) describes the synthesis because an electrode changes polarity every half cycle. In APAV electrosynthesis, products from electrode reactions must be removed from the electrode to prevent back reaction and loss of net current efficiency before the next half-cycle. An experimental study was made of the bromine current efficiency in the indirect electrosynthesis of alkene oxides. Reduction of soluble electrogenerated bromine at polarity reversal decreased the current efficiency for the production of bromine. High mass transfer, rapid homogeneous reaction, and low current density conditions produced high bromine current efficiencies. Bromine current efficiency was correlated as a function of three dimensionless numbers incorporating the homogeneous reaction rate constant, mass transfer coefficient, frequency, average current density, and exchange current density. A mass transfer criterion predicted process conditions required to produce bromine at 95% current efficiency. The correlations were applied to determine the suitability of a candidate chemical pathway for APAV electrosynthesis. Electrogenerated species in direct and indirect syntheses can be produced at 95% current efficiency with km/(D~) ~ above 5.6. Electrogenerated species in indirect syntheses with rapid homogeneous reactions can be produced at 50 to 95% current efficiency with 0.