title: Oscillatory symmetry breaking in the Soai reaction.
abstract: A kinetic model of spontaneous amplification of enantiomeric excess in the autocatalytic addition of diisopropylzinc to prochiral pyrimidine carbaldehydes is extended by a negative feedback process. Simulations based on the extended model result in large-amplitude oscillations both in a continuous-flow stirred tank reactor (CSTR) and in a semibatch configuration under optimized initial conditions. When sustained oscillations are maintained in a CSTR, no enantiomeric product distribution could be observed in the calculated series; the system keeps its initial enantiomeric ratio endlessly. During damped oscillations, or steady-state conditions, however, chiral amplification from a very small initial enantiomeric excess to more than 99% occurs in a semibatch configuration. Calculations indicated spontaneous enantiomeric product enrichment (i.e., accumulation of one of the enantiomers at the cost of the other one) from strictly achiral starting conditions in a semibatch configuration due to the inherent numerical error of the integrator method, which can be regarded as a model of the statistical fluctuation in the numbers of enantiomeric molecules.
authors.affiliation: Department of Chemistry, University of Debrecen, H-4010 Debrecen, Hungary. kmicskei@delfin.unideb.hu
authors.forename: Károly
authors.initials: K
authors.lastname: Micskei
authors.forename: Gyula
authors.initials: G
authors.lastname: Rábai
authors.forename: Emese
authors.initials: E
authors.lastname: Gál
authors.forename: Luciano
authors.initials: L
authors.lastname: Caglioti
authors.forename: Gyula
authors.initials: G
authors.lastname: Pályi
mesh_terms: D007700:Kinetics; D008956:Models, Chemical; D013237:Stereoisomerism