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A system which recirculates reactants from a stirred vessel through a remote reactor is described. Highly reproducible kinetic measurements are achieved for liquid phase reactions in general and those requiring isolation in particular. Typical reactions which require isolation involve high pressure, intense radiation, explosive mixtures, etc. The conversion history within the vessel is related to reaction rate through a mathematical model which facilitates interpretation of kinetic data. The stirred vessel is modeled as a perfectly uniforni reservoir coupled to the arbitrary reaction element by two transfer lines modeled as time delays. The analysis includes the effects of a parabolic velocity profile attendant to the use of low circulation rates or high viscosities. Analytical solutions are obtained for limiting cases and the model system simulated on an analog computer. The results are compared to experimental data on a radiation induced vinyl polymerization. ecycling reactor systems have broad application R in experimental kinetic analysis and have been used in studies of gas phase heterogeneous catalysis('**'. In these studies the recirculation rate was maintained so high that t h e reactor operated as a differential reactor and no appreciable concentration differences developed within the system. Under such circumstances, the system behaves as a batch reactor. The purpose here is to extend the analysis of the recirculating reactor system providing a method for interpreting conversion data obtained under circumstances where the conversion per pass is significant.A further objective is to consider liquid phase reaction in a remotely located reactor. Results obtained using a recirculating reactor system to study a radiation initiated polymerization will be presented. ApparatusThe reactor system is shown schematically in Figure 1. Details of the construction a r e discussed else-wherec3'. The system consists of an agitated vessel connected to a tubular reactor by relatively long transfer lines. The tubular reactor is located i n a high intensity Co-60 irradiator which supplies t h e yradiation used to initiate the reaction. I n operation, the reactant mixture is continuously recirculated from the agitated vessel through the flow reactor and returned to t h e vessel. Samples for conversion analysis a r e withdrawn from the vessel discharge and/or from the return transfer line.I n the present work t h e long transfer lines were necessitated by the twelve feet of water used to shield the irradiation source. These lines were not only long but relatively large to permit transfer of viscous polymer solution with reasonable pressure drop. Approximately one-fourth of the total reactant volume was contained in the transfer lines. Numerous other cir-0000000D000000000D00000000000000000oooo0000000000000000000000000000000000~ IPreseiit address :On dkcrit un systeme de re-circulation des produits de reaction d'un recipient agitC au moyen d'un rbacteur BoignC. On obtient des mesures cinetiques bien reproductibles dans le cas d...

Radiation induced solution polymerization of styrene in methylene chloride in a small scale pilot plant utilizing a flow reactor is reported. Both conventional free radical and ionic polymerization have been achieved. With rigorous drying accomplished over molecular sieves the ionic mechanism predominates. Conclusive kinetic evidence as well as polymer properties substantiate radiation induced ionic polymerization for the first time in an engineering pilot plant. The validity of Williams' model is reinforced by this study and a survey of over 100 literature observations.