ACCELERATION OF CHEMICAL-REACTION IN REACTIVE EXTRUSION ACCOMPANIED BY DEVOLATILIZATION

This work concerns the reaction acceleration in bubble enhanced devola tilization (DV) occurring in reactive extrusion (REX), to provide furt her evidence that overall reactivity can be enhanced by boiling. Using monoesterification of a styrene-maleic anhydride copolymer with an al cohol as a model reaction, the rate increase was determined by compari ng the conversions of the samples collected at different screw locatio ns with those predicted from the combined kinetic equation for the bub ble free homogeneous system and the RTD information obtained from both the RTD measurements and theoretical calculations. Significant reacti on acceleration was observed. The reaction enhancement was found to be more significant than found previously by batch operation. Also, the reaction enhancement beyond the DV zone showed a trend consistent with the previous observations in batch after DV has been halted. Further, we show that the apparent reaction rate increase during continuous RE X/DV is caused by local mass transfer effects, in agreement with the p revious work in batch. The good agreement between the theoretical pred ictions and the experimental results, observed here, lends some extend ed generality to the mass transfer model for reaction acceleration dur ing REX/DV.