in the continuous catalytic polymerization of isobutylene , the exothermic heat of reaction is removed by vaporizing unreacted hydrocarbons , compressing and condensing the vaporized hydrocarbons to yield a liquid condensate at a pressure and temperature higher than that in the reaction zone , reducing the pressure on the liquid condensate to reduce its temperature to that of the reaction zone , separating any vapors thus formed and recycling the liquid condensate to the reaction zone . the process provides an energy efficient means of controlling reaction zone temperature . the process can be employed when using either a fluidized or fixed bed catalytic system .